METHOD OF PROCESSING PHOSPHOGYPSUM Russian patent published in 2013 - IPC C01B25/01 C01B25/00 C05B11/10 C05C3/00 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry, particularly to phosphogypsum processing. The method of processing phosphogypsum involves mixing phosphogypsum and 42% phosphoric acid in the presence of a reagent for maintaining pH in the range of 6.8-7.2 while stirring constantly and separating dicalcium phosphate residue from the liquid phase. The reagent used to maintain pH is aqueous ammonia solution. Components are fed for mixing in the following ratio, wt %: phosphogypsum - 65.0, phosphoric acid - 31.0, aqueous ammonia solution (with respect to ammonia) - 4.0. Mixing is carried out at temperature not higher than 80°C.

EFFECT: use of the invention increases processing depth of phosphogypsum, enables to obtain two commercial products - feed grade dicalcium phosphate and ammonium sulphate, reduces the cost and cuts duration of obtaining the products.

3 cl, 1 tbl, 3 ex