High Temperature Decarbonization of Neodymium Sesguisulfide by Hydrogen, Hydrogen Sulfide and Ammonia

The removal of carbon impurity from Nd2S3 has been studied by heating in the gases of 4 % H2/N2, H2S and NH3. When the sulfide containing 1,200 mass ppm carbon impurity was heated in 4 % H2/N2 or H2S at 1,600 'С for 1 h, the carbon content decreased to 600 mass ppm. With NH3 gas, the carbon content decreased to 850 mass ppm by heating at a lower temperature of 1,000 “C for 1 h. Prolonged heating for 5 h resulted in further decrease of carbon content to 600 ppm.