METHOD FOR RECOVERING RARE-EARTH ELEMENTS FROM A SOLID MIXTURE CONTAINING A HALOPHOSPHATE AND A COMPOUND OF ONE OR MORE RARE-EARTH ELEMENTS

摘要

The present invention relates to a method for recovering rare earth elements from a halophosphate of at least one rare earth element and a solid mixture containing at least one compound, comprising: (a) acid etching the mixture; (b) adding a base that makes the pH at least 1.5; (c) etching the solid of step (b) with soda or kali; (d) acid etching the solid of step (c) until the pH is less than 7, resulting in a liquid phase and a solid phase comprising at least one rare earth salt and separating the solid phase from the liquid phase.