Production of cement and iron from non-carbonate materials

Abstract

Provided herein are methods and compositions for producing cement and iron from non-carbonate materials. Methods include beneficiating a non-carbonate staring material to provide a calcium-rich and an iron-rich fraction, and treating the two fractions to produce cement and iron compound, respectively.

Description

PRODUCTION OF CEMENT AND IRON FROM NON-CARBONATE MATERIALSCross-Reference to Related Applications

[0001] This application claims the benefit of priority to U.S. Provisional Application Number 63 / 640,767 filed on April 30, 2024, the entirety of which is incorporated herein by reference.Background

[0002] Cement is a material that underpins a substantial portion of modern infrastructure. The most common type of cement is ordinary Portland cement, which is used in the production of concrete, mortar, stucco, non-specialty grout, and other materials. As ubiquitous as cement is, there are many drawbacks inherent to it and its current methods of production. Portland cement is caustic, and its production requires high energy consumption in quarrying raw materials, manufacture, and transport. The production of Portland cement also releases a significant amount of greenhouse gases, approximately 8% of the global annual carbon dioxide emissions. Of these carbon dioxide emissions, approximately 60% come from the calcination of carbonate, and are unavoidable unless a non-carbonate (non-calcium carbonate) material is used as a starting material. Additionally, the Internal Energy Agency (IEA) has estimated that cement production will increase by 12-23% by 2050. Thus, there is a need in the cement production field to create new, useful, and environmentally friendly methods for the production of cement precursors and / or cement materials from non-carbonate materials.

[0003] Additionally, many non-carbonate materials that contain calcium also contain significant amounts of iron and / or aluminum. Concurrently, aluminum ore and iron ore reserves are increasingly scarce and / or low quality, and, as population grows, deposits without environmental, social, and governmental concerns may be especially scarce. Hence, there is a demand for providing pure forms of iron and aluminum compounds. Given the presence of many these minerals together with calcium, there is the potential to produce cement and iron from the same non-carbonate material, improving economies of scale.Summary of the Invention

[0004] In certain embodiments provided are methods for co-production of a cement material and iron from a non-carbonate material. The method may also include the production of an aluminum compound from the non-carbonate material. In certain preferred embodiments, the aluminum compound comprises metallic aluminum.

[0005] This invention also relates to a system and / or industrial plant for co-production of a cement material and iron from a non-carbonate material. The system and / or plant may also include the production of an aluminum compound from the non-carbonate material. In certain preferred embodiments, the aluminum compound comprises metallic aluminum.Brief Description of the Figures

[0006] Fig. 1 shows a method for co-production of a cement material and iron from a non-carbonate material.

[0007] Fig. 2 shows a general method for production of a cement material from a calcium-rich solid fraction.

[0008] Fig. 3 shows one example of the method according to Fig. 2.

[0009] Figs. 4-5 show examples of the method according to Figs. 2-3.

[0010] Fig. 6 shows a general method for production of iron from an iron-rich solid fraction.

[0011] Fig. 7 shows a general method for pre-treatment of the iron-rich solid fraction.

[0012] Figs. 8-9 show variations on the method of Fig. 6.

[0013] Figs. 10-11 shows examples of the method of Fig. 6.Detailed Description

[0014] In certain embodiments, provided herein are methods for co-production of a cement material and iron from a non-carbonate material. In general, and according to Fig. 1, the method comprises: a. providing a non-carbonate material comprising calcium and iron; b. beneficiating the non-carbonate material to provide a calcium-rich solid fraction and an iron-rich solid fraction, and further processing the solid fraction;c. creating a calcium-rich liquid fraction and a calcium-poor solid fraction from the calcium-rich solid fraction; i. separating the calcium-rich liquid fraction from the calcium-poor solid fraction; ii. precipitating a solid calcium compound from the calcium-rich liquid fraction to provide a calcium-depleted liquid fraction; iii. treating the solid calcium compound to produce a cement material; wherein further processing of the iron-rich solid fraction can optionally further comprise d. creating an iron-rich liquid fraction and an iron-poor solid fraction from the iron- rich solid fraction; i. separating the iron-rich liquid fraction from the iron-poor solid fraction; and ii. isolating iron compound from the iron-rich liquid fraction to produce an iron-depleted liquid fraction, and the iron.

[0015] For convenience, the invention will be described for processes in which both the calcium-rich solid fraction is processed to produce a cement material, the iron-rich solid fraction is processed to produce iron, but it will be understood that the description applies, where applicable, to simpler processes, e.g., processes not comprising processing the iron-rich liquid to produce iron but processing it in some other way. The following description of the embodiments of the invention is not intended to limit the invention to these embodiments but rather to enable a person skilled in the art to make and use this invention.A. Providing a Non-Carbonate Material

[0016] Providing a non-carbonate material serves as providing a starting material for the process. As used herein, "non-carbonate material" includes materials that contain low amounts of calcium carbonate and / or magnesium carbonate (e.g., limestone), such as less than 20% calcium carbonate and / or magnesium carbonate, or, preferably, less than 10% calcium carbonate and / or magnesium carbonate; generally, lower amounts of calcium carbonate and / or magnesium are preferred in order to avoid producing carbon dioxide in various steps;however, many materials, such as non-carbonate rocks and / or minerals, can contain some amount of calcium carbonate and / or magnesium carbonate and be suitable for use in the processes and apparatus described herein.

[0017] Non-carbonate materials can be rocks and / or minerals, or industrial waste, or combinations thereof. The non-carbonate material comprises calcium and iron. Preferred starting non-carbonate starting materials comprise at least 10% calcium, more preferably at least 15% calcium, and at least 5% iron, more preferably at least 10% iron, even more preferably at least 15% iron. Preferred starting materials comprise less than 30, 25, 20, 15, 10, 5, 2, or 1 % carbonate, such as less than 10% or less than 5%.

[0018] The starting, e.g., rock and / or mineral can be processed to provide particles in a desired size range. Any suitable process or processes may be used, such as crushing, grinding, and / or milling, and sieving or the like. Suitable size ranges include 1-500 pm, 5-300 pm, 10-200 pm, 20-130 pm, 45-90 pm, or a combination thereof. In a preferred embodiment the size range is 20-130 pm. In a more preferred embodiment, the size range is 45-90 pm.

[0019] In some variations the non-carbonate material comprises silicate rock, but may generally comprise any non-carbonate material, or materials, wherein the materials together, contain calcium, iron, and, optionally, silicon. Non-carbonate material may be found / chosen to additionally include any sets of desired compounds (and / or unknown compounds). In addition to calcium and iron, and optionally, silicon, the non-carbonate material may include other minerals and / or compounds. Examples include magnesium compounds (e.g., magnesium oxide, magnesium silicates), aluminum compounds (e.g., aluminum oxide, aluminates, aluminosilicates), silicon compounds (e.g., silicon dioxide, silicates, aluminosilicates). Sources of the non-carbonate mineral may include: mined rocks and / or minerals, quarry rocks and / or minerals, skarns, rock and / or mineral tailings, fly ash, slag, old cement, concrete, and industrial waste products.

[0020] More generally, suitable non-carbonate rocks and / or minerals include basalt, basaltic andesite, andesite, dacite, picrobasalt, foidite, feldspathoids, anorthosite, gabbros, diorites, tonalites, skarns, igneous rocks, metamorphic rocks, mafic rocks, and ultramafic rocks. Other suitable non-carbonate rocks and / or minerals include pyroxenes, pyroxenites, garnets, olivines, calc-olivines, micas, clay minerals, zeolites, scapolites, plagioclase feldspars, anorthite, igneous apatites, gypsum, or any combination thereof. Other suitable rocks and / or minerals will be apparent to those of skill in the art.B. Beneficiating the Non-Carbonate Material

[0021] The method includes beneficiating the non-carbonate material to provide calcium-rich solid fraction and iron-rich solid fraction. Beneficiating the starting material functions to increase the calcium concentration of the fraction used for making cement, increase the iron concentration of the fraction used for making an iron, decrease the calcium concentration of the fraction used for making an iron, and / or decrease the iron concentration of the fraction used for making a cement material. As an example, flotation, magnetic separation, and other physical and chemical separation methods may be used to separate the calcium-rich solid fraction from the iron-rich solid fraction.

[0022] The terms "calcium-rich" and "iron-rich" are relative terms that refer to the solid fractions after processing to decrease iron content of the starting material, and in so doing produce the iron-rich solid fraction, and the remaining fraction in which iron content has been decreased, which is the calcium-rich solid fraction; it is within the scope of this disclosure that the iron-rich solid fraction comprises calcium, in some cases in appreciable quantities, likewise, that the calcium-rich solid fraction can comprise iron, in some cases in appreciable quantities.C. Treating the Calcium-rich Solid Fraction

[0023] The calcium-rich solid fraction can be used to produce a cement material. In general, according to Fig. 2, this comprises: a. Creating a calcium-rich liquid fraction and a calcium-poor solid fraction from the calcium-rich solid fraction; b. separating the calcium-rich liquid fraction from the calcium-poor solid fraction; c. precipitating a solid calcium compound from the calcium-rich liquid fraction to provide a calcium-depleted liquid fraction; d. treating the solid calcium compound to produce a cement material; and e. optionally further treating the calcium-depleted liquid fraction.

