Mineral carbonation of ultramafic tailings: A review of reaction mechanisms and kinetics, industry case studies, and modelling

Abstract

Reduction of greenhouse gas emissions is becoming a greater priority in the mining industry due to increasing social pressures, government incentives, and its consideration in companies stock evaluation. Carbon capture and sequestration in ultramafic tailings (mineral carbonation) is one technology companies can use to offset their carbon emissions. Mineral carbonation refers to the spontaneous reaction of carbon dioxide with divalent metal minerals, which safely and permanently stores carbon dioxide as a carbonate sediment. Carbon sequestration can occur passively in ultramafic mine tailings storage facilities or under optimized conditions in process designs. This review discusses the literature on mineral carbonation reaction mechanisms, candidate minerals, kinetic parameters, potential methods to accelerate mineral carbonation, examples of industry mineral carbonation, and mine-scale mineral carbonation modelling. • Mineral carbonation reaction rate limiting mechanisms and thermoynamics. • Effect of water saturation, temperature, mineralogy, depth, pH, CO 2 and grain size. • Technologies to improve CO 2 sequestration in ultramafic tailings. • Reactive transport modelling of mineral carbonation in ultramafic tailings.