Effects of roasting pretreatment in intense magnetic field on digestion performance of high iron bauxite

Abstract

This paper investigates the changes of phase and apparent morphology under the combined effects of an intense magnetic field and temperature field. The effect of different roasting conditions on the digestion and settling performance of high-iron diaspore is also studied here. The results indicated that roasting pretreatment under high magnetic fields can change the microstructure of bauxite, hence improving its digestion properties. The optimum roasting conditions in intense magnetic field for high-iron bauxite are: the roasting temperature is 500°C, roasting time is 60min and the magnetic field intensity is 9T. The digestion rate of alumina for roasted ore is 71.82% when digested at 210°C for 60min with the digesting liquor ratio of 1.69, which is ~20% higher than that of raw ore. The settling performance of the digested slurry is also improved significantly when using roasted bauxite treated in intense magnetic field.