[0024] As used herein "liquid fractions" may include liquid fractions, or liquid-like fractions (e.g. concentrated brines).Cl. Creating a Calcium-rich Liquid Fraction and a Calcium-poor Solid Fraction

[0025] Creating a calcium-rich liquid fraction and a calcium-poor solid fraction from the calcium-rich solid fraction functions to break down the starting material to allow separation of calcium compounds from non-calcium compounds, e.g., silica, silicates, or aluminosilicates.

[0026] This may include dissolving the starting material thereby dissolving at least a portion of the calcium compounds within the starting material, thereby creating a calcium-rich liquid fraction and calcium-depleted solid fraction. In this manner dissolving the starting material may partially dissolve the starting material such that one or more of silica, silicates, and / or aluminosilicates remain solid wherein other compounds (e.g., those attached to calcium) are dissolved. The calcium-poor solid fraction (silica, silicates, aluminosilicates) may be used as supplementary cementitious materials.

[0027] Dissolving the calcium-rich solid fraction may include adding a leaching agent. The leaching agent may comprise a single compound, multiple compounds, and / or a series of compounds. In certain embodiments, the leaching agent comprises a single compound, e.g., HCI. The leaching agent may function in, at least partially, dissolving the calcium-rich solid fraction. The leaching agent may be water, metal salts, acids, and / or oxidants. Generally, the leaching agent may have the limitation wherein the leaching agent dissolves calcium compounds in the calcium-rich solid fraction. In some variations, the leaching agent comprises replenishable compound(s), including those produced electrochemically or requiring a sustained voltage to persist (e.g. pH gradients from water electrolysis).

[0028] In one example, the leaching agent is an acid, i.e., a first acid. In certain embodiments, only one acid is used, e.g., only HCI is used. The first acid functions to dissolve calcium compounds within the calcium-rich solid fraction. Additionally, the first acid may dissolve non-silicate compounds in the material (e.g., metals and salts), thereby creating a calcium-depleted solid fraction, e.g., silicon compound-containing solid fraction and a mineralbased liquid fraction (calcium-rich liquid fraction). Alternatively, the first acid may dissolve the silicate material. The first acid is preferably a strong acid, but may alternatively comprise a weak acid or protons generated at an anode including from water spliting. In one variation, the first acid comprises hydrochloric acid (HCI). In one variation, the first acid consists essentially of HCI. In another variation, the first acid comprises hydroiodic acid (HI). Examples of other first acids may include: hydrobromic acid, nitric acid, silica, silicic acid, ammonium chloride andother ammonium halides, and hydronium ion produced via water electrolysis. In one variation, HCI may dissolve metals in the calcium-rich solid fraction, creating a metal rich liquid fraction (calcium-rich liquid fraction).

[0029] In certain embodiments, the calcium-rich solid fraction, e.g., rock and / or mineral material is contacted with a strong acid to form a pulp comprising the acid and rocks and / or minerals. Any suitable strong acid may be used, such as HCI, HBr, HI, H2SO4, or HNO3. In certain embodiments the strong acid comprises HCI; HCI may be the only strong acid used in the procedure. It will be appreciated that generally in such embodiments, other acids may be used for non-essential functions, such as cleaning equipment and the like, but the acid used to dissolve the calcium-rich solid fraction is HCI. HCI is particularly useful because it produces chlorides, e.g., calcium chlorides, which are useful starting materials for further steps in the process. HCI also lends itself to relatively simple regeneration at one or more points in the process. For convenience the remainder of the process will be described in terms of HCI; as will be apparent to one of skill in the art, if another acid is used in addition to or as an alternative to HCI, suitable adjustments may be made to accommodate the additional / alternative acid.

[0030] The calcium-rich solid fraction is dissolved in the hydrochloric acid (HCI). In certain embodiments, the proportion of strong acid that comprises HCI is at least 20, 30, 40, 50, 60, 70, 80, 90, 95, or 99% of the strong acid. In certain embodiments, 100% of the strong acid is HCI. Any suitable concentration of HCI may be used, such as 5-40%, 10-37%, 10-30%, 15- 35%, 17-23%, 20-30%, or about or exactly 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30%, such as about or exactly 20%. In preferred embodiments the HCI is 10-37%. In still more preferred embodiments the HCI is 15-35%. The ratio of starting material, such as solid rock and / or mineral, to leaching agent, such as liquid, for example acid, in the initial pulp may be any suitable ratio; it will be appreciated that some of the solid rock and / or mineral will begin dissolving in the acid immediately and that these ratios will change as solid dissolves into solution. Suitable initial ratios can be in the range of 5% solid / 95% liquid to 40% solid / 60% liquid, such as 10% solid / 90% liquid to 30% solid / 70% liquid; in a preferred embodiment 15% solid / 85% liquid to 25% solid / 75% liquid, such as 20% solid / 80% liquid.

[0031] The pulp is treated to cause dissolution of at least a sufficient amount of calcium compounds in the calcium-rich solid fraction to enter solution to provide a satisfactory final product, e.g., to be converted to clinker or cement, e.g., Portland cement. The leachingconditions (temperature, pressure, concentration, type of acid) may be optimized to selectively extract calcium, while other metals remain in a solid form.

[0032] In certain embodiments, at least 50, 60, 70, 80, 90, 95%, or 100% of calcium in the starting material enters solution, preferably at least 70%, more preferably at least 80%, even more preferably at least 90%. The treatment can occur in a process open to the atmosphere, or at least not pressurized; alternatively, the treatment may occur in a pressurized system. The treatment can include heating and / or maintaining the pulp at a temperature or range of temperatures for a certain duration. In general, duration of treatment and / or temperature may be used, to provide the desired dissolution. Suitable temperature ranges at which the pulp is maintained include 60-200 °C, 65-150 °C, 70-120 °C, 75-95 °C or 80-90° C; it will be appreciated that, due to presence of a high concentration of HCL and also as material dissolves in the liquid phase, boiling temperature for the HCI solution can be above 100 °C. When the system is pressurized, the boiling temperature for the HCI solution can be controlled based on the system pressure.

[0033] Any suitable duration of treatment may be used. This can depend, to some degree, on the calcium content of the calcium-rich solid fraction; materials with lower calcium content can require longer treatment to achieve a desired amount of calcium salts in solution. Thus, the duration of treatment may be at least 1, 2, 3, 4, 5, 6, 7, 8, or 10 hours and / or not more than 2, 3, 4, 5, 6, 7, 8, 10, 12, 15, 20, 24, 30, 36, 40, 48, 60, or 72 hours. In certain embodiments, the duration can be 2-24 hours, such as 4-18 hours or even 4-12 hours or less. In certain embodiments, the duration may be 6-72 hours, such as 4-48 hours, or 4-36 hours, or 4- 24 hours.

[0034] The pulp can be agitated during treatment, e.g., stirred, for example stirred at 10- 1000 RPM, 20-800 RPM, 50-500 RPM, 50-400 RPM, or 100-300 RPM. In preferred embodiments, the pulp is stirred at 50-400 RPM, more preferably at 100-300 RPM. Other methods of agitation as known in the art may be used. A calcium-depleted solid fraction and a calcium-rich liquid fraction are produced from the pulp. Some of the acid, e.g., HCI, may move into gas or vapor phase during the process, and can be recaptured and returned for use as leaching agent.

[0035] In some variations, adding a first acid may comprise adding an organic or biogenic acid (e.g., oxalic acid). Adding an organic first acid may selectively leach the calcium- rich solid fraction, thereby enabling selective extraction of metals. Examples of organic acidsthat may be incorporated include: Propionic acid, Butyric acid, Citric acid, Succinic acid, Malic acid, Tartaric acid, and Oxalic acid. In one example, the first organic acid may selectively leach all minerals from the calcium-rich solid fraction (e.g., by thermal decomposition).

[0036] In some variations, microbes may be implemented to produce the first organic acid. Microbes may be engineered to produce organic acids by utilizing CO2 as a carbon source and therefore CO2 produced by decomposing the organic acid in subsequent steps may be recycled or mitigated by feeding this CO2 to the microbes.C2. Separating the Calcium-rich Liquid Fraction from the Calcium-poor Solid Fraction

[0037] The calcium-rich liquid fraction is separated from the calcium-poor solid fraction, thus separating the metals in the calcium-rich liquid fraction from the calcium-poor solid fraction, which may be used as supplementary cementitious materials. Any suitable method of separation may be implemented. In some variations may further include washing, rinsing, and / or drying the calcium-poor solid fraction.

