An integrated process of CO2 mineralization and selective nickel and cobalt recovery from olivine and laterites

Abstract

Laterites are important nickel and cobalt natural resources. However, the current production technologies are challenged by limited application to different laterites ore types and large carbon footprints. The clean energy transition requires enhanced production of nickel and cobalt for battery manufacture with significant progress toward carbon neutrality. This work presents an integrated process of CO2 mineralization and simultaneously selective nickel and cobalt recovery from various feed materials including saprolite and limonite laterites and olivine. Carbon dioxide gas is reacted with magnesium and iron in the laterite of feed materials to form stable mineral carbonates for permanent CO2 storage. Simultaneously, nickel and cobalt are selectively leached into aqueous solution by using a complex ligand nitrilotriacetic sodium (NTA) and then recovered by sulfide precipitation as nickel sulfide concentrates. In the integrated process, the chemical consumption is limited to CO2 for carbon storage and hydrogen sulfide for precipitation of nickel and cobalt. Preliminary economic analysis and carbon neutrality calculations have been performed and confirm the feasibility for laterite processing. Each one tonne of laterite studied in this work can contribute to production of 10.1 ∼ 19.6 kg nickel and 0.33 ∼ 0.54 kg cobalt with nearly 90 % recovery and earn net benefits at $254 ∼ 547 with net carbon neutrality at 15 ∼ 63 kg CO2 sequestered as stable mineral carbonates. The novel process is favourable in technical feasibility, economics, and carbon neutrality and thus can make a significant contribution to the clean energy transition, CO2 storage and utilization, enhanced supply of critical metals, and comprehensive utilization of mineral resources.