Method and system for preparing concrete precursors

Abstract

To reduce costs or the amount of waste concrete. This specification provides a method and system for preparing a concrete precursor. The method and system include the step of contacting recycled concrete aggregate with an acid to produce the concrete precursor.

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims priority to U.S. Patent Application No. 63 / 452,107, filed on 14 March 2023, the contents of which, including any drawings, are incorporated herein by reference in their entirety.

[0002] (Field of invention) This specification generally relates to a method for preparing concrete precursors from recycled concrete aggregate (RCA). [Background technology]

[0003] Due to accelerating urbanization and industrialization, construction and demolition (C&D) waste, primarily disposed of in landfills, now exceeds 3 billion tons annually. The majority of this C&D waste is concrete. While the generation of waste concrete increases environmental burden and handling costs, the unrestricted development of natural resources such as natural aggregates is leading to a shortage of new construction materials in highly urbanized areas such as Hong Kong. Therefore, attempts have been made to use recycled concrete aggregate (RCA) to reduce waste handling costs and provide additional materials for new construction. However, concrete produced from RCA has significantly lower performance, for example, due to RCA's high water absorption, which substantially limits the use of such materials in structural performance.

[0004] Furthermore, cement production releases large amounts of CO2 into the atmosphere. A key step in cement production is calcination, i.e., CaCO3 → CaO + CO2, which directly produces CO2 as a reaction product and requires considerable energy consumption to maintain the necessary temperature of up to 1,500°C. [Overview of the project]

[0005] This specification provides methods and systems for producing concrete precursors from RCA for use in the manufacture of cement and / or concrete. The systems and methods described herein may have several advantages over conventional methods for producing such building materials, including (e.g.) reducing the use of natural mineral resources, using less energy (e.g., net energy neutrality), generating less CO2 (e.g., carbon neutrality) or even being net carbon negative (e.g., CO2 sequestration), and providing a regeneration process for reusing by-products of the reaction in the reaction.

[0006] Generally, this disclosure relates to processes and systems for preparing concrete precursors from recycled concrete aggregate (RCA).

[0007] Some embodiments provide a method for preparing a concrete precursor, and this method is (a) A step of bringing inorganic solid waste containing one or more metal ions into contact with an acid to produce a concrete precursor and a liquid rich in one or more metal ions, (b) A step of contacting a liquid rich in one or more metal ions with a base to produce a precipitate containing one or more metal ions and a liquid lacking one or more metal ions, (c) A step of regenerating acids and bases by bringing a liquid lacking one or more metal ions into contact with an electrolytic cell, (d) A step of repeating each of steps (a) to (b) at least once using the acid and base from step (c).

[0008] Some embodiments provide a method for preparing a concrete precursor, and this method is (a) A step of contacting recycled concrete aggregate (RCA) containing one or more metal ions with an acid to produce a concrete precursor and a liquid rich in one or more metal ions, (b) Contacting one or more liquids rich in one or more metal ions with a base to produce a precipitate containing one or more metal ions and a liquid deficient in one or more metal ions; (c) Contacting the liquid deficient in one or more metal ions with an electrolytic cell to regenerate an acid and a base; (d) Repeating each of steps (a) to (b) at least once using the acid and base from step (c).

[0009] Some embodiments provide a method of preparing a concrete precursor, the method comprising: (a) Contacting recycled concrete aggregate (RCA) containing one or more metal ions with an acid to produce a concrete precursor and a liquid rich in one or more metal ions; (b) Contacting the liquid rich in one or more metal ions with a base and carbon dioxide to produce a precipitate containing one or more metal carbonates derived from one or more metal ions and a liquid deficient in one or more metal ions; (c) Contacting the liquid deficient in one or more metal ions with an electrolytic cell to regenerate an acid and a base.

[0010] Some embodiments provide a method of preparing a concrete precursor, the method comprising: (a) Contacting recycled concrete aggregate (RCA) containing one or more metal ions with an acid to produce a concrete precursor and a liquid rich in one or more metal ions; (b) Contacting the liquid rich in one or more metal ions with a base containing a carbonate and / or bicarbonate to produce one or more metal carbonates derived from one or more metal ions and a liquid deficient in one or more metal ions; (c) Contacting the liquid deficient in one or more metal ions with an electrolytic cell to regenerate an acid and a base, The carbonate and / or bicarbonate is produced by mixing carbon dioxide and a metal hydroxide.

[0011] Some embodiments provide a method for preparing a concrete precursor, the method comprising: (a) contacting recycled concrete aggregate (RCA) containing one or more metal ions with an acid to produce a concrete precursor and a liquid rich in one or more metal ions; (b) contacting the liquid rich in one or more metal ions with an electrolytic cell to regenerate the acid and produce a precipitate containing one or more metal ions.

[0012] Some embodiments provide a method for preparing a concrete precursor, the method comprising: (a) contacting recycled concrete aggregate (RCA) containing one or more metal ions with an acid within an electrochemical cell to produce a concrete precursor and a liquid rich in one or more metal ions; (b) contacting the liquid rich in one or more metal ions with a base within the electrochemical cell to form a precipitate containing one or more metal ions and a liquid deficient in one or more metal ions, where the electrochemical cell includes an anode reservoir containing an anode and an acid, and a cathode reservoir containing a cathode and a base, and the anode reservoir and the cathode reservoir are separated by a separator.

[0013] Some embodiments provide a system for preparing a concrete precursor, the system comprising: an electrochemical cell configured to prepare a concrete precursor, the electrochemical cell including an anode reservoir containing an anode and an acid, and a cathode reservoir containing a cathode and a base, and the anode reservoir and the cathode reservoir are separated by a separator; A contactor configured to accept recycled concrete aggregate (RCA) containing one or more metal ions into an anode reservoir, wherein the anode reservoir is configured to contact the RCA with an acid to produce a concrete precursor and a liquid rich in one or more metal ions, and the cathode reservoir is configured to contact the liquid rich in one or more metal ions with a base to form a precipitate containing one or more metal ions and a liquid deficient in one or more metal ions. A first filtration system in contact with the anode reservoir, configured to filter and remove concrete precursors from the anode reservoir, The system comprises a second filtration system in contact with a cathode reservoir, configured to filter and remove precipitates from the cathode.

[0014] Other implementations of the above embodiments include corresponding systems, devices, and computer programs configured to perform the operation of the method and encoded on a computer storage device. Details of one or more embodiments of the subject matter described herein are given in the accompanying drawings and the following description. Other features, embodiments, and advantages of the subject matter will become apparent from the description, drawings, and claims.

[0015] In some embodiments, the methods described herein offer significant cost savings compared to current methods for preparing concrete precursors, including methods using RCA. In some embodiments, the methods described herein offer significant reductions in the amount of waste concrete by converting RCA into a valuable resource. [Brief explanation of the drawing]