[0038] In some variations, separating the calcium-rich liquid fraction from the calcium- poor solid fraction is accomplished by filtration. In one implementation, vacuum filtration is used, wherein a pressure difference is used to flow fluid through a filter. In another implementation, hot filtration is used, wherein the solution is heated and then forced through a filter. In another implementation cold filtration is used, wherein the solution is initially cooled down to crystallize additional components (e.g., SCM), and then filtered. In some variations, a filtration press is implemented for separating the solid fraction. The filter press may enable stacking of multiple filter elements and allow the filter to be easily opened to remove the filtered solids. A filter press may be implemented with any desired filtering process as described above.

[0039] Separating the calcium-depleted solid fraction from the calcium-rich liquid fraction may significantly deplete the volume of the calcium-rich liquid fraction. Therefore, either before this happens or once this occurs, additional solution may be added to the calcium-rich fraction to replenish the volume. This may occur at any separation and / or precipitation step. Additional solution may be added at any step to maintain a desired working volume. The filtrate (calcium-poor solid fraction) may be washed to recover any remaining calcium-rich liquid fraction, or any calcium compounds that have precipitated from thecalcium-rich liquid fraction during processing. The number of washes and the amount of solvent used per wash can be determined based on the desired concentration of the calcium- rich liquid fraction, the desired calcium recovery, or any other factors apparent to one of the art.C3. Optionally Treating the Calcium-Rich Liquid Fraction

[0040] Depending on the type of solid calcium compound precipitated, it may be useful or necessary to optionally treat the calcium-rich liquid fraction to precipitate or otherwise remove any metal salts that could precipitate as solid metal compounds instead of the solid calcium compound, or could co-precipitate with the solid calcium compound, prior to precipitating a solid calcium compound. This may be advantageous when it is possible to precipitate the metal salts as solid metal compounds using less expensive or milder reagents than required for precipitating the solid calcium compound, or at a desired temperature or concentration that is different than the temperature or concentration used to precipitate the solid calcium compound. In some embodiments, the solid metal compounds include metal oxides, hydroxides, oxy hydroxi des, sulfates, carbonates, chlorides, or combinations thereof.

[0041] Precipitating the solid metal compounds may serve to regenerate a portion of the leaching agent or provide a compound that may be treated to regenerate a portion of the leaching agent. A thermal, chemical, electrical, or electrochemical process may be implemented in regenerating the leaching agents.

[0042] The metal salts can be precipitated as solid metal compounds simultaneously, or in a stepwise manner, using any processes or reagents known in the art, including altering temperature, concentration, or pH, or by driving a decomposition reaction. As an example, the pH may be increased to precipitate iron, aluminum, and / or magnesium oxides, hydroxides, or oxyhydroxides simultaneously or in a stepwise manner.

[0043] As a specific example, when the solid calcium compound is calcium hydroxide (Ca(OH)2) or calcium carbonate (CaCO3, including its hydrates), if one were to attempt precipitation before removing one or more of the metal salts, additional solid metal compounds may precipitate instead of calcium hydroxide or calcium carbonate, or with calcium hydroxide or calcium carbonate, either as separate compounds or as mixed metal compounds. As an example, when the calcium-rich liquid fraction also comprises iron, aluminum, and / or magnesium salts, solid iron, aluminum and / or magnesium compounds, especially iron,aluminum, and / or magnesium oxides, hydroxides, or oxyhydroxides may precipitate instead of calcium hydroxide or calcium carbonate, or co-precipitate with calcium hydroxide or calcium carbonate, either as separate compounds or as mixed metal compounds comprising calcium and one or more of iron, aluminum, and / or magnesium. Hence, it may be beneficial to remove one or more of the metal salts before forming calcium hydroxide or calcium carbonate. The following examples illustrate removal of one or more calcium salts.

[0044] As another example, when aluminum salts are present, the aluminum salts, e.g. aluminum chloride, or hydrates thereof, including aluminum chloride hexahydrate (AICI3-6H2O), may be precipitated or (re)crystallized first and removed, by cooling the solution, removing water, or adding HCI to induce precipitation via the common ion affect, or any combination thereof. It will be apparent to one of ordinary skill in the art that other aluminum salts may be selectively precipitated in a similar fashion. Other salts may then be precipitated or (re)crystallized in a stepwise manner, or together, or, alternatively, the salt(s) are not removed before precipitating the solid calcium compound.

[0045] As another specific example, when the solid calcium compound is calcium hydroxide (Ca(OH)2) or calcium carbonate (CaCO3, including its hydrates), the iron, aluminum, and / or magnesium salts, may be precipitated as iron, aluminum, and / or magnesium oxides, hydroxides, or oxyhydroxides simultaneously or in a stepwise manner.C4. Precipitating a Solid Calcium Compound

[0046] Precipitating a solid calcium compound serves to isolate a calcium compound for producing a cement material, yielding a calcium-depleted liquid fraction.

[0047] In some embodiments, precipitating the solid calcium compound makes use of base to precipitate calcium hydroxide (Ca(OH)2). The base may be an alkali hydroxide, including sodium hydroxide (NaOH). In the case where the solid calcium compound is treated with a base, this may result in the formation of a metal salt, which can later be treated to regenerate the base. In the case where base is used to precipitate calcium hydroxide, it may be beneficial to separate other metal salts that may precipitate upon addition of base, e.g. iron salts, aluminum salts, magnesium salts, before precipitation of calcium hydroxide, as described above.

[0048] In other embodiments, precipitating the solid calcium compound makes use of a combination of base and CO2 to precipitate calcium carbonate (CaCOs, including its hydrates).The reaction conditions (time, temperature, concentration) and degree of hydration may be controlled to facilitate separation of the solid calcium compound from the calcium-depleted liquid fraction. The base may be an alkali hydroxide, including alkali hydroxide (e.g. NaOH), or ammonia (NH3). In the case where the solid calcium compound is treated with a base, this may result in the formation of a metal or ammonium salt, which can later be treated to regenerate the base. In the case where base is used to precipitate calcium carbonate, it may be beneficial to separate other metal salts that may precipitate upon addition of base, e.g. iron salts, aluminum salts, magnesium salts, before precipitation of calcium carbonate, as described above.

[0049] In still other embodiments, precipitating the solid calcium compound makes use of a sulfate source to precipitate calcium sulfate (CaSO4, including its hydrates). The sulfate source may be a metal sulfate or, more preferably, sulfuric acid. The reaction conditions (time, temperature, concentration) and degree of hydration may be controlled to facilitate separation of the solid calcium compound from the calcium-depleted liquid fraction. When the leaching agent is hydrochloric acid and the sulfate source is sulfuric acid, calcium chloride may react with sulfuric acid following to precipitate calcium sulfate according to the following reaction:CaCI2+ H2SO4 - CaSO4(s) + 2 HCI (aq)

[0050] In some embodiments, the reaction temperature is controlled to allow the evaporation, and collection, of the acid, e.g. HCI, from the calcium-depleted liquid fraction. Alternatively, the acid, e.g. HCI, may remain in solution. The presence of HCI in solution may be advantageous for any further treatment of the calcium-depleted liquid fraction, e.g. precipitation or (re)crystallization of any other metal chlorides using the common ion effect.C5. Treating the Solid Calcium Compound to Produce a Cement Material

[0051] The solid calcium compound may be separated from the calcium-depleted liquid fraction using any of the aforementioned techniques or those known to one of ordinary skill in the art.

[0052] In some embodiments, the cement material is calcium oxide (CaO) or calcium hydroxide. This can be accomplished using methods known in the art. In the case when Ca(OH)2 is produced, the further treatment may simply involve isolating the solid calcium compound from the calcium-depleted liquid fraction. In the case where calcium carbonate isprecipitated, it can be calcined to result in the formation of calcium oxide, or treatment with a strong alkaline solution to produce calcium hydroxide.

[0053] In the case where the solid calcium compound is calcium sulfate, it can be thermally decomposed to produce a gas including SO2 and / or SO3; such a reaction may also produce O2. In some embodiments, the solid calcium compound is heated in the presence of a reducing agent. The reducing agent can be any suitable reducing agent or combination of reducing agents, including hydrogen, biochar, natural gas, coal, elemental sulfur, H2S, or metallurgical coke. Without being bound by theory, it is believed that the presence of a reducing agent can significantly lower the temperature needed for decomposition of calcium sulfate, which may occur according to one or more of the following reactions (where R is a reducing agent):

[0054] In other embodiments, the cement material is a blended cement, where calcium oxide or calcium hydroxide is blended with SCM to produce a blended cement, akin to the cement used in Roman concrete. The precise blending ratio of calcium oxide or calcium hydroxide to SCM may be determined based on the desired properties of the blended cement, as is known in the art.

