How to Produce Building Materials

Abstract

Methods of producing building materials are provided. The subject methods include preparing a carbonate precipitate comprising undifferentiated multipotent polymorphic precursors (i.e., polymorphic precursors) and treating the carbonate precipitate under conditions sufficient to produce a building material. The disclosed polymorphic precursors exist in an intermediate state between a disordered state (e.g., amorphous calcium carbonate (ACC)) and an ordered state (e.g., calcium carbonate or calcium magnesium carbonate polymorphs). Aspects of the invention also include building materials (e.g., aggregates), as well as compositions (e.g., concrete dry composites, settable compositions, and building structures) comprising the building materials produced via the subject methods.

Description

[Background technology]

[0001] Introduction Concrete is the most widely used engineering material in the world due to its ease of placement and high load-bearing capacity. Current global concrete consumption is estimated to be over 11 billion tons per year (Concrete, Microstructure, Properties and Materials (2006, McGraw-Hill)).

[0002] The main components of concrete are coarse and fine aggregates, air, and cement, such as Portland cement, plus water. Traditional concrete aggregates include sand, natural gravel, and crushed stone. Artificial aggregates may also be used, especially in lightweight concrete.

[0003] When the component materials are mixed together, the mixture hardens or hardens through the chemical process of hydration, in which cement and water react to bind the aggregates together to form a stone-like material. The proportions of the component materials affect the physical properties of the resulting concrete, and therefore the proportions of the mixture components are selected to meet the requirements of a particular application.

[0004] Portland cement is made primarily from limestone, certain clay minerals, and gypsum in a high-temperature process that releases carbon dioxide and chemically bonds the main components into new compounds. The energy required to burn the mixture consumes about 4 GJ per tonne of cement produced.

[0005] Cement production is currently a major source of carbon dioxide atmospheric emissions, as carbon dioxide is produced both by the cement production process itself and by the energy plants that generate the electricity to run the production process. Cement plants are estimated to be responsible for 5% of global carbon dioxide emissions. As global warming and ocean acidification become increasingly severe and the desire to reduce carbon dioxide gas emissions (the main cause of global warming) continues, the cement production industry will come under increasing scrutiny.

[0006] Fossil fuels used in cement plants include coal, natural gas, oil, used tires, municipal waste, petroleum coke, and biofuels. Fuels also come from coal gasification and biofuels produced using tar sands, oil shale, coal liquids, and syngas. Cement plants are a major source of CO2 emissions, both from the combustion of fossil fuels and from the CO2 released from the calcination that turns limestone, shale, and other ingredients into Portland cement. Cement plants also generate waste heat. Additionally, cement plants produce other pollutants such as NOx, SOx, VOCs, particulates, and mercury. Cement plants also generate cement kiln dust (CKD), which must be disposed of from time to time, often in hazardous landfills.

[0007] CO2 emissions have been identified as a major contributor to the phenomenon of global warming and ocean acidification. CO2 is a by-product of combustion, which creates operational, economic, and environmental problems. Increasing atmospheric concentrations of CO2 and other greenhouse gases are expected to promote the storage of heat in the atmosphere, leading to increased surface temperatures and rapid climate change. CO2 also interacts with the oceans, causing a drop in pH toward 8.0. CO2 monitoring indicates that atmospheric CO2 has increased from about 280 parts per million (ppm) in the 1950s to about 400 ppm today. The impacts of climate change can be economically costly and environmentally harmful. To mitigate the potential risks of climate change, CO2 needs to be sequestered. Summary of the Invention

[0008] Aspects of the invention include methods of producing building materials. The subject methods include preparing a carbonate precipitate, which may be a carbonate slurry, having undifferentiated multipotent polymorph precursors (also referred to herein as polymorph precursors), and treating the carbonate precipitate, which may be a carbonate slurry, under conditions sufficient to produce a building material. The subject methods also include preparing a calcium carbonate material consisting of any or a combination of multipotent polymorph precursors, polymorph precursors, ACC, bartalite, and / or aragonite, and treating the carbonate material via seeding and / or bicarbonate washing in a manner sufficient to produce a building material. In some versions, the carbonate slurry is a slurry of metal carbonate particles (e.g., alkaline earth metal carbonate particles). For example, in some versions, the metal carbonate particles are calcium carbonate particles or calcium magnesium carbonate particles. The polymorph precursors described herein exist in a state between an amorphous state and an ordered state (e.g., amorphous calcium carbonate (ACC) and polymorphs). Thus, in some cases, the polymorphic precursors include vaterite precursors, calcite precursors, aragonite precursors, and / or dolomite precursors. In some embodiments, the method also includes evaluating the carbonate slurry for the presence of polymorphic precursors. Techniques for evaluating the carbonate slurry include, for example, scanning electron microscopy (SEM), X-ray diffraction (XRD), obtaining an infrared (IR) spectrum of the carbonate slurry, and obtaining the Ca:C ratio.

[0009] An embodiment of the invention further comprises contacting the carbonate precipitate, e.g., carbonate slurry (in the form of any of the polymorphic precursors, polymorphic precursors, ACC, vaterite, calcite, and / or aragonite, or combinations thereof, in the case of calcium magnesium carbonate polymorphic precursors, dolomite) with sufficient setting liquid (e.g., carbonate setting liquid, bicarbonate setting liquid, phosphate setting liquid, divalent alkaline earth metal setting liquid, or water) to produce a hardened building material. An embodiment of the invention further comprises incorporating a "seed" of the desired end product with the metal carbonate (any of the polymorphic precursors, polymorphic precursors, ACC, vaterite, calcite, and / or aragonite, or combinations thereof, in the case of calcium magnesium carbonate polymorphic precursors, dolomite) and then "hardening" with moisture. An embodiment of these "seeds" includes aragonite, calcite, or in the case of calcium magnesium carbonate polymorphic precursors, dolomite, or any crystalline metal carbonate particle having the desired end structure. Building materials produced via the subject methods include, for example, aggregates.

[0010] In some embodiments, preparing the carbonate precipitate, e.g., carbonate slurry, comprises a CO2 sequestration process. For example, in certain embodiments, the CO2 sequestration process comprises contacting an aqueous capture liquid with a gaseous CO2 source under conditions sufficient to produce an aqueous carbonate salt. The method may additionally comprise combining a cation source with the aqueous carbonate salt under conditions sufficient to produce a CO2 sequestering carbonate salt. In some cases, the aqueous capture liquid is an aqueous ammonia capture liquid. Aspects of the invention also include building materials (e.g., aggregates) and compositions (e.g., concrete dry composites, settable compositions, and building structures) produced via the subject methods. [Brief description of the drawings]

[0011] The invention can be best understood from the following detailed description when read in conjunction with the accompanying drawing figures, which include: [Figure 1]1 is a flow chart illustrating the production of building materials using a carbonate slurry having undifferentiated pluripotent polymorphic precursors, according to certain embodiments. [Diagram 2] FIG. 13 is a scanning electron microscope (SEM) image of undifferentiated pluripotent polymorphic precursors prepared from the CO2 sequestration process. Note the spherical nature of the material in the image. [Diagram 3] 14A-14C are scanning electron microscope (SEM) images of the building materials processed from the carbonate slurries evaluated. Note the ordered crystalline nature of the materials in the images. [Figure 4-1] FIG. 1 illustrates the use of infrared (IR) spectroscopy to evaluate materials for the presence of polymorphic precursors produced from carbonate slurries prepared via a CO2 sequestration process. Also included in the figure are IR spectra of building materials produced from processing carbonate slurries containing desired differentiated polymorphic precursors, and spectra of building materials produced from processing undesired differentiated polymorphic precursors. Note the phenomenon of undifferentiated pluripotent polymorph (UPP) precursors in the carbonate slurries differentiating into a specific polymorph of calcium carbonate in the building material, namely calcite. [Figure 4-2] Continuing with FIG. 4-1, there is shown the use of infrared (IR) spectroscopy to evaluate materials for the presence of polymorphic precursors produced from carbonate slurries prepared via a CO2 sequestration process. Also included in the figure are IR spectra of building materials produced from processing carbonate slurries containing desired differentiated polymorphic precursors, and spectra of building materials produced from processing undesired differentiated polymorphic precursors. Note the phenomenon of undifferentiated pluripotent polymorph (UPP) precursors in the carbonate slurries differentiating into a specific polymorph of calcium carbonate in the building material, namely calcite. [Diagram 5]Figure 1 illustrates the use of X-ray diffraction (XRD) as a means to evaluate materials for the presence of polymorphic precursors generated from carbonate slurries prepared via a CO2 sequestration process. The weight percentages of different polymorphs present in the materials are based on Rietveld refinement results from the XRD data. The phenomenon of undifferentiated polymorphic precursors in carbonate slurries that differentiate into specific polymorphs of calcium carbonate in building materials, i.e., from amorphous calcium carbonate (ACC) polymorph to vaterite to calcite polymorphs, is eliminated by mineralogical analysis from the XRD data refinement. [Figure 6] In one embodiment, a flow chart illustrating the production of a building material by seeding undesired differentiated polymorphic precursors produced from a carbonate slurry. By seeding the undesired differentiated polymorphic precursors with calcite polymorph and treating the seeded polymorphic precursors with heat and moisture, a continuous phase calcite polymorph suitable for use as a building material can be produced. [Figure 7] FIG. 1 illustrates the use of scanning electron microscopy (SEM) to identify “polymorphic precursors” from a CO2 sequestration process. [Figure 8] FIG. 1 shows the use of XRD to identify polymorphic precursors by broad peaks. [Figure 9] FIG. 1 shows data showing the production of aragonite end-product using aragonite seeds as determined from XRD. [Figure 10] FIG. 1 shows the strength improvement from the same calcium carbonate precipitate when processed in a typical manner compared to when seeds are added to the precipitate. [Figure 11] FIG. 1 shows the demonstration of the presence of different crystal systems of CaCO, including two different crystal systems of vaterite, using the method of X-ray diffraction (XRD). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Methods of producing building materials are provided. The subject methods include preparing a carbonate precipitate, e.g., a carbonate slurry, that includes undifferentiated multipotent polymorphic precursors (also referred to herein as polymorphic precursors), and treating the carbonate slurry under conditions sufficient to produce a building material. The polymorphic precursors exist in an intermediate state between an amorphous state (e.g., amorphous calcium carbonate (ACC)) and an ordered state (e.g., a polymorph of calcium carbonate). Aspects of the invention also include building materials (e.g., aggregates), as well as compositions (e.g., concrete dry composites, settable compositions, and building structures) that include the building materials produced via the subject methods.

[0013] Before the present invention is described in more detail, it is to be understood that the invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0014] Where a range of values ​​is provided, unless the context clearly indicates otherwise, each intervening value will be understood to be included, to one-tenth of the unit of the lower limit, between the upper and lower limit of that range and any other stated or intervening value in that stated range.

[0015] The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the invention, subject to any specific excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

[0016] Certain ranges are presented herein with the term "about" preceding the numerical values. In this specification, the term "about" is used to provide literal support for the exact number it precedes, as well as a number that is close to or approximately the number it precedes. When determining whether a number is close to or approximately a specifically recited number, the close or approximate unrecited number may be a number that, in the context in which it is presented, provides a substantial equivalent to the specifically recited number.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, representative exemplary methods and materials are now described.

[0018] All publications and patents cited herein are incorporated by reference as if each individual publication or patent was specifically and individually indicated to be incorporated by reference, and are incorporated by reference herein to disclose and describe the methods and / or materials in connection with which the publications are cited. The citation of any publication is for its disclosure prior to the date of the present application and should not be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the publication dates provided may be different from the actual publication dates which may need to be independently confirmed.

[0019] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should be further noted that the claims may be drafted to exclude any optional element. Thus, this statement is intended to serve as a predicate for the use of exclusive terminology such as "solely" and "only" in connection with the recitation of claim elements, or for the use of a "negative" limitation.

[0020] As will be apparent to those skilled in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has distinct components and features which may be readily separated from or combined with the features of any of the other embodiments without departing from the scope or spirit of the invention. Any recited method may be carried out in the order of events recited or in any other order which is logically possible.

[0021] How to Produce Building Materials As discussed above, aspects of the present invention include methods of producing building materials. The subject methods include preparing a carbonate precipitate (e.g., in the form of a slurry) that includes undifferentiated multipotent polymorphic precursors (i.e., polymorphic precursors) and treating the carbonate precipitate, e.g., carbonate slurry, under conditions sufficient to produce a building material. As discussed herein, "undifferentiated polymorphic precursors" or "polymorphic precursors" refer to carbonate compounds that exist in a state between an amorphous state and an ordered state.

[0022] Preparation of carbonate slurry via CO2 sequestration process (box 101, Figure 1) results in the generation of undifferentiated pluripotent polymorphic precursors (box 102, Figure 1). That precursor can be manipulated / controlled to create a desired differentiated polymorphic precursor that will form a specific polymorph such as calcite (or any polymorph desired) (box 103, Figure 1). However, undesired differentiated polymorphic precursors may be created that will form an undesired polymorph such as aragonite (or any polymorph undesired) (box 104, Figure 1). In this case, additional processes can be used to manipulate / control the undesired polymorph back to a desired differentiated polymorphic precursor that will form the selected specific polymorph (box 105, Figure 1). In either case, the resulting generated building material, e.g., aggregate for concrete, is used to construct building structures (box 106, Figure 1).

[0023] For example, an undifferentiated polymorph precursor slurry may be produced in a carbon sequestration process and then differentiated to convert to a specific polymorph precursor or to prevent the formation of a specific polymorph precursor. If differentiated polymorph precursors are not desired for the building material, a second method / system (rinsing, curing, chemical additives, seeding, etc.) may be applied to differentiate the polymorph precursor to the desired final polymorph. One embodiment of the method includes contacting the polymorph precursor with magnesium to differentiate the undifferentiated polymorphic precursor to an amorphous polymorph precursor and prevent the formation of calcite as the final polymorph. In an alternative embodiment, the method includes contacting the polymorph precursor with strontium to differentiate the undifferentiated polymorphic precursor to an amorphous polymorph precursor and prevent the formation of aragonite as the final polymorph.

[0024] Undifferentiated pluripotent polymorphic precursor The undifferentiated pluripotent polymorph precursor (i.e., polymorph precursor) used in the embodiments of the present invention may include any suitable one or more carbonate compounds. Different valence cations can form solid carbonate compositions (e.g., in the form of carbonate minerals). In some cases, monovalent cations such as sodium and potassium cations can be present in the carbonate compound of the polymorph precursor. In other cases, divalent cations such as alkaline earth metal cations, e.g., calcium and magnesium cations, can be present. The carbonate compound of the polymorph precursor can be prepared by the molecular formulation X. m (CO3) n where X is any element or combination of elements capable of chemically bonding with a carbonate group or groups, X in certain embodiments is an alkaline earth metal and not an alkali metal, and m and n are stoichiometric positive integers. These carbonate compounds have one or more structural waters in the molecular formula, X m (CO3) n It may have a molecular formula of H2O. In one particular case, the carbonate is calcium carbonate (CaCO3).

[0025] In embodiments of the present invention where the carbonate compound is calcium carbonate, the amorphous state may be amorphous calcium carbonate (ACC) and the ordered state may be a polymorph of calcium carbonate. As understood in the art, ACC describes a state of calcium carbonate that lacks crystalline structure. ACC is a generally transient form of calcium carbonate that converts to a polymorph under certain conditions (e.g., in the presence of water and / or heat). ACC may contain different levels of hydration. In some embodiments, ACC is hydrated (i.e., contains one or more structural waters). In certain cases, hydrated ACC can contain about 1.6 moles of water per mole of calcium carbonate. In other cases, ACC can be anhydrous.

[0026] As discussed herein, a "polymorph" refers to one of a series of crystalline forms that can be derived from an amorphous substance. In other words, a polymorph is a compound that has the same empirical formula but different crystal structures. Polymorphs of interest may include anhydrous polymorphs as well as hydrated polymorphs. For example, the anhydrous phase of calcium carbonate includes calcite (CaCO3), aragonite (CaCO3), and vaterite (CaCO3). The hydrated phase of calcium carbonate includes monohydrocalcite (CaCO3·H2O) and icalite (CaCO3·6H2O). Calcite, aragonite, and betalite are polymorphs of calcium carbonate (CaCO3) because they all have the same empirical formula of CaCO3, but differ from each other in crystal structure, e.g., the crystal structure space groups of calcite and aragonite are R3c and Pmcn, respectively. ACC and calcium carbonate polymorphs are discussed, for example, in Bots et al. Cryst. Growth Des. (2012) 12:1306-1384, and Radha et al. PNAS. (2010) 107:16438-16443, the disclosures of which are incorporated herein by reference in their entireties. In additional cases, the polymorph comprises calcium magnesium carbonate. In such cases, the polymorph may be dolomite or protodolomite.

[0027] Thus, in some cases, the polymorphic precursors of the present invention are calcium carbonate compounds that exist in an intermediate state between ACC and calcium carbonate polymorphs, as shown below. ACC → polymorphic precursor → polymorphic (differentiated type) Polymorphic precursors of interest may include, for example, vaterite precursors, calcite precursors, aragonite precursors, monohydrocalcite precursors, and icarite precursors. In certain cases, the polymorphic precursors are selected from the group consisting of vaterite precursors, calcite precursors, and aragonite precursors. In one embodiment, the polymorphic precursors include vaterite precursors. In another embodiment, the polymorphic precursors include calcite precursors. In yet another embodiment, the polymorphic precursors include aragonite precursors. Other embodiments of the invention may include combinations of polymorphic precursors (e.g., combinations of vaterite precursors, calcite precursors, and aragonite precursors). Another polymorphic precursor of the invention is a calcium magnesium carbonate compound that exists in an intermediate state between ACC and calcium magnesium carbonate polymorphs. Polymorphic precursors of interest may include, for example, dolomite precursors or protodolomite precursors.

[0028] The undifferentiated multipotent polymorphic precursor may include different polymorphic precursors of calcium carbonate, such as amorphous calcium carbonate (ACC), vaterite, aragonite, or calcite precursors, as well as additional components, such as UCA / waste sludge. In some embodiments where the polymorphic precursor is composed of vaterite precursor, the crystal system of the vaterite precursor may be in either the hexagonal, triclinic, monoclinic, or orthorhombic crystal system. For example, in some embodiments, the polymorphic precursor is composed of 16% ACC precursor, 79% vaterite precursor, and 5% calcite precursor, with the 79% vaterite precursor being composed of 30% hexagonal vaterite precursor and 49% triclinic vaterite precursor as determined by XRD (Figure 11).

[0029] The polymorphic precursors discussed herein can be described as predestined with respect to the polymorph they will eventually transform into. By "predestined" we mean that the composition and / or structure of the polymorphic precursor is such that the polymorph it will transform into has already been determined. For example, if ACC produces a vaterite precursor, the vaterite precursor is predestined to form vaterite and only vaterite. In other words, without some other intervention, the vaterite precursor will not become, for example, aragonite or calcite. The same is true for other polymorphic precursors, the aragonite precursor is predestined to become aragonite, and the calcite is predestined to become calcite.

[0030] In some cases, the polymorphic precursors discussed herein are amorphous. By "amorphous" it is meant that the polymorphic precursor is essentially non-crystalline. The amorphous nature of the polymorphic precursor can be observed by a number of suitable techniques. For example, the polymorphic precursor may appear as a globular structure when viewed via a scanning electron microscope (SEM), as opposed to the more ordered structure of the polymorph or crystal, as shown, for example, in FIG. 2. In addition, when analyzed via infrared (IR) spectroscopy and / or X-ray diffraction (XRD), the polymorphic precursor exhibits broad peaks. Furthermore, in some cases, the calcium to carbon ratio (Ca:C) of the carbonate slurry may show a calcium deficiency (i.e., compared to a carbonate slurry in which the polymorphic precursor is absent). Suitable SEM, IR, XRD, and Ca:C protocols are described in detail below.