[0016] [Figure 1A] This specification describes exemplary methods for preparing concrete precursors from recycled concrete aggregates. Ca(OH)2 or other metal hydroxides can be further treated thermally and mechanically to produce cement or auxiliary cementitious materials. [Figure 1B]These are exemplary electrolytic cells that can be used in the method for preparing the concrete precursor shown in Figure 1A as disclosed herein. The anion exchange membrane (AEM) and cation exchange membrane (CEM) can be replaced with bipolar membranes. [Figure 1C] These are exemplary electrolytic cells that can be used in the method for preparing the concrete precursor shown in Figure 1A as disclosed herein. The anion exchange membrane (AEM) and cation exchange membrane (CEM) can be replaced with bipolar membranes. [Figure 1D] These are exemplary electrolytic cells that can be used in the method for preparing the concrete precursor shown in Figure 1A as disclosed herein. The anion exchange membrane (AEM) and cation exchange membrane (CEM) can be replaced with bipolar membranes. [Figure 2] A bipolar membrane electrolytic cell for acid and base generation is shown. This cell configuration can accommodate multiple electrodialysis units. For example, instead of having one electrodialysis unit written as [electrode|CEM|BPM|AEM|CEM|electrode] (as shown), it may have [electrode|CEM|BPM|AEM|CEM|BPM|AEM|CEM|electrode], [electrode|CEM|BPM|AEM|CEM|BPM|AEM|CEM|BPM|AEM|CEM|electrode], or [electrode|CEM(|BPM|AEM|CEM)*n|electrode], which would further reduce the overall cost of electrodialysis. [Figure 3] This specification discloses exemplary methods for preparing concrete precursors from recycled concrete aggregate and CO2, wherein CO2 is added during the base treatment. [Figure 4] This specification discloses exemplary methods for preparing a concrete precursor from recycled concrete aggregate and CO2, wherein CO2 is added to a base to produce an aqueous carbonate. [Figure 5A] This specification discloses an exemplary method for preparing a concrete precursor from recycled concrete aggregate, in which the calcium salt is directly subjected to electrolysis. [Figure 5B]These are exemplary electrolytic cells that can be used in the method for preparing the concrete precursor shown in Figure 5A, as disclosed herein. [Figure 5C] These are exemplary electrolytic cells that can be used in the method for preparing the concrete precursor shown in Figure 5A, as disclosed herein. [Figure 5D] These are exemplary electrolytic cells that can be used in the method for preparing the concrete precursor shown in Figure 5A, as disclosed herein. [Figure 6] This specification discloses an exemplary method for preparing a concrete precursor from recycled concrete aggregate, in which RCA is used directly in an electrolytic cell. [Figure 7] Figure 3 shows an example of the steps for preparing the concrete precursor, in which the electrolysis step is carried out sequentially via electrodistillation as disclosed herein. [Figure 8] Figure 6 shows an example of the steps for preparing the concrete precursor, in which the electrolysis step is carried out sequentially via electrodistillation as disclosed herein. [Figure 9] An example of a batch process electrolysis method that can be used in the method for preparing concrete precursors disclosed herein is shown. [Figure 10] This specification discloses a method for preparing concrete precursors, for example, an example of a continuous base treatment that can be used in the method shown in Figure 1A. [Figure 11] A schematic diagram of a packed-bed reactor (form factor 1) is shown. [Figure 12A] The images show form factor 1 and RCA treated with acid using form factor 1 as described in Example 2. The RCA is filled into a 10-foot-high pipe, and the acid solution is then continuously circulated through the RCA bed by a peristaltic pump. The acid-treated RCA still has a high mortar content. [Figure 12B]The images show form factor 1 and RCA treated with acid using form factor 1 as described in Example 2. The RCA is filled into a 10-foot-high pipe, and the acid solution is then continuously circulated through the RCA bed by a peristaltic pump. The acid-treated RCA still has a high mortar content. [Figure 13] This shows the time course of pH during acid treatment of RCA in a rotating drum (form factor 2) in Example 2. [Figure 14A] In Example 4, photographs of the acid-treated RCA in a rotating drum (form factor 2) after the first, second, and third parts of a continuous acid treatment are shown, respectively. Each photograph was taken 6 hours after treatment. These results indicate that dividing a single acid treatment into multiple intervals improved mortar removal. The average water absorption rate of the aggregate after three treatments (total treatment time of 18 hours) was 0.96 ± 0.1. [Figure 14B] In Example 4, photographs of the acid-treated RCA in a rotating drum (form factor 2) after the first, second, and third parts of a continuous acid treatment are shown, respectively. Each photograph was taken 6 hours after treatment. These results indicate that dividing a single acid treatment into multiple intervals improved mortar removal. The average water absorption rate of the aggregate after three treatments (total treatment time of 18 hours) was 0.96 ± 0.1. [Figure 14C] In Example 4, photographs of the acid-treated RCA in a rotating drum (form factor 2) after the first, second, and third parts of a continuous acid treatment are shown, respectively. Each photograph was taken 6 hours after treatment. These results indicate that dividing a single acid treatment into multiple intervals improved mortar removal. The average water absorption rate of the aggregate after three treatments (total treatment time of 18 hours) was 0.96 ± 0.1. [Figure 15] This shows the time course of pH during acid treatment of RCA in a rotating drum (form factor 2) in Example 4. The first section is the top, the second section is the middle, and the third section is the bottom. [Figure 16]The results of treating RCA with various acids are shown in relation to the water absorption rate of the recovered aggregate. After acid treatment, the water absorption rate decreased by approximately 80%. HCl was the most effective acid for removing the mortar. [Figure 17] This shows the water absorption levels of unused aggregate, untreated RCA, and RCA treated with HCl. RCA treated with HCl has a water absorption value close to that of unused aggregate, providing recovered aggregate that is well within the range of industrial requirements. [Figure 18] Using three multi-batch processing arms (3-batch and 6-batch rotating drums), the water absorption rates of untreated and treated RCA were shown using form factors 1-3. Multi-batch experiments used slightly less acid than stoichiometric amounts and shorter reaction times (18 hours vs. 24 hours). 10 kg of RCA occupied approximately 20% of the volume in the drum reactor. [Figure 19A] The present invention exhibits a form factor 3, including a rotating drum reactor with inlet and outlet ports that allow for continuous circulation of the HCl solution within the reactor at a level just sufficient to process the RCA while minimizing the volume of the solution. [Figure 19B] The present invention exhibits a form factor 3, including a rotating drum reactor with inlet and outlet ports that allow for continuous circulation of the HCl solution within the reactor at a level just sufficient to process the RCA while minimizing the volume of the solution. [Figure 20] The diagram shows a base reaction titration in which NaOH was added to the reacted acid (e.g., an acid solution previously used to treat RCA) to precipitate Ca(OH)2 and other metal hydroxides and / or carbonates. The degree of precipitation increased with pH. [Figure 21A] The images show trays containing cement precursors obtained before and after drying, after treating 5 kg of RCA with acid and then with NaOH on a scale. [Figure 21B] The images show trays containing cement precursors obtained before and after drying, after treating 5 kg of RCA with acid and then with NaOH on a scale. [Figure 22]This document outlines combinations of acid treatment, base reaction, filtration, drying, calcination, and blending to obtain cement precursors suitable for use in cement manufacturing. [Figure 23] Photographs of RCA cement precursors in various states are shown. 23A shows an uncalcined RCA cement precursor. 23B shows calcined RCA cement without additives. 23C shows a calcined RCA cement blend (10g of dried recovered solids + 4.8g of CaO + 1g of SiO2). [Figure 24] The results of compression tests on cement cylinders prepared from RCA cement blends, compared to standard cement types I, II, and V, are shown. [Figure 25] The cement phase composition of cement prepared from recovered cement precursors obtained by treating fresh, unreacted cement with HCl, then NaOH, then calcined at 1450°C, and then blended with 4% gypsum is shown. The results indicate that good mineralogical replication can be achieved in the overall process. [Figure 26A] The results of compression tests on cement cylinders of types I to V cement, along with cylinders derived from recovered cement and RCA cement, are shown. A mortar paste was prepared by mixing 1 part of each cement sample with 3 parts silica sand and 0.5 parts water, and then placed into a cylinder mold. After 3 days of hardening, the cylinder was demolded. The compressive strength of the cylinder was evaluated using a custom-made test apparatus shown in Figure 26A. Cement containing 30% recovered cement showed strength equivalent to type I cement. RCA-derived cement (30% RCA recovered cement and 4% gypsum) showed lower strength. "HL" indicates acid-treated solids. [Figure 26B]The results of compression tests on cement cylinders of types I to V cement, along with cylinders derived from recovered cement and RCA cement, are shown. A mortar paste was prepared by mixing 1 part of each cement sample with 3 parts silica sand and 0.5 parts water, and then placed into a cylinder mold. After 3 days of hardening, the cylinder was demolded. The compressive strength of the cylinder was evaluated using a custom-made test apparatus shown in Figure 26A. Cement containing 30% recovered cement showed strength equivalent to type I cement. RCA-derived cement (30% RCA recovered cement and 4% gypsum) showed lower strength. "HL" indicates acid-treated solids. [Figure 27] The compressive strength of concrete test cylinders prepared using RCA and recycled concrete aggregate obtained by treating RCA with HCl as disclosed herein is shown. The concrete cylinders increased in strength by 10% after 7 and 14 days of hardening. Cylinders prepared using treated RCA (recycled concrete aggregate, inset) showed significantly higher compressive strength than concrete cylinders prepared from untreated RCA. [Figure 28] The H-cell electrolytic cell is shown using an anion exchange membrane FAA-3-PK-74 with a 1cm² carbon cloth electrode doped with 1cm² of Pt, and using voltages of approximately 10V at 50mA and approximately 5V at 10mA. After 60 minutes, the cathode reservoir was observed to turn purple due to base formation, and the anode reservoir was observed to turn clear (pH=2). [Figure 29] This shows the galvanostat (constant current) voltage performance of H-cells composed of different electrodes (area 1 cm², current density 5 mA / cm²). The two carbon electrodes showed an increase in voltage, but the Pt electron electrode remained at a constant voltage. [Figure 30A] The images show a dirty carbon electrode and a fully functional Pt electrode, both covered with a Ca(OH)2 shell, respectively. [Figure 30B] The images show a dirty carbon electrode and a fully functional Pt electrode, both covered with a Ca(OH)2 shell, respectively. [Figure 31]The effect of hydrogen flow rate on current in the hydrogen looping cell of Example 10 is shown. The voltage was constant at 1.3V. The hydrogen flow rates were 10, 20, 30, and 50 mL / min (transition points are marked with vertical lines). [Figure 32] The effect of hydrogen flow rate on current in the hydrogen looping cell of Example 10 is shown. 100 mV / s, 0-2.5 volts. The hydrogen flow rate on the upper line is 30 mL / min, and the hydrogen flow rate on the lower line is 0 mL / min (no hydrogen). [Figure 33] This shows the voltage stability of a hydrogen looping cell with an AEM (FAB-PK-130 membrane), a Ni mesh cathode, and a carbon cloth W1S1011 anode with 4 mg / cm2 Pt black. The hydrogen flow rates were 30 mL / min, 100 mV / s, 0.8 V~1.2 V, 1.4, 1.6, 1.8, and 2 V (21 cycles each). [Figure 34] This study describes the voltage stability of a hydrogen looping cell with an AEM (FAB-PK-130 membrane), a Ni mesh cathode, and a Pt-Ti mesh anode. The hydrogen flow rates were 30 mL / min, 100 mV / s, and voltages of 0.8V~1.2V, 1.4V, 1.6V, 1.8V, and 2V (11 cycles each). The current through the Pt-Ti mesh was one-tenth that of the Pt-carbon cloth anode. [Figure 35] This shows a constant voltage run (1.4V) of 536.028mAh in a hydrogen looping cell with a Ni mesh cathode and 4mg / cm2Pt black on a carbon cloth W1S1011 anode, with an AEM (FAB-PK-130 membrane) and a hydrogen flow of 30mL / min. This run corresponded to the production of 0.2M NaOH. The current decreased over time, indicating instability. NaOH Faraday efficiency = 82%, 1.14kWh / kg NaOH; average 53mA / cm2 at 1.4V. [Figure 36]This shows a constant voltage run (1.4V) in a hydrogen looping cell with an AEM (FAB-PK-130 membrane) and a hydrogen flow of 30 mL / min, a Ni mesh cathode, and 2 mg / cm2 Pt black on a carbon cloth W1S1011 anode. The amount of Pt added was half that of Figure 35, and the current was one-tenth. These results indicate that the amount of Pt added has a significant effect on the hydrogen oxidation reaction rate. [Figure 37] The energy cost for producing NaOH using the in-house manufactured chloro-alkali cell of Example 11 is shown. [Figure 38] The current sweep experiment using the chloro-alkaline cell of Example 11 is shown. Currents of 1, 10, 20, 40, 60, 80, and 100 mA / cm2 were applied. Sweeping to high current densities resulted in cell instability. [Figure 39A] The following shows a comparison between hydrogen looping and chloro-alkaline cells in terms of NaOH Faraday efficiency, NaOH energy cost, and cell voltage. Hydrogen looping is likely to achieve an NaOH output of 1 kWh / kg, but the current density remains uncertain. [Figure 39B] The following shows a comparison between hydrogen looping and chloro-alkaline cells in terms of NaOH Faraday efficiency, NaOH energy cost, and cell voltage. Hydrogen looping is likely to achieve an NaOH output of 1 kWh / kg, but the current density remains uncertain. [Figure 39C] The following shows a comparison between hydrogen looping and chloro-alkaline cells in terms of NaOH Faraday efficiency, NaOH energy cost, and cell voltage. Hydrogen looping is likely to achieve an NaOH output of 1 kWh / kg, but the current density remains uncertain. [Modes for carrying out the invention]

[0017] To facilitate understanding of the disclosures contained herein, several additional terms are defined below. In general, the nomenclature and procedures described herein are well known and commonly used in the art. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. Each of the patents, applications, published applications, and other publications referenced throughout this specification and its accompanying appendices is incorporated herein by reference in their entirety.

[0018] When referring to a number or numerical range, the term "approximately" means that the number or numerical range mentioned is an approximation within, for example, the range of experimental variability and / or statistical experimental error, and therefore the number or numerical range may vary by up to ±10% of the stated number or numerical range.

[0019] As used herein, the term “regeneration” refers to a step in a process in which the products of a particular step in the process are used as reactants or starting materials in another step of the process. For example, if compound A is formed from the reaction of compound C and X, then one of the products of reaction A + B → C + D, compound C, can further react with X to provide A, which is the starting material for the A + B reaction.

[0020] As used herein, the term “electrochemical cell” refers to a device and / or device component that performs electrochemistry. An electrochemical cell has two or more electrodes (e.g., a cathode and an anode) and one or more electrolytes and may be configured with or without a separator, as described herein.

[0021] As used herein, the term “cement” refers to hydraulic cement and non-hydraulic cement, as well as combinations thereof. Exemplary cements include, but are not limited to, ordinary Portland cement (OPC), Portland pozzolanic cement (PPC), fast-setting cement, ultrafast-setting cement, low-temperature cement, and rapid-setting cement. Such cements can be mixed with other materials, such as coarse or fine aggregate, to produce mortar and / or concrete materials.

[0022] As defined herein, the term "separator" refers to a material located between the cathode reservoir and the anode reservoir in an electrochemical cell. Typical separators include, but are not limited to, cation exchange membranes and anion exchange membranes.

[0023] The terms "electro-distillation" and "electrodistillation" are used interchangeably herein and refer to an electrochemical process that separates different materials spatially across many linked cells or temporally within a single cell by differences in cell pH and / or cell voltage, similar to conventional distillation columns that separate materials by boiling point. In constant-current electrolysis (i.e., continuous electrodistillation), the voltage remains constant while one species is precipitating, and then rapidly increases until another species begins to precipitate.

[0024] The term “concrete precursor” refers to cement and natural aggregates filtered from inorganic waste (e.g., recycled concrete aggregate) and / or produced by the methods disclosed herein, including, but not limited to, stone, gravel, sand, silt, clay, etc. Cement is produced from precipitates from a base reaction, as disclosed herein.

[0025] The term “liquid rich in” provided through this disclosure is intended to mean that the liquid contains the above-mentioned component at a concentration of at least 0.1 M. For example, the term “liquid rich in one or more metal ions” refers to a liquid having a concentration of one or more metal ions at at least 0.1 M (e.g., 0.1 M to 5 M).

[0026] The term “liquid lacking a component” as provided through this disclosure is intended to mean that the liquid contains the above component at a concentration of less than 0.1 M. For example, the term “liquid lacking one or more metal ions” refers to a liquid having a concentration of one or more metal ions at less than 0.1 M (e.g., in the range of 0.0001 to 0.09 M).

[0027] Some embodiments provide a method for preparing a concrete precursor, and this method is (a) A step of contacting inorganic solid waste containing one or more metal ions with an acid to produce a concrete precursor and a liquid rich in one or more metal ions, (b) A step of contacting a liquid rich in one or more metal ions with a base to produce a precipitate containing one or more metal ions and a liquid lacking one or more metal ions, (c) A step of regenerating acids and bases by bringing a liquid lacking one or more metal ions into contact with an electrolytic cell, (d) A step of repeating each of steps (a) to (b) at least once using the acid and base from step (c).

[0028] In some embodiments, inorganic solid waste includes one or more of the following: recycled concrete aggregate (RCA), smelting slag, blast furnace slag, incinerator bottom ash, and electronic equipment waste (e.g., batteries, solar cells, and other electronic devices). In some embodiments, inorganic solid waste includes recycled concrete aggregate (RCA). In some embodiments, inorganic solid waste includes smelting slag. In some embodiments, inorganic solid waste includes blast furnace slag. In some embodiments, inorganic solid waste includes incinerator bottom ash. In some embodiments, inorganic solid waste includes batteries (e.g., recycled and / or shredded batteries). In some embodiments, inorganic solid waste includes solar cells (e.g., recycled and / or shredded solar cells). In some embodiments, inorganic solid waste includes electronic equipment (e.g., recycled and / or shredded electronic equipment). In some embodiments, inorganic solid waste includes combinations of recycled concrete aggregate (RCA), smelting slag, blast furnace slag, incinerator bottom ash, batteries, solar cells, and electronic equipment.

