Evaluation at the Circularity of Rounding Effect of Coal Particles in CWM

摘要

Evaluation of circularity of coal particles produced by a rounding method and a wet ball mill method was performed by a flow particle image analyzer, and the effect of circularity on the fluidity of CWM (Coal Water Mixture) was investigated. The rounding method employed in the present work ground off the protrusions of particles and generated fine particles. The results showed that the circularity of Bituminous coal particles produced by the rounding method was 0.97 and the CWM with Bituminous coal particle content of 70 wt percent had a good fluidity of the viscosity of 0.75 Pa centre dot s. The circularity of coal particles produced by the rounding method was the same as that by the wet ball mill method under the same coal particle content in CWM. The viscosity of CWM consisting of coal particles with the circularity of below 0.95 was increased by 0.15-0.2 Pa centre dot s from that with the circularity of 0.97. Therefore the fluidity of CWM is further improved by increasing the circularity to above 0.95. These results concludes that the present rounding method gives the same circularity of coal particles as that by the wet ball mill method, which in turn yields the good fluidity of CWM with the reduction in product cost.