Drying Kinetics of a Philippine Nickel Laterite Ore by Microwave Heating

The microwave drying of a Philippine nickel laterite ore was proposed as an alternative drying method to reduce the air pollution before further pyrometallurgical processing. The effect of thickness of ore bed and microwave power on the specific energy consumption and effective diffusivity were assessed. The results show that the specific energy consumption decreases with increasing the bed thickness and that the specific energy consumption exhibits a minimum at 1200 W. Besides, the increase of nickel laterite thickness and microwave power promotes the effective diffusivity. Compared with the removal of free water, crystalline water removal is proved to be much more energy-intensive. Furthermore, the specific energy consumption in microwave drying of laboratory scale is substantially higher than commercial rotary kiln drying.