Recycling of Neodymium Iron Boron Magnet Scrap

摘要

The U.S. Bureau of Mines investigated methods of separating valuable rare-earthmaterials from Fe in neodymium iron boron (NdFeB) magnet scrap. The best separation of rare earths from bulk NdFeB magnet scrap was obtained by dissolution with H2SO4 followed by precipitation of recyclable rare-earth salts. By precipitating neodymium-alkali sulfate double salts as an intermediate that can be converted to a variety of useful products, many materials-handling and economic disadvantages found with direct precipitation with fluoride or oxalate were avoided. Iron was removed from magnet leach solutions by precipitation as a jarosite, eliminating a major disposal problem.