The extraction of aluminum was carried out by the subchloride process. The source material was the crude aluminum alloy prepared from colloidal earth and bauxite by the use of a 70 kVA electric furnace.
The extraction ratio of aluminum increased as the size of alloy particles is smaller and the supply of aluminum trichloride is larger, and reached more than 90% at 1300°C. Furthermore, its ratio depended not only on the aluminum content in the alloy but also on the Fe/Si ratio.
The reaction ratio of aluminum trichloride decreased with increase in its supply and decrease in temperature, but it increased when the reaction zone was extended.
The deposited aluminum contained small amounts of silicon and iron, in which the content of silicon was larger than that of iron. The purity of aluminum was higher than 99.6%. Furthermore, the extracted aluminum was melted and made into a thin plate by rolling.