Abstract: The present invention relates to a method for producing rare-earth metals (REM) compounds by complex processing of apatite, in particularly to a method for concentrating rare-earth metals (REM) in phosphogypsum, where to a process of decomposition of the REM containing raw phosphate material with sulphuric acid, a sodium salt in the amount of 0.25-5.0 kg in terms of Na2O or a potassium salts in the amount of 0.25-5.0 kg in terms of K2O or a mixture thereof in the amount of 0.25-5 kg in terms of Na2O and K2O to 1 kg of REM (in terms of Ln2O3 present in raw phosphate material) is added. The yield of REM transfer into phosphogypsum is up to 98%.

Abstract: The present invention relates to a method for recovery of rare earth metals (REM) from diluted aqueous acidic solutions comprising steps of liquid-phase extraction of REM into an organic phase and re-extraction of REM from the organic phase. The re-extraction is carried out by precipitation of REM as a solid phase in the form of a poorly soluble salt of a strong acid (pKa<0). Recovery of REM into the concentrate is up to 99% in the course of one stage of the re-extraction.

Abstract: The present invention relates to a method for complex processing of apatite concentrate resulting in producing concentrate of rare earth metals (REM) and plaster from phosphogypsum, a waste of sulphuric acid technology for producing phosphoric acid from apatite. The method comprises leaching of REM into solution by recrystallization of hemihydrate or anhydrite of calcium sulphate into dihydrate of calcium sulphate with a soluble calcium salt at concentrations of 0.075-3.75 M (in terms of Ca2+) and strong acid (pKa0) at a concentration of 0.2-8.0 M (in terms of H+). Recovery of REM into solution is up to 98%, the residual content of impurities of phosphorus, fluorine and alkali metals in dihydrate of calcium sulphate does not exceed 0.3 wt. %, 0.1 wt. %, 0.05 wt. %, respectively.

Abstract: The present invention relates to a method for complex processing of apatite concentrate resulting in producing concentrate of rare earth metals (REM) and plaster from phosphogypsum, a waste of sulphuric acid technology for producing phosphoric acid from apatite. The method comprises recrystallization of hemihydrate or anhydrite of calcium sulphate into dihydrate of calcium sulphate in the presence of a soluble calcium salt at concentrations of 0.075-3.75 M (in terms of Ca2+) at subacidic conditions (pH>1), and dissolution with strong acid (pKa<0) at a concentration of 0.2-8.0 M (in terms of H+). Recovery of REM into solution is up to 95%, the residual content of impurities of phosphorus, fluorine and alkali metals in dihydrate of calcium sulphate does not exceed 0.3 wt. %, 0.1 wt. %, 0.05 wt. %, respectively.

Abstract: The present invention relates to a method for complex processing of apatite concentrate resulting in producing concentrate of rare earth metals (REM) and plaster from phosphogypsum, a waste of sulphuric acid technology for producing phosphoric acid from apatite. The method comprises leaching of REM into solution by recrystallization of hemihydrate or anhydrite of calcium sulphate into dihydrate of calcium sulphate with a soluble calcium salt at concentrations of 0.075-3.75 M (in terms of Ca2+) and strong acid (pKa0) at a concentration of 0.2-8.0 M (in terms of H+). Recovery of REM into solution is up to 98%, the residual content of impurities of phosphorus, fluorine and alkali metals in dihydrate of calcium sulphate does not exceed 0.3 wt. %, 0.1 wt. %, 0.05 wt. %, respectively.

Abstract: The present invention relates to a method for complex processing of apatite concentrate resulting in producing concentrate of rare earth metals (REM) and plaster from phosphogypsum, a waste of sulphuric acid technology for producing phosphoric acid from apatite. The method comprises recrystallization of hemihydrate or anhydrite of calcium sulphate into dihydrate of calcium sulphate in the presence of a soluble calcium salt at concentrations of 0.075-3.75 M (in terms of Ca2+) at subacidic conditions (pH>1), and dissolution with strong acid (pKa<0) at a concentration of 0.2-8.0 M (in terms of H+). Recovery of REM into solution is up to 95%, the residual content of impurities of phosphorus, fluorine and alkali metals in dihydrate of calcium sulphate does not exceed 0.3 wt. %, 0.1 wt. %, 0.05 wt. %, respectively.

Abstract: The present invention relates to a method for producing rare-earth metals (REM) compounds by complex processing of apatite, in particularly to a method for concentrating rare-earth metals (REM) in phosphogypsum, where to a process of decomposition of the REM containing raw phosphate material with sulphuric acid, a sodium salt in the amount of 0.25-5.0 kg in terms of Na2O or a potassium salts in the amount of 0.25-5.0 kg in terms of K2O or a mixture thereof in the amount of 0.25-5 kg in terms of Na2O and K2O to 1 kg of REM (in terms of Ln2O3 present in raw phosphate material) is added. The yield of REM transfer into phosphogypsum is up to 98%.

Abstract: The present invention relates to a method for recovery of rare earth metals (REM) from diluted aqueous acidic solutions comprising steps of liquid-phase extraction of REM into an organic phase and re-extraction of REM from the organic phase. The re-extraction is carried out by precipitation of REM as a solid phase in the form of a poorly soluble salt of a strong acid (pKa<0). Recovery of REM into the concentrate is up to 99% in the course of one stage of the re-extraction.

Abstract: The present invention relates to a method for purification of acidic solutions of salts, in particularly those formed in the course of complex apatite processing yielding rare-earth metal (REM) concentrate from phosphorus, fluorine and alkali metals impurities comprising precipitation of phosphorus and fluorine in the form of calcium phosphates and fluorides and alkali metals in the form of silicofluorides of alkali metals. In some embodiments before the precipitation of calcium phosphates and fluorides and silicofluorides of alkali metals, acid is selectively extracted into an organic extractant, and after the precipitation of calcium phosphates and fluorides and silicofluorides of alkali metals the acid is may be re-extracted from the extractant into an aqueous solution. Methods allow for the removal of phosphorus, fluorine and alkali metals impurities and regeneration of the acid.