Abstract: A process for producing KNO3 from polyhalite to is disclosed. In a preferred embodiment, the process comprises steps of (a) contacting polyhalite with HNO3; (b) adding Ca(OH)2 to the solution, thereby precipitating as CaSO4 at least part of the sulfate present in said solution; (c) precipitating as Mg(OH)2 at least part of the Mg2+ remaining in said solution by further addition of Ca(OH)2 to the remaining solution; (d) concentrating the solution, thereby precipitating as a sulfate compound at least part of the sulfate remaining in solution; (e) separating at least part of the NaCl from the solution remaining; and (f) crystallizing as solid KNO3 at least part of the K+ and NO3-contained in the solution. The process enables direct conversion of polyhalite to KNO3 of purity exceeding 98.5% and that is essentially free of magnesium and sulfate impurities.

Abstract: A mixture suitable for use in forming a magnesium silico-phosphate cement is disclosed. The mixture comprises particles of MgO at least partially coated with an additive adapted to alter the setting time of said cement cast; a phosphate salt or acid chosen that will provide a binder product characterized by the empirical chemical formula MMgPO4.6H2O; and an aggregate phase chosen from the group containing (a) CaSiO3, (b) MgSiO3, (c) SiO2, (d) fly ash, (e) sea sand, and (f) any combination thereof. Coating the MgO particles provides better control of the alteration of the setting time and better physical properties of the set cement. Methods for making the mixture and for preparing a cement cast based on the mixture are also disclosed.

Abstract: A cement mix for preparation of a magnesium silico-phosphate cement (MSPC) with an altered hardening rate is provided. The cement mix comprises on the order of 1% of an [MF6]n? salt or acid. Upon addition of water, the mix produces a final set cement that has similar physical properties to those of a cement prepared from a mix lacking the additive, but with a significantly altered setting time. In some embodiments of the invention, the additive is provided in the form of a coating for the MgO component of the mix. In preferred embodiments, H2TiF6, Na2TiF6 and/or K2TiF6 are used as retarders, while K3AlF6 is used as an accelerant. Other embodiments use M?nMF6 compounds wherein M? is an alkali metal, an alkaline earth metal, or H, and M is chosen from inter alia Ti (n=2), Zr (n=2), P (n=1), Al (n=3), and Sb (n=1).

Abstract: A method for the production of KNO3 from polyhalite is provided. The method comprises steps of decomposing said polyhalite into syngenite, gypsum, and soluble components, treating the solid decomposition products sequentially with HNO3 and Ca basic compound, precipitating the CaSO4 thus formed, and crystallizing the KNO3 from the solution remaining. The method recovers up to 75% of the potassium present in the raw polyhalite as KNO3 and substantially all of the remainder as a potassium magnesium sulfate salt.

Abstract: A method is provided for advantageously altering the rate of hardening of a magnesium silico-phosphate cement (MSPC). Addition of on the order of 1% of an [MF6]n? salt or acid to an MSPC, obtained by adding the salt or acid either directly to the dry mix or to the water used to effect hydraulic hardening of the cement, significantly alters the hardening rate without adversely affecting the physical properties of the final set cement. In preferred embodiments, Na2TiF6 and/or K2TiF6 are used as retardants, while K3AlF6 is used as an accelerant. Other embodiments use M?n-MF6 compounds wherein M? is an alkali metal, an alkaline earth metal, or H, and M is chosen from inter alia Ti (n=2), Zr (n=2), Si (n=2), P (n=1), Al (n=3), and Sb (n=1).

Abstract: A method for the production of KNO3 from polyhalite is provided. The method comprises steps of decomposing said polyhalite into syngenite, gypsum, and soluble components, treating the solid decomposition products sequentially with HNO3 and Ca basic compound, precipitating the CaSO4 thus formed, and crystallizing the KNO3 from the solution remaining. The method recovers up to 75% of the potassium present in the raw polyhalite as KNO3 and substantially all of the remainder as a potassium magnesium sulfate salt.

Abstract: A process for producing KNO3 from polyhalite to is disclosed. In a preferred embodiment, the process comprises steps of (a) contacting polyhalite with HNO3; (b) adding Ca(OH)2 to the solution, thereby precipitating as CaSO4 at least part of the sulfate present in said solution; (c) precipitating as Mg(OH)2 at least part of the Mg2+ remaining in said solution by further addition of Ca(OH)2 to the remaining solution; (d) concentrating the solution, thereby precipitating as a sulfate compound at least part of the sulfate remaining in solution; (e) separating at least part of the NaCl from the solution remaining; and (f) crystallizing as solid KNO3 at least part of the K+ and NO3-contained in the solution. The process enables direct conversion of polyhalite to KNO3 of purity exceeding 98.5% and that is essentially free of magnesium and sulfate impurities.

Abstract: A method is provided for advantageously altering the rate of hardening of a magnesium silico-phosphate cement (MSPC). Addition of on the order of 1% of an [MF6]n? salt or acid to an MSPC, obtained by adding the salt or acid either directly to the dry mix or to the water used to effect hydraulic hardening of the cement, significantly alters the hardening rate without adversely affecting the physical properties of the final set cement. In preferred embodiments, Na2TiF6 and/or K2TiF6 are used as retardants, while K3AlF6 is used as an accelerant. Other embodiments use M?n-MF6 compounds wherein M? is an alkali metal, an alkaline earth metal, or H, and M is chosen from inter alia Ti (n=2), Zr (n=2), Si (n=2), P (n=1), Al (n=3), and Sb (n=1).

Abstract: The present invention pertains to free flowing food additives powders comprising processed fruit juice being loaded on a plant-origin solid support.