Abstract: A point feeder for metering powder materials, for example aluminum oxide, to a Hall-Heroult electrolysis cell includes a vertical tube and a horizontal tube which are joined so that they form substantially an L-shaped channel with a material input at an upper end of the vertical tube and a material output at an end of the horizontal tube. The vertical tube is provided with a nozzle device which has one or more downward-facing holes which allow air to penetrate in the form of pulsed air flows to the lower part of the vertical tube and to the whole of the horizontal tube.

Abstract: Magnesium is electrolytically produced from a salt melt comprising magnesium chloride by the use of an electrolyzer having at least one electrolysis compartment and at least one metal separating compartment separated from the electrolysis compartment by a partition wall. Magnesium chloride is fed in solid form in a direction counter current to the flow of chlorine gas liberated during electrolysis to a melting room or chamber in the electrolysis compartment arranged such that contact between the magnesium chloride and the anodes of the electrolyzer is avoided. Flow patterns are produced in the melt to ensure that sludge forming impurities in the fed magnesium chloride are continuously removed from the electrolysis compartment to the metal separating compartment.