[0029] In some embodiments, the RCA contains approximately 1% to approximately 25% w / w of CaO, for example, approximately 2% to approximately 20%, approximately 3% to approximately 15%, approximately 4% to approximately 10%, approximately 5% to approximately 9%, approximately 6% to approximately 8%, approximately 7% to approximately 8%, approximately 1% to approximately 10%, approximately 2% to approximately 15%, approximately 3% to approximately 12%, approximately 4% to approximately 10%, approximately 5% to approximately 10%, approximately 6% to approximately 10%, approximately 7% to approximately 10%, approximately 8% to approximately 10%, and approximately 8% to approximately 9%.

[0030] Some embodiments provide a method for preparing a concrete precursor, and this method is (a) A step of contacting recycled concrete aggregate (RCA) containing one or more metal ions with an acid to produce a concrete precursor and a liquid rich in one or more metal ions, (b) A step of contacting a liquid rich in one or more metal ions with a base to produce a precipitate containing one or more metal ions and a liquid lacking one or more metal ions, (c) A step of regenerating acids and bases by bringing a liquid lacking one or more metal ions into contact with an electrolytic cell, (d) A step of repeating each of steps (a) to (b) at least once using the acid and base from step (c).

[0031] In some embodiments, the electrolytic cell is a single-membrane electrolytic cell, a two-membrane salt decomposition electrolytic cell, a multi-membrane salt decomposition electrolytic cell, a chlorine-alkali electrolytic cell, a bipolar membrane electrodialysis electrolytic cell, or any combination of the above.

[0032] Some embodiments provide a method for preparing a concrete precursor, and this method is (a) A step of contacting recycled concrete aggregate (RCA) containing one or more metal ions with an acid to produce a concrete precursor and a liquid rich in one or more metal ions, (b) A step of contacting a liquid rich in one or more metal ions with a base and carbon dioxide to produce a precipitate containing one or more metal carbonates derived from one or more metal ions and a liquid lacking one or more metal ions, (c) A step of regenerating acids and bases by bringing a liquid lacking one or more metal ions into contact with an electrolytic cell.

[0033] In some embodiments, step (b) includes sequentially contacting a liquid rich in one or more metal ions with two or more independently selected bases. In some embodiments, the bases are the same. In some embodiments, the bases are different. In some embodiments, each base contains an independently selected metal hydroxide.

[0034] In some embodiments, carbon dioxide is provided as a composition, the composition comprising carbon dioxide and at least one additional gas as described herein. For example, some embodiments described herein utilize carbon dioxide to produce, for example, metal carbonates or bicarbonates from metal hydroxides. In some embodiments, the carbon dioxide composition includes a concentrated carbon dioxide source (e.g., flue gas from a power plant). In some embodiments, the carbon dioxide composition includes a diluted carbon dioxide source (e.g., atmospheric carbon dioxide). In other words, some embodiments described herein include carbon dioxide removal and sequestration.

[0035] In some embodiments, the composition contains carbon dioxide in amounts ranging from about 0.01% to about 99.9% by weight, or from about 0.01% to about 1.5% by weight, or from about 1% to about 20% by weight, or from about 5% to about 20% by weight, or from about 50% to about 90% by weight. In some embodiments, the composition contains carbon dioxide in amounts ranging from about 0.01% to about 99.9% by weight. In some embodiments, the composition contains carbon dioxide in amounts ranging from about 0.01% to about 1.5% by weight. In some embodiments, the composition contains carbon dioxide in amounts ranging from about 1% to about 10% by weight. In some embodiments, the composition contains carbon dioxide in amounts ranging from about 50% to about 90% by weight.

[0036] In some embodiments, the carbonate and / or bicarbonate is selected from sodium, potassium, lithium, and any combination thereof. In some embodiments, the salt is sodium carbonate, potassium carbonate, lithium carbonate, or any combination thereof. In some embodiments, the salt is sodium bicarbonate, potassium bicarbonate, lithium bicarbonate, or any combination thereof.

[0037] Some embodiments provide a method for preparing a concrete precursor, and this method is (a) A step of contacting recycled concrete aggregate (RCA) containing one or more metal ions with an acid to produce a concrete precursor and a liquid rich in one or more metal ions, (b) A step of bringing a liquid rich in one or more metal ions into contact with an electrolytic cell to regenerate the acid and produce a precipitate containing one or more metal ions.

[0038] In some embodiments, sequential electrolysis occurs via continuous electrodistillation. In some embodiments, sequential electrolysis includes continuous electrodistillation. In some embodiments, sequential electrolysis is continuous electrodistillation.

[0039] Some embodiments provide a method for preparing a concrete precursor, and this method is (a) A step of bringing recycled concrete aggregate (RCA) containing one or more metal ions into contact with an acid in an electrochemical cell to produce a concrete precursor and a liquid rich in one or more metal ions, (b) A step of contacting a liquid rich in one or more metal ions with a base in an electrochemical cell to form a precipitate containing one or more metal ions and a liquid lacking one or more metal ions, An electrochemical cell comprises an anode reservoir containing an anode and an acid, and a cathode reservoir containing a cathode and a base, with the anode reservoir and cathode reservoir separated by a separator.

[0040] In some embodiments, the separator is an anion exchange membrane or a cation exchange membrane. In some embodiments, the separator is an anion exchange membrane. In some embodiments, the separator is a cation exchange membrane.

[0041] In some embodiments, sequential electrolysis occurs via continuous electrodistillation. In some embodiments, sequential electrolysis includes continuous electrodistillation. In some embodiments, sequential electrolysis is continuous electrodistillation.

[0042] In some embodiments, the electrochemical cell comprises an anode reservoir containing an anode and an acid, and a cathode reservoir containing a cathode and a base, wherein the anode reservoir and the cathode reservoir are separated by a separator, and the electrochemical cell is A contactor configured to accept recycled concrete aggregate (RCA) containing one or more metal ions into an anode reservoir, wherein the anode reservoir is configured to contact the RCA with an acid to produce a concrete precursor and a liquid rich in one or more metal ions, and the cathode reservoir is configured to contact the liquid rich in one or more metal ions with a base to form a precipitate containing one or more metal ions and a liquid deficient in one or more metal ions. A first filtration system in contact with the anode reservoir, configured to filter and remove concrete precursors from the anode reservoir, The system includes a second filtration system in contact with a cathode reservoir, configured to filter and remove precipitates from the cathode.

[0043] In some embodiments, the first filtration system is further configured to filter a liquid rich in one or more metal ions from a concrete precursor and feed the liquid rich in one or more metal ions into a cathode reservoir.

[0044] In some embodiments, the separator is an anion exchange membrane or a cation exchange membrane. In some embodiments, the separator is an anion exchange membrane. In some embodiments, the separator is a cation exchange membrane.

[0045] In some embodiments, one or more metal ions are selected from ions of lithium, sodium, potassium, beryllium, magnesium, calcium, strontium, barium, radium, aluminum, gallium, indium, tin, thallium, lead, bismuth, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, cadmium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, and mercury. In some embodiments, one or more metal ions are ion pairs with one or more hydroxide anions that form a metal hydroxide (e.g., Ca(OH)2).

[0046] In some embodiments, one or more metal ions are selected from sodium, potassium, magnesium, calcium, tin, lead, iron, cobalt, nickel, copper, zinc, palladium, silver, cadmium, platinum, and gold ions.

[0047] In some embodiments, one or more metal ions are selected from sodium, potassium, magnesium, and calcium ions.

[0048] In some embodiments, a metal hydroxide (e.g., Ca(OH)2) is further treated thermally and mechanically with additional cement-based materials to form cement.

[0049] Some embodiments include, (a) A step of mixing the precipitate with one or more silicates to form a mixture, (b) A step of grinding the mixture to form fine particles, (c) The process further includes heating fine particles to approximately 1,000°C to approximately 1,500°C for a certain period of time to provide cement.

[0050] In some embodiments, one or more metal hydroxides described herein (e.g., calcium hydroxide) are mixed with a material obtained from one of the filtration steps described herein (referred to herein as a filtration product). In some embodiments, these filtration products include silica and / or silicates. In some embodiments, the silica and / or silicates are ground or milled (e.g., to form nanosilica) before being mixed with one or more metal hydroxides. In some embodiments, the mixture of the filtration product and one or more metal hydroxides is milled or ground to produce nanoparticle material.

[0051] In some embodiments, one or more metal hydroxides described herein (e.g., calcium hydroxide) are mixed with CaO and / or SiO2. In some embodiments, additional materials, including but not limited to Al2O3, CaCO3, MgO, MgCO3, Fe2O3, or Li2CO3, are mixed with the hydroxide precipitate.

[0052] In some embodiments, the nanoparticle material is then subjected to firing temperatures of about 500°C and about 1,450°C (i.e., clinking). In some embodiments, the firing temperatures are about 500°C and about 1,200°C, or about 500°C and about 1,000°C. In some embodiments, the firing temperatures are about 1,000°C to about 1,500°C, for example, about 1,200°C to about 1,500°C, or 1,250°C to about 1,450°C.

[0053] In some embodiments, the nanoparticle material is subjected to firing temperatures for about 20 minutes to about 5 hours, for example, about 30 minutes to about 4 hours, about 45 minutes to about 3 hours, about 1 hour to about 2 hours, about 1 hour to about 1.5 hours, or about 45 minutes to about 1.5 hours. In some embodiments, the nanoparticle material is subjected to firing temperatures for about 1 hour.

[0054] In some embodiments, the nanoparticle material is subjected to a firing temperature that gradually increases, for example, starting at about 100°C for a set period and ending at the maximum temperature. In some embodiments, the time course of firing the nanoparticle material is carried out in substantially the same manner as shown in Table 6 of Example 9.

[0055] In some embodiments, the energy for grinding or milling is provided by green electricity.

[0056] In some embodiments, the performance and operation of the methods described herein are carbon neutral.

[0057] In some embodiments, the nanoparticle material is subjected to firing (i.e., clinked / sintered) and then blended with gypsum. In some embodiments, the amount of gypsum is about 1 to about 10% w / w, for example, about 2% to about 8%, about 3% to about 6%, or about 4% to about 5%.

[0058] A method disclosed herein may include the steps of (a) contacting calcium-containing recycled concrete aggregate (RCA) with an acid to produce a concrete precursor and a calcium-rich liquid; (b) contacting the calcium-rich liquid with a base to produce a calcium precipitate (e.g., calcium hydroxide) and a calcium-deficient liquid; and (c) contacting the calcium-deficient liquid with an electrolytic cell to regenerate the acid and base. In some embodiments, the method may include step (d), which includes repeating each of steps (a) to (b) at least once using the acid and base from step (c). A method disclosed herein may include the steps of (a) contacting calcium-containing recycled concrete aggregate (RCA) with an acid to produce a concrete precursor and a calcium-rich liquid; (b) contacting the calcium-rich liquid with a base and carbon dioxide to produce calcium carbonate and a calcium-deficient liquid; and (c) contacting the calcium-deficient liquid with an electrolytic cell to regenerate the acid and base. The method disclosed herein may include (a) contacting calcium-containing recycled concrete aggregate (RCA) with an acid to produce a concrete precursor and a calcium-rich liquid; (b) contacting the calcium-rich liquid with a base containing a carbonate and / or bicarbonate to produce calcium carbonate and a calcium-deficient liquid; and (c) contacting the calcium-deficient liquid with an electrolytic cell to regenerate the acid and base, wherein the carbonate and / or bicarbonate is produced by mixing carbon dioxide and a metal hydroxide. The method disclosed herein may include (a) contacting calcium-containing recycled concrete aggregate (RCA) with an acid to produce a concrete precursor and a calcium-rich liquid; and (b) contacting the calcium-rich liquid with an electrolytic cell to regenerate the acid and produce a calcium precipitate.The method disclosed herein may include (a) contacting calcium-containing recycled concrete aggregate (RCA) with an acid in an electrochemical cell to produce a concrete precursor and a calcium-rich liquid, and (b) contacting the calcium-rich liquid with a base in an electrochemical cell to form a calcium precipitate and a calcium-deficient liquid, wherein the electrochemical cell comprises an anode reservoir containing an anode and an acid, and a cathode reservoir containing a cathode and a base, and the anode reservoir and the cathode reservoir are separated by a separator.

[0059] Furthermore, systems for preparing concrete precursors are also provided herein. In some embodiments, the system may include an electrochemical cell configured to prepare a concrete precursor, the electrochemical cell comprising an anode reservoir containing an anode and an acid, and a cathode reservoir containing a cathode and a base, the anode reservoir and the cathode reservoir being separated by a separator, and a contactor configured to feed calcium-containing recycled concrete aggregate (RCA) into the anode reservoir, the anode reservoir being configured to contact the RCA with an acid to produce a concrete precursor and a calcium-rich liquid, and the cathode reservoir being configured to contact the calcium-rich liquid with a base to form a calcium precipitate and a calcium-deficient liquid, and a first filtration system in contact with the anode reservoir configured to filter and remove the concrete precursor from the anode reservoir, and a second filtration system in contact with the cathode reservoir configured to filter and remove the calcium precipitate from the cathode.

