Vacuum distillation of magnesium.

Abstract

An investigation on vacuum distillation of magnesium was carried out to obtain high purity material for basic research use, using a Mg–20%Al electrolytic magnesium (99.93%) base alloy as a raw material. Magnesium vapor was found to be condensed at a region where the temperature ranged from 625 K to 750 K involving steep temperature rise ascribed to the latent heat of condensation. To permit the condensation to occur uniformly on the sleeve, the temperature of the condenser portion was controlled within the above range. Purified magnesium of about 3 kg was obtained from the raw material of 4 kg by a distillation for 86.4 ks at 933 K. Impurities such as Fe, Mn, Si, commonly contained in commercial magnesium, were substantially eliminated by this distillation, resulting in a purity above 99.99% that was significantly increased from that (99.93%) of electrolytic magnesium.