Recycling. Fundamental study on the recycling of rare earth magnet. (2nd Report). Recovery of Samarium and Neodymium from Rare Earth Magnet Scraps by Fractional Crystallization Method.

Recovery of Samarium and Neodymium from rare earth magnet scraps which contain-30% of Sm or Nd and 50-60% of Co or Fe was examined by the fractional crystallization of their sulfates. The results are summarized as follows: 1) When H2SO4was added into the nitric acid solution containing Sm and Co, the solubility of Sm decreased and Sm sulfate hydrate preferentially crystallized. 2) Samarium sulfate hydrate of 96.5% purity with recovery rate 87.1% was obtained from Sm Co5magnet scrap by the fractional crystallization. Effective results were also obtained when Sm2 (Co, Fe, Cu, Zr) 17 was examined similarly. 3) The addition of ethanol into the sulfuric acid-nitric acid solution containing Nd and Fe was proved to be effective for the decrease of solubility and fractional crystallization of Nd. 4) Neodymium sulfate hydrate of 96.8% purity with recovery rate 97.1% was obtained from Nd-Fe-B magnet scrap by the fractional crystallization of metal sulfates with addition of ethanol as well as H2S04.