[0031] In one embodiment, where the carbonate slurry is prepared, for example, via a CO2 sequestration process, the carbonate slurry comprises metal carbonate particles, specifically calcium carbonate particles. The carbonate slurry comprising calcium carbonate particles is evaluated for the presence of undifferentiated multipotent polymorphic precursors by several techniques. Figure 2 illustrates one such technique, namely the use of a scanning electron microscope (SEM), where the image was taken immediately after dehydrating the carbonate slurry of metal carbonate particles, specifically calcium carbonate particles. The spherical nature of the material shown in the SEM image of Figure 2 suggests the presence of undifferentiated multipotent polymorphic precursors that are essentially amorphous. The evaluated carbonate slurry of metal carbonate particles, specifically calcium carbonate particles, was further processed under conditions sufficient to produce an aggregate for a building material, for example, concrete. Here, the carbonate slurries evaluated that showed evidence of undifferentiated pluripotent polymorphic precursors were rinsed with a solution of water and bicarbonate, then agglomerated into larger particles of several millimeters in diameter to form an aggregate building material suitable for, for example, concrete, and finally cured in the bicarbonate solution for 10 days to produce a hardened building material, for example, an aggregate for concrete. An SEM image of the hardened building material produced in this embodiment is shown in FIG. 3. Note the ordered calcite crystal structure observed in this image. This provides an example of the present invention where the presence of undifferentiated pluripotent polymorphic precursors in the carbonate slurry was processed to form differentiated polymorphic precursors that will form the calcite polymorph in the final building material used to construct the building structure.

[0032] In other embodiments where the carbonate slurry is prepared, for example, via a CO2 sequestration process, the carbonate slurry including metal carbonate particles, specifically calcium carbonate particles, is evaluated for the presence of undifferentiated multipotent polymorph precursors by infrared spectroscopy (IR), for example, as shown in the IR spectra in Figures 4-1 and 4-2. The IR spectra serve to show the transition that occurs from the undifferentiated multipotent polymorph precursors to differentiated calcite polymorphs by processing the carbonate slurry with washing and hardening steps to ultimately produce aggregate for a building material, for example, concrete. As shown in Figures 4-1 and 4-2, representative IR spectra of calcium carbonate at different points during processing are presented. From top to bottom, the IR spectra show fresh carbonate slurry, carbonate slurry washed with water, slurry washed with NaHCO3, fresh aggregate, aggregate 7 days after production without processing, aggregate 3 days after hardening, and finished washed / hardened aggregate after 7 days.

[0033] In some embodiments, when a carbonate slurry is prepared, for example, via a CO sequestration process, the carbonate slurry including metal carbonate particles, specifically calcium carbonate particles, is evaluated for the presence of undifferentiated pluripotent polymorphic precursors by X-ray diffraction (XRD). In this embodiment of the method, refinement of the XRD data helps to illustrate the transition that occurs from the undifferentiated pluripotent polymorphic precursors to differentiated calcite polymorphs by treating the carbonate slurry with washing and hardening steps, ultimately producing an aggregate composed of a particular polymorph suitable for use as a building material, for example, the calcite polymorph suitable for concrete.

[0034] In Figure 5, the weight percentages of different polymorphs present in the analyzed materials are based on the Rietveld refinement results from the XRD data. The phenomenon of undifferentiated polymorphic precursors in the carbonate slurry differentiating into specific polymorphs of calcium carbonate in the building materials, i.e., from amorphous calcium carbonate (ACC) polymorph to vaterite to calcite, is shown by the mineralogical analysis from the XRD data refinement. Figure 5 shows, from left to right, fresh carbonate slurry, carbonate slurry washed with water, carbonate slurry washed with NaHCO3, fresh agglomerated aggregate, and hardened aggregate.

[0035] As mentioned above, polymorphic precursors can be described as existing in an intermediate state between ACC and calcium carbonate polymorphs. In other words, polymorphic precursors can adopt characteristics of both ACC and the polymorph that the polymorphic precursor is destined to become. For example, polymorphic precursors can exist as polymorph-specific lattices within a mass (e.g., globules) of ACC. In certain cases, polymorphic precursors can appear amorphous under analytical methods, but nevertheless contain semi-ordered structures therein.

[0036] The carbonate precipitate of the present invention may or may not have impurities, with "impurities" being defined as materials or substances that are not the intended product. When impurities are present, they are carbonate impurities. In other words, the impurities are polymorphs other than the desired polymorph. In the example where the desired polymorph is betalite or aragonite, an impurity that may be present in the composition is calcite. In additional cases, the impurity may be sludge waste (e.g., sludge waste from other industries). However, impurities may be considered insignificant when the precipitated carbonate includes one of the multipotential polymorph precursors, undesired polymorph precursors, desired polymorph precursors, amorphous CaCO3, vaterite, and / or aragonite.

[0037] Preparation of Undifferentiated Polymorph Precursor Compositions As mentioned above, the method of the present invention includes preparing a carbonate precipitate, e.g., a carbonate slurry, that includes a polymorph precursor (also referred to herein as a "polymorph precursor composition"). The polymorph precursor composition produced by the method of the present invention can include a metal carbonate, such as an alkaline earth metal carbonate, e.g., calcium carbonate, magnesium carbonate, etc., where the carbonate is not crystalline. In some cases, the polymorph precursor composition is included in the slurry. In other words, the composition is a liquid composition that includes a precipitate.

[0038] In other embodiments, the carbonate precipitate is dehydrated, e.g., the mechanical water of the composition is removed. In other words, the undifferentiated pluripotent polymorph precursors may be present in a dry composition (e.g., for storage, etc.). In such cases, the dehydration may not remove structural water that may be part of the precipitate. In selected cases, the dehydrated carbonate precipitate may be rehydrated at a later time. In some such cases, the method includes producing a carbonate slurry (e.g., via the methods described below) and drying the carbonate slurry to produce a dehydrated carbonate precipitate. The carbonate slurry may be dehydrated via any convenient protocol, including, but not limited to, centrifugation, heating (e.g., via a rotary dryer), and the like. The dehydrated carbonate precipitate may be considered a storage-stable form of calcium carbonate, which may include polymorph precursors and / or polymorphs, depending on how the precipitate was processed. The method of the present invention may then include rehydrating the dehydrated carbonate precipitate at a later time (e.g., at the point of use).

[0039] The polymorphic precursor composition can be produced using any convenient protocol. In some cases, the polymorphic precursor composition is produced using a CO2 sequestration process. The CO2 sequestration process refers to a process in which a certain amount of gaseous CO2 is converted into a carbonate solution, thereby sequestrating the CO2. A variety of different CO2 sequestration processes can be used to produce the polymorphic precursor composition.

[0040] In some cases, an ammonia-mediated CO sequestration process is used to produce the polymorphic precursor composition. Such method embodiments include multi-step or single-step protocols, as desired. For example, in some embodiments, the combination of a CO capture liquid and a gaseous CO source results in the production of an aqueous carbonate salt, which is then combined with a divalent cation source, e.g., Ca, to produce the polymorphic precursor composition. 2+ And / or Mg 2+ In yet another embodiment, a one-step CO2 gas absorption carbonate precipitation protocol is used.

[0041] The CO2-containing gas may be pure CO2 or may be combined with one or more other gases and / or particulate components depending on the source, e.g., a multi-component gas (i.e., a multi-component gas stream). In certain embodiments, the CO2-containing gas is obtained from an industrial plant, e.g., where the CO2-containing gas is a waste feed from the industrial plant. The industrial plants from which the CO2-containing gas may be obtained, e.g., as a waste feed from the industrial plant, may vary. Industrial plants of interest include, but are not limited to, power plants and industrial product manufacturing plants, e.g., but are not limited to, chemical and mechanical processing plants, refineries, cement plants, steel plants, etc., as well as other industrial plants that generate CO2 as a by-product of fuel combustion or other processing steps (e.g., calcination by cement plants). Waste feeds of interest include, for example, gas streams produced by industrial plants as secondary or incidental products of processes performed by the industrial plants.

[0042] Of interest in certain embodiments are waste streams generated by industrial plants that burn fossil fuels, such as coal, petroleum, natural gas, and engineered fuel products of naturally occurring organic fuel deposits, such as, but not limited to, tar sands, heavy oil, oil shale, etc. In certain embodiments, the power plants are pulverized coal power plants, supercritical coal power plants, bulk-burn coal power plants, fluidized bed coal power plants, gas or oil-fired boiler and steam turbine power plants, gas or oil-fired boiler simple cycle gas turbine power plants, and gas or oil-fired boiler combined cycle gas turbine power plants. Of interest in certain embodiments are waste streams generated by power plants that burn synthesis gas, i.e., gas produced by gasification of organic matter such as coal, biomass, etc., and in certain embodiments, such plants are integrated gasification combined cycle (IGCC) plants. Of interest in certain embodiments are waste streams generated by heat recovery steam generator (HRSG) plants. Waste streams of interest also include waste streams generated by cement plants. Cement plants in which waste streams may be used in the method of the present invention include both wet and dry process plants, which may use blast furnaces or rotary kilns and may include precalciners. Each of these types of industrial plants can burn a single fuel or two or more fuels, either sequentially or simultaneously. The waste stream of interest is industrial plant exhaust gas, e.g., flue gas. By "flue gas" is meant gas obtained from the combustion products of the combustion of fossil or biomass fuels, which are then sent to the stack, also known as the flue of the industrial plant. Each of these industrial plants can burn a single fuel or two or more fuels, either sequentially or simultaneously. Other industrial plants, such as smelters and refineries, are also useful sources of waste streams that contain carbon dioxide.

[0043] Industrial waste gas streams may contain carbon dioxide as the primary non-air derived component, or, particularly in the case of coal-fired power plants, may contain additional components such as nitrogen oxides (NOx), sulfur oxides (SOx), and one or more additional gases (which may be collectively referred to as non-CO2 pollutants). The additional gases and other components may include CO, mercury and other heavy metals, and dust particles (e.g., from calcination and combustion processes). Additional non-CO2 pollutant components in the gas stream also include halides such as hydrogen chloride and hydrogen fluoride; particulate matter such as fly ash, dust, and metals such as arsenic, beryllium, boron, cadmium, chromium, chromium VI, cobalt, lead, manganese, mercury, molybdenum, selenium, strontium, thallium, vanadium; and organics such as hydrocarbons, dioxins, and PAH compounds.Suitable gaseous waste streams that may be treated include, in some embodiments, those having CO2 concentrations of 200 ppm to 1,000,000 ppm, or 200 ppm to 500,000 ppm, or 200 ppm to 100,000 ppm, or 200 ppm to 10,000, or 200 ppm to 5,000 ppm, or 200 ppm to 2000 ppm, or 200 ppm to 1000 ppm, or 200 to 500 ppm, or 500 ppm to 1,000,000 ppm, or 500 ppm to 500,000 ppm, or 500 ppm to 100,000 ppm. ppm, or 500ppm~10,000ppm, or 500ppm~5,000ppm, or 500ppm~2000ppm, or 500ppm~1000ppm, or 1000ppm~1,000,000ppm, or 1000ppm~500,000ppm, or 1000ppm~100,000ppm, or 1000ppm~10,000, or 1000ppm~5,000ppm, or 1000ppm~2000ppm, or 2000ppm~1,000,000ppm, or 2000ppm~500,000 ppm, or 2000ppm to 100,000ppm, or 2000ppm to 10,000, or 2000ppm to 5,000ppm, or 2000ppm to 3000ppm, or 5000ppm to 1,000,000ppm, or 5000ppm to 500,000ppm, or 5000ppm to 100,000ppm, or 5000ppm to 10,000, or 10,000ppm to 1,000,000ppm, or 10,000ppm to 500,000ppm, or 10,000ppm to 100,000ppm, or

[0023] It is present in an amount of from 50,000 ppm to 1,000,000 ppm, or from 50,000 ppm to 500,000 ppm, or from 50,000 ppm to 100,000 ppm, or from 100,000 ppm to 1,000,000 ppm, or from 100,000 ppm to 500,000 ppm, or from 200,000 ppm to 1000 ppm, including from 200,000 ppm to 2000 ppm, for example from 180,000 ppm to 2000 ppm, or from 180,000 ppm to 5000 ppm, including from 180,000 ppm to 10,000 ppm.

[0044] Various waste streams, particularly combustion gases, may contain one or more additional non-CO2 components, such as water, NOx (single nitrogen oxides: NO and NO2), SOx (single sulfur oxides: SO, SO2 and SO3), VOCs (volatile organic compounds), heavy metals such as, but not limited to, mercury, and particulate matter (solid or liquid particles suspended in the gas). Flue gas temperatures may also vary. In some embodiments, the temperature of the flue gas containing CO2 is 0°C to 2000°C, or 0°C to 1000°C, or 0°C to 500°C, or 0°C to 100°C, or 0°C to 50°C, or 10°C to 2000°C, or 10°C to 1000°C, or 10°C to 500°C, or 10°C to 100°C, or 10°C to 50°C, or 50°C to 2000°C, or 50°C to 1000°C, or 50°C to 500°C, or 50°C to 100°C, or 100°C to 2000°C, or 100°C to 1000°C, or 100°C to 500°C, or 500°C to 2000°C, or 500°C to 1000°C, or 500°C to 800°C, or 60°C to 700°C, including 100°C to 400°C.

[0045] Another gas source of CO2 is a direct air capture (DAC) generated gaseous CO2 source. A DAC generated gaseous CO2 source is a product gas generated by a direct air capture (DAC) system. A DAC system is a type of technology that can directly separate carbon dioxide CO2 from ambient air. A DAC system is any system that captures CO2 directly from air and generates a product gas that contains CO2 at a higher concentration than the air input to the DAC system. The concentration of CO2 in a DAC generated gaseous CO2 source can vary, but in some cases the concentration includes 1,000 ppm or more, e.g., 10,000 ppm or more, 100,000 ppm or more, and the product gas may not be pure CO2, and in some cases the product gas is 3% or more non-CO2 constituents, such as 5% or more non-CO2 constituents, including 10% or more non-CO2 constituents. Non-CO2 constituents that may be present in the product stream may be constituents from the input air and / or the DAC system. In some cases, the concentration of CO2 in the DAC product gas ranges from 1,000 to 999,000 ppm, such as from 1,000 to 10,000 ppm, or from 10,000 to 100,000 ppm, or from 100,000 to 999,000 ppm.The gaseous stream generated in the DAC, in some embodiments, has a CO2 concentration of 200 ppm to 1,000,000 ppm, or 200 ppm to 500,000 ppm, or 200 ppm to 100,000 ppm, or 200 ppm to 10,000, or 200 ppm to 5,000 ppm, or 200 ppm to 2000 ppm, or 200 ppm to 1000 ppm, or 200 to 500 ppm, or 500 ppm to 1,000,000 ppm, or 500 ppm to 500,000 ppm, or 500 ppm to 100,0 00ppm, or 500ppm~10,000, or 500ppm~5,000ppm, or 500ppm~2000ppm, or 500ppm~1000ppm, or 1000ppm~1,000,000ppm, or 1000ppm~500,000ppm, or 1000ppm~100,000ppm, or 1000ppm~10,000, or 1000ppm~5,000ppm, or 1000ppm~2000ppm, or 2000ppm~1,000,000ppm, or 2000ppm~500,000ppm pm, or 2000ppm~100,000ppm, or 2000ppm~10,000, or 2000ppm~5,000ppm, or 2000ppm~3000ppm, or 5000ppm~1,000,000ppm, or 5000ppm~500,000ppm, or 5000ppm~100,000ppm, or 5000ppm~10,000, or 10,000ppm~1,000,000ppm, or 10,000ppm~500,000ppm, or 10,000ppm~100,000ppm, or 5

[0023] It is present in an amount of from 0,000 ppm to 1,000,000 ppm, or from 50,000 ppm to 500,000 ppm, or from 50,000 ppm to 100,000 ppm, or from 100,000 ppm to 1,000,000 ppm, or from 100,000 ppm to 500,000 ppm, or from 200,000 ppm to 1000 ppm, including from 200,000 ppm to 2000 ppm, for example from 180,000 ppm to 2000 ppm, or from 180,000 ppm to 5000 ppm, including from 180,000 ppm to 10,000 ppm.

[0046] The DAC product gas that is contacted with the aqueous capture liquid can be produced by any convenient DAC system. A DAC system is a system that extracts CO2 from air using a medium that binds CO2 but not other atmospheric pressure chemicals (such as nitrogen and oxygen). As air passes over the CO2 binding medium, the CO2 "sticks" to the binding medium. The bound CO2 may then be released from the binding medium in response to a stimulus, such as heat, humidity, etc., to produce a gaseous CO2-containing product. DAC systems of interest include, but are not limited to, hydroxide-based systems, CO2 sorbent / temperature swing-based systems, and CO2 sorbent / temperature swing-based systems. In some cases, the DAC system is a hydroxide-based system, and CO2 is separated from air by contacting the air with an aqueous hydroxide liquid. Examples of hydroxide-based DAC systems include, but are not limited to, those described in PCT Publication Nos. 2009 / 155539, 2010 / 022339, 2013 / 036859, and 2013 / 120024, the disclosures of which are incorporated herein by reference. In some cases, the DAC system is a CO2 sorbent-based system, where CO2 is separated from air by contacting the air with a sorbent, such as an amine sorbent, followed by release of the sorbent-captured CO2 by subjecting the sorbent to one or more stimuli, such as a change in temperature, a change in humidity, and the like.Examples of such DAC systems include, but are not limited to, those disclosed in PCT Publication Nos. 2005 / 108297, 2006 / 009600, 2006 / 023743, 2006 / 036396, 2006 / 084008, 2007 / 016271, 2007 / 114991, 2008 / 042919, 2008 / 061210, 2008 / 131132, 2008 / 144708, 2009 / 061836, 200 9 / 067625, 2009 / 105566, 2009 / 149292, 2010 / 019600, 2010 / 022399, 2 010 / 107942, 2011 / 011740, 2011 / 137398, 2012 / 106703, 2013 / 028688, No. 2013 / 075981, No. 2013 / 166432, No. 2014 / 170184, No. 2015 / 103401, No. 2015 / 185434 , No. 2016 / 005226, No. 2016 / 037668, No. 2016 / 162022, No. 2016 / 164563, No. 2016 / 161998, No. 2017 / 184652, and No. 2017 / 009241, the disclosures of which are incorporated herein by reference.

[0047] Further details regarding DAC-generated gaseous CO sources and their use in producing polymorphic precursor compositions are described in PCT Application No. PCT / US2018 / 020527, published as 2018 / 160888, the disclosure of which is incorporated herein by reference.

[0048] As summarized above, the aqueous capture liquid is contacted with the gaseous CO2 source under conditions sufficient to generate aqueous carbonate. The aqueous capture liquid may vary. Examples of aqueous capture liquids include, but are not limited to, fresh water to bicarbonate buffered aqueous media. The bicarbonate buffered aqueous media used in embodiments of the present invention include liquid media in which a bicarbonate buffer is present. The bicarbonate buffered aqueous media may be naturally occurring or artificial media, as appropriate. Naturally occurring bicarbonate buffered aqueous media include, but are not limited to, water obtained from seas, oceans, lakes, swamps, estuaries, endocannabinoid lakes, saline lakes, alkaline lakes, inland seas, and the like. Artificial sources of bicarbonate buffered aqueous media may also vary and may include saltwater produced by water desalination plants, and the like. Further details regarding capture liquids are provided in PCT Publication Nos. 2014 / 039578, 2015 / 134408, and 2016 / 057709, the disclosures of which are incorporated herein by reference.

[0049] In some embodiments, the aqueous captured ammonia is contacted with a gaseous CO2 source under conditions sufficient to produce aqueous ammonium carbonate. The concentration of ammonia in the aqueous captured ammonia can vary, and in some cases, the aqueous captured ammonia has a concentration of 10-10,000 ppm, or 10-1,000 ppm, or 10-5,000 ppm, or 10-8,000 ppm, or 10-10,000 ppm, or 100-100,000 ppm, or 100-10,000 ppm, or 100-50,000 ppm, or 100-80,000 ppm, or 100-100,000 ppm. pm, or 1,000-350,000 ppm, or 1,000-50,000 ppm, or 1,000-80,000 ppm, or 1,000-100,000 ppm, or 1,000-200,000 ppm, or 1,000-350,000 ppm, or 6,000-85,000 ppm, and including 8,000-50,000 ppm. The aqueous captured ammonia may comprise any convenient water. Waters from which the aqueous captured ammonia may be generated include, but are not limited to, fresh water, sea water, salt water, reclaimed or reused water, produced water, and wastewater. The pH of the aqueous captured ammonia may vary in some cases from 9.0 to 13.5, such as from 10.5 to 12.5. Further details regarding aqueous captured ammonia of interest are provided in PCT Publication No. 2017 / 165849, the disclosure of which is incorporated herein by reference.