[0055] In still other embodiments, the solid calcium compound is clinkered to produce a cement material, such as a calcium silicate cement, calcium aluminate cement, or calcium sulfoaluminate cement. In these embodiments, the solid calcium compound is heated in the presence of one or more of alumina or silica, and, optionally, exogenous flux, such as exogenous flux containing aluminum, e.g., AI(OH)3 and / or iron, e.g., Fe(OH)x, and further optionally, a reducing agent. Generally, the flux is not necessary but may be added at this step for convenience. In certain embodiments, some or all of the silica or alumina, e.g., at least 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 98, 99%, or 100%, is produced from non-carbonate materials, e.g., non-carbonate rocks and / or minerals, such as in an earlier step in the process, e.g., production of SCM (pozzolan) as described herein. In certain embodiments, some or all of the exogenous flux, e.g., at least 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 98, 99% of the flux, or 100% of the flux, is iron and aluminum oxides, hydroxides, and potentially other suitable compounds,produced from non-carbonate rocks and / or minerals, such as in an earlier step in the process, e.g., precipitated as insoluble salts from a calcium-rich fraction, as described herein. Generally, the reducing agent is not necessary but may be added at this step for convenience. In certain embodiments, some or all of the reducing agent, e.g., at least 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 98, 99%, or 100%, is produced from an earlier step in the process. It will be appreciated that the solid calcium compound can comprise one or more substances that can act as a flux, but, generally, it is preferable to add exogenous flux. Heating may be performed in a single step, at a sufficiently high temperature to both decompose the solid calcium compound and clinker, e.g., sinter, resulting compounds with flux.

[0056] In preferred embodiments, the solid calcium compound is clinkered in the presence of silica and, optionally a flux, and further optionally, a reducing agent, thus forming Portland cement clinker comprising dicalcium silicate and tricalcium silicate; in some cases the clinker also comprises tricalcium aluminate and / or tetracalcium al umi noferrite. If intermediate temperatures are used, a temperature may be, e.g., 900-1100 °C, such as 950-1050 °C; a temperature may be, e.g., 1100-1300 °C, such as 1150-1250 °C; a temperature may be, e.g., 1400-1600 °C, such as 1450-1550 °C In an exemplary embodiment, temperatures are, successively, 850, 1000, 1200, and 1500 °C, held for 1 hour each. These are merely exemplary, and one of skill in the art can select optimal temperatures and durations through routine experimentation.

[0057] When the solid calcium compound comprises calcium sulfate, the clinkering may be performed in a stepwise fashion, or in a single step. As an example, calcium sulfate may first undergo decomposition to yield calcium oxide as described above. As another example, calcium sulfate may undergo decomposition in the presence of silica, and optionally, a reducing agent (R), to provide an intermediate calcium silicate, such as dicalcium silicate. Such a reaction may occur according to one or more of the following reactions:2 CaSO4 + SiO2-> Ca2SiO4 + 2 SO2 + O2 2 CaSO4 + SiO2-> Ca2SiO4 + 2 SO33 CaSC + CaS 4 CaO + 4 SO2

[0058] The dicalcium silicate may then react with calcium oxide to form tricalcium silicate as described above. The clinker thus produced comprises hydraulic calcium silicates, such as at least di- and tricalcium silicates; conditions of the various steps (e.g., Ca:Si ratio for dechlorinating and producing clinker, flux makeup to produce clinker, etc.) can be adjusted to produce clinker with di- and tricalcium silicates in desired proportions, such as 40-70% tricalcium silicate (C3S), preferably 50-65%, such as 52-63%; and 10-35% dicalcium silicate (C2S), such as 15-25%. The clinker can also comprise tricalcium aluminate, e.g., at 5-12%, and / or tetracalcium aluminoferrite (C4AF), e.g., at 6-12%. The process can further comprise processing the clinker to produce cement, e.g., Portland cement, such as OPC. The cement thus produced can be used in producing concrete, e.g., by mixing with aggregates and water, and, in some cases, mixing with SCM. The aggregates and / or SCM may also be produced from the nonlimestone material. Seting and hardening are generally similar or identical to what is found for conventionally-produced cements of the same makeup, e.g., cements produced by calcining limestone then sintering the product. The processing can include sizing, e.g., by crushing, grinding, or milling and the like and screening, and can also include addition of one or more additional substances, e.g., gypsum.C6. Optionally Further Treating the Calcium-Depleted Liquid Fraction

[0059] The calcium-depleted liquid fraction may contain additional metal salts. As an example, when the non-carbonate material comprises calcium aluminosilicates such as anorthite, the calcium-depleted liquid fraction may contain one or more of aluminum salts, iron salts, magnesium salts, and / or sodium salts. In some embodiments, further treating the calcium-depleted liquid fraction serves to isolate solid metal compounds from the metal salts.

[0060] The solid metal compounds may be precipitated by (re)crysta llizi ng the metal salts as a solid metal compound, or by reacting the metal salts with a reagent to form a solid metal compound through one or more chemical reactions. In some embodiments, the solid metal compounds include metal oxides, hydroxides, oxy hydroxi des, sulfates, carbonates, chlorides, or combinations thereof. Precipitating the solid metal compounds may serve to regenerate a portion of the leaching agent or provide a compound that may be treated toregenerate a portion of the leaching agent. A thermal, chemical, electrical, or electrochemical process may be implemented in regenerating the leaching agents.

[0061] When multiple salts are present, they may be precipitated or (re)crysta I lized in a stepwise fashion according to their solubility, or, alternatively precipitated or (re)crysta llized together. One or more of the metal salts may be isolated by further treating the calcium- depleted liquid fraction to precipitate solid metal compounds. Alternatively, only some of these salts may be isolated as solid metal compounds, and the remaining salts can be recycled to any leaching step used in creating the calcium-rich liquid fraction. As another alternative, when this step is not employed, any remaining salts can be recycled to any leaching step used in creating the calcium-rich liquid fraction; this may be particularly advantageous when the concentration of other metal salts is minimal.

[0062] Precipitation or (re)crystallization may be induced varying reaction conditions, such as the temperature, by heating or cooling to reduce solubility, by removing water to adjust concentration, adding any additional reagents to induce precipitation through, for example, the common ion effect, or any combination thereof. In some embodiments, a seeded( recrystallization is used to aid (re)crystallization. In some embodiments, additional reagents are used to induce precipitation through the common ion effect; these additional reagents can comprise additional salts, or acids sharing a common ion. As an example, when the leaching agent comprises HCI, additional HCI may be added, or, if generated during the precipitation of the solid calcium compound, additional HCI may be present.

[0063] As an example, when aluminum salts, iron salts, magnesium salts, and, optionally, sodium salts are present, the aluminum salts, e.g. aluminum chloride, or hydrates thereof, including aluminum chloride hexahydrate (AICI3-6H2O), may be precipitated or (re)crysta II ized first and removed, by cooling the solution, removing water, or adding HCI to induce precipitation via the common ion affect, or any combination thereof. It will be apparent to one of ordinary skill in the art that other aluminum salts may be selectively precipitated in a similar fashion. Other salts may then be precipitated or (re)crystallized in a stepwise manner, or together, or, alternatively, the salt(s) are not removed and instead recycled to any leaching step used for creating the calcium-rich liquid fraction.

[0064] After aluminum chloride hexahydrate, or another aluminum salt is precipitated, it may be pyrohydrolyzed, calcined, or otherwise decomposed to give aluminum hydroxide, aluminum oxyhydroxide, aluminum oxide, or a combination thereof. This may result in theregeneration of the leaching agent, e.g. HCI, or production of a gas, e.g. SO2, which may be further treated to regenerate the leaching agent. When the gas is SO2, such a regeneration step may be achieved using the contact process, using electrochemistry, including the use of an SO2 depolarized electrode, such as a SO2 depolarized anode, or using an oxidizing agent, e.g. Cb; the resulting aluminum compound may be further processed to produce metallic aluminum, e.g. via Hall-Heroult process. In some embodiments, the aluminum salt is reacted to regenerate HCI and form another aluminum salt; as an example, the aluminum salt may be treated with H2SO4 to regenerate HCI and form aluminum sulfate or bisulfate, which then may be further processed to produce metallic aluminum. Other salts, e.g. iron salts, magnesium salts, and sodium salts, and residual aluminum salts, if present, may undergo analogous processing to regenerate the leaching agent.

[0065] Alternatively, when aluminum salts, iron salts, magnesium salts, and sodium salts are present, the salts may be precipitated or (re)crysta I lized together as mixed salts, by cooling the solution, removing water, or adding HCI to induce precipitation via the common ion affect, or any combination thereof. It will be apparent to one of ordinary skill in the art that other aluminum salts may be selectively precipitated in a similar fashion.

[0066] The mixed salts may be pyrohydrolyzed, calcined, or otherwise decomposed to give their corresponding oxides, oxyhydroxides, or oxides. This may result in the regeneration of the leaching agent, e.g. HCI, or production of a gas, e.g. SO2, which may be further treated to regenerate the leaching agent as described above. In some embodiments, the mixed salts are reacted to regenerate HCI and form other mixed salts; as an example, the mixed salts may be treated with H2SO4 to regenerate HCI and form metal sulfate or bisulfate salts.

