Abstract:Experiments on desilication of certain bauxite under coal by roasting, desilication by alkali leaching, and Bayer digestion were carried out. The results show that CT and ST in the roasted ore can drop to 0.03% below and 0.20% below respectively after roasted for 10 minutes at 970—1 020 ℃. The A/S of the desilicated concentrate can rise to 10.02—11.25 after the roasted ore desilicated by alkali leaching, and the recovery ratio of alumina during desilication is over 98%. The digestion efficiency of alumina is 83.94%—85.04%, and relative digestion efficiency of alumina is 92.13%—94.46% under the conditions including digestion temperature of 265 ℃, Na2OK=236 g/L, lime addition of 12%, αK of about 1.45, and digestion time of 60 min. Na2O in red mud is 1% below, which good basic conditions have been created for safe storage and comprehensive utilization of red mud.