[0050] For example, as described above, the CO2-containing gas may be contacted with an aqueous capture liquid, such as aqueous capture ammonia, using any convenient protocol. For example, contact protocols of interest include, but are not limited to, direct contact protocols, such as bubbling the gas through a volume of aqueous medium, simultaneous contact protocols, i.e., contact between gas and liquid phases flowing in one direction, countercurrent protocols, i.e., contact between gas and liquid phases flowing in opposite directions, etc. Contact may be accomplished through the use of injectors, bubblers, fluid Venturi reactors, spargers, gas filters, sprays, trays, scrubbers, absorbers, or packed column reactors, etc., as may be convenient. In some cases, the contacting protocol may use a conventional absorber or absorber bubble column, such as those described in U.S. Pat. Nos. 7,854,791, 6,872,240, and 6,616,733, and U.S. Patent Application Publication No. 2012 / 0237420-A1, the disclosures of which are incorporated herein by reference. The process may be a batch or continuous process. In some cases, a regenerative bubble contactor (RFC) may be used to contact the CO2-containing gas with an aqueous capture liquid, such as aqueous capture ammonia. In some such cases, the RFC may use a catalyst (as described elsewhere), such as a catalyst fixed on / inside the interior of the RFC. Further details regarding suitable RFCs are provided in U.S. Pat. No. 9,545,598, the disclosures of which are incorporated herein by reference.

[0051] In some cases, the gaseous CO2 source is contacted with the liquid using a microporous membrane contactor. The microporous membrane contactor of interest includes a microporous membrane present in a suitable housing, the housing including a gas inlet and a liquid inlet, and a gas outlet and a liquid outlet. The contactor is configured so that the gas and the liquid contact opposite sides of the membrane so that molecules can dissolve from the gas into the liquid through the pores of the microporous membrane. The membrane can be configured in any convenient format, and in some cases, the membrane is configured in a hollow fiber format. Hollow fiber membrane reactor formats that can be used include, but are not limited to, those described in U.S. Patent Nos. 7,264,725, 6,872,240, and 5,695,545, the disclosures of which are incorporated herein by reference. In some cases, the microporous hollow fiber membrane contactor used is a hollow fiber membrane contactor, including polypropylene membrane contactors and polyolefin membrane contactors.

[0052] Contact between the capture liquid and the CO2-containing gas occurs under conditions such that a substantial portion of the CO2 present in the CO2-containing gas goes into solution, e.g., produces bicarbonate ions. Substantial portion means 10% or more, e.g., 50% or more, including 80% or more.

[0053] The temperature of the capture liquid in contact with the CO2-containing gas may vary. In some cases, the temperature may range from -1.4 to 100°C, such as from 20 to 80°C, including from 40 to 70°C. In some cases, the temperature may range from -1.4 to 50°C or higher, such as from -1.1 to 45°C or higher. In some cases, lower temperatures are used, such temperatures may range from -1.4 to 4°C, such as from -1.1 to 0°C. In some cases, warmer temperatures are used. For example, in some cases, the temperature of the capture liquid may be 25°C or higher, such as from 30°C or higher, and in some embodiments, may range from 25 to 50°C, such as from 30 to 40°C.

[0054] The CO2-containing gas and capture liquid are contacted at a pressure suitable for producing the desired CO2-charged liquid. In some cases, the pressure of the contacting conditions is selected to provide optimal CO2 absorption, and such pressure may range from 1 atmosphere to 100 atmospheres, such as 1 to 50 atmospheres, such as 20 to 30 atmospheres, or 1 to 10 atmospheres. If the contacting occurs at a location that is naturally at 1 atmosphere, the pressure may be increased to the desired pressure using any convenient protocol. In some cases, the contacting occurs where the optimal pressure exists, for example, at a subsurface location of a body of water such as an ocean or sea.

[0055] In those embodiments in which a gaseous CO2 source is contacted with aqueous captured ammonia, the contacting is performed in a manner sufficient to produce aqueous ammonium carbonate. The aqueous ammonium carbonate may vary, and in some cases, the aqueous ammonium carbonate includes at least one of ammonium carbonate and ammonium bicarbonate, and in some cases, includes both ammonium carbonate and ammonium bicarbonate. Aqueous ammonium bicarbonate can be viewed as a DIC-containing liquid. Thus, in sequestering CO2 in aqueous captured ammonia, the CO2-containing gas may be contacted with the CO2 capture liquid under conditions sufficient to produce dissolved inorganic carbon (DIC) in the CO2 capture liquid, i.e., to produce a DIC-containing liquid. DIC is the sum of the concentrations of inorganic carbon species in solution, as represented by the following formula: DIC=[CO2 * ]+[HCO3 - ]+[CO3 2- ], [CO2 * ] is the sum of the concentrations of carbon dioxide ([CO2]) and carbonic acid ([H2CO3]), and [HCO3 - ] is the bicarbonate concentration (including ammonium bicarbonate) and [CO3 2-] is the carbonate concentration (including ammonium carbonate) in the solution. The DIC of the aqueous medium can vary, and in some cases, can be from 3 ppm to 168,000 ppm of carbon (C), such as from 3 to 1,000 ppm, or from 3 to 100 ppm, or from 3 to 500 ppm, or from 3 to 800 ppm, or from 3 to 1,000 ppm, or from 100 to 10,000 ppm, or from 100 to 1,000 ppm, or from 100 to 5,000 ppm, or from 100 to 8,000 ppm, or from 100 to 1,000 ppm, or from 100 to 2,000 ppm, or from 100 to 3 ...4,000 ppm, or from 100 to 5,000 ppm, or from 100 to 6,000 ppm, or from 100 to 8,000 ppm, or from 100 to 1,000 ppm, or from 100 to 1,000 ppm, or from 100 to 2,000 ppm, or from 100 to 3,000 ppm, or from 100 to 4,000 ppm, or from 100 to 5,000 ppm, or from 100 to 5,000 ppm, or from 100 to 6,000 ppm, or from 100 to 1,000 ppm, or from 100 to 2,000 ppm, or from 100 to The carbon (C) may be 10,000 ppm, or 1,000-50,000 ppm, or 1,000-8,000 ppm, or 1,000-15,000 ppm, or 1,000-30,000 ppm, or 5,000-168,000 ppm, or 5,000-25,000 ppm, or 6,000-65,000 ppm, or the like, including 8,000-95,000 ppm of carbon (C). The amount of CO2 dissolved in the liquid may vary in some cases from 0.05-40 mM, such as 1-35 mM, including 25-30 mM. The pH of the resulting DIC-containing liquid may vary in some cases from 4-12, such as 6-11 and 7-11, including 8-9.5.

[0056] Optionally, the CO2-containing gas is contacted with the capture liquid in the presence of a catalyst (i.e., either a natural heterogeneous or homogeneous absorption catalyst) that mediates the conversion of CO2 to bicarbonate. Of interest as an absorption catalyst are catalysts that increase the rate of production of bicarbonate ions from dissolved CO2 at pH levels ranging from 8 to 10. The magnitude of the rate increase can vary (e.g., compared to a control in which no catalyst is present), and in some cases is 2-fold or more, e.g., 5-fold or more, e.g., 10-fold or more, compared to a suitable control. Further details regarding examples of catalysts suitable for such embodiments can be found in U.S. Pat. No. 9,707,513, the disclosure of which is incorporated herein by reference.

[0057] In some embodiments, the resulting aqueous carbonate is a two-phase liquid that includes droplets of liquid condensed phase (LCP) in a bulk liquid, e.g., bulk solution. "Liquid condensed phase" or "LCP" refers to a phase of liquid solution that includes bicarbonate ions, the concentration of which is higher in the LCP phase than in the surrounding bulk liquid. The LCP droplets are characterized by the presence of a metastable bicarbonate-rich liquid precursor phase in which bicarbonate ions associate to a condensed concentration that exceeds that of the bulk solution and exist in an amorphous solution state. The LCP contains all the compositions found in the bulk solution outside the interface. However, the concentration of bicarbonate ions is higher than in the bulk solution. In situations where LCP droplets are present, the LCP and bulk solution may contain ion pairs and prenucleation clusters (PNCs), respectively. If present, the ions remain in their respective phases for a longer period of time compared to the ion pairs and PNCs in solution. Further details regarding LCP-containing liquids are provided in US patent application Ser. No. 14 / 636,043, the disclosure of which is incorporated herein by reference.

[0058] As outlined above, both multi-step and single-step protocols can be used to generate polymorphic precursor compositions from CO2-containing gas aqueous captured ammonia. For example, in some embodiments, the product aqueous ammonium carbonate is transferred to a CO2-sequestering polymorphic precursor composition generation module, where divalent cations, e.g., Ca, are added to the product aqueous ammonium carbonate. 2+ And / or Mg 2+ is combined with aqueous ammonium carbonate to produce the CO2-sequestering polymorphic precursor composition. In yet other cases, the aqueous trapped ammonia is generated as aqueous ammonium carbonate combines with divalent cations resulting in the production of the CO2-sequestering polymorphic precursor composition, e.g., Ca 2+ And / or Mg 2+ and the like.

[0059] Thus, in some embodiments, after production of an aqueous carbonate salt, such as, for example, aqueous ammonium carbonate, the aqueous carbonate salt is then combined with a cation source, as described above, under conditions sufficient to produce a solid CO2-sequestering carbonate salt. Different valence cations can form solid carbonate compositions (e.g., in the form of carbonate minerals). In some cases, monovalent cations, such as sodium and potassium cations, can be used. In other cases, alkaline earth metal cations, such as calcium (Ca 2+ ) and magnesium (Mg 2+ Divalent cations such as the Ca cation can be used. When cations are added to the carbonate solution, the divalent cation is Ca 2+ Precipitation of carbonate solids, such as amorphous calcium carbonate (CaCO) when containing 0.1 to 0.2 mM sodium hydroxide, can be produced in a stoichiometric ratio of one carbonate species ion per cation.

[0060] In such cases, any convenient cation source may be used. Cation sources of interest include, but are not limited to, saltwater from water treatment facilities such as seawater dehydration plants, brackish water dehydration plants, groundwater recovery facilities, wastewater facilities, blowdown water from facilities with cooling towers, etc., which generate concentrated solution streams with high cation content. Also of interest as cation sources are naturally occurring sources such as, but not limited to, natural salt water and geological seawater, which may have a variety of cation concentrations and may provide a ready source of thiones to trigger the production of carbonate solids from aqueous ammonium carbonate. In some cases, the cation source may be a waste product of another step of the process, for example, a calcium salt (such as CaCl2) generated during the regeneration of ammonia from aqueous ammonium salt.

[0061] In yet other embodiments, the aqueous captured ammonia includes cations, e.g., as described above. The cations may be provided in the aqueous captured ammonia using any convenient protocol. In some cases, the cations present in the aqueous captured ammonia are derived from geomass (e.g., recycled concrete aggregate (RCA)) used to regenerate the aqueous captured ammonia from the aqueous ammonium salt. Additionally and / or alternatively, the cations may be provided by combining a cation source with the aqueous captured ammonia, e.g., as described above.

[0062] After production of an aqueous carbonate salt, such as aqueous ammonium carbonate, for example, the aqueous carbonate salt is combined with a cation source under conditions sufficient to produce a solid CO2-sequestering carbonate salt, as described above. Cations of different valences can form a solid carbonate composition (e.g., in the form of carbonate minerals). In some cases, monovalent cations such as sodium and potassium cations can be used. In other cases, divalent cations such as alkaline earth metal cations, e.g., calcium and magnesium cations, can be used. Transition metals, e.g., Fe, Mn, Cu, and the like, can also be utilized. When cations are added to the aqueous carbonate solution, the divalent cations are preferably selected from the group consisting of sodium, potassium ... 2+ Precipitation of carbonate solids, such as amorphous calcium carbonate when containing cations, can be produced in a stoichiometric ratio of one carbonate species ion per cation.

[0063] As summarized above, the generation of CO2 from aqueous ammonia capture solution and sequestering carbonate from a gaseous CO2 source yields aqueous ammonium salts. The aqueous ammonium salts produced may vary with respect to the nature of the anion of the ammonium salt, and specific ammonium salts that may be present in the aqueous ammonium salts include, but are not limited to, ammonium chloride, ammonium acetate, ammonium sulfate, ammonium nitrate, and the like.

[0064] Some embodiments of the invention further include regenerating aqueous captured ammonia from the aqueous ammonium salt, e.g., as described above. Regenerating aqueous captured ammonia means treating the aqueous ammonium salt in a manner sufficient to generate a quantity of ammonium from the aqueous ammonium salt. The percentage of the input ammonium salt that is converted to ammonia during this regeneration step may vary in some cases from 5 to 80%, such as 15 to 55%, and in some cases from 20 to 80%, such as 35 to 55%.

[0065] Ammonia can be regenerated from the aqueous ammonium salt in this regeneration step using any convenient regeneration protocol. In some cases, a distillation protocol is used. While any convenient distillation protocol may be used, in some embodiments, the distillation protocol used involves heating the aqueous ammonium salt in the presence of an alkaline source, such as geomass, to produce a gaseous ammonia / water product, which may then be condensed to produce liquid aqueous captured ammonia. In some cases, this protocol is carried out continuously in a stepwise process, where heating the aqueous ammonium salt in the presence of an alkaline source is carried out prior to distillation and condensation of the liquid aqueous captured ammonia.

[0066] The source of alkalinity may vary as long as it is sufficient to convert the ammonium in the aqueous ammonium salt to ammonia. Any convenient source of alkalinity may be used. Sources of alkalinity that may be used in this regeneration step include chemical agents. Chemical agents that may be used as an alkalinity source include, but are not limited to, hydroxides, organic bases, superbases, oxides, and carbonates. Hydroxides include chemical species that provide hydroxide anions in solution, including, for example, sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), or magnesium hydroxide (Mg(OH)2). Organic bases are generally carbon-containing molecules that are nitrogenous bases, including primary amines such as methylamine, secondary amines such as diisopropylamine, tertiary amines such as diisopropylethylamine, aromatic amines such as aniline, heteroaromatic compounds such as pyridine, imidazole, and benzimidazole, and various forms thereof. Suitable superbases for use as proton-removing agents include sodium ethoxide, sodium amide (NaNH2), sodium hydride (NaH), butyllithium, lithium diisopropylamide, lithium diethylamide, and lithium bis(trimethylsilyl)amide. For example, calcium oxide (CaO), magnesium oxide (MgO), strontium oxide (SrO), beryllium oxide (BeO), and barium oxide (BaO) are also suitable proton-removing agents that may be used.

[0067] Also of interest as an alkalinity source are silica sources. The silica source may be a composition containing pure silica or silica in combination with other compounds, such as minerals, so long as there is sufficient silica source to impart the desired alkalinity. In some cases, the silica source is a naturally occurring silica source. Naturally occurring silica sources include silica-containing rocks, which may be in the form of sand or larger rocks. When the raw material is a larger rock, in some cases the rock has been broken down to reduce its size and increase its surface area. Of interest are silica sources comprised of components having a longest dimension ranging from 0.01 mm to 1 meter, such as 0.1 mm to 500 cm, including 1 mm to 100 cm, for example 1 mm to 50 cm. The silica source may be surface treated to increase the surface area of ​​the source, if desired. A variety of different naturally occurring silica sources may be used. Naturally occurring silica sources of interest include, but are not limited to, ultra-soft rocks such as komatite, picritic basalt, kimberlite, lamproite, peridotite, etc., porous rocks such as basalt, diabase (dolerite), and gabbro, intermediate rocks such as andesite and dielite, intermediate felsic rocks such as dacite and granodilite, and felsic rocks such as rhyolite, aplite-pegmatite, and granite. Also of interest are artificial sources of silica. Artificial sources of silica include, but are not limited to, waste streams such as mining wastes; fossil fuel combustion ash; slags, such as iron and steel slags, phosphorus slags; cement ceramic wastes; oil refinery / petrochemical refinery wastes, such as oilfield and methane seam brines; coal seam wastes, such as production brines and coal seam brines; paper processing wastes; water softeners, such as ion exchange waste seawater; silicon processing wastes; agricultural wastes; metal finishing wastes; high pH textile wastes; and caustic sludge. Mining wastes include wastes from the extraction of metals or other valuable or useful minerals from the earth. Wastes of interest include wastes from mines used to raise the pH. This includes red mud from the Bayer aluminum extraction process, wastes from magnesium extraction for seawater, such as at Moss Landing, California, and wastes from other mining processes involving leaching.Ash from the combustion process of fossil fuels, such as coal-fired power plants, often produces ash rich in silica. In some embodiments, ash from the combustion of fossil fuels, such as coal-fired power plants, is provided as a silica source, including fly ash, such as chimney ash, and bottom ash. Additional details regarding silica sources and their uses are described in U.S. Patent No. 9,714,406, the disclosure of which is incorporated herein by reference.

[0068] In an embodiment of the present invention, ash is used as an alkalinity source. In a particular embodiment, the subject is the use of coal ash as ash. Coal ash as used in the present invention refers to the residue generated from the combustion of pulverized anthracite, lignite, asphalt or subbituminous coal in power plant boilers or coal-fired furnaces, such as chain grate boilers, cyclone boilers and fluidized bed boilers. Such coal ash includes fly ash, which is finely divided coal ash carried from the furnace by the exhaust gas or flue gas, and bottom ash, which collects at the base of the furnace as agglomerates.

[0069] Fly ash is generally very heterogeneous, containing a mixture of glass particles with various identifiable crystalline phases such as quartz, malite, and various iron oxides. Fly ashes of interest include Type F and Type C fly ashes. The above types F and C fly ashes are defined in the above CSA Standards A23.5 and ASTM C618. The main differences between these classes are the amount of calcium, silica, alumina, and iron in the ash. The chemistry of the fly ash is largely influenced by the chemical content of the coal burned (i.e., anthracite, asphalt, and lignite). Fly ashes of interest contain significant amounts of silica (silicon dioxide, SiO2) (both amorphous and crystalline) and lime (calcium oxide, CaO, magnesium oxide, MgO).

[0070] Burning harder, older anthracite and bituminous coals typically produces Class F fly ash. Class F fly ash is pozzolanic in nature and contains less than 10% lime (CaO). Fly ash produced from burning younger lignitic or subbituminous coals has some self-cementing properties in addition to being pozzolanic. In the presence of water, Class C fly ash hardens and gains strength over time. Class C fly ash generally contains more than 20% lime (CaO). It is rich in alkali and sulfates (SO4 2- ) is generally higher in Class C fly ash. In some embodiments, it is of interest to use Class C fly ash to generate ammonia from aqueous ammonium salts. For example, as described above, it is intended to extract amounts of constituents present in Class C fly ash to generate a fly ash with properties closer to Class F fly ash, e.g., extract 95% of the CaO in a Class C fly ash having 20% ​​CaO. Thus, a refurbished fly ash material having 1% CaO is obtained.

[0071] The fly ash material solidifies while suspended in the flue gas and is collected using various approaches, for example, by electrostatic precipitation or filter bags. Because the particles solidify while suspended in the flue gas, the fly ash particles are typically spherical and range in size from 0.5 μm to 100 μm. Fly ashes of interest include those containing at least about 80% by weight of particles smaller than 45 microns. In certain embodiments of the present invention, the use of highly alkaline fluidized bed combustor (FBC) fly ash is also of interest.

