Technical feasibility, technoeconomic, and life cycle assessment of CO2 sequestration using domestic nickel mine tailings: A direct ex-situ hydrothermal approach

Document Type

Article

Publication Date

11-15-2025

Abstract

Direct ex-situ mineral carbonation offers a pathway for permanent CO2 sequestration through reactions with silicate minerals. While conventional mining and processing of feedstocks are energy-intensive and costly, the utilization of pre-ground mine tailings rich in CO2-reactive silicates may provide a more economical alternative. This study evaluates the technical feasibility, technoeconomic assessment (TEA), and life cycle assessment (LCA) of direct aqueous mineral carbonation using domestic nickel mine tailings. Experimental results demonstrated that 16–35 kg CO2 per ton of mine tailings could be sequestered at 125–185 °C without additional comminution. Further particle size reduction, or the use of the slime fraction, increased CO2 uptake to 46–91 kg CO2 per ton. Mineralogical characterization confirmed the carbonation of olivine and a fraction of pyroxene to form siderite and magnesite, while plagioclase and quartz remained largely inert. The TEA/LCA analysis revealed a sequestering cost of > $585 per ton CO2, with a net global warming potential (GWP) of at least 1.3 CO2-equivalent. Scenario modeling indicated that achieving cost and environmental targets ($100 per ton CO2 and GWP <1) would require ultrafine tailings with ≥80 % olivine content and the use of low-carbon heat source. This study represents the first integrated evaluation of both the technical feasibility and technoeconomic scenarios of CO2 sequestration using direct ex-situ carbonation route for nickel mine tailings.

Publication Title

Journal of Cleaner Production

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