Abstract: There are too much iron and alkaline in red mud, which hinders its utilization in cement. In order to enhance the reusing rate of red mud in cement material, this research paid adequate attention on reduction methods for iron recovery from red mud, water heated ion-exchanging methods using calcium carbide slags and oxalic methods for dealkalization of red mud, eventually used refactored red mud after iron recovery and dealkalization to prepare cement clinker. The results show that under the optimized condition that the sintering temperature is 1 400 ℃, lasting time is 1 h, rice husk ash adding content is 9.08% (mass fraction), cooling method is water cooling, the iron recovery rate of red mud is 77.24% while the content of iron declines to 9.39% (mass fraction) after iron recovery. Under the condition that reacting temperature is 90 ℃, deironed red mud and calcium carbide slags mass ratio is 1:1, liquid to solid rate (mL/g) is 6, reacting time is 7 h, the dealkalizaiton rate of ion exchanging methods using calcium carbide slags is 89.30%, meanwhile, the content of Na₂O in refactored red mud drops to 0.592% (mass fraction), which meets the requirement for cement ingredients that alkaline content must be lower than 1%. When the rate value of cement raw material, namely the lime saturation factor is 0.88, silicon rate factor is 2.4, aluminum rate factor is 1.4, cement raw materials prepared using refactored red mud possess good burnability under the sintering temperature ranging from 1 300 ℃ to 1 450 ℃. When the sintering temperature is 1 350 ℃, grains in cement clinkers show as irregular polygons with normal morphology. Accordingly, the optimum sintering temperature for cement clinker preparation adding refactored red mud is 1 350 ℃.

Key words: red mud, rice husk ash, reduction method for iron recovery, calcium carbide slag, dealkalization rate, cement clinker