Production of Aluminium

1. Mine the bauxite ore (a mixture of Al2O3 and SiO2 as well as other impurities such as Fe2O3)
2. Purify the ore by dissolving it in sodium hydroxide solution. This dissolves the alumina (aluminium oxide) which is amphoteric but not the basic impurities g. Fe2O3
3. At the aluminium smelter, the alumina is dissolved in cryolite (Na3AlF6) because this gives the mixture a much lower melting temperature (900 °C) and it conducts electricity better. The mixture is 95% alumina and 5%
4. Large amounts of electrical energy are passed through the mixture. The anodes are carbon rods. The cathode lining is graphite in steel casing. The passing of electric current causes electrolysis to

5. The molten aluminium is poured into ingots and used for many