Process for preparing amorphous calcium carbonate by immobilizing carbon dioxide

Abstract

Methods for immobilizing carbon dioxide and producing stabilized amorphous alkaline earth metal carbonates are provided.

Description

Field of the Invention

[0001] The present invention relates to a method for using and fixing carbon dioxide gas to prepare stabilized amorphous calcium carbonate. Background of the Invention

[0002] Climate change is considered a major challenge for contemporary society. Generally, driven by greenhouse gases, carbon dioxide (CO2), as the most common greenhouse gas, is a major contributor to global warming. More than 40% of energy-related CO2 emissions are due to the combustion of fossil fuels for power generation.

[0003] Inorganic carbonation processes have previously been proposed and even practiced to fix CO2 mainly generated by power plants and other energy-consuming manufacturing facilities. In these cases, the idea is to capture the exhausted CO2 in a controlled manner and then release it again in a controlled manner by filling CO2 reservoirs, dumping it into the deep sea, and absorbing it into certain geological components. Existing processes have drawbacks such as energy consumption, efficiency, and process costs (partially attributed to the high cost of mineral reagents). They also rely on the use of capture agents or ammonia, such as Ca(OH)2 and CaO, which are produced by releasing CO2 from CaCO3 mined from the earth. These processes also require the release and capture of CO2 elsewhere during energy-consuming processes, while still needing to dump (''store'') this CO2 elsewhere on earth or convert it into useful organic products. The latter concept has been studied for 40 years without any useful potential for large-scale, low energy consumption, and commercialization of derived products.

[0004] It is well known that under alkaline conditions (i.e., high pH, high concentration of OH - ), CO2 can be converted into bicarbonate or carbonate (depending on the pH). It is also well known that calcium ion salts such as calcium chloride and calcium nitrate can in particular be converted into Ca(OH)2, which can then react with CO2 to form crystalline CaCO3.

[0005] The solubility of CO2 at atmospheric pressure and 25 °C is very low, with approximately 1.5 g of CO2 dissolving in 1 L of water at atmospheric pressure. At room temperature and atmospheric pressure, the low solubility of CO2 in water makes it impractical to capture large amounts of rapidly released CO2 by calcium reagents such as CaCl2·2H2O, calcium nitrate, and Ca(OH)2 in a closed reactor unless the pressure is increased.

[0006] Graphs of CO2 solubility relative to pressure generally show that at 1 atm, the solubility in water is about 1.5 g / 1 Kg water at 25 °C, which slightly depends on the water content. When CO2 is pressurized, the solubility increases significantly. At about 50 atm, the solubility reaches over 50 g CO2 / Kg water. Thus, one way to improve process efficiency described in the present invention is to introduce CO2 in a pressurized mode.

[0007] Chemical equilibrium shifts the conversion reaction that is mainly CO2 at pH 5 to a conversion reaction that is mainly (over 90%) bicarbonate at pH levels of 7 and 11 and finally carbonate. At pH levels below 4 and 5, CO2 is converted to carbonic acid, which enhances the acidity of the aqueous solution and keeps most of the CO2 in its original form.

[0008] The large-scale production of other carbonates and minerals sometimes involves the large-scale production of CaCl2 hydrate and CaSO4 hydrate as industrial wastes. For example, CaCl2 is a by-product in the process of soda ash (Na2CO3) called the "Solvay Process". Park et al. (Journal of Hazardous Materials 403 (2021) 123862) disclosed the use of a process for converting Ca(OH)2 to calcium carbonate by reacting Ca(OH)2 with CO2. If such industrial wastes can be reused at no cost or at a small fraction of their cost, the economics of capturing CO2 in any form of calcium carbonate will offset the costs associated with continuous CO2 capture.

[0009] Due to the parallel of global industrialization with the dangerous greenhouse effect and climate change, there is an urgent need to develop new technologies for removing CO2 from the atmosphere. Summary of the Invention

[0010] Surprisingly, it was found that by adjusting the physicochemical conditions, CO2 gas can be fixed in an industrially profitable manner at room temperature and a large amount of stabilized amorphous calcium carbonate can be produced. In the laboratory-scale reaction provided in the examples, about 3.8 g of CO2 reacted with about 13 g of CaCl2•2H2O for the synthesis of ACC in a 250 ml reaction volume solution at room temperature with a total yield of 10.5 g in the presence of stabilizers such as tripolyphosphoric acid / tripolyphosphate / tripolyphosphite (as a representative stabilizer), provided that CO2 was converted to CO3 -Examples show that an ACC production yield of up to 90% and a phase purity of 90% (i.e., amorphous material) can be achieved. It is shown in the present invention that the yield is increased by adding CO2 to an alkaline solution and in-situ obtaining soluble (Na)2CO3 as a first step. Alternatively, an alkali can be added to a solution of calcium chloride or calcium nitrate to convert them in-situ to calcium hydroxide, which captures CO2 in the presence of a stabilizer to form ACC.

[0011] Furthermore, the ACC production yield can be increased by changing the schedule of adding the stabilizer and / or by increasing the pH of the reaction. As shown in Example 2, the yield is increased by adding the stabilizer in two different stages.

[0012] Without being limited by any particular theory, it is estimated that three to four equilibrium reactions occur.

[0013] The main reactions are: 。

[0014] Additional reactions that may occur after adding CaCl2 are: 。

[0015] Under laboratory conditions, we conclude that the reaction may be completed in less than two minutes. Similar reactions can be carried out in the presence of dissolved ammonia (and thus NH4OH). NH4OH refers to the product of dissolving ammonia (NH3) in water. Thus, the reaction with this base can be carried out by using pre-dissolved ammonia defined as NH4OH or by directly bubbling or pressurizing ammonia into the reaction solution to in-situ form NH4OH.

[0016] By fixing CO2 and converting CaCl2 to ACC, the present invention actually solves three problems: fixing environmentally harmful CO2, disposing of CaCl2 waste, and mass-producing ACC. When ACC is produced at the lower purity required for its use as a food supplement or drug, ACC can be used in agriculture, such as for crop fertilization, as a supplement for livestock animals, etc. In some industrial processes, calcium oxide can be produced as a by-product. Although calcium oxide can be used to form cement and glass, it can also be used to form calcium hydroxide, which can be converted to ACC according to the present invention. Similar processes can be carried out using MgCl2, Mg(NO3)2, MgSO4, Mg(OH)2, and MgO waste in the presence of a base, a stabilizer, and CO2 bubbling to obtain an amorphous magnesium carbonate phase.

[0017] It is important to maintain a sufficiently high pH (above 8) throughout the process by adding sufficient base (2 equivalents or more of calcium present in the reaction) or by adding base continuously or incrementally to keep the pH above 8 and preferably above 11. Generally, it is possible to achieve the formation of calcium carbonate precipitation at a pH below 10, but then most of the CO2 is in the form of dissolved bicarbonate, and the calcium carbonate obtained by partially decomposing the bicarbonate back to CO2 is produced in low yield. A pH above 11 is also an option as it may affect the primary particle size and amorphous phase of calcium carbonate.

[0018] The use of amorphous calcium carbonate (ACC) with controlled cleanliness and content has been demonstrated and reported in a series of patents and publications for a wide range of biomedical applications. Less clean but very large amounts of ACC can be used as a beneficial fertilizer and feedstock for animals such as chickens and cows, provided that the toxic metals in the calcium-based by-products do not exceed ppm levels. If such ACC can be produced at a fraction of the cost of the ACC currently used as a food supplement or drug, it will enhance and improve the quality of agricultural crops, fruits, and vegetables as well as healthier livestock.

[0019] According to one aspect, the present invention provides a method for preparing a stabilized amorphous alkaline earth metal carbonate, the method comprising: (i) dissolving a base in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) bubbling or pressurizing CO2 gas into the solution obtained in step (i), followed by adding a salt of an alkaline earth metal; or adding a salt of an alkaline earth metal to the solution obtained in step (i), followed by bubbling or pressurizing CO2 gas into the solution, thereby precipitating an amorphous alkaline earth metal carbonate, and (iii) collecting the resulting stabilized amorphous alkaline earth metal carbonate precipitate, wherein the method comprises adding at least one stabilizer in at least one of the following stages: (a) before bubbling or pressurizing CO2 gas; (b) after bubbling or pressurizing CO2 gas; (c) before adding a salt of an alkaline earth metal, (d) together with adding a salt of an alkaline earth metal, or (e) after adding a salt of an alkaline earth metal.

[0020] According to some embodiments, the stabilizer is added after bubbling or pressurizing CO2 gas and together with adding a salt of an alkaline earth metal.

[0021] According to some embodiments, the method comprises: (i) dissolving a base in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) Bubbling or pressurizing CO2 gas into the solution obtained in step (i), and subsequently adding a salt of an alkaline earth metal; and (iii) Collecting the resulting stabilized amorphous alkaline earth metal carbonate precipitate.

[0022] In some embodiments, the method includes adding a stabilizer before bubbling or pressurizing CO2 gas into the solution obtained in step (i). In some embodiments, the method includes adding a stabilizer after adding the salt of the alkaline earth metal. In some embodiments, the method includes adding a stabilizer before bubbling or pressurizing CO2 gas into the solution obtained in step (i) and after adding the salt of the alkaline earth metal.

[0023] According to some embodiments, the method includes: (i) Dissolving an alkali in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) Adding a salt of an alkaline earth metal to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas into the solution, (iii) Collecting the resulting stabilized amorphous alkaline earth metal carbonate precipitate.

[0024] According to some embodiments, the method includes adding a stabilizer together with the addition of the salt of the alkaline earth metal. According to some embodiments, the method includes adding a stabilizer before bubbling or pressurizing CO2 gas into the solution obtained in step (i). According to some embodiments, the method includes adding a stabilizer together with the addition of the salt of the alkaline earth metal and further before bubbling or pressurizing.

[0025] According to some embodiments, the method includes, as a first step, dissolving an alkali and a stabilizer in an aqueous solution. Thus, according to some embodiments, the present invention provides a method for preparing a stabilized alkaline earth metal carbonate, the method comprising: (i) Dissolving an alkali and a stabilizer in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) Bubbling or pressurizing CO2 gas into the solution obtained in step (i), and subsequently adding a salt of an alkaline earth metal and optionally a stabilizer to the solution; or adding a salt of an alkaline earth metal to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas into the solution and optionally adding a stabilizer, thereby precipitating a stabilized amorphous alkaline earth metal carbonate; (iii) Optionally adding a stabilizer to the solution obtained in step (ii), and (iv) Collecting the resulting stabilized amorphous alkaline earth metal carbonate, wherein CO2 is continuously introduced into the solution during step (ii) and step (iii) (if present), and the stabilizer in step (i) and step (ii) and / or step (iii) (if present) is the same or different.

[0026] According to some embodiments, step (ii) includes bubbling or pressurizing CO2 gas into the solution obtained in step (i), followed by adding a salt of an alkaline earth metal. Thus, according to some embodiments, the method includes the following steps: (i) Dissolving an alkali and a stabilizer in an aqueous solution; (ii) Bubbling or pressurizing CO2 gas into the solution obtained in step (i), followed by adding a salt of an alkaline earth metal and optionally a stabilizer to the solution; (iii) Optionally adding a stabilizer to the solution obtained in step (ii), and (iv) Collecting the resulting stabilized amorphous alkaline earth metal carbonate.

[0027] According to another embodiment, step (ii) includes adding a salt of an alkaline earth metal to the solution obtained in step (i), followed by bubbling or pressurizing CO2 gas into the solution. Thus, according to some embodiments, the method includes the following steps: (i) Dissolving an alkali and a stabilizer in an aqueous solution; (ii) Adding a salt of an alkaline earth metal and optionally a stabilizer to the solution obtained in step (i), followed by bubbling or pressurizing CO2 gas; (iii) Optionally adding a stabilizer to the solution obtained in step (ii), and (iv) Collecting the resulting stabilized amorphous alkaline earth metal carbonate.

[0028] According to some embodiments, the present invention provides a method for preparing a stabilized amorphous alkaline earth metal carbonate, the method comprising: (i) Dissolving an alkali in an aqueous solution; (ii) Dissolving a stabilizer in the solution obtained in step (a), and bubbling or pressurizing CO2 gas into the solution, wherein dissolving the stabilizer and initiating CO2 introduction by bubbling or pressurizing are carried out in either order; (iii) Adding a salt of an alkaline earth metal and optionally a stabilizer to the solution obtained in step (b), thereby precipitating the stabilized amorphous alkaline earth metal carbonate; and (iv) Optionally adding a stabilizer to the solution obtained in step (c), Among them, CO2 is continuously introduced into the solution during step (b) and step (c), and the stabilizers in step (b) and step (c) and / or step (d) (if added) are the same or different.

[0029] According to some embodiments, the pH of the solution obtained after adding the base in step (i) is equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12. According to some embodiments, the pH of the solution obtained in step (i) is equal to or higher than 9. According to some embodiments, the pH of the solution obtained in step (i) is equal to or higher than 10. According to some embodiments, the pH of the solution obtained in step (i) is equal to or higher than 11. According to some embodiments, the pH of the solution obtained in step (i) is equal to or higher than 12. The term "pH equal to or higher than X" can be replaced by any one of the terms "pH equal to X", "pH greater than X", "pH higher than X", "pH is X or greater", etc.

[0030] According to some embodiments, the precipitation of the amorphous alkaline earth metal carbonate is completed within 2 minutes.

[0031] According to some embodiments, the method includes adding a stabilizer in step (ii). Thus, according to some embodiments, step (ii) includes bubbling or pressurizing CO2 gas into the solution obtained in step (i), followed by adding a salt of an alkaline earth metal and adding a stabilizer. According to other embodiments, step (ii) includes adding a salt of an alkaline earth metal and a stabilizer to the solution obtained in step (i), followed by bubbling or pressurizing CO2 gas. According to some embodiments, the stabilizer added in step (i) and step (ii) is the same stabilizer. According to some embodiments, the stabilizers added in step (i) and step (ii) are different stabilizers.

[0032] According to some embodiments, the method includes adding a stabilizer only in steps (i) and (ii). According to some embodiments, the method includes adding a stabilizer in step (iii). According to some embodiments, the method includes adding a stabilizer only in steps (i) and (iii). According to some embodiments, the stabilizer added in steps (i) and (iii) is the same stabilizer. According to some embodiments, the stabilizers added in steps (i) and (iii) are different stabilizers. According to some embodiments, the method includes adding a stabilizer in steps (ii) and (iii). According to some embodiments, when adding a stabilizer in multiple steps, the stabilizer can be different in each step. According to other embodiments, the stabilizer in all steps can be the same stabilizer. In some instances, the method includes adding a stabilizer in step (iv). In some instances, the stabilizer in steps (ii) and (iv) is the same stabilizer. Similar processes can be used for other alkaline earth metal by-products. In an alternative process, the base and stabilizer can (i) be added to the alkaline earth metal solution or slurry, and then (ii) CO2 can be purged to form amorphous metal carbonate. The amounts of all stabilizers can be added to the solution all at once before CO2 purging. In other cases, the stabilizer can be added to the solution partially before purging and partially after purging.

[0033] In some instances, the process is carried out batchwise. In other instances, the process can be carried out in a series of batch reactors. In some instances, the process can be carried out continuously. In this case, the completion time is not a factor, but the time to remove the formed product is preferably completed within a few minutes, preferably less than 10 minutes, less than 5 minutes, less than 3 minutes, or less than or equal to 2 minutes.

[0034] According to some embodiments, the present invention provides a continuous method for preparing stabilized amorphous alkaline earth metal carbonate, the method comprising: providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding a base, at least one stabilizer, and an alkaline earth metal to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) continuously collecting the resulting amorphous alkaline earth metal carbonate precipitate, wherein the pH is constantly maintained equal to or higher than 8 throughout the process.

[0035] In some instances, the base is selected from hydroxides of alkali metals, ammonia, or ammonium hydroxide. In some embodiments, the base is sodium hydroxide. In another embodiment, the base is ammonium hydroxide.

[0036] In any of the above and below embodiments, the salt of the alkaline earth metal is water-soluble. In some instances, the salt of the alkaline earth metal is selected from the water-soluble halides, nitrates, and sulfates of the metal and their hydrates. In some instances, the salt of the alkaline earth metal is selected from calcium chloride, calcium bromide, calcium nitrate, magnesium chloride, magnesium sulfate, magnesium nitrate, and combinations thereof. In one instance, the salt of the alkaline earth metal is calcium chloride. In some instances, the salt of the alkaline earth metal is magnesium chloride. In other instances, the salt of the alkaline earth metal is magnesium sulfate. In another embodiment, the salt of the alkaline earth metal is a combination of calcium chloride and magnesium sulfate. According to some embodiments, the method includes adding the salt of the alkaline earth metal and / or maintaining its concentration at from 0.02 M to 0.1 M (moles, mol / L). According to some embodiments, the method includes adding CaCl2 and / or maintaining its concentration in the range from 0.03 M to 0.8 M. According to some embodiments, the method includes adding MgSO4 and / or maintaining its concentration in the range from 0.04 M to 1 M.

