Leaching of Alumina From High Ferrous Bauxite

The leaching of alumina from a high ferrous bauxite in Yunnan was investigated.The effects of several factors on leaching of alumina were examined.The results show that the optimal conditions for leaching of alumina are leaching temperature of 280℃,leaching time of 45 min,lime usage of 8%,caustic concentration of 225g/L.The relative leaching rate and the actual leaching rate of alumina are84.35% and about 75.94%,respectively.The results of energy spectrum analysis for the ore sample and XRD analysis for red mud show that hematite may be package a part of alumina then lead to reduce leaching rate of alumina.