Aluminum-iron separation in high-acid leaching solution and high-purity alumina preparation

The demand for bauxite has increased sharply due to the fast development of alumina industry, so new technology must be developed to take full advantage of nontraditional bauxite resources to realize a continuous supply of bauxite. In this experiment, anatase sulfuric acid leaching liquor is taken as the research object to conduct aluminum-iron separation and high-purity alumina preparation. The leaching solution contains 34.20 g/L of Al2O3, 25.30 g/L of TFe, 7.96 g/L of TiO2, 12.74 mg/L of Sc2O3, and 288.72 g/L of H2SO4. When the temperature is low, aluminum and iron condensation, which are not conducive to the separation and recovery of various elements, may occur easily. In this study, the ammonium aluminum sulfate crystallization-recrystallization and ion exchange-calcination method is adopted to effectively separate aluminum and iron in a strong acid solution comprising high concentrations of aluminum and iron without consuming high residual acid in the leaching liquor. Consequently, successful production of high-added-value product 4N (99.99%) level gamma-Al2O3 with ammonium aluminum sulfate is obtained through separation as the raw material. The product has a specific surface area of 7.845 m(2)/g with a nearly spherical shape and being evenly distributed. Therefore, it realizes high-value aluminum utilization from nontraditional bauxite.