[0067] In some embodiments, one or more of the above salt(s), or some of the above salt(s) are not precipitated or (re)crysta I lized, but instead are processed from solution, e.g. using spray pyrolysis. The mixed salts may be pyrohydrolyzed, calcined, or otherwise decomposed to give their corresponding oxides, oxyhydroxides, oxides, or a combination thereof. This may result in the regeneration of the leaching agent, e.g. HCI, or production of a gas, e.g. SO2, which may be further treated to regenerate the leaching agent. When the gas is SO2, such a regeneration step may be achieved using the contact process, using electrochemistry, including the use of an SO2 depolarized electrode, such as a SO2 depolarized anode, or using an oxidizing agent, e.g. CI2. When using an oxidizing agent such as CI2, SO2 and CI2 may react to form SO2CI2, which may hydrolyze to form H2SO4 and HCI, or, alternatively,S02 and CI2 may react in the presence of water to form H2SO4 and HCI. H2SO4 and HCI may be separated by, for example, distillation.

[0068] In general, the reaction conditions (temperature, water content) of the spray pyrolysis or pyro hydro lysis, calcination, or decomposition steps may be chosen so that all salts are pyrohydrolyzed, calcined or otherwise decomposed. For example, the reaction conditions may be chosen so some salts, e.g. one or more of iron, aluminum, and magnesium salts are pyrohydrolyzed, calcined, or otherwise decomposed, but other salts, e.g. sodium salts, are not, but instead remain in a soluble form. In this case, the unreacted salts can be separated through any suitable method, including washing or rinsing the solid product.

[0069] In still other embodiments, the calcium-depleted liquid fraction is processed to convert the metal salts to other metal salts, for the purpose of enriching an iron-rich liquid fraction created during the treatment of the iron rich fraction, or otherwise processing the remaining salts with the salts present in the iron-rich liquid fraction. As an example, when the calcium-depleted fraction comprises aluminum chloride, iron chloride, and sodium chloride, these salts may be treated with H2SO4 to regenerate HCI and form metal sulfate or bisulfate salts. As a variation on this example, when the calcium-depleted fraction comprises aluminum chloride, iron chloride, and sodium chloride, aluminum chloride may be precipitated first, and the remaining iron salts, magnesium salts, sodium salts, and residual aluminum salts, if present, may be treated with H2SO4 to regenerate HCI and form metal sulfate or bisulfate salts. The liquid fraction may then be used to enrich an iron-rich liquid fraction created during the treatment of the iron rich fraction, or otherwise processing the remaining salts with the salts present in the iron-rich liquid fraction.

[0070] In some embodiments, when the solid calcium compound is Ca(OH)2, which is precipitated using a base, a salt (e.g. NaCI when NaOH is the base) may remain in the calcium- depleted liquid fraction. The base and / or acid may be regenerated from the salt using any suitable electrochemical process, including the chlor-alkali process, or the use of a hydrogen depolarized anode, as is known in the art, or a thermal process, as is known in the art.

[0071] In some other embodiments, when the solid calcium compound is CaCO3 is precipitated using a base, a salt (e.g. NaCI when NaOH is the base, or NH4CI when NH3 and / or NH4OH is the base) may remain in the calcium-depleted liquid fraction. The base and / or acid may be regenerated from the salt using any suitable electrochemical process, including thechlor-alkali process, or the use of a hydrogen depolarized anode to regenerate acid and / or base, as is known in the art, or a thermal process, as is known in the art.Exemplary Embodiments

[0072] Fig. 3 shows one example of the treatment of the calcium-rich solid fraction, where the leaching agent is hydrochloric acid, and the solid calcium compound is calcium sulfate, precipitated by addition of sulfuric acid. The calcium sulfate is then clinkered in the anhydrite process to produce a cement material. In a preferred embodiment, the cement material is ordinary Portland cement.

[0073] Fig. 4 shows a specific example of the method of Fig. 3, wherein the further treatment of the calcium-depleted liquid fraction comprises precipitating aluminum chloride hexahydrate, then calcining, pyrohydrolyzing, or otherwise decomposing the aluminum chloride hexahydrate to aluminum oxide to regenerate the leaching agent. While shown as aluminum oxide, other forms, such as aluminum hydroxides, oxyhydroxides, or oxides may be formed. The residual calcium-depleted and aluminum-depleted liquid fraction undergoes the spray pyrohydrolysis of residual aluminum chloride, iron chloride, and magnesium chloride to regenerate the remaining leaching agent.

[0074] Fig. 5 shows another specific example of the method of Fig. 3, wherein the further treatment of the calcium-depleted liquid fraction comprises spray pyrohydrolysis of aluminum chloride, iron chloride, and magnesium chloride to regenerate the remaining leaching agent.D. Treating the Iron-Rich Solid Fraction

[0075] The iron-rich solid fraction is further processed, as well. Any suitable processing may be used. In certain embodiments, the iron-rich solid fraction is ultimately processed to produce iron, as shown in Fig. 6. In general, this comprises: a. creating an iron-rich liquid fraction and an iron-poor solid fraction from the iron- rich solid fraction; b. separating the iron-rich liquid fraction from the iron-poor solid fraction; c. isolating iron from the iron-rich solid fraction,

[0076] In certain embodiments, the iron-rich liquid fraction comprises one or more iron compounds, e.g., ionic iron compounds, and is further treated to produce iron from the one or more iron compounds. As above, herein "liquid fractions" may include liquid fractions, or liquid-like fractions, including concentrated brines.

[0077] In general, the iron-rich solid fraction may undergo pre-treatment to create a pre-treated iron-rich solid fraction and a pre-treated iron-poor fraction, as shown in Fig. 7. This pre-treatment occurs prior to creating an iron-rich liquid fraction and an iron-poor solid fraction from the iron-rich solid fraction. The pre-treated iron-poor fraction may comprise one or more of aluminum compounds, magnesium compounds, and / or calcium compounds. This pre-treated iron-rich solid fraction may then proceed as the iron-rich solid fraction for further processing.

[0078] In one embodiment, pre-treatment can be accomplished by hydrothermal carbonation of the iron-rich solid fraction. Without being bound by theory, hydrothermal carbonation can result in the formation of (alumino)silicates, and one or more of magnesium and calcium carbonates, in addition to ferrous and / or ferric oxides, oxyhydroxides, hydroxides, and / or carbonates. The ferrous and / or ferric oxides, oxyhydroxides, hydroxides, and / or carbonates can be separated from other solid compounds, including solid calcium and / or magnesium carbonate, using the same methods described above for beneficiation in general. Alternatively, the calcium and / or magnesium carbonates can be separated using a pCO2 swing, whereby aqueous calcium and / or magnesium carbonates are dissolved at high pCO2 (low pH), then separated from insoluble iron compounds and / or (alumino)silicates, followed by reprecipitation at low pCO2 (higher pH).

[0079] In some embodiments, the iron-rich solid fraction may comprise first and second iron-rich fractions, which may be separated. This can be accomplished by beneficiation, using one or more of the methods described below with respect to beneficiating the non-carbonate material prior to leaching the second iron-rich fraction. In such a variation, shown in Fig. 8, treating the iron-rich solid fraction would comprise: a. separating the first iron-rich fraction from the second iron-rich fraction, wherein the second iron-rich fraction comprises one or more ionic iron compounds; b. creating an iron-rich liquid fraction and an iron-poor solid fraction from the second iron-rich fraction c. separating the iron-rich liquid fraction and the iron-poor solid fraction; andd. isolating iron from the iron-rich liquid fraction to produce iron and an iron- depleted liquid fraction.

[0080] Alternatively, separating the first and second iron-rich fractions can be achieved during the creating the iron-rich liquid fraction and the iron-poor solid fraction. In such a variation, shown in Fig. 9, treating the iron-rich solid fraction would comprise: a. creating an iron-rich liquid fraction and an iron-poor solid fraction from the second iron-rich fraction; b. separating the iron-rich liquid fraction from the iron-poor solid fraction and the first iron-rich fraction; i. separating the iron-poor solid fraction and the first iron-rich fraction; c. isolating iron from the iron-rich liquid fraction to produce an iron-depleted liquid fraction and iron.

[0081] This may be particularly advantageous when the first and second iron-rich fractions exhibit different reactivity. As one example, the first iron-rich fraction may not be leached by the leaching agent, and may remain solid, while the second iron-rich fraction may be leached by the leaching agent. The first iron-rich fractions and the iron-poor solid fractions may be separated from the iron-rich liquid fraction, and then undergo further separation to separate them from the iron-poor solid fractions using any suitable separation technique, such as those described above for beneficiation.

[0082] In a specific embodiment, the iron-rich solid fraction includes a first iron-rich fraction, e.g. pyroxenes, and a second iron-rich fraction, e.g. olivines; the iron-rich solid fraction may contain additional phases, minerals, and / or compounds. Without being bound by theory, it is believed that the pyroxenes may be more resistant to leaching by a leaching agent, e.g.H2SO4, than other phases, e.g. olivines, which may be preferentially leached. The first iron-rich fraction may then be separated from an iron-poor solid fraction using any suitable separation technique, such as those described above for beneficiation.

