It is shown that phosphogypsums obtained from the Khibiny apatite concentrate can be purified by percolation leaching with low-concentration sulfuric acid solutions to remove admixtures of fluorides, phosphates, and water-soluble compounds of sodium, with simultaneous transfer of rare-earth element sulfides into solution. The achievable degree of impurity extraction enables use of the purified material as a gypsum raw material for manufacture of gypsum binders and cement. The method is applicable to processing of both currently produced phosphodihydrate, phosphohemihydrate, and mixtures of these and those long stored in dumps.
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Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Resources, Kola Scientific Center, Russian Academy of Sciences, Murmansk oblast, Russia;
