Carbon dioxide utilization in mineral processing

Abstract

Mining and mineral processing, significant contributors to CO₂ emissions, can reduce their carbon footprint and support a circular economy by integrating CO₂ into various unit operations, offering a promising way to mitigate emissions while enhancing mineral recovery and waste management. This review examines CO₂ utilization in leaching, flotation, wastewater treatment, and CO₂ sequestration via mineral carbonation using tailings. Emerging CO₂-augmented leaching techniques, including CO₂-water, supercritical CO₂, CO₂-ammonia, ionic-liquid, and CO₂-cyanide leaching have shown improved performance for a limited number of minerals at the laboratory scale. Similar to its role in leaching, CO₂ can act as a depressant or pH modifier in flotation, improving process selectivity and efficiency while reducing the need for additional chemicals. For water treatment, CO₂ facilitates the precipitation of heavy metals and contaminants under optimal conditions. CO₂ sequestration through mineral carbonation provides a sustainable method for locking CO₂ in stable mineral forms, utilizing tailings for both waste management and carbon capture. CO₂ utilization in flotation, leaching, and water treatment is currently limited to lab-scale experiments, emphasizing the need for scale-up trials to fully assess technical feasibility and identify potential bottlenecks associated with large-scale implementation. This review also identifies key challenges, including process optimization, scalability, and the need for further technological advancements. Future research should address these barriers to enable the practical integration of CO₂ utilization into mineral processing operations.