Influence mechanism of different types of coal on selective nickle reduction in nickel laterite reduction roasting

With a nickel laterite of 1.86% Ni and 13.24% Fe as a sample,the influence of different types of coal on selective nickel reduction in nickel laterite reduction roasting was studied with stone coal or anthracite as a reductant.It is indicated that nickel can be selectively reduced with stone coal as a reductant.The results obtained by X-ray diffraction(XRD) and scanning electron microscopy(SEM) show that taenite is the main form of nickel and iron in the roasted products when the dosage of coal is small,but the main mineral form changes into kamacite with the dosage of coal increasing.At the same time,with the dosage of coal increasing,the proportion of nickel decreases and the proportion of iron increases in Ni-Fe containing minerals produced after roasting.The roasted products are formed as taenite with stone coal as a reductant,the amount of gained Fe is lower but the selectivity for nickel is stronger than that with anthracite as a reductant,so Ni-Fe concentrate ores with high grade of nickel are obtained.