Nickel leaching from low-grade nickel matte using aqueous ferric chloride solution

Nickel leaching from low-grade nickel matte (LGNM) using aqueous ferric chloride solution was studied. The influence of factors such as leaching temperature and concentration of ferric chloride on the nickel leaching ratio was investigated. The results show that increasing leaching temperature and concentration of ferric chloride increases the nickel leaching ratio. The overall nickel leaching process follows the unreacted shrinking core model, and the surface chemical reaction is the rate-controlling step. The activation energy and the reaction order of the nickel leaching process, controlled by the surface chemical reaction, were calculated to be 52.96 kJ·mol −1 and 0.5, respectively. Therefore, the kinetics equation for the nickel leaching was found to be 1 − (1 − α ) 1/3 = 7.18 × 10 4 C 0.5 exp[− 52,960/( RT )] t .