[0037] In some instances, the stabilizer is selected from the group consisting of: polyphosphoric acid / polyphosphate / polyphosphonate, inorganic polyphosphoric acid / polyphosphate / polyphosphonate, organic acid, phosphorylated amino acid, phosphorylated, phosphonated, sulfated, or sulfonated organic compound, phosphate or sulfate ester of hydroxycarboxylic acid, bisphosphonic acid / bisphosphate / bisphosphonate, organic polyphosphoric acid / polyphosphate / polyphosphonate, polyphosphoric acid / polyphosphate / polyphosphonate, organic compound having a hydroxy group, its derivative, protein, any salt thereof, and any combination thereof. In some instances, the stabilizer is selected from the group consisting of: triphosphate or its salt, phosphoserine, citric acid, sodium tripolyphosphate and citric acid, adenosine triphosphate, adenosine diphosphate, phytic acid, etidronic acid, pyrophosphoric acid / pyrophosphate / pyrophosphonate, polyphosphoric acid / polyphosphate / polyphosphonate, hexametaphosphoric acid / hexametaphosphate / hexametaphosphonate, ethanol, its salt, and any combination thereof. In some instances, the stabilizer is sodium tripolyphosphate. In some embodiments, the stabilizer is selected from triphosphoric acid / triphosphate / triphosphonate, pyrophosphoric acid / pyrophosphate / pyrophosphonate, hexametaphosphoric acid / hexametaphosphate / hexametaphosphonate, phytic acid, citric acid, and combinations thereof. According to one embodiment, the stabilizer is a combination of triphosphoric acid / triphosphate / triphosphonate and pyrophosphoric acid / pyrophosphate / pyrophosphonate, or a combination of triphosphoric acid / triphosphate / triphosphonate and hexametaphosphoric acid / hexametaphosphate / hexametaphosphonate, or a combination of triphosphoric acid / triphosphate / triphosphonate and phytic acid, or a combination of triphosphoric acid / triphosphate / triphosphonate and citric acid.

[0038] In some instances, the pH in step (i) is higher than 8, higher than 10, or higher than 12. In some instances, the pH in step (i) is from 8 to 13, from 8 to 12, from 9 to 12, from 9 to 11, from 10 to 12, or from 10 to 13.

[0039] In some instances, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the preparation process. In some instances, the pH is maintained at a value from 8 to 13, from 8 to 12, from 9 to 12, from 9 to 11, from 10 to 12, or from 10 to 13 throughout the preparation process.

[0040] In some instances, the amount of base is at least 2 molar equivalents of the amount of the alkaline earth metal salt. In some instances, the concentration of the base is at least 2 molar equivalents of the concentration of the alkaline earth metal salt. In some instances, the concentration of the base is maintained at at least 2 molar equivalents of the concentration of the alkaline earth metal salt.

[0041] The terms “at least X” and “X or greater” mean a value of X or greater. This term may be replaced by a phrase that limits an upper limit as defined in the embodiments of the present application.

[0042] In some instances, the total amount of stabilizer added is from 2 wt% to 15 wt% of the amount of the alkaline earth metal salt. In some instances, the cumulative concentration of the stabilizer added is from 2 wt% to 15 wt% of the concentration of the alkaline earth metal salt. In some instances, the cumulative concentration of the stabilizer added is maintained constant at from 2 wt% to 15 wt% of the concentration of the alkaline earth metal salt.

[0043] In some instances, the reaction is carried out at atmospheric pressure. In some instances, the reaction is carried out at a pressure from 1 bar to 60 bar.

[0044] In some instances, wherein the reaction is carried out at ambient temperature.

[0045] In some instances, for example, the precipitation of stabilized amorphous alkaline earth metal carbonates such as ACC and AMC in step (iii) is completed within 2 to 3 minutes, optionally followed by the addition of a stabilizer in step (iv).

[0046] According to some embodiments, the entire precipitation process of the stabilized amorphous alkaline earth metal carbonates such as ACC and AMC is completed within 2 minutes from the start of precipitation.

[0047] According to some embodiments, collecting the stabilized amorphous alkaline earth metal carbonates includes filtering and / or drying the obtained amorphous alkaline earth metal carbonate precipitate.

[0048] In some instances, the present invention provides a method that includes the following steps: (i) Dissolve an alkali and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the resulting aqueous solution is 8 or greater; (ii) Bubble or pressurize CO2 into the solution obtained in step (i), and subsequently add CaCl2 to the solution and optionally add sodium tripolyphosphate as a stabilizer; (iii) Optionally add sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) Collect the resulting stabilized amorphous calcium carbonate, wherein the alkali is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of CaCl2, and optionally wherein CaCl2 is selected from anhydrous CaCl2, CaCl2 monohydrate, and CaCl2 dihydrate. In some embodiments, the method includes adding a stabilizer in step (iii). In some embodiments, the alkali is selected from NaOH or NH4OH and is added in an amount equal to 2 molar equivalents or 3 molar equivalents of CaCl2. According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the preparation process. According to some embodiments, the pH is maintained at a value between 8 and 13 throughout the preparation process.

[0049] In some instances, the present invention provides a method that includes the following steps: (i) Dissolve an alkali and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the resulting aqueous solution is 8 or greater; (ii) Add CaCl2, and subsequently bubble or pressurize the CO2 gas; (iii) Optionally add sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) Collect the resulting stabilized amorphous calcium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of CaCl2, and optionally wherein CaCl2 is selected from anhydrous CaCl2, CaCl2 monohydrate or CaCl2 dihydrate. In some embodiments, the method includes adding a stabilizer in step (iii). In some embodiments, the base is selected from NaOH or NH4OH and is added in an amount equal to 2 or 3 molar equivalents of CaCl2. According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11 or equal to or higher than 12 during the entire preparation process. According to some embodiments, the pH is maintained at a value between 8 and 13 during the entire preparation process.

[0050] In some instances, the present invention provides a method that includes the following steps: (i) Dissolving a base and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the resulting aqueous solution is 8 or greater; (ii) Bubbling or pressurizing CO2 gas into the solution obtained in step (i), and subsequently adding MgSO4 to the solution; (iii) Optionally adding sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) Collecting the resulting stabilized amorphous magnesium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of MgSO4, and optionally wherein MgSO4 is anhydrous MgSO4 or MgSO4 heptahydrate. In some embodiments, the method includes adding a stabilizer in step (iii). In some embodiments, the base is selected from NaOH or NH4OH and is added in an amount equal to 2 or 3 molar equivalents of CaCl2 or MgSO4. According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11 or equal to or higher than 12 during the entire preparation process. According to some embodiments, the pH is maintained at a value between 8 and 13 during the entire preparation process.

[0051] In some instances, the present invention provides a method that includes the following steps: (i) Dissolving a base and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the resulting aqueous solution is 8 or greater; (ii) Adding MgSO4 and optionally sodium tripolyphosphate as a stabilizer to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas into the solution; (iii) Optionally adding sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) Collect the obtained stabilized amorphous magnesium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of MgSO4, and optionally wherein the MgSO4 is anhydrous MgSO4 or MgSO4 heptahydrate. In some embodiments, the method includes adding a stabilizer in step (iii). In some embodiments, the base is selected from NaOH or NH4OH and is added in an amount equal to 2 or 3 molar equivalents of MgSO4. According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the preparation process. According to some embodiments, the pH is maintained at a value between 8 and 13 throughout the preparation process.

[0052] In some instances, the present invention provides a method that includes providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding a base, sodium tripolyphosphate, and calcium chloride to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) continuously collecting the obtained amorphous calcium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount of at least 2 molar equivalents of calcium chloride, and wherein the pH is constantly maintained equal to or higher than 8 throughout the process. According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the preparation process. According to some embodiments, the pH is maintained at a value between 8 and 13 throughout the preparation process.

[0053] In some instances, the present invention provides a method that includes: providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding a base, sodium tripolyphosphate, and magnesium sulfate to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) continuously collecting the obtained amorphous magnesium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount of at least 2 molar equivalents of magnesium sulfate, and wherein the pH is constantly maintained equal to or higher than 8 throughout the process. According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the preparation process. According to some embodiments, the pH is maintained at a value between 8 and 13 throughout the preparation process.

[0054] According to another aspect, the present invention provides a stabilized amorphous alkaline earth metal carbonate, which is prepared by the method according to any one of the above examples. According to some examples, the present invention provides a stabilized amorphous calcium carbonate, which is prepared by the method according to any one of the above examples. According to some examples, the present invention provides a stabilized amorphous magnesium carbonate, which is prepared by the method according to any one of the above examples. According to some embodiments, the present invention provides a stabilized amorphous alkaline earth metal carbonate, which is obtained or obtainable by the method according to any one of the above examples. According to some embodiments, the present invention provides a stabilized amorphous carbonate, which is obtained or obtainable by the method according to any one of the above examples. According to another aspect, the present invention provides the use of the stabilized ACC prepared by the method of the present invention in agriculture and veterinary medicine. DETAILED DESCRIPTION OF THE INVENTION

[0055] According to one aspect, the present invention provides a method for preparing a stabilized alkaline earth metal carbonate, the method comprising: (i) dissolving an alkali in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) bubbling or pressurizing CO2 gas into the solution obtained in step (i), and then adding a salt of an alkaline earth metal; or adding a salt of an alkaline earth metal to the solution obtained in step (i), and then bubbling or pressurizing CO2 gas into the solution, thereby precipitating an amorphous alkaline earth metal carbonate, and (iii) collecting the resulting precipitate of the stabilized amorphous alkaline earth metal carbonate, wherein the method comprises adding at least one stabilizer in at least one stage during the preparation process. Non-limiting examples of the stage are: (a) before bubbling or pressurizing the CO2 gas; (b) after bubbling or pressurizing the CO2 gas; (c) before adding the salt of the alkaline earth metal, (d) together with adding the salt of the alkaline earth metal, or (e) after adding the salt of the alkaline earth metal.

[0056] Thus, according to some embodiments, the present invention provides a method for preparing a stabilized amorphous alkaline earth metal carbonate, the method comprising: (i) dissolving an alkali in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) bubbling or pressurizing CO2 gas into the solution obtained in step (i), and then adding a salt of an alkaline earth metal; or adding a salt of an alkaline earth metal to the solution obtained in step (i), and then bubbling or pressurizing CO2 gas into the solution, thereby precipitating an amorphous alkaline earth metal carbonate, and (iii) Collect the obtained amorphous alkaline earth metal carbonate precipitate, wherein the method comprises adding at least one stabilizer in at least one of the following stages: (a) before bubbling or pressurizing the CO2 gas; (b) after bubbling or pressurizing the CO2 gas; (c) before adding the salt of the alkaline earth metal, (d) together with the addition of the salt of the alkaline earth metal, or (e) after adding the salt of the alkaline earth metal.

[0057] The term "aqueous solution" refers to a composition comprising at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or 100% water. In a preferred embodiment, the term "aqueous solution" refers to "water", such as distilled water, double-distilled water or any other aqueous solution well known in the art.

[0058] According to some embodiments, the stabilizer is added before bubbling or pressurizing the CO2 gas. According to some embodiments, the stabilizer is added after bubbling or pressurizing the CO2 gas. According to some embodiments, the stabilizer is added before adding the salt of the alkaline earth metal. According to some embodiments, the stabilizer is added together with the addition of the salt of the alkaline earth metal, for example by mixing the salt of the alkaline earth metal and the stabilizer together. According to some embodiments, the stabilizer is added after adding the salt of the alkaline earth metal. According to some embodiments, the stabilizer is added before bubbling or pressurizing the CO2 gas and together with the addition of the salt of the alkaline earth metal. According to some embodiments, the stabilizer is added before bubbling or pressurizing the CO2 gas and after adding the salt of the alkaline earth metal. According to some embodiments, the stabilizer is added after bubbling or pressurizing the CO2 gas and after adding the salt of the alkaline earth metal.

[0059] According to some embodiments, the stabilizer is added after bubbling or pressurizing the CO2 gas and together with the addition of the salt of the alkaline earth metal.

[0060] According to some embodiments, the method comprises: (i) Dissolve an alkali in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) Bubble or pressurize CO2 gas into the solution obtained in step (i), and then add the salt of the alkaline earth metal; and (iii) Collect the obtained amorphous alkaline earth metal carbonate precipitate.

[0061] In some embodiments, the method includes adding a stabilizer before bubbling or pressurizing CO2 gas into the solution obtained in step (i). In some embodiments, the method includes adding a stabilizer after adding a salt of an alkaline earth metal. In some embodiments, the method includes adding a stabilizer before bubbling or pressurizing CO2 gas into the solution obtained in step (i) and after adding a salt of an alkaline earth metal.

[0062] According to some embodiments, the method includes: (i) dissolving an alkali in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) adding a salt of an alkaline earth metal to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas into the solution, (iii) collecting the resulting amorphous alkaline earth metal carbonate precipitate.

[0063] According to some embodiments, the method includes adding a stabilizer together with the addition of a salt of an alkaline earth metal. According to some embodiments, the method includes adding a stabilizer before bubbling or pressurizing CO2 gas into the solution obtained in step (i). According to some embodiments, the method includes adding a stabilizer together with the addition of a salt of an alkaline earth metal and further before bubbling or pressurizing CO2.

[0064] According to some embodiments, the stabilizers added in several stages are the same or different. According to some embodiments, the stabilizer added before bubbling or pressurizing CO2 gas into the solution obtained in step (i) and the stabilizer added after adding a salt of an alkaline earth metal are the same stabilizer. According to other embodiments, the stabilizers added in different stages are different stabilizers.

[0065] According to some embodiments, the stabilizer added together with the addition of a salt of an alkaline earth metal and the stabilizer further added before bubbling or pressurizing CO2 are the same stabilizer. According to other embodiments, the stabilizers added in different stages are different stabilizers.

[0066] As contemplated by the present invention, the terms "bubbling CO2" and "pressurizing CO2" can be used interchangeably and refer to incorporating CO2 into an aqueous solution. The process can be carried out as known in the art. Bubbling can be carried out at a constant pressure or a varying pressure, at a constant rate or a varying rate.

[0067] According to some embodiments, the method includes, as a first step, dissolving an alkali and a stabilizer in an aqueous solution. Thus, according to some embodiments, the present invention provides a method for preparing a stabilized amorphous alkaline earth metal carbonate, the method including: (i) Dissolve an alkali and a stabilizer in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) Bubble or pressurize CO2 gas into the solution obtained in step (i), and then add a salt of an alkaline earth metal and optionally a stabilizer to the solution; or add the salt of an alkaline earth metal to the solution obtained in step (i), and then bubble or pressurize CO2 gas into the solution and optionally add a stabilizer, thereby precipitating a stabilized amorphous alkaline earth metal carbonate; (iii) Optionally add a stabilizer to the solution obtained in step (ii), and (iv) Collect the resulting stabilized amorphous alkaline earth metal carbonate, wherein CO2 is continuously introduced into the solution during step (ii) and step (iii) (if present), and the stabilizers in step (i) and step (ii) and / or step (iii) (if present) are the same or different.

[0068] According to some embodiments, step (ii) includes bubbling or pressurizing CO2 gas into the solution obtained in step (i), and then adding a salt of an alkaline earth metal. Thus, according to some embodiments, the method comprises the following steps: (i) Dissolve an alkali and a stabilizer in an aqueous solution; (ii) Bubble or pressurize CO2 gas into the solution obtained in step (i), and then add a salt of an alkaline earth metal and optionally a stabilizer to the solution; (iii) Optionally add a stabilizer to the solution obtained in step (ii), and (iv) Collect the resulting stabilized amorphous alkaline earth metal carbonate.

[0069] According to another embodiment, step (ii) includes adding a salt of an alkaline earth metal to the solution obtained in step (i), and then bubbling or pressurizing CO2 gas into the solution. Thus, according to some embodiments, the method comprises the following steps: (i) Dissolve an alkali and a stabilizer in an aqueous solution; (ii) Add a salt of an alkaline earth metal and optionally a stabilizer to the solution obtained in step (i), and then bubble or pressurize CO2 gas; (iii) Optionally add a stabilizer to the solution obtained in step (ii), and (iv) Collect the resulting stabilized amorphous alkaline earth metal carbonate.

[0070] In some embodiments, the present invention provides a method for preparing a stabilized amorphous alkaline earth metal carbonate, the method comprising: (a) Dissolve the base in an aqueous solution; (b) Dissolve the stabilizer in the solution obtained in step (a), and then bubble or pressurize CO2 gas into the solution, wherein dissolving the stabilizer and initiating CO2 introduction by bubbling or pressurizing are carried out in either order; (c) Add a salt of an alkaline earth metal and optionally a stabilizer to the solution obtained in step (b), thereby precipitating ACC; and (d) Optionally add a stabilizer to the solution obtained in step (c), wherein CO2 is continuously introduced into the solution during steps (b) and (c), and the stabilizers in step (b) and steps (c) and (d) (if added) are the same or different.

[0071] According to some embodiments, the method of the present invention allows for the fixation of CO2 gas. Thus, in any one of the embodiments of the present invention, the term "method for preparing stabilized amorphous alkaline earth metal carbonate" may be replaced by the term "method for fixing CO2".

[0072] According to some embodiments, the present invention provides a method for fixing CO2, the method comprising: (a) Dissolve the base in an aqueous solution; <00003??>(b) Dissolve the stabilizer in the solution obtained in step (a), and then bubble or pressurize CO2 gas into the solution, wherein dissolving the stabilizer and initiating CO2 introduction by bubbling or pressurizing are carried out in either order; (c) Add a salt of an alkaline earth metal and optionally a stabilizer to the solution obtained in step (b), thereby precipitating stabilized amorphous alkaline earth metal carbonate; and (d) Optionally add a stabilizer to the solution obtained in step (c), wherein CO2 is continuously introduced into the solution during steps (b) and (c), and the stabilizers in step (b) and steps (c) and (d) (if added) are the same or different.

