Effects of intense magnetic field on digestion and settling performances of bauxite

Lü Guo-zhi(吕国志)^{1, 2}, ZHANG Ting-an(张廷安)^{1, 2}, WANG Xiao-xiao(王小晓)^{1, 2}, ZHANG Xu-hua(张旭华)^{1, 2}, LIU Yan(刘燕)^{1, 2}, ZHAO Qiu-yue(赵秋月)^{1, 2}, DOU Zhi-he(豆志河)^{1, 2}

(1. Key Laboratory of Ecological Utilization of Multi-metal Intergrown Ore of Ministry of Education
(Northeastern University), Shenyang 110004, China;
2. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China)

Abstract:The effects of magnetic field intensity, roasting temperature and roasting time on digestion rate and settling performance of bauxite with different iron contents were investigated systematically. The results indicate that such magnetic treatment can profoundly change the microstructure and digestion performance of bauxite. For the two samples carrying different iron contents, phase transformation of the aluminum oxide phase proceeds faster in the high iron bauxite than the low one. The optimal pretreatment conditions of low iron bauxite are roasting temperature 550 °C and magnetic field intensity 6 T, while for high iron bauxite are 500 °C and 9 T. The digestion rate of alumina can reach 95% and 92% at digestion temperature of 190 °C and 250 °C. The settling performances of roasted ore by intense magnetic field after digestion are enhanced through pretreatment.

Key words:bauxite; intense magnetic field; phase transformation; digestion performance; settling performance