[0060] In some embodiments, the cement contains calcium oxide. In some embodiments, the cement contains calcium hydroxide.

[0061] In some embodiments, the cement further comprises one or more additional materials, including but not limited to silicates, silicon dioxide, iron oxide, aluminum oxide, aluminates (e.g., tricalcium aluminate), and other minerals.

[0062] Figure 1 shows an exemplary method for preparing a concrete precursor, such as calcium hydroxide, from RCA. This method may include three steps: (1) acid treatment, (2) base treatment, and (3) an electrolytic cell for the regeneration of the acid and base. Applicable acids, bases, salts, and mortar materials include, but are not limited to, HCl, NaOH, NaCl, and Ca(OH)2, as shown in Figure 1.

[0063] Acid treatment: RCA is reacted with acid at a controlled temperature and under stirring. The hardened mortar on the surface of the RCA, containing metal hydroxides such as Ca(OH)2 and metal oxides such as CaO, is dissolved by the acid to form a calcium-rich liquid. Natural aggregates, including metal aluminosilicates, remain undissolved to form a concrete precursor. After acid treatment, the mixture of the concrete precursor and the calcium-rich liquid is filtered. The precipitate can then be washed and sieved. In some embodiments, the aggregate remaining on a #4 sieve, e.g., the concrete precursor, is the recovered coarse natural aggregate.

[0064] Some embodiments described herein provide methods for removing mortar from RCA using the methods described herein.

[0065] In some embodiments, the concrete precursor has a water absorption coefficient as low as that of unused aggregate. In some embodiments, the concrete precursor has a water absorption rate of less than about 3% w / w, for example, less than 2.5%, less than 2%, less than 1.5%, or less than 1%. In some embodiments, the concrete precursor has a water absorption rate of about 0.1% w / w to about 2.5% w / w. In some embodiments, the concrete precursor has a water absorption rate of about 0.5% w / w to about 2.5% w / w. In some embodiments, the concrete precursor has a water absorption rate of about 0.1% w / w to about 2% w / w. In some embodiments, the concrete precursor has a water absorption rate of about 0.5% w / w to about 2% w / w. In some embodiments, the concrete precursor has a water absorption rate of about 0.1% w / w to about 1.5% w / w. In some embodiments, the concrete precursor has a water absorption rate of about 0.5% w / w to about 1.5% w / w. In some embodiments, the concrete precursor has a water absorption rate of about 1% w / w to about 2% w / w.

[0066] The particles that pass through the #4 sieve become a mixture of fine aggregate and silica gel, which can also be used as a raw material for various purposes. A variety of acids, including but not limited to H2SO4, HCl, HNO3, HBr, HI, acetic acid, H3PO4, formic acid, and maleic acid, can be used in the acid treatment step for the methods disclosed herein. The acid concentration can vary from 0.05 M to 30 M.

[0067] In some embodiments, the acid is HCl. In some embodiments, the HCl has concentrations of about 0.2 M to about 5 M, for example, about 0.3 M to about 4 M, about 0.4 M to about 3 M, about 0.5 M to about 2 M, and about 0.5 M to about 1 M.

[0068] To ensure a sufficient reaction, any type of stirring / agitation method may be applied. In situ detection, including but not limited to pH, conductivity, atomic absorption spectroscopy, NMR spectroscopy, and ICP-OES, can be performed in this process, thereby enabling real-time monitoring and feedback control of the reaction progress. In some embodiments, the acid reaction with RCA occurs in a reactor of form factor 1. In some embodiments, the acid reaction with RCA occurs in a reactor of form factor 2. In some embodiments, the acid reaction with RCA occurs in a reactor of form factor 2, and a continuous acid treatment is used. In some embodiments, the continuous acid treatment is 2 to 10 in total, for example, 2 to 8, 2 to 7, 2 to 6, 2 to 5, 2 to 4, 3 to 9, 3 to 8, 3 to 7, 3 to 6, 3 to 5, 3 to 4, 4 to 8, 4 to 7, 4 to 6, 4 to 5. In some embodiments, the acid reaction with RCA occurs in a reactor of form factor 3.

[0069] In some embodiments, the acid reaction with RCA occurs over periods of approximately 1 to 48 hours, for example, approximately 2 to 46 hours, approximately 3 to 42 hours, approximately 4 to 40 hours, approximately 12 to 24 hours, approximately 1 to 2 hours, approximately 1 to 6 hours, approximately 1 to 12 hours, approximately 1 to 24 hours, approximately 1 to 36 hours, and approximately 24 to 48 hours.

[0070] Base treatment: The calcium-rich liquid from the acid treatment is filtered, for example, filtration 1 in Figure 1A, and then mixed with a base (e.g., a base solution). The calcium-rich liquid may contain calcium salts formed during the acid treatment (e.g., one or more of CaCl2, CaSO4, and Ca(NO3)2), as well as one or more of MgCl2, FeCl2, FeCl3, MgSO4, Ca(NO3)2, and Mg(NO3)2. The calcium-rich liquid reacts to form a calcium precipitate (e.g., calcium hydroxide) containing, but not limited to, Ca(OH)2, Mg(OH)2, Fe(OH)2, Fe(OH)3, and Al(OH)3, which precipitates from the solution. The calcium precipitate (e.g., metal hydroxide) is filtered out of the solution, leaving a calcium-deficient liquid. It has been found that different metal hydroxides can precipitate at different pH levels. Therefore, implementing in situ detection allows for better monitoring of the reaction progress and easier separation of different products. Similar to the acid treatment step, a wide variety of bases can be used in this step at different concentrations.

[0071] In some embodiments, the base concentration is approximately 0.2 M to 5 M, for example, approximately 0.3 M to 4 M, approximately 0.4 M to 3 M, approximately 0.5 M to 2 M, and approximately 0.5 M to 1 M.

[0072] In some embodiments, the base is NaOH. In some embodiments, the concentration of NaOH is about 0.2 M to about 5 M, for example, about 0.3 M to about 4 M, about 0.4 M to about 3 M, about 0.5 M to about 2 M, or about 0.5 M to about 1 M.

[0073] In some embodiments, the pH after treating the calcium-rich liquid with a base is about 10 to about 14, for example, about 11 to about 14, about 12 to about 14, and about 13 to about 14.

[0074] Electrolysis: After filtration following base treatment, the calcium-deficient liquid from filtration 2 shown in Figure 1A has a high salt concentration (one or more of LiCl, NaCl, KCl, Li2SO4, Na2SO4, K2SO4, LiNO3, NaNO3, and KNO3, etc.). The calcium-deficient liquid is fed into an electrolytic cell to produce the acid and base used in steps 1 and 2, respectively. Several cell structures and electrolysis strategies can be implemented here. Some examples are described below.

[0075] Figure 1B shows a two-membrane salt decomposition cell that can be used in the method shown in Figure 1A, where the oxidation of water occurs on the anode side, i.e., H2O → 1 / 2O2 + 2H + +2e - This occurs, and water is reduced on the cathode side, i.e., 2H2O + 2e - →H2+2OH - The electrolytic cell may include an anion exchange membrane (AEM) and a cation exchange membrane (CEM), as shown in Figure 1B. In some embodiments, the AEM and CEM can be replaced with bipolar membranes. A calcium-deficient liquid can be supplied to the central reservoir. When a sufficiently large voltage is applied to the electrodes, a water splitting reaction occurs. At the anode, water is oxidized to oxygen, anions are drawn out of the central reservoir, and as a result, an acid solution is produced in the anode electrolyte. Meanwhile, at the cathode, water is reduced to hydrogen, cations are drawn out of the central reservoir, and a basic electrolyte is produced in the cathode reservoir. The thermodynamic voltage for this reaction is 1.23V. Furthermore, a possible auxiliary device for this setup is an H2+O2 fuel cell, which can cover part of the electricity cost.

[0076] Figure 1C shows a slightly modified version of the two-membrane salt decomposition cell that can be used in the method shown in Figure 1A. Instead of water reduction on the cathode side, oxygen reduction is performed, i.e., 1 / 2O2 + 2H2O + 2e - →2OH -Utilize it to circulate O2 gas between the anode and the cathode sides. The voltage difference between the anode and the cathode is smaller (from 0 V to about 0.8 V depending on the pH gradient), which can reduce the energy cost during electrolysis.

[0077] Figure 1D shows an additional electrolytic cell that can be used in the method shown in Figure 1A. Instead of water oxidation on the anode side, hydrogen oxidation, i.e., H2 → 2H + + 2e - is utilized. Hydrogen is circulated internally. The voltage difference between the anode and the cathode is smaller, which can reduce the energy cost during electrolysis.

[0078] Another possible electrolytic cell that can be used in the method shown in Figure 1A is a classical chlor-alkali electrolytic cell. The cation exchange membrane separates the anode side from the cathode side. During electrolysis, chloride ions are oxidized to chlorine at the anode (i.e., 2Cl - → Cl2 + 2e - ), and water is reduced to hydrogen at the cathode. The fuel cell is required to convert hydrogen and chlorine into HCl gas.

[0079] In some embodiments, the electrolytic cell includes an electrode containing Pt. In some embodiments, the electrolytic cell includes an electrode containing Ni.

[0080] In some embodiments, the electrolytic cell includes a cathode containing Pt. In some embodiments, the electrolytic cell includes a cathode containing Ni. In some embodiments, the electrolytic cell includes an anode containing Pt. In some embodiments, the electrolytic cell includes an anode containing Pt on carbon fiber. In some embodiments, the electrolytic cell includes an anode containing Pt on carbon fiber with a Pt addition amount of about 2% to about 10%, such as about 3% to about 8%, about 4% to about 6%, about 4% to about 5%.

[0081] Furthermore, bipolar membrane electrodialysis cells (e.g., electrodialysis cells described in U.S. Patent No. 9,586,181) can be used in the manner shown in Figure 1A. In this cell configuration, multiple electrodialysis units can be optionally implemented. For example, instead of having one electrodialysis unit written as [electrode|CEM|BPM|AEM|CEM|electrode] (as shown in Figure 2), [electrode|CEM|BPM|AEM|CEM|BPM|AEM|CEM|electrode], [electrode|CEM|BPM|AEM|CEM|BPM|AEM|CEM|BPM|AEM|CEM|electrode], or [electrode|CEM(|BPM|AEM|CEM) * n|electrode] can be used.

[0082] Figure 3 shows an additional method for preparing the concrete precursor disclosed herein. The method shown in Figure 3 is similar to the method shown in Figure 1A, but differs in that a CO2-rich gas, such as flue gas or air, is added to the base treatment reservoir, thereby converting Ca(OH)2 to CaCO3. This is to combine carbon recovery and sequestration with RCA upgrading. Also, because CaCO3 has low solubility in water, the separation and purification of CaCO3 from calcium-deficient liquids is much easier compared to Ca(OH)2. The same idea applies to other metal hydroxides (Mg(OH)2, Fe(OH)2, etc.) and carbonates (e.g., MgCO3, FeCO3, Fe2(CO3)3, etc., but not limited to these). CO2 recovery can be monitored in real time by detecting the CO2 concentration and flow rate at the inlet and outlet.

[0083] Figure 4 shows an additional method for preparing the concrete precursor disclosed herein. The base stream exiting the electrolytic cell is exposed to a CO2-rich gas, such as flue gas or air, on a contactor and converted to aqueous carbonates, including but not limited to Na2CO3, NaHCO3, K2CO3, and KHCO3. The aqueous base stream has a higher basicity and concentration of active substances compared to the semi-soluble base used in the method shown in Figure 3. Therefore, a faster CO2 recovery rate is expected, and CO2 can be extracted from a low-concentration stream such as air. The aqueous carbonate stream reacts with the product of the acid stream to form a carbonate precipitate, including, but not limited to, CaCO3, MgCO3, Fe2(CO3)3, or Al2(CO3)3. Since different carbonate products precipitate at different pH levels, it is possible to obtain pure products by carefully controlling the titration process.

[0084] Figure 5A shows an additional method for preparing the concrete precursor disclosed herein. In this approach, the filtrate from the acid treatment is subjected directly to electrolysis. Semi-soluble hydroxides are formed on the cathode side of the electrolytic cell and can be separated / purified for sale. Thus, fewer steps are involved, and therefore fewer reactors are required. Furthermore, only one membrane is required in the electrolytic cell, which can reduce costs. Several electrolytic cells can be used in the method shown in Figure 5A. Figure 5B shows a first design using oxidation of water at the anode and reduction of water at the cathode. The two reservoirs are separated using only AEM. Chlorides can pass from the cathode side to the anode side during electrolysis. The filtrate from the acid treatment, containing CaCl2 or other soluble salts, is sent to the cathode side, and the resulting solution contains a high hydroxide content dissolved in both water and slurry. To increase conductivity, a small amount of a salt such as 0.01M to 1M NaCl or KCl can be added to the anode side. Figure 5C shows a second design, which is the same as Figure 5B except that the design in Figure 5C uses oxygen reduction at the cathode. Figure 5D shows a third design, which is the same as Figure 5B except that the design in Figure 5D uses hydrogen oxidation at the anode.