[0073] According to some embodiments, the present invention provides a method for fixing CO2, the method comprising: (i) Dissolve the base and the stabilizer in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) Bubble or pressurize CO2 gas into the solution obtained in step (i), then add a salt of an alkaline earth metal and optionally add a stabilizer to the solution; or add a salt of an alkaline earth metal to the solution obtained in step (i), then bubble or pressurize CO2 gas into the solution and optionally add a stabilizer, It should be noted that there seems to be an error in the original text where the number in is incorrect. It is assumed to be a typo and should be as per the sequence.Thereby fixing CO2 and precipitating a stabilized alkaline earth metal carbonate; (iii) Optionally adding a stabilizer to the solution obtained in step (ii), and (iv) Collecting the resulting stabilized amorphous alkaline earth metal carbonate, wherein CO2 is continuously introduced into the solution during step (ii) and step (iii) (if present), and the stabilizer in step (i) and step (ii) and / or step (iii) (if present) is the same or different.

[0074] According to some embodiments, the pH of the solution obtained after adding the base in step (i) is equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11 or equal to or higher than 12. According to some embodiments, the pH of the solution obtained in step (i) is equal to or higher than 9. According to some embodiments, the pH of the solution obtained in step (i) is equal to or higher than 10. According to some embodiments, the pH of the solution obtained in step (i) is equal to or higher than 11. According to some embodiments, the pH of the solution obtained in step (i) is equal to or higher than 12. According to some embodiments, the pH of the solution obtained in step (i) is from 8 to 13. According to some embodiments, the pH of the solution obtained in step (i) is from 9 to 13. According to some embodiments, the pH of the solution obtained in step (i) is from 10 to 13. According to some embodiments, the pH of the solution obtained in step (i) is from 1 to 13. According to some embodiments, the pH of the solution obtained in step (i) is from 8 to 12. According to some embodiments, the pH of the solution obtained in step (i) is from 9 to 12. According to some embodiments, the pH of the solution obtained in step (i) is from 10 to 12. According to some embodiments, the pH of the solution obtained in step (i) is from 9 to 11. According to some embodiments, the pH of the solution obtained in step (i) is from 10 to 12. According to some embodiments, the pH of the solution obtained in step (i) is from 9.5 to 10.5 or about 10.

[0075] According to some embodiments, the precipitation of the alkaline earth metal carbonate is completed within 2 minutes. According to some embodiments, the precipitation of the alkaline earth metal carbonate is completed within 3 minutes. According to some embodiments, the precipitation of the alkaline earth metal carbonate is completed within 1.5 minutes.

[0076] According to some embodiments, the method includes adding a stabilizer in step (ii). Thus, according to some embodiments, step (ii) includes bubbling or pressurizing CO2 gas into the solution obtained in step (i), followed by adding a salt of an alkaline earth metal and adding a stabilizer. According to other embodiments, step (ii) includes adding a salt of an alkaline earth metal and a stabilizer to the solution obtained in step (i), followed by bubbling or pressurizing CO2 gas. According to some embodiments, the stabilizer added in step (i) and step (ii) is the same stabilizer. According to some embodiments, the stabilizer added in step (i) and step (ii) is a different stabilizer.

[0077] According to some embodiments, the method includes adding a stabilizer only in steps (i) and (ii). According to some embodiments, the method includes adding a stabilizer in step (iii). According to some embodiments, the method includes adding a stabilizer only in steps (i) and (iii). According to some embodiments, the stabilizer added in step (i) and step (iii) is the same stabilizer. According to some embodiments, the stabilizer added in step (i) and step (iii) is a different stabilizer. According to some embodiments, the method includes adding a stabilizer in steps (ii) and (iii). According to some embodiments, when a stabilizer is added in multiple stages or steps, the stabilizer can be different in each step. According to other embodiments, the stabilizer in all steps can be the same stabilizer.

[0078] According to any of the above embodiments, the method may include a step of degassing the aqueous solution before starting the process of preparing the stabilized amorphous alkaline earth metal carbonate or fixing CO2. The degassing can be carried out using any known technique. According to some embodiments, the degassing is carried out, for example, by bubbling CO2 gas into the aqueous solution before adding the base.

[0079] According to some embodiments, the method of the present invention is carried out in the form of a batch reaction. According to some embodiments, the method is carried out in the form of a series of batches. Thus, according to any of the above embodiments, the method is a batch method.

[0080] According to some embodiments, the method is carried out in the form of a continuous process. Thus, according to some embodiments of the present invention, the present invention provides a method for preparing a stabilized amorphous alkaline earth metal carbonate, the method comprising: providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding an alkali, at least one stabilizer, and an alkaline earth metal to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) continuously collecting the resulting stabilized amorphous alkaline earth metal carbonate precipitate, wherein the pH is constantly maintained equal to or higher than 8 throughout the process. According to some embodiments, the pH of the provided solution is equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12, and is maintained at a value between 8 and 12 throughout the process. According to some embodiments, the pH of the provided solution is from 8 to 13, and the pH is maintained at a value between 8 and 13 throughout the process. According to some embodiments, the pH of the provided solution is from 8 to 13. According to some embodiments, the pH of the provided solution is from 9 to 13. According to some embodiments, the pH of the provided solution is from 10 to 13. According to some embodiments, the pH of the provided solution is from 1 to 13. According to some embodiments, the pH of the provided solution is from 8 to 12. According to some embodiments, the pH of the provided solution is from 9 to 12. According to some embodiments, the pH of the provided solution is from 10 to 12. According to some embodiments, the pH of the provided solution is from 9 to 11. According to some embodiments, the pH of the provided solution is from 10 to 12. According to some embodiments, the pH of the provided solution is from 9.5 to 10.5 or about 10. According to some embodiments, the pH is maintained at a value from 8 to 13 throughout the process. According to some embodiments, the pH is maintained at a value from 9 to 13 throughout the process. According to some embodiments, the pH is maintained at a value from 10 to 13 throughout the process. According to some embodiments, the pH is maintained at a value from 1 to 13 throughout the process. According to some embodiments, the pH is maintained at a value from 8 to 12 throughout the process. According to some embodiments, the pH is maintained at a value from 9 to 12 throughout the process. According to some embodiments, the pH is maintained at a value from 10 to 12 throughout the process. According to some embodiments, the pH is maintained at a value from 9 to 11 throughout the process. According to some embodiments, the pH is maintained at a value from 10 to 12 throughout the process. According to some embodiments, the pH is maintained at a value from 9.5 to 10.5 or about 10 throughout the process.

[0081] The term "amorphous alkaline earth metal carbonate" refers to the amorphous form of the carbonate of any alkaline earth metal. Non-limiting examples of alkaline earth metals are calcium and magnesium. The terms "amorphous alkaline earth metal carbonate" and "stabilized amorphous alkaline earth metal carbonate" are used interchangeably herein. The terms "amorphous calcium carbonate", "ACC", "stable ACC", and "stabilized ACC" are used interchangeably herein and refer to the amorphous form of calcium carbonate. The terms "amorphous magnesium carbonate", "AMC", "stable AMC", and "stabilized AMC" are used interchangeably herein and refer to the amorphous form of magnesium carbonate. The term AMC does not exclude the presence of Mg-OH functional groups. As used herein, the term "stable" indicates that the calcium carbonate remains in the amorphous form in a solid form with less than or about 30% crystalline calcium carbonate for a long period of time, such as for at least about 7 days. According to any of the above embodiments, the composition is stable for at least 7 days. According to some embodiments, the composition is stable for at least 1 month. According to other embodiments, the composition is stable for at least 3 months. According to further embodiments, the composition is stable for 6 months. According to certain embodiments, the composition is stable for at least 1 year. According to specific embodiments, the composition is stable for at least 2 years. According to some embodiments, ACC is stable in aqueous solution in the amorphous form for at least 7 days, at least 1 month, at least 3 months, or 6 months.

[0082] In most cases, the resulting ACC or AMC contains from 1 wt% to 20 wt% adsorbed water and retains its stability in the presence of a stabilizer and upon further storage under dry conditions. According to some embodiments, the resulting ACC contains from 5 wt% to 15 wt% or about 10 wt% adsorbed water. As can be seen from the examples, the ACC powder obtained in the examples contains about 6 wt% to 10 wt% water when formulated. In terms of calcium content, it means that the calcium content in the ACC is in the actual range of 28 wt% to 38 wt% of its composition. According to some embodiments, the resulting stabilized ACC contains from 30 wt% to 38 wt%, from 32 wt% to 36 wt%, or about 34 wt% calcium.

[0083] Small amounts of water precursors are also present in the form of bicarbonate anions [Ca-O-(C=O)-OH] and carbonate anions [Ca-O-(C=O)-O - found in the disordered molecular network of ACC. At high temperatures and as part of the crystallization process, these substances are converted to fully bound carbonates through a condensation reaction, which results in the release of water molecules.

[0084] In the case of amorphous magnesium carbonate, the presence of even more complex waters and water precursors can be expected, since it is well known that the molecular structures of most of the eight defined phases of even crystalline magnesium carbonate are "hydrates" (i.e., contain water molecules complexed by strong bonding to the Mg element), "basic" (i.e., contain Mg-OH), or both. In addition, the presence of various bicarbonate species has been detected in crystalline magnesium carbonate phases, such as the most common nesquehonite phase, previously defined as MgCO3 . 3H2O.

[0085] According to some embodiments, the alkaline earth metal salt is a water-soluble salt of an alkaline earth metal. According to some embodiments, the alkaline earth metal salt is selected from the halides, nitrates, and sulfates of the metal and their hydrates. According to some embodiments, the alkaline earth metal is selected from calcium and magnesium. According to some embodiments, the alkaline earth metal salt is selected from calcium halides, magnesium halides, calcium nitrate, magnesium nitrate, and magnesium sulfate. According to some embodiments, the halide is selected from chlorides and bromides. According to some embodiments, the alkaline earth metal salt is selected from calcium chloride, calcium bromide, calcium nitrate, magnesium chloride, magnesium sulfate, magnesium nitrate, and combinations thereof. According to some embodiments, the alkaline earth metal salt is calcium chloride. According to some embodiments, the alkaline earth metal salt is calcium sulfate. According to some embodiments, the alkaline earth metal salt is magnesium chloride. According to some embodiments, the alkaline earth metal salt is magnesium sulfate. According to some embodiments, the alkaline earth metal salt can be water-insoluble, such as CaO, Ca(OH)2, MgO, Mg(OH)2. In another embodiment, the alkaline earth metal salt is a combination of calcium chloride and magnesium sulfate.

[0086] According to some embodiments, the alkaline earth metal salt is calcium chloride. According to some embodiments, calcium chloride can be in any known hydrated state, i.e., CaCl2·nH2O for multiple values of n = 0, 1, 2, 4, or 6, such as anhydrous, monohydrate, or dihydrate. According to some embodiments, calcium chloride is calcium chloride hydrate.

[0087] According to some embodiments, the alkaline earth metal salt is magnesium sulfate. According to some embodiments, magnesium sulfate can be in any known hydrated state. Magnesium sulfate can be in the form of a hydrate MgSO4·nH2O for multiple values of n between 1 and 11. According to some embodiments, magnesium sulfate can be in anhydrous or heptahydrate form. According to some embodiments, magnesium sulfate is magnesium sulfate heptahydrate.

[0088] According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.02 mole (M) to 1 mole (M). According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.02 M to 0.95 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.03 M to 0.9 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.06 M to 0.86 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.1 M to 0.85 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.15 M to 0.85 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.2 M to 0.85 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.25 M to 0.85 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.3 M to 0.80 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.34 M to 0.85 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.2 M to 0.6 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.3 M to 0.5 M. According to some embodiments, the method includes adding a salt of an alkaline earth metal from 0.3 M to 0.4 M. According to some embodiments, the salt of the alkaline earth metal is calcium chloride. According to some embodiments, the salt of the alkaline earth metal is magnesium sulfate.

[0089] According to some embodiments, the method includes adding calcium chloride from 0.1 M to 0.85 M. According to some embodiments, the method includes adding calcium chloride from 0.2 M to 0.85 M. According to some embodiments, the method includes adding calcium chloride from 0.3 M to 0.8 M. According to some embodiments, the method includes adding calcium chloride from 0.3 M to 0.7 M. According to some embodiments, the method includes adding calcium chloride from 0.3 M to 0.6 M. According to some embodiments, the method includes adding calcium chloride from 0.3 M to 0.5 M. According to some embodiments, the method includes adding approximately 0.34 M of calcium chloride. According to some embodiments, the calcium chloride can be in any known hydrated state, such as anhydrous, monohydrate, or dihydrate.

[0090] According to some embodiments, the method includes adding magnesium sulfate from 0.1 M to 0.85 M. According to some embodiments, the method includes adding magnesium sulfate from 0.2 M to 1 M. According to some embodiments, the method includes adding magnesium sulfate from 0.3 M to 0.9 M. According to some embodiments, the method includes adding magnesium sulfate from 0.35 M to 0.8 M. According to some embodiments, the method includes adding magnesium sulfate from 0.4 M to 0.6 M. According to some embodiments, the method includes adding magnesium sulfate from 0.4 M to 0.5 M. According to some embodiments, the method includes adding about 0.46 M of magnesium sulfate. According to some embodiments, magnesium sulfate may be in anhydrous or heptahydrate form. According to some embodiments, magnesium sulfate is magnesium sulfate heptahydrate.

[0091] According to any of the above embodiments, when referring to a continuous method for preparing a stabilized amorphous alkaline earth metal carbonate, the term "adding a compound at concentration X" or any equivalent of this phrase encompasses continuous addition and maintenance of said concentration.

[0092] According to some embodiments, the base is selected from hydroxides of alkali metals, ammonia, or ammonium hydroxide. According to some embodiments, the base is a hydroxide of an alkali metal. According to some embodiments, the alkali metal is selected from sodium and potassium. According to one embodiment, the hydroxide of the alkali metal is sodium hydroxide (NaOH). According to one embodiment, the base is ammonia. According to one embodiment, the base is ammonium hydroxide.

[0093] According to some embodiments, the amount of base added in step (i) corresponds to at least 2 molar equivalents of the amount of the alkaline earth metal salt. According to some embodiments, the amount of base added in step (i) corresponds to at least 3 molar equivalents of the amount of the alkaline earth metal salt. According to some embodiments, the amount of a base such as NaOH, ammonia, or ammonium hydroxide corresponds to at least 2 molar equivalents or at least 3 molar equivalents of the alkaline earth metal added to the reaction. According to some embodiments, the concentration of a base such as NaOH or ammonium hydroxide is 2, 2.5, 3, 3.5, 4, 4.5, or 5 molar equivalents of the alkaline earth metal added to the reaction. According to some embodiments, the concentration of the base is constantly maintained at from 2 molar equivalents to 5 molar equivalents of the alkaline earth metal by continuously adding the base to the reaction mixture.

[0094] According to some embodiments, the amount / concentration of NaOH added in step (i) corresponds to at least 2 molar equivalents or at least 3 molar equivalents of the CaCl2 added. According to some embodiments, the amount / concentration of NH4OH added in step (i) corresponds to at least 2 molar equivalents or at least 3 molar equivalents of the CaCl2 added.

[0095] According to some embodiments, the amount / concentration of NaOH in step (i) corresponds to at least 2 molar equivalents or at least 3 molar equivalents of the added MgSO4. According to some embodiments, the amount / concentration of NH4OH in step (i) corresponds to at least 2 molar equivalents or at least 3 molar equivalents of the added MgSO4. According to some embodiments, the base is added continuously or batchwise via the solid phase, solution phase, or gas phase throughout the process. According to some embodiments, the concentration of the base, such as NaOH or NH4OH, remains constant and corresponds to at least 2 molar equivalents of the alkaline earth metal salt, such as CaCl2 or MgSO4.

[0096] According to any of the above embodiments, ACC is stabilized by at least one stabilizer. The terms "stabilizing agent" and "stabilizer" are used interchangeably herein and refer to any molecule, ion, or substance that helps to keep calcium carbonate in the amorphous state during ACC production, formulation, and / or storage. According to the teachings of the present invention, ACC acts as an active agent that confers improved locomotor and muscle performance. According to the teachings of the present invention, any stabilized ACC can be used. Any compound that can stabilize ACC in its amorphous form is suitable for the practice of the present invention.

[0097] ACC stabilizer The stabilizer can comprise a molecule having one or more functional groups selected from, but not limited to, hydroxyl groups, carboxyl groups, ester groups, amine groups, phosphino groups, phosphonyl groups, phosphoric acid / phosphate / phosphonate groups, sulfonyl groups, sulfate ester / salt groups, or sulfino groups. Compounds having hydroxyl groups in combination with hydroxides optionally also have other functionalities, such as carboxyl groups, etc., but the hydroxyl groups are not esterified.

[0098] According to some embodiments, the stabilizer has low toxicity or no toxicity to mammalian cells or organisms and particularly to humans. According to some embodiments, the stabilizer is of food grade, nutraceutical grade, or pharmaceutical grade.

