Study On The Resource Utilization Of Bayer Red Mud By Carbothermic Reduction

The red mud is the waste from the alumina process.Each year several million tons of discarded red mud not only takes up a lot of land,but also will cause some pollution on the environment if not handled properly.Much research has been done on the comprehensive utilization of red mud,but the technology that can make use of red mud on a large scale has not been discovered.According to the composition and phase of red mud in Bayer process,the carbon-bearing pellets of red mud had been investigated during the reduction and melting process.The slag system was modified and its desulfurization performance was evaluated.Based on these studies,a new process of using red mud resources was proposed.The research can provide a reference for the exploitage of red mud in iron and steel industry.The main conclusions were obtained as follows:(1)The carbon-bearing pellets of red mud were reduced at elevated temperatures.The metallization rate can reach over 83.5%,and the metallization rate increases with the increase of the reduction temperature.The metallization rate can reach 91.3%at 1200? in 12min,which is a satisfactory result.(2)Adding 24.9%?57.6%CaO and 9.4%?42.4%Al2O3 to the red mud metallization pellets,the separation of slag and iron can be realized at 1450?.The recovery rate of the metallic iron is above 92%and the quality of iron is in accordance with L04,which can be directly used as raw material for steel making.The total iron content in slag is less than 0.5%,The desulphurization rate can reach 76.6%by using the molten slag after upgraded.(3)The red mud from Bayer process can achieve its comprehensive utilization through a new technology,at the same time,the pig iron and refined desulphurization slag products are obtained.