METHOD FOR COMPLEX PROCESSING OF PHOSPHOGYPSE Russian patent published in 2021 - IPC C22B3/04 C22B59/00 C01F11/18 

FIELD: chemical industry.

SUBSTANCE: invention relates to the chemical industry, in particular to the processing of phosphogypsum, a large-tonnage by-product of the production of phosphoric acid by the sulfuric acid method, containing valuable chemicals such as calcium and rare earth metals. The method includes processing phosphogypsum with 2-3 mol/l potassium carbonate solution, with a ratio of w: t from 1600 to 1800, in terms of the amount of REE oxides in phosphogypsum. The process is carried out for 4-5 hours at 100-110°C to obtain solid calcium carbonate. The liquid phase is directed to the stage of separation of REE compounds by precipitation from the solution when it is cooled or by sorption on anion-exchange resins. A commercial product is obtained in the form of a mixture of REE compounds and a liquid phase of a sulfate-carbonate solution, which is crystallized to obtain potassium sulfate. The potassium carbonate solution is sent to the phosphogypsum conversion stage.

EFFECT: increased efficiency of complex processing of phosphogypsum.

1 cl, 3 dwg, 6 ex