As carbon capture develops rapidly along several technology paths, sequestration research in Australia is focused on geo-sequestration. However, suitable options have yet to be identified for the Hunter Valley and Queensland coal and power generation hubs.

The sequestration of CO² through reaction with magnesium silicate minerals to form mineral carbonates presents a compelling case, since it is permanent, safe, readily auditable and thermodynamically favoured. This paper describes research aimed at demonstrating an economically viable mineral carbonation industry for Australia.

The Albany Research Center (ARC), 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 CO² 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 present process flowsheets 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, removal of waste silica 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 reasonable proximity to the coalfields. While the scale of operations required is large, it is comparable to that of current mining operations. It is proposed that this mining-based approach could assist in meeting the biggest challenge yet faced by the industry.