Abstract: A process for recovery of alumina and soda from materials containing sodium aluminosilicates, such as red mud and desilication products, comprises treating said materials with lime at elevated temperature and pressure. In a preferred embodiment of the invention, hydrothermal treatment of red mud with lime is integrated into a Bayer process to improve the overall efficiency of that process.

Abstract: Aluminium-silicon alloys of the following composition by weight:______________________________________ Si 12-15% Cu 1.5-5.5%, preferably 1.5-4% Ni 1.0-3.0% Mg 0.1-1.0% preferably 0.4-1.0% Fe 0.1-1.0% preferably 0.1-0.5% Mn 0.1-0.8% Zr 0.01-0.1% Modifier (preferably Sr) 0.001-0.1% preferably 0.01-0.05% Ti 0.01-0.1% Al Remainder, apart from impurities. ______________________________________Superior properties are obtained by control of growth rate of the solid phase during solidification and the temperature gradient at the solid-liquid interface. The alloys of the invention are suitable for a wide variety of applications, including brake calipers and drums, piston/bore applications in internal combustion engines and a number of other components in engines, compressors and electric motors. A particular application of the alloys of the invention is in aluminium cylinder heads.

Abstract: Removal of iron from aluminous material such as bauxite is effected by treatment with a gas mixture comprising sulphur dioxide and carbon monoxide in a first step, followed by chlorination in a second step whereby ferric chloride is produced and removed by volatilization. Aluminium chloride of low iron content may be obtained from the purified aluminous material by chlorination.