Compositions, methods of production, and uses in carbon dioxide (CO2) sequestration

Abstract

Described herein are compositions, methods of producing the compositions, and uses of the compositions for carbon dioxide sequestration. The compositions include a mixture of magnesium hydroxide, a metal hydroxide, and water to create a composition that is highly effective at sequestering carbon dioxide.

Description

[Technical Field]

[0001] Described herein are compositions, methods of producing the compositions, and uses of the compositions for carbon dioxide (CO2) sequestration. [Background technology]

[0002] Carbon dioxide (CO2) emissions are a major contributor to climate change, and there is growing interest in ways to minimize or avoid their emissions. One way to reduce CO2 emissions is to sequester or capture CO2 before it enters the atmosphere.

[0003] Soda lime is a compound that has been used not only to sequester CO2 from industrial systems, but also to maintain breathable air in enclosed spaces.

[0004] Soda lime is effective at removing CO2 from low to high concentrations.

[0005] Soda lime is not practical for large-scale carbon sequestration as a means of reducing global CO2 levels. While existing sequestration agents such as soda lime are capable of sequestrating CO2, the process of producing soda lime from calcium carbonate releases CO2. Therefore, there is no benefit to using soda lime as a net-zero or net-negative CO2 sequestration agent. The reason for the reduction in CO2 during production, as described above, is that the source of the material from which soda lime is obtained is typically carbonate minerals, which release CO2 during soda lime production. Furthermore, converting carbonates to soda lime requires significant energy, which can also contribute to CO2 emissions via fossil fuel combustion.

[0006] There is some prior art that considers carbon sequestration.

[0007] US2013 / 0280152 by Singh describes a method and apparatus for removing carbon dioxide from a gas stream using an alkaline absorption solution, in which Singh teaches mixing water with one or more alkaline components selected from the group consisting of sodium hydroxide, calcium hydroxide, magnesium hydroxide, and potassium hydroxide. However, Singh does not discuss the combination of a magnesium hydroxide material with water and a metal hydroxide, nor does he discuss the catalytic effect of the metal hydroxide in this combination on carbon sequestration. Furthermore, Singh merely mentions magnesium hydroxide as one of several alkaline reagents, and no examples using magnesium hydroxide are provided by Singh.

[0008] WO 2022 / 113025 by Dreisinger describes a method by which a continuous process of hydrometallurgical value extraction can be carried out using the products of a carbon capture and a reagent-generating electrolytic process, which respectively produces an acid leachate and an alkali hydroxide, which can then be used directly as a precipitant in a hydrometallurgical process, or converted by carbon capture to an alkali metal carbonate, which can then be used as a precipitant in a selective hydrometallurgical process.

[0009] Dreisinger does not discuss acid washes or post-sodium hydroxide addition, and no magnesium salt solution is produced at any stage. A base wash is performed after multiple washes using sodium carbonate, with a final base wash producing magnesium hydroxide. Furthermore, Dreisinger's process produces more carbon dioxide due to the carbon dioxide produced during production, which is the opposite of what is desired from a sequestration agent, since the net effect would be a balance between carbon production and sequestration or a net carbon reduction.

[0010] Ideally, CO2 sequestrants should be sourced from non-carbonate materials and / or have a production process that does not release CO2, so as to result in net CO2 sequestration.

[0011] Further aspects and advantages of the compositions, methods of production, and methods of CO2 sequestration will become apparent from the ensuing description, which is given by way of example only. Summary of the Invention

[0012] Described herein are compositions, methods of producing the compositions, and uses of the compositions for carbon dioxide sequestration. The compositions can include a mixture of magnesium hydroxide, water, and a metal hydroxide to form a composition that can be highly effective at sequestering carbon dioxide. Furthermore, the compositions can be produced in a variety of ways that do not release CO2 during production.

[0013] In a first aspect, Magnesium hydroxide material, water, and metal hydroxide Including, Metal hydroxide is not magnesium hydroxide, A composition is provided.

[0014] In a second aspect, there is provided a composition configured to be exposed to CO2 and react with CO2 to form stable magnesium carbonate and hydrated magnesium carbonate, thus sequestering CO2, comprising: CO2 sequestration magnesium hydroxide material, water, and Catalytic concentrations of metal hydroxides Including, The metal hydroxide is an alkali metal but is not magnesium hydroxide; A composition is provided.

[0015] In a third aspect, selecting said magnesium hydroxide material; selecting said metal hydroxide; and mixing said water with a magnesium hydroxide-containing material and a metal hydroxide to form a composition; There is provided a method of producing a composition substantially as described above, comprising:

[0016] In a fourth aspect, selecting a source of magnesium-containing silicate; subjecting the selected magnesium-containing silicate source to an acid wash to produce an acid digestion solution; subjecting the acid digested solution to a base wash by adding a base solution to the acid digested solution to produce a magnesium salt solution, and during this process removing silica, iron, or other metals and minerals from the magnesium salt solution; subjecting the magnesium salt solution to electrolysis to recover magnesium hydroxide material; mixing the recovered magnesium hydroxide material with said water and said metal hydroxide containing solution to form a composition. Including, There is provided a method for producing a composition substantially as described above.

[0017] In a fifth aspect, selecting a source of magnesium-containing silicate; subjecting the selected magnesium-containing silicate source to an acid wash to produce an acid digestion solution; subjecting the acid decomposition liquid to a base wash by adding a base solution to the acid decomposition liquid to produce a magnesium salt solution, and during this process removing silica, iron, or other metals and minerals from the magnesium salt solution; performing a further base wash of the magnesium salt solution to produce a magnesium hydroxide material in solution, and filtering the magnesium hydroxide material in solution to recover the magnesium hydroxide material and the separated metal salt solution; and mixing the recovered magnesium hydroxide material with said water and said metal hydroxide containing solution to form a composition. Including, There is provided a method for producing a composition substantially as described above.

[0018] In a sixth aspect, selecting a source of magnesium-containing silicate; subjecting the selected magnesium-containing silicate source to a base wash by adding a base solution to the magnesium-containing silicate source to produce a magnesium hydroxide material solution; and mixing the resulting magnesium hydroxide material solution with the water and the metal hydroxide-containing solution to form a composition. Including, There is provided a method for producing a composition substantially as described above.

[0019] In a seventh aspect, selecting a composition substantially as described above; Exposing the composition to CO2 A method for sequestrating CO2 by the composition reacts with CO to form stable magnesium carbonate and hydrated magnesium carbonate, thus sequestering CO; A method for sequestrating CO2 is provided.