[0085] Figure 6 shows an additional method for preparing the concrete precursor disclosed herein. This approach combines all the separate steps described in the original approach. The RCA dissolution step (acid treatment step in Figure 1A) is carried out in the anode reservoir of the electrolysis cell, and the hydroxide precipitation step is carried out on the cathode side of the cell, as shown in Figure 5A. This system requires minimal equipment and therefore has a lower capital expenditure to implement. Furthermore, the acid is consumed by Ca(OH)2 as soon as it is generated at the anode. The hydroxide generated at the cathode reacts with CaCl2 to form a precipitate. Thus, the pH gradient across the AEM is small. This is beneficial because it reduces undesirable ion leakage, reduces concentration overpotential, and leads to lower energy costs. Examples of hydroxides include, but are not limited to, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and iron hydroxide (both iron(II) and iron(III)).

[0086] While a two-chamber single AEM membrane electrolytic cell offers advantages in component cost and complexity compared to multi-membrane systems, it presents several unique challenges in scale-up. Specifically, this configuration separates products temporally rather than spatially, compared to a two-membrane three-chamber electrolytic cell. To address this peculiarity, batch systems (Figure 9) and continuous systems (Figures 7, 8, and 10) have been found to be useful. In a batch configuration (e.g., Figure 9), continuous processing would be achieved by a series of settling tank electrolytic cell pairs connected by a circulation pump. In this configuration, a given tank can be filled, allowing the solution to circulate through the electrolytic cell, enabling the desired hydroxide to precipitate from the solution and be collected in a connected setting tank (Figure 9). Continuous production can be achieved by several alternating fillings and processing of these pairs.

[0087] In a continuous system (e.g., sequential electrolysis or continuous electrodistillation by sequential base treatment, Figures 7 and 8), several pairs of combined electrolytic cell settling tanks would be arranged in series. Different voltages are applied to each electrolytic cell unit to precipitate different hydroxide species with lower power consumption. The solution being treated flows slowly from one cell to the next, thereby creating a gradient or pH (Figure 10), and the precipitated product will move down the line (Figures 7 and 8).

[0088] Some embodiments provide a mobile device for carrying out the methods described herein, for example, a device configured to be mobile and / or attached to a mechanism for moving the device from one place to another.

[0089] For example, an additional aspect of this disclosure provides a mobile treatment plant for removing contained chemicals from waste, which mobile treatment plant is A mobile electrochemical cell 100 configured to reduce the chemical content in waste, the electrochemical cell comprising an anode reservoir 101 containing an anode and an acid, and a cathode reservoir 102 containing a cathode and a base, wherein the anode reservoir and the cathode reservoir are separated by a separator 103, or A contactor 104 configured to feed waste into an electrochemical cell 100, A filtration system 105 in contact with the anode reservoir, The system includes a filtration system 106 in contact with a cathode reservoir.

[0090] In some embodiments, the mobile treatment plant consists of a rail vehicle, which is transported by rail to a location where the waste is accessible. In some embodiments, the mobile treatment plant consists of a trailer, which is transported by road to a location where the waste is accessible. In some embodiments, the mobile treatment plant consists of a truck, which travels by road to a location where the waste is accessible. In some embodiments, the mobile treatment plant consists of a barge, which is transported by water to a location where the waste is accessible. In some embodiments, the mobile treatment plant consists of a ship, which travels on water to a location where the waste is accessible. In some embodiments, the mobile treatment plant consists of an aircraft, which travels by air to a location where the waste is accessible.

[0091] Specific embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the operations described in the claims may be performed in a different order and still achieve the desired results. In one embodiment, the process depicted in the accompanying drawings does not necessarily require a specific or sequential order to achieve the desired results. In some examples, multitasking and parallel processing may be advantageous. [Examples]

[0092] Example 1. Treatment of 2 kg batch RCA with 0.5 M hydrochloric acid with gentle stirring. Hydrochloric acid is a strong acid that can be used to dissolve concrete mortar. Described herein is the dissolution of mortar from a 2 kg batch of recycled concrete aggregate (RCA) in a shaking reaction vessel using a 0.5 M hydrochloric acid solution to obtain recovered natural concrete aggregate.

[0093] procedure: 0.58 L of 37% w / w HCl was slowly added to 12.98 L of tap water. The mixture was mechanically stirred until homogeneous. 2 kg of RCA (7.5-9% w / w CaO) was added to a 6-gallon plastic drum with a sealed lid. In a fume hood, 13.7 L of 0.5 M HCl solution was slowly added to the RCA in the drum. When foaming stopped, the drum lid was sealed and the drum was placed in an orbital shaker. The slurry was shaken at 80-120 rpm for 3-48 hours. The liquid contents of the drum were decanted, and the remaining solid was washed multiple times with tap water until the solution on top of the solid was clear.

[0094] After washing the solid, it was placed on a #8 sieve and rubbed on the sieve for several minutes to remove any remaining fine powder / mortar. The aggregate was then placed in a container for a final rinse with tap water. The treated aggregate and fine powder were placed in separate containers and dried.

[0095] Example 2. Treatment of RCA with HCl in a packed bed reactor (form factor 1). This specification describes the dissolution of mortar from a 10 kg batch of RCA in a packed-bed reactor using a 0.5 M hydrochloric acid solution, with the packed bed being prepared from RCA. This describes the use of reactor form factor 1.

[0096] Using the solution preparation procedure of Example 1, 62 L of 0.5 M HCl was prepared. 10 kg of RCA (7.5-9% CaO) was added to the 10-foot reaction tube of the packed-bed reactor shown in Figures 11 and 12.

[0097] Procedure overview: 1. The pump tubing was connected and all valves were positioned correctly. 2. Enables data collection (conductivity and pH). 3. The acid treatment reaction was initiated by pumping acid into the packed bed reaction tube. 4. The process was continued for 3 to 48 hours. 5. The acid solution was drained from the packed bed reaction tube, and the RCA bed was rinsed with water. 6. The processed RCA was removed from the packed-bed reaction tube.

[0098] The following SOP was used in the procedure described above.

[0099] Section 1. Preparation of reaction materials 1. Secure the lid onto the acid tank, ensuring that the inlet and outlet unions are properly oriented toward the inlet and outlet lines. 2. Disconnect the peristaltic pump tubing from the reactor inlet port and replace it with the tubing connected to the sink. Turn the tap to fill the reservoir with water up to the water filling line marked on the side of the reservoir. Do not perform multiple tasks simultaneously during this process. Leaving the reservoir unattended may cause it to overflow. The water filling line indicates 60 gallons, which is the minimum liquid level required to ensure the reservoir pH probe is submerged when the agitation impeller is on. 3. Put on a face shield and elbow-length rubber gloves. Prepare the acid solution inside the fume hood by mixing the desired amount of concentrated HCl with water in a bucket. For 10 kg of RCA and 0.5 moles of HCl, this is 2.3 L of 37% HCl diluted in 59 L of H2O. 4. Using tubing and a peristaltic pump, transfer the concentrated acid solution from the bucket in the fume hood to a reservoir filled with water. 5. After transferring the acid, carefully bring the end of the tube in the bucket to the reservoir and submerge it in the liquid. Then, detach the tube from the peristaltic pump, hold the middle of the tube, and raise it above the height of the reservoir to drain any remaining acid into the reservoir. 6. Connect the tubing used to transfer the acid to the sink and rinse with water. Do not attempt to pull the peristaltic tubing away from the barb fitting above the sink (you may injure yourself when the peristaltic tubing is finally released). To remove it from the barb, you must cut the peristaltic tubing. 7. Cleanup: Return the concentrated HCl acid to the acid cabinet. Fill the acid solution bucket with water and rinse. Pour the first rinse solution into the acid waste container. Subsequent rinse solutions may be poured into the sink. 8. Measure out the desired amount of RCA using a tare-weighted bucket. When transferring the RCA to the bucket, ensure that a dust collector is nearby to handle any dust. Then, to suppress dust, moisten the RCA with a small amount of water before filling the reactor. Set aside for filling the tubes.

[0100] Section 2: Filling the reactor for the experiment 1. Press the E-stop button before opening the reactor door. 2. Close the electronic ball valve at the reactor outlet, and then disconnect the outlet line with a quick-disconnect union. Closing the valve prevents any remaining liquid in the line from leaking out when the line is disconnected. 3. Use a ladder to close the ball valve at the reactor inlet, then disconnect the inlet line with a quick-disconnect union. 4. Use a quick disconnect union to detach the overflow line at the top of the reactor, and this line should be emptied. 5. Pull the tubular reactor out of the enclosure by pressing the yellow release lever. 6. Unscrew the reactor lid from the top of the tube and set it aside. 7. Using a plastic spoon, add one spoonful of unreacted RCA at a time. For a well-filled floor, one person should tap the sides of the reactor wall with two heavy tools while the other scoops the RCA onto the top. Tapping reduces the porosity of the floor to 40%. Scooping the RCA without tapping will result in an initial porosity of 50% for the floor. A lower porosity of the floor reduces channeling, while a higher porosity of the floor exposes more RCA surface for the reaction. 8. Ensure the quick disconnect union is facing the tube, then twist the lid back onto the tubular reactor. 9. Press down the yellow release lever and slide the tube back into the enclosure until it locks into place. 10. Reconnect the pipe inlet line and overflow line to the quick-disconnect unions on the top and side of the pipe cap, respectively. Open the manual ball valve on the pipe inlet line. 11. Reconnect the pipe outlet to the quick-disconnect union at the top of the reservoir. Set the outlet electronic ball valve to 50% open. 12. Lower the conductivity probe into the sampling port on the reservoir cover and ensure all cables are plugged into the meter so that data can be collected.

[0101] Section 3. Initiation of the reaction 1. Verify that the peristaltic pump speed is set to the desired output setting value. 2. Set the agitator motor to a reasonable speed so that the acid reservoir is thoroughly mixed without splashing the liquid or damaging the impeller. 3. Distribute the leak detection sensors evenly across the entire bottom of the enclosure. 4. Log in to the automated code and start collecting conductivity data. 5. Close the enclosure door, release the E-stop, and start the acid flow. Verify that the leak detection sensors are lit with green LED lights, indicating that they are working. If tripped by acid or other liquid, the lights will turn red and the pump will lose power. 6. Follow the calibration procedure for the liquid level sensor and start automatic ball valve control to maintain the liquid level.

[0102] Section 4. Monitoring the reaction 1. Monitor the reaction using a WYZE camera, or observe the reaction yourself. 2. Download data across the entire reactor or at the end of the reaction. 3. A sudden cessation of the acid flow or a drop in the liquid level indicates that a leak has been detected and power to the pump has been cut off.

[0103] Section 5. Stopping the reaction 1. Press the emergency stop button. 2. Open the electronic ball valve to drain the fluid from the pipe. 3. Open the door and stop the agitator motor. 4. Close the ball valve completely, then disconnect the outlet line from the reservoir. 5. Close the inlet line ball valve and disconnect the inlet line and overflow line from the top of the tubular reactor. 6. Remove the reactor from the enclosure and place a bucket under the sand trap. 7. Wearing full PPE and a face shield, slowly open the ball valve at the bottom of the sand trap to empty any collected sand and acid that cannot be discharged through the tube by any other means. If sand is clogging this outlet, slide a small section of peristaltic pump tubing into the ball valve to release the blockage. Be careful not to let sand and acid splash when it is released. Pour any excess acid into the reservoir, leaving only the sand in the bucket. 8. Next, open the RCA port on the side of the tubular reactor and discharge the RCA into the same bucket containing the sand. Rinse the RCA / sand with water, discarding the rinse water into the waste container for the first two rinses, and then into the sink. 9. Store the acid in a reservoir until it can be processed by a base reaction.