[0072] Also of interest in embodiments of the present invention are uses of bottom ash. Bottom ash is formed as agglomerates in a coal-fired boiler from the combustion of coal. Such a combustion boiler can be a wet bottom boiler or a dry bottom boiler. When produced in a wet or dry bottom boiler, the bottom ash is quenched with water. Quenching results in agglomerates with a size of 90% falling within the particle size range of 0.1 mm to 20 mm, and the bottom ash agglomerates have a wide distribution of agglomerate sizes within this range. The main chemical components of bottom ash are Fe, Ca, Mg, Mn, Na, and K, as well as silica and alumina with smaller amounts of oxides of sulfur and carbon.

[0073] In certain embodiments, also of interest is the use of volcanic ash as ash, which is composed of small tephra particles less than 2 millimeters in diameter, i.e., crushed rock and glass created by volcanic eruptions.

[0074] In one embodiment of the invention, cement kiln dust (CKD) is used as an alkalinity source. The nature of the fuel from which the ash and / or CKD is generated, and the means of combustion of said fuel, will affect the chemical composition of the resulting ash and / or CKD. Thus, the ash and / or CKD may be used as part of the means to adjust the pH, and based on the chemical composition of the ash and / or CKD, various other components may be utilized with the particular ash and / or CKD.

[0075] In certain embodiments of the present invention, slag is used as an alkalinity source. Slag can be used as the sole pH adjuster or in combination with one or more additional pH adjusters, such as ash. Slag originates from metal processing and can contain calcium and magnesium oxides, as well as iron, silicon and aluminum compounds. In certain embodiments, using slag as a pH adjuster material provides additional benefits through the introduction of reactive silicon and alumina into the precipitation product. Slags of interest include, but are not limited to, blast furnace slag from iron smelting, slag from electric arc or blast furnace processing of iron and / or steel, copper slag, nickel slag, and phosphorus slag.

[0076] As noted above, ash (or slag in certain embodiments) is used in certain embodiments as the sole method of adjusting the pH of the water to a desired level, in yet other embodiments, one or more additional pH adjustment protocols are combined with the use of ash.

[0077] In certain embodiments, also of interest is the use of other waste materials as an alkaline source, such as crushed or demolished, or recycled or returned concrete or mortar. When used, concrete dissolves the discarded sand and aggregates, which can be recycled into the carbonate-producing portion of the process, if desired. The use of demolished and / or recycled concrete or mortar is described further below.

[0078] In certain embodiments, it is the mineral alkalinity source that is of interest. In such cases, the mineral alkalinity source that is contacted with the aqueous ammonium salt may vary and may include, but is not limited to, silicates, carbonates, fly ash, slag, lime, cement kiln dust, etc., as described above. In some cases, the mineral alkalinity source includes rock, for example, as described above.

[0079] In these embodiments, the temperature to which the aqueous ammonium salt is heated can vary, but in some cases the temperature ranges from 25 to 200° C., such as from 25 to 185° C. The heat used to provide the desired temperature may be obtained from any convenient source, including steam, waste heat sources, e.g., flue gas waste heat, and the like.

[0080] The distillation may be carried out at any pressure. When the distillation is carried out at atmospheric pressure, the temperature at which the distillation is carried out may vary in some cases from 50 to 120°C, such as 60 to 100°C, such as 70 to 90°C. In some cases, the distillation is carried out at subatmospheric pressure. The pressure in such embodiments may vary, but in some cases the subatmospheric pressure is in the range of 1 to 14 psig, such as 2 to 6 psig. When the distillation is carried out at subatmospheric pressure, the distillation may be carried out at a lower temperature compared to embodiments carried out at atmospheric pressure. The temperature may vary as desired in such cases, but in some embodiments where subatmospheric pressure is used, the temperature is in the range of 15 to 60°C, such as 25 to 50°C. In the subatmospheric pressure embodiments, the focus is on the use of waste heat for some (if not all) of the heat used during the distillation. Waste heat sources that may be used in such cases include, but are not limited to, flue gas, process steam condensate, heat of absorption generated by CO2 capture and the resulting ammonium carbonate product; and cooling liquids (e.g., from co-located sources of CO2-containing gases such as power plants, factories, etc., as described above), and combinations thereof.

[0081] Aqueous captured ammonia regeneration can also be achieved using an electrolysis-mediated protocol, in which direct current is introduced into the aqueous ammonium salt to regenerate ammonia.Any convenient electrolysis protocol can be used.An example of an electrolysis protocol that can be adapted to regenerate ammonia from aqueous ammonium salt may use one or more elements from the electrolysis system described in U.S. Patent Nos. 7,727,374 and 8,227,127, and published PCT Application Publication No. 2008 / 018928, the disclosures of which are incorporated herein by reference.

[0082] In some cases, the aqueous captured ammonia is regenerated from the aqueous ammonium salt without the input of energy, e.g., in the form of heat and / or electric current, as described above. In such cases, the aqueous ammonium salt is combined with a source of alkalinity in a manner sufficient to produce regenerated aqueous captured ammonia. The resulting aqueous captured ammonia is then not purified by the input of energy, e.g., via a stripping protocol or the like.

[0083] The resulting regenerated aqueous captured ammonia may vary depending, for example, on the particular regeneration protocol used. In some cases, the regenerated aqueous captured ammonia includes ammonia (NH3) at a concentration ranging from 0.1 to 25 moles (M) per liter, e.g., 4 to 20 M (including 12.0 to 16.0 M), as well as any of the ranges provided for the aqueous captured ammonia provided above. The pH of the aqueous captured ammonia may vary, in some cases, from 10.0 to 13.0, such as 10.0 to 12.5. In some cases, for example, when the aqueous captured ammonia is regenerated in a geomass-mediated protocol that does not include an energy input, as described above, the regenerated aqueous captured ammonia may include cations, e.g., Ca. 2+ In addition, the regenerated aqueous captured ammonia may further include an amount of an ammonium salt. In some cases, the ammonia (NH3) is present at a concentration ranging from 0.05 to 4 moles per liter (M), such as from 0.05 to 1M, including from 0.1 to 2M. The pH of the aqueous captured ammonia may in some cases vary from 8.0 to 11.0, such as from 8.0 to 10.0. The aqueous captured ammonia may further include an amount of an ammonium salt, such as from 0.1 to 5 moles per liter (M), such as from 0.1 to 2M, including from 0.5 to 3M. + ), divalent cations, e.g., calcium (Ca) at concentrations ranging from 0.05 to 2 moles (M) per liter, 0.1 to 1M, etc., including 0.2 to 1M. 2+), divalent cations, such as magnesium (Mg) at concentrations ranging from 0.005 to 1 molar (M) per liter, 0.005 to 0.1 M, including 0.01 to 0.5 M 2+ ), divalent anions, such as sulfate (SO4 2- ), which may further include

[0084] An embodiment of the method further includes contacting the regenerated aqueous captured ammonia with a gaseous CO2 source under conditions sufficient to produce a CO2 sequestering carbonate, for example, as described above. In other words, the method includes recycling the regenerated ammonia into the process. In such cases, the regenerated aqueous captured ammonia may be used as the sole capture liquid or may be combined with another liquid, e.g., makeup water, to produce aqueous captured ammonia suitable for use as a CO2 capture liquid. When the regenerated aqueous ammonia is combined with additional water, any convenient water may be used. Waters from which the aqueous captured ammonia may be produced include, but are not limited to, freshwater, seawater, saltwater, produced water, and wastewater.

[0085] In some embodiments, additives are present in the aqueous ammonia capture solution regenerated from a cation source and / or an aqueous ammonium salt solution. Examples of additives include magnesium (Mg 2+ ), Strontium (Sr 2+ ), Barium (Ba 2+ ), radium (Ra 2+ ), Ammonium (NH4 + ), sulfate (SO4 2- ), phosphate (PO4 3- , HPO4 2- , or H2PO4 - ), ionic species such as carboxylate groups such as oxylates, e.g., HNCOO -and carbamate groups such as manganese (Mn), copper (Cu), nickel (Ni), zinc (Zn), cadmium (Cd), chromium (Cr), and other transition metal cations. In some cases, the additives are intentionally added to the cation source and / or the ammonia water capture liquid regenerated from the ammonium water salt. In other cases, the additives are extracted from the alkaline source during some embodiments of the method.

[0086] Evaluation of polymorphic precursor composition In some embodiments, the method also includes evaluating the carbonate precipitate (e.g., carbonate slurry) for the presence of polymorphic precursors. "Evaluating" the carbonate slurry means evaluating whether there is an amount of polymorphic precursor (e.g., calcite precursor, aragonite precursor, vaterite precursor) present in a given carbonate slurry. Any suitable technique may be used to evaluate the carbonate slurry for the presence of polymorphic precursors. In some cases, evaluating the carbonate slurry for the presence of polymorphic precursors includes assaying the carbonate slurry by SEM. As known in the art, SEM produces an image of the sample by scanning the surface of the sample with an electron beam. These electrons interact with the sample and produce a signal that can be analyzed. For example, electrons emitted by the sample after being scanned by the electron beam may be detected to produce an image and derive information about the sample topography. In some cases, evaluating the carbonate slurry for the presence of polymorphic precursors includes evaluating whether the carbonate slurry contains a smooth globular structure. By "smooth" it is meant that the polymorphic precursor structures have a continuous uniform surface (i.e., they do not have altered surface topography). By "spherical" it is meant that the polymorphic precursor structures are substantially (i.e., more or less) spherical. The smooth spherical structures identified via SEM can range in diameter from, for example, 0.001 μm to 50 μm. Any suitable scanning electron microscope may be used to evaluate the carbonate slurry (see, for example, FIG. 2 and the corresponding description above). In some cases, a benchtop scanning electron microscope may be used. Exemplary benchtop scanning electron microscopes are those manufactured by Hitachi, such as the Hitachi TM-3030 and Hitachi TM-4000II benchtop models. Any suitable scanning electron microscope protocol may be used. For example, obtaining SEM images from calcium carbonate particles is described in Kirboga and Oner. Chemical Engineering Transactions. (2013) 32:2119-2124, which is incorporated herein by reference in its entirety.In some embodiments where the carbonate slurry contains a smooth spherical structure, it can be reasonably concluded that one or more types of polymorphic precursors are present within the slurry.

[0087] Figure 7 shows the use of scanning electron microscopy (SEM) to identify polymorphic precursors from the CO2 sequestration process. The spherical morphology of the material in the image indicates the presence of polymorphic precursors.

[0088] In additional cases, evaluating the carbonate slurry for the presence of polymorphic precursors involves obtaining an IR spectrum of the carbonate slurry. As known in the art, infrared spectroscopy involves irradiating samples with infrared light and is used to identify samples and their constituent functional groups. In some cases, evaluating the carbonate slurry for the presence of polymorphic precursors involves Fourier transform infrared spectroscopy (FTIR). FTIR collects spectral data over a wide spectral range, as opposed to dispersive spectrometers, which collect data from a narrow wavelength range at a given time. An IR spectrum plots infrared light absorbance on the vertical axis against frequency or wavelength on the horizontal axis. A characteristic peak for polymorphic precursors occurs at approximately 700 cm. -1 , 710cm -1 , 745cm -1 , and 875 cm -1 In some embodiments, aspects of the invention may also include evaluating whether the IR spectrum exhibits a broad peak. A "broad peak" is one that is greater than or equal to about 700 cm. -1 , 710cm -1 , 745cm -1 , and 875 cm -1It means that the band of is broad. If the polymorphic precursor composition contains a broad peak in the IR spectrum, it can be reasonably concluded that one or more types of polymorphic precursors are present in the slurry. The IR spectrum disclosed herein can be generated via any suitable protocol. Obtaining the IR spectrum of calcium carbonate compositions is described, for example, in U.S. Patent Application Publication No. 2020 / 0129916, and Andersen and Brecevic.Acta Chemica Standinavica.(1991)45:1018-1024, the disclosures of which are incorporated herein by reference.

[0089] In a further embodiment, evaluating the carbonate slurry for the presence of polymorphic precursors includes obtaining an XRD spectrum. As known in the art, X-ray diffraction operates by directing an X-ray beam at a sample and measuring the resulting diffraction pattern as a function of the power direction. The diffraction pattern contains information about how the atoms are arranged in the material. Amorphous materials do not have long-range atomic order. Therefore, X-ray diffraction performed on a carbonate slurry having polymorphic precursors is expected to have one or more broad (i.e., broad) scattering peaks. Thus, if the XRD spectrum obtained for the carbonate slurry has broad peaks, it can be reasonably concluded that the carbonate slurry contains polymorphic precursors. Any suitable XRD protocol for analyzing calcium carbonate compounds can be used. For example, obtaining an XRD spectrum is described in Ni and Ratner. Surf Interface Anal. (2008) 40(10): 1356-1361, which is incorporated herein by reference in its entirety.

[0090] FIG. 8 illustrates the use of XRD to identify polymorphic precursors with carbonate slurries, as evidenced by broad peaks. The figure shows the XRD pattern of a sample where the predominant phase present in the carbonate slurry is the vaterite polymorphic precursor. Here, the peaks match the 2θ reference pattern for vaterite, and the peaks seen are broad compared to those from crystalline material, indicating a vaterite-polymorphic-precursor. The vaterite polymorphic precursor is in a state between the amorphous state and the crystalline vaterite state.

[0091] In further cases, evaluating the carbonate slurry for the presence of polymorphic precursors includes obtaining the Ca:C ratio of the carbonate slurry or its components. Any suitable method for determining the calcium to carbon ratio may be used. In some embodiments, mass spectrometry is applied to determine the calcium to carbon ratio. Any suitable mass spectrometry protocol may be used. For example, in certain cases, time-of-flight secondary ion mass spectrometry (ToF-SIMS) is used. As known in the art, ToF-SIMS is an analytical method that uses a pulsed ion beam to remove molecules from a sample. The mass is determined by measuring the time it takes the removed molecules to reach a detector. ToF-SIMS protocols for analyzing calcium carbonate compounds are described, for example, in Ni and Ratner. Surf Interface Anal. (2008) 40(10): 1356-1361, which is incorporated herein by reference in its entirety. In some cases, evaluating the carbonate slurry for the presence of polymorphic precursors includes evaluating whether the Ca:C ratio indicates Ca deficiency. If the components of the carbonate slurry contain a Ca deficiency, then it can be reasonably concluded that those components contain one or more types of polymorphic precursors. In other embodiments, evaluating the carbonate slurry for the presence of undifferentiated pluripotent polymorphic precursors can be done by, for example, detecting calcium (Ca) by ion chromatography. 2+The method includes using a combination of a method for the analysis of Ca:C with a method for the analysis of inorganic carbon, for example by CO coulometry. The Ca:C ratio can then be determined from the molar ratios measured from each method. The implication of the Ca:C ratio is that in undifferentiated pluripotent polymorphic precursors the ratio should be less than 1, e.g., each Ca 2+ The ions are two HCO3 - ions, with a Ca:C ratio of 0.5. When the transition to the desired differentiated polymorphic precursors occurs, ultimately resulting in a particular CaCO3 polymorph suitable for use as a building material, the Ca:C ratio will be 1, as in the embodiment producing, for example, the calcite polymorph. The precursor phases range from 0-100% amorphous CaCO3 (ACC), 0-100% vaterite. Ca deficiency can occur when Ca is less than 40% by weight of the total CaCO3. With respect to the Ca:C ratio, calcium less than 1:1 can be considered "Ca deficient."

[0092] FIG. 5 illustrates the amount of undifferentiated polymorphic precursors present in a carbonate slurry as determined by refinement of the XRD data. In this case, the carbonate slurry contains 60-70 wt.% amorphous calcium carbonate (ACC) polymorphic precursor, and 30-40 wt.% vaterite polymorphic precursor. After washing the same carbonate slurry with water, the ratio of polymorphic precursors changes until there is approximately the same wt.% of both ACC and vaterite polymorphic precursors. Washing the same carbonate slurry a second time with bicarbonate solution shifts it to 30-40 wt.% ACC polymorphic precursor and 60-70 wt.% vaterite polymorphic precursor. This processing step of washing with water and then bicarbonate solution results in the production of the desired differentiated polymorphic precursors that will form a particular polymorph, for example as illustrated in box 103 of FIG. 1. In this embodiment, the particular polymorph is calcite as shown by the building material set point in FIG. 5, whereby the weight percentage of the building material is >95% by weight of the calcite polymorph and <5% by weight of the vaterite polymorph precursor.

[0093] In some embodiments, evaluating the carbonate slurry includes determining which crystal systems are present in the carbonate slurry. As mentioned above, when the polymorphic precursor is composed of a vaterite precursor, the crystal system of the vaterite precursor can be present in any of the hexagonal, triclinic, monoclinic, or orthorhombic crystal systems. Thus, some methods of the present invention include determining whether the carbonate precipitate (e.g., in the form of a calcium carbonate slurry) includes a hexagonal, triclinic, monoclinic, or orthorhombic crystal system, or some combination thereof. Any suitable determination method may be used. In some cases, the method includes determining the structure of the vaterite precursor using X-ray diffraction. For example, FIG. 11 illustrates how a calcium carbonate composition can include different crystal systems of vaterite precursor and other precursors. As shown in FIG. 11, a given composition of CaCO3 can include several crystal systems (e.g., vaterite-hexagonal, vaterite-triclinic).

[0094] Building material generation As mentioned above, the methods of the present invention include producing a building material. As discussed herein, "building material" refers to a material that can be used in the construction of a building structure. Building materials of interest include, for example, aggregates. In certain cases, the methods include mineralizing carbon from a polymorphic precursor composition to produce a building material. By "mineralizing" is meant that carbon (e.g., in the form of CO2) is encapsulated in a solid composition (e.g., CO2-encapsulated cement or CO2-encapsulated aggregate, etc.).

[0095] In certain cases, the building material is or includes aggregate. The term "aggregate" is used in its conventional sense to refer to a granular material, i.e., a material consisting of particles or particles. Because the aggregate is a carbonate aggregate, the particles of the granular material include one or more carbonate compounds, and the carbonate compound components may be combined with other substances (e.g., substrates) as needed or may comprise the entire particle. In certain cases, the method of the present invention includes producing a carbonate-coated aggregate, for use in, for example, concrete and other applications. The carbonate-coated aggregate may be a conventional or lightweight aggregate. The CO2-sequestering aggregate composition includes aggregate particles having a core and a CO2-sequestering carbonate coating on at least a portion of the surface of the core. The CO2-sequestering carbonate coating is made from a CO2-sequestering carbonate material.

[0096] In some embodiments, the production of building materials involves the use of aggregate substrates. The aggregate substrates can be coated with CO2-sequestering metal carbonates to form coated aggregates. When used, any convenient aggregate substrate can be used. Examples of suitable aggregate substrates include, but are not limited to, natural mineral aggregate materials, such as rock, sand (e.g., natural silica sand), sandstone, gravel, granite, disincatenate, gabbro, basalt, and the like; and synthetic aggregate materials, such as industrial by-product aggregate materials, such as blast furnace slag, fly ash, municipal waste, and recycled concrete. In these cases, the aggregate substrate comprises a material different from the particles of the polymorphous precursor composition.

[0097] In other cases, the substrate may be aggregate formed from the processes described herein from a previous production. In some cases, the substrate may be an aggregate of non-carbonate particles that have been aggregated together with carbonate slurry in a previous production cycle, especially when finer core substrate particles are used. Such aggregated composite substrates may have certain advantages, such as having lightweight properties, imparting properties to the final aggregate that are suitable for lightweight concrete, or having a greater proportion of aggregate that contains CO2-sequestering carbonates, increasing the CO2 sequestration potential of the aggregate when deployed in concrete, thus lowering the embodied CO2 of the concrete in a life cycle analysis.

[0098] When precipitated calcium carbonate is mixed with the aggregate substrate in the rotating drum, the resulting carbonate aggregate is a carbonate-coated aggregate, in which the aggregate particle members include a core material that is at least partially, if not completely, coated with carbonate material. In some cases, especially with finer core particles, the carbonate slurry bonds multiple particles of the core material together into a cohesive composite.

