Research On New Comprehensive Utilization Method For Red Mud From Bayer Process

Comprehensive utilization of red mud is a worldwide problem. Followed by the development for pollution control, this problem has been caused more and more attention,and becomed a issue that restirct sustainabel development of alumina industry. So how to comprehensily utilize red mud is of theoretical and practical significance.In this paper, physical and chemical properties of Bayer Red Mud is analysised at first. Then Red Mud is mixed with reductant and sintering additives to form a multi-component mixture and sintered at high-temperature. Liquid/solid ratio and other parameters are controlled for Alkali dissolution. Sodium aluminate solution and the iron-rich residue can be obtained. Sodium aluminate solution is delivered to aluminaoxide process and Iron-rich residue for magnetic seperation with controlled magnetic field intensity and other parameters. High-grade DRI can be got from magnetic seperation. Otherwhise, Non-magnetic residue is used for building materials. The factors and parameters that effect iron reduction and Sodium aluminate dissolution are studied. Industrial reduction sintering test with rotary kiln and sintering process,as well as material ratio are studied.Under laboratory conditions, DRI is extracted from Bayer Red Mud by coal-based reduction. High-quality sponge iron with metallization rate of 92.9%, an iron content of 93.7% can be obtained. Iron recovery rate of 94.42% can be reached. aluminoxide dissolving rate of 75%, and sodium oxide dissolving rate of 85% can be reached in respective steps. The results idicated that new process for Bayer Red Mud treatment is feasible. Not only the valuable metal can be recoveried, but also the red mud output can be reduced. In industrial test, metallization rate of 50%-70%, recovery rate of 30% aluminoxide dissolving rate of 75%, and sodium oxide dissolving rate of 50% be reached. They are obviously lower than that from laboratory test. A lot of work should be done to improve the industrial process. Based on analisis, some suggestions are given for further industiral research...