EXTRACTION OF ALUMINA FROM BAUXITE

摘要

In the production of alumina by the Bayer process from bauxite containing gibbsite and boehmite and having an iron content below 5% (calculated as Fe2O3) the extraction of boehmite in the digestion stage (which is carried out at 225-270.degree.C) is improved by incorporating an iron-containing mineral, in which iron oxide is present in very fine particle size, in sufficient quantity to raise the Fe2O3/ TiO2 ratio to at least 1.3. The iron-containing mineral may be a high-iron bauxite.