A novel hydrometallurgical approach to recover valuable metals from laterite ore

• Atmospheric acid leaching of laterite blends was investigated.
• Al and Cr can be separated from Fe, Ni, Co and Mn by adjusting the pH value of the solution.
• Metal co-doped magnesium ferrite was synthesized from the acid leaching solution.
• The overall metal recovery for prepared ferrite could be about 90%.
• A novel approach for comprehensive utilization of laterite blends was proposed.

A novel hydrometallurgical process was developed to produce metal co-doped magnesium ferrites from saprolite and limonite laterite blends by using an atmospheric acid leaching–coprecipitation method. The effects of initial acid concentration, liquid to solid ratio and leaching time on the metal leaching efficiencies were investigated systematically. It is shown that extraction efficiencies of Fe, Ni, Mn, Co and Mg can reach 94.6%, 96.9%, 86.0%, 84.8% and 72.6%, respectively, after leaching for 60 min at 100 °C with the liquid (2.75 mol·L− 1 HCl acid) to solid (saprolite and limonite laterite blends) ratio of 10:1 mL·g− 1, and saprolite to limonite mass ratio (Msaprolite/limonite) of 5:5. Under the optimum leaching conditions, the influence of Msaprolite/limonite on the synthesis of metal co-doped magnesium ferrites from leaching solutions was also discussed. X-ray Diffraction (XRD) results showed that pure metal co-doped magnesium ferrites could be obtained when the Msaprolite/limonite was controlled at 7:3, with the initial acid concentration of 2.75 and 3.0 mol·L− 1, respectively.