Extraction of ZnO and SiO_2 from digestion liquor of high silica zinc oxide ore roasted with alkali by stepwise carbonation and acid leaching processes

摘要

The digested liquor of high-silicon zinc oxide ores, which is processed by alkali roasting method, is a mixed solution of NaOH, Na_2ZnO_2, Na_2PbO_3 and Na_2SiO_3. The liquor can be separated by stepwise carbonation, ZnO and SiO_2 can be prepared by acid leaching. The product of the first step of carbonation is Fe_2O_2, which can be used as Iron concentrate. In the second step, ZnO, SiO_2 and PbO are precipitates out, we can get ZnO with further sulfuric acid leaching, and get SiO_2 by chlorhydric acid leaching from the filter residue. There will be only Na_2CO_3 left in the liquor, which can be recycled after causticization processed by CaO.