The effect of pre-roasting on nickel extraction from limonite ore by acid leaching method

In this study, the effect of pre-roasting on leaching of limonitic laterite ore, obtained from Sorowako, South Sulawesi, Indonesia was investigated. The products were characterized by X-Ray Diffraction (XRD), X-ray Fluorescence (XRF), and Atomic Absorption Spectroscopy (AAS). The phase transformation of limonite minerals roasted was investigated by X-Ray Diffraction (XRD). The roasting experiment results show that there is a phase transformation process of dehydroxylation of goethite at roasting temperatures of 600°C. Pre-roasting of the limonite alters its mineralogical composition, thus making it more amenable to leaching. The leaching result of ores roasted contains higher Ni (4.80%) than raw ore (4.17%). The roasting temperature of 600°C appears to provide the maximum nickel recovery of 93.48%. In addition, the maximum nickel recovery is affected by the concentration of H2SO4. This process is one of the technical and economic developments of nickel extraction methods.