Production of ferronickel from limonitic laterite ore using hydrogen reduction and cementation

Production of ferronickel from limonitic laterite ore using hydrogen reduction and cementation was studied by relying on a novel hydrometallurgical process consisting of the key steps: calcination, reductive roasting with hydrogen gas, 2-stage atmospheric hydrochloric acid leaching, and cementation with Fe. The introduction of the reusability of H₂-reduced limonitic laterite as a cementation agent instead of conventional Fe sources is an important approach of the proposed process in terms of enhancing cost-effectiveness. The effects of the type of Fe source, the amount of cementation agent, and the temperature on Ni cementation were experimentally determined. The kinetic analysis confirms that Ni cementation behavior can be elucidated by applying 1st order reaction kinetic principles, and the temperature is the most effective parameter. Based on the linear relationship of empirical data with the 1st order kinetic model and by the calculations associated with Arrhenius law, the value of the activation energy of Ni cementation onto Fe could be deduced as 7.5 kJ/mol. Greater than 99% of Ni could be recovered under the most suitable conditions, and the final product was obtained as ferronickel cement (Ni 10%), which can be applied in steel smelter as a prominent intermediate.