Solid State Deoxidation of Some Rare Earth Metals and Reduction of Their Interstitial Impurity Concentrations by Electron Beam Melting

Recycling of Rare Earth Magnet Waste by Removing Rare Earth Oxide with Molten Fluoride

“…Kamihira et al tried the deoxidation by using calcium metal as a deoxidation agent. 18) 830 ppm oxygen decreased to 205 ppm by the processing in a calcia crucible at 1143 K for 18 h. However, contamination by calcium is concerned in the method due to the direct contact of calcium with neodymium although the calcium concentration in neodymium after the deoxidation was not described in the report. Sano et al removed oxygen by using the formation of oxyfluoride in the same manner to the present study.…”

Hydrogen in-situ refining method for preparing high purity gadolinium

“…Upon distillation, the metallic impurities can be easily removed by evaporation, and their concentrations can be reduced to several mass ppm [6,7]. However, it is of great difficulty to remove the non-metallic impurities, especially oxygen and nitrogen [8,9], because of their strong affinity with Gd. Moreover, the reduced metals are vulnerable to be contaminated by the trace gases in these processes.…”