Effect of reduction temperature and sodium-based additives on nickel upgrading process of laterites ores

In this present work, the selective reduction of nickel laterite was conducted by using 10 wt. % of sodium carbonate, sodium chloride and sodium sulphate as additives. The 5 wt. % of palm shell charcoal was used as the reductant. The selective reduction process for nickel laterite was carried out from 950ºC to 1150ºC for 60 minutes followed by wet magnetic separation using 500 Gausses permanent magnet. The characterization of reduced ore was performed by X-Ray Diffraction, optical microscope and Scanning Electron Microscope with Energy Dispersive X-Ray Spectroscopy, while the chemical composition of concentrate or ferronickel was identified by X-Ray Fluorescence. The results showed that the nickel grade was increased with the increasing of reduction temperature for nickel ore with sodium sulfate additive. Nevertheless, it was relatively constant for sodium carbonate and sodium chloride additive. Nickel recoveries found increased with the increasing of reduction temperatures of nickel ore with sodium-based additives. The ferronickel particle was agglomerated and growth with the increasing of reduction temperature, thus it provided favourable conditions for the separation of ferronickel from impurities in the magnetic separation process.