Recovery of alumina and ferric oxide from Bayer red mud rich in
iron by reduction sintering
(School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
Abstract: A great amount of red mud generated from alumina production by Bayer process not only threatens the environment but also causes waste of secondary resources. High-iron-content red mud from Bayer process was employed to recover alumina and ferric oxide by the process of reduction-sintering, leaching and then magnetic beneficiation. Results of thermodynamic analyses show that ferric oxide should be reduced to Fe if reduction of ferric oxide and formation of sodium aluminate and calcium silicate happen simultaneously. Experimental results indicate that alumina recovery of Bayer red mud can reach 89.71%, and Fe recovery rate and the grade of magnetite concentrate are 60.67% and 61.78%, respectively, under the optimized sintering conditions.
Key words: high iron content; red mud; recovery; reduction; sintering; magnetic beneficiation