[0020] The inventors have identified compositions that work synergistically to sequester CO2. Magnesium hydroxide materials do sequester CO2. The inventors have found that by mixing metal hydroxides and water with magnesium hydroxide, the rate of CO2 sequestration by magnesium hydroxide can be rapidly accelerated or catalyzed to the point where it becomes a rapid and useful method for reducing CO2 emissions. Sequestration can be by direct air capture or from a point source.

[0021] A further advantage identified is that the compositions can be made without using processes that themselves produce CO2, thereby negating any benefit of subsequent sequestration.

[0022] Further aspects of the compositions, methods of production, and methods of CO2 sequestration will become apparent from the following description, given by way of example only, and with reference to the accompanying drawings. [Brief explanation of the drawings]

[0023] [Figure 1] 1 shows a flow diagram of a method for producing magnesium hydroxide in conjunction with the production of subsequent compositions. [Figure 2] 1 shows a flow diagram of an alternative method for producing magnesium hydroxide materials in conjunction with the production of subsequent compositions. [Figure 3] 1 shows a flow diagram of a further alternative method for producing magnesium hydroxide materials in conjunction with the production of subsequent compositions. [Figure 4] 1 shows a flow diagram in which a solid composition is used to sequester CO2 by passing air over the composition material, and in which the solid composition is in pelletized form and reacts with carbon dioxide gas in the air to produce a hydrated magnesium carbonate end product. [Figure 5] 5 shows an apparatus for direct air capture according to the flow diagram of FIG. [Figure 6] 1 shows a flow diagram of an alternative sequestration method using a slurry of the composition in a wet scrubber configuration where the slurry is dispersed as a fine mist within a column of hot gas. [Figure 7] 1 shows a further flow diagram of a method of isolation via bubbling CO through a slurry containing the composition. [Figure 8] 1 shows a graph illustrating the results of a CO2 sequestration test. [Figure 9] 1 shows XRD graph results showing the results of a CO2 sequestration test. [Figure 10] A study testing the catalytic effect of metal hydroxides on CO2 sequestration by magnesium hydroxide is presented. DETAILED DESCRIPTION OF THE INVENTION

[0024] As noted above, compositions for carbon dioxide sequestration, methods of producing the compositions, and uses of the compositions are described. The compositions may include a mixture of magnesium hydroxide material, water, and a metal hydroxide to form a composition that may be highly effective in sequestering carbon dioxide.

[0025] For purposes of this specification, the terms "about" or "approximately" and grammatical variations thereof mean a quantity, level, degree, value, number, frequency, percentage, dimension, size, amount, weight, or length that varies by up to about 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% of a reference quantity, level, degree, value, number, frequency, percentage, dimension, size, amount, weight, or length.

[0026] The term "substantially" or grammatical variations thereof refers to at least about 50%, for example, 75%, 85%, 95%, or 98%.

[0027] The term "comprise" and its grammatical variations shall be understood to have an inclusive meaning, i.e., to mean encompassing not only the recited components to which it directly refers, but also other unspecified components or elements.

[0028] As used herein, the term "alkali metal" and grammatical variations thereof refer to both alkali and alkaline metals.

[0029] As used herein, the term "hydrate" and grammatical variations thereof refer to a compound, composition, or substance that has a variable amount of water present.

[0030] composition In a first aspect, Magnesium hydroxide material, water, and metal hydroxide Including, Metal hydroxide is not magnesium hydroxide, A composition is provided.

[0031] In a second aspect, there is provided a composition configured to be exposed to CO2 and react with CO2 to form stable magnesium carbonate and hydrated magnesium carbonate, thus sequestering CO2, comprising: CO2 sequestration magnesium hydroxide material, water, and Catalytic concentrations of metal hydroxides Including, The metal hydroxide is an alkali metal but is not magnesium hydroxide; A composition is provided.

[0032] The inventors have determined that the above compositions work synergistically to sequester CO2. Magnesium hydroxide materials do sequester CO2, but they do so slowly and not at commercially useful kinetics. The inventors have found that by mixing metal hydroxide and water with the magnesium hydroxide material, the rate of CO2 sequestration by magnesium hydroxide can be rapidly accelerated to the point where it becomes a rapid and useful method for reducing CO2 emissions. Sequestration can be by direct air capture or from a point source.

[0033] Magnesium hydroxide material The magnesium hydroxide material may exist as Mg(OH)2. The magnesium hydroxide material may exist as a magnesium hydroxide hydrate.

[0034] The magnesium hydroxide material may be derived from magnesium silicate-containing minerals.

[0035] The magnesium hydroxide material may be derived from olivine, serpentine group minerals, pyroxene, amphibole, and combinations thereof.

[0036] Magnesium hydroxide materials may be obtained from minerals such as olivine, a magnesium-rich silicate that occurs in widespread mafic and ultramafic rock deposits. For these reasons, olivine may be an ideal source material for producing the magnesium hydroxide used to form the compositions.

[0037] Magnesium silicate-containing minerals can be sourced as sand, sediment, rock, and combinations thereof. These sources are common natural forms of magnesium silicate-containing materials.

[0038] The composition may contain approximately 1-99 wt.%, or 5-95 wt.%, or 20-90 wt.%, or 60-90 wt.%, or approximately 70-80 wt.% magnesium hydroxide material. These ranges may provide improved efficiency of action, which may be based on the relative proportions of magnesium hydroxide material, water, and metal hydroxide.

[0039] water Water may be used to enable the reaction of CO2 with the magnesium hydroxide material and metal hydroxides present for carbon sequestration purposes. For example, the metal hydroxide may act as a catalyst to accelerate, or shift, or both accelerate and shift the reaction equilibrium between the magnesium hydroxide material and carbon dioxide in favor of carbonation of the magnesium hydroxide Mg(OH)2 material. Water may be used to aid the reaction by enabling intimate mixing of the compounds used.

[0040] The composition may comprise at least approximately 1-99% by weight, or 5-99% by weight, or 5-95% by weight, or 5-60% by weight, or 5-35% by weight, or approximately 20% by weight of water. In one example, the composition may be greater than approximately 5% by weight water. Water may be required to promote CO2 uptake by the magnesium hydroxide material. The amount of water may be varied to alter the activity and reactivity required for the end-user application and product.

[0041] The amount of water present in the composition may depend on the final form of the composition.

[0042] metal hydroxide The metal hydroxide may be an alkali metal.

[0043] The metal hydroxide may not be magnesium hydroxide.

[0044] The metal hydroxide may be selected from sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)), and combinations thereof. In one embodiment, the metal hydroxide is sodium hydroxide (NaOH) alone. Sodium hydroxide may be advantageous given how widely available and low cost this metal hydroxide is, although as stated, other metal hydroxides such as those listed may be used.

[0045] As noted above, the presence of a metal hydroxide is believed to catalyze the reaction of the magnesium hydroxide material with CO, resulting in significantly more CO sequestration than the magnesium hydroxide material alone. The listed metal hydroxides are abundant and relatively inexpensive, which is why they may be advantageous. Other metal hydroxides may also be used, and this list should not be construed as limiting.

