METHOD FOR RECOVERING RARE EARTH METALS FROM SOLID MINERALS AND/OR BY-PRODUCTS OF SOLID MINERAL PROCESSING

摘要

The invention relates to a technique for recovering rare earth metals from solid minerals and also from by-products of solid mineral processing. The method for recovering rare earth metals involves the acid leaching of solid minerals and solid mineral processing by-products, ground to less than 100 μm, using a mixture of sulphuric acid and nitric acid in a ratio ranging from 6:1 to 1:1 parts by weight, wherein the concentration of the acid mixture is less than 15 wt% and the liquid-to-solid ratio is from 2:1 to 6:1 parts by weight. During leaching, a pulsed vacuum action is applied throughout the entire process of converting rare earth metal compounds into a solution, and a residue of residual solid mineral and solid mineral processing by-products is obtained. This residue of solid minerals and solid mineral processing by-products is separated from the leaching solution. The rare earth metals are separated from the leaching solution using an ion exchange filter or a membrane filter. The result is a simplified method and a greater degree of rare earth metal recovery into solution from both phosphogypsum and solid minerals containing rare earth metals.