[0099] In certain embodiments, the ACC stabilizer is independently, upon each occurrence, an organic acid, a phosphorylated, phosphonated, sulfated, or sulfonated organic compound, a phosphate or sulfate ester of a hydroxycarboxylic acid, an organic amine compound, an organic compound containing a hydroxy group, an organic phosphorus compound or its salt, a phosphorylated amino acid and its derivatives, a bisphosphonic acid / bisphosphonate / bisphosphinate compound, an organic phosphoric acid / organophosphoric acid ester / organophosphate compound, an organic phosphonic acid / organophosphonic acid ester / organophosphonate compound, an inorganic phosphorous acid, an organic compound having multiple functional groups as defined above, an inorganic phosphoric acid / phosphate ester / phosphate and polyphosphoric acid / polyphosphate ester / polyphosphate compound, an organic compound having a polyphosphoric acid / polyphosphate ester / polyphosphate chain, an organic surfactant, a biologically essential inorganic ion, its salt, or any combination thereof.

[0100] According to some embodiments, the stabilizer is an organic acid or its salt. According to certain embodiments, the organic acid is selected from ascorbic acid, citric acid, lactic acid, acetic acid, oxalic acid, malonic acid, glutaconic acid, succinic acid, maleic acid, lactic acid, aconitic acid, or its salt, and optionally includes a compound having at least two carboxyl groups and a molecular weight not greater than 250 g / mol, such as citric acid, tartaric acid, malic acid, etc. According to a specific embodiment, the stabilizer is citric acid or citrate.

[0101] In another embodiment, the phosphate ester of the hydroxycarboxylic acid is phosphoenolpyruvate. In another embodiment, the phosphate or sulfate ester of the hydroxycarboxylic acid includes an amino acid. Examples of such esters are phosphoserine, phosphothreonine, sulfoserine, sulfothreonine, and phosphocreatine.

[0102] The compound having a hydroxy group in combination with a hydroxide may include, for example, monosaccharides, disaccharides, trisaccharides, oligosaccharides, and polysaccharides such as sucrose or other polyols such as glycerol. The compound having a hydroxy group may also include hydroxy acids such as citric acid, tartaric acid, malic acid, etc., or amino acids having a hydroxy group such as serine or threonine and their salts. Each possibility represents a separate embodiment of the present invention.

[0103] Some specific non-limiting examples of such ACC stabilizers include phytic acid, citric acid and its salts, disodium hydrogen pyrophosphate, adenosine-5'-monophosphate (AMP) sodium salt, adenosine-5'-diphosphate (ADP) sodium salt, and adenosine-5'-triphosphate (ATP) disodium hydrate, phosphoserine, phosphorylated amino acids, food-grade surfactants, sodium stearoyl lactate, and combinations thereof.

[0104] According to some embodiments, the stabilizer includes at least one component selected from phosphates or sulfates of hydroxycarboxylic acids, such as phosphoenolpyruvate, phosphoserine, phosphothreonine, sulfo-serine or sulfo-threonine; and organic compounds having hydroxyl groups selected from monosaccharides, disaccharides, trisaccharides, oligosaccharides and polysaccharides, such as sucrose, mannose, glucose.

[0105] The compound having a hydroxyl group may also include at least one alkaline hydroxide, such as sodium hydroxide, potassium hydroxide and the like. Phosphorylated acids may be present in oligopeptides and polypeptides. In other embodiments of the present invention, the stabilizer is an organic acid selected from the following: monocarboxylic acids or polycarboxylic acids such as dicarboxylic acids or tricarboxylic acids. Each possibility represents a separate embodiment of the present invention. The organic acid may be defined as above.

[0106] In some embodiments of the present invention, the ACC stabilizer is selected from phosphorylated amino acids, polyols and combinations thereof. In some embodiments, the stabilized ACC contains a phosphorylated compound as a stabilizer, wherein phosphorylation is carried out on the hydroxyl groups of the organic compound. In some embodiments, the stabilized ACC contains a stabilizer selected from the group consisting of citric acid, phosphoserine, phosphothreonine and combinations thereof. Non-limiting examples of stabilizers containing phosphate groups, phosphite groups, phosphonate groups and their salts or esters include phytic acid, dimethyl phosphate, trimethyl phosphate, sodium pyrophosphate, tetraethyl pyrophosphate, ribulose bisphosphate, etidronic acid and other pharmaceutical bisphosphonic acids / bisphosphonates / bisphosphonates, 3-phosphoglycerate, 3-phosphoglyceraldehyde, sodium 1-deoxy-D-xylulose-5-phosphate, diethylenetriamine penta(methylphosphonic acid), nitrilotri(methylphosphonic acid), sodium 5-phospho-D-ribose-1-diphosphate, sodium adenosine-5'-diphosphate, adenosine-5'-triphosphate disodium hydrate, α-D-galactosamine-1-phosphate, trisodium 2-phospho-L-ascorbate, dipotassium α-D-galactose-1-phosphate pentahydrate, α-D-galactosamine-1-phosphate, O-phosphoethanolamine, disodium hydrate, pentasodium salt of 2,3-diphospho-D-glyceric acid, sodium salt hydrate of phospho(enol)pyruvate, D-glyceraldehyde-3-phosphate, lithium salt of sn-glycerol-3-phosphate, disodium salt of D-(-)-3-phosphoglyceric acid, sodium salt of D-glucose-6-phosphate, phosphatidic acid, sodium ibandronate, phosphonoacetic acid, DL-2-amino-3-phosphonopropionic acid or combinations thereof.

[0107] In some embodiments, the stabilizer may be biologically essential inorganic ions, which include especially Na, K, Mg, Zn, Fe, P, S, N; P or S in the phase of oxides; or N as ammonia or nitro groups.

[0108] Stabilized ACC can be stabilized by more than one stabilizer, such as two, three or more stabilizers. The stabilizer can be added during the synthesis and precipitation of the ACC primary particles, and they are defined as "internal stabilizers". The stabilizer can be added after synthesis and incorporated into the outer surface of the particles. They are defined as "external stabilizers". In some embodiments where both internal and external stabilizers are used, the internal stabilizer and the external stabilizer are similar. In other embodiments, the internal stabilizer and the external stabilizer are different stabilizers. The internal and external stabilizers can be independently defined as above and can each be a combination of more than one type of stabilizer.

[0109] Stable ACC can contain more than two stabilizers, wherein one or more stabilizers are added to the ACC during the formation and precipitation of the ACC.

[0110] According to some embodiments, the stabilizer is selected from the group consisting of: polyphosphoric acid / polyphosphate / polyphosphonate, polyphosphonic acid / polyphosphonate / polyphosphonate, bisphosphonic acid / bisphosphonate / bisphosphonate, phosphorylated amino acids, citric acid, its salts and any combination thereof. In some embodiments, more than one stabilizer is added, such as two, three or four stabilizers.

[0111] According to one embodiment, ACC is stabilized by a combination of phosphoserine and citric acid. According to another embodiment, ACC is stabilized by a combination of triphosphoric acid / triphosphate / triphosphonate and citric acid.

[0112] According to some embodiments, the stabilizer is polyphosphoric acid / polyphosphate ester or a pharmaceutically acceptable salt thereof. According to some embodiments, the polyphosphoric acid / polyphosphate ester / polyphosphate is a physiologically compatible water-soluble polyphosphate selected from the group consisting of sodium cation salts, potassium cation salts, and any other necessary cation salts of polyphosphoric acid. In one embodiment, the polyphosphoric acid / polyphosphate ester / polyphosphate is an organic or inorganic polyphosphoric acid / polyphosphate ester / polyphosphate. As used herein, the term "polyphosphoric acid / polyphosphate ester / polyphosphate" refers to (1) a polymer non-hydrate of PO4 or (2) a phosphorylated organic compound containing more than 1 phosphorylated group bonded via a C-O-P (ether) bond. An example of a type 2 polyphosphoric acid / polyphosphate ester / polyphosphate is phytic acid or a salt thereof, which contains 6 phosphorylated groups. According to some embodiments, the polyphosphoric acid / polyphosphate ester / polyphosphate is a physiologically compatible water-soluble polyphosphate selected from the group consisting of sodium polyphosphate and potassium polyphosphate. In some embodiments, the polyphosphoric acid / polyphosphate ester / polyphosphate is an inorganic polyphosphoric acid / polyphosphate ester or a pharmaceutically acceptable salt thereof. Non-limiting examples of such salts are Na, K, Mg, Mn, and Zn. According to some embodiments, the polyphosphoric acid / polyphosphate ester / polyphosphate such as an inorganic polyphosphoric acid / polyphosphate ester / polyphosphate contains 2 to 10 phosphate / phosphate ester / phosphate groups, such as 2, 3, 4, 5, 6, 7, 8, 9, or 10 phosphate / phosphate ester / phosphate groups. According to some embodiments, the inorganic polyphosphoric acid / polyphosphate ester / polyphosphate is selected from pyrophosphoric acid / pyrophosphate ester / pyrophosphate, triphosphoric acid / triphosphate ester / triphosphate, and hexametaphosphoric acid / hexametaphosphate ester / hexametaphosphate. According to one embodiment, the stabilizer is pyrophosphoric acid / pyrophosphate ester or a pharmaceutically acceptable salt thereof, such as sodium pyrophosphate. According to another embodiment, the stabilizer is triphosphoric acid / triphosphate ester (tripolyphosphoric acid / tripolyphosphate ester) or a pharmaceutically acceptable salt thereof, such as sodium triphosphate. The terms "triphosphoric acid / triphosphate ester / triphosphate" and "tripolyphosphoric acid / tripolyphosphate ester / tripolyphosphate" are used interchangeably herein. According to additional embodiments, the stabilizer is hexametaphosphoric acid / hexametaphosphate ester or a pharmaceutically acceptable salt thereof, such as sodium hexametaphosphate.

[0113] According to some embodiments, the stabilizer is a polyphosphoric acid / polyphosphate ester / polyphosphate such as diphosphoric acid / diphosphate ester or tetraphosphoric acid / tetraphosphate ester or a pharmaceutically acceptable salt thereof. Non-limiting examples of the salts are Na, K, Mg, Mn, and Zn.

[0114] As used herein, the term "bisphosphonic acid / bisphosphonate / bisphosphinate" refers to an organic compound having two phosphonic acid (PO(OH)2) groups. The term also encompasses compounds having a PO3-organic-PO3 backbone. Most typically, a series of bisphosphonic acids / bisphosphonates / bisphosphinates are used as drugs for treating osteoporosis. According to some embodiments, the bisphosphonic acid / bisphosphonate / bisphosphinate is selected from the group consisting of etidronic acid, zoledronic acid, methylene diphosphonic acid, alendronic acid, and pharmaceutically acceptable salts thereof. According to some embodiments, the stabilizer is etidronic acid or a pharmaceutically acceptable salt thereof. According to another embodiment, the stabilizer is zoledronic acid or a pharmaceutically acceptable salt thereof. According to a further embodiment, the stabilizer is methylene diphosphonic acid or a pharmaceutically acceptable salt thereof. According to certain embodiments, the stabilizer is alendronic acid or a pharmaceutically acceptable salt thereof.

[0115] According to certain embodiments, the stabilizer is a phosphorylated amino acid. According to one embodiment, the phosphorylated amino acid is phosphoserine. According to another embodiment, the phosphorylated amino acid is phosphothreonine.

[0116] According to certain embodiments, the stabilizer is phytic acid or a salt thereof.

[0117] According to some embodiments, the ACC composition comprises a combination of the stabilizers disclosed above.

[0118] According to some embodiments, the stabilizer is an inorganic polyphosphoric acid / polyphosphonate / polyphosphate or bisphosphonic acid / bisphosphonate / bisphosphinate as defined above, and the molar ratio between the P atoms of the stabilizer and the Ca atoms of the ACC (P:Ca molar ratio) is from about 1:90 to 1:1. In one embodiment, the P:Ca molar ratio is from about 1:40 to about 1:1. In a further embodiment, the P:Ca molar ratio is from about 1:35 to about 1:2. In certain embodiments, the P:Ca molar ratio is from about 1:30 to about 1:3. In certain embodiments, the P:Ca molar ratio is from about 1:28 to about 1:3. In other embodiments, the P:Ca molar ratio is from about 1:25 to about 1:4. In a further embodiment, the P:Ca molar ratio is from about 1:20 to about 1:5. In another embodiment, the P:Ca molar ratio is from about 1:20 to about 1:6. In a particular embodiment, the P:Ca molar ratio is from about 1:15 to about 1:5. In another particular embodiment, the P:Ca molar ratio is from about 1:25 to about 1:5. According to some embodiments, such inorganic polyphosphoric acid / polyphosphonate / polyphosphate is pyrophosphoric acid / pyrophosphate, triphosphoric acid / triphosphate, hexametaphosphoric acid / hexametaphosphate, or a pharmaceutically acceptable salt thereof. According to another embodiment, the bisphosphonic acid / bisphosphonate / bisphosphinate is alendronic acid, etidronic acid, zoledronic acid, or methylene diphosphonic acid, and the P:Ca molar ratio is as defined above.

[0119] According to some embodiments, the calcium content (Ca content) of such a stabilizer-containing composition is about 1 wt% to about 39 wt%, about 5 wt% to about 39 wt%, about 10 wt% to about 39 wt%, about 15 wt% to about 39 wt%, about 20 wt% to about 38 wt%, about 25 wt% to about 38 wt%, or about 30 wt% to about 38 wt% of the dry ACC particles. The terms "Ca content" and "calcium content" are used interchangeably herein and refer to the calcium content of ACC in the final composition.

[0120] In certain embodiments, the P:Ca molar ratio is about 1:40 to about 1:1, and the Ca content is about 20 wt% to about 39 wt%. In some embodiments, the molar ratio is 1:28 to about 1:3, and the Ca content is about 30 wt% to about 38 wt% of the dry ACC particles. In another embodiment, the molar ratio is 1:25 to about 1:5, and the Ca content is about 30 wt% to about 36 wt% of the dry ACC particles.

[0121] According to some embodiments, the stabilizer is an inorganic polyphosphoric acid / polyphosphate / polyphosphonate or bisphosphonic acid / bisphosphonate / bisphosphonate as defined above, and the molar ratio between the P atom of the stabilizer and the Mg atom of amorphous magnesium carbonate (AMC) (P:Mg molar ratio) is about 1:90 to 1:1. In one embodiment, the P:Mg molar ratio is about 1:40 to about 1:1. In additional embodiments, the P:Mg molar ratio is about 1:35 to about 1:2. In certain embodiments, the P:Mg molar ratio is about 1:30 to about 1:3. In certain embodiments, the P:Mg molar ratio is about 1:28 to about 1:3. In other embodiments, the P:Mg molar ratio is about 1:25 to about 1:4. In additional embodiments, the P:Mg molar ratio is about 1:20 to about 1:5. In another embodiment, the P:Mg molar ratio is about 1:20 to about 1:6. In a particular embodiment, the P:Mg molar ratio is about 1:15 to about 1:5. In another particular embodiment, the P:Mg molar ratio is about 1:25 to about 1:5. According to some embodiments, such inorganic polyphosphoric acid / polyphosphate / polyphosphonate is pyrophosphoric acid / pyrophosphate, triphosphoric acid / triphosphate, hexametaphosphoric acid / hexametaphosphate, or a pharmaceutically acceptable salt thereof. According to another embodiment, the bisphosphonic acid / bisphosphonate / bisphosphonate is alendronic acid, etidronic acid, zoledronic acid, or methylenephosphonic acid, and the P:Mg molar ratio is as defined above.

[0122] According to some embodiments, the magnesium content (Mg content) of such a stabilizer-containing composition is about 1 wt% to about 39 wt%, about 5 wt% to about 39 wt%, about 10 wt% to about 39 wt%, about 15 wt% to about 39 wt%, about 20 wt% to about 38 wt%, about 25 wt% to about 38 wt%, or about 30 wt% to about 38 wt% of the dry ACC granules. The terms "Mg content" and "magnesium content" are used interchangeably herein and refer to the magnesium content of the AMC in the final composition.

[0123] In certain embodiments, the P:Mg molar ratio is about 1:40 to about 1:1, and the Ca content is about 20 wt% to about 39 wt%. In some embodiments, the molar ratio is 1:28 to about 1:3, and the Mg content is about 30 wt% to about 38 wt% of the dry ACC granules. In another embodiment, the molar ratio is 1:25 to about 1:5, and the Mg content is about 30 wt% to about 36 wt% of the dry AMC granules.

[0124] According to some embodiments, the stabilized ACC or AMC powder contains from about 1 wt% to about 18 wt%, from about 4 wt% to about 15 wt%, and from about 6 wt% to about 10 wt% of absorbed and adsorbed water. According to some embodiments, the stabilizer is polyphosphoric acid / polyphosphate / polyphosphonate or diphosphoric acid / diphosphate / diphosphonate, and the molar ratio between the P atom of the stabilizer and the Ca atom of the ACC is about 1:90 to 1:1. According to some embodiments, the stabilizer is polyphosphoric acid / polyphosphate / polyphosphonate or diphosphoric acid / diphosphate / diphosphonate, and the molar ratio between the P atom of the stabilizer and the Mg atom of the AMC is about 1:90 to 1:1.

[0125] According to some embodiments, the stabilizer is selected from the group consisting of: polyphosphoric acid / polyphosphate / polyphosphonate, phosphorylated amino acids, diphosphonic acid / diphosphate / diphosphonate, citric acid, tartaric acid, and any combination thereof. According to one embodiment, the polyphosphoric acid / polyphosphate / polyphosphonate is selected from the group consisting of triphosphoric acid / triphosphate / triphosphonate, pyrophosphoric acid / pyrophosphate / pyrophosphonate, and hexametaphosphoric acid / hexametaphosphate / hexametaphosphonate, the phosphorylated amino acid is phosphoserine or phosphothreonine, and the diphosphonic acid / diphosphate / diphosphonate is selected from the group consisting of alendronate / salt, etidronic acid, zoledronic acid, and methylene diphosphonic acid. According to some embodiments, the polyphosphoric acid / polyphosphate / polyphosphonate is inorganic polyphosphoric acid / polyphosphate / polyphosphonate.