[0046] The composition may contain approximately 1-20 wt. %, or 1-10 wt. %, or 2-10 wt. %, or 3-10 wt. %, or 4-10 wt. %, or 5-10 wt. %, or approximately 5-8 wt. These ranges can improve the efficiency of operation, which can be based on the relative ratios of magnesium hydroxide material, metal hydroxide, and water. The efficiency of operation can be tailored to meet the chemical reactivity (i.e., CO2 reactivity and sequestration) requirements of the end-use application. Below 1 wt. % of the metal hydroxide, the catalytic effect appears to be absent, or at least not to any significant extent. From 1 to 10%, the reactivity of magnesium hydroxide in CO2 sequestration steadily increases. Above 10%, the catalytic effect plateaus, and as the amount of magnesium hydroxide becomes diluted, sequestration decreases and the magnesium hydroxide no longer sequester CO2 at a useful rate. Maximizing the magnesium hydroxide content is optimal with respect to providing the primary reagent for sequestration, and although the degree of catalytic activity plateaus between 10% and 20%, up to 20% by weight the metal hydroxide still appears to catalyze the reaction. To minimize processing costs and materials, it may be useful to minimize the metal hydroxide content, and therefore an amount of 1-10% may be optimal.

[0047] pellet or granule form The composition may be configured as pellets or granules, which may be useful for ease of handling.

[0048] The pellets or granules contain approximately (by weight): 1-99%, or 5-95%, or 20-90%, or 60-90%, or 70-80%, or approximately 75% magnesium hydroxide material; 1 to 99%, or 5 to 95%, or 5 to 60%, or 5 to 35%, or approximately 20% water, and 0.1 to 99%, or 1 to 95%, or 0.1 to 20%, or 1 to 20%, or 1 to 10%, or 2 to 10%, or 3 to 10%, or 4 to 10%, or 5 to 10%, or approximately 5 to 8% metal hydroxide may include:

[0049] Relative proportions within the above ranges may be used as described elsewhere herein.

[0050] The pellets or granules produced may be approximately 1 μm to 10 mm in diameter, or 0.5 to 2 mm, or approximately 1 mm. Note that the term "diameter" is used for brevity. The pellets or granules need not be round or spherical as is implied by the diameter, and the pellets or granules may take on a variety of shapes within the full range of sizes described.

[0051] Slurry Form The composition may be configured as a slurry.

[0052] Slurry formulations can be useful to reduce or prevent handling problems due to dust and inhalation.

[0053] The solids content of the slurry can vary. In one example, the solids content can be 1-50% by weight, or 1-40% by weight, or 1-30% by weight, or 1-20% by weight, or 5-15% by weight, or approximately 10% by weight. A liquid content in this range can be useful to allow the slurry to be fluidized for transport.

[0054] The slurry contained approximately (by weight): 1-99% magnesium hydroxide, 5-99% water, and 0.1 to 99%, or 1 to 95%, or 0.1 to 20%, or 1 to 20%, or 1 to 10%, or 2 to 10%, or 3 to 10%, or 4 to 10%, or 5 to 10%, or approximately 5 to 8% metal hydroxide may include:

[0055] Relative proportions within the above ranges may be used as described elsewhere herein.

[0056] Silica-containing materials The composition may further comprise a silica-containing material. In one embodiment, the silica-containing material, if used, may be added as a powder. The silica-containing material may comprise approximately less than 50% by weight of the composition, or less than 40% by weight, or less than 30% by weight, or less than 20% by weight, or less than 10% by weight.

[0057] The silica-containing material may be clay, quartz, or other siliceous minerals.

[0058] The silica-containing material can be kaolin, smectite, bentonite, or vermiculite.

[0059] The inventors understand that silica-containing materials increase the rate at which the above compositions can sequester CO. Without being bound by theory, the mechanism as to why silica-containing materials increase sequestration rates may be due to the fact that these materials allow the compositions to have increased porosity, increasing the pore reaction area and providing a greater surface area for contact and reaction between the magnesium hydroxide material and CO.

[0060] inert material The composition may further comprise an inert material. The inert material may include carbonates, silicates, oxides, sulfates, and combinations thereof. The inert material may be selected from clay minerals, quartz, zeolites, calcite, magnetite, magnesite, and combinations thereof.

[0061] The inert materials used may be selected based on their ability to increase the overall porosity of the composition and improve the carbon sequestration rate of the composition. The inert materials used may also be selected based on their ability to meet specific physical properties for the final product.

[0062] The composition may include 5% by weight, or 10% by weight, or 15% by weight, or 20% by weight of inert material. The composition may include approximately 5-20% by weight, or 10-20% by weight, or 5-15% by weight, or 15-20% by weight of inert material. The amount of inert material present may be varied to allow for modification of porosity to meet the end-use requirements for the composition. The inventors have found that 5-20% by weight of inert material may be suitable for many CO2 sequestration applications.

[0063] metal salts The composition may further comprise a metal salt. The metal salt may be present in the composition as a residue from magnesium hydroxide material production. By way of example, various metal salts can be used to generate magnesium hydroxide materials, and at least some of these metal salts may remain in the magnesium hydroxide material used to form the composition.

[0064] The metal salt present in the composition may be selected from lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), magnesium chloride (MgCl), sodium sulfate (NaSO), magnesium sulfate (MgSO), calcium sulfate (CaSO), lithium sulfate (LiSO), calcium chloride (CaCl), and combinations thereof.

[0065] Metal salts, when present, may constitute approximately less than 20% by weight of the composition, or less than 19% by weight, or less than 18% by weight, or less than 17% by weight, or less than 16% by weight, or less than 15% by weight, or less than 14% by weight, or less than 13% by weight, or less than 12% by weight, or less than 11% by weight, or less than 10% by weight, or less than 9% by weight, or less than 8% by weight, or less than 7% by weight, or less than 6% by weight, or less than 5% by weight, or less than 4% by weight, or less than 3% by weight, or less than 2% by weight, or less than 1% by weight. In the inventor's experience, metal salt concentrations greater than 20% by weight may impair the effectiveness / ability of the composition to react with and sequester CO.

[0066] In the inventor's experience, metal salts, when present in low concentrations, have minimal, if any, effect on the activity of the composition with respect to CO2 reaction and sequestration.

[0067] Magnesium oxide The composition may further include magnesium oxide (MgO). Magnesium oxide may also be present as a residue from magnesium hydroxide material production. In the inventor's experience, MgO, when present, has minimal, if any, effect on the activity of the composition with respect to CO reaction and sequestration.

