A STUDY OF THE REDUCTION OF DYSPROSIUM OXIDE WITH LANTHANUM AS A METHOD FOR PRODUCING HIGH PURITY DYSPROSIUM METAL Based on a M.S. thesis submitted by Brian Lee Sanden to Iowa State University, Ames, Iowa, August 1973

摘要

An investigation was carried out to evaluate the prep¬aration of dysprosium metal by a reduction-distillation method. Lanthanum metal was used as the reductant.nMaximum yields of the as-reduced metal were typically 70 to 75% when a reduction temperature of 1650°C was used. If the reaction was run long enough to obtain a 50% of theoretical yield a purer product was obtained in a much shorter length of time. The yield did not improve when a reduction was per¬formed at 1750°C.nThe yield of dysprosium metal was rather insensitive to the amount of excess lanthanum reductant used. A 10% stoichio¬metric excess of lanthanum was found to give optimum yields, with no further increase in yield when 20 and 30% excess re¬ductant was used.nThe as-reduced metal product contained typically 1% by weight lanthanum and 1000 ppm by weight oxygen.nWhen the metal was purified by sublimation at 1100 to 1300°C one sublimation lowered the lanthanum level to 650 ppm and the oxygen to 50 ppm. Two additional sublimations yielded a product containing 20 ppm oxygen and 30 ppm or less lantha¬num. A temperature of 1300°C was most desirable since greater sublimation rates were possible with good purification of products.