METHOD FOR REMOVING PHOSPHORUS AND CALCIUM RICH IN RARE EARTH FROM PHOSPHORITE CONTAINING RARE EARTH

文件类型：PDF文档
文件大小：762K
A method for removing phosphorus and calcium rich in rare earth from phosphorite containing rare earth through priority leaching by using mixed solution of phosphoric acid and calcium dihydrogen phosphate, mixing phosphorite containing rare earth and cyclical phosphoric acid solution with a solid-liquid ratio of 1 : 2-10, wherein the cyclical phosphoric acid solution contains 15-55 wt% of P2O5, 2-25g/L of Ca2+ and 5-45wt% of effective P2O5; stirring and reacting the mixture at 20-70℃ for 0.5-4 hours; aging for 1-5 hours; and separating the solid and liquid to obtain residue containing enriched rare earth and leaching solution. The leaching solution is mixed with sulfuric acid, and a suitable amount of gypsum residue is added at the same time, wherein mole number of the added sulfuric acid is 0.7-1 time of calcium mole number in the leaching solution, and the amount of the added gypsum residue is 10-100% of the mass of the phosphorite containing rare earth. Recovered phosphoric acid and gypsum residue are obtained by filtering after reaction. Part of recovered phosphoric acid, washing water of the gypsum residue and suitable amount of supplementary water are mixed and returned for leaching as the cyclical phosphoric acid.