METHOD FOR EXTRACTION SEPARATION OF RARE-EARTH METALS FROM NITRATE SOLUTIONS Russian patent published in 2016 - IPC C22B59/00 C22B3/38 

FIELD: chemistry.

SUBSTANCE: method for separation of rare-earth metals from solutions includes preparing rare-earth metal nitrate solutions by dissolving rare-earth metal carbonates in nitric acid; extracting rare-earth metal cations in tributyl phosphate and separating the extracted rare-earth metals by re-extraction. Before preparing rare-earth metal nitrate solutions, the rare-earth metal carbonates are pre-oxidised by blowing with hot air at temperature 300-350°C. The oxidised rare-earth metal carbonates are dissolved in 60-70% nitric acid solution at final temperature of the solution not higher than 100-120°C, followed by extraction of rare-earth metals in tributyl phosphate with total content of rare-earth metal oxides of up to 600-650 g/l in the initial nitrate solution and re-extraction with hydrogen peroxide solution in nitric acid. To obtain cerium oxide, cerium oxalate is precipitated after re-extraction and then calcined at 900°C.

EFFECT: simple technique, high separation coefficient of cerium and other rare-earth metals and obtaining high-quality cerium.

7 cl, 2 tbl, 2 ex