Study On Composition And Dealkalization Method Of Red Mud In Lime-sintering Process

Red mud is a kind of solid waste by product raised from the alumina refining plant. It is reported that at least more than 3,000,000 ton red mud is discharged annually in China .The red mud accumulated amount discarded of China has reached 6.6～8.5% of all over the world.Among those only little part was reutilized in some different ways, the rate of reutilization being said to be fewer than 15%, and large amount of red mud was exposured to atmosphere, which not only occupy land and caused pollution on environment but also resulted in the waste of natural resource. Therefore how to eliminate the problem of pollution and at the same time to transfer the waste residue into useful raw material became a social focus meanwhile an interesting research subject for many investigators.The object of this paper is red mud in lime-sintering process from aluminum industry. The main chemical composition were determined by various ordinary chemical analyses. The Chemical Composition of this kind of red mud was determined,includ of CaO,SiO₂,Al₂O₃,Fe₂O₃ etc. Some R₂O (Na⁺ + K⁺) were finded in this kind of red mud which content is about 4%.At the same time, this paper studied the physical phase of lime-sintering red mud by IR, X-ray diffraction and DSC. Results of TG-DTA, XRD, and IR analysis showed that the most important constituent of the red mud is CaCO₃ and (?)-C₂S. Moreover, If the total content of R₂O can be reduced to less than 1%, lime-sintering red mud would be a good raw material.At first,I studied dealkalization method by single factor test.I further study it b Orehogonal design on the base of the single factor method.On the basis of studied chemical and physicochemical properties of red mud, a effective dealkalization method was established and optimized.