Abstract: Apparatus for the continuous vacuum refining of a metal comprising a cylindrical vacuum chamber, containing a stack of a plurality of vertically superposed trays. The trays receive impure molten metal which flows downwardly from tray to tray while impurities are discharged therefrom and flow to shields which surround the trays and condense and discharge the impurities. The metal in the trays is heated to evaporate the impurities therefrom. The heat energy which is imparted to the metal is effected irregularly along the height of the stack of the trays such that the imparted heat energy diminishes in a vertically downwards direction.

Abstract: The present invention relates to apparatus for continuous refining of tin.The apparatus comprises a vacuum chamber accommodating an evaporator which is a vessel with a granulated loose material filling the entire vessel volume to provide a maximum evaporating surface washed by molten metal being refined, with the vessel side walls being fitted with outlets for the effluence of impurity vapors, referred to hereinafter as volatilized impurities, liberated from said metal evaporating surface, and with the vessel bottom having drains for discharging refined metal from the vacuum chamber.

Abstract: A method of refining crude cadmium by vacuum distillation in which crude cadmium is passed into a reflux condenser in which higher boiling point impurities are condensed together with a portion of pure cadmium vapor, this condensate flowing in counterflow with the crude cadmium vapor. The remaining portion of the pure cadmium vapor is subsequently condensed. The apparatus comprises an inverted U-shaped vacuum chamber having an evaporator and a reflux condenser in one leg and a further condenser in the other leg. A feed pipe for liquid crude cadmium enters the one leg adjacent the evaporator and a residue outlet pipe leaves the one leg, the feed pipe and the residue pipe being arranged so that no back-flow takes place from the residue pipe to the feed pipe. An outlet pipe for the refined cadmium issues from the other leg of the vacuum chamber.