Research progress on CO₂ mineralization of coal-based solid waste containing calcium and magnesium and its product performance

With the overconsumption of fossil carbon resources, resulting in a large amount of CO₂ and other greenhouse gas emissions, caused by global climate change has become one of the major challenges facing all mankind. At the same time, the development and utilization of coal resources will produce a large amount of coal-based solid wastes containing calcium and magnesium, such as fly ash, desulfurization gypsum and other solid wastes. How to realize efficient CO₂ capture and sequestration is a very challenging issue nowadays, as well as the large-scale comprehensive utilization of fly ash, coal gasification slag, and other large-scale heavy polluting industrial solid wastes is still in need of a breakthrough. Under the goal of “double carbon”, CO₂ mineralization from coal-based solid waste is a potential strategy to effectively address global warming, and mineral carbonation of coal-based solid wastes containing calcium and magnesium has great prospects for carbon dioxide capture and sequestration (CCS) as well as for the resource-based disposal of solid waste. However, the industrial application bottleneck of CO₂ mineralization in coal-based solid waste is still unable to break through. This paper reviews the current development of CO₂ mineralization from fly ash (FA), desulfurization gypsum (FGDG), and coal gasification slag (CGS), with the aim of exploring the reasons for their technical limitations. Firstly, this paper briefly elaborates on the pathways for CO₂ mineralization of coal based solid waste, revealing the reaction process and principles of CO₂ mineralization of coal based solid waste. Secondly, the mineralization potential and process of typical coal-based solid waste were summarized and compared to clarify the mechanism of the regulation of the process parameters on the product properties during CO₂ mineralization process. Finally, the performance of CO₂ mineralization products from coal-based solid waste was summarized, and the feasibility of the mineralization process and its environmental impact were elucidated using a Life Cycle Assessment (LCA). This paper will provide optimization suggestions on the process technology of coal-based solid waste CO₂ mineralization to promote the strategic goal of low-carbon transformation in the coal industry.