Magnesium: Fused Carnallite Electrolysed in an Iron Pot

Magnesium is made by passing a current through molten chlorides. Thorpe (1912) gives Borchers's process: carnallite and salt dried and fused in an iron pan, cleaned with sawdust and ammonium chloride, then electrolysed in an iron pot that is itself the cathode, with a carbon anode in a porcelain sleeve that leads off the chlorine. The buttons are liquated under fresh carnallite and cast into ingots. Chlorine is poisonous: outdoors, respirator. The picture: magnesium ingots and coiled sheet (CSIRO, Wikimedia Commons).