[0099] In some embodiments, the carbonate slurry including the polymorphic precursor is introduced into a rotating drum and subjected to a tumbling action (e.g., mixing) in the rotating drum under conditions sufficient to produce a carbonate aggregate. Methods of producing aggregates including subjecting a carbonate slurry to a tumbling action are described, for example, in U.S. Patent Application No. 17 / 297,278 (published as US2021-0403336 A1), the disclosure of which is incorporated herein by reference. In some cases, the polymorphic precursor composition is introduced into the rotating drum with an aggregate substrate and then mixed in the rotating drum to produce a carbonate-coated aggregate. In some cases, the slurry (and substrate) is introduced into the rotating drum and mixing begins immediately after production of the polymorphic precursor composition, for example, within 12 hours, for example, within 6 hours, and such as within 4 hours of preparing the polymorphic precursor composition. In some cases, the entire process (i.e., from the start of polymorphic precursor composition preparation to obtaining the carbonate aggregate product) is carried out in 15 hours or less, such as 10 hours or less, including 5 hours or less, such as 3 hours or less, including 1 hour or less. The polymorphic precursor composition, and, if present, the aggregate base material, are mixed in the rotating drum for a period of time sufficient to produce the desired carbonate aggregate, which period can vary, but in some cases the period ranges from 10 minutes to 5 hours, such as 15 minutes to 3 hours or more.

[0100] During and / or after mixing, the resulting carbonate aggregate may be dried. If desired, drying may be accomplished using any convenient protocol. In some cases, drying of the resulting carbonate aggregate may occur during production, e.g., by applying heat during mixing. Such protocols include, for example, direct heating of the mixing vessel, e.g., using waste energy to provide heat, or heating the interior of the mixing vessel, e.g., with hot exhaust gases from a fossil fuel combustion process, such that the temperature of the internal atmosphere in which the carbonate aggregate is being produced is between 15°C and 260°C, or between 15°C and 30°C, or between 15°C and 50°C, or between 15°C and 200°C, or between 20°C and 200°C, e.g., between 20°C and 60°C, or between 25°C and 75°C, or between 25°C and 150°C, or between 30°C and 250°C, e.g., between 30°C and 150°C, or between 30°C and 200°C, including between 40°C and 250°C, to dry the carbonate aggregate. In other cases, drying of the resulting carbonate aggregate may occur after production, for example after the aggregate has left the mixing and / or aggregate production vessel. Convenient protocols include drying the resulting carbonate aggregate in the open at ambient conditions, for example outside an aggregate storage bay and / or silo at the production plant, or for example in a covered dome or enclosed container away from the outside elements. In some cases of embodiments, the drying method may include hardening the resulting aggregate, for example as described below.

[0101] In some cases, the method includes combining the carbonate precipitate with a seed structure. The seed structure may be used in certain cases where it is desirable to affect the structure of the carbonate precipitate to obtain a particular result. For example, precipitated CaCO3 may be mixed with a seed of a desired structure of CaCO3 to form a suitable end product, including aggregates and / or building products. In other words, the carbonate precipitate may adopt the structure of the seed. The seed structure may be a crystalline seed structure. In such cases, the carbonate precipitate may adopt the crystalline structure and / or nano / micro structure of the crystalline seed structure. In some cases, the crystalline seed structure may be any desired crystalline form of CaCO3. The crystalline seed structure may include, but is not limited to, calcite, aragonite, and vaterite.

[0102] In one embodiment of the invention, the carbonate precipitate and seeds are combined and then cured (or hardened) to produce a strong building product. In such a case, the calcium carbonate precipitate must contain at least one of the following: amorphous calcium carbonate, multipotent polymorph precursor, desirable polymorph precursor, undesirable polymorph precursor, prevaterite polymorph precursor, vaterite, and / or aragonite. The calcium carbonate precipitate can be any combination or mixture of the above and can include calcite if it also contains at least one of the above. The seeds can be crystalline calcium carbonate of the desired crystal structure and / or nano / micro structure. The calcium carbonate precipitate and seeds are then formed into aggregates by agglomeration in one example. The aggregates are then cured to strengthen them into a strong building material end product.

[0103] The seeds may be added at any stage before hardening. For example, the seeds may be added to the aqueous capture liquid before or after the calcium carbonate precipitate forms or precipitates, to the precipitate-liquid mixture, to the filtration, during the filtration, after the filtration, to the slurry, to the agglomeration drum or mold. The seeds may be mixed or unmixed. The seeds may be sprinkled on the liquid or slurry or powder or solid. For example, if a calcite building product is desired, calcite seeds may be used. If an aragonite building product is desired, aragonite-containing seeds are used. If vaterite is desired, aragonite seeds are used.

[0104] The seeds may vary in particle size, for example from 10 nm to 5 cm, with a typical particle size range of 5 um to 5000 um. In some cases, the seeds may be finished produced building products as described elsewhere herein, which are ground to a desired particle size and either returned to the liquid prior to calcium carbonate precipitation or incorporated in the calcium carbonate precipitation as seeds in a desired proportion. This circular process of incorporating produced products as seeds allows for a zero additive process that may have beneficial cost, supply chain, and CO2 footprint impacts. In one embodiment of the present invention, the seeds may be naturally occurring carbonates (see below).

[0105] The calcium carbonate and seeds are then formed into the desired shape and particle size, for example, as described in U.S. Patent Application Publication Nos. 2015 / 0246314, 2016 / 0121298, 2021 / 0403336, 2021 / 0262320, 2020 / 0129916, and WO 2022 / 140260, the disclosures of which are incorporated herein by reference in their entirety. After the aggregates are formed into the desired shape and particle size, the aggregates (calcium carbonate precipitates and seeds) are cured to harden them into a strong building material until they reach their maximum strength. In embodiments, curing involves maintaining the moisture level in the carbonate precipitate composition. Some embodiments of curing include keeping the composition in a closed or moist environment, such as a bag, bucket, pile of wet product, or humidity chamber. Curing may also include spraying, steaming, or immersing the product in a curing liquid (including water). Optionally, the temperature may be controlled during curing. The temperature may optionally be selected based on the desired final product polymorph.

[0106] In some cases, the seed structures may be aragonite and / or calcite. In some cases, the seed structures may be vaterite, where vaterite is the desired product. In some cases, the seed structures may be dolomite, for example, where the carbonate slurry contains calcium magnesium carbonate particles. In some cases, the seeds are solid rocks that have been crushed to smaller particle sizes. In some cases, the seed structures may be recycled products from the process (a "circulating" process). In other words, products or by-products of the subject methods may be used as the subject seed structures.

[0107] In some cases, the seed structure may be or include a naturally occurring rock or mineral. Examples include, but are not limited to, natural mineral aggregate materials, such as rock, sand (e.g., natural silica sand), dolomite, sandstone, gravel, granite, disincate, gabbro, basalt, and the like; and synthetic aggregate materials, such as industrial by-product aggregate materials, such as blast furnace slag, fly ash, municipal waste, and recycled concrete. In some cases, the rock or mineral is selected from aggregates including CaCO3, waste concrete, tropical sand, limestone, and fine waste dust. In selected cases, the seed structure includes aggregates, such as recycled aggregates, or aggregates produced via the subject methods. Additionally or alternatively, an embodiment of the seed structure includes waste concrete (e.g., from a demolished building structure). Additionally or alternatively, an embodiment of the seed structure includes tropical sand. Any metal carbonate including rocks, such as, but not limited to, limestone, marble, and coral rock, may be used. In some cases, the seed structure may be a coarse aggregate, such as brittle Pleistocene coral rock, as may be obtained from tropical regions (e.g., Florida) that are too weak to function as an aggregate for concrete. In this case, the brittle coral rock may be used as a seed, solid CO2-sequestering carbonates may be deposited in the interior pores, and the coarse aggregate may be suitable for use in concrete and may pass the Standard Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine (ASTM C535). In some cases, if lightweight aggregate is desired, the exterior surface is penetrated only by the solution of the deposit, leaving the inner core relatively "hollow" to create a lightweight aggregate for use in lightweight concrete.

[0108] The seed structure may range from a single object or a particulate composition, as desired. The seed structure may have a variety of different shapes, which may be regular or irregular, and a variety of different dimensions. The seed structure may have any suitable size (e.g., diameter), with sizes of interest ranging from 2 nm to 20 cm, such as 3 nm to 15 cm, such as 4 nm to 10 cm, including 5 nm to 5 cm. In some cases, the seed is a fine grain seed, such as a particulate composition, consisting of a plurality of particles. When the seed structure is a particulate composition, the size of the particles that make up the seed structure may vary in some cases from 0.01 to 1,000,000 μm, such as 0.1 to 100,000 μm. The percentage of seeds in the carbonate precipitate-seed composition may also vary in some cases from 0.1% to 90% w / w dry basis, such as 1% to 20% w / w dry basis.

[0109] In some embodiments, the seed structures may be introduced prior to precipitation of the metal carbonate. In some such embodiments, the seed structures may be included in an aqueous solution containing cations and / or dissolved inorganic carbon. In other embodiments, the seeds may be introduced to the carbonate after precipitation. In some cases, the seeds may be added to the carbonate precipitate in its aqueous suspension form during or after filtration, or to the slurry before, during, or after flocculation.

[0110] The carbonate composition and seeds, if present, may be mixed in the rotating drum for a period of time sufficient to produce the desired carbonate aggregate. The period of time may vary, but in some cases the period of time ranges from 10 minutes to 5 hours, such as 15 minutes to 3 hours or more. In other embodiments, the method may not include drying the resulting carbonate aggregate. Such embodiments may include curing the building product with its residual moisture / water, or residual curing liquid present in the product from the production process. They may also include subjecting the produced building product to a curing step in a humid or steamy environment. In some cases, combining the carbonate precipitate with the seed structure includes coating the seed structure with the carbonate precipitate. For example, if the seed structure is porous, the carbonate precipitate may occupy the space within the pores. In other cases, combining the carbonate precipitate with the seed structure includes coating the carbonate precipitate with the seed structure.

[0111] As mentioned above, the method may include hardening the resulting carbonate building material (e.g., aggregate). As used herein, "hardening" refers to a transformation to a hardened state that alters the crystal structure and / or morphological nano / microstructure of the compound. In some cases, hardening changes the initial CO2-sequestering solid composition (e.g., precipitate or aggregate composition) from a first polymorph to a second polymorph. Methods for hardening aggregate products are described, for example, in U.S. Patent Application Publication No. 2021 / 0403336, the disclosure of which is incorporated by reference in its entirety. Thus, embodiments of the present invention include contacting a building material (e.g., aggregate) with sufficient hardening liquid to produce a hardened building material or hardening via residual moisture in the produced product (i.e., the hardening liquid is present in the produced product, but it was not added to the building material). The hardening liquid is a composition that can be contacted with the initial CO2-sequestering composition, thereby hardening it and producing a hardened CO2-sequestering solid. The term "liquid" in "hardening liquid" means that the hardening composition includes a compound that is in a liquid state of matter, e.g., water. For example, the setting liquid may be an aqueous liquid, with water being the most abundant compound present in the setting liquid. In certain cases, the setting liquid may be selected from a carbonate setting liquid, a bicarbonate setting liquid, a phosphate setting liquid, a divalent alkaline earth metal setting liquid, or tap water. In some versions, the setting liquid is substantially free or completely free of any compounds dissolved in the water of the aqueous setting liquid. In other embodiments, the setting liquid includes water and compounds dissolved in the water, i.e., the setting liquid is a solution that includes solutes dissolved in a solvent. In some cases, the setting liquid also includes compounds in the solid state, i.e., solid compounds that are not dissolved in the liquid. In some embodiments, the setting liquid is an emulsion, i.e., it is a mixture of two or more liquids that normally form two immiscible layers, but the addition of an emulsifier causes the two layers to fuse together to form a single layer.

[0112] Some embodiments of the method include keeping the precipitated carbonate (and optionally the seeds) moist (i.e., with water) until the composition achieves the desired properties of the building material. Any protocol for keeping the composition moist can be used. For example, in some cases, the method includes keeping the already moist mixture moist by preventing water from evaporating (e.g., in a bag or pile), spraying with humidity, steam, and water. In some embodiments, curing includes placing the carbonate building material in a moist area (e.g., a humidity chamber). The humidity in the humidity chamber can vary and in some cases can range from 40% to 100%, e.g., 50% to 75%. In certain cases, the humidity chamber can be a bag, such as a plastic bag. In certain cases, the humidity chamber can be a pile, such as a covered pile.

[0113] In some cases, the curing step involves changing the compounds of the initial CO2 sequestration composition from a first crystal structure to a second crystal structure, and the curing compound allows or increases the rate of this change. In some cases, the curing liquid allows the temporary dissolution of solid compounds into the curing liquid, followed by returning these compounds to a solid state but transitioning to a second crystal structure. In some cases, the curing liquid favors the formation of the second crystal structure over the formation of the first crystal structure. In some embodiments, the curing liquid includes an ion, e.g., carbonate, that is also present in the initial CO2 sequestration composition. Due to solubility limitations, the presence of this ion in the curing liquid can help prevent an undesirably large amount of the initial CO2 sequestration composition from dissolving in and remaining in the curing liquid. In other words, the presence of this common ion can favor returning the compounds to a solid state but transitioning into a second crystal structure. In other cases, the curing compound can directly interact with the solid in the first crystal structure and change it to the second crystal structure without dissolving in the curing liquid.

[0114] In other embodiments, hardening occurs because the hardening compound changes the pH of the initial CO2 sequestering solid composition. In other words, the hardening liquid can have a pH that causes protonation or deprotonation of compounds in the initial CO2 sequestering solid composition. In some cases, the hardening process occurs because some solid compounds of the initial CO2 sequestering solid composition dissolve in the hardening liquid, thereby separating them from the sequestering solid. The hardening liquid can also contain compounds that transition from being dissolved in the hardening liquid to a solid state, thereby becoming part of the sequestering solid.

[0115] In some cases, the setting liquid has a sufficient concentration of dissolved inorganic carbon to produce the desired setting composition. Dissolved inorganic carbon (DIC) refers to the amount of carbonate ions (CO3 2- ), bicarbonate ions (HCO3), and CO2 dissolved in the liquid. In some cases, the hardening liquid has a DIC in the range of 0.01M to 10M, e.g., 0.05M to 5M, 0.1M to 4M, or 0.5M to 3M. For example, if the hardening liquid contains 1M carbonate ions, 0.2M bicarbonate ions, and 0.1M dissolved CO2, the dissolved inorganic carbon concentration will be 1.3M. In some cases, the hardening liquid has a concentration of positive ions in the range of 0.01M to 10M, e.g., 0.05M to 5M, 0.1M to 4M, or 0.5M to 3M, e.g., the positive ions may be Na + , K + , and NH4 + For example, in some cases, the hardening liquid is selected from the group consisting of Na + It has a concentration of ions.

[0116] In some cases, the setting liquid includes a carbonate setting liquid, i.e., the liquid contains carbonate ions (CO 2- ), carbonate compounds containing the bicarbonate ion (HCO3 2-), or both. In some cases, the carbonate compound has the formula M2CO3, where M is a monovalent positive ion, e.g., an alkali metal cation. For example, the carbonate compound can be sodium carbonate (Na2CO3), ammonium carbonate ((NH4)2CO3), or potassium carbonate (K2CO3). In some cases, the setting liquid includes a bicarbonate compound, e.g., of formula MHCO3, where M is a monovalent positive ion, e.g., an alkali metal cation. Exemplary bicarbonate compounds include sodium bicarbonate (NaHCO3), ammonium bicarbonate (NH4HCO3), and potassium bicarbonate (K2HCO3).

[0117] In some cases, the setting liquid may be a phosphate setting liquid, i.e., may contain a phosphate compound. As used herein, "phosphate" refers to a compound that contains four oxygen atoms bonded to a phosphorus atom, i.e., a compound that contains a phosphate group. In some cases, the phosphate compound has the formula PO4R 1 R 2 R 3 wherein R 1 , R 2 , and R 3 are each independently hydrogen or a negative charge. 1 , R 2 , and R 3 When R is all hydrogen atoms, the compound is H3PO4, which is referred to herein as phosphoric acid. 1 and R 2 is hydrogen and R 3 is negatively charged, the resulting compound is H2PO4 - which is referred to herein as the dihydrogen phosphate ion, and the hardening liquid contains an alkali metal cation, e.g., Na + Or K + and the corresponding positive ions such as R 1 is hydrogen and R 2 and R 3 is negatively charged, the resulting compound is HPO4 2- which is referred to herein as a hydrogen phosphate ion, and the hardening liquid has one or more corresponding positive ions. 1, R 2 , and R 3 are all negatively charged, the compound is PO4 3- which is referred to herein as a phosphate ion, and the setting liquid has one or more corresponding positive ions. Phosphate setting liquids can also include polyphosphate groups, i.e., groups having two or more phosphorus atoms, each bonded to four oxygen atoms, with one of the oxygen atoms bonded to two phosphorus atoms. An exemplary polyphosphate compound has the formula HO-(POH) n -H, where n is an integer of 2 or more, e.g., 2 to 10,000. In some cases, the polyphosphate is deprotonated, i.e., one or more of the hydrogen atoms are replaced with a negative charge, and the setting liquid contains the corresponding positive ion, e.g., Na + and K + In some cases, the phosphate compound is an organophosphate compound, i.e., a compound of the formula PO4R 1 R 2 R 3 wherein R 1 , R 2 , and R 3 are each independently a hydrogen atom, a hydrocarbon group, or a negative charge; R 1 , R 2 , and R 3 At least one of the groups is a hydrocarbon group.

[0118] In some cases, the setting liquid is a divalent alkaline earth metal setting liquid, such as calcium, magnesium, etc., e.g., a calcium setting liquid, i.e., a divalent alkaline earth metal ion, e.g., calcium ion (Ca 2+ ) Magnesium ion (Mg 2+In some cases, the divalent alkaline earth metal, e.g., calcium, setting liquid has a divalent alkaline earth metal, e.g., calcium ion concentration in the range of 0.01M to 1.0M, e.g., 0.02M to 0.2M, or 0.09M to 0.9M. Such setting liquids may be varied as desired so long as they provide a source of divalent alkaline earth ions, and examples of such setting liquids include, but are not limited to, CaCl 2、 MgCl2, etc. When the hardening liquid is a calcium hardening liquid, the calcium hardening liquid is Ca 2+ and DIC to form additional CO sequestering solid. For example, the set liquid is a filtrate from preparing an initial CO sequestering solid composition or a filtrate from a process that includes contacting an aqueous capture liquid that includes a cation source with a gaseous CO source under conditions sufficient to produce an initial CO sequestering solid.

[0119] In some cases, the setting liquid includes water, i.e., the setting liquid includes water. The water may be obtained from any convenient source, and in some cases, the water is obtained from a municipal water supply. The term "municipal water supply" refers to potable water (i.e., drinking water) that is deemed safe for human consumption and delivered by pipe to two or more businesses or homes, such as 100 or more businesses or homes. In some cases, the water may be recycled water, which may or may not be potable. In some cases, the setting liquid includes any combination of the setting liquids mentioned above, i.e., bicarbonate setting liquid, carbonate setting liquid, phosphate setting liquid, a composite setting liquid composed of a combination of an alkaline earth metal, e.g., calcium, setting liquid, and water, or any composite thereof.

[0120] When the carbonate coating is produced using a CO2 sequestration process, for example as described above, the resulting aggregate composition may be considered to be a CO2 sequestration aggregate composition. In some cases, the CO2 sequestration aggregate composition includes a core and aggregate particles having a CO2 sequestration carbonate coating on at least a portion of the surface of the core. The CO2 sequestration carbonate coating is made from a CO2 sequestration carbonate material. By "CO2 sequestration carbonate material" is meant a material that stores a significant amount of CO2 in a storage stable form such that CO2 gas is not readily produced from the material and released into the atmosphere. In certain embodiments, the CO2 sequestration material comprises 5% or more, e.g., 10% or more, 25% or more, e.g., 50% or more, e.g., 75% or more, e.g., 90% or more CO2, e.g., present as one or more carbonate compounds. In further embodiments, the CO2 sequestration material may form independent particles without a substrate particle. The CO2 sequestration material present in the coating according to the present invention may include one or more carbonate compounds. The amount of carbonate in the CO2 sequestration material, as determined, for example, by coulometry, can be 10% or more, 20% or more, 40% or more, such as 70% or more, for example 80% or more, such as 100%, when the particles are formed without a core substrate, or when the core substrate is a particle formed without a core substrate.

