Mineralogical characterization of South African mine tailings with aim of evaluating their potential for the purposes of Mineral Carbonation

South Africa is an energy intensive economy which primarily relies on the burning of fossil fuel such as coal. The South African coal energy sector accounts for approximately 420 million metric tonnes of carbon dioxide emitted per annum. With present alarming concerns with regards to the ever-increasing atmospheric carbon dioxide concentrations resulting in global warming and climate change, several mitigation strategies have to be implemented. A majority of Carbon Capture and Storage (CCS) technologies require monitoring from potential leakages, making the process expensive. However, a benign technology exists to permanently store away anthropogenic CO2 with products obtained instantaneously. This CCS technology is known as Mineral Carbonation. The fundamental procedure is a reaction between (magnesium - calcium - iron) silicates and CO2 to form carbonates. The products of from the reaction require no monitoring and the fear of leakage of CO2 is eliminated. Moreover, the carbonates from this technology are useful in the road, agriculture and building industries. The CO2 storage capacity in mineral carbonation exceeds other CCS techniques. The South African mineral industry annually produce immense tonnages of ultramafic mine tailings. Due to the generally fine nature of the tailings, no further cost would be incurred in grinding the material. The platinum group metal (PGM), nickel and copper companies are examples of industries that produce massive tonnages of which could serve as potential feedstock for the purposes of mineral carbonation. Recent studies have shown that, the potential feedstock could sequester close of 70% of the annual CO2 produced at Secunda, South Africa.