[0068] CO2 during production The composition is made from silicate minerals that do not have inherent CO2, like the carbonate groups found in materials used to form other sequestration materials, such as soda lime, so there can be little to no carbon emissions during production.

[0069] The composition may also react with carbon dioxide to capture and sequester it, as discussed further below.

[0070] Comparison with soda lime The compositions may have similar properties to soda lime and may therefore be used interchangeably with soda lime. "Similar properties" in this context refers to the ability of the compositions to preferentially and quickly sequester or reduce CO2, even at low concentrations. However, soda lime has the disadvantage that carbon dioxide is released from the soda lime production process. This means that subsequent sequestration merely results in a net neutralizing CO2 effect (i.e., the amount of CO2 sequestered is similar to the amount produced to produce the soda lime). In contrast, no CO2 is released during the production of the compositions described herein, and therefore, there may be a net benefit from the compositions reducing CO2 emissions to the atmosphere.

[0071] Production Method - Magnesium Hydroxide - Any Source In a third aspect, selecting said magnesium hydroxide material; selecting said metal hydroxide; and mixing said water with a magnesium hydroxide-containing material and a metal hydroxide to form a composition; There is provided a method of producing a composition substantially as described above, comprising:

[0072] Magnesium hydroxide material The magnesium hydroxide material may be generated via a processing method prior to carrying out the method or may be provided prior to the start of the method.

[0073] As mentioned above, the magnesium hydroxide material may exist as Mg(OH)2 or as a magnesium hydroxide hydrate.

[0074] Other aspects of the magnesium hydroxide, water, and metal hydroxides may be as described above and will not be repeated here for the sake of brevity.

[0075] Initial crushing Optionally, and where applicable, the magnesium hydroxide material may be crushed to an average particle size of less than 1 mm prior to the above process. Particle sizes less than 1 mm may be useful because they provide a higher surface area and therefore may enable higher reaction rates for CO2 sequestration. Additionally, production techniques for producing magnesium hydroxide material may proceed faster using mixtures with higher surface areas.

[0076] water removal Some water removal from the composition once formed may occur.

[0077] Water removal can be via drying. Drying can be via methods including filtration, conventional drying, and vacuum evaporation drying. Drying can be to reduce moisture content.

[0078] The water removal described above may result in approximately more than 5%, or more than 10%, or more than 20%, or more than 30%, or more than 40%, or more than 50%, or more than 60%, or more than 70%, or more than 80%, or more than 90% by weight of water being removed from the composition.

[0079] As noted elsewhere, sufficient water removal may be performed to produce a composition having a moisture content of at least about 1-99%, or 5-99%, or 5-95%, or 5-60%, or 5-35%, or about 20% water by weight.

[0080] Water removal to the extent described can be useful to reduce the energy requirements for drying materials where water is advantageous for reactivity, transportation, and minimization of dust / inhalation issues.

[0081] Pellets / Granules or Slurry The composition produced as described above may be formed into pellets or granules, or into a slurry. The pellets, granules, or slurry may have the characteristics previously described herein.

[0082] Other materials The resulting composition may be enriched with additional materials, including the silica-containing materials, inert materials, and metal salts described above.

[0083] Method of production - acid / base washing and magnesium salt electrolysis In a fourth aspect, selecting a source of magnesium-containing silicate; subjecting the selected magnesium-containing silicate source to an acid wash to produce an acid digestion solution; subjecting the acid decomposition liquid to a base wash by adding a base solution to the acid decomposition liquid to produce a magnesium salt solution, and during this process removing silica, iron, or other metals and minerals from the magnesium salt solution; subjecting the magnesium salt solution to electrolysis to recover a magnesium hydroxide material; and mixing the recovered magnesium hydroxide material with said water and said metal hydroxide containing solution to form a composition. Including, There is provided a method for producing a composition substantially as described above.

[0084] Magnesium-containing silicate source As noted elsewhere herein, magnesium-containing silicates may be obtained from magnesium silicate-containing minerals, including olivine, serpentine group minerals, pyroxene, and amphibole. Magnesium silicate-containing minerals may be sourced as sand, sediment, rock, and combinations thereof.

[0085] Crushing and grinding The magnesium-containing silicate may be crushed prior to the above treatment, which may be to sand size, i.e., an average diameter of less than approximately 1 mm.

[0086] The iron portion (if present) in the magnesium-containing silicate can be removed from the raw magnesium-containing silicate. Removal can be by magnetic separation or acid washing. Magnetic iron can be recovered as a by-product.

[0087] The remaining magnesium-containing silicate may be further pulverized to a particle size of less than 100 μm. The pulverized magnesium-containing silicate may be a finely pulverized magnesium-containing silicate before being treated in the above method.

[0088] Iron removal (if required) may also be accomplished using the finely divided magnesium-containing silicates described.

[0089] Two grinding steps may be performed. The number of grinding steps performed may vary depending on the size and type of resource material used. Two grinding steps may allow for easier iron removal followed by finer grinding to increase the reactivity and dissolution rate of the magnesium-containing silicate in the process.

[0090] It should be noted that although the terms "crushing" and "grinding" are used herein, this should not be construed as limiting, as this process relates to particle size reduction and surface area increase, which can be achieved by a variety of methods, not limited to the use of a crusher or grinder.

[0091] Acid washing Acid washing may be accomplished using an acid selected from, for example, hydrochloric acid (HCl) or sulfuric acid (H2SO4). These acids may be useful because of their ready availability and low cost. Other acids may be used, and reference to HCl or H2SO4 should not be construed as limiting.

[0092] The acid wash may be carried out at an elevated temperature, which may be approximately 40-95°C, or 50-90°C, or 60-85°C, or approximately 80°C. As the temperature increases, the effectiveness of the acid wash increases up to an optimum, which in the inventor's experience is around 80°C, although other temperatures may be used.

[0093] The acid wash can be carried out for a range of times. The acid wash can be carried out for approximately 1 to 24, or 1 to 12, or 1 to 6, or 1 to 5, or 1 to 4, or 1 to 3, or approximately 2 hours. The acid wash time can vary due to the variable mineralogy of the magnesium-bearing silicate resource material.

[0094] In the inventor's experience, the pH at the start of the acid wash can be less than pH 2, or even a negative pH. Over time, the pH can tend to increase as magnesium-containing silicates are decomposed by the acid conditions. In one example, if olivine is acid washed in 2 M HCl at 80° C. for 2 hours, after 2 hours the pH becomes positive (from below zero to approximately 0.5).

[0095] The acid wash may be followed by a further aging step, in which the pH is raised to above pH 1 for another 1 to 24 hours. This aging step may allow further silica formation before separation.

