Atmospheric acid leaching of powdery Ni-Co-Fe alloy derived from reductive roasting of limonitic laterite ore and recovery of battery grade iron phosphate

The efficient and inexpensive extraction of Ni and Co from limonitic laterite ore is becoming imperative due to the rapidly growing demand for nickel and cobalt driven by electric vehicles (EVs). In this work, powdery Ni-Co-Fe alloy was prepared from limonitic laterite via reductive roasting followed by magnetic separation, with nickel and cobalt recoveries of 91.9% and 93.3%, respectively. Most of the gangue material was rejected, and the obtained powdery alloy was readily dissolvable in sulfuric acid solution at atmospheric pressure. Under the conditions of 2.5 M H2SO4, 80 °C, 60 min, L/S ratio of 8 mL/g, the extractions of Ni, Co and Fe were 98.5%, 99.9% and 95.6%, respectively, and chemical reaction was the rate-controlling step. The proposed process is promising for the utilization of limonitic laterite ore with high leaching efficiency and less leach residue discharge.