[0126] According to one embodiment, the stabilizer is selected from the group consisting of: organic acids, phosphorylated, phosphonated, sulfated or sulfonated organic compounds, phosphate or sulfate esters of hydroxycarboxylic acids, phosphorylated amino acids, bisphosphonic acids / bisphosphonates / bisphosphates, organic polyphosphoric acids / polyphosphates / polyphosphonates, organic compounds having a hydroxyl group, derivatives thereof, proteins and any combination thereof.

[0127] According to another embodiment, the stabilizer is selected from the group consisting of: phosphoserine, adenosine triphosphate, adenosine diphosphate, phytic acid, citric acid, etidronic acid, pyrophosphoric acid / pyrophosphates / pyrophosphonates, polyphosphoric acid / polyphosphates / polyphosphonates, inorganic triphosphoric acid / triphosphates / triphosphonates, hexametaphosphoric acid / hexametaphosphates / hexametaphosphonates, ethanol and any combination thereof.

[0128] According to some embodiments, the stabilizer is selected from the group consisting of: polyphosphoric acid / polyphosphates / polyphosphonates, organic acids, phosphorylated amino acids, phosphorylated, phosphonated, sulfated or sulfonated organic compounds, phosphate or sulfate esters of hydroxycarboxylic acids, bisphosphonic acids / bisphosphonates / bisphosphates, organic polyphosphoric acids / polyphosphates / polyphosphonates, polyphosphoric acid / polyphosphates / polyphosphonates, organic compounds having a hydroxyl group, derivatives thereof, proteins and any combination thereof.

[0129] According to some embodiments, the stabilizer is selected from the group consisting of: tripolyphosphate or its salts, phosphoserine, citric acid, sodium tripolyphosphate and citric acid, adenosine triphosphate, adenosine diphosphate, phytic acid, etidronic acid, pyrophosphoric acid / pyrophosphates / pyrophosphonates, polyphosphoric acid / polyphosphates / polyphosphonates, hexametaphosphoric acid / hexametaphosphates / hexametaphosphonates, their salts, ethanol and any combination thereof.

[0130] According to some embodiments, the stabilizer in step (ii) and step (iv) is sodium tripolyphosphate.

[0131] According to some embodiments, the stabilizer added at any of the following stages is sodium tripolyphosphate: (a) before bubbling or pressurizing the CO2 gas; (b) after bubbling or pressurizing the CO2 gas; (c) before adding the salt of an alkaline earth metal, (d) together with adding the salt of an alkaline earth metal, or (e) after adding the salt of an alkaline earth metal.

[0132] According to some embodiments, the total amount / concentration of the stabilizer is jointly from 2 wt% to 15 wt% of the amount / concentration of the alkaline earth metal halide. Considering that the stabilizer can be added in more than one step, the amount / concentration of the stabilizer refers to the total amount / concentration added. Obviously, in embodiments involving the concentration of salts of alkaline earth metals, the corresponding concentration unit is used with respect to the stabilizer. According to some embodiments, the amount / concentration of the stabilizer is jointly from 3 wt% to 13 wt% of the amount / concentration of the alkaline earth metal halide. According to some embodiments, the amount / concentration of the stabilizer is jointly from 4 wt% to 15 wt% of the amount / concentration of the alkaline earth metal halide. According to some embodiments, the amount / concentration of the stabilizer is jointly from 5 wt% to 12 wt% of the amount / concentration of the alkaline earth metal halide. According to some embodiments, the amount / concentration of the stabilizer is jointly from 8 wt% to 15 wt% of the amount / concentration of the alkaline earth metal halide. According to some embodiments, the total concentration of sodium tripolyphosphate added jointly in all steps is from 2 wt% to 15 wt% of the added CaCl2. According to some embodiments, the total concentration of sodium tripolyphosphate added jointly in all steps is from 2 wt% to 15 wt% of the added MgCl2. According to some embodiments, the total concentration of sodium tripolyphosphate added jointly in all steps is from 2 wt% to 15 wt% of the added MgSO4. According to some embodiments, in the continuous process of the present invention, the stabilizer is continuously added to maintain the concentration of the salt of the alkaline earth metal at from 2 wt% to 15 wt%.

[0133] According to some embodiments, the method of the present invention is carried out at atmospheric pressure.

[0134] According to some embodiments, the method of the present invention is carried out at a CO2 pressure of from 1 bar to 60 bar.

[0135] According to any of the above embodiments, the method is carried out at ambient temperature. According to some embodiments, the method is carried out at a temperature of from 15 °C to 60 °C.

[0136] According to any of the above embodiments, the term collecting the resulting stabilized amorphous alkaline earth metal carbonate encompasses any collecting method, such as continuously collecting the precipitate. According to any of the above embodiments, collecting the resulting stabilized amorphous alkaline earth metal carbonate can be carried out by filtering the precipitate of the stabilized amorphous alkaline earth metal carbonate or by any other method common in, for example, continuously collecting solid precipitates. According to some embodiments, the method includes filtering the resulting alkaline earth metal carbonate, such as ACC or AMC. According to some embodiments, the method further includes washing the resulting ACC or AMC.

[0137] According to some embodiments, the collection also includes drying the collected precipitate. The drying can be carried out by any method, such as by air, fan, vacuum, oven, microwave oven, and combinations thereof or any other known method.

[0138] According to some embodiments, the present invention provides a method for preparing a stabilized amorphous alkaline earth metal carbonate or a method for fixing CO2, the method comprising: (i) Dissolving NaOH or NH4OH in an aqueous solution to obtain a pH of 10 or greater; (ii) Dissolving sodium tripolyphosphate in the solution obtained in step (i), and starting to bubble or pressurize CO2 gas into the solution of step (i); (iii) Adding a salt of an alkaline earth metal to the solution of step (ii), thereby precipitating an amorphous alkaline earth metal carbonate; (iv) Adding sodium tripolyphosphate to the solution of step (iii), and (v) Collecting the resulting stabilized amorphous alkaline earth metal carbonate, wherein CO2 is continuously introduced into the solution during steps (ii) and (iii), and wherein NaOH or NH4OH is added in an amount equal to 2 or more molar equivalents of the added alkaline earth metal carbonate. According to one embodiment, the alkaline earth metal carbonate is CaCl2. According to one embodiment, the alkaline earth metal carbonate is MgSO4. According to some embodiments, CaCl2 is added to a concentration of 0.2 M to 0.6 M. According to some embodiments, MgSO4 is added to a concentration of 0.3 M to 0.9 M. According to some embodiments, the reaction is carried out at ambient pressure. According to other embodiments, the reaction is carried out at a pressure from 1 bar to 60 bar or from 5 bar to 56 bar. According to some embodiments, the pH is maintained above 10 during the process. According to some embodiments, the method further includes filtering the resulting stabilized ACC or AMC. According to some embodiments, the filtering is carried out within 2 minutes from the start of adding CaCl2 or MgSO4. According to some embodiments, the method further includes washing the stabilized ACC or AMC.

[0139] According to some embodiments, the present invention provides a method for preparing an alkaline earth metal carbonate or a method for fixing CO2, the method comprising: (i) Dissolving NaOH or NH4OH in an aqueous solution to obtain a pH of 10 or greater; (ii) Dissolving sodium tripolyphosphate in the solution of step (i), and starting to bubble or pressurize CO2 into the solution; (iii) Add a salt of an alkaline earth metal and a tripolyphosphoric acid / tripolyphosphate / tripolyphosphate salt to the solution of step (ii) to precipitate an amorphous alkaline earth metal carbonate; wherein CO2 is continuously introduced into the solution during steps (ii) and (iii), and wherein NaOH or NH4OH is added in an amount equal to 2 or more molar equivalents of the added stabilized alkaline earth metal salt. According to one embodiment, the alkaline earth metal carbonate is CaCl2. According to one embodiment, the alkaline earth metal carbonate is MgSO4. According to some embodiments, CaCl2 is added to a concentration of 0.2 M to 0.6 M. According to some embodiments, MgSO4 is added to a concentration of 0.3 M to 0.9 M. According to some embodiments, the reaction is carried out at ambient pressure. According to other embodiments, the reaction is carried out at a pressure from 1 bar to 60 bar or from 5 bar to 56 bar. According to some embodiments, the pH is maintained above 10 during the process. According to some embodiments, the method further comprises filtering the stabilized ACC. According to some embodiments, the filtering is carried out within 2 minutes from the start of adding CaCl2 or MgSO4. According to some embodiments, the method further comprises washing the stabilized ACC or AMC.

[0140] According to some embodiments, the method of the present invention comprises the following steps: (i) Dissolve an alkali and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the resulting aqueous solution is 8 or greater; (ii) Bubble or pressurize CO2 gas into the solution obtained in step (i), and subsequently add CaCl2 to the solution and optionally add sodium tripolyphosphate as a stabilizer; (iii) Optionally add sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) Collect the resulting stabilized amorphous calcium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of CaCl2, and optionally wherein CaCl2 is selected from anhydrous, monohydrate, and dihydrate. According to some embodiments, the method includes adding a stabilizer in step (ii). According to some embodiments, the method includes adding a stabilizer in step (iii). According to some embodiments, the method includes adding a stabilizer in both step (ii) and step (iii). According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the preparation process. According to some embodiments, the pH is maintained at a value from 8 to 12 throughout the preparation process. According to some embodiments, the reaction is carried out at ambient pressure. According to other embodiments, the reaction is carried out at a pressure from 1 bar to 60 bar or from 5 bar to 56 bar. According to some embodiments, the pH is maintained above 10 during the process. According to some embodiments, the method further includes filtering the stabilized ACC. According to some embodiments, the filtering is carried out within 2 minutes from the addition of CaCl2. According to some embodiments, the method further includes washing the stabilized ACC. According to some embodiments, the method further includes drying the stabilized ACC.

[0141] According to some embodiments, the method of the present invention comprises the following steps: (i) dissolving a base and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the resulting aqueous solution is 8 or greater; (ii) adding CaCl2 and optionally sodium tripolyphosphate as a stabilizer to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas; (iii) optionally adding sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) collecting the resulting amorphous calcium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of CaCl2, and optionally wherein CaCl2 is selected from anhydrous, monohydrate and dihydrate. According to some embodiments, the method includes adding a stabilizer in step (ii). According to some embodiments, the method includes adding a stabilizer in step (iii). According to some embodiments, the method includes adding a stabilizer in both step (ii) and step (iii). According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11 or equal to or higher than 12 throughout the preparation process. According to some embodiments, the pH is maintained at a value from 8 to 12 throughout the preparation process. According to some embodiments, the reaction is carried out at ambient pressure. According to other embodiments, the reaction is carried out at a pressure from 1 bar to 60 bar or from 5 bar to 56 bar. According to some embodiments, the pH is maintained above 10 during the process. According to some embodiments, the method further includes filtering the stabilized ACC. According to some embodiments, the filtering is carried out within 2 minutes from the start of CO2 bubbling. According to some embodiments, the method further includes washing the stabilized ACC. According to some embodiments, the method further includes drying the stabilized ACC.

[0142] According to some embodiments, the method of the present invention comprises the following steps: (i) dissolving a base and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the resulting aqueous solution is 8 or greater; (ii) bubbling or pressurizing CO2 gas into the solution obtained in step (i), and subsequently adding MgSO4 to the solution and optionally adding sodium tripolyphosphate as a stabilizer; (iii) optionally adding sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) collecting the resulting amorphous magnesium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of MgSO4, and optionally wherein the MgSO4 is the heptahydrate. According to some embodiments, the method includes adding a stabilizer in step (ii). According to some embodiments, the method includes adding a stabilizer in step (iii). According to some embodiments, the method includes adding a stabilizer in both step (ii) and step (iii). According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the preparation process. According to some embodiments, the pH is maintained at a value from 8 to 12 throughout the preparation process. According to some embodiments, the reaction is carried out at ambient pressure. According to other embodiments, the reaction is carried out at a pressure from 1 bar to 60 bar or from 5 bar to 56 bar. According to some embodiments, the pH is maintained above 10 during the process. According to some embodiments, the method further includes filtering the stabilized AMC. According to some embodiments, the filtering is carried out within 2 minutes starting from the addition of MgSO4. According to some embodiments, the method further includes washing the stabilized AMC. According to some embodiments, the method further includes drying the stabilized AMC.

[0143] According to some embodiments, the method of the present invention comprises the following steps: (i) dissolving a base and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the resulting aqueous solution is 8 or greater; (ii) adding MgSO4 and optionally sodium tripolyphosphate as a stabilizer to the solution obtained in step (i), subsequently bubbling or pressurizing CO2 gas and optionally adding sodium tripolyphosphate as a stabilizer to the solution; (iii) optionally adding sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) collecting the resulting amorphous magnesium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of MgSO4, and optionally wherein the MgSO4 is the heptahydrate. According to some embodiments, the method includes adding a stabilizer in step (ii). According to some embodiments, the method includes adding a stabilizer in step (iii). According to some embodiments, the method includes adding a stabilizer in both step (ii) and step (iii). According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the preparation process. According to some embodiments, the pH is maintained at a value from 8 to 12 throughout the preparation process. According to some embodiments, the reaction is carried out at ambient pressure. According to other embodiments, the reaction is carried out at a pressure from 1 bar to 60 bar or from 5 bar to 56 bar. According to some embodiments, the pH is maintained above 10 during the process. According to some embodiments, the method further includes filtering the stabilized AMC. According to some embodiments, the filtering is carried out within 2 minutes from the start of CO2 bubbling. According to some embodiments, the method further includes washing the stabilized AMC. According to some embodiments, the method further includes drying the stabilized AMC.

[0144] According to some embodiments, the method is for preparing stabilized calcium carbonate and includes: providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding a base, sodium tripolyphosphate, and calcium chloride to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) continuously collecting the resulting amorphous calcium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount of at least 2 molar equivalents of calcium chloride, and the pH is constantly maintained equal to or higher than 8 throughout the process. According to some embodiments, the pH of the initial solution is equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12. According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the process. According to some embodiments, the pH is maintained at a value from 8 to 12 throughout the preparation process. According to some embodiments, the reaction is carried out at ambient pressure. According to other embodiments, the reaction is carried out at a pressure from 1 bar to 60 bar or from 5 bar to 56 bar. According to some embodiments, the pH is maintained above 10 during the process. According to some embodiments, the method further includes filtering the stabilized ACC. According to some embodiments, the method further includes drying the stabilized ACC. According to some embodiments, the method further includes washing the stabilized ACC.

[0145] According to some embodiments, the method is for preparing stabilized calcium carbonate and includes: providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding an alkali, sodium tripolyphosphate, and magnesium sulfate to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) collecting the resulting amorphous calcium carbonate, wherein the alkali is selected from NaOH and NH4OH and is added in an amount of at least 2 molar equivalents of calcium chloride, and the pH is constantly maintained equal to or higher than 8 throughout the process. According to some embodiments, the pH of the initial solution is equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12. According to some embodiments, the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11, or equal to or higher than 12 throughout the process. According to some embodiments, the pH is maintained at a value from 8 to 12 throughout the preparation process. According to some embodiments, the reaction is carried out at ambient pressure. According to other embodiments, the reaction is carried out at a pressure from 1 bar to 60 bar or from 5 bar to 56 bar. According to some embodiments, the pH is maintained above 10 during the process. According to some embodiments, the method further includes filtering the stabilized AMC. According to some embodiments, the method further includes drying the stabilized AMC. According to some embodiments, the method further includes washing the stabilized AMC.

[0146] According to another aspect, the present invention provides a stabilized amorphous calcium carbonate prepared by the method according to any one of the above embodiments and aspects. All terms, embodiments, and definitions disclosed in any of the above aspects also apply to and are encompassed herein.

[0147] According to some embodiments, the present invention provides a stabilized alkaline earth metal carbonate obtainable or obtained by a method comprising the following steps: (i) dissolving an alkali in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) bubbling or pressurizing CO2 gas into the solution obtained in step (i), followed by adding a salt of an alkaline earth metal; or adding a salt of an alkaline earth metal to the solution obtained in step (i), followed by bubbling or pressurizing CO2 gas into the solution, thereby precipitating an amorphous alkaline earth metal carbonate, and (iii) collecting the resulting precipitate of amorphous alkaline earth metal carbonate, wherein the method includes adding at least one stabilizer in at least one of the following stages: (a) before bubbling or pressurizing CO2 gas; (b) after bubbling or pressurizing CO2 gas; (c) before adding the salt of the alkaline earth metal, (d) together with adding the salt of the alkaline earth metal, or (e) after adding the salt of the alkaline earth metal.

[0148] According to some embodiments, the present invention provides a stabilized alkaline earth metal carbonate obtainable or obtained by a method comprising the following steps: (i) Dissolving an alkali and a stabilizer in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) Bubbling or pressurizing CO2 gas into the solution obtained in step (i), and subsequently adding a salt of an alkaline earth metal and optionally a stabilizer to the solution; or adding a salt of an alkaline earth metal to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas into the solution and optionally adding a stabilizer, (iii) Thereby precipitating a stabilized alkaline earth metal carbonate; (iv) Optionally adding a stabilizer to the solution obtained in step (ii), and (v) Collecting the resulting amorphous alkaline earth metal carbonate, wherein CO2 is continuously introduced into the solution during step (ii) and step (iii) (if present), and the stabilizers in step (i) and step (ii) and / or step (iii) (if present) are the same or different.