[0096] Base wash The base solution may be selected from lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg(OH)2), calcium hydroxide (Ca(OH)2). In the inventors' experience, other metal hydroxides may also be used. Sodium hydroxide (NaOH) was typically used by the inventors because it is readily available and has the lowest cost.

[0097] The base wash may be carried out at elevated temperatures. "Elevated temperatures" may be approximately 15-25°C above ambient conditions. Elevated temperatures may be approximately 40-95°C, or 40-80°C, or approximately 50-70°C. The base wash temperature may vary due to the variable mineralogical state of the magnesium-bearing silicate resource material. At elevated temperatures, many of the magnesium-bearing silicate minerals will react fully or to an optimal extent.

[0098] The base wash can be carried out for a range of times, such as from about 10 minutes to 12 hours, or from 10 minutes to 3 hours, or from 10 to 120 minutes, or from 10 to 90 minutes, or less than 90 minutes. The base wash time can vary due to the variable mineralogy of the magnesium-containing silicate resource material.

[0099] The base wash can be carried out in two steps. The first step can involve a first time span (less than approximately 60 minutes) of base wash, at the completion of which the pH rises to approximately 2 or greater. The second step can involve the addition of additional base solution and another time span of base wash, at the completion of which the pH can rise to approximately 4 or greater, to precipitate and remove silica and any precipitated iron. A two (or more) step base wash can be useful to allow for the separation of by-products from the reaction, which can be collected as a separate product stream. The time span of this second step can be approximately less than 24 hours, or less than 60 minutes, or less than 50 minutes, or less than 40 minutes, or less than 30 minutes, or less than 20 minutes, or less than 10 minutes.

[0100] electrolytic As can be appreciated, electrolyzer operating characteristics may vary depending on the details of the device operation. In one embodiment, the inventors have determined that the electrolyzer used is a mixed metal oxide titanium anode, stainless steel or nickel cathode, and operates at a current of at least about 0.1 kA / m at approximately 40-90°C. 2 It was found that a current density of 1000 .mu.m gave good separation.

[0101] Other materials may be used for the anode and cathode, and references to such materials are provided merely for illustrative purposes. Similarly, other temperatures and current densities may also be used.

[0102] water removal At least some water removal can be performed from the recovered magnesium hydroxide material in the process. Water removal can be performed prior to producing the composition. Water removal can be via drying. Drying can be via methods including air drying, filtration, conventional drying, vacuum evaporation, and combinations thereof.

[0103] Drying can also be used to reduce moisture in this embodiment. The water removal described above can result in the removal of approximately more than 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the water by weight from the composition. As noted elsewhere, sufficient water removal can be performed to produce a composition having a moisture content of at least approximately 1-99%, 5-99%, 5-95%, 5-60%, 5-35%, or approximately 20% water by weight.

[0104] Production method - mineral precipitation using metal hydroxide addition, metal salt electrolysis option In a fifth aspect, selecting a source of magnesium-containing silicate; subjecting the selected magnesium-containing silicate source to an acid wash to produce an acid digestion solution; subjecting the acid decomposition liquid to a base wash by adding a base solution to the acid decomposition liquid to produce a magnesium salt solution, and during this process removing silica, iron, or other metals and minerals from the magnesium salt solution; performing a further base wash of the magnesium salt solution to produce a magnesium hydroxide material in solution, and filtering the magnesium hydroxide material in solution to recover the magnesium hydroxide material and the separated metal salt solution; and mixing the recovered magnesium hydroxide material with said water and said metal hydroxide containing solution to form a composition. Including, There is provided a method for producing a composition substantially as described above.

[0105] Magnesium-containing silicate source As noted elsewhere herein, magnesium-containing silicates may be obtained from magnesium silicate-containing minerals, including olivine, serpentine group minerals, pyroxene, amphibole, and combinations thereof. Magnesium-containing silicates may be sourced as sand, sediment, rock, and combinations thereof.

[0106] Acid washing The acid wash described above can be accomplished in a similar manner as described above.

[0107] First Base Wash The first base wash described above can be performed in a manner similar to that described above. In one embodiment, the first base wash can be performed in one step or two steps. For example, the first base wash can include two base washes: first to remove silica and second to remove iron. Silica removal can be performed at a pH of about 2 or higher. Iron removal can be performed at a pH of about 4 or higher.

[0108] Alternatively, the first base wash may be performed in one step as one base wash that removes silica and iron together. In this example, the pH may be approximately 4 or greater.

[0109] Further base washes A further base wash may be used to precipitate and recover the magnesium hydroxide material, Mg(OH). This further base wash may be accomplished using NaOH or other metal hydroxides in one example.

[0110] Recovery may be by filtration, with the retentate in the filter containing the magnesium hydroxide material and the permeate from a further base wash being primarily a sodium salt solution (metal salt solution).

[0111] This additional base wash may raise the pH to approximately 10 or higher.

[0112] The further base wash may be maintained for a time period of at least about 10 minutes, or 1 hour, or up to about 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, or 24 hours (or possibly more) to ensure precipitation and generation of the magnesium hydroxide material.

[0113] Further base washes may be performed at temperatures of 20-90°C, or at temperatures of approximately 20, or 25, or 30, or 35, or 40, or 45, or 50, or 55, or 60, or 65, or 70, or 75, or 80°C.

[0114] electrolytic Electrolysis may be performed in the above process to recover the reagents. Electrolysis is not required to produce magnesium hydroxide via this method.

[0115] The separated metal salt solution may be subjected to electrolysis to produce an acid solution, a base solution, and optionally an evolved gas. The produced acid solution may be recovered for acid washing in the process, and the produced base solution may be recovered for base washing in the process.

[0116] For example, if hydrochloric acid is used for the acid wash and sodium hydroxide is used for the base wash, the metal salt may be a sodium salt in solution, the sodium salt solution consumed in the electrolytic cell, chlorine Cl (gas) recovered from the anode, and hydrogen H (gas) and sodium hydroxide (NaOH) recovered from the cathode. The H and Cl gases may be combined to form hydrochloric acid HCl, which may be recovered for use in the acid wash.

[0117] When sulfuric acid (HSO) (optionally containing NaHSO) is used for the acid cleaning process, hydrogen and NaOH may be evolved at the cathode and oxygen may be evolved at the anode during electrolysis of NaSO (produced from the reaction of MgSO with NaOH). Additionally, sulfuric acid (HSO) solution may also be evolved at the anode, which may also be recovered for use in further acid cleaning steps.

[0118] Other acid / base wash solutions may also be used in the above method, and electrolysis may be used to separate metal salts in the resulting solution into acid and base solutions.

[0119] The electrolytic cell may operate using operating characteristics similar to those of the electrolytic cell described above.