[0121] FIG. 9, discussed in more detail in the experimental section below, shows the effect of seeding to convert ACC and vaterite polymorphs to the desired aragonite polymorph. As shown in FIG. 9, the ratio of different calcium carbonate polymorphs changes throughout the formation, seeding, and hardening steps to produce a building material end product from precipitated calcium carbonate. The use of seeding can be employed to synthesize metal carbonates of desired crystal structure and morphology at scales ranging from nm to m. Although described herein with respect to building materials, seeding in embodiments of the invention has utility in additional areas beyond building materials and CO2 sequestration.

[0122] In some cases, undifferentiated polymorphic precursors present in the carbonate slurry may produce undesired differentiated polymorphic precursors that are not suitable for use as building materials (Box 104, FIG. 1). By "undesired" differentiated polymorphic precursors we mean that the differentiated polymorphic precursor in question is not useful for producing the building material of interest. However, as discussed above, the undesired differentiated polymorphic precursors may be treated under conditions sufficient to form a particular polymorph suitable for use as a building material, such as by adding a seed structure or by hardening (Box 105, FIG. 1).

[0123] In certain embodiments, the method begins with calcium carbonate containing at least one of a multipotent polymorph precursor, an amorphous calcium carbonate, a desired polymorph precursor, an undesired polymorph precursor, a vaterite polymorph precursor, and vaterite. Optionally, the calcium carbonate is freshly precipitated and in the form of an aqueous solution or a carbonate slurry containing water.

[0124] The method may then include adding the desired polymorph and mixing until homogeneous. In such a case, calcium carbonate seeds of the desired polymorph are added to the slurry. The seeds may be added at 0.01% to 90% w / w (dry basis), including 1% to 20% w / w (dry basis). Alternatively, calcium carbonate seeds may be added to the aqueous solution prior to precipitation (formation) of calcium carbonate.

[0125] In some embodiments, prior to agglomeration, water / water solution is added or removed from the calcium carbonate until a slurry concentration of 15%-50% water containing 18%-25% water is achieved. The calcium carbonate (precipitate-seed mixture) is formed into the desired particle shape and particle size. In one example, these are coarse aggregates (gravel) and in another example, the desired particle size is sand. In one example, the precipitate-seed-water mixture is spun in a rotating drum. In another example, the precipitate-seed-water mixture is poured into a mold.

[0126] The method may then include placing the carbonate product in an environment where moisture is retained (i.e., "curing" the product). The humid environment may include, for example, a humidity chamber or a sealed container that does not allow evaporation. In additional cases, the carbonate product is exposed to steam. Optionally, this environment may be temperature controlled. Once the carbonate aggregate / building material has reached maximum strength (e.g., compressive strength, tensile strength, etc.), it may then be removed from the humid environment.

[0127] In one embodiment of this protocol, undesired differentiated polymorphic precursors may be seeded with aragonite polymorphic crystals to produce suitable building materials. An example of this embodiment is described in the following steps: 1. Prepare a calcium-alkaline solution by dissolving recycled concrete aggregate in ammonium chloride or by preparing a solution from commercially available chemicals. In this embodiment, the solution contains: a. 0.38M Ca 2+ b.0.29M NH4 + c.0.34M NH3 d.5mM Mg 2+ e.8mM(SO4) 2- 2. Using a bubbling stone, contact 7% (range 6-9% during the experiment) gaseous CO2 w / w in air with the calcium-alkaline solution. Monitor the pH and stop the reaction when the alkali reacts / a pH of 7 is reached. 3. Allow the solid phase to fall out of the liquid by settling for 30-45 minutes. 4. Decant the liquid phase 5. Filter the solid phase using a Buchner funnel and 1.5 um filter paper. 6. Rinse the solid phase four times with water. 7. Filter the solid phase using a Büchner funnel until the moisture content of the slurry / solid phase is 30-38% 8. Powdered aragonite (a crystalline form of calcium carbonate) is mixed using a stand mixer at 10% w / w of the total (final product) calcium carbonate until the precipitate-water-aragonite mixture is uniform, approximately 2 minutes on low speed. a. Preparation of powdered aragonite: i. Aragonite is crushed using a jaw crusher ii. In this example, the crushed aragonite is sieved to mesh size #50×#100 (0.15-0.30 mm). 9. The precipitate-aragonite-water mixture is transferred to a rotating drum and low-temperature heated air (85F) is passed through the drum. 10. The mixture is rolled in the drum for approximately 20 minutes until the desired (gravel) particle size aggregate is formed. 11. Transfer the aggregate to the hardening chamber: a 75°C high humidity (70-80% RH) chamber. 12. Keep the aggregate in the curing chamber for 2 days 13. Remove the aggregate from the curing chamber and allow to dry at ambient conditions.

[0128] In another embodiment of this protocol, undesired differentiated polymorphic precursors may be seeded with calcite polymorph crystals to generate suitable building materials, as shown, for example, in FIG. 6. FIG. 6 presents a flow chart showing the steps to form a desired CaC03 product by seeding. CaC03 is precipitated (601) and contains at least one of the following: multipotent polymorphic precursors, undesired polymorphic precursors, desired polymorphic precursors, amorphous CaC03, vaterite, and / or aragonite. This precipitated CaC03 containing at least one of the listed polymorphs is combined with the desired crystalline CaC03 seeds (602). The seeds may be added either before or after precipitating the CaC03. The mixture of precipitated CaC03 and seeds (603) is then hardened with moisture / water (604). The moisture may be obtained from any convenient source. Optionally, the temperature may be controlled while hardening with moisture, for example by warming. After the product hardens, it is in the form of a product such as a building product or aggregate (605).

[0129] In some embodiments, the method of the present invention comprises the following steps. 1. A calcium-alkaline solution is prepared by dissolving recycled concrete aggregate in ammonium chloride or by preparing a solution from commercially available chemicals. In this embodiment, the solution contains: a. 0.38M Ca 2+ b.0.29M NH4 + c.0.34M NH3 d.5mM Mg 2+ e.8mM(SO4) 2- 2. Using a bubbling stone, contact 7% (range 6-9% during the experiment) gaseous CO2 w / w in air with the calcium-alkaline solution. Monitor the pH and stop the reaction when the alkali reacts / a pH of 7 is reached. 3. Allow the solid phase to fall out of the liquid by settling for 30-45 minutes. 4. Decant the liquid phase 5. Filter the solid phase using a Buchner funnel and 1.5 um filter paper. 6. Rinse the solid phase four times with water. 7. Filter the solid phase using a Büchner funnel until the moisture content of the slurry / solid phase is 30-38% 8. Powdered calcite (a crystalline form of calcium carbonate) is mixed using a stand mixer at 10% w / w of the total (final product) calcium carbonate until the precipitate-water-aragonite mixture is uniform, approximately 2 minutes on low speed. a. Preparation of powdered calcite: i. Crush the calcite by hand ii. In this example, the crushed calcite is sieved to <0.15 mm 9. The sediment-calcite-water mixture is transferred to a rotating drum and low-temperature heated air (85F) is passed through the drum. 10. The mixture is rolled in the drum for approximately 20 minutes until the desired (gravel) particle size aggregate is formed. 11. Transfer the aggregate to the hardening chamber: a 75°C high humidity (70-80% RH) chamber. 12. Keep the aggregate in the curing chamber for 5 days 13. Remove the aggregate from the curing chamber and allow to dry at ambient conditions.

[0130] Method for Producing a Composition Containing a Building Material Aspects of the invention further include the production of compositions comprising the building materials (e.g., aggregates) of the invention. In some embodiments, the subject compositions are settable compositions. Settable compositions of the invention, e.g., concrete and mortar, are produced by combining hydraulic cement with a quantity of aggregate (e.g., produced as described above) and water, either simultaneously or by precombining the cement with the aggregate and then combining the resulting dry components with water. The liquid phase, e.g., aqueous fluid, with which the dry components (i.e., concrete dry composite) are combined to produce a settable composition, e.g., concrete, can vary from pure water to water containing one or more solutes, additives, co-solvents, etc., as desired. The ratio of dry components to liquid phase combined in preparing the settable composition can vary and in certain embodiments ranges from 2:10 to 7:10, such as 3:10 to 6:10, including 4:10 to 6:10.

[0131] As used herein, the term "cement" refers to a particulate composition that hardens and hardens after being combined with a hardening fluid, e.g., an aqueous solution such as water. The particulate composition that constitutes a given cement may include particles of various sizes. In some cases, a given cement may be composed of particles having a longest cross-sectional length (e.g., diameter within a spherical particle) that ranges from 1 nm to 100 μm, e.g., 10 nm to 20 μm and 15 nm to 10 μm inclusive. Cement of interest includes hydraulic cements. As used herein, the term "hydraulic cement" refers to cement that hardens when mixed with a hardening fluid due to one or more chemical reactions that are independent of the moisture of the mixture and are stable in an aqueous environment. Thus, hydraulic cements may harden when exposed to water or constantly wet weather conditions. Hydraulic cements of interest include, but are not limited to, Portland cements, modified Portland cements, and blended hydraulic cements.

[0132] Following combination of the ingredients to produce a settable composition (e.g., concrete), the settable composition, in some cases, is initially a flowable composition and then set after a given period of time. Set times may vary and in certain embodiments range from 30 minutes to 48 hours, such as 30 minutes to 24 hours, including 1 hour to 4 hours.

[0133] The components of the solidifiable composition can be combined using any convenient protocol. The materials can be mixed at the time of operation, or some or all of the materials can be premixed. Alternatively, some of the materials can be mixed with water, with or without admixtures such as high-range reducing water admixtures, and then the remaining materials can be mixed with them. As a mixing device, any conventional device can be used. For example, Hobart mixers, tilted cylinder mixers, Omni mixers, Henschel mixers, V-type mixers, and Nauta mixers can be used.

[0134] In some embodiments, the formation of the settable composition of the present invention includes the addition of admixtures. "Admixtures" are referred to in their conventional sense to describe materials other than cement, water, and aggregates that are added to form a settable composition (e.g., concrete). Admixtures may be added in some cases to impart desired properties to the settable composition (e.g., corrosion resistance, hydration control, etc.). Admixtures of interest include finely divided mineral admixtures such as cementitious materials, pozzolans, pozzolans and cementitious materials, and nominally inert materials. Pozzolans include diatomaceous earth, opalescent chert, clay, shale, fly ash, silica fume, volcanic ash, and floatstone, which are some of the known pozzolans. Certain granulated blast furnace slags and high calcium fly ashes have both pozzolani and cementitious properties. Nominally inert materials can also include finely divided ore, dolomite, limestone, marble, granite, and others. Fly ash is defined in ASTM C618. Other types of admixtures of interest include plasticizers, accelerators, retarders, aerators, foaming agents, reduced water, corrosion inhibitors, and pigments. Admixtures of interest therefore include, but are not limited to, set accelerators, set retarders, aerators, defoamers, alkali reactivity reducers, bonding admixtures, dispersants, coloring admixtures, corrosion inhibitors, moisture-proof admixtures, gas-forming agents, permeability reducers, pump aids, shrinkage compensation admixtures, fungicidal admixtures, germicidal admixtures, insecticidal admixtures, rheology modifiers, finely divided mineral admixtures, pozzolans, aggregates, wetting agents, strength enhancers, water repellents, and any other concrete or mortar admixtures or additives. Admixtures are well known in the art, and any suitable admixture of the above types or any other desired types may be used. See, for example, U.S. Patent No. 7,735,274, which is incorporated herein by reference in its entirety.

[0135] The subject methods may additionally include producing a concrete dry composite that, when combined with a suitable solidification liquid, produces a settable composition that sets and hardens into concrete or mortar. The concrete dry composites described herein include an amount of aggregate (e.g., CO2 sequestering aggregate produced as described above) and a cement, such as a hydraulic cement. The setting and hardening of the product produced by combining the concrete dry composite of the present invention with an aqueous liquid results from the formation of hydrates formed from the cement upon reaction with water, the hydrates being essentially insoluble in water.

[0136] Also of interest are formed building materials. Formed building materials of interest include the building materials (e.g., aggregates) of the present invention. The formed building materials of the present invention can vary widely. By "formed" it is meant that they have been processed, e.g., molded, cast, cut, or otherwise produced, into an artificial structure that defines a physical shape, i.e., configuration. Formed building materials are distinct from amorphous building materials, e.g., particulate (such as powder) compositions that do not have a defined, stable shape, but instead conform to the container in which they are held, e.g., a bag or other container. Exemplary formed building materials include, but are not limited to, bricks, boards, conduits, beams, basins, columns, drywall, and the like. Further examples and details regarding formed building materials include those described in U.S. Pat. No. 8,431,100, the disclosure of which is incorporated herein by reference.

[0137] In some embodiments, the formed building material can include one or more different carbonate compounds, e.g., two or more different carbonate compounds, e.g., three or more different carbonate compounds, five or more different carbonate compounds, etc., including non-differentiated amorphous carbonate compounds. The carbonate compounds are represented by molecular formulation X. m (CO3) nwhere X is any element or combination of elements capable of chemically bonding with a carbonate group or groups, X in certain embodiments is an alkaline earth metal and not an alkali metal, and m and n are stoichiometric positive integers. These carbonate compounds have one or more structural waters in the molecular formula, X m (CO3) n The amount of carbonate in the building material formed may have a molecular formula of HO. The amount of carbonate in the building material formed may be, for example, 10% or more, including 25% or more, 50% or more, 60% or more, as determined by querometry using a protocol described as querometric titration.

[0138] The method of the present invention may additionally include constructing an architectural structure using the building materials described herein. The architectural structure may be any structure in which the building materials may be used, such as a building, a dam, a levee, a road, or any other man-made structure incorporating aggregates, rocks, or settable compositions. The architectural structure may be constructed via any suitable method using techniques known to those skilled in the art of construction.

[0139] Building materials produced by the method As discussed above, the methods of the invention can be used to produce building materials such as metal carbonate aggregates (synthetic stone or sand, depending on particle size) or metal carbonate coated aggregates, for use in concrete and other applications. The carbonate-containing aggregates can be conventional or lightweight aggregates. An embodiment of the invention includes a CO2-sequestering aggregate composition. The CO2-sequestering aggregate composition includes aggregate particles having a core and a CO2-sequestering carbonate coating on at least a portion of a surface of the core. The CO2-sequestering carbonate aggregate or aggregate coating is made from a CO2-sequestering carbonate material, for example, as described above.

[0140] The CO2-sequestering carbonate material present in the carbonate aggregate or coating of the carbonate-coated particles of the subject aggregate composition can vary. In some cases, the carbonate material is a highly reflective microcrystalline / amorphous carbonate material. The material can be highly reflective, so that a coating including the same can have a high total surface reflectance (TSR) value. TSR can be determined using any convenient protocol, for example, the ASTM E1918 standard test method for measuring solar reflectance of horizontal and low-sloping surfaces in the field (see also R. Levinson, H. Akbari, P. Berdahl, Measuring solar reflectance-Part II: review of practical methods, LBNL 2010).

[0141] In some cases, carbonate aggregates or carbonate coated aggregates that include carbonate materials are highly reflective of near infrared (NIR) light, in some cases ranging from 10-99%, e.g., 50-99%, by NIR light it is meant light having wavelengths in the range of 700 nanometers (nm) to 2.5 mm. NIR reflectance may be determined using any convenient protocol, such as ASTM C1371-04a(2010)e1, Standard Test Method for Determining the Emission of Materials Near Room Temperature Using a Portable Emissometer (http: / / www(dot)astm(dot)org / Standards / C1371(dot)htm), or ASTM G173-03(2012), Reference Solar Spectral Irradiance: Standard Tables for Straight Normal and Hemispherical Surfaces Inclined at 37° (http: / / rredc(dot)nrel(dot)gov / solar / spectra / am1(dot)5 / ASTMG173 / ASTMG173(dot)html). In some cases, the coating exhibits NIR reflectance values ​​ranging from Rg;0=0.0 to Rg;0=1.0, e.g., from Rg;0=0.25 to Rg;0=0.99, including from Rg;0=0.40 to Rg;0=0.98, e.g., as measured using the protocol described above.

[0142] In some cases, the carbonate aggregate or coating of the carbonate coated aggregate is highly reflective of ultraviolet (UV) light, in some cases ranging from 10 to 99%, e.g., 50 to 99%. By UV light is meant light having a wavelength ranging from 400 nm to 10 nm. UV reflectance may be determined using any convenient protocol, such as ASTM G173-03 (2012), Standard Tables for Reference Solar Spectral Irradiation: Straight Normal and Hemispherical for 37° Inclined Surfaces. In some cases, the material exhibits UV values ​​ranging from Rg;0=0.0 to Rg;0=1.0, e.g., Rg;0=0.25 to Rg;0=0.99, including Rg;0=0.4 to Rg;0=0.98, e.g., as measured using the protocol described above.

[0143] In some cases, the carbonate aggregate or coating of the carbonate coated aggregate reflects visible light, e.g., visible light whose reflectance may vary from 10 to 99%, e.g., 10 to 90%. By visible light is meant light having a wavelength in the range of 380 nm to 740 nm. Visible light reflectance properties may be determined using any convenient protocol, such as ASTM G173-03 (2012), Standard Tables for Reference Solar Spectral Irradiation: Straight Normal and Hemispherical Shapes of 37° Inclined Surfaces. In some cases, the carbonate aggregate or coating of the carbonate coated aggregate exhibits visible light reflectance values ​​in the range of Rg;0=0.0 to Rg;0=1.0, e.g., Rg;0=0.25 to Rg;0=0.99, including Rg;0=0.4 to Rg;0=0.98, e.g., measured using the protocol described above.

[0144] The material constituting the carbonate component is, in some cases, amorphous or microcrystalline. When the material is nano- or microcrystalline, the crystal size (e.g., as determined using the Scherrer equation applied to the FWHM of the X-ray diffraction pattern) is small, in some cases, 1000 microns in diameter or less, e.g., 100 microns in diameter or less, including 10 microns in diameter or 100 nanometers in diameter or less. In some cases, the crystal size is in the range of 1000 μm to 0.001 μm in diameter, e.g., 10 to 0.001 μm, including 1 to 0.001 μm. In some cases, the crystal size is selected with consideration of the wavelength of light to be reflected. For example, if light within the visible spectrum is reflected, the crystal size range of the material may be selected to be less than one-half the "reflected" range, to create a photonic band gap. For example, if the reflected wavelength range of light is 100 to 1000 nm, the crystal size of the material may be selected to be 50 nm or less, e.g., 5 to 25 nm, such as in the range of 1 to 50 nm. In some embodiments, materials produced by the methods of the invention may include rod-shaped crystals and amorphous solids. The rod-shaped crystals may vary in structure and in certain embodiments have a length to diameter ratio in the range of 500 to 1, such as 10 to 1. In certain embodiments, the length of the crystals ranges from 0.5 μm to 500 μm, such as 5 μm to 100 μm. In yet other embodiments, a substantially completely amorphous solid is produced.

[0145] The density, porosity, and permeability of the carbonate aggregate or carbonate coated aggregate may vary depending on the application. With respect to density, the density of the material may vary, but in some cases the density is less than 5 g / cm 3 ~0.01g / cm 3 , e.g. 3g / cm 3 ~0.3g / cm 3 2.7g / cm 3 ~0.4g / cm 3With respect to porosity, as determined by the BET method, as determined by gas surface adsorption (Brown Emmett Teller (e.g., E. Teller, J. Am. Chem. Soc., 1938, 60, 309. doi:10.1021 / ja01269a023), the porosity is, in some cases, greater than 100 m 2 / g~0.1m 2 / g, e.g. 60m 2 / g~1m 2 / g, and 2 / g~1.5m 2 / g. With respect to permeability, in some cases the permeability of a material may range from 0.1 to 100 Darcy, such as 1 to 10 Darcy, including 1 to 5 Darcy (e.g., as determined using the protocol set forth in H. Darcy, Les Fontaines Publiques de la Ville de Dijon, Dalmont, Paris (1856)). Permeability may also be characterized by assessing the absorption of the material. For example, the water absorption of a material, as determined by the absorption protocol, may range from 0 to 25%, e.g., 1 to 15%, including 2 to 9%, in some embodiments.

