Comparison of the Preparation Process of Rare Earth Oxides from the Water Leaching Solution of Waste Nd-Fe-B Magnets’ Sulfate Roasting Products

The new process developed here consisting of sulfurization roasting transformation and water immersion can effectively realize the separation rare earth elements (REEs) impurities from spent Nd-Fe-B magnets. For industrial application process, it is critical to determine how economically efficiently prepare oxide (RExOy) products with higher purity obtained leaching solution. Therefore, according sulfate (RE2(SO4)3) solution characteristics, oxalic acid precipitation–calcination method, sodium carbonate double sulfates precipitation–alkali conversion–calcination method were optimized compared. results show that recovery efficiency REE via 99.44%, RExOy 99.83% under optimal technological conditions. However, cost precipitation higher. relatively complicated, REEs 97.95%, 98.04%. are 99.12% 98.33%, respectively. Moreover, recycling lowest among three processes for preparing RExOy, so has potential. magnets in this research provide theoretical guidance innovation as secondary resources.