[0120] Cleaning The recovered magnesium hydroxide may be washed. Washing may be performed to remove impurities and increase the purity of the magnesium hydroxide material. The magnesium hydroxide material is typically washed with water using a countercurrent method to minimize water usage (i.e., using recovered water for the initial rinse and progressively cleaner water for the final rinse).

[0121] Other processes Other steps mentioned above, such as the use of base and acid solutions, slurry or pellet / granule formation, and other materials, may also be used in the present process, but will not be repeated here for the sake of brevity. By way of example, inert materials including carbonates, silicates, oxides, sulfates, and combinations thereof may be added as described further below. The inert materials may be selected from clay minerals, quartz, zeolites, calcite, magnetite, magnesite, and combinations thereof.

[0122] Production method - base washing In a sixth aspect, selecting a source of magnesium-containing silicate; subjecting the selected magnesium-containing silicate source to a base wash by adding a base solution to the magnesium-containing silicate source to produce a magnesium hydroxide material solution; and mixing the resulting magnesium hydroxide material solution with the water and the metal hydroxide-containing solution to form a composition. Including, There is provided a method for producing a composition substantially as described above.

[0123] The base solution can be a metal hydroxide. In one example, the base solution can be sodium hydroxide.

[0124] The magnesium hydroxide material may go into solution during the base wash, as described above. In one embodiment, the resulting magnesium hydroxide material may be at least partially separated from the liquid in the solution. Separation may be via decanting.

[0125] Silica, or iron, or both silica and iron may also be removed from the magnesium hydroxide material. The removal of silica and iron may occur prior to combining the magnesium hydroxide material with the metal hydroxide and water.

[0126] isolation In a seventh aspect, selecting a composition substantially as described above; Exposing the composition to CO2 A method for sequestrating CO2 by the composition reacts with CO to form stable magnesium carbonate and hydrated magnesium carbonate, thus sequestering CO; A method for sequestrating CO2 is provided.

[0127] reaction Magnesium hydroxide can react spontaneously with carbon dioxide (CO2) gas under atmospheric (and near-atmospheric) conditions, as well as at elevated CO2 levels, such as at industrial flue gas sources. This reaction forms stable magnesium carbonate and hydrated magnesium carbonate. However, this reaction may not be the commercially optimal method for sequestering significant volumes of CO2. As shown elsewhere, mixing magnesium hydroxide with metal hydroxides and water substantially accelerates the reaction process, resulting in a commercially useful CO2 sequestration agent.

[0128] Direct air capture or point source capture The inventors have found that the compositions are sensitive and reactive to CO2 and can therefore be used for direct air capture or capture around point sources.

[0129] Exposing the composition to such an environment captures CO directly from the air, hence the term "direct air capture." This sequestration method can be a useful passive means of sequestering ubiquitous CO in the environment.

[0130] Point source capture can refer to exposing a composition at or near the source of CO. The point source can be, for example, an industrial source, a residential source, or a commercial source.

[0131] Composition form The composition may be used in a partially dried form, such as pellets or granules, or as a slurry containing the composition, substantially as described above.

[0132] Reaction rate The rate of reaction can be aided by increasing CO2 concentration and temperature. For example, the more CO2 in the atmosphere or gas (e.g., flue gas) to which the composition is exposed, the faster the reaction rate and CO2 sequestration. This means that the composition may be suitable for sequestration of high CO2 production sources.

[0133] The sequestration reaction rate may proceed more rapidly in the presence of water. Water may be present as moisture. Moisture may be present in a moderate humidity range, such as 30-90%, or 45-75%, or approximately 60% relative humidity (RH). In the inventor's experience, dry RH (low RH less than 40%) or humid RH greater than 75% tends to have less of an effect on the rate of CO2 sequestration, although sequestration still occurs.

[0134] In the inventors' experience to date, approximately 1.3 tons of magnesium hydroxide in the described composition would be required to sequester one ton of CO2 at 100% efficiency. Actual operating efficiencies will likely be less than 100%, and therefore these figures are presented merely as examples and should not be construed as limiting.

[0135] capture device The described compositions may be incorporated into processes or apparatus, or both, to enhance mass transfer and mixing. The processes / apparatus may include, for example, fluidized beds, wet scrubbers, dry scrubbers, and environmental exposures (e.g., field spraying).

[0136] In point source applications, a slurry of the composition may be used in a wet scrubber configuration, where the slurry may be dispersed as a fine mist within a column of hot gases around the point source, as one example. Alternatively, a dry scrubbing arrangement may use a solid composition, such as pellets or granules, which may be present, for example, in a fluidized bed type scrubber.

[0137] For direct air entrapment applications, the composition in solid form may be used, allowing air to pass over the magnesium material.

[0138] advantage As described above, the inventors have determined that the compositions work synergistically to sequester CO. Magnesium hydroxide materials do sequester CO. The inventors have found that by mixing a metal hydroxide and water with magnesium hydroxide, the rate of CO sequestration by magnesium hydroxide can be catalyzed and rapidly accelerated to an extent that it becomes a rapid and useful method for reducing CO emissions.

[0139] A further advantage identified is that the compositions can be made without using processes that themselves produce CO2, thereby negating any benefit of subsequent sequestration.

[0140] The above embodiments may also generally be said to consist in the parts, elements, and features individually or collectively referred to or indicated in the specification of this application, and any or all combinations of any two or more of said parts, elements, or features.

[0141] Furthermore, when specific integers that have known equivalents in the art to which the embodiments pertain are referred to herein, such known equivalents are deemed to be incorporated herein as if individually set forth. [Example]

[0142] The above compositions, methods of production, and methods of CO2 sequestration will now be described with reference to specific examples.

[0143] Example 1 Examples of compositions in pellet or granule form produced by the inventors are shown in Table 1 below. TIFF2026500453000002.tif79170The pellets or granules produced can be approximately 1 μm to 10 mm in diameter.

[0144] Example 2 Examples of compositions in the form of slurries produced by the inventors are shown in Table 2 below. TIFF2026500453000003.tif79170

[0145] Example 3 In this example, the basic method for producing the composition is described by the following steps: - selecting a magnesium hydroxide material, which may be produced via the processing methods described in the further examples below or may be provided in purified form prior to commencing; - optionally grinding the magnesium hydroxide material to an average particle size of less than 1 mm; - selecting a metal hydroxide, for example NaOH, - mixing water together with a magnesium hydroxide material and a metal hydroxide to form a composition; - optionally adding the silica-containing material, the inert material, and the metal salt; - optionally removing water via drying, - Optionally forming the resulting composition into pellets or granules or a slurry.

