METHOD FOR PHOSPHOGYPSUM PROCESSING Russian patent published in 2018 - IPC C22B3/08 C22B59/00 

FIELD: chemistry.

SUBSTANCE: method for phosphogypsum processing involves preliminary granulation of phosphogypsum with sulfuric acid, followed by percolation leaching of the granulated material with a sulfuric acid solution with a concentration of up to 0.1 wt % in the mode of solution recirculation between leaching and sorption stages. Further desorption of thorium and calcium is carried out with an ammonium nitrate solution with a concentration of 80-120 g/l. REE desorption is carried out with an ammonium nitrate solution with a concentration of 240-280 g/l. REE concentrate precipitation is carried out with an ammonium hydroxide solution with a concentration of 150-300 g/l.

EFFECT: increased productivity, efficiency and versatility of phosphogypsum processing and increased content of rare-earth elements in the resulting hydroxide concentrate.

4 cl, 5 tbl