公开(公告)号：US20190322540A1

公开(公告)日：2019-10-24

申请号：US16312906

申请日：2017-06-22

Applicant: PRAYON TECHNOLOGIES

Inventor： Thomas HENRY ,  Tibaut THEYS

IPC: C01F11/46 ,  C01B25/231 ,  C01B25/32 ,  C04B11/26

Abstract: A method for preparing calcium sulphate comprising a production of DCP by the attack of a source of phosphate by an acid, a digestion of the isolated DCP by the sulphuric acid under conditions giving rise to the formation of a first slurry of gypsum suspended in an acidic aqueous phase having a content of free SO3 equal to or less than 1.5% and a content of free P2O5, a conversion of at least part of said first slurry by heating to a temperature greater than 80° C. and potentially by adding sulphuric acid, with solubilisation of the gypsum crystals and recrystallisation of the solubilised calcium sulphate in a second slurry of α-calcium sulphate hemihydrate crystals suspended in an aqueous phase based-on phosphoric acid, wherein the content of free SO3 is less than 10% by weight, and a separation between said aqueous phase and a filter cake based on particularly pure α-calcium sulphate hemihydrate.

公开(公告)号：US20190322530A1

公开(公告)日：2019-10-24

申请号：US16311626

申请日：2017-06-27

Applicant: PRAYON TECHNOLOGIES

Inventor： Tibaut THEYS ,  Thomas HENRY

IPC: C01B25/32

Abstract: This present invention disclosure relates to a method for the preparation of calcium monohydrogen phosphate comprising an etching in an aqueous medium, during a predetermined time period, of a phosphate source with an acid with formation of a pulp comprising an aqueous phase containing calcium phosphate in solution and a solid phase containing impurities, a first separation between said aqueous phase and said solid phase, during a predetermined time period, a neutralization of said aqueous phase at a sufficient pH to obtain a precipitation of said calcium monohydrogen phosphate, a second separation between said aqueous medium and said calcium monohydrogen phosphate, characterized in that said first separation of said step b) is carried out at a filtration rate of at least 0.1 ton of P2O5/√ΔP/m2/day.