[0146] The hardness of the material may also vary. In some cases, the material exhibits a Mohs hardness of 3 or more, e.g., 5 or more, including 6 or more, and in some cases the hardness ranges from 3 to 8, such as 4 to 7, including 5 to 6 Mohs (e.g., as determined using the protocol set forth in the American Federation of Mineralogical Societies, "Mohs Scale of Mineral Hardness"). Hardness may also be expressed in terms of tensile strength, e.g., as determined using the protocol set forth in ASTM C1167. In some such cases, the material may exhibit a compressive strength of 100 to 3,000 N, such as 400 to 2,000 N, including 500 to 1,800 N.

[0147] In some embodiments, the carbonate material includes one or more contaminants that are predicted not to leach into the environment by one or more tests selected from the group consisting of the Toxicity Characteristic Leaching Procedure, Extraction Procedure Toxicity Test, Synthetic Precipitation Leaching Procedure, California Waste Extraction Test, Soluble Threshold Limit Concentration, American Society for Testing Materials Extraction Test, and Multiple Extraction Procedure. The tests and combinations of tests may be selected depending on the possible contaminants and storage conditions of the composition. For example, in some embodiments, the composition may include As, Cd, Cr, Hg, and Pb (or products thereof), each of which may be found in the exhaust gas stream of a coal-fired power plant. TCLP may be an appropriate test for the aggregates described herein, since TCLP tests for As, Ba, Cd, Cr, Pb, Hg, Se, and Ag. In some embodiments, the carbonate composition of the present invention includes As, and the composition is predicted not to leach As into the environment. For example, a TCLP extract of the composition may provide less than 5.0 mg / L As, indicating that the composition is not harmful with respect to As. In some embodiments, the carbonate compositions of the invention include Cd and the compositions are not predicted to leach Cd into the environment. For example, a TCLP extract of the composition may provide less than 1.0 mg / L of Cd, indicating that the composition is not detrimental with respect to Cd. In some embodiments, the carbonate compositions of the invention include Cr and the compositions are not predicted to leach Cr into the environment. For example, a TCLP extract of the composition may provide less than 5.0 mg / L of Cr, indicating that the composition is not detrimental with respect to Cr. In some embodiments, the carbonate compositions of the invention include Hg and the compositions are not predicted to leach Hg into the environment. For example, a TCLP extract of the composition may provide less than 0.2 mg / L of Hg, indicating that the composition is not detrimental with respect to Hg. In some embodiments, the carbonate compositions of the invention include Pb and the compositions are not predicted to leach Pb into the environment. For example, a TCLP extract of the composition may provide less than 5.0 mg / L of Pb, indicating that the composition is not detrimental with respect to Pb.In some embodiments, carbonate compositions and aggregates comprising the same of the present invention may be non-toxic with respect to a combination of different contaminants in a given test. For example, a carbonate composition may be non-toxic with respect to all metal contaminants in a given test. The TCLP extract of the composition may be, for example, less than 5.0 mg / L in As, 100.0 mg / L in Ba, 1.0 mg / L in Cd, 5.0 mg / mL in Cr, 5.0 mg / L in Pb, 0.2 mg / L in Hg, 1.0 mg / L in Se, and 5.0 mg / L in Ag. In fact, most, if not all, of the metals tested in the TCLP analysis for the compositions of the present invention may be below the detection limit. In some embodiments, a carbonate composition of the present invention may be non-toxic with respect to all (e.g., inorganic, organic, etc.) contaminants in a given test. In some embodiments, the carbonate compositions of the present invention may be non-toxic with respect to all contaminants in any combination of tests selected from the group consisting of the Toxicity Characteristic Leaching Procedure, Extraction Procedure Toxicity Test, Synthetic Precipitation Leaching Procedure, California Waste Extraction Test, Soluble Threshold Limit Concentration, American Association of Testing and Materials Extraction Testing, and Multiple Extraction Procedure. Thus, carbonate compositions and aggregates including the same of the present invention may effectively sequester CO2 (e.g., as carbonates, bicarbonates, or combinations thereof) along with various chemical species (or by-products thereof) from waste gas streams, industrial waste sources of divalent cations, industrial waste sources of proton-removing agents, or combinations thereof that may be considered contaminants if released into the environment. The compositions of the present invention incorporate environmental contaminants (e.g., metals and by-products of metals such as Hg, Ag, As, Ba, Be, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, Zn, or combinations thereof) in a non-leachable form.

[0148] The aggregate composition of the present invention includes particles having a CO2 sequestering carbonate coating on at least a portion of the core region and surface of the core, also referred to as "carbonate coated aggregate." The coating may cover 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, including 95% or more of the core surface. The thickness of the carbonate layer may vary as desired. In some cases, the thickness may range from 0.1 μm to 10 mm, such as 1 μm to 1000 μm, including 10 μm to 500 μm.

[0149] The core of the coated particles of the aggregate composition described herein can vary widely. The core can be composed of any convenient aggregate material. Examples of suitable aggregate materials include, but are not limited to, natural mineral aggregate materials, such as carbonate rock, sand (e.g., natural silica sand), sandstone, gravel, granite, disincate, gabbro, basalt, and the like; and synthetic aggregate materials, such as industrial by-product aggregate materials, such as blast furnace slag, fly ash, municipal waste, and recycled concrete. In some cases, the core comprises a material different from the carbonate coating.

[0150] In some cases, the aggregate is a lightweight aggregate. In such cases, the core of the coated particles of the aggregate composition described herein may vary widely, so long as it provides the desired lightweight aggregate composition when coated. The core may be composed of any convenient material. Examples of suitable aggregate materials include, but are not limited to, conventional lightweight aggregate materials, such as naturally occurring lightweight aggregate materials, such as crushed volcanic rock, e.g., pumice, scoria or tuff, and synthetic materials, such as heat-treated clay, shale, slate, diatomaceous earth, perlite, vermiculite, blast furnace slag, and fly ash, as well as uncommon porous materials, such as crushed coral, synthetic materials, such as polymers and low-density polymeric materials, wood, fibrous materials, cement kiln dust residual materials, recycled glass, various volcanic minerals, granite, silica-bearing minerals, mine tailings, and the like.

[0151] The physical properties of the coated particles of the aggregate composition may vary. The aggregates of the present invention have densities that may vary, so long as the aggregate provides the desired properties for the application in which it is to be used, e.g., the building material in which it is to be used. In certain cases, the density of the aggregate particles may range from 1.1 to 5 gm / cc, e.g., 1.3 gm / cc to 3.15 gm / cc, including 1.8 gm / cc to 2.7 gm / cc. Other particle densities in embodiments of the present invention, e.g., for lightweight aggregates, may range from 1.1 to 2.2 gm / cc, e.g., 1.2 to 2.0 g / cc or 1.4 to 1.8 g / cc. In some embodiments, the present invention provides a densification agent having a density of 50 lb / lb / ft 3 ~200lb / ft 3 , or 75 lb / ft 3 ~175lb / ft 3 , or 50 lb / ft 3 ~100lb / ft 3 , or 75 lb / ft 3 ~125lb / ft 3 , or lb / ft 3 ~115lb / ft 3 , or 100 lb / ft 3 ~200lb / ft 3 , or 125 lb / ft 3 ~lb / ft 3 , or 140 lb / ft 3 ~160lb / ft 3 , or 50 lb / ft 3 ~200lb / ft 3 Some embodiments of the present invention provide lightweight aggregates, e.g., aggregates with bulk densities (unit weight) in the range of 75 lb / ft 3 ~125lb / ft 3 , e.g. 90 lb / ft 3 ~115lb / ft 3 In some cases, the lightweight aggregate has a bulk density (unit weight) of 50 to 1,200 kg / m 3 , e.g. 80~11kg / m 3 The weight ranges from 0.01 to 0.01.

[0152] The hardness of the aggregate particles making up the aggregate composition of the present invention may also vary, and in some cases the hardness, expressed on the Mohs scale, may range from 1.0 to 9, such as 1 to 7, including 1 to 6 or 1 to 5. In some embodiments, the Mohs hardness of the aggregate of the present invention ranges from 2 to 5, or 2 to 4. In some embodiments, the Mohs hardness ranges from 2 to 6. Other hardness scales, such as the Rockwell, Vickers, or Brinell scales, may also be used to characterize the aggregates, and values ​​equivalent to those on the Mohs scale may be used to characterize the aggregates of the present invention. For example, a Vickers hardness rating of 250 corresponds to a Mohs rating of 3, and conversion between scales is known in the art.

[0153] The abrasion resistance of aggregates may also be important for use in road surfaces, for example, where highly abrasion resistant aggregates are useful to protect surfaces from abrasion. Abrasion resistance (i.e., abrasion value) is related to, but not the same as, hardness. Aggregates of the present invention include aggregates having abrasion resistance similar to, or better than, natural limestone, as well as aggregates having abrasion resistance less than natural limestone, as measured by art-accepted methods such as ASTM C131-03, the Los Angeles Abrasion Test, and the Micro Deval Test. In some embodiments, aggregates of the present invention have an abrasion resistance of less than 50%, or less than 40%, or less than 35%, or less than 30%, or less than 25%, or less than 20%, or less than 15%, or less than 10%, as measured by the above-mentioned ASTM C131-03. In some embodiments, the aggregates of the present invention have an abrasion value of less than 40%, or less than 35%, or less than 30%, or less than 25%, or less than 20%, or less than 15%, or less than 10% as measured by the Los Angeles Abrasion Test. In some embodiments, the aggregates of the present invention have an abrasion value of less than 25%, or less than 20%, or less than 15%, or less than 10% as measured by the MicroDeval Test.

[0154] The aggregates of the present invention may also have a porosity within a particular range. As will be appreciated by those skilled in the art, in some cases high porosity aggregates are desired, in other cases medium porosity aggregates are desired, and in other cases low porosity or non-porous aggregates are desired. The porosity of the aggregates of some embodiments of the present invention, when expressed as % dry weight, as measured by water uptake after 60 minutes of complete immersion followed by oven drying, may range from 1 to 40%, such as 2 to 20%, or 2 to 15%, including 2 to 10%, or even 3 to 9%.

[0155] The size of the aggregate particles may vary. The aggregate compositions of the present invention are, in some embodiments, particulate compositions that may be classified as fine or coarse. Fine aggregates according to embodiments of the present invention are particulate compositions that pass almost entirely through a No. 4 sieve (ASTM C125 and ASTM C33). Fine aggregate compositions according to embodiments of the present invention have an average particle size in the range of 10 μm to 4.75 mm, e.g., 50 μm to 3.0 mm, including 75 μm to 2.0 mm. Coarse aggregates according to embodiments of the present invention are compositions that are primarily retained on a No. 4 sieve (ASTM C125 and ASTM C33). Coarse aggregate compositions according to embodiments of the present invention are compositions that have an average particle size in the range of 4.75 mm to 200 mm, e.g., 4.75 to 150 mm, including 5 to 100 mm. As used herein, "aggregate" can, in some embodiments, encompass larger sizes, such as 3 inches to 12 inches, or even 3 inches to 24 inches, or larger sizes, such as 12 inches to 48 inches, or greater than 48 inches.

[0156] Compositions containing building materials Aspects of the invention also include compositions that include the building materials (e.g., aggregates) of the invention. Compositions of interest include, for example, concrete dry composites, settable compositions, and building structures.

[0157] Concrete Drying Composite Concrete dry composites are provided that include the building materials (e.g., aggregates) of the present invention that, when combined with a suitable settable liquid (as described below), produce a settable composition that sets and hardens into concrete or mortar. The concrete dry composites described herein include an amount of aggregate, e.g., as described above, and a cement, such as hydraulic cement. The term "hydraulic cement" is used in its conventional sense to refer to a composition that sets and hardens after combination with water or a solution in which the solvent is water, e.g., an admixture solution. The setting and hardening of the product produced by the combination of the concrete dry composites of the present invention with an aqueous liquid results from the formation of hydrates that form from the cement upon reaction with water, the hydrates being essentially insoluble in water.

[0158] The aggregates of the present invention, when combined with pure Portland cement, are used in place of conventional natural rock aggregates used in conventional concrete. In certain embodiments, other hydraulic cements of interest are Portland cement blends. The phrase "Portland cement blends" includes hydraulic cement compositions that include a Portland cement component and a significant amount of non-Portland cement components. Since the cements of the present invention are Portland cement blends, the cement includes a Portland cement component. The Portland cement component may be any convenient Portland cement. As is known in the art, Portland cement is a powder composition produced by Portland cement clinker (greater than 90%), limited amounts of calcium sulfate to control the setting time, and up to 5% of minor constituents (as allowed by various standards). If the flue gas used to provide carbon dioxide for the reaction contains SOx, then there may be enough sulfate in the material precipitated as calcium sulfate, either as cement or aggregate to offset the need for additional calcium sulfate. As defined in European Standard EN197.1, "Portland cement clinker is a hydraulic material consisting of at least two-thirds calcium silicates (3CaO·SiO2 and 2CaO·SiO2), the remainder consisting of aluminum- and iron-containing clinker phases and other compounds. The ratio of CaO to SiO2 must be equal to or greater than 2.0. The magnesium content (MgO) must not exceed 5.0% by weight." The concern with MgO is that later in the setting reaction, magnesium hydroxide, hydrotalcite, may form, leading to deformation and weakening and cracking of the cement. In the case of magnesium carbonate containing cement, hydrotalcite is not formed as in the case of MgO. In certain embodiments, the Portland cement component of the present invention is any Portland cement that meets the ASTM Standards and Specifications for American Society for Testing and Materials C150 (Types I-VIII) (ASTM C50 - Standard Specification for Portland Cement). ASTM C150 covers eight types of Portland cement, each with different properties and used specifically for these properties.

[0159] Also of interest as hydraulic cements are carbonate-containing hydraulic cements, and methods for their manufacture and use, are described in U.S. Patent No. 7,735,274, the disclosure of which is incorporated herein by reference.

[0160] In certain embodiments, the hydraulic cement may be a blend of two or more different types of hydraulic cement, such as Portland cement and carbonate-containing hydraulic cement. In certain embodiments, the amount of the first cement, e.g., Portland cement, in the blend ranges from 10-90% (w / w), e.g., 30-70% (w / w), including 40-60% (w / w), e.g., a blend of 80% OPC and 20% carbonate hydraulic cement.

[0161] In some cases, the concrete dry composite composition, and concrete produced therefrom, has a Carbon Star Rating (CSR) that is lower than the CSR of a control composition that does not contain the aggregate of the present invention. Carbon Star Rating (CSR) is a value that characterizes the embodied carbon (in the form of CaCO3) of any product compared to how carbon dense the product itself is (i.e., in terms of CO2 production). CSR is a measure based on the embodied CO2 mass in a unit of concrete. Of the three components of concrete - water, cement, and aggregate, cement is the most significant contributor to CO2 emissions, approximately 1:1 by mass (one ton of cement produces approximately one ton of CO2). So if a cubic yard of concrete uses 600 pounds of cement, its CSR is 600. A cubic yard of concrete according to an embodiment of the invention containing 600 pounds of cement, where at least a portion of the aggregate is carbonate coated aggregate, for example as described above, may have a CSR of less than 600, for example, 550 or less, for example 500 or less, for example 400 or less, for example 250 or less, for example 100 or less, and in some cases the CSR may be a negative value, for example -100 or less, for example -500 or less, for example -1000 or less, and in some cases the CSR of a cubic yard of concrete having 600 pounds of cement may range from 500 to -5000, for example -100 to -4000, including -500 to -3000. To determine the CSR of a given cubic yard of concrete containing the carbonate coated aggregate of the invention, an initial value of CO2 generated due to the production of the cement component of the cubic yard of concrete is determined. For example, if the yard contains 600 pounds of cement, an initial value of 600 is assigned to the yard. The amount of carbonate coating in the yard is then determined. Since the molecular weight of carbonate is 100 a.u. and 44% of carbonate is CO2, the amount of carbonate coating present in the yard is multiplied by 0.44 and the resulting value is subtracted from the initial value to obtain the CSR of the yard.For example, if a given yard of concrete mix is ​​composed of 600 pounds of cement, 300 pounds of water, 1429 pounds of fine aggregate, and 1739 pounds of coarse aggregate, the weight of the yard of concrete is 4068 pounds and the CSR is 600. If 10% of the total mass of the aggregate in this mix is ​​replaced by a carbonate coating, for example as described above, the amount of carbonate present in the corrected yard of concrete is 317 pounds. Multiplying this value by 0.44 gives 139.5. Subtracting this number from 600 gives a CSR of 460.5.

[0162] solidifiable composition The settable compositions of the present invention, e.g., concretes and mortars, are produced by combining hydraulic cement with a quantity of the aggregate of the present invention and an aqueous liquid, e.g., water, either simultaneously or by precombining the cement with the aggregate and then combining the resulting dry components with water. The selection of coarse aggregate material for concrete mixtures using the cement compositions of the present invention may have a minimum size of about 3 / 8 inch and may vary in size from that minimum to a maximum of 1 inch or more, including gradations between these limits. Finely divided aggregates are less than 3 / 8 inch in size and can be regraded in much finer sizes, up to about 200-sieve size. Fine aggregates may be present in both mortars and concretes of the present invention. The weight ratio of cement to aggregate in the dry components of the cement may vary and in certain embodiments ranges from 1:10 to 4:10, such as 2:10 to 5:10, including 55:100 to 70:100.

[0163] The liquid phase, e.g., an aqueous fluid, into which the dry components are combined to produce a settable composition, e.g., concrete, can vary, as desired, from pure water to water containing one or more solutes, additives, co-solvents, etc. The ratio of dry components to liquid phase combined in preparing the settable composition can vary and in certain embodiments ranges from 2:10 to 7:10, such as 3:10 to 6:10, including 4:10 to 6:10.

[0164] In certain embodiments, cement may be used with one or more admixtures. Admixtures are compositions added to concrete to provide desirable properties not available in the basic concrete mix, or to modify the properties of concrete to make it easier to use or more suitable for a particular purpose or to reduce costs. As known in the art, an admixture is any material or composition, other than hydraulic cement, aggregate, and water, used as an ingredient in concrete or mortar to improve some characteristic or reduce its cost. The amount of admixture used may vary depending on the nature of the admixture. In certain embodiments, the amount of these ingredients ranges from 1 to 50% w / w, for example, 2 to 10% w / w.

[0165] Admixtures of interest include finely divided mineral admixtures such as cementitious materials, pozzolans, pozzolans and cementitious materials, and nominally inert materials. Pozzolans include diatomaceous earth, opalescent chert, clay, shale, fly ash, silica fume, volcanic ash, and floatstone, which are some of the known pozzolans. Certain granulated blast furnace slags and high calcium fly ashes have both pozzolanic and cementitious properties. Nominally inert materials can also include finely divided ore, dolomite, limestone, marble, granite, and others. Fly ash is defined in ASTM C618. Other types of admixtures of interest include plasticizers, accelerators, retarders, aerators, foaming agents, reduced water, corrosion inhibitors, and pigments.

[0166] Thus, admixtures of interest include, but are not limited to, set promoters, set retarders, aerators, defoamers, alkali reactivity reducers, bonding admixtures, dispersants, coloring admixtures, corrosion inhibitors, moisture-proofing admixtures, gas-forming agents, permeability reducers, pump aids, shrinkage compensating admixtures, fungicidal admixtures, germicidal admixtures, insecticidal admixtures, rheology modifiers, finely divided mineral admixtures, pozzolans, aggregates, wetting agents, strength enhancers, water repellents, as well as any other concrete or mortar admixtures or additives. Admixtures are well known in the art, and any suitable admixture of the above types or any other desired type may be used. See, for example, U.S. Patent No. 7,735,274, which is incorporated herein by reference in its entirety.

