Bayer Process Red Mud Selected Iron New Technology

The second alumina plant of Shandong Alumina Co. LTD produces alumina by Bayer low-temperature digestion using trihydrate bauxite imported from Indonesia. This combination process whose nature is big sintering and little Bayer is formed by adding the alumina plant of Shandong Alumina co. LTD. The red mud of Bayer process is recycled in sintering process. The main compositions of red mud of the second alumina plant of Shandong Alumina Co. LTD are: alumina 15%~25% iron oxide 25%~35% silicon oxide 15% - 25% sodium oxide 5% - 15%, some magnesium oxide and calcium oxide ,So much iron oxide in the red mud leads to the limitation of precipitation tank of Bayer process and adds the burden of sintering process. All these limits the producing ability of Bayer process.In order to improve the ability of precipitation tank and decrease the burden of sintering batching and recycle the iron mineral, the new ore dressing of red mud is invented by our effort. The main project is: firstly, the discrimination between red mud and ore sand;the separated ore sand will be separated and washed for two times, then red mud sand whose iron percentage(iron percentage is various according to ore grade) is about 30%—40% will be made. Secondly, grinding. The valued ores will be separated from other ores and this will make concentration possible;thirdly, to discriminate iron ore and tailing sand. Then, concentrating ore will be separated and iron ore is made.To explore selection of red mud, Flotation, gravity dressing, sintering magnetic dressing, pulsating high-grade magnetic dressing are experienced. We believe classifying of iron ore in red mud by pulsating high-grade magnetic dressing is reasonable according to the experiments. Grade of selected iron ore concentrate is about 56%, recycling rate is about 90%. At the same time, flowsheet is simple and easy to control. This method can be used to make full use of resource, recycle the waste material and unify the environmental benefit, economical benefit and social benefit.