Abstract:An alumina refinery in Zunyi applies Bayer process to produce alumina with high sulfur bauxite as raw materials. Effect of rising of carbon and alkali in system on production is summarized. The causes of rise of carbon and alkali is studied and analyzed. The results show that siderite is the main carbonaceous mineral in bauxite, and amount of sulphate in mother liquor will significantly reduce amount of carbonate discharging from red mud during dissolution. In terms of production organization, control of use of high-carbon bauxite is changed to control of high-sulfur bauxite and high-carbon bauxite simultaneously. As a result, carbon alkali ratio of system is restored to normal level without salt discharging operation during evaporation process, and production cost is reduced.