Comprehensive utilization of high alumina coal fly ash under the recyclable economy model

The latest research progress on the utilization of fly ash with high concentration alumina is summarized in this paper. High-alumina fly ash has been accidentally found in central and western regions of Inner Mongolia in recent years. The high content of Al2O3 (up to 50%) and the enrichments of some useful elements, such as gallium, titanium and light rare earth make it a valuable renewable resource. A comprehensive technique route utilizing fly ash was researched and developed. After the summarize of properties of fly ash with high concentration alumina, the main methods of utilization are introduced: sintering, acid, alkali, acid and alkali combination method. The processes, productions of the four methods and the research status are described. Advantages and disadvantages of various methods are pointed out and corresponding solutions are proposed.