Upgrading Titaniferous Metallurgical Slag by Activation-Acid Leaching Process

摘要

Large reserve of vanadium-titanium magnetite ore has been found in China. Currently, ilmenite concentrate with 47%TiO_2 has been obtained from the ore by beneficiation. By electrical furnace smelting, a titanium-rich slag with about 73% TiO_2 is made from the concentrate, which is still not suitable for the production of titanium white by chloride process due to its high content of impurities, such as CaO, MgO, etc. This work has developed a new process to upgrade the slag. The slag is first activated by roasting at a temperature of 700°C to 900°C with addition of alkali metal salts. The activated slag is then leached by sulphuric acid and the leached slag is calcined at a temperature of 900°C. By this process, the Ti-rich product with 92% TiO_2, 0.45% MgO and 0.29% CaO is obtained. The mechanism of activation-acid leaching is studied by XRD and thermodynamic investigation.