Method for producing a calcium phosphate salt
AssigneeJesa Technologies LLC
InventorsStephen Wayne Hilakos, Anis Lakhouaja
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Abstract
Methods are disclosed for producing a calcium phosphate salt comprising reacting fluorosilicic acid (FSA) with water and a calcium phosphate source to produce phosphoric acid, calcium fluoride, and silicon dioxide; removing residual solids; performing a first stage precipitation wherein the phosphoric acid generated previously is reacted with a calcium source and water to remove residual fluoride; and performing a second stage precipitation wherein the phosphoric acid generated previously is reacted with a calcium source and water to isolate the product calcium phosphate salt, having a low level of impurities.
Claims20
A method for producing di-calcium phosphate (DCP) comprising:
- (a) reacting fluorosilicic acid (FSA) with water and a calcium phosphate source to produce phosphoric acid, calcium fluoride, and silicon dioxide;
- (b) removing residual solids;
- (c) performing a first stage precipitation wherein the phosphoric acid generated in step (a) is reacted with a calcium source and water to remove residual fluoride;
- and
- (d) performing a second stage precipitation wherein the phosphoric acid from step (c) is reacted with a calcium source and water to produce the product DCP.
A method for producing a calcium phosphate salt comprising:
- (a) digesting a first calcium phosphate source using an aqueous solution of fluorosilicic acid (FSA), to form a liquor consisting of an aqueous phase comprising phosphate ions in solution, and a first insoluble solid phase containing impurities;
- (b) separating the aqueous phase comprising phosphate ions in solution from the first insoluble solid phase containing impurities;
- (c) performing a first stage precipitation wherein said aqueous phase comprising phosphate ions in solution is neutralized with a calcium source at a pH sufficient to precipitate any excess fluoride in solution;
- and
- (d) performing a second stage precipitation wherein said aqueous phase comprising phosphate ions in solution is neutralized with a calcium source at a pH sufficient to produce the product calcium phosphate salt.
Dependencies are inferred from the claim text.