Characterization of fluidized reduction roasting of nickel laterite ore under CO/CO2 atmosphere

Fluidized reduction roasting is an efficient metallurgical technique. However, its application to nickel laterite ore has rarely been reported. In this paper, the effects of reduction temperature, reduction time, CO concentration, and material particle size on the roasting characteristics of ferronickel fluidization reduction were investigated. Combined with X-ray diffraction, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) characterization, the mineral phases and microscopic morphology of nickel laterite ore and its roasted ores were analyzed in depth. The results indicated that under the condition of a CO/CO2 ratio of 1:1, a reduction temperature of 800 degrees C, and a reduction roasting time of 60 min, a nickel-iron concentrate with a nickel grade of 2.10% and an iron content of 45.96% was produced from a raw material with a nickel grade of 1.45%, achieving a remarkable nickel recovery rate of 46.26%. XRD and SEM-EDS analysis indicated that nickel in the concentrate mainly exists in the form of [Fe, Ni], while the unrecovered nickel in the tailings is primarily present in the form of [Fe, Ni] and Ni2SiO4 in forsterite. This study established a theoretical foundation for further exploration of fluidized reduction roasting technology.