[0146] Example 4 In this example, a method for producing magnesium hydroxide is described below in conjunction with the production of the final composition described above, with reference to Figure 1. The steps performed are as follows: - selecting olivine as a source of magnesium-containing silicate as olivine sand or processed olivine-rich rock, in this example the olivine is provided with an average particle size of less than 1 mm; - removing the magnetic iron from the olivine sand (approximately 13% of the total mass of the olivine sand); - then grinding the olivine in a pack mill to an average particle size of 30 μm; - Acid washing is carried out by adding the crushed olivine in a ratio of 50 g per 500 ml of 2M HCl acid at 60°C for approximately 3 hours; - then performing a base wash by adding sodium hydroxide to raise the pH to approximately 4.0 to precipitate silica and to approximately 8.0 to remove iron; - filtering the resulting solution and washing the residue (filter cake), - adding additional base solution (sodium hydroxide) to the permeate to raise the pH to 6 to precipitate any remaining iron; - filtering the solution and washing the residue (filter cake), The permeate produced is primarily a solution of magnesium chloride (MgCl2) at about 1 M with some sodium chloride (NaCl) present, - placing the MgCl2 solution in an electrolytic cell and carrying out electrolysis, recovering chlorine (Cl2) gas from the anode and hydrogen (H2) gas from the cathode, and optionally combining the generated gases to form HCl acid for acid washing of further magnesium-containing silicate sources; The magnesium hydroxide Mg(OH)2 material recovered from the cathode contains approximately 50% water. - A composition is then produced by adding 2 g of sodium hydroxide NaOH powder to 10 g of the recovered magnesium hydroxide Mg(OH) to form high moisture pellets.

[0147] Note that in the above examples, hydrochloric acid may be replaced with sulfuric acid or other acids.

[0148] Example 5 In this example, a method for producing magnesium hydroxide is described below in conjunction with the production of the final composition described above, with reference to Figure 2. The steps performed are as follows: - selecting olivine as a source of magnesium-containing silicate as olivine sand or processed olivine-rich rock, in this example the olivine is provided with an average particle size of less than 1 mm; - removing the magnetic iron from the olivine sand (approximately 13% of the total mass of the olivine sand); - then grinding the olivine in a pack mill to an average particle size of 30 μm; - Acid washing is carried out by adding the crushed olivine in a ratio of 50 g per 500 ml of 2M HCl acid at 60°C for approximately 3 hours; - then performing a first base wash by adding sodium hydroxide to raise the pH to approximately 4.0 to precipitate silica and to approximately 8.0 to remove iron; - filtering the resulting solution and washing the residue (filter cake), - adding additional base solution (sodium hydroxide) to the permeate to raise the pH to 6 to precipitate any remaining iron; - filtering the solution and washing the residue (filter cake), - performing a further base wash by adding a basic solution, NaOH, to the permeate to raise the solution pH to 11 to precipitate magnesium hydroxide. The magnesium hydroxide produced has a water content of approximately 50%. The solution is then filtered, and the residue (filter cake) may be washed with or left with the remaining NaOH. The permeate produced is primarily a solution of approximately 2M NaCl, - Optionally, the permeate solution may be introduced into an electrolytic cell to carry out electrolysis, recovering chlorine (Cl2) gas from the anode and hydrogen (H2) gas from the cathode, and optionally, the generated gases may be combined to form HCl acid for acid washing of further magnesium-containing silicate sources. The magnesium hydroxide Mg(OH)2 material recovered from the cathode contains approximately 50% water. - The composition is then produced by drying the recovered Mg(OH)2 material (approximately 50% mass reduction) to form pellets with a moisture content of 25%. NaOH is also present due to the additional base solution used in the magnesium precipitation step. additional NaOH may be added to the recovered magnesium hydroxide material Mg(OH)2, if necessary; - A process in which silica or clay may also be added.

[0149] Note that in the above examples, hydrochloric acid may be replaced with sulfuric acid or other acids.

[0150] Example 6 With reference to FIG. 3, an example of a method for producing a composition by direct NaOH addition is described below (Note: this differs from the base wash described in other examples where the wash results in a pH increase for product isolation): - Obtain magnesium hydroxide material from any source (i.e., commercially available). Where applicable, the magnesium hydroxide material may be ground to an average particle size of less than 1 mm. A solution containing a mixture of NaOH (or other metal hydroxide) and water can be added to the magnesium hydroxide material. The metal hydroxide concentration of the solution is adjusted to produce a final material having a composition as set forth in Table 1 (pelletized) or Table 2 (slurry). Alternatively, solid NaOH is combined with magnesium hydroxide and water is added to obtain the compositions outlined in Tables 1 and 2. -Clay, silica, or other materials may be added to the mixture. The mixture may be processed into pellets, which will typically be around 1 mm in diameter (but may be between 1 um and 10 mm). Alternatively, the mixture can be maintained as a slurry.

[0151] Example 7 With reference to Figures 4-8, a method of CO2 sequestration using the composition is described.

[0152] Direct Air Capture Typically, the composition can be used such that air is passed over the composition. Figure 4 illustrates this reaction, where the composition is in pelletized form and reacts spontaneously with carbon dioxide gas (atmospheric or point source) to produce the hydrated magnesium carbonate end product.

[0153] The above reaction may occur using an apparatus as shown in Figure 5. In experiments performed by the inventors using the apparatus of Figure 5 as a closed system, the first measurement was a control in which no composition was added to the stream through the cell shown. A steady-state atmospheric CO2 reading was recorded at approximately 400 ppm. Five grams of the pelletized composition was placed in the stream through the cell, and CO2 level readings were then taken over time. The CO2 readings decreased from a starting value of approximately 400 ppm to less than 200 ppm over a 24-hour period, demonstrating the CO2 absorption properties of the composition.

[0154] Point Source Carbon Capture Alternatively, a slurry of the composition may be used in a wet scrubber configuration, where the slurry is dispersed as a fine mist within a column of hot gases as shown in FIG.

[0155] In a further alternative, a dry scrubber configuration may use a pelletized composition (e.g., in a fluidized bed scrubber). To demonstrate the carbon absorption reaction for this alternative, an experiment was performed by the inventors as follows: Approximately 5 grams of the composition is placed in a beaker containing deionized water; Concentrated CO2 (approximately 99%) was passed through the cell for approximately 1 hour.

[0156] Following CO2 addition, thermogravimetric analysis results and acidity tests confirmed the presence of highly carbonated material, demonstrating carbon uptake.

[0157] Underwater carbon capture A further method for sequestration can be via bubbling CO2 through a slurry containing the composition, as shown in Figure 7.

[0158] To further demonstrate this isolation method, an experiment was performed as follows: Approximately 21 grams of the composition was placed in a beaker containing deionized water; Concentrated CO2 (approximately 99%) was bubbled through the beaker for approximately 15 minutes.

[0159] Thermogravimetric analysis results after exposing the composition to CO2 bubbling, shown in Figure 8, indicate that the material was a hydrated magnesium carbonate similar to hydromagnesite.