[0083] Still alternatively, not shown, the first iron-rich fractions may undergo processing including leaching by a leaching agent, while the second iron-rich fractions may not be leached by the leaching agent; the iron-rich fraction may be separated from the second iron-rich fraction using filtration or other techniques apparent to those of skill in the art.DI. Creating an Iron-Rich Liquid fraction and an Iron-Poor Solid Fraction

[0084] Creating an iron-rich liquid fraction and an iron-poor solid fraction from the iron- rich solid fraction (or second iron-rich fraction when applicable) functions to break down the starting material to allow separation of iron compounds from non-iron compounds, e.g., silica, silicates, or aluminosilicates.

[0085] This may include dissolving the starting material thereby dissolving at least a portion of the iron compounds within the starting material, thereby creating an iron-rich liquid fraction and iron-depleted solid fraction. In this manner dissolving the starting material may partially dissolve the starting material such that one or more of silica, silicates, and / or aluminosilicates remain solid wherein other compounds (e.g., those attached to iron) are dissolved. The iron-poor solid fraction (silica, silicates, aluminosilicates) may also be used as supplementary cementitious materials.

[0086] Dissolving the iron-rich solid fraction may include adding a leaching agent. The leaching agent may comprise a single compound, multiple compounds, and / or a series of compounds. In certain embodiments, the leaching agent comprises a single compound, e.g., H2SO4. The leaching agent may function in, at least partially, dissolving the iron-rich solid fraction. The leaching agent may be water, metal salts, acids, and / or oxidants. Generally, the leaching agent may have the limitation wherein the leaching agent dissolves iron compounds in the iron-rich solid fraction. In some variations, the leaching agent comprises replenishable compound(s).

[0087] In one example, the leaching agent is an acid, i.e., a first acid. In certain embodiments, only one acid is used, e.g., only H2SO4 is used. The first acid functions to dissolve iron compounds within the iron-rich solid fraction. Additionally, the first acid may dissolve non-silicate compounds in the material (e.g., metals and salts), thereby creating an iron-depleted solid fraction, e.g., silicon compound-containing solid fraction and a mineralbased liquid fraction (iron-rich liquid fraction). Alternatively, the first acid may dissolve the silicate material. The first acid is preferably a strong acid, but may alternatively comprise a weak acid or protons generated at an anode including from water spliting. In one variation, the first acid comprises sulfuric acid (H2SO4). In one variation, the first acid consists essentially of H2SO4. In another variation, the first acid comprises hydroiodic acid (HI). Examples of other first acids may include: hydrobromic acid, nitric acid, and hydronium ion produced via waterelectrolysis. In one variation, H2SO4may dissolve metals in the iron-rich solid fraction, creating a metal rich liquid fraction (iron-rich liquid fraction).

[0088] In certain embodiments, the iron-rich solid fraction, e.g., rock and / or mineral material is contacted with a strong acid to form a pulp comprising the acid and rocks and / or minerals. Any suitable strong acid may be used, such as H2SO4, HBr, HI, H2SO4, or HNO3. In certain embodiments the strong acid comprises H2SO4; H2SO4 may be the only strong acid used in the procedure. It will be appreciated that generally in such embodiments, other acids may be used for non-essential functions, such as cleaning equipment and the like, but the acid used to dissolve the iron-rich solid fraction is H2SO4. H2SO4is particularly useful because it produces chlorides, e.g., iron chlorides, which are useful starting materials for further steps in the process. H2SO4 also lends itself to relatively simple regeneration at one or more points in the process. For convenience the remainder of the process will be described in terms of H2SO4; as will be apparent to one of skill in the art, if another acid is used in addition to or as an alternative to H2SO4, suitable adjustments may be made to accommodate the additional / alternative acid.

[0089] The iron-rich solid fraction is dissolved in the sulfuric acid (H2SO4). In certain embodiments, the proportion of strong acid that comprises H2SO4 is at least 20, 30, 40, 50, 60, 70, 80, 90, 95, or 99% of the strong acid. In certain embodiments, 100% of the strong acid is H2SO4. Any suitable concentration of H2SO4 may be used, such as 5-98%, 10-98%, 10-98%, or about or exactly 98%. In preferred embodiments the H2SO4 concentration is 98%. The ratio of starting material, such as solid rock and / or mineral, to leaching agent, such as liquid, for example acid, in the initial pulp may be any suitable ratio; it will be appreciated that some of the solid rock and / or mineral will begin dissolving in the acid immediately and that these ratios will change as solid dissolves into solution. Suitable initial ratios can be in the range of 5% solid / 95% liquid to 40% solid / 60% liquid, such as 10% solid / 90% liquid to 30% solid / 70% liquid; in a preferred embodiment 15% solid / 85% liquid to 25% solid / 75% liquid, such as 20% solid / 80% liquid.

[0090] The pulp is treated to cause dissolution of at least a sufficient amount of iron compounds in the iron-rich solid fraction to enter solution to provide a satisfactory final product, e.g., to be converted to clinker or cement, e.g., Portland cement. The leaching conditions (temperature, pressure, concentration, type of acid) may be optimized to selectively extract iron, while other metals remain in a solid form.

[0091] In certain embodiments, at least 50, 60, 70, 80, 90, 95%, or 100% of iron in the starting material enters solution, preferably at least 70%, more preferably at least 80%, even more preferably at least 90%. The treatment can occur in a process open to the atmosphere, or at least not pressurized; alternatively, the treatment may occur in a pressurized system. The treatment can include heating and / or maintaining the pulp at a temperature or range of temperatures for a certain duration. In general, duration of treatment and / or temperature may be used, to provide the desired dissolution. Suitable temperature ranges at which the pulp is maintained include 60-200 °C, 65-150 °C, 70-120 °C, 75-95 °C or 80-90° C; it will be appreciated that, due to presence of a high concentration of H2SO4 and also as material dissolves in the liquid phase, boiling temperature for the H2SO4 solution can be above 100 °C. When the system is pressurized, the boiling temperature for the H2SO4 solution can be controlled based on the system pressure.

[0092] Any suitable duration of treatment may be used. This can depend, to some degree, on the iron content of the iron-rich solid fraction; materials with lower iron content can require longer treatment to achieve a desired amount of iron salts in solution. Thus, the duration of treatment may be at least 1, 2, 3, 4, 5, 6, 7, 8, or 10 hours and / or not more than 2, 3, 4, 5, 6, 7, 8, 10, 12, 15, 20, 24, 30, 36, 40, 48, 60, or 72 hours. In certain embodiments, the duration can be 2-24 hours, such as 4-18 hours or even 4-12 hours or less. In certain embodiments, the duration may be 6-72 hours, such as 4-48 hours, or 4-36 hours, or 4-24 hours.

[0093] The pulp can be agitated during treatment, e.g., stirred, for example stirred at 10- 1000 RPM, 20-800 RPM, 50-500 RPM, 50-400 RPM, or 100-300 RPM. In preferred embodiments, the pulp is stirred at 50-400 RPM, more preferably at 100-300 RPM. Other methods of agitation as known in the art may be used. An iron-depleted solid fraction and an iron-rich liquid fraction are produced from the pulp. Some of the acid, e.g., H2SO4, may move into gas or vapor phase during the process, and can be recaptured and returned for use as leaching agent.

[0094] In some variations, adding a first acid may comprise adding an organic or biogenic acid (e.g., oxalic acid). Adding an organic first acid may selectively leach the iron-rich solid fraction, thereby enabling selective extraction of metals. Examples of organic acids that may be incorporated include: Propionic acid, Butyric acid, Citric acid, Succinic acid, Malic acid,Tartaric acid, and Oxalic acid. In one example, the first organic acid may selectively leach all minerals from the iron-rich solid fraction (e.g., by thermal decomposition).

[0095] In some variations, microbes may be implemented to produce the first organic acid. Microbes may be engineered to produce organic acids by utilizing CO2 as a carbon source and therefore CO2 produced by decomposing the organic acid in subsequent steps may be recycled or mitigated by feeding this CO2 to the microbes.D2. Separating the Iron-rich Liquid Fraction from the Iron-poor Solid Fraction

[0096] The iron-rich liquid fraction is separated from the iron-poor solid fraction, thus separating the metals in the iron-rich liquid fraction from the iron-poor solid fraction. Depending on the chemical composition of the iron-rich solid fraction, and hence the resulting iron-poor solid fraction, the iron-poor solid fraction may be used as supplementary cementitious materials. Any suitable method of separation may be implemented. In some variations may further include washing, rinsing, and / or drying the iron-poor solid fraction.

[0097] In some variations, separating the iron-rich liquid fraction from the iron-poor solid fraction is accomplished by filtration. In one implementation, vacuum filtration is used, wherein a pressure difference is used to flow fluid through a filter. In another implementation, hot filtration is used, wherein the solution is heated and then forced through a filter. In another implementation cold filtration is used, wherein the solution is initially cooled down to crystallize additional components (e.g., SCM), and then filtered. In some variations, a filtration press is implemented for separating the solid fraction. The filter press may enable stacking of multiple filter elements and allow the filter to be easily opened to remove the filtered solids. A filter press may be implemented with any desired filtering process as described above.