[0104] Section 6. Cleaning the reactor 1. Thoroughly clean the threads of the RCA port on the side of the reactor to remove all sand. Apply Teflon tape to the threads before screwing the plug back into the port. Tighten the plug and ensure there are no leaks. 2. Slide the tube back into the enclosure and reconnect the tube's inlet and overflow lines to the quick-disconnect unions on the top and side of the tube's cap, respectively. Open the manual ball valve on the tube's inlet line. 3. Reconnect the pipe outlet to the quick-disconnect union at the top of the reservoir. Set the outlet electronic ball valve to 50% open. 4. Fill the reservoir with water as described in step 2 of section 1. 5. Close the enclosure door and start the peristaltic pump to recirculate water from the reservoir through the tubing and reaction tubes until the acid and fine particles are removed and collected in the reservoir. 6. After rinsing, the water should be pumped directly from the reservoir to the waste drum. 7. The reactor is now ready to be filled with fresh RCA and acid. When the tubes are removed from the enclosure and filled with the next batch of RCA, place a bucket under the tubes and open the sand trap ball valve to drain the rinse water trapped under the tubes and discard it into the waste drum.

[0105] result: Visual inspection (Figure 12B) showed that the RCA had a high mortar content when form factor 1 was used as described herein.

[0106] Example 3. Acid treatment of RCA cables in a rotating drum (form factor 2) As is evident from Example 2, even when using a stoichiometric amount of HCl, dilute HCl (less than 1 mole) alone was insufficient to remove all the mortar from the RCA. Therefore, mechanical wear of the RCA during treatment, such as tumbling, was investigated as a means to increase mortar removal. This specification describes a procedure for inducing mechanical wear in a rotating drum reactor to enhance the effectiveness of the reaction. This protocol describes the use of a form factor 2 acid reactor.

[0107] procedure: 0.58 L of 37% w / w HCl was slowly added to 12.98 L of tap water. The mixture was mechanically stirred until homogeneous. 2 kg of RCA (7.5-9% w / w CaO) was added to a 6-gallon plastic drum fitted with a lid with an O-ring. In a fume hood, 13.7 L of 0.5 M HCl solution was slowly added to the RCA in the drum. When foaming stopped, the drum lid was sealed and the drum was placed on a rotary mixer located in a well-ventilated area. The rotary mixer was rotated at 60 rpm with the sealed drum. Continuous pH recording was possible with an in situ pH probe. After reacting for 1-48 hours, the mixer was rotated. As shown in Figure 13, the pH of the reaction increased over time, reaching a steady state of approximately pH 1.3 after about 10 hours of reaction.

[0108] After the target reaction time was complete, the liquid contents of the drum were decanted, and the remaining solid was washed multiple times with tap water until the solution on top of the solid was clear. After washing the solid, it was placed on a #8 sieve and rubbed on the sieve for several minutes to remove any remaining fine powder / mortar. The aggregate was then placed in a container for a final rinse with tap water. The treated aggregate and fine powder were placed in separate containers and dried.

[0109] Results: Visual inspection showed that the treated RCA contained significantly less mortar than was observed for the filler bed reaction at the same reaction time.

[0110] Example 4. Acid treatment of RCA in a rotating drum (form factor 2) with continuous HCl treatment. As is evident from Example 3, mechanical wear of the RCA during acid treatment, such as tumbling, enhanced the effectiveness of the reaction. However, using a dilute HCl solution requires a large amount of acid solution, which reduces the loading capacity for the RCA and increases capital expenditure (CapEx). For example, treating 10 kg of RCA with 0.5 M HCl requires more than 60 L of acid, exceeding the capacity of a 22.7 L (6 gallon) bucket. By dividing the acid into six 10 L portions and reacting each portion with the RCA sequentially, the same bucket can accommodate 10 kg of RCA. This approach allows for the treatment of significantly larger quantities of RCA within a reactor of limited size.

[0111] This specification describes the treatment of a 5 kg batch of RCA by three consecutive treatment runs using 10 L of fresh 0.5 M HCl for a total of approximately 30 L of 0.5 M HCl treatment. For each batch, the RCA was reacted with the HCl solution at a rotation of 60 rpm for 6 hours, and the pH was continuously monitored. This protocol describes the use of a form factor 2 acid reactor in multi-batch mode.

[0112] procedure: A 10 L 0.5 M HCl solution was prepared as described in Example 3. 5 kg of RCA (7.5-9% w / w CaO) was added to a 6-gallon plastic drum fitted with a lid having an O-ring. In a fume hood, the 10 L 0.5 M HCl solution was slowly added to the RCA in the drum. When foaming stopped, the drum lid was sealed and the drum was placed on a rotary mixer located in a well-ventilated area. The rotary mixer rotated the sealed drum at 60 rpm. Continuous pH recording was possible with an in situ pH probe. The mixer was rotated at 60 rpm for 6 hours. The drum was opened, the liquid contents of the drum were decanted, and 10 L of fresh 0.5 M HCl (see above) was added. The drum lid was sealed and the mixer was rotated at 60 rpm for another 6 hours. The drum was opened, the liquid contents of the drum were decanted, and 10 L of fresh 0.5 M HCl (see above) was added. The drum lid was sealed and it was rotated for another 6 hours at 60 rpm. The total acid treatment time for a 5 kg batch of RCA was 18 hours.

[0113] At the end of the third experiment, the liquid contents of the drum were decanted, and the remaining solid was washed multiple times with tap water until the solution on top of the solid was clear. After washing the solid, it was placed on a #8 sieve and rubbed on the sieve for several minutes to remove any remaining fine powder / mortar. The aggregate was then placed in a container for a final rinse with tap water. The treated aggregate and fine powder were placed in separate containers and allowed to dry.

[0114] result: Visual inspections after each run (Figures 14A, 14B, and 14C) showed a decrease in the mortar content of the treated RCA. The time course of pH for each run (Figure 15) showed that the base content of the mortar significantly neutralized the acid during the first acid treatment, but the neutralization effect decreased with subsequent treatments. The pH and conductivity for each run are summarized in Table 1 below.

[0115] [Table 1]

[0116] Example 5. Measurement of water absorption rate of aggregate Aggregate water absorption is an important test in the concrete industry. Low water absorption in aggregate correlates with high concrete strength. This specification describes a procedure for determining the water absorption of recycled coarse aggregate.

[0117] procedure: Acid-treated RCA and untreated (control) RCA (approximately 500g of RCA per sample, 3 samples per group) were rinsed with tap water for 2 minutes while gently agitating the filter basket. After draining, each sample was placed in an aluminum tray and placed in a 230°C oven for 24 hours. The sample trays were removed, cooled for approximately 10 minutes, and then weighed (along with the samples). The dry weight of the RCA was obtained by subtracting the tray mass (Note: The tray is weighed after the total weight to remove the tray weight and any residue adhering to it).

[0118] After determining the dry weight of each sample, each sample was placed in a container. Each container containing the sample was filled with water at least three times the volume of the RCA and immersed for 24–72 hours (the treatment time was recorded). After 72 hours, the water was drained from each container. Each sample was placed on a sheet of paper towels. The rocks were dried by gently rubbing them with additional paper towels. Each sample was then dried for several minutes until there was no visible water (gloss) on the surface. The mass of each sample was then recorded.

[0119] The water absorption rate (wa) as a percentage was calculated as follows: wa %=[(sw-dw) / dw]x100 In the formula, sw is the saturated weight and dw is the dry weight. The improvement in acid treatment was tested using a control.

[0120] result: Several RCA treatment groups were analyzed using the method described herein. Figure 16 shows the results for untreated RCA and RCA treated with various acids. Figure 17 shows the water absorption levels of unused aggregate, untreated RCA, and RCA treated with HCl, which are lower than the industry requirements for cement aggregate. Figure 18 shows the water absorption rates of untreated and treated RCA using form factors 1-3 with three multi-batch processing arms (3-batch and 6-batch rotary drums).

[0121] Example 6. Form Factor 3 of an Acid Reactor The use of form factor 2, as described in Examples 3-4, presents several design challenges: 1) low volume occupancy due to RCA, 2) numerous reactor units for scaling, 3) relatively high CapEx, and 4) relatively high operating costs (OpEx) due to the moving liquid. A new design was needed to reduce the liquid / solid volume or mass ratio of the drum while maintaining the HCl / RCA stoichiometry.

[0122] This specification describes a drum reactor design for treating RCA with acid, addressing the problems of form factor 2. This design provides a lower liquid / solid volume ratio, and as a result, more energy is dedicated to the mechanical wear of the RCA, e.g., tumbling, than simply moving the liquid. This design, form factor 3, maintains the HCl / RCA stoichiometry. Form factor 3 (Figure 18) includes a rotating drum reactor with inlet and outlet ports that allow for continuous circulation of the HCl solution within the reactor at a level just sufficient to treat the RCA, while minimizing the volume of the solution.

[0123] Example 7. Base reaction and filtration procedure As described herein and in the claims, a liquid rich in one or more metal ions may be brought into contact with a base to produce a precipitate containing one or more metal ions and a liquid deficient in one or more metal ions. Embodiments relating to the treatment of RCA with an acid produce a liquid rich in calcium ions (e.g., one or more of CaCl2, CaSO4, and Ca(NO3)2). When a base, such as NaOH, is brought into contact with a liquid rich in calcium ions, Ca(OH)2 (and / or other metal hydroxides such as Mg(OH)2, Fe(OH)2) may be formed.

[0124] This specification describes the procedure for the base reaction. NaOH was added to the reacted acid (e.g., an acid solution previously used to treat RCA) to precipitate Ca(OH)2 and other metal hydroxides and / or carbonates. The precipitate was then separated from the liquid phase by vacuum filtration. Subsequently, the precipitate was washed with water after the filtration step to remove salt contaminants.

[0125] Base reaction procedure: The reacted acid solution / sludge from the treatment of RCA with HCl solution (e.g., from Examples 1-4) was added to a 22-gallon base reactor. The mixture was blended for 2 minutes using a cement mixer, and then the pH and conductivity were recorded. A tank of appropriate size was placed in a fume hood, and then the amount of NaOH required to achieve the desired molar concentration, e.g., 1-5 M, was added. The base solution was mixed until thoroughly blended, and then the initial pH and conductivity of the base solution were recorded. Using a peristaltic pump and tubing, all of the base solution was transferred through a port on the lid of the base reactor while mixing the base reactants for 10-30 minutes. The pH and conductivity of the precipitate slurry were then recorded. A lab-top version of the base titration is shown in Figure 20, which shows that the precipitate increases with pH.

[0126] Filtration procedure: A Buchner funnel of appropriate size was prepared, containing a filter cloth and filter paper on top of the cloth. A vacuum tube was connected to a small vacuum pump to an 11 L filtrate collector (suction canister), and the outlet of the Buchner funnel was connected to the filtrate collector using the vacuum tube. The filter paper was wet with water and then flattened to remove air bubbles from the cloth. The Buchner funnel was fitted with a lid, and the vacuum pump was activated to form a good seal with the filter paper. After preparing the Buchner funnel, the vacuum pump was stopped, the lid was removed from the funnel, and the precipitate slurry was added. The base precipitate slurry was slowly poured into the Buchner funnel. The lid was replaced on the Buchner funnel, and the vacuum pump was activated to begin removing the filtrate from the precipitate. In parallel with the filtration, 30 L of fresh water was preheated to 80°C in a cement mixer using a vacuum cooker for washing. The filtration process continued until no more water was removed from the filtered cake, and the viscosity of the precipitate appeared to be that of a conditioner. The lid was periodically removed during filtration to check the water content in the filtered cake. If cracks formed in the cake, the cake was compressed using a spoon to fill the cracks, thereby improving the efficiency of filtration. The pH and conductivity of the filtrate were recorded. The filtered cake was washed with preheated water until the conductivity of the collected rinse water was less than 20 mS / cm.

[0127] Post-processing steps: Stainless steel baking sheets with silicone covers (and perforated plastic lids where applicable) were weighed, and the wet precipitate was then added to the baking sheets, and the weight of each loaded sheet was measured. The precipitate was dried in a thermotron at >120°C for at least 48 hours, or until the weight no longer decreased over time. It was observed that the drying process occurred much faster without a lid. A tray containing cement precursor obtained by treating 5 kg of RCA with acid and then with NaOH is shown in Figure 21 before and after drying. Finally, the weight of the dried precipitate on the baking sheets was measured, and the dried precipitate was then transferred to a pulverizer and pulverized for 2 minutes to form a powder. Ball milling was performed optionally.

[0128] Example 8. Preparation and compression test of cement cylinder As described herein and in the claims, the cement precursor obtained by the acid treatment and subsequent base titration described in Example 7 may be used to prepare cement and cement materials, such as concrete.

[0129] This specification describes the procedure for preparing a cement mortar test cylinder. This is based on ASTM C129, but with significant modifications to reduce the size of the test specimen from a 2×2×2 inch cube to a cylinder measuring 0.9 cm in diameter × 2 cm.

[0130] Materials and equipment A sieving machine (model TS-4), a compressor (AC-325), concrete cylinder molds, and a slump test set were obtained from Gilson (Lewis Center, OH). A vibration table was obtained from vibropro. A 5.0 cubic foot portable concrete mixer was obtained from Ryobi.

