Patent ID: 7687046

Claim:
A method of preparing a phosphoric acid salt, comprising at least one attack on phosphate ore by an aqueous solution of hydrochloric acid having an HCl concentration of no more than 10% by weight, with the formation of an attack liquor, said attack comprising a dissolving of the phosphate of the ore in said aqueous solution of hydrochloric acid to achieve a yield of attack greater than 80% by weight, expressed as P 2 O 5 , with the obtained attack liquor containing this dissolved phosphate in the form of phosphate ions and having a normalized molar ratio of HCl to Ca of between 0.6 and 1.3 and a free acidity of at least 63%, a first separation, in the attack liquor, between an insoluble solid phase containing impurities and separated aqueous phase, containing in solution said phosphate ions, chloride ions and calcium ions, a neutralization of the said separated aqueous phase by the addition of a calcium compound in order to form, with phosphate ions contained in this aqueous phase, a calcium phosphate insoluble in water, which precipitates, and a second separation, in the said neutralised aqueous phase, between a liquid phase and a precipitated solid phase based on the said calcium phosphate insoluble in water.