Abstract
Magnesium chloride for electrolysis to magnesium in a fused-salt bath is made by reacting seawater with milk of lime to precipitate magnesium hydroxide, separating the latter from the barren seawater, dissolving the hydroxide in hydrochloric acid, and crystallizing and drying the compound mgcl2.1.5H2o. Solar evaporation of Great Salt Lake brine, followed by spray drying, also is practiced. Dolomite may be calcined and ground to a fine powder to be mixed with ferrosilicon for reduction to magnesium in vacuum retorts by a nonelectrolytic process. Alumina for smelting to aluminum in hall- heroult cells is prepared from bauxite by pressure digestion with strong naoh solution, thickening, and filtration to separate a waste "red mud," and crystallization of al2o3.3H2o in the presence of seed crystals. The al2o3.3H2o then is calcined to al2o3. The Bureau of Mines and other research on the recovery of alumina from nonbauxitic aluminous materials is discussed, and possible applications of acid leaching, alkaline sinter-caustic leaching, and carbochlorination processes to lunar materials are briefly evaluated.