[0149] According to some embodiments, the present invention provides a stabilized alkaline earth metal carbonate obtainable or obtained by a method comprising the following steps: (i) Dissolving an alkali in an aqueous solution; (ii) Dissolving a stabilizer in the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas into the solution, wherein dissolving the stabilizer and initiating CO2 introduction by bubbling or pressurizing are carried out in either order; (iii) Adding a salt of an alkaline earth metal and optionally a stabilizer to the solution obtained in step (ii), thereby precipitating an amorphous alkaline earth metal carbonate; and (iv) Optionally adding a stabilizer to the solution obtained in step (iii), wherein CO2 is continuously introduced into the solution during step (ii) and step (iii), and the stabilizers in step (ii) and step (iii) and step (iv) (if added) are the same or different.

[0150] According to some embodiments, the present invention provides a stabilized amorphous calcium carbonate obtainable or obtained by a method comprising the following steps: (i) Dissolving NaOH or NH4OH in an aqueous solution to obtain a pH of 10 or greater; (ii) Dissolve sodium tripolyphosphate in the solution obtained in step (i), and start bubbling or pressurizing CO2 gas into the solution; (iii) Add a halide or sulfate of an alkaline earth metal to the solution of step (ii); (iv) Add sodium tripolyphosphate to the solution of step (iii) or add sodium tripolyphosphate together with step (iii), wherein CO2 is continuously introduced into the solution during steps (ii) and (iii), and wherein NaOH or NH4OH is added in an amount equal to 2 or more molar equivalents of the added alkaline earth metal.

[0151] According to some embodiments, the present invention provides a stabilized amorphous calcium carbonate obtainable or obtained by a method comprising the following steps: (i) Dissolve an alkali in an aqueous solution; (ii) Dissolve a stabilizer in the solution obtained in step (i), and subsequently bubble or pressurize CO2 gas into the solution, wherein dissolving the stabilizer and initiating CO2 introduction by bubbling or pressurizing are carried out in either order; (iii) Add a calcium salt such as calcium chloride and optionally a stabilizer to the solution obtained in step (ii), thereby precipitating ACC; and (iv) Optionally add a stabilizer to the solution obtained in step (iii), wherein CO2 is continuously introduced into the solution during steps (ii) and (iii), and the stabilizers in step (ii) and steps (iii) and (iv) (if added) are the same or different.

[0152] According to some embodiments, the present invention provides a stabilized amorphous calcium carbonate obtainable or obtained by a method comprising the following steps: (i) Dissolve NaOH or NH4OH in an aqueous solution to obtain a pH of 10 or greater; (ii) Dissolve sodium tripolyphosphate in the solution obtained in step (i), and start bubbling or pressurizing CO2 gas into the solution; (iii) Add CaCl2 to the solution of step (ii); (iv) Add sodium tripolyphosphate to the solution of step (iii) or add sodium tripolyphosphate together with step (iii), wherein CO2 is continuously introduced into the solution during steps (ii) and (iii), and wherein NaOH or NH4OH is added in an amount equal to 2 or more molar equivalents of the added CaCl2.

[0153] According to some embodiments, the present invention provides a stabilized amorphous magnesium carbonate, which is obtained or obtainable by a method comprising the following steps: (i) Dissolve an alkali in an aqueous solution; (ii) Dissolve a stabilizer in the solution obtained in step (i), and then bubble or pressurize CO2 gas into the solution, wherein dissolving the stabilizer and initiating CO2 introduction by bubbling or pressurizing are carried out in either order; (iii) Add a magnesium salt such as magnesium sulfate and optionally a stabilizer to the solution obtained in step (ii), thereby precipitating ACC; and (iv) Optionally add a stabilizer to the solution obtained in step (iii), wherein CO2 is continuously introduced into the solution during steps (ii) and (iii), and the stabilizers in step (ii) and steps (iii) and (iv) (if added) are the same or different.

[0154] According to some embodiments, the present invention provides a stabilized amorphous magnesium carbonate, which is obtained or obtainable by a method comprising the following steps: (i) Dissolve NaOH or NH4OH in an aqueous solution to obtain a pH of 10 or greater; (ii) Dissolve sodium tripolyphosphate in the solution obtained in step (i), and start bubbling or pressurizing CO2 gas into the solution; (iii) Add MgCl2 or magnesium sulfate to the solution of step (ii); (iv) Add sodium tripolyphosphate to the solution of step (iii) or add sodium tripolyphosphate together with step (iii), wherein CO2 is continuously introduced into the solution during steps (ii) and (iii), and wherein NaOH or NH4OH is added in an amount equal to 2 or more molar equivalents of the added magnesium salt.

[0155] According to some embodiments, the present invention provides a stabilized amorphous magnesium carbonate, which is obtained or obtainable by a method comprising the following steps: (i) Dissolve NaOH or NH4OH and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the resulting aqueous solution has a pH of 8 or greater; (ii) Bubble or pressurize CO2 gas into the solution obtained in step (i), then add CaCl2 and / or NH4OH to the solution and optionally add sodium tripolyphosphate as a stabilizer; (iii) Optionally add sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) Collect the obtained amorphous carbonate of Ca and / or Mg.

[0156] According to some embodiments, the present invention provides a stabilized amorphous magnesium carbonate, which is obtained or obtainable by a method comprising the following steps: (i) Dissolve NaOH or NH4OH and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the obtained aqueous solution is 8 or higher; (ii) Add CaCl2 or MgSO4 and optionally sodium tripolyphosphate as a stabilizer to the solution obtained in step (i), and then bubble or pressurize CO2 gas; (iii) Optionally add sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) Collect the obtained amorphous carbonate of Ca and / or Mg.

[0157] According to some embodiments, the present invention provides a stabilized alkaline earth metal carbonate, which is obtained or obtainable by a method comprising the following steps: providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding an alkali, at least one stabilizer, and an alkaline earth metal or its salt to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) continuously collecting the obtained stabilized amorphous alkaline earth metal carbonate, wherein the pH is maintained equal to or higher than 8 throughout the process. According to some embodiments, the alkaline earth metal or its salt is selected from CaCl2 and MgSO4.

[0158] According to yet another aspect, the present invention provides the use of stabilized amorphous alkaline earth metal carbonates such as ACC, AMC, and combinations thereof in agriculture and veterinary medicine.

[0159] The present invention has been generally described above. The present invention will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended to limit the present invention.

[0160] Examples The properties of the products prepared in the examples described herein are provided in Table 1 below. Several examples were repeated under slightly different conditions. A detailed description of these variations is presented in Table 1.

[0161] Example 1. Preparation of ACC using 10% stabilizer introduced in one addition step and two equivalents of NaOH with CO2 bubbling at atmospheric pressure.

[0162] Dissolve sodium hydroxide pellets (7 g, two molar equivalents of CaCl₂) in 250 ml of deionized water. Then dissolve the stabilizer (sodium tripolyphosphate, STPP, also known as sodium triphosphate) (1.26 g, 10 wt% of the amount of CaCl₂ . 2H₂O) in the solution. Before adding the calcium reagent, bubble CO₂ gas through the solution for at least 2 minutes and continue bubbling throughout the reaction after adding the calcium source. Add 12.61 g of CaCl₂ . 2H₂O in small portions (due to the exothermic reaction) until CaCl₂ . 2H₂O is dissolved in the above solution mixture under a constant gentle CO₂ stream. The reaction mixture is homogenized by a homogenizer, and after filtration, washing with water, and drying, CO₂ is further bubbled into the reaction mixture for a total time of 10 minutes to produce 3.2 g of a white solid. In this particular example, the solid is dried by air purging in an oven at 100 °C for 15 minutes. The calculated yield based on the molar amounts of the assumed ACC composition and the calcium source is approximately 30%.

[0163] Example 2. Preparation of ACC using 5% stabilizer introduced in one step and two equivalents of NaOH with CO₂ bubbling at atmospheric pressure.

[0164] Dissolve sodium hydroxide pellets (7 g, two molar equivalents of CaCl₂) in 200 ml of deionized water. Then dissolve the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, 5 wt% of the amount of CaCl₂ . 2H₂O) in the solution. Before adding the calcium source, bubble CO₂ gas through the solution to degas the solution from other gases and continue bubbling throughout the reaction after adding the calcium source. Add 12.61 g of CaCl₂ . 2H₂O dissolved in 50 ml of deionized water to the above solution mixture under a constant gentle CO₂ stream. The reaction mixture is homogenized by a homogenizer, and CO₂ is further bubbled into the reaction mixture for a total time of 10 minutes to produce 7.8 g of a white solid (yield is 73% based on the molar amounts of the assumed ACC composition and the calcium source). The calcium content is 39.7 wt%. The surface area of the resulting ACC is 18.49 m 2 / g.

[0165] Example 3. Preparation of ACC using 10% stabilizer added in two portions and two equivalents of NaOH with CO₂ bubbling at atmospheric pressure.

[0166] A certain amount of NaOH pellets (7 g, two equivalents) was dissolved in 250 ml of deionized water. Then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, 5 wt% of the amount of CaCl2 . 2H2O) was dissolved. Then, before adding the calcium source, CO2 gas was bubbled through the solution for different periods of time and was continuously bubbled throughout the reaction with the calcium source. A 12.61 g amount of CaCl2 . 2H2O was added in small portions (the reaction is exothermic) until CaCl2 . 2H2O was dissolved in the above solution mixture under a constant gentle CO2 stream. The reaction mixture was homogenized by a homogenizer and CO2 was further bubbled into the reaction mixture. Another 0.63 g of STPP was added and the reaction was continued for an additional 5 min. The total yield was 5.5 g of a white solid (51% yield) and the calcium content was 34.4 wt%. The surface area of the resulting ACC was 11 m 2 / g.

[0167] The reaction can be carried out at higher pressures (from 5 bar to 200 bar). It can be carried out with additional ion sources of other metals (e.g., Mg, Fe, Mn, Cr, Co, etc.) It seems that increasing the amount of base can increase the yield of the reaction.

[0168] Example 4. Preparation of ACC by bubbling CO2 at atmospheric pressure without using sodium hydroxide and using a 10% stabilizer added in one portion.

[0169] At atmospheric pressure, 1.26 g (10 wt% of the amount of CaCl2 . 2H2O) of the stabilizer (sodium tripolyphosphate, STPP) was dissolved in a conical flask containing 250 ml of deionized water. A 12.61 g amount of CaCl2 . 2H2O was added in small portions (the reaction is exothermic) until CaCl2 . 2H2O was dissolved in the above solution mixture under a constant gentle CO2 stream. The reaction mixture was homogenized with a homogenizer and CO2 was further bubbled into the reaction mixture for a total time of 10 min. The yield of the recovered product was only 1.2 g and TGA indicated that only 2 wt% CO2 was released, indicating a very low carbonate product content. The product was found to be amorphous.

[0170] Example 5. Preparation of ACC by bubbling CO2 at atmospheric pressure without using sodium hydroxide and using a 10% stabilizer added in two steps.

[0171] At atmospheric pressure, 0.63 g (5 wt% of the amount of CaCl2 . 2H2O) of a stabilizer (sodium tripolyphosphate, STPP) was dissolved in a conical flask containing 250 ml of deionized water. 12.61 g of the amount of CaCl2 . 2H2O was added in small portions until CaCl2 . 2H2O was dissolved in the above solution mixture under a constant and gentle CO2 stream. Another 0.63 g of the stabilizer as a powder was added. The reaction mixture was homogenized by a homogenizer, and CO2 was further bubbled into the reaction mixture for a total time of 10 min. The yield of the recovered product was only 1 g, and TGA indicated that only 2 wt% CO2 was released, indicating a very low calcium carbonate content. This material was amorphous.

[0172] Example 6. Preparation of ACC using 10% stabilizer added in two steps without using sodium hydroxide under CO2 bubbling at atmospheric pressure.

[0173] At atmospheric pressure, 0.63 g (5 wt% of the amount of CaCl2 . 2H2O) of a stabilizer (sodium tripolyphosphate, STPP) was dissolved in a conical flask containing 250 ml of deionized water. 12.61 g of the amount of CaCl2 . 2H2O was added in small portions until CaCl2 . 2H2O was dissolved in the above solution mixture under a constant and gentle CO2 stream. Another 0.63 g of STPP was added, and the reaction mixture was homogenized by a homogenizer, and CO2 was further bubbled into the reaction mixture for a total time of 10 min. The yield of the recovered product was only 1.2 g, and TGA indicated that only 2 wt% CO2 was released, indicating a very low calcium carbonate content. The material was amorphous and contained 23.9% calcium. The surface area of the obtained ACC was 32.9 m 2 / g.

[0174] Example 7. Preparation of ACC using 10% stabilizer added in a single addition and three equivalents of sodium hydroxide under CO2 bubbling at atmospheric pressure Sodium hydroxide pellets (10.5 g; 3 equivalents compared to CaCl2 . 2H2O) were dissolved in 200 ml of deionized water, and then the stabilizer (sodium tripolyphosphate, STPP) (1.26 g, CaCl2 .An amount of 10 wt% of CaCl₂·2H₂O was dissolved in the solution. Then, before adding the calcium source, CO₂ was bubbled through the solution and continuously bubbled throughout the reaction with the calcium source. 12.61 g of CaCl₂ dissolved in 50 ml of water . ·2H₂O was added in the presence of a constant and gentle CO₂ stream. The reaction mixture was homogenized by a homogenizer, and CO₂ was further bubbled into the reaction mixture for a total time of 10 minutes to produce 9.5 g of a white solid (yield of ACC: 88%). The calcium content was 34.3 wt%. The surface area of the resulting ACC was 44.45 m 2 / g.

[0175] Example 8. Preparation of ACC using calcium chloride, sodium tripolyphosphate (STPP) as a stabilizer (single addition), and three equivalents of sodium hydroxide under CO₂ bubbling at atmospheric pressure Sodium hydroxide pellets (10.5 g; three equivalents compared to CaCl₂ . ·2H₂O) were dissolved in 150 ml of deionized water, and then the stabilizer (sodium tripolyphosphate, STPP) (1.26 g, 10 wt% of the amount of CaCl₂ . ·2H₂O) was dissolved in the solution. Then, before adding the calcium source, CO₂ gas was bubbled through the solution and continuously bubbled throughout the reaction with the calcium source. 12.61 g of CaCl₂ dissolved in 50 ml of water . ·2H₂O was added in the presence of a constant and gentle CO₂ stream. The reaction mixture was homogenized by a homogenizer, and CO₂ was further bubbled into the reaction mixture for a total time of 10 minutes to produce 7.6 g of a white solid (yield of ACC: 71%). The surface area of the resulting ACC was 28.6 m 2 / g.

[0176] Example 9. Preparation of ACC using 10% stabilizer added in two portions and three equivalents of sodium hydroxide under CO₂ bubbling at atmospheric pressure Sodium hydroxide pellets (10.5 g; three equivalents compared to CaCl₂ . ·2H₂O) were dissolved in 200 ml of deionized water, and then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, 5 wt% of the amount of CaCl₂ . ·2H₂O) was dissolved in the solution. Then, before adding the calcium source, CO₂ was bubbled through the solution and continuously bubbled throughout the reaction with the calcium source. 12.61 g of CaCl₂ dissolved in 50 ml of water .2H2O and another 0.63 g of STPP were added in the presence of a constant gentle stream of CO2. The reaction mixture was homogenized by a homogenizer, and CO2 was further bubbled into the reaction mixture, and the reaction was continued for an additional 5 minutes. The total yield was 9.5 g of a white solid (88% yield of ACC).

[0177] Example 10. Preparation of ACC using 10% stabilizer added in a single step and three equivalents of sodium hydroxide in the presence of 10 bar of CO2 in a 1 L pressure reactor Sodium hydroxide pellets (10.5 g; 3 equivalents compared to CaCl2 . 2H2O) were dissolved in 200 ml of deionized water, and then the stabilizer (sodium tripolyphosphate, STPP) (1.26 g, 10 wt% of the amount of CaCl2 . 2H2O) was dissolved in the solution. The 12.61 g amount of CaCl2 . 2H2O dissolved in 50 ml of water was immediately added to the above mixture, the resulting solution was blended and then introduced into the pressure reactor. Then CO2 gas was flushed through the solution in the reactor to degas the solution. The reactor was sealed and pressurized at 10 bar of CO2 for 10 minutes. The reaction mixture was stirred by a mechanical rotor stirring shaft set at 1000 rpm. After filtration, washing with water and drying by air purging in an oven at 100 °C for 15 minutes, the reaction yield was 6.9 g of a white solid (64% yield of ACC).