[0160] X-ray diffraction (XRD) results after exposing the composition to CO2 bubbling, shown in Figure 9, indicate that the material was hydrated magnesium carbonate, similar to hydromagnesite.

[0161] Example 8 Tests were performed to determine the catalytic effect of metal hydroxides on the rate of sequestration.

[0162] A sequestration demonstration apparatus was prepared similarly to that described above in Example 7. Tests were performed using sodium hydroxide as the metal hydroxide and carbon dioxide sequestration was measured over a 10 minute period.

[0163] Figure 10 shows a graph of the test results. Samples were taken for a magnesium hydroxide-only slurry (labeled 0% NaOH), a 10% sodium hydroxide slurry, a water sponge alone, and a no-DAC sample. The water (labeled "H2O sponge") served as a control to evaluate the water's ability to capture CO2, while the "no-DAC" label represented the absence of any sorbent or water in the absorption loop. As expected, the "no-DAC" and H2O sponge controls had no effect on CO2 sequestration. The 0% slurry had little effect, with CO2 levels dropping from 500 ppm / min to 450 ppm / min after 10 minutes. The 10% slurry, on the other hand, showed a rapid and immediate decrease in CO2, going from 500 ppm / min at the start of the test to approximately 350 ppm / min after 10 minutes. The 10% NaOH addition resulted in a 30% decrease in CO2, while the no-NaOH addition resulted in only a 10% decrease.

[0164] At values ​​below 1% metal hydroxide (not shown in FIG. 10), CO2 capture was similar to the 0% NaOH plot shown. At values ​​above 1% NaOH, CO2 capture moved away from the 0% line. At 10% NaOH, we achieved the highest sequestration rate. Increasing NaOH above 10% did not change the CO2 uptake rate. 100% NaOH, as expected, had the least effect on CO2 sequestration. Amounts above 20% NaOH were ignored because having so much sodium is not ideal for the formation of Mg carbonate, given the size and amount of sodium. High levels of sodium would also be detrimental to end use as a potential residue.

[0165] It should be appreciated that embodiments of the compositions, methods of production, and methods of CO2 sequestration have been described by way of example only, and that modifications and additions can be made to such embodiments without departing from the scope of the claims of the present invention.

Claims

1. CO ２ Exposed to CO ２ to form stable magnesium carbonate and hydrated magnesium carbonate, thus CO ２ 1. A composition configured to sequester CO ２ Segregated concentration magnesium hydroxide material, water, and Catalytic concentrations of metal hydroxides Including, The metal hydroxide is an alkali metal but is not magnesium hydroxide; composition.

2. 10. The composition of claim 1, wherein the magnesium hydroxide material is derived from olivine, serpentine group minerals, pyroxene, amphibole, and combinations thereof.

3. 3. The composition of claim 1 or claim 2, comprising approximately 60-90% by weight of magnesium hydroxide material.

4. 4. The composition of claim 1, comprising at least 5% by weight of water.

5. Metal hydroxide is NaOH, LiOH or KOH, Ca(OH) ２ 5. The composition of claim 1, wherein the hydroxybenzoate is selected from the group consisting of hydroxybenzoates, ...

6. 5. The composition of claim 1, wherein the metal hydroxide is NaOH alone.

7. 7. The composition of any one of claims 1 to 6, comprising approximately 1 to 10% by weight of a metal hydroxide.

8. 70 to 80 wt. % of said magnesium hydroxide material; greater than 5% by weight of said water, and 1 to 10% by weight of said metal hydroxide The composition of any one of claims 1 to 7, comprising:

9. configured as pellets, granules, or a slurry; 9. The composition of any one of claims 1 to 8.

10. The composition of any one of claims 1 to 7, constituted as a slurry having a solids content of 1 to 50% by weight.

11. The composition of claim 10 having a solids content of 5 to 15% by weight.

12. 12. The composition of any one of claims 1 to 11, further comprising less than approximately 50% by weight of a silica-containing material.

13. 13. The composition of claim 12, wherein the silica-containing material is clay, quartz, or other siliceous mineral.

14. 14. The composition of any one of claims 1 to 13, further comprising an inert material selected from carbonates, silicates, oxides, sulfates, and combinations thereof.

15. 14. The composition of any one of claims 1 to 13, further comprising an inert material selected from clay minerals, quartz, zeolites, calcite, magnetite, magnesite, and combinations thereof.

16. LiCl, NaCl, KCl, MgCl ２ , Na ２ SO ４ , MgSO ４ , CaSO ４ , Li ２ SO ４ , CaCl ２ 16. The composition of claim 1, further comprising a metal salt selected from:

17. selecting a source of magnesium-containing silicate; subjecting the selected magnesium-containing silicate source to an acid wash to produce an acid digestion solution; subjecting the acid decomposition liquid to a base wash by adding a base solution to the acid decomposition liquid to produce a magnesium salt solution, and during this process removing silica, iron, or other metals and minerals from the magnesium salt solution; subjecting the magnesium salt solution to electrolysis to recover a magnesium hydroxide material; and mixing the recovered magnesium hydroxide material with said water and said metal hydroxide containing solution to form a composition. Including, 17. A method for producing a composition according to any one of claims 1 to 16.

18. selecting a source of magnesium-containing silicate; subjecting the selected magnesium-containing silicate source to a base wash by adding a base solution to the magnesium-containing silicate source to produce a magnesium hydroxide material solution; and mixing the resulting magnesium hydroxide material solution with the water and the metal hydroxide-containing solution to form a composition. Including, 17. A method for producing a composition according to any one of claims 1 to 16.

19. selecting a source of magnesium-containing silicate; subjecting the selected magnesium-containing silicate source to an acid wash to produce an acid digestion solution; subjecting the acid decomposition liquid to a base wash by adding a base solution to the acid decomposition liquid to produce a magnesium salt solution, and during this process removing silica, iron, or other metals and minerals from the magnesium salt solution; performing a further base wash of the magnesium salt solution to produce a magnesium hydroxide material in solution, and filtering the magnesium hydroxide material in solution to recover the magnesium hydroxide material and the separated metal salt solution; and mixing the recovered magnesium hydroxide material with said water and said metal hydroxide containing solution to form a composition. Including, 17. A method for producing a composition according to any one of claims 1 to 16.

20. 20. The method of claim 19, wherein the separated metal salt solution is subjected to electrolysis to produce an acid solution, a base solution, and an evolved gas.

21. Selecting a composition according to any one of claims 1 to 16, and The composition ２ Exposure to CO ２ A method for isolating a The composition is CO ２ to form stable magnesium carbonate and hydrated magnesium carbonate, thus CO ２ Isolate the CO ２ Isolation methods.

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