Extraction of aluminum from high iron bauxite by carbothermal reduction-ammonium sulfate roasting

摘要

A new preparation of alumina from high iron bauxite, which has not been being made reasonably use of yet, has been studied. Iron in high iron bauxite was removed by carbothermal reduction and aluminum-rich slag could be obtained. Then aluminum was extracted from aluminum-rich slag by ammonium sulfate roasting. After leaching, Al_2(SO_4)_3 was obtained, which can be used for preparation of alumina. The effects of roasting temperature, roasting time, ammonium sulfate/aluminum-rich slag mass ratio were investigated. Optimum roasting conditions from aluminum-rich slag by ammonium sulfate were found as roasting temperature: 400°C; roasting time: 120min; ammonium sulfate/aluminum-rich slag mass ratio: 6. Approximately 98% of aluminum was effectively extracted.