Comparative H2SO4 and H2SO4 + H2O2 leaching of a Turkish lateritic nickel ore

Comparative atmospheric H2SO4 and H2SO4 + H2O2 leaching experiments were performed using a Turkish lateritic nickel ore containing 1.52% Ni. The objective of this study was to analyze the dissolution behaviors of the ore under varying conditions. Key variables included acid concentration, temperature, and leaching time, with dissolution analyses for Ni, Fe, Co, and Mg. Results indicated that dissolution values in the H2SO4 leaching experiments increased to 60% (w/w) acid concentration at 95 °C, but higher concentrations resulted in decreased dissolution due to the formation of Fe2(SO4)3 compounds. Optimal conditions were identified at [H2SO4]= 45%, T=95 °C, t=45 min, yielding dissolution values of 99.12% for Mg, 95.58% for Ni, 92.63% for Fe, and 78.37% for Co. The activation energy for nickel dissolution was calculated at 30.57 kJ/mole, indicating that the dissolution process was predominantly controlled by external diffusion and chemical reactions. Furthermore, leaching tests with Caro's acid at 25 °C showed distinct behavior for cobalt, achieving 83.94% dissolution at low acid concentration, with significant increase in temperature during the reaction.