EXTRACTION OF RARE-EARTH ELEMENTS FROM HARD MATERIALS CONTAINING RARE-EARTH METALS Russian patent published in 2014 - IPC C22B59/00 C22B3/06 

FIELD: metallurgy.

SUBSTANCE: proposed method comprises acid leaching of solid materials ground to at least 100 mcm by the mix of sulphuric and nitric acids at their ratio of 6:1 to 1:1 parts by weight and concentration of the mix of acids lower than 15 wt % and F:S ratio varying from 2:1 to 6:1 parts by weight. At acid leaching vacuum-pulse effects are applied during the entire process of rare-earth elements conversion into solution and precipitation of remained solid material. Obtained precipitate of solid fossil and man-made materials is separated from leaching solution. Separation of rare-earth elements from leaching solution is performed with the help of ion-exchange or membrane filter.

EFFECT: simplified process, higher yield.

3 cl, 2 tbl, 2 ex