Waste materials for carbon capture and storage by mineralisation (CCSM) – A UK perspective

This work reviews the advantages and disadvantages of using mineral wastes for CCS and their potential in CO2 abatement, highlighting the potential applications and scenarios. This study indicates that a variety of inorganic waste materials such as pulverised fuel ash, municipal solid waste ash, cement kiln dust, biomass and paper sludge ash and sewage sludge ash are available feedstocks for Carbon Capture and Storage by Mineralisation (CCSM) in the UK. The high variability of both the waste amounts and chemical composition represent a major obstacle to the deployment of these materials in CCSM. Currently, mineral waste resources for mineral carbonation have the theoretical potential to capture about 1 Mt/year CO2 in the UK, considering only the materials not recycled that are currently sent to landfill. Moreover, inorganic waste as a CCSM resource is in many ways more complex than the use of natural minerals due to uncertainty on future availability and high chemical variability and might be viable only in niche applications. For example, the use of inorganic wastes (concrete waste and steel slag) and buffer solutions in spray trickle bed systems (able to sequester 50% of the CO2 entering the system) was estimated to have costs competitive with geological storage.