Effect of Additives on Digestibility of Roasted Diasporic Bauxite during Roasting

The effect of additives on the digestibility of diasporic bauxite during its roasting is studied. The results show that addition of AlF_3 during roasting of diasporic bauxite can improve dramatically the extraction rate of aluminium. The extraction rate of aluminium in the roasted bauxite ore come up to 52% by adding 1% AlF_3 the bauxite, followed by roasting and digesting it at 185 ℃ for 1 hour. The extraction rate of aluminium obtained with AlF_3 is higher 15% than the one without AlF_3, and increasing AlF_3 the extraction rate of aluminium increases. When the content of AlF_3 added is up to 5%, the extraction rate of aluminium comes up to 71%; when 3% AlF_3 is added to the bauxite, the extraction rate of aluminium will reach 88% by roasting and digesting at 200 ℃ for 1 hour.