Microwave-drying process and mineral phase analysis of low-grade complex laterite ores

Silicon carbide as a assistant wave-absorbing material was used to study the microwave-drying process of a low-grade laterite ore.The effects of SiC mass fraction on the weight-loss rate and phase composition of the laterite ore were analyzed by thermogravimetric analysis (DTG),X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FT-IR).It is shown that when the SiC-to-ore mass ratio is 2.2:1,most of surface-absorbed water and part of crystal water in the laterite ore can be rapidly removed by microwave drying for 30 min.Overheating phenomena can be avoided by controlling the addition amount of SiC,too.Microwave treatment changes the microstructure and promotes the decomposition of the laterite ore.Hydrogen reduction experiment results indicate that the microwave-drying process benefits to the reduction of nickel and iron oxides in the laterite ore.The reduction rates of iron and nickel in samples through microwave drying are higher than those through conventional drying.