EXTRACTION OF RARE EARTH METALS FROM NdFeB USING SELECTIVE SULFATION ROASTING

摘要

Sulfuric acid baking allows for the selective extraction of rare earth metals from scrap Nd2Fe14B magnets. This process has the advantage of making the high-value rare earth metals water soluble while converting the contained iron, around 70% of the magnet's mass, into stable and insoluble iron (III) oxide, eliminating the need for separating and precipitating iron from solution. The process also has the advantage of safely disposing of metalworking fluid contained in rare earth magnet machine waste, a troublesome contaminate from technical and environmental perspective.

主权项

1. A method for extracting rare earth metals from a rare earth containing material, comprising:
mixing the rare earth containing material with an acid and water to form a slurry, wherein the rare earth containing material comprises at least one rare earth metal and at least one other metal; roasting the slurry under oxidizing conditions at temperatures between about 200° C. and about 900° C. to form a baked mixture and an off gas; leaching the baked mixture in an aqueous solution to form a liquid leaching product comprising at least one soluble rare earth ion, and a solid leaching residue comprising at least one other insoluble metal oxide; and separating the at least one soluble rare earth ion from the liquid leaching product by precipitation.