[0098] Separating the iron-depleted solid fraction from the iron-rich liquid fraction may significantly deplete the volume of the iron-rich liquid fraction. Therefore, either before this happens or once this occurs, additional solution may be added to the iron-rich fraction to replenish the volume. This may occur at any separation and / or precipitation step. Additional solution may be added at any step to maintain a desired working volume. The filtrate (iron- poor solid fraction) may be washed to recover any remaining iron-rich liquid fraction, or any iron compounds that have precipitated from the iron-rich liquid fraction during processing. The number of washes and the amount of solvent used per wash can be determined based on thedesired concentration of the iron-rich liquid fraction, the desired iron recovery, or any other factors apparent to one of the art.D3. Optionally Treating the Iron-Rich Liquid Fraction

[0099] It may be useful or necessary to optionally treat the iron-rich liquid fraction to precipitate or otherwise remove any metal salts as solid metal compounds prior to isolating the iron from the iron-rich liquid fraction. This may be advantageous when such a reaction may be performed at desired temperature or concentration that is different than the temperature or concentration used to isolate the iron compound, and particularly advantageous when isolating the iron compound is performed at more dilute concentrations than leaching. In some embodiments, the solid metal compounds include metal oxides, hydroxides, or oxyhydroxides, sulfates, chlorides, carbonates, or combinations thereof.

[0100] For example, the iron-rich liquid fraction may contain additional compounds, including one or more of magnesium compounds, aluminum compounds, and sodium compounds. Treatment may be used to isolate these compounds, transform them into useful compounds, regenerate a leaching agent, or any combination thereof. A thermal, chemical, electrical, or electrochemical process may be implemented in regenerating the leaching agents.

[0101] In one embodiment, the magnesium compounds and / or iron aluminum can be removed by precipitation and / or recrystallization. Precipitation or (re)crystallization may be induced varying reaction conditions, such as the temperature, by heating or cooling to reduce solubility, or by removing water to adjust concentration, or adding one or more additional reagents to induce precipitation through, for example, the common ion effect. In some embodiments, a seeded (re)crystallization is used. In some embodiments, additional reagents are used to induce precipitation through the common ion effect.

[0102] When multiple salts are present, they may be selectively precipitated or (re)crysta II ized according to their solubility. As an example, when aluminum sulfate and magnesium sulfate are present, the aluminum sulfate may be precipitated or (re)crysta llized first and removed, by cooling the solution, then magnesium sulfate, or hydrates thereof may be precipitated or (re)crystallized from the iron-rich fraction by removal of water.

[0103] In some embodiments, regenerating the leaching agents and / or base may take place through thermal decomposition. As an example, when one or more of magnesium compounds, aluminum compounds, and sodium compounds are present in the iron-rich liquidfraction, these substances may be collected individually or together, then undergo thermal decomposition to either regenerate the leaching agent, or alternatively, produce a compound that undergoes further treatment to regenerate the leaching agent. As an example, when the leaching agent is H2SO4, the iron-rich liquid fraction may comprise one or more of magnesium sulfate (MgSO4), aluminum sulfate (AI2(SO4)3), and sodium sulfate (Na2SO4). One or more of these compounds may undergo thermal decomposition to yield the corresponding metal oxide and produce SO2. The SO2 produced may undergo further treatment, either electrochemically or via the contact process, to regenerate H2SO4.

[0104] In one preferred embodiment, an aluminum sulfate salt is precipitated, and used for the production of metallic aluminum from an aluminum sulfate molten salt. The iron-rich and aluminum-depleted liquid fraction is then treated to precipitate magnesium sulfate, which undergoes thermal decomposition to yield magnesium oxide (MgO). The magnesium oxide may be used as is, or slaked to produce magnesium hydroxide may be used for carbon dioxide mineralization, either via direct air capture or carbon capture, utilization, and storage (CCUS).D4. Isolating an Iron from the Iron-Rich Liquid Fraction

[0105] Isolating iron from the iron-rich fraction functions to separate the iron from the iron-rich liquid fraction, preferably in the form of metallic iron. Generally, this is accomplished by adding a reducing agent, and optionally an oxidizing agent, or by electrolysis, electrodeposition, and / or electrowinning. In a preferred embodiment, isolating iron from the iron-rich liquid fraction uses electrodeposition and / or electrowinning.

[0106] In some embodiments, isolating the iron may be performed prior to separating the solid iron-depleted fraction from the iron-rich liquid fraction. As an example, the iron-rich liquid fraction, as yet separated from the iron-depleted solid fraction, may undergo addition of a reducing agent, and / or electrolysis, electrodeposition, and / or electrowinning to isolate iron. Electrodeposition and / or electrowinning may be performed in a batch process, or in a continuous process, e.g. using a flow reactor, as is known in the art.

[0107] In electrodeposition and / or electrowinning, iron, present as an ion or as a compound in the iron-rich fraction, may be reduced to metallic iron and be isolated, while another substance may be oxidized. The substance that is oxidized may comprise water, or alternatively may comprise a substance specific to the leaching agent (e.g. chloride ions whenHCI is used as the leaching agent). The substance that is oxidized may be multiple substances, especially in the case where competing oxidation reactions occur at the cathode.

[0108] In a specific embodiment, electrodeposition, and / or electrowinning comprises the following half reactions:H2O ->1 / 2O2+ 2H++ 2 e-

[0109] In other embodiments, the substance that is oxidized may be formed electrochemically in another process. As an example, if H2 is produced at any part of the process, or in another process, H2 may, in turn, be oxidized to form protons, while iron salts are reduced to metallic iron, i.e. a hydrogen depolarized anode is used for electrodeposition or electrowinning, as is known in the art. Alternatively, if SO2 is produced at any part of the process, or in another process, SO2 may be oxidized to produce SO3 and / or H2SO4, i.e. one electrode is a SO2 depolarized electrode. Alternatively, the two processes can be combined, where SO2 is electrochemically oxidized and water is electrochemically reduced to produce H2 and H2SO4, H2 is oxidized to form protons, while iron salts are reduced to metallic iron, i.e. a hydrogen depolarized anode is used for electrodeposition or electrowinning. The depolarized anode is not limited to the above, and one of ordinary skill in the art will appreciate that different depolarized anodes may be employed. Some example reactions are shown below:Fe2++ 2e" -> Fe°H2- 2H++ 2 e"SO2+ 2 H2O -> H2SO4 + 2 H++ 2 e-SO2+ H2O -> H2SO4 + H2

[0110] In some embodiments, electrodeposition and / or electrowinning is performed in an undivided setup, i.e. without a membrane. In other embodiments, a membrane may be used. The type of membrane may be an anion selective membrane or a cation selective membrane. In a preferred embodiment, the membrane is an anion selective membrane. When an anion selective membrane is used, it may be possible to allow the anions (e.g. sulfate ions when H2SO4 is used as the leaching agent) to cross the anion selective membrane, while protons and iron are prevented, or limited, from crossing the anion selective membrane. Thiscan prevent or limit the occurrence of the hydrogen evolution reaction (HER), and also prevent or limit the oxidation of Fe2+ to Fe3+, both of which limits the electrochemical (Faradaic) efficiency. In some embodiments, one or more additives may be used to buffer the pH and / or stabilize the electrodeposited iron; the precise nature and concentration of the additives may be apparent to those in the art. The temperature may be controlled to optimize the efficiency and / or rate of electrodeposition, or to obtain a desired balance between the same.

[0111] During the electrodeposition and / or electrowinning of iron, protons may be produced at the anode through the oxidation of water or the use of a H2- or SO2-depolarized anode. Since the iron will typically be in the form of the salt of the leaching agent, e.g. iron sulfate when the leaching agent is H2SO4, when iron is reduced at the cathode, and protons are produced at the anode, the leaching agent may be regenerated.

[0112] The iron may be further treated to produce, e.g. steel, using methods known in the art.

[0113] After isolating the iron, an iron-depleted liquid fraction may remain. The iron- depleted liquid fraction may be further treated depending on the composition of the iron- depleted liquid fraction.D5. Optionally Further Treating the Iron-Depleted Liquid Fraction

[0114] The iron-depleted liquid fraction may contain additional compounds, including one or more of magnesium compounds, aluminum compounds, and sodium compounds. Further treatment may be used to isolate these compounds, transform them into useful compounds, regenerate a leaching agent, or any combination thereof.

[0115] In one embodiment, the magnesium compounds and / or iron aluminum can be removed by precipitation and / or recrystallization. Precipitation or (re)crystallization may be induced varying reaction conditions, such as the temperature, by heating or cooling to reduce solubility, or by removing water to adjust concentration, or adding one or more additional reagents to induce precipitation through, for example, the common ion effect. In some embodiments, a seeded (re)crystallization is used. In some embodiments, additional reagents are used to induce precipitation through the common ion effect.

