A mini review on the separation of Al, Fe and Ti elements from coal fly ash leachate

The electricity demand is increasing rapidly with the development of society and technology. Coal-fired thermal power plants have become one of the primary sources of electricity generation for urbanization. However, coal-fired thermal power plants produce a great amount of by-product coal fly ash every year. Coal fly ash disposal in landfills requires a sizable space and has negative environmental impacts. Therefore, it is crucial to develop new technologies and methods to utilize this enormous volume of solid waste in order to protect the environment. In this review, the fundamental physical and chemical characteristics of coal fly ash are introduced, and afterward the disposal policies and utilization ways of coal fly ash are discussed to gain a comprehensive understanding of the various ways this waste. The leaching of valuable metals in coal fly ash and the extraction of metal elements in leachate under different conditions are also summarized. Furthermore, the possibility of coal fly ash to serve as a supplementary source for mineral resources is analyzed, providing a basis for its extensive use as a raw material in the metal industry in China and worldwide.