Patent ID: 9255006
Filing Date: 2016-02-09
CPC Classification: C01B

Claim Text:
1. A method for producing phosphoric acid, comprising: an attack in an aqueous medium of phosphate rock by means of 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 a 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 of hemihydrate calcium sulfate crystals suspended in an aqueous phase based on phosphoric acid, and a separation in the second slurry between a production phosphoric acid, having a free SO