Melt purification principle

Fused alumina is also known as fused alumina. It is made from calcined alumina or alum as raw material, fused by electric arc furnace in reducing atmosphere, separated from metal and other impurities, and then condensed. The main raw material of molten alumina is calcined alumina or alum. When calcined alumina is used as raw material, chemical reaction will not occur in the arc due to the low impurity content, only the melting of AI2O3 and α- The crystallization and growth process of Al2O3. However, it is not the case when natural alum is used as raw material. In addition to AI2O3, alum also contains impurities such as SiO2, TiO2, Fe2O3, CaO, MgO and K2O. The process of producing rigid length from fused alum is to reduce other oxides other than AI2O3 to metal residues and separate them, which is a melting contact purification process.