METHOD OF COMPLEX PROCESSING PHOSPHOGYPSUM Russian patent published in 2017 - IPC C22B59/00 C22B3/08 

FIELD: chemistry.

SUBSTANCE: invention is designed to extract rare-earth elements (REE) from dump phosphogypsum (PG) and to produce a gypsum binder. Sulfuric acid leaching of the REE from the pulp of FG is carried out in the circulation mode with electrochemical and cavitation activation. The pulp is separated by filtration on the first cake and the productive solution of the REE, the oxalates of the REE are precipitated with a solution of oxalic acid. One part of the solution is filtered to produce the second cake, combined with the first cake and sent to the production of gypsum. The other one is used as a circulating solution. The FG is prepared by crushing and soaking in a recycled solution based on the filtrate of the spent product solution. From the prepared FG, the REE is leached by portions.

EFFECT: method allows to increase the completeness of processing, to eliminate the need for sharpening solutions of sulfuric acid during the leaching process, to reduce the residual concentration of fluoride ion below the maximum allowable concentrations, that will provide savings of reagents in the neutralisation of dumps.

9 cl, 3 dwg