Net negative carbon dioxide nickel mining examined through prospective technoeconomic assessment

Abstract Carbon dioxide removal (CDR) must scale rapidly to meet climate targets, yet durable pathways remain limited in cost and scalability. Nickel mine tailings provide a globally abundant resource for reaction with atmospheric carbon dioxide and the recovery of critical metals. Here we show that long-term CDR cost of an integrated acid-leach, bipolar membrane electrodialysis (BPMED), and aqueous carbonation system are ~ US$200 tCO₂⁻¹, enabling > 100 MtCO₂ yr⁻¹ of durable removal while shifting nickel production to net-negative emissions. We apply a prospective techno-economic assessment that combines cost reductions from technology learning with modelled changes in the background socio-technical context in which the process operates. However, $22 billion of cumulative investment is required to breakeven by 2045, the functional equivalent of an additional US$154 tCO₂⁻¹, but annual profits could be on the order of $5–20 billion in the latter half of the century. Sensitivity analysis identifies BPMED performance as key to feasibility which offers opportunities for technology innovation. These results establish tailings-based mineralization as a scalable CDR pathway that integrates mining into global climate mitigation strategies.