[0131] Cement mortar mix (7-8 cylinders for each mix): 1. Mix 1: Standard Type I Cement a. New sand: 10 cy * 4g / cy / 4.5 * 3 = 26.67g b. New cement (Type I): 10cy * 4g / cy / 4.5 = 8.88g c.Wed: 10cy * 4g / cy / 4.5 * 0.5 = 4.44g 2. Mixture 2: Standard Type II / V Cement a. New sand: 10 cy * 4g / cy / 4.5 * 3 = 26.67g b. New cement (Type I): 10cy * 4g / cy / 4.5 = 8.88g c.Wed: 10cy * 4g / cy / 4.5 *0.5 = 4.44g 3. Cement containing 3:30% HL RCA cement a. Sand: 10cy * 4g / cy / 4.5 * 3 = 26.67g b. Recycled cement: 10cy * 4g / cy / 4.5 * 0.3 = 2.67g c. New cement (Type I): 10cy * 4g / cy / 4.5 * 0.7 = 6.2 d.Wed: 10cy * 4g / cy / 4.5 * 0.5 = 4.44g

[0132] Casting mortar cylinder: One hour before casting, a release agent was sprayed onto the cylinder mold. Using a paint stick, dry sand and cement were mixed in a 16-ounce mixing jar according to the above formulation, and water was added to the mixture using a micropipette. The slurry was mixed for 45 seconds using a paint stick on a working vibrating table (150 Hz). The mixing jar was removed from the vibrating table, and the mold was placed on the vibrating table. While vibrating the mold, the wet mixture was scooped into the mold and distributed into the eight cylinder holes using a spatula. One and a half minutes after pouring the first scoop, all holes were filled with screws. Then, using a spatula, any overflowing mixture was moved into the holes. Vibration was continued for 3 minutes. After casting all the cylinders, the vibrating table was stopped. Next, a sheet of towel was moistened and wrapped around a set of molds (7-8 cylinders). The wrapped molds were then placed in Ziploc bags and cured under these conditions for 3 days. Each cylinder was removed from the mold on the 3rd day and wrapped in another wet towel. Next, each cylinder was placed in a Ziploc bag and allowed to harden until it was crushed. Crushing was performed on the 7th or 10th day.

[0133] Additional test cylinders were prepared according to the formulations provided in Table 2. Cylinder compression tests were performed according to ASTM C39. Slump tests were performed according to ASTM C143.

[0134] [Table 2]

[0135] Example 9. Evaluation of the cement precursor recycling process Figure 22 outlines the combinations of acid treatment, base reaction, filtration, drying, calcination, and blending to obtain cement precursors suitable for final cement. This specification describes the evaluation of this recycling process and the performance of recycled concrete aggregates. Specifically, a comparison of the mineralogical and performance characteristics between new Portland cement and cement prepared from recovered solids obtained through the processes disclosed herein is presented.

[0136] X-ray fluorescence (XRF) analysis of the recovered solid revealed different ratios of specific minerals compared to new cement. The recovered RCA cement had high Cl and Na content but was deficient in CaO and SiO2 (Table 3).

[0137] [Table 3]

[0138] These results indicated that the recovered solid needed to be augmented to bring its chemical composition closer to that of new cement. Therefore, CaO and SiO2 were blended with the recovered solid to obtain the compositions shown in Table 3, in the mineral ratios shown in Table 4. The approximate ratio of the treatment was 10 g of recovered solid + 4.8 g of CO + 1 g of SiO2.

[0139] [Table 4]

[0140] Using Borg's formula, we calculate the approximate proportions of the following four major minerals in cement clinker. 1. Tricalcium silicate (C3S)-alite 2. Dicalcium silicate (C2S)-B-Lite 3. Tricalcium aluminate (C3A) aluminate phase 4. Tetracalcium aluminoferrite (C4AF)-ferrite phase

[0141] Table 5 shows the values ​​of the Borg formula before and after the addition of CaO and SiO2, followed by heating to 1450°C, as described below.

[0142] [Table 5]

[0143] The improved recovered solids were blended as described above and heated to 1450°C over 60 minutes according to Table 6. The appearance before and during heating is shown in Figure 23.

[0144] [Table 6]

[0145] After calcination, the original RCA recovered solid was observed not to appear clinked / sintered. It also had a faint chlorine odor. Approximately 4% gypsum was then added to the calcined recovered cement precursor to obtain a composition suitable for cement preparation. XRF analysis of the final composition is shown in Table 7. Overall, the improved RCA cement had a good CaO / SiO2 ratio, relatively high MgO and Ca2Al2O5 content, and relatively low SO3 content.

[0146] [Table 7]

[0147] Next, the properties of the RCA cement were evaluated. Cement cylinders were prepared using the protocol and procedure disclosed in Example 8. Compression tests of these cylinders (Figure 24) showed that the RCA cement prepared from 30% recycled mixture and 70% type I cement was weaker than type I and type II / V cements. Interestingly, however, the RCA cement prepared from 30% recycled mixture and 70% type I cement appeared to be hydrophobic.

[0148] For comparison, dry type I Portland cement was treated with HCl solution as described in Examples 1-4, and then the calcium salt-rich solution from the dissolved cement was treated with NaOH solution as described in Example 7 to obtain the recovered solid.

[0149] As shown in Figure 25, batches of recovered cement precursors, starting from fresh, unreacted cement as the starting material and possessing good mineralogical replication, exhibited better performance. Adding 4% gypsum to the calcined blend significantly improved the cement's strength (Figure 26).

[0150] To further evaluate the cement precursor recycling process described herein, test cylinders were prepared using treated and untreated RCA. Recycled concrete aggregate performed significantly better than untreated RCA (Figure 27).

[0151] Example 9. H-cell electrolysis procedure As described herein and in the claims, acids and bases can be regenerated by bringing a liquid lacking one or more metal ions into contact with an electrolytic cell.

[0152] This specification describes testing an H-cell containing Ca(NO3)2 for the formation of acids and bases.

[0153] Materials and equipment The electrolytic cell was a 50 mL H-Type Electrochemical Cell Sealed obtained from DEK Research (Kowloon, Hong Kong). The carbon cathode concentration was 3 mg / cm³. 2 The electrode used was a 40% Platinum on Vulcan - Carbon Cloth Electrode (W1S1010), purchased from Fuelcell store (Boulder, Colorado). The anode was a 99.99% platinum plate electrode (10mm x 10mm x 0.1mm) coated with a PTFE-insoluble anode. The film was umasep FAA-3-PK-75, also obtained from Fuelcell store (Boulder, Colorado). The power supply was a BioLogic Potentiostat VSP-3e, manufactured by BioLogic (France). Ca(NO3)2 was obtained from Sigma-Aldrich.

[0154] procedure: 1. Cell Assembly: The anion exchange membrane was placed between two O-rings. Then, the two cell bodies were connected to the O-rings. The cell bodies were clamped to secure the membrane position. 1 cm 2 A carbon paper or cloth electrode was attached to the electrode holder and then secured to the lid of the anode chamber. 2 A carbon paper or platinum plate was attached to the electrode holder and then secured to the lid of the cathode chamber. The respective lids were then placed over both chambers. 2. 100 mL of 0.2 M Ca(NO3)2 solution was prepared by dissolving 3.28 g of Ca(NO3)2 powder in 100 mL of DI water. 40 mL of each solution was added to each electrode reservoir. 3. The anode extension cord extending from the potentiostat was attached to the anode, and the same was done for the cathode extension cord and the cathode. 4. Chronopotentiometry experiments were performed by selecting a current (10mA or 5mA). 5. pH changes were measured using a pH probe. The pH of the anode reservoir was expected to decrease due to acid (HNO3) formation. The pH of the cathode reservoir was expected to increase due to base formation (Ca(OH)2). 6. Observe the precipitate that will form as Ca(OH)2 on the surface of the cathode.

[0155] result: 1cm 2 1cm doped with Pt 2 An anion exchange membrane FAA-3-PK-74 with a carbon cloth electrode, and using voltages of approximately 10V at 50mA and approximately 5V at 10mA, the cathode reservoir was observed to turn purple due to base formation, and the anode reservoir was observed to turn clear (pH=2) after 60 minutes (Figure 28). A Ca(OH)2 shell was observed at the cathode (Figures 30A, 30B), which was consistent with the voltage increase observed at the carbon electrode and caused fouling and malfunction (Figure 29). The Pt electrode remained at a constant voltage despite having a Ca(OH)2 shell.

[0156] Example 10. Hydrogen looping for NaOH and HCl generation The hydrogen looping method is used to reduce the energy consumption of NaOH production. Since hydrogen gas is consumed at the anode and simultaneously produced at the cathode, the thermodynamic cost of HCl and NaOH production in this cell is zero. All costs are incurred due to overpotential.

[0157] Equipment and materials: CO2 electrolytic cell, 5 cm² active area (Fuelcell store (Boulder, Colorado)). Cathode end plate material was SS304L. Cathode material was pure Ni, 40 mesh (fuel cell material) obtained from McMaster-Carr. Anode end plate material: custom machined graphite. Anode material: 4 mg / cm² on carbon cloth W1S1011. 2The Pt black material was obtained from Fuelcell store (Boulder, Colorado). The membrane was an AEM (FAB-PK-130) obtained from Fuelcell store (Boulder, Colorado). The power supply was a BioLogic Potentiostat VSP-3e Potentiostat from BioLogic (France). ACS grade NaCl was obtained from Sigma-Aldrich. The peristaltic pump was a Kamoer DIPump 550 (Kamoer (Shanghai, China)). The hydrogen was 99.999%, and the UHP was obtained from Instrument depot (Rochester, NY). The mass flow controller was obtained from Alicat (Tucson, AZ).

[0158] procedure: 1. Electrolyte preparation: Use 100 mL of 1 M NaCl solution as the cathode solution. Simultaneously, use 100 mL of 1 M NaCl solution as the anode solution. 2. Cell Assembly: The cell components were assembled according to the manufacturer's instructions, which included applying a 30-pound-inch torque to secure the components. 3. Electrode connection: The cathode of the cell was connected to the working electrode cable, and the anode was connected to the counter electrode cable of the BioLogic potentiostat or Labjack. 4. Hydrogen Gas Setup: Using PTFE tubing and a mass flow controller, the hydrogen gas supply was connected to the designated inlet port of the cell. The gas outlet and electrolyte outlet were both connected to the anode reservoir, as liquid would exit from both tubing. The hydrogen flow rate was set to 20 mL / min using the mass flow controller. 5. Cell setup: The cell was placed in a water bath (88°C) preheated to the specified safe level, and then the tubing to the cell reservoir and the peristaltic pump were connected. 6. Electrolyte circulation: Both the cathode solution and anode solution were pumped using a 100 rpm peristaltic pump. 7. Electrochemical measurements: The baseline potential was established by equipping the system with the open-circuit voltage (OCV) for 1 minute. Note: A BioLogic potentiostat was used, but a Labjack+ power supply was used when high current density was required. 8. Chronopotentiometry Experiment: Various current densities were selected by setting the current using CP on Biologic or via Labjack. The desired current was applied for a predetermined time (e.g., 10-30 minutes), during which time the cell voltage was continuously recorded. 9. Determination of the concentration of NaOH: This was achieved as described in Example 11.

[0159] result: Hydrogen flows exceeding 20 mL / min had minimal effect (Figure 31), but there was some evidence of hydrogen depolarization at higher voltages (Figure 32). The Pt-carbon anode was stable up to 1.6 V under continuous voltage, and its stability was not limited by the film or Ni cathode (Figure 33). The Pt-on-Ti mesh did not show sufficient activity. The current of the Pt-Ti mesh was one-tenth that of the Pt-carbon cloth (Figure 34). While we do not wish to be bound by theory, this could be due to either (1) a lack of catalytic activity in the low-defect Pt coating, or (2) insufficient mixing of H2 and the electrolyte without a gas diffusion layer. 4 mg / cm² on carbon cloth 2 For anodes containing Pt Black, a continuous decrease in current was observed, and instability was shown even at 1.4 volts (Figure 35). Pt level on carbon cloth was 2 mg / cm³. 2 By reducing the Pt black content and decreasing the current, a more stable configuration was obtained (Figure 36), but these results also indicate that the amount of Pt added has a significant effect on the hydrogen oxidation reaction rate.

[0160] Example 11. Chloride-alkaline electrolysis and automatic titration apparatus procedure A chlorine-alkali cell was operated in the laboratory to obtain the baseline energy cost (kJ / mol) for base (NaOH) generation. The energy cost (kJ) was measured using a power supply connected to a potentiostat or lab jack. The amount of sodium hydroxide generated was determined by a custom-made automated titrator.

