The petrological, mineralogical and chemical characteristics of the fly ash from Luohuang coal-fired power plant of Huaneng Group in Chongqing, China were studied using XRF, XRD, Siroquant, SEM-EDS, and optical microscope. Experiments of sink-float separation, magnetic separation and size grading were carried out based on analyses of those characteristics for improving the utilization rate and added value of the fly ash. As the experimental result indicated, cenospheres of 0.15% were separated by means of the water-medium sink-float separation first; then magnetic microspheres (with Fe₂O₃ content of 44.65%) were available through the wet low-intensity magnetic (260 mT) separation; finally an air classification of the remaining non-magnetic microspheres was applied to obtain microspheres with six different size fraction: 89.6, 40.2, 21.3, 12.7, 8.1 and 4.9 μm. According to the above fine separation procedure, a variety of fly ash sphere products adapting to special application fields can be acquired, improving both the utilization rate and added economic value of Luohuang fly ash. Meanwhile, the environmental pressure caused by the fly ash will be relieved effectively.

pulverized coal furnace fly ash  /  cenospheres  /  fine separation procedure  /  air classification