METHOD OF PROCESSING RARE-EARTH PHOSPHATE CONCENTRATE

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FIELD : chemistry. SUBSTANCE : method of processing a rare-earth phosphate concentrate separated when neutralising a nitric-phosphoric acid solution obtained after breaking down apatite with nitric acid, includes treating rare-earth phosphate concentrate with nitric acid and separating the undissolved residue from the obtained rare-earth element nitrate-phosphate solution. After treatment, the undissolved residue is washed and rare-earth elements are extracted from the rare-earth element solution. The undissolved residue is washed with ammonium nitrate solution with concentration of 40-70 wt % in amount of 25 pts.wt per 1 pts.wt of the undissolved residue. The wash solution is combined with the rare-earth element solution fed for extraction, and the undissolved residue is taken for production of compound fertilisers. EFFECT : high degree of extraction of rare-earth elements from the rare-earth phosphate concentrate while reducing consumption of ammonia at the step of neutralising the nitric-phosphoric acid solution, consumption of nitric acid and hydrogen peroxide when dissolving the rare-earth phosphate concentrate. 3 cl, 3 tbl, 4 ex