Enrichment and utilization of residual carbon from coal gasification slag: A review

Coal gasification is a clean and effective method for converting coal into syngas, which is mainly used in fuel and chemical industry. However, the process of coal gasification produces copious amounts of solid waste, that is, coal gasification slag, which is very harmful to the surrounding environment, and then to people's lives and health. The residual carbon is the product of incomplete coal gasification and has high economic utilization value in coal gasification slag. Recovery and utilization of residual carbon is an effective method for the comprehensive treatment of coal gasification slag. This study discusses the current methods of recovering residual carbon from slag, such as the physical, chemical, physicochemical and special separation methods, based on the properties of coal gasification slag, further the advantages and disadvantages of each method are compared. Moreover, the utilization of residual carbon as fuel or for the preparation of materials are discussed in detail. Finally, research and development recommendations for the future study of residual carbon in future are discussed based on existing limitations in the field.