Effect of pretreatments to improve nickel leaching from laterites in carboxylic media: Mechanism and kinetic model

Abstract

In recent years and with the rapid development of electric vehicles and batteries, the demand for nickel as an important material in clean energy technologies has increased. Extensive research efforts have been devoted to develop a clean alternative technology capable of obtaining this metal from low-grade laterite. This study investigated the laterite leaching using sodium citrate as an alternative reagent to conventional inorganic acids; the effect of pyro- and hydrometallurgical pretreatments on ore morphology and structure was evaluated. The results showed that although citrate tends to be selective for nickel, its dissolution is associated to the iron. The decreasing core model (SCM) was used to determine the best fit for the experimental data. Using the Arrhenius expression, the apparent activation energy for the nickel and iron solutions was estimated, verifying a chemical reaction control in the process.

Keywords

• Nickel-extraction
• Pretreatments
• Laterite
• Leaching
• Sodium-citrate
• Kinetics