[0178] Example 11. Preparation of ACC using 10% stabilizer added in two steps and three equivalents of sodium hydroxide in the presence of 10 bar of CO2 in a 1 L pressure reactor Sodium hydroxide pellets (10.5 g; 3 equivalents compared to CaCl2 . 2H2O) were dissolved in 200 ml of deionized water, and then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, 5 wt% of the amount of CaCl2 . 2H2O) was dissolved in the solution. The 12.61 g amount of CaCl2 . 2H2O was dissolved in 40 ml of water, and then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, CaCl2 .The amounts of 2H2O (5 wt%) were separately dissolved in 10 ml of water. The calcium solution and the STPP solution were premixed to a total volume of 50 ml and immediately added to the above 200 ml mixture. The resulting solution was blended, added to the reactor, and CO2 was flushed through the solution in the reactor. Then the reactor was sealed and the pressure was set to 10 bar for 10 minutes. The reaction mixture was stirred with a mechanical rotor stirrer shaft set at 1000 rpm. After filtration, washing, and drying by air purging in an oven at 100 °C for 15 minutes, the product yield was 7.1 g of a white solid (the yield of ACC was 66%).

[0179] Example 12. Preparation of ACC using 10% stabilizer added in a single step and two equivalents of sodium hydroxide in the presence of 10 bar CO2 in a 1 L pressure reactor The sodium hydroxide pellets (7 g; 2 equivalents compared to CaCl2 . 2H2O) were dissolved in 200 ml of deionized water, and then the stabilizer (sodium tripolyphosphate, STPP) (1.26 g, 10 wt% of the amount of CaCl2 . 2H2O) was dissolved in the solution. The 12.61 g amount of CaCl2 . 2H2O dissolved in 50 ml of water was immediately added to the above mixture. The resulting solution was blended and added to the reactor. CO2 was flushed through the solution in the reactor. Then the reactor was sealed and the CO2 pressure was set to 10 bar for a total time of 10 minutes. The reaction mixture was blended with a mechanical rotor stirrer shaft set at 1000 rpm to produce 6.7 g of a white solid (the yield of ACC was 62%).

[0180] Example 13. Preparation of ACC using 10% stabilizer added in two steps and two equivalents of sodium hydroxide in the presence of 10 bar CO2 in a 1 L pressure reactor The sodium hydroxide pellets (7 g; 2 equivalents compared to CaCl2 . 2H2O) were dissolved in 200 ml of deionized water, and then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, 5 wt.% of the amount of CaCl2 . 2H2O) was dissolved in the solution. The 12.61 g amount of CaCl2 . 2H2O was dissolved in 40 ml of water, and then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, 5 wt.% of the amount of CaCl2 .The amount of 2H2O (5 wt.%) was separately dissolved in 10 ml of water. The calcium solution and the STPP solution were premixed to a total volume of 50 ml and immediately added to the above 200 ml mixture. The resulting solution was blended and added to the reactor, and CO2 was flushed through the solution in the reactor. Then the reactor was sealed, and the CO2 pressure was set to 10 bar for a total time of 10 minutes. The reaction mixture was stirred by a mechanical rotor stirring shaft set at 1000 rpm to produce 6.7 g of a white solid (the yield of ACC was 62%).

[0181] Example 14. Preparation of ACC using 10% stabilizer added in two steps and two equivalents of sodium hydroxide in the presence of 20 bar CO2 in a 1 L pressure reactor Sodium hydroxide pellets (7 g; 2 equivalents compared to CaCl2 . 2H2O) were dissolved in 250 ml of deionized water, then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, CaCl2 . 5 wt.% of the amount of 2H2O) was dissolved in the solution, and CO2 was pressurized to 20 bar in a sealed reactor at room temperature for 10 min. The reactor was opened, the solution was transferred to a conical flask, and the mixture was blended with a homogenizer. An amount of 12.61 g of powdered CaCl2 . 2H2O was added to the above mixture, followed by the addition of 0.63 g of powdered stabilizer (sodium tripolyphosphate, STPP, 5 wt.% of the amount of CaCl2 . 2H2O). The resulting solution was homogenized for an additional 3 min to produce 7.7 g of a white solid (the yield of ACC was 72%).

[0182] Example 15. Preparation of ACC using 10% stabilizer added in two steps and three equivalents of sodium hydroxide in the presence of 20 bar CO2 in a 1 L pressure reactor Sodium hydroxide pellets (10.5 g; 3 equivalents compared to CaCl2 . 2H2O) were dissolved in 250 ml of deionized water, then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, CaCl2 . 5 wt.% of the amount of 2H2O) was dissolved in the solution, and CO2 was pressurized to 20 bar in a sealed reactor at room temperature for 10 min. The reactor was opened, the solution was transferred to a conical flask, and the mixture was blended with a homogenizer. An amount of 12.61 g of powdered CaCl2 . 2H2O was added to the above mixture, followed by the addition of 0.63 g of powdered stabilizer (sodium tripolyphosphate, STPP, CaCl2. 5 wt.% of the amount of 2H2O). The resulting solution was homogenized for an additional 3 min to produce 10.4 g of a white solid (yield of ACC was 97%).

[0183] Example 16. Preparation of ACC using 10% stabilizer added in two portions and two equivalents of sodium hydroxide in the presence of 20 bar CO2 in a 1 L pressure reactor Sodium hydroxide pellets (7 g; 2 equivalents compared to CaCl2 . 2H2O) were dissolved in 200 ml of deionized water, then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, 5 wt.% of the amount of CaCl2 . 2H2O) was dissolved in the solution, and CO2 was pressurized to 20 bar at room temperature into the sealed reactor for 10 min. The reactor was opened, the solution was transferred to a conical flask, and the mixture was blended by a homogenizer. 12.61 g of powdered CaCl2 . 2H2O dissolved in 40 ml of deionized water was added to the above mixture, followed by 0.63 g of powdered stabilizer (sodium tripolyphosphate, STPP, 5 wt.% of the amount of CaCl2 . 2H2O) dissolved in 10 ml of deionized water. The resulting solution was homogenized for an additional 3 min to produce 7.6 g of a white solid (yield of ACC was 71%).

[0184] Example 17. Preparation of ACC using 10% stabilizer added in two steps and three equivalents of sodium hydroxide in the presence of 20 bar CO2 in a 1 L pressure reactor Sodium hydroxide pellets (10.5 g; 3 equivalents compared to CaCl2 . 2H2O) were dissolved in 200 ml of deionized water, then the stabilizer (sodium tripolyphosphate, STPP) (0.63 g, 5 wt.% of the amount of CaCl2 . 2H2O) was dissolved in the solution, and CO2 was pressurized to 20 bar at room temperature into the sealed reactor for 10 min. The reactor was opened, the solution was transferred to a conical flask, and the mixture was blended by a homogenizer. 12.61 g of powdered CaCl2 . 2H2O dissolved in 40 ml of deionized water was added to the above mixture, followed by 0.63 g of powdered stabilizer (sodium tripolyphosphate, STPP, 5 wt.% of the amount of CaCl2 . 2H2O) dissolved in 10 ml of deionized water. The resulting solution was homogenized for an additional 3 min to produce 9.8 g of a white solid (yield of ACC was 91%).

[0185] Example 18. Preparation of ACC using 10% stabilizer added in a single step but without sodium hydroxide in the presence of 10 bar CO2 in a 1 L pressure reactor To 200 ml of deionized water, the stabilizer (sodium tripolyphosphate, STPP) (1.26 g, 10 wt% of the amount of CaCl2 . 2H2O) was dissolved in the solution. The amount of 12.61 g of CaCl2 . 2H2O dissolved in 50 ml of water was immediately added to the above mixture, the resulting solution was blended and added to the reactor. CO2 was flushed through the solution in the reactor. Then the reactor was sealed and the pressure was set to 10 bar for a total time of 10 minutes. The reaction mixture was stirred with a mechanical rotor stirring shaft set at 1000 rpm to produce 1.1 g of a white solid (yield of ACC was 10%).

[0186] Example 19. Preparation of ACC using 10% stabilizer added in a single step but without sodium hydroxide in the presence of 20 bar CO2 in a 1 L pressure reactor To 200 ml of deionized water, the stabilizer (sodium tripolyphosphate, STPP) (1.26 g, 10 wt% of the amount of CaCl2 . 2H2O) was dissolved in the solution. The amount of 12.61 g of CaCl2 . 2H2O dissolved in 50 ml of water was immediately added to the above mixture, the resulting solution was blended and added to the reactor. CO2 gas was flushed through the solution in the reactor. Then the reactor was sealed and the pressure was set to 20 bar for a total time of 10 minutes. The reaction mixture was stirred with a mechanical rotor stirring shaft set at 1000 rpm to produce 1.1 g of a white solid (yield of ACC was 10%).

[0187] Example 20. The same preparation as in Example 7 and Example 12, but without adding a stabilizer When preparing ACC without adding a stabilizer as detailed in Example 7 and Example 12, the resulting ACC crystallized immediately in the solution.

[0188] Example 21. Preparation of ACC (2730) using 10% stabilizer added in a single step and 2 equivalents of NH4OH solution in the presence of 10 bar CO2 in a 1 L pressure reactor The ammonium hydroxide solution (25 wt% NH3) (11.7 ml; with CaCl2 .2 equivalents relative to 2H2O) was dissolved in 200 ml of deionized water, and then the stabilizer (sodium tripolyphosphate, STPP) (1.26 g, 10 wt.% of the amount of CaCl2 . 2H2O) was dissolved in the solution. Before adding the calcium source, CO2 was bubbled through the solution. 12.61 g of CaCl2 . 2H2O dissolved in 50 ml of deionized water was added to the above solution mixture under a constant gentle stream of CO2. The reactor was sealed and the reaction was continued at 25 °C at 10 bar for one minute while stirring with a mechanical rotor shaft set at 1000 RPM. After 1 minute, the reaction was terminated, then the reactor was opened and the product was filtered on a Büchner funnel with filter paper. The product was dried in a 100 °C oven with a vent to produce 8.8 g of a white solid (yield of ACC was 82%). As measured by XRD, the amorphous content of ACC was 100%. The loss on drying of ACC was 10.4%, and the calcium content was 32.9 wt%.

[0189] Example 22. Preparation of AMC (2754) using 6.4% stabilizer added in one addition and two equivalents of ammonium hydroxide in the presence of 15 bar CO2 in a 1 L pressure reactor To 200 ml of deionized water, the stabilizer (sodium tripolyphosphate, STPP) (0.898 g, 6.4 wt.% of the amount of MgSO4) was dissolved in the solution together with 25 wt.% ammonia liquor solution (2 equivalents relative to MgSO4, 15.8 ml). 28.57 g of MgSO4 . 7H2O dissolved in 50 ml of water was immediately added to the above mixture, and the resulting solution was blended for 30 seconds and added to the reactor. CO2 gas was flushed through the solution in the reactor. Then the reactor was sealed and the pressure was set to 15 bar for a total time of 3 minutes. The reaction mixture was stirred with a mechanical rotor shaft set at 1000 rpm to produce 1 g of a white solid after precipitation with 30 ml of ethanol. The product was washed with 500 ml of deionized water to remove unreacted starting materials and salts and dried in an oven without a vent to a constant 4.7% L.O.D., XRD 100% AMC (yield of AMC was 6%).

[0190] Example 23. Preparation of AMC (2755) using 6.4% stabilizer added in one addition and two equivalents of ammonium hydroxide in the presence of 15 bar CO2 in a 1 L pressure reactor In 200 ml of deionized water, a stabilizer (sodium tripolyphosphate, STPP) (0.898 g, 6.4 wt% of the amount of MgSO4) was dissolved in the solution together with 25 wt.% ammonia solution (2 equivalents compared to MgSO4, 15.8 ml). A 28.57 g amount of MgSO4 . 7H2O was immediately added to the above mixture, and the resulting solution was blended for 30 seconds and added to the reactor. CO2 gas was flushed through the solution in the reactor. Then the reactor was sealed, and the pressure was set to 15 bar for a total time of 5 minutes. The reaction mixture was stirred by a mechanical rotor shaft set at 1000 rpm to produce 1.5 g of a white solid after precipitation with 50 ml of ethanol. The product was washed with 500 ml of deionized water to remove unreacted starting materials and salts and dried in an oven without a vent to a constant 5.1% L.O.D., XRD 100% AMC (yield of AMC was 9.4%).

[0191] Example 24. Preparation of AMC (2761) without adding a stabilizer but using two equivalents of ammonia solution in the presence of 15 bar CO2 in a 1 L pressure reactor To 200 ml of deionized water, 25 wt.% ammonia solution (2 equivalents, 15.8 ml) was added. A 28.57 g amount of MgSO4 . 7H2O was immediately added to the above solution, and the resulting mixture was blended for 30 seconds and added to the reactor. CO2 was flushed through the solution in the reactor. Then the reactor was sealed, and the pressure was set to 15 bar for a total time of 3 minutes. The reaction mixture was stirred by a mechanical rotor stirring shaft set at 1000 rpm to produce 1.1 g of a white solid after precipitation with 50 ml of ethanol. The product was washed with 500 ml of deionized water to remove unreacted starting materials and salts and dried in an oven without a vent to a constant 3.6% L.O.D., XRD mainly AMC and a small amount of hydromagnesite (yield of AMC was 6%).

[0192] Example 25. Preparation of AMC (2766) using 6.4% stabilizer added in one portion and two equivalents of ammonium in the presence of 15 bar CO2 in a 1 L pressure reactor To 200 ml of deionized water, 25 wt.% ammonia solution (2 equivalents, 15.8 ml) was added together with a stabilizer (sodium tripolyphosphate, STPP, 0.898 g, 6.4 wt% of the amount of MgSO4). A 28.57 g amount of MgSO4 .7H2O was immediately added to the above solution, and the resulting mixture was blended for 30 seconds and added to the reactor. CO2 was flushed through the solution in the reactor. Then the reactor was sealed, and the pressure was set to 15 bar for a total time of 3 minutes. The reaction mixture was stirred by a mechanical rotor shaft set at 1000 rpm to produce 6.3 g of a white solid after precipitation with 50 ml of ethanol. The product was separated as-is without washing with deionized water and dried in an oven without a vent to a constant 5.4% L.O.D., XRD 100% AMC (yield of AMC was 55%).

[0193] Example 26. Preparation of ACC using 10% stabilizer added in a single step and 2 equivalents of NH4OH solution in the presence of 10 bar CO2 in a 1 L pressure reactor Ammonium hydroxide solution (25 wt% NH3) (11.7 ml; 2 equivalents compared to CaCl2 . 2H2O) was dissolved in 200 ml of deionized water, and then the stabilizer (pyrophosphoric acid / pyrophosphate / pyrophosphite, hexametaphosphoric acid / hexametaphosphate / hexametaphosphite, phytic acid or citric acid) (10 wt.% of the amount of CaCl2 . 2H2O) was dissolved in the solution. Before adding the calcium source, CO2 was bubbled through the solution. An amount of 12.61 g of CaCl2 . 2H2O dissolved in 50 ml of deionized water was added to the above solution mixture under a constant gentle stream of CO2. The reactor was sealed and the reaction was continued at 25 °C at 10 bar for one minute while stirring with a mechanical rotor shaft set at 1000 RPM. The reaction was terminated after 1 minute, then the reactor was opened and the product was filtered on a Buchner funnel with filter paper. The product was dried in an oven at 100 °C with a vent to produce 8 g - 10 g of a white solid. The amorphous content of ACC was 100% as measured by XRD.

[0194] Example 27. Preparation of AMC using 6.4% stabilizer added in one addition and two equivalents of ammonium in the presence of 15 bar CO2 in a 1 L pressure reactor In 200 ml of deionized water, 25 wt.% ammonia solution (2 equivalents, 15.8 ml) and stabilizer (pyrophosphoric acid / pyrophosphate / pyrophosphite, hexametaphosphoric acid / hexametaphosphate / hexametaphosphite, phytic acid or citric acid, 6.4 wt% of the amount of MgSO4) were added. An amount of 28.57 g of MgSO4 .7H2O was immediately added to the above solution, and the resulting mixture was blended for 30 seconds and added to the reactor. CO2 was flushed through the solution in the reactor. Then the reactor was sealed, and the pressure was set to 15 bar for a total time of 3 minutes. The reaction mixture was stirred by a mechanical rotor shaft set at 1000 rpm to produce 6.3 g of a white solid after precipitation with 50 ml of ethanol. The product was separated as-is without washing with deionized water and dried in an oven without a vent to a constant ~5.5% L.O.D., XRD 100% AMC (yield of AMC was ~55%).

[0195] Example 28. Preparation of ACC using 10% stabilizer added in a single step and 2 equivalents of NH4OH solution in the presence of 10 bar CO2 in a 1 L pressure reactor Ammonium hydroxide solution (25 wt% NH3) (11.7 ml; 2 equivalents compared to CaCl2 . 2H2O) was dissolved in 200 ml of deionized water, and then the stabilizer (a combination of tripolyphosphoric acid / tripolyphosphate / tripolyphosphite with one of the following: pyrophosphoric acid / pyrophosphate / pyrophosphite, hexametaphosphoric acid / hexametaphosphate / hexametaphosphite, phytic acid, or citric acid) (10 wt.% of the amount of CaCl2 . 2H2O) was dissolved in the solution. Before adding the calcium source, CO2 was bubbled through the solution. An amount of 12.61 g of CaCl2 . 2H2O dissolved in 50 ml of deionized water was added to the above solution mixture in the presence of a constant gentle CO2 stream. The reactor was sealed and the reaction was continued at 25 °C at 10 bar for one minute while stirring with a mechanical rotor shaft set at 1000 RPM. After one minute, the reaction was terminated, then the reactor was opened, and the product was filtered through filter paper on a Buchner funnel. The product was dried in a 100 °C oven with a vent to produce 8 g - 10 g of a white solid. As measured by XRD, the amorphous content of ACC was 100%.

