Abstract: Ultra-fine coal fly ash was prepared using the low-grade dry coal fly ash discharged from Sichuan Jianyou Bashu Power Plant as the raw material, self-developed steam flow pulverization system, low-grade superheated steam of thermal power plant and optimized system parameters determined in the early experiment.The product performance test was also made.The results show that the superheated steam pulverization process can realize the ultra-fine pulverization of low grade coal fly ash at low cost and large scale, effectively protect the glass micro-bead structure of coal fly ash and intensify the lattice distortion and amorphization of material.The prepared ultra-fine powder has good particle size distribution and morphology and its activity index is improved to above 125, meeting the technical requirement for Class A coal fly ash for preparing concrete and mortar.

Key words: Low grade superheated steam, Low grade coal fly ash, Ultra-fine pulverization