PHOSPHATE RARE-EARTH CONCENTRATE PROCESSING METHOD Russian patent published in 2009 - IPC C01F17/00 C22B59/00 C22B3/00 

FIELD: chemistry.

SUBSTANCE: invention can be used in chemistry and metallurgy. Phosphate rare-earth concentrate processed with nitric acid is heated with oxalic acid in plenty. Rare-earth elements (REE) oxalate deposition is separated from mother liquor containing residual quantity of oxalic acid, washed and treated with potash alkali in plenty 5-50% surplus in stoichiometry ratio per oxalate-ions so that potassium oxalate solution and REE hydroxide depositions are formed. After REE hydroxide depositions are separated, potassium oxalate solution is delivered back to phosphate concentrate processing stage. REE hydroxide depositions are exposed to heat treatment at 100-150°C to produce collective concentrate of REE hydroxides, or at 250-500°C to oxidise cerium to cerium (IV). Then deposition is pulped in water at "Т:Ж"=1:4-8 and processed with nitric acid consumed as 0.6-0.8 wt fractions of 100% HNO₃ per 1 wt fraction of REE oxides with REE transfer, except for Ce (IV), to solution. Cerium-containing deposition is separated. Potassium oxalate solution is concentrated with oxalic acid in residual quantity contained in mother liquor, and treated with neutral extractant, principally with tributylphosphate or triisoamylphosphate. Oxalic acid in residual quantity is transferred to extract, re-extracted with potassium oxalate solution. Oxalic acid consumption and thermal processing power inputs are reduced. Selective cerium separation from total REE is provided. Produced cerium concentrate contains CeO₂ 96.5-97.8 wt %.

EFFECT: reduced oxalic acid consumption and thermal processing power inputs, provided selective cerium separation from total rare-earth elements.

2 cl, 5 ex