Resource utilization of solid waste carbide slag: a brief review of application technologies in various scenes

China is the largest producer and consumer of calcium carbide in the world. The calcium carbide industry is an indispensable industry to support the basic life of people. The huge production capacity of calcium carbide is accompanied by a large number of solid waste carbide slag. Due to the immature treatment technology of carbide slag, a large number of carbide slag are stacked on-site, resulting in land occupation, air-drying, easy take-off ash, and pollution of the environment and water resources. In China, calcium carbide is mainly used to produce acetylene and further utilized, 80% of which is used to produce polyvinyl chloride (PVC). A large amount of carbide slag is not used, while only a small part is used in the traditional building materials industry, flue gas desulfurization, sewage treatment, etc., however, the economic benefits are poor. Therefore, converting the solid waste carbide slag produced by the calcium carbide industry into high value-added CaCO₃, CaCl₂, CaSO₄ whiskers, etc. has become a potential way to expand the development field of the calcium carbide industry and is environmentally friendly. This paper focuses on summarizing the traditional and emerging high value-added utilization technologies of carbide slag, and then introduces the application research of carbide slag in carbon emission reduction. Finally, the defects of these technologies are summarized and further research directions are prospected. This study provides basic guidance for the diversified development of efficient resource utilization of carbide slag. Graphical abstract: Diversified development of calcium carbide industry, resource utilization of solid waste carbide slag and its application of carbon emission reduction have been fully reviewed. [Figure not available: see fulltext.]