The use of rare earth elements (REEs) in high-tech products such as permanent magnets, phosphorous materials, catalysts, and batteries has raised worldwide demand for these elements. The increasing concerns about rare earth supply and environmental issues in ore extraction, as well as limited resources and national legislation, have resulted in a surge in investigations on REEs recovery from scrap materials. This research represents a part of the recycling strategy of NdFeB magnets, which consists of the production of rare earth element oxides by different methods. In this study, rare earth element oxides were produced by solution combustion technique and traditional precipitation from the leach liquor after the removal of iron. Moreover, comparative studies for determining the purity of rare earth oxide produced by the aforementioned methods were carried out by chemical analyses. Morphological properties and phase content of the produced rare earth oxide were revealed by characterization methods. At last, advantages and disadvantages of the abovementioned methods were listed in terms of the purity and morphological properties of rare earth element oxide.

Keywords: NdFeB recycling, hydrometallurgy, rare earth element oxides, iron precipitation, solution combustion