CO2 Sequestration by Mineral Carbonation in the Australian Context

This paper focuses on the sequestration of CO{2} through mineral carbonation, i.e. reaction with magnesium silicate minerals such as serpentine to form mineral carbonates. It highlights the potential advantages of this route over alternative sequestration approaches and describes research aimed at demonstrating an economically viable mineral carbonation industry for Australia. Mineral carbonation presents a compelling case since it is permanent, safe, readily auditable and thermodynamically favoured. It also offers sufficient capacity to sequester all global anthropogenic emissions for many decades. The Albany Research Center (ARC) in the USA has previously demonstrated technically feasible routes for mineral carbonation based on high pressure aqueous systems. The economic viability of these processes has not yet been established for CO{2} prices anticipated in the medium term. Improvements in reaction rates and conversions are required, as well as optimisation of energy utilisation via process integration. These aspects are being addressed in current research programs. Here, we consider the development of a process for direct gas-fired thermal activation of serpentinite ore followed by supercritical carbonation using the ARC process. Opportunities for process optimisation, including winning of iron ore and energy integration are identified. The potential for a new Australian mining industry for mineral carbonation is outlined. Suitable outcropping resources exist in both NSW and Queensland, in close proximity to coalfields and power generation. While the scale of operations required is large, it is comparable to that of current mining operations. It is concluded that this mining-based approach offers many potential advantages over alternative sequestration approaches and could assist in meeting the biggest challenge yet faced by the industry, and indeed by the world.