Chloridization and Reduction Roasting of High-Magnesium Low-Nickel Oxide Ore Followed by Magnetic Separation to Enrich Ferronickel Concentrate

The chloridization and reduction roasting of high-magnesium, low-nickel oxide ore containing 0.82 pct Ni and 31.49 pct MgO were investigated in this study. Mineralogical investigation indicated that 84.6 pct of nickel was associated with silicates, and nickel was well distributed in mineral in the form of isomorphism. A series of chloridization tests with different added proportions of sodium chloride and coal along with different roasting temperatures and times was conducted. The results indicate that for a ferronickel content of 7.09 pct Ni, a nickel recovery of 98.31 pct could be obtained by chloridizing the laterite ore at 1473 K (1200 A degrees C) for 20 minutes with the addition of 10 wt pct sodium chloride and 8 wt pct coal followed by the application of a 150-mT magnetic field. X-ray diffraction indicated that the nickel is mainly present in the form of ferronickel, which can also be detected by SEM-EDS. Compared with the roasted ore with no added chlorinating agent, the ore roasted in the presence of sodium chloride exhibited enhanced ferronickel particle growth.