Patent ID: 9371230
Filing Date: 2016-06-21
CPC Classification: C01B

Claim Text:
1. A method for producing phosphoric acid, comprising attack in an aqueous medium of phosphated rock with sulfuric acid at a first temperature comprised between 70 and 90° C., with formation of a first slurry of calcium sulfate dihydrate crystals suspended in an acid aqueous phase, the acid aqueous phase of this slurry having a free P conversion of this first slurry by heating to a temperature above 90° C., with solubilization of the calcium sulfate dihydrate crystals and recrystallization of the solubilized calcium sulfate giving rise to a second slurry formed with calcium sulfate hemihydrate crystals suspended in an aqueous phase based on phosphoric acid, and separation in said second slurry between a production phosphoric acid, having a P