METHOD FOR PROCESSING GRINDING WASTES FROM PRODUCTION OF PERMANENT MAGNETS Russian patent published in 2016 - IPC C22B59/00 C22B7/00 C22B3/08 

FIELD: chemistry.

SUBSTANCE: grinding wastes are mixed with concentrated (not less than 92%) sulphuric acid in quantity, necessary for obtaining solid agglomerated product. Then process of solid-phase sulphatisation is carried out at temperature 200-250°C, with further calcination at temperature 650-850°C. Then, leaching of sulphates of rare-earth metals (REM) and other metals with acidified water in percolation columns and extraction of REM from productive solutions by precipitation are carried out. Solid residue of leaching (cake) represents practically pure oxide of trivalent iron.

EFFECT: achievement of high degree of the total REM extraction into solution with minimal transition of iron and other admixtures into solution in form of sulphates.

3 cl, 1 tbl, 2 ex