METHOD OF PROCESSING PHOSPHATE RARE-EARTH CONCENTRATE ISOLATED AT NEUTRALIZATION OF NITROGEN-PHOSPHATE SOLUTION OBTAINED AFTER APATITE OPENING WITH NITRIC ACID Russian patent published in 1997 - IPC

FIELD: chemical technology of rare-earth elements, fertilizers. SUBSTANCE: apatite is treated with nitric acid, nitrogen-phosphate solution is neutralized, phosphate rare-earth concentrate is dissolved in nitric acid and insoluble residue is separated. Residue is washed with nitrogen-phosphate solution after isolation of part of calcium nitrate tetrahydrate from it. Solution consumption at washing is 100-710 mas. p. per 1 mas. p. insoluble residue. After washing solution is fed to neutralization of nitrogen-phosphate solution. Method is used for utilization of rare-earth elements at apatite processing to complex fertilizers. EFFECT: improved method of processing. 3 cl, 1 tbl