[0116] When multiple salts are present, they may be selectively precipitated or (re)crysta II ized according to their solubility. As an example, when aluminum sulfate and magnesium sulfate are present, the aluminum sulfate may be precipitated or (re)crysta llizedfirst and removed, by cooling the solution, then magnesium sulfate, or hydrates thereof may be precipitated or (re)crystallized from the remaining iron-depleted fraction by removal of water.

[0117] The treatment may serve to regenerate the leaching agents implemented in breakdown and subsequent purification of the starting material. A thermal, chemical, electrical, or electrochemical process may be implemented in regenerating the leaching agents.

[0118] In some embodiments, regenerating the leaching agents and / or base may take place through thermal decomposition. As an example, when one or more of magnesium compounds, aluminum compounds, and sodium compounds are present in the iron-depleted liquid fraction after isolation of the iron, these substances may be collected individually or together, then undergo thermal decomposition to either regenerate the leaching agent, or alternatively, produce a compound that undergoes further treatment to regenerate the leaching agent. As an example, when the leaching agent is H2SO4, the iron-depleted fraction may comprise one or more of magnesium sulfate (MgSO4), aluminum sulfate (AI2(SO4)3), and sodium sulfate (Na2SO4). One or more of these compounds may undergo thermal decomposition to yield the corresponding metal oxide, and produce SO2. SO2 may undergo further treatment, either electrochemically or via the contact process, to regenerate H2SO4.

[0119] In one preferred embodiment, an aluminum sulfate salt is precipitated, and used for the production of metallic aluminum from an aluminum sulfate molten salt. The iron- depleted and aluminum-depleted liquid fraction is then treated to precipitate magnesium sulfate, which undergoes thermal decomposition to yield magnesium oxide (MgO). The magnesium oxide may be used as is, or slaked to produce magnesium hydroxide may be used for carbon dioxide mineralization, either via direct air capture or carbon capture, utilization, and storage (CCUS).Exemplary Embodiments

[0120] Fig. 10 shows one exemplary embodiment wherein the leaching agent is H2SO4, and the iron-rich solid fraction comprises magnesium and aluminum, but first and second iron- rich fractions are either not present or are not separated. In this embodiment, treating the iron-rich solid fractions comprises: a. creating an iron-rich liquid fraction and an iron-poor solid fraction from the iron- rich solid fraction;i. separating the iron-rich liquid fraction from the iron-poor solid fraction; and ii. isolating iron from the iron-rich liquid fraction to produce an iron- depleted liquid fraction and iron; iii. separating an aluminum compound from the iron-depleted liquid fraction; and iv. separating a magnesium compound from the iron-depleted liquid fraction.

[0121] Fig. 11 shows one exemplary embodiment wherein the leaching agent is H2SO4, where the iron-rich solid fraction is further treated to separate first and second iron-rich fractions. In such a variation, treating the iron-rich solid fraction comprises: a. creating an iron-rich liquid fraction and an iron-poor solid fraction from the second iron-rich fraction; i. separating the iron-rich liquid fraction from the iron-poor solid fraction and first iron-rich fraction;A. separating the iron-poor solid fraction from the first iron-rich fraction; ii. isolating iron from the iron-rich liquid fraction to produce an iron- depleted liquid fraction and iron; iii. separating an aluminum compound from the iron-depleted liquid fraction; and iv. separating a magnesium compound from the iron-depleted liquid fraction.Conclusion

[0122] Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.

[0123] All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains. References cited hereinare incorporated by reference herein in their entirety to indicate the state of the art as of their publication or filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art. For example, when composition of matter are claimed, it should be understood that compounds known and available in the art prior to Applicant's invention, including compounds for which an enabling disclosure is provided in the references cited herein, are not intended to be included in the composition of matter claims herein.

[0124] As used herein, "comprising" is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, "consisting of" excludes any element, step, or ingredient not specified in the claim element. As used herein, "consisting essentially of" does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms "comprising", "consisting essentially of" and "consisting of" may be replaced with either of the other two terms. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

[0125] One of ordinary skill in the art will appreciate that starting materials, biological materials, reagents, synthetic methods, purification methods, analytical methods, assay methods, and biological methods other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

Claims

CLAIMS1. A method for co-production of a cement material and iron, comprising: providing a non-carbonate material comprising calcium and iron; beneficiating the non-carbonate material to provide a calcium-rich solid fraction and an iron-rich solid fraction; creating a calcium-rich liquid fraction and calcium-poor solid fraction from the calcium- rich solid fraction; separating the calcium-rich liquid fraction from the calcium-poor solid fraction; precipitating a solid calcium compound from the calcium-rich liquid fraction to provide a calcium-depleted liquid fraction; treating the solid calcium compound to produce a cement material; creating an iron-rich liquid fraction and an iron-poor solid fraction from the iron-rich solid fraction; separating the iron-rich liquid fraction from the iron-poor solid fraction; and isolating iron from the iron-rich liquid fraction to produce an iron-depleted liquid fraction and iron.,2. The method of claim 1, further comprising treating the calcium-depleted liquid fraction to precipitate one or more solid metal compounds from one or more metal salts.

3. The method of claim 2, wherein the one or more solid metal compounds comprises a solid aluminum compound.

4. The method of claim 3, wherein the solid aluminum compound comprises aluminum chloride hexahydrate.

5. The method of claim 1, further comprising: treating the calcium-rich liquid fraction prior to precipitating a solid calcium compound to precipitate a solid metal compound from one or more metal salts prior to precipitating a solid calcium compound from the calcium-rich liquid fraction to provide a calcium-depleted liquid fraction.

6. The method of claim 5, wherein the solid metal compound comprises one or more of a solid iron, a solid aluminum compound, and a solid magnesium compound.

7. The method of claim 5, wherein the solid metal compound comprises one or more of a metal oxide, metal hydroxide, metal oxyhydroxide, metal sulfate, metal chloride, or metal carbonate.

8. The method of claim 1, further comprising treating the iron-depleted liquid fraction to precipitate one or more solid metal compounds from one or more metal salts.

9. The method of claim 8, wherein the one or more solid metal compounds comprises one or more of a solid aluminum compound and a solid magnesium compound.

10. The method of claim 9, wherein the solid aluminum compound comprises aluminum sulfate or a hydrate thereof, and the solid magnesium compound comprises magnesium sulfate or a hydrate thereof.

11. The method of claim 1, further comprising: treating the iron-rich liquid fraction prior to isolating iron to precipitate a solid metal compound from one or more metal salts prior to precipitating a solid calcium compound from the calcium-rich liquid fraction to provide a calcium-depleted liquid fraction.

12. The method of claim 11, wherein the solid metal compound comprises one or more of a solid a solid aluminum compound and a solid magnesium compound.

13. The method of claim 12, wherein the solid aluminum compound comprises aluminum sulfate or a hydrate thereof, and the solid magnesium compound comprises magnesium sulfate or a hydrate thereof.

14. The method of claim 1, wherein the solid calcium compound comprises calcium hydroxide or calcium carbonate.

15. The method of claim 1, wherein the solid calcium compound comprises calcium sulfate or a hydrate thereof.

16. The method of claim 1, wherein the cement material comprises calcium hydroxide or calcium oxide.

17. The method of claim 1, wherein the cement material comprises calcium sulfoaluminate cement.

18. The method of claim 1, wherein the cement material comprises portland cement.

19. The method of claim 1, further comprising pre-treating the iron-rich solid fraction prior to remove one or more of a calcium compound and a magnesium compound.

20. The method of claim 19, wherein the calcium compound comprises calcium carbonate, and the magnesium compound comprises magnesium carbonate.

21. The method of claim 19, wherein pre-treating comprise a hydrothermal carbonation step.

22. The method of claim 21, wherein the pre-treating further comprises separating one or more of aqueous calcium carbonate and aqueous magnesium carbonate from the pre-treated iron-rich fraction.

23. The method of claim 22, wherein the pre-treating further comprises separating one or more of solid calcium carbonate and solid magnesium carbonate from the pre-treated iron-rich fraction.

24. The method of claim 1, wherein the iron-rich solid fraction comprises first and second iron-rich solid fractions.

25. The method of claim 24, further comprising separating the first and second iron-rich fractions.

26. The method of claim 25, wherein separating the first and second iron-rich fractions occurs prior to creating an iron-rich liquid fraction and an iron-poor solid fraction from the iron- rich solid fraction.

27. The method of claim 25, wherein separating the first and second iron-rich fractions occurs after creating an iron-rich liquid fraction and an iron-poor solid fraction from the iron- rich solid fraction.

28. The method of claim 27, wherein separating the iron-rich liquid fraction from the iron- poor solid fraction also comprises separating the iron-rich liquid fraction from the first iron-rich fraction.

29. The method of claim 28, further comprising separating the iron-poor solid fraction from the first iron-rich fraction.

30. The method of claim 24, wherein the first iron-rich solid fraction comprises pyroxene, and the second iron-rich solid fraction comprises olivine.

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