Particle Size Variation Characteristics of Outburst Coal Under Repeated Impact Crushing

This experiment adopted impact crushing method to crush different destroyed-type coal samples, and the impact times were stepped increased, then the fragmentized coal was sieved and weighed. Based on a large amount of experimental data, this article established particle size distribution function, explored the applicability of coal crushing energy surface theory under the condition of repeated impact, and discovered the law of major particle size distribution. The results showed that the particle size distribution function fitted the experimental data very well. When the number of impact was less, it was proved that coal surface crushing energy work theory was applicative to describe the crush of coal. The particle size of crushed coal were not decreasing with the increasing of impact times, it concentrated in a certain particle size range, and the certain particle size range showed differences among coal samples.