Carbothermic Reduction of Alumina and Aluminous Ores and Effects of Several Additional Materials (Studies on the Production of Crude Aluminum Alloy by the Direct Reduction of Aluminous Ores (IV)

抄録

The carbothermic reduction of Al₂O₃ and mixtures of Al₂O₃ with Fe₂O₃, NiO, Cu and SiO₂ was studied in argon and CO atmosphere, respectively. Furthermore, the reduction of bauxite and colloidal earth available for the direct reduction of aluminum was also examined.
When the mixture of Al₂O₃/C=1/3 was heated for 30 min in argon, Al₄O₄C and Al₄C₃ were found at 1700° and 1900°C respectively, and Al was observed at 1950°C. In addition, the decrement of total oxygen was measured by activation analysis to investigate the reduction process.
Under a CO atmosphere, Al₄O₄C was not found at all and Al₄C₃ was formed at 1900°C, but Al was not found even at 1950°C. When Fe₂O₃, NiO, and Cu were added to a mixture of Al₂O₃ and carbon respectively, aluminum alloys began to be formed in the range from 1600° to 1700°C in all atmospheres, but intermediate substances such as Al₄O₄C and Al₄C₃ were not observed.
Prior to the formation of Al–Si alloys, the reaction of the Al₂O₃–SiO₂–C system in argon showed a simultaneous change of Al₂O₃–C and SiO₂–C systems.
In case of bauxite and colloidal earth, aluminum alloys were formed at 2000°C in argon, and the addition of NiO to bauxite formed aluminum alloys above 1700°C.