Nickel laterite processing a critical review of current ad 2027 Minerals En

Nickel laterite processing is commonly reviewed route by route, although ore mineralogy, thermal preparation, sulfur transfer, reduction selectivity, metal-carrier choice, and downstream refining are physically coupled. This critical review treats the thermal front end as one interface in an ore-to-product chain. A reproducible OpenAlex update search performed on 01 October 2026 retrieved 148 unique records; 59 advanced from title-and-abstract screening to manual assessment, supplemented by citation chaining and verified DOI metadata. Evidence is graded from concept or model to controlled laboratory, pilot or plant-adjacent, and industrial operating data. The synthesis separates limonitic and saprolitic front ends and places the legacy Caron route between reduction roasting and aqueous refining. It shows that low-carbon claims are controlled by ore grade, moisture, product basis, electricity and hydrogen source, allocation, and refining depth. In mixed-energy modeling, ferronickel and nickel pig iron required 309 and 598 GJ per tonne of contained Ni and emitted 18 and 69 t CO2-eq per tonne of Ni, respectively; these values are boundary-specific rather than universal rankings. A 2025 hydrogen-plasma study produced Ni-enriched ferronickel in 10-g batch tests and projected up to 18% energy savings and 84% lower direct CO2 emissions under renewable-electricity and green-hydrogen assumptions, but continuous operation has not been demonstrated. Kiln sulfur transfer and inhibition remain controlled laboratory evidence and govern operability, emissions, and product sulfur rather than direct decarbonization. Product claims must distinguish mixed hydroxide or sulfide precipitate, ferronickel, nickel pig iron, matte, and battery-grade salts because each carries different impurity and refining burdens. The resulting framework links mineralogy, front-end state, metal carrier, refining duty, residue closure, carbon boundary, and evidence maturity to define testable priorities for lower-carbon nickel supply.