[0196] Example 29. Preparation of AMC using 6.4% stabilizer added in one addition and two equivalents of ammonium in the presence of 15 bar CO2 in a 1 L pressure reactor In 200 ml of deionized water, 25 wt.% ammonia solution (2 equivalents, 15.8 ml) and a stabilizer (a combination of tripolyphosphoric acid / tripolyphosphate / tripolyphosphite with one of the following: pyrophosphoric acid / pyrophosphate / pyrophosphite, hexametaphosphoric acid / hexametaphosphate / hexametaphosphite, phytic acid, or citric acid, 6.4 wt% of the amount of MgSO4) were added. An amount of 28.57 g of MgSO4 .7H2O was immediately added to the above solution and the resulting mixture was blended for 30 seconds and added to the reactor. CO2 was flushed through the solution in the reactor. The reactor was then sealed and the pressure was set at 15 bar for a total time of 3 minutes. The reaction mixture was stirred by a mechanical rotor stirrer shaft set at 1000 rpm to yield 6.3 g of a white solid after precipitation with 50 ml of ethanol. The product was separated as such without washing with deionized water and dried in an oven without a vent to a constant ~5.5% L.O.D., XRD 100% AMC (yield of AMC was ~55%).

[0197] The analytical results of the above-described examples are summarized in Table 1 and point out several important issues. First, the presence of a base is crucial for the conversion of CO2 into carbonate and bicarbonate ions. In fact, the stoichiometry of the reaction with salts of alkaline earth metals requires at least 2 equivalents of base (OH - ) to complete the chemical reaction. We have indications that higher levels of base equivalents may be beneficial to ensure a high yield of the amorphous product.

[0198] Without being bound by any particular theory, it is assumed that the base can react directly with CO2 before the introduction of the salts of alkaline earth metals. However, the base can also initially react with the metal salt to form M-OH species (M = Ca or Mg), which are bases themselves and then can react with CO2. This means that if the industrial waste is an alkaline earth metal hydroxide, CO2 will be able to form the desired amorphous carbonate without the addition of a base. However, to our knowledge, current industrial wastes containing calcium and magnesium mainly consist of alkaline earth metal chlorides and alkaline earth metal sulfates, which are derived from the dissolution of metal-containing rocks in sulfuric or hydrochloric acid. While magnesium sulfate (epsom salt) is very soluble and can thus be used in a given example, calcium sulfate (gypsum) is a very insoluble material.

[0199] The presence of a base is also important for stabilizing the initially formed amorphous carbonate in the reaction solution before separating and drying the initially formed amorphous carbonate in the reaction solution. Our experience is that during large-scale industrial processes of these amorphous carbonates, the amorphous product in the suspension or wet process stage is very susceptible to crystallization by the solid-solution-solid crystallization mechanism. The presence of stabilizers and also the alkaline pH level are crucial for inhibiting crystallization in these process stages or if the amorphous product is intentionally used as a suspension for practical applications. In a basic solution, the solubility of the amorphous carbonate is significantly reduced. In contrast, they are significantly more soluble in acidic and even neutral conditions compared to the related crystalline phases of the amorphous carbonate. Therefore, in a given example, the pH of the reaction solution was maintained above pH 8.

[0200] The most commonly used bases are sodium hydroxide and dissolved ammonia (NH4OH). In addition, these bases are also inexpensive and are produced in very large quantities. The process based on one or the other base will be determined according to economic evaluation, availability, location, and environmental factors related to the industrial plant used to manufacture the products of the present invention.

[0201] As shown in Example 20, the presence of a stabilizer is very critical in the formation of ACC. The amount of the stabilizer and the order of its introduction are less important. In most examples, 10% stabilizer is used. However, as seen from Example 2, 5% stabilizer is also suitable. As shown in Example 24, the presence of a stabilizer in the formation of AMC is less important for the ability to produce an AMC that is stable under dry conditions. However, for the long-term stability of AMC in a humid environment or if suspended in an aqueous solution in certain applications, a stabilizer is required because the stability of AMC deteriorates rapidly in the absence of a stabilizer and the AMC crystallizes quickly. Regardless of the variations in the synthesis, in all examples that give high yields, the ACC produced is very similar in its molecular arrangement. However, the chemical content and molecular arrangement of AMC can vary widely based on the variables and order during its synthesis.

[0202] In addition, recent detailed studies using advanced solid-state NMR techniques have revealed that both the amorphous and crystalline phases of magnesium carbonate also have magnesium bicarbonate species and their salts (e.g., Leukel et al., Hydrogen Bonding in Amorphous Alkaline Earth Carbonates, Inorg. Chem. 2018, 57, 11289−11298; Moore et al., Quantitative Identification of Metastable Magnesium Carbonate Minerals by Solid-State 1313C NMR Spectroscopy. Environ. Sci. Technol. 2015, 49, 657−664; and Tanaka et al., Transformation process of amorphous magnesium carbonate in aqueous solution. Journal of Mineralogical and Petrological Sciences, Vol. 114, pp. 105–109, 2019). Considering the disordered structure of AMC, this is not very surprising, and it is even more surprising that they exist in a crystalline phase.

[0203] Many stabilizers other than the exemplary stabilizers can be used. Tripolyphosphoric acid / tripolyphosphate / triphosphate is a very reliable stabilizer with a very low cost and is used in very large amounts in food processing (preservation). However, any of the following stabilizers can be used: polyphosphoric acid / polyphosphate / polyphosphate, organic acids, phosphorylated amino acids, phosphorylated, phosphonated, sulfated, or sulfonated organic compounds, phosphate or sulfate esters of hydroxycarboxylic acids, diphosphonic acid / diphosphonate / diphosphonate, organic polyphosphoric acid / polyphosphate / polyphosphate, polyphosphoric acid / polyphosphate / polyphosphate, organic compounds having a hydroxy group, their derivatives, proteins, and any combination thereof. More specific examples of useful stabilizers are serine phosphate, citric acid, sodium citrate and citric acid, adenosine triphosphate, adenosine diphosphate, phytic acid, etidronic acid, pyrophosphoric acid / pyrophosphate / pyrophosphate, polyphosphoric acid / polyphosphate / polyphosphate, hexametaphosphoric acid / hexametaphosphate / hexametaphosphate, ethanol, its salts, and any combination thereof.

[0204] In addition, stabilizers can be found or produced around the following location where waste calcium salts and magnesium salts can be found during the production of phosphates from natural calcium phosphate minerals.

[0205] Although no examples of mixed amorphous calcium carbonate - magnesium carbonate are given, their formation as stable amorphous compositions is highly feasible, as demonstrated recently in WO2022162667 - Particles Comprising Amorphous Divalent Metal Carbonate.

[0206] Although the present invention has been described above by way of preferred embodiments of the present invention, the present invention can be modified without departing from the spirit and nature of the present invention as defined in the appended claims.

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Claims

1. A method for preparing a stabilized amorphous alkaline earth metal carbonate, the method comprising: (i) dissolving an alkali in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) bubbling or pressurizing CO2 gas into the solution obtained in step (i), and subsequently adding a salt of an alkaline earth metal; or adding a salt of an alkaline earth metal to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas into the solution, thereby precipitating an amorphous alkaline earth metal carbonate, and (iii) collecting the resulting precipitate of amorphous alkaline earth metal carbonate, wherein the method comprises adding at least one stabilizer in at least one of the following stages: (a) before bubbling or pressurizing CO2 gas; (b) after bubbling or pressurizing CO2 gas; (c) before adding the salt of the alkaline earth metal, (d) together with the addition of the salt of the alkaline earth metal, or (e) after adding the salt of the alkaline earth metal.

2. The method according to claim 1, wherein the method comprises: (i) dissolving an alkali in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) bubbling or pressurizing CO2 gas into the solution obtained in step (i), and subsequently adding a salt of an alkaline earth metal; and (iii) collecting the resulting precipitate of stabilized amorphous alkaline earth metal carbonate.

3. The method according to claim 2, comprising adding a stabilizer in a stage selected from: (a) before bubbling or pressurizing CO2 gas into the solution obtained in step (i), (b) after adding the salt of the alkaline earth metal, or (c) both (a) and (b).

4. The method according to claim 1, wherein the method comprises: (i) dissolving an alkali in an aqueous solution, wherein the resulting solution has a pH equal to or higher than 8; (ii) adding the salt of the alkaline earth metal to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas into the solution, (iii) collecting the resulting precipitate of stabilized amorphous alkaline earth metal carbonate.

5. The method according to claim 4, comprising adding a stabilizer in a stage selected from: (a) together with the addition of the salt of the alkaline earth metal; (b) before bubbling or pressurizing CO2 gas; or (c) both (a) and (b).

6. The method according to claim 1, comprising the following steps: (i) dissolving an alkali and a stabilizer in an aqueous solution; (ii) bubbling or pressurizing CO2 gas into the solution obtained in step (i), and subsequently adding a salt of an alkaline earth metal and optionally adding a stabilizer to the solution; (iii) optionally adding a stabilizer to the solution obtained in step (ii), and (iv) collecting the resulting stabilized alkaline earth metal carbonate.

7. The method according to claim 1, comprising the following steps: (i) dissolving an alkali and a stabilizer in an aqueous solution; (ii) adding a salt of an alkaline earth metal and optionally adding a stabilizer to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas; (iii) Optionally, a stabilizer is added to the solution obtained in step (ii), and (iv) The resulting stabilized alkaline earth metal carbonate is collected.

8. The method according to any one of claims 6 to 7, comprising adding a stabilizer in step (ii).

9. The method according to any one of claims 6 to 8, comprising adding a stabilizer in step (iii).

10. The method according to any one of claims 1 to 9, wherein the pH of the solution obtained in step (i) is equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11 or equal to or higher than 12.

11. The method according to any one of claims 1 to 10, wherein the precipitation of the alkaline earth metal carbonate is completed within 2 minutes.

12. A method for preparing a stabilized amorphous alkaline earth metal carbonate, the method comprising: Providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding an alkali, at least one stabilizer and an alkaline earth metal to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) continuously collecting the resulting amorphous alkaline earth metal carbonate precipitate, wherein the pH is constantly maintained equal to or higher than 8 throughout the process.

13. The method according to any one of claims 1 to 12, wherein the alkali is selected from hydroxides of alkali metals, ammonia or ammonium hydroxide.

14. The method according to claim 13, wherein the hydroxide of the alkali metal is sodium hydroxide.

15. The method according to claim 13, wherein the alkali is ammonium hydroxide.

16. The method according to any one of claims 1 to 15, wherein the salt of the alkaline earth metal is selected from water-soluble halides, nitrates and sulfates of the alkaline earth metal and their hydrates.

17. The method according to claim 16, wherein the salt of the alkaline earth metal is selected from calcium chloride, calcium bromide, calcium nitrate, magnesium chloride, magnesium sulfate, magnesium nitrate and combinations thereof.

18. The method according to claim 17, wherein the combination of the salts of the alkaline earth metal comprises a combination of a calcium salt and a magnesium salt, and wherein the salts are water-soluble salts.

19. The method according to claim 17, wherein the salt of the alkaline earth metal is calcium chloride.

20. The method according to claim 19, wherein the method comprises adding calcium chloride from 0.03 M to 0.8 M.

21. The method according to claim 17, wherein the salt of the alkaline earth metal is magnesium chloride.

22. The method according to claim 21, wherein the method comprises adding magnesium chloride from 0.04 M to 1 M.

23. The method according to any one of claims 1 to 22, wherein the stabilizer is selected from the group consisting of: polyphosphoric acid / polyphosphate ester / polyphosphate, inorganic polyphosphoric acid / polyphosphate ester / polyphosphate, organic acid, phosphorylated amino acid, phosphorylated, phosphonated, sulfated or sulfonated organic compound, phosphate or sulfate ester of hydroxycarboxylic acid, bisphosphonic acid / bisphosphate ester / bisphosphonate, organic polyphosphoric acid / polyphosphate ester / polyphosphate, polyphosphoric acid / polyphosphate ester / polyphosphate, organic compound having a hydroxyl group, its derivative, protein and any combination thereof.

24. The method according to claim 23, wherein the stabilizer is selected from the group consisting of: triphosphate esters or their salts, phosphoserine, citric acid, sodium tripolyphosphate and citric acid, adenosine triphosphate, adenosine diphosphate, phytic acid, etidronic acid, pyrophosphoric acid / pyrophosphate esters / pyrophosphates, polyphosphoric acid / polyphosphate esters / polyphosphates, hexametaphosphoric acid / hexametaphosphate esters / hexametaphosphates, ethanol, its salts and any combination thereof.

25. The method according to claim 24, wherein the stabilizer is sodium tripolyphosphate.

26. The method according to any one of claims 1 to 25, wherein the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11 or equal to or higher than 12 during the entire preparation process.

27. The method according to any one of claims 1 to 26, wherein the concentration of the added base is at least 2 molar equivalents of the concentration of the alkaline earth metal salt.

28. The method according to any one of claims 1 to 27, wherein the total amount of the added stabilizer is from 2 wt% to 15 wt% of the amount of the alkaline earth metal salt.

29. The method according to any one of claims 1 to 28, wherein the reaction is carried out at atmospheric pressure.

30. The method according to any one of claims 1 to 28, wherein the reaction is carried out at a pressure from 1 bar to 60 bar.

31. The method according to any one of claims 1 to 30, wherein the reaction is carried out at ambient temperature.

32. The method according to any one of claims 1 to 31, wherein collecting the stabilized amorphous alkaline earth metal carbonate comprises filtering and drying the precipitate of the obtained stabilized amorphous alkaline earth metal carbonate.

33. The method according to claim 1, comprising the following steps: (i) Dissolving a base and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the obtained aqueous solution is 8 or greater; (ii) Bubbling or pressurizing CO2 into the solution obtained in step (i), and subsequently adding CaCl2 to the solution and optionally adding sodium tripolyphosphate as a stabilizer; (iii) Optionally adding sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) Collecting the obtained stabilized amorphous calcium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of CaCl2, and optionally wherein CaCl2 is selected from anhydrous CaCl2, CaCl2 monohydrate and CaCl2 dihydrate.

34. The method according to claim 1, comprising the following steps: (i) Dissolving a base and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the pH of the obtained aqueous solution is 8 or greater; (ii) Adding CaCl2, and subsequently bubbling or pressurizing CO2 gas; (iii) Optionally adding sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) Collecting the obtained stabilized amorphous calcium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of CaCl2, and optionally wherein CaCl2 is selected from anhydrous CaCl2, CaCl2 monohydrate or CaCl2 dihydrate.

35. The method according to claim 1, comprising the steps of: (i) dissolving a base and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the resulting aqueous solution has a pH of 8 or greater; (ii) bubbling or pressurizing CO2 gas into the solution obtained in step (i), and subsequently adding MgSO4 to the solution; (iii) optionally adding sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) collecting the resulting stabilized amorphous magnesium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of MgSO4, and optionally wherein MgSO4 is anhydrous MgSO4 or MgSO4 heptahydrate.

36. The method according to claim 1, comprising the steps of: (i) dissolving a base and sodium tripolyphosphate as a stabilizer in an aqueous solution, wherein the resulting aqueous solution has a pH of 8 or greater; (ii) adding MgSO4 and optionally sodium tripolyphosphate as a stabilizer to the solution obtained in step (i), and subsequently bubbling or pressurizing CO2 gas into the solution; (iii) optionally adding sodium tripolyphosphate as a stabilizer to the solution obtained in step (ii), and (iv) collecting the resulting stabilized amorphous magnesium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to at least 2 equivalents of MgSO4, and optionally wherein MgSO4 is anhydrous MgSO4 or MgSO4 heptahydrate.

37. The method according to any one of claims 33 to 36, comprising adding the stabilizer in step (iii).

38. The method according to any one of claims 33 to 37, wherein the base is selected from NaOH and NH4OH and is added in an amount equal to 2 or 3 molar equivalents of CaCl2 or MgSO4.

39. The method according to claim 12, wherein the method is for preparing stabilized amorphous calcium carbonate and comprises: Providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding a base, sodium tripolyphosphate and calcium chloride to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) continuously collecting the resulting amorphous calcium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount of at least 2 molar equivalents of calcium chloride, and wherein the pH is constantly maintained equal to or higher than 8 throughout the process.

40. The method according to claim 12, wherein the method is for preparing stabilized amorphous magnesium carbonate and comprises: Providing an aqueous solution having a pH equal to or higher than 8, and: (i) continuously adding a base, sodium tripolyphosphate and magnesium sulfate to the aqueous solution, (ii) continuously bubbling or pressurizing CO2 gas into the solution, and (iii) continuously collecting the resulting amorphous magnesium carbonate, wherein the base is selected from NaOH and NH4OH and is added in an amount of at least 2 molar equivalents of magnesium sulfate, and wherein the pH is constantly maintained equal to or higher than 8 throughout the process.

41. The method according to any one of claims 33 to 40, wherein the pH is maintained at a value equal to or higher than 8, equal to or higher than 9, equal to or higher than 10, equal to or higher than 11 or equal to or higher than 12 throughout the preparation process.

42. The method according to any one of claims 33 to 40, wherein the pH is maintained at a value between 8 and 13 throughout the preparation process.

43. A stabilized amorphous alkaline earth metal carbonate prepared by the method according to any one of claims 1 to 42.

44. Use of the stabilized amorphous alkaline earth metal carbonate according to claim 43 in agriculture and veterinary medicine.

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