Research status and prospects of utilization technologies of slag from coal gasification

Coal gasification technology has become an important part in China's energy strategy. However, a great amount of slag has been generated due to this technology, which requires urgent development of resource utilization technology to consume and reuse the slag largely. Considering that different mineral phases of coal ash content will change with the temperature in the gasifier, and based on the investigation and summarization of this change, the physicochemical reaction process of various mineral phases in gasifier is described and the decisive impact of coal ash content on final morphological characteristics of slag from coal gasification is also revealed. The research on the constituents of carbon residue in the slag and their features of change shows that final utilization approaches of the slag are significantly influenced by carbon residue. Additionally, by analyzing current research status of utilization technology of coal gasification slag, it is pointed out that the utilization as building material and mixed combustion with circulating fluid-bed raw material are the most popular approaches for slag utilization. Finally, the prospects of utilization technology for slag from coal gasification are proposed and some utilization approaches are suggested, including using as raw material of concrete or cement and being backfilled underground.