[0167] In certain embodiments, the settable compositions of the present invention include cement used in conjunction with fibers, for example, to form fiber-reinforced concrete. The fibers can be made from zirconia-containing materials, steel, carbon, fiberglass, or synthetic materials such as polypropylene, nylon, polyethylene, polyester, rayon, high-strength aramid (i.e., Kevlar®), or mixtures thereof.

[0168] The components of the solidifiable composition can be combined using any convenient protocol. The materials can be mixed at the time of operation, or some or all of the materials can be premixed. Alternatively, some of the materials can be mixed with water, with or without admixtures such as high-range reducing water admixtures, and then the remaining materials can be mixed with them. As a mixing device, any conventional device can be used. For example, Hobart mixers, tilted cylinder mixers, Omni mixers, Henschel mixers, V-type mixers, and Nauta mixers can be used.

[0169] Following combination of the ingredients to produce a settable composition (e.g., concrete), the settable composition, in some cases, is initially a flowable composition and then set after a given period of time. Set times may vary and in certain embodiments range from 30 minutes to 48 hours, such as 30 minutes to 24 hours, including 1 hour to 4 hours.

[0170] The strength of the set product may also vary. In certain embodiments, the strength of the set cement may range from 5 MPa to 70 MPa, such as 10 MPa to 50 MPa, including 20 MPa to 40 MPa. In certain embodiments, the set product produced from the cement of the present invention is highly durable, for example, as determined using the test method described in ASTM C1157.

[0171] architectural structure Aspects of the invention further include structures produced from the aggregates and settable compositions of the invention. Thus, further embodiments include man-made structures comprising the aggregates of the invention and methods for their production. Thus, in some embodiments, the invention provides man-made structures comprising one or more aggregates as described herein. The man-made structures may be any structure in which aggregates may be used, such as buildings, dams, embankments, roads, or any other man-made structure incorporating aggregates or rocks. In some embodiments, the invention provides man-made structures, e.g., buildings, dams, or roads, comprising the aggregates of the invention, where the aggregates may be produced from polymorphous precursor compositions, e.g., as described above. In some embodiments, the invention provides methods for producing structures, including providing the aggregates of the invention.

[0172] Utilities The subject aggregate compositions, and settable compositions containing them, are used in a variety of different applications, such as ground-stable CO2 sequestration products, as well as building or construction materials. Specific structures in which the building materials of the present invention find use include, but are not limited to, pavements, building structures, such as buildings, foundations, highways / roads, viaducts, parking structures, brick / block walls, and gates, fences, and pole foundations. The mortars of the present invention are used to bond building blocks (e.g., bricks) together and fill gaps between building blocks. Mortars can also be used to fasten existing structures, for example, to replace damaged or eroded portions of the original mortar, among other applications.

[0173] For example, as mentioned above, the method of the present invention is also used in the sequestration of CO2, i.e., CO2 sequestration. "CO2 sequestration" refers to the removal or separation of a quantity of CO2 from a CO2-containing gas, such as a gaseous waste stream produced by an industrial plant, such that at least a portion of the CO2 is not present in the CO2-containing gas after removal. The CO2 sequestration method of the present invention sequesters CO2 and, in some cases, then produces a storage-stable CO2 sequestration product from the quantity of CO2, such that the CO2 produced is sequestered in the product. A storage-stable CO2 sequestration product is a storage-stable composition that incorporates a quantity of CO2 into a storage-stable form, such as a terrestrial storage form or an underwater storage-stable form, such that the CO2 is no longer present as a gas in the atmosphere or is no longer available. Thus, sequestration of CO2 by the method of the present invention results in the prevention of CO2 gas entering the atmosphere, allowing for long-term storage of CO2 in a manner such that the CO2 does not become part of the atmosphere.

[0174] Regardless of the scope of the claims appended hereto, the present invention may be defined by the following clauses. 1. A method for producing a building material, comprising: preparing a carbonate precipitate comprising undifferentiated pluripotent polymorphic precursors; and treating the carbonate precipitate under conditions sufficient to produce a building material. 2. The method of claim 1, wherein the carbonate precipitate is dehydrated. 3. The method of claim 1, wherein the carbonate precipitate is included in a carbonate slurry. 4. The method of claim 3, further comprising drying the carbonate slurry. 5. The method of clause 4, wherein treating the carbonate precipitate under conditions sufficient to produce the building material comprises rehydrating the dried carbonate slurry. 6. The method of any one of the preceding clauses, wherein the carbonate precipitate is comprised of metal carbonate particles. 7. The method of claim 6, wherein the metal carbonate particles are alkaline earth metal carbonate particles. 8. The method according to claim 7, wherein the metal carbonate particles are calcium carbonate particles. 9. The method according to clause 8, wherein the metal carbonate particles are calcium magnesium carbonate particles. 10. The method of any one of the preceding clauses, wherein the polymorphic precursor is an amorphous polymorphic precursor. 11. The method of any one of the preceding clauses, wherein the polymorphic precursor is selected from the group consisting of vaterite precursors, calcite precursors, aragonite precursors, dolomite precursors, and protodolomitic precursors. 12. The method of claim 11, wherein the polymorphic precursor comprises a vaterite precursor. 13. The method of claim 11, wherein the polymorphic precursor comprises a calcite precursor. 14. The method of claim 11, wherein the polymorphic precursor comprises an aragonite precursor. 15. The method of claim 11, wherein the polymorphic precursor comprises a dolomite precursor. 16. The method of claim 11, wherein the polymorphic precursor comprises a protodolomite precursor. 17. The method of any one of the preceding clauses, further comprising combining the carbonate precipitate with a seed structure. 18. The method of claim 17, wherein the seed structure is crystallized. 19. The method of claim 18, wherein the seed structure is selected from calcite, aragonite, vaterite, and dolomite. 20. A method according to any one of clauses 17 to 19, wherein the seed structure is in the range of size from 5 nm to 5 cm. 21. The method of claim 19, wherein the carbonate precipitate contains impurities. 22. The method according to claim 21, wherein the impurities are selected from sludge waste and calcite. 23. The method of any one of clauses 17 to 22, wherein the seed structure comprises a rock or mineral. 24. The method according to claim 23, wherein the rock or mineral is selected from aggregates containing CaCO3, waste concrete, tropical sand, limestone, and fine waste dust. 25. The method of any one of clauses 17 to 24, wherein combining the carbonate precipitate with the seed structure comprises mixing. 26. The method of any one of clauses 17-24, wherein combining the carbonate precipitate with the seed structure comprises coating the seed structure with the carbonate precipitate. 27. The method of any one of clauses 17-24, wherein combining the carbonate precipitate with the seed structure comprises coating the carbonate precipitate with the seed structure. 28. The method of any one of clauses 17 to 27, wherein the combining is carried out before precipitation of the carbonate precipitate. 29. The method of any one of the preceding clauses, wherein treating the carbonate precipitate under conditions sufficient to produce the building material includes maintaining a moisture level of the carbonate precipitate. 30. The method of claim 29, wherein maintaining the moisture level includes preventing evaporation. 31. The method of claim 29, wherein maintaining the moisture level comprises adding water. 32. The method of claim 31, wherein maintaining the moisture level includes cycling between drying and adding water. 33. The method of any one of the preceding clauses, further comprising evaluating the carbonate precipitate for the presence of polymorphic precursors. 34. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of polymorphic precursors comprises assaying the carbonate precipitate by scanning electron microscopy (SEM). 35. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of polymorphic precursors comprises evaluating whether the carbonate precipitate comprises a smooth globular structure. 36. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of polymorphic precursors comprises obtaining an infrared (IR) spectrum of the carbonate precipitate. 37. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of polymorphic precursors comprises collecting a powder X-ray diffraction (XRD) pattern of the carbonate precipitate. 38. The method of claim 37, wherein evaluating the carbonate precipitate for the presence of polymorphic precursors comprises detecting the presence of one or more crystal systems in the carbonate precipitate. 39. The method of claim 36 or 37, wherein evaluating the carbonate precipitate for the presence of polymorphic precursors comprises evaluating whether the pattern exhibits a broad peak. 40. The method of claim 38, wherein evaluating the carbonate precipitate for the presence of a polymorphic precursor comprises evaluating whether the pattern exhibits a peak at 39° 2θ. 41. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of polymorphic precursors comprises obtaining a Ca:C ratio. 42. The method of claim 41, wherein evaluating the carbonate precipitate for the presence of polymorphic precursors comprises evaluating whether the Ca:C ratio indicates Ca deficiency. 43. The method of any one of the preceding clauses, further comprising contacting the building material with sufficient hardening liquid to produce a hardened building material. 44. The method of claim 43, comprising contacting the carbonate precipitate with a hardening liquid. 45. The method of claim 43 or 44, wherein the setting liquid comprises a carbonate setting liquid, a bicarbonate setting liquid, a phosphate setting liquid, a divalent alkaline earth metal setting liquid, or water. 46. ​​The method of any one of clauses 43 to 45, further comprising controlling the temperature of the building material while contacting the building material with the hardening liquid. 47. A method according to any one of the preceding clauses, in which the building material comprises aggregate. 48. The method of claim 47, wherein treating the carbonate precipitate includes combining the carbonate precipitate with an aggregate substrate. 49. The method of claim 47 or 48, wherein treating the carbonate precipitate comprises subjecting the carbonate precipitate to a rotational action. 50.(a) Cement, and (b) Aggregate to produce a concrete dry composite. 51. The method of claim 50, wherein the cement comprises a hydraulic cement. 52. The method of claim 51, wherein the hydraulic cement comprises Portland cement. 53. The method of any one of clauses 50-52, further comprising combining the concrete dry composition with a liquid to produce a settable composition. 54. The method of any one of the preceding clauses, wherein preparing the carbonate precipitate comprises a CO2 sequestration process. 55. The method of claim 54, wherein the CO2 sequestration process comprises contacting the aqueous capture liquid with a gaseous CO2 source under conditions sufficient to produce aqueous carbonate salts. 56. The method of claim 55, further comprising combining a cation source with the aqueous carbonate salt under conditions sufficient to produce a CO2 sequestering carbonate salt. 57. The method of claim 55 or 56, wherein the aqueous capture liquid is an aqueous ammonia capture liquid. 58. Aggregates produced in accordance with any one of clauses 47 to 49. 59. Concrete dry composite produced in accordance with any one of clauses 50 to 52. 60. A concrete dry composite as described in Clause 59 having a compressive strength of not less than 4,000 psi. 61. A solidifiable composition produced according to the method of clause 53. 62. A method of constructing a building structure, the method comprising constructing the building structure using building materials produced in accordance with any one of clauses 1 to 57.

[0175] The following are offered by way of example and not by way of limitation.

[0176] experiment Example 1: 10% (w / w dry basis) aragonite seeds were added to freshly precipitated calcium carbonate. The mixture was cured at high humidity and warmed in a temperature controlled chamber. The final product was obtained when the polymorph was fully transformed into the desired polymorphic structure and reached its final strength. Figure 9 shows data showing the production of aragonite final product using aragonite seeds. It also demonstrates the use of XRD (X-ray diffraction) to characterize the polymorphs in the seeded samples.

[0177] Example 2: The seed structures were combined with calcium carbonate precipitate that was already in solid form. The seed precipitation mixture was then agglomerated to form the desired particle size and shape and cured in a temperature-controlled (warmed at 75° C.) humidity chamber. This was compared to a sample that was treated similarly except that no seeds were added. In other words, the precipitate was agglomerated to the desired particle size and shape and then cured in a temperature-controlled (warmed at 75° C.) humidity chamber (the “negative control” sample). Both samples were then subjected to durability testing, the results of which are shown in FIG. 10. As shown in FIG. 10, an improvement in strength can be observed in the calcium carbonate sample with the addition of the seed structure compared to the same calcium carbonate sample lacking the seed structure.

[0178] Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be readily apparent to those skilled in the art that, in light of the teachings of this invention, certain changes and modifications can be made thereto without departing from the spirit or scope of the appended claims.

[0179] Thus, the above merely illustrates the principles of the present invention. It will be understood that those skilled in the art can devise various arrangements that embody the principles of the present invention and are included within its spirit and scope, although not expressly described or shown herein. Furthermore, all examples and conditional language recited herein are intended primarily to aid the reader in understanding the principles of the present invention and the concepts contributed by the inventor to further advance the art, and should not be construed as being limited to such specifically recited examples and conditions. Furthermore, all statements herein that describe principles, aspects, and embodiments of the present invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, such equivalents are intended to include both currently known equivalents and equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. Thus, the scope of the present invention is not intended to be limited to the exemplary embodiments shown and described herein. Rather, the scope and spirit of the present invention is embodied by the appended claims.

[0180] CROSS-REFERENCE TO RELATED APPLICATIONS Pursuant to 35 U.S.C. §119(e), this application claims priority to the filing date of U.S. Provisional Patent Application No. 63 / 291,767, filed December 20, 2021, the disclosure of which is incorporated herein by reference.

Claims

1. 1. A method of producing a building material, comprising: preparing a carbonate precipitate comprising undifferentiated pluripotent polymorphic precursors; and treating said carbonate precipitate under conditions sufficient to produce said building material.

2. The method of claim 1 , wherein the carbonate precipitate is dewatered.

3. The method of claim 1 , wherein the carbonate precipitate is contained in a carbonate slurry.

4. The method of claim 3 further comprising drying the carbonate slurry.

5. 5. The method of claim 4, wherein treating the carbonate precipitate under conditions sufficient to produce the building material comprises rehydrating the dried carbonate slurry.

6. 10. The method of any one of the preceding claims, wherein the carbonate precipitate consists of metal carbonate particles.

7. The method of claim 6 , wherein the metal carbonate particles are alkaline earth metal carbonate particles.

8. The method of claim 7 , wherein the metal carbonate particles are calcium carbonate particles.

9. The method of claim 8 , wherein the metal carbonate particles are calcium magnesium carbonate particles.

10. 10. The method of any one of the preceding claims, wherein the polymorphic precursor is an amorphous polymorphic precursor.

11. 10. The method of any one of the preceding claims, wherein the polymorphic precursor is selected from the group consisting of vaterite precursors, calcite precursors, aragonite precursors, dolomite precursors, and protodolomite precursors.

12. The method of claim 11 , wherein the polymorphic precursor comprises a vaterite precursor.

13. The method of claim 11 , wherein the polymorphic precursor comprises a calcite precursor.

14. The method of claim 11 , wherein the polymorphic precursor comprises an aragonite precursor.

15. The method of claim 11 , wherein the polymorphic precursor comprises a dolomite precursor.

16. The method of claim 11 , wherein the polymorphic precursor comprises a protodolomite precursor.

17. 2. The method of any one of the preceding claims, further comprising combining the carbonate precipitate with a seed structure.

18. The method of claim 17 , wherein the seed structure is crystallized.

19. 20. The method of claim 18, wherein the seed structures are selected from calcite, aragonite, vaterite, and dolomite.

20. The method according to any one of claims 17 to 19, wherein the seed structure has a size in the range of 5 nm to 5 cm.

21. 20. The method of claim 19, wherein the carbonate precipitate comprises impurities.

22. 22. The method of claim 21, wherein the impurities are selected from sludge waste and calcite.

23. The method of any one of claims 17 to 22, wherein the seed structure comprises a rock or a mineral.

24. The rock or mineral is CaCO ３ 24. The method of claim 23, wherein the aggregate is selected from aggregates comprising: waste concrete, tropical sand, limestone, and fine waste dust.

25. The method of any one of claims 17 to 24, wherein combining the carbonate precipitate with the seed structure comprises mixing.

26. 25. The method of any one of claims 17 to 24, wherein combining the carbonate precipitate with the seed structure comprises coating the seed structure with the carbonate precipitate.

27. 25. The method of any one of claims 17 to 24, wherein combining the carbonate precipitate with the seed structure comprises coating the carbonate precipitate with the seed structure.

28. 28. The method of any one of claims 17 to 27, wherein the combining occurs prior to precipitation of the carbonate precipitate.

29. 2. The method of any one of the preceding claims, wherein treating the carbonate precipitate under conditions sufficient to produce the building material comprises maintaining a moisture level of the carbonate precipitate.

30. 30. The method of claim 29, wherein maintaining the moisture level comprises preventing evaporation.

31. 30. The method of claim 29, wherein maintaining the moisture level comprises adding water.

32. 32. The method of claim 31 , wherein maintaining the moisture level comprises cycling between drying and adding water.

33. 2. The method of any one of the preceding claims, further comprising evaluating the carbonate precipitate for the presence of the polymorphic precursor.

34. 34. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of the polymorphic precursor comprises assaying the carbonate precipitate by scanning electron microscopy (SEM).

35. 34. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of the polymorphic precursor comprises evaluating whether the carbonate precipitate comprises a smooth globular structure.

36. 34. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of the polymorphic precursor comprises obtaining an infrared (IR) spectrum of the carbonate precipitate.

37. 34. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of the polymorphic precursor comprises collecting a powder X-ray diffraction (XRD) pattern of the carbonate precipitate.

38. 38. The method of claim 37, wherein evaluating the carbonate precipitate for the presence of the polymorphic precursors comprises detecting the presence of one or more crystal systems in the carbonate precipitate.

39. 38. The method of claim 36 or 37, wherein evaluating the carbonate precipitate for the presence of the polymorphic precursor comprises evaluating whether the pattern exhibits a broad peak.

40. 40. The method of claim 38, wherein evaluating the carbonate precipitate for the presence of the polymorphic precursor comprises evaluating whether the pattern exhibits a peak at 39° 2θ.

41. 34. The method of claim 33, wherein evaluating the carbonate precipitate for the presence of the polymorphic precursor comprises obtaining a Ca:C ratio.

42. 42. The method of claim 41 , wherein evaluating the carbonate precipitate for the presence of the polymorphic precursor comprises evaluating whether the Ca:C ratio indicates Ca deficiency.

43. 13. The method of any one of the preceding claims, further comprising contacting the building material with sufficient hardening liquid to produce a hardened building material.

44. 44. The method of claim 43, comprising contacting the carbonate precipitate with the hardening liquid.

45. 45. The method of claim 43 or 44, wherein the setting liquid comprises a carbonate setting liquid, a bicarbonate setting liquid, a phosphate setting liquid, a divalent alkaline earth metal setting liquid, or water.

46. 46. ​​The method of any one of claims 43 to 45, further comprising controlling the temperature of the building material during the contacting of the building material with a hardening liquid.

47. 10. The method of any one of the preceding claims, wherein the building material comprises aggregate.

48. 48. The method of claim 47, wherein treating the carbonate precipitate comprises combining the carbonate precipitate with an aggregate substrate.

49. 49. The method of claim 47 or 48, wherein treating the carbonate precipitate comprises subjecting the carbonate precipitate to a rolling action.

50. (a) cement, and (b) The aggregate to produce a concrete dry composite.

51. 51. The method of claim 50, wherein the cement comprises a hydraulic cement.

52. 52. The method of claim 51, wherein the hydraulic cement comprises Portland cement.

53. 53. The method of any one of claims 50 to 52, further comprising combining the concrete dry composition with a liquid to produce a settable composition.

54. Preparing the carbonate precipitate comprises ２ 10. A method according to any one of the preceding claims, comprising a sequestration process.

55. The CO ２ The sequestration process comprises converting the aqueous capture liquid into gaseous CO under conditions sufficient to produce aqueous carbonate salts. ２ 55. The method of claim 54, comprising contacting with a source.

56. CO ２ 56. The method of claim 55, further comprising combining the aqueous carbonate salt with a cation source under conditions sufficient to produce a sequestered carbonate salt.

57. 57. The method of claim 55 or 56, wherein the aqueous capture liquid is an aqueous ammonia capture liquid.

58. 50. An aggregate produced according to any one of claims 47 to 49.

59. A concrete dry composite produced according to any one of claims 50 to 52.

60. 60. The dry concrete composite of claim 59 having a compressive strength of 4,000 psi or greater.

61. 54. A solidifiable composition produced according to the method of claim 53.

62. 58. A method of constructing a building structure, comprising constructing said building structure using the building material produced in accordance with any one of claims 1 to 57.

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