METHOD OF PHOSPHOGYPSUM PROCESSING FOR MANUFACTURE OF CONCENTRATE OF RARE-EARTH ELEMENTS AND GYPSUM Russian patent published in 2012 - IPC C22B59/00 C22B3/08 C22B3/24 

FIELD: metallurgy.

SUBSTANCE: method of phosphogypsum processing involves leaching of phosphogypsum with sulphuric acid solution with change-over of phosphorus and rare-earth elements to the solution, and gypsum residues is obtained, rare-earth elements are extracted from the solution and the gypsum residue is neutralised with the main calcium compound. In addition, leaching is performed with sulphuric acid solution with concentration of 1-5 wt %. After that, rare-earth elements are extracted from the solution by sorption using sulfocationite in hydrogen or ammonia form with further desorption of rare-earth elements with ammonia sulphate solution. After desorption to the obtained strippant there added is ammonia or ammonium carbonate with deposition and separation of hydroxide or carbon-bearing concentrate of rare-earth elements. Extraction of rare-earth elements of medium and yttrium groups to concentrates is 41-67% and 28-51.4% respectively. Specific consumption of neutralising calcium compound per 1 kg of phosphogypsum has been reduced at least by 1.6 times.

EFFECT: obtaining high-quality hydroxide or carbonate concentrate of rare-earth elements.

4 cl, 4 tbl, 4 ex