[0161] Equipment and materials: CO2 electrolyzer, 5cm 2 The active area (Fuelcell store (Boulder, Colorado)). The cathode end plate material was SS304L. The cathode material was pure Ni, 40 mesh (fuel cell material) obtained from McMaster-Carr. Anode end plate material: titanium machined in-house. The anode was a dimensionally stable anode (DSA) obtained from TIBROMTACK. The membrane was GI-N417 (PTFE fiber reinforced perfluorosulfonic acid (PFSA)) obtained from Fuelcell store (Boulder, Colorado). The power supply consisted of a BioLogic Potentiostat VSP-3e Potentiostat (Biologic, France) or a Labjack T4 (LabJack (Lakewood, CO)) and a Hyelec 30V 10A Adjustable Switching Regulated DC Bench Power Supply. ACS grade NaOH and NaCl, as well as 1M HCl standard solution, were obtained from Sigma-Aldrich. pH probes were obtained from Teyleten. Wireless connectivity was via an Arduino UNO WiFi REV2. The syringe pump was a KDS Legato™ 270 (Sigma-Aldrich). The stirring plate was a Hot Plate Stirrer, Multi-Position (8-Position) | BT Lab Systems (Saint Louis, MO).

[0162] procedure: 150 mL of 1 M NaOH solution was prepared as the cathode solution, and 150 mL of 5 M NaCl solution was prepared as the anode solution. The electrolytic cell was assembled according to the manufacturer's instructions. The torque applied to join the units was 30 lb-inches. The cathode of the cell was connected to the working electrode cable, and the anode was connected to the counter electrode cable of the BioLogic potentiostat or Labjack. 1. Cell setup: The cell was placed in a water bath (88°C) preheated to the specified safe level, and then the tubing to the cell compartment and the peristaltic pump were connected. 2. Electrolyte circulation: The peristaltic pump was started at 100 rpm, and both the cathode liquid and anode liquid were pumped to their respective reservoirs. 3. Electrochemical measurements: The baseline potential was established by equipping the system with the open-circuit voltage (OCV) for 1 minute. Note: A BioLogic potentiostat was used, but a Labjack+ power supply was used when high current density was required. 4. Chronopotentiometry Experiments: Experiments were conducted at various current densities by selecting a CP on Biologic or setting the current via Labjack and applying the desired current over a predetermined period (e.g., 10-30 minutes) while continuously recording the cell voltage. 5. Sample Collection and Automated Titration: After each chronopotentiometry experiment, two 10 mL aliquots of the NaOH-containing cathode solution were collected using a syringe. Each sample was then transferred to a beaker containing a magnetic stirring rod and a pre-positioned pH probe. The two beakers containing the NaOH aliquots were stirred on a multi-channel stirring plate. Two 30 mL syringes were filled with 30 mL of 1 M HCl standard, and these syringes were loaded into a syringe pump, with the plastic syringe tips submerged in the titrant to ensure efficient titration. An automated titration program was configured and executed. The endpoint was ensured to exceed the equivalence point of the NaOH-HCl titration by having more than a stoichiometric amount of HCl. The titration was monitored, and data (volume of titrant required to achieve neutrality) was obtained.

[0163] result: 200mA / cm 2 The repeated runs over several days demonstrated good stability and reproducibility (Table 8). The energy cost for generating NaOH under various currents ranged from a low of 2.10 ± 0.01 to a high of 4.02 ± 0.03 kWh / kg. These energy costs exceeded those of industrial electrolytic cells (Figure 37). One reason for this was that sweeping to high current densities led to cell instability (see Figure 38). While not theoretically bound, cell instability may be due to oxidation of the carbon paper at higher potentials.

[0164] [Table 8]

[0165] A comparison of the hydrogen looping method (Example 10) with the chloro-alkali method shows that hydrogen looping achieves better efficiency (Figures 39A, 39B, and 39C). Hydrogen looping is likely to achieve a NaOH output of 1 kWh / kg, although the current density remains uncertain.

Claims

1. A method for preparing a concrete precursor, (a) A step of bringing inorganic solid waste containing one or more metal ions into contact with an acid to produce the concrete precursor and a liquid rich in the one or more metal ions, (b) A step of contacting the liquid rich in one or more metal ions with a base to produce a precipitate containing one or more metal ions and a liquid lacking one or more metal ions, (c) A step of bringing the liquid lacking one or more metal ions into contact with an electrolytic cell to regenerate the acid and the base, (d) A step of repeating each of steps (a) to (b) at least once using the acid and base from step (c), Methods that include...

2. The method according to claim 1, wherein the inorganic solid waste includes one or more of the following: recycled concrete aggregate (RCA), smelting slag, blast furnace slag, incinerator bottom ash, and electronic equipment waste.

3. A method for preparing a concrete precursor, (a) A step of bringing recycled concrete aggregate (RCA) containing one or more metal ions into contact with an acid to produce the concrete precursor and a liquid rich in the one or more metal ions, (b) A step of contacting the liquid rich in one or more metal ions with a base to produce a precipitate containing one or more metal ions and a liquid lacking one or more metal ions, (c) A step of bringing the liquid lacking one or more metal ions into contact with an electrolytic cell to regenerate the acid and the base, (d) A step of repeating each of steps (a) to (b) at least once using the acid and base from step (c), Methods that include...

4. The method according to any one of claims 1 to 3, wherein the electrolytic cell is a single-membrane electrolytic cell, a two-membrane salt decomposition electrolytic cell, a multi-membrane salt decomposition electrolytic cell, a chlorine-alkali electrolytic cell, a bipolar membrane electrodialysis electrolytic cell, or any combination thereof.

5. A method for preparing a concrete precursor, (a) A step of bringing recycled concrete aggregate (RCA) containing one or more metal ions into contact with an acid to produce the concrete precursor and a liquid rich in the one or more metal ions, (b) A step of contacting the liquid rich in one or more metal ions with a base and carbon dioxide to produce one or more metal carbonates derived from the one or more metal ions and a liquid lacking the one or more metal ions, (c) A step of bringing the liquid lacking one or more metal ions into contact with an electrolytic cell to regenerate the acid and the base, Methods that include...

6. The method according to any one of claims 1 to 5, wherein step (b) includes sequentially contacting the liquid rich in one or more metal ions with two or more independently selected bases.

7. The method according to any one of claims 1 to 6, further comprising the step of separating the precipitate from step (b) and the liquid lacking the one or more metal ions before step (c).

8. A method for preparing a concrete precursor, (a) A step of bringing recycled concrete aggregate (RCA) containing one or more metal ions into contact with an acid to produce the concrete precursor and a liquid rich in the one or more metal ions, (b) A step of contacting the liquid rich in one or more metal ions with a base containing carbonates and / or bicarbonates to produce one or more metal carbonates derived from the one or more metal ions and a liquid lacking the one or more metal ions, (c) A step of bringing the liquid lacking one or more metal ions into contact with an electrolytic cell to regenerate the acid and the base, Includes, A method wherein the carbonate and / or bicarbonate is produced by mixing carbon dioxide and a metal hydroxide.

9. The method according to any one of claims 5 to 8, wherein the carbon dioxide is provided as a composition, and the composition comprises carbon dioxide and at least one additional gas.

10. The method according to claim 9, wherein the composition contains carbon dioxide in an amount of about 0.01% to about 99.9% by weight, or about 0.01% to about 1.5% by weight, or about 1% to about 10% by weight, or about 50% to about 90% by weight.

11. The method according to any one of claims 5 to 8, further comprising the step of repeating each of steps (a) to (b) at least once using the acid and base from step (c).

12. The method according to any one of claims 8 to 11, wherein the carbonate and / or the bicarbonate is selected from sodium, potassium, lithium, and any combination thereof.

13. A method for preparing a concrete precursor, (a) A step of bringing recycled concrete aggregate (RCA) containing one or more metal ions into contact with an acid to produce the concrete precursor and a liquid rich in the one or more metal ions, (b) A step of bringing the liquid rich in one or more metal ions into contact with an electrolytic cell to regenerate the acid and generate a precipitate containing one or more metal ions, Methods that include...

14. The method according to claim 13, further comprising the step of separating the concrete precursor from the liquid rich in one or more metal ions in step (a) before step (b).

15. The method according to claim 13 or 14, further comprising the step of separating the precipitate from the acid in step (b).

16. The method according to any one of claims 13 to 15, further comprising the step of repeating step (a) at least once using the acid from step (b).

17. The method according to any one of claims 13 to 16, further comprising the step of separating the precipitate from the liquid lacking the one or more metal ions in step (b).

18. The method according to any one of claims 13 to 17, wherein the sequential electrolysis is carried out via continuous electrodistillation.

19. A method for preparing a concrete precursor, (a) A step of bringing recycled concrete aggregate (RCA) containing one or more metal ions into contact with an acid in an electrochemical cell to produce the concrete precursor and a liquid rich in the one or more metal ions, (b) A step of contacting the liquid rich in one or more metal ions with a base in the electrochemical cell to form a precipitate containing one or more metal ions and a liquid lacking one or more metal ions, Includes, The electrochemical cell comprises an anode reservoir containing an anode and the acid, and a cathode reservoir containing a cathode and the base, wherein the anode reservoir and the cathode reservoir are separated by a separator.

20. The method according to claim 19, wherein the separator is an anion exchange membrane.

21. The method according to claim 19, wherein the separator is a cation exchange membrane.

22. The method according to any one of claims 19 to 21, further comprising the step of regenerating the acid and the base in the electrochemical cell.

23. The method according to claim 13 or 19, further comprising the step of separating the concrete precursor from the liquid rich in one or more metal ions in step (a) before step (b).

24. The method according to claim 13 or 19, further comprising the step of repeating each of steps (a) to (b) at least once using sequential electrolysis.

25. The method according to claim 24, wherein the sequential electrolysis is carried out via continuous electrodistillation.

26. The method according to any one of claims 1 to 25, further comprising the step of separating the concrete precursor of step (a) and the liquid rich in one or more metal ions before step (b).

27. The method according to any one of claims 1 to 26, further comprising the step of heating the precipitate to produce a cement material.

28. A system for preparing concrete precursors, An electrochemical cell configured to prepare a concrete precursor, wherein the electrochemical cell comprises an anode reservoir containing an anode and an acid, and a cathode reservoir containing a cathode and a base, the anode reservoir and the cathode reservoir being separated by a separator, A contactor configured to introduce recycled concrete aggregate (RCA) containing one or more metal ions into an anode reservoir, wherein the anode reservoir is configured to contact the RCA with an acid to produce a concrete precursor and a liquid rich in one or more metal ions, and the cathode reservoir is configured to contact the liquid rich in one or more metal ions with a base to form a precipitate containing one or more metal ions and a liquid deficient in one or more metal ions, A first filtration system in contact with the anode reservoir, configured to filter and remove the concrete precursor from the anode reservoir, A second filtration system in contact with the cathode reservoir is configured to filter and remove the precipitate containing one or more metal ions from the cathode, A system equipped with these features.

29. The system according to claim 28, further comprising a tube connected from the anode reservoir to the cathode reservoir, configured to discharge hydrogen gas from the cathode reservoir and introduce hydrogen gas into the anode reservoir.

30. The system according to claim 28 or 29, further comprising a conductive material connected to the anode and configured to emit electrons from the anode and introduce the electrons into the cathode.

31. The system according to any one of claims 28 to 30, further comprising a valve configured to supply water to the anode reservoir.

32. The system according to any one of claims 28 to 31, wherein the first filtration system is further configured to filter the liquid rich in one or more metal ions from the concrete precursor and to introduce the liquid rich in one or more metal ions into the cathode reservoir.

33. The system according to any one of claims 28 to 32, wherein the separator is an anion exchange membrane or a cation exchange membrane.

34. The method according to any one of claims 1 to 27 or the system according to any one of claims 28 to 33, wherein the one or more metal ions are selected from ions of lithium, sodium, potassium, beryllium, magnesium, calcium, strontium, barium, radium, aluminum, gallium, indium, tin, thallium, lead, bismuth, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, cadmium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, and mercury.

35. The method or system according to any one of claims 1 to 34, wherein the one or more metal ions are selected from ions of sodium, potassium, magnesium, calcium, tin, lead, iron, cobalt, nickel, copper, zinc, palladium, silver, cadmium, platinum, and gold.

36. The method or system according to any one of claims 1 to 35, wherein the one or more metal ions are selected from sodium, potassium, magnesium, and calcium ions.

37. (a) A step of mixing the precipitate with one or more silicates to form a mixture, (b) A step of crushing the mixture to form fine particles, (c) A step of heating the fine particles to approximately 1,000°C to approximately 1,500°C for a certain period of time to provide cement, A method or system according to any one of claims 1 to 36, further comprising:

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