不同硬度块煤冲击破碎后粒度分布特征试验研究

Experimental study on particle size distribution characteristics of coal with different hardness under impact crushing

为了探究不同硬度的块煤在冲击破碎作用下破碎后的粒度分布特征,利用坚固性系数实验装置,对4种不同硬度的块煤进行了冲击破碎试验研究,试验结果表明:破碎功与块煤破碎后的新增表面积成线性关系,折算直径与破碎功成反比。块煤破碎后具有自相似特征,其分形维数能够反映煤的破碎程度,分形维数越大,破碎效果越好,坚固性系数f与分形维数D呈线性关系。颗粒在破碎过程中,大颗粒因周边小颗粒的存在而受到缓冲作用,使得较小颗粒由于挤压作用而优先破碎,小颗粒的缓冲作用增强了大颗粒抵抗破碎的能力,因此较小颗粒反而更容易破碎。

In order to explore the particle size distribution characteristics of lump coal after crushing with different hardness under impact crushing,the impact crushing experiments of four different hardness lump coals were carried out by using the Protodyakonov coefficient measuring device.The experimental results show that the crushing energy is linear with the newly added surface area after the lump coal is broken,and the converted diameter is inversely proportional to the crushing energy.The lump coal has self-similar characteristics after crushing,and its fractal dimension can reflect the crushing degree of coal.The larger the fractal dimension,the better the fracture effect,and the solidity coefficient f is linear with the fractal dimension D.During the crushing process,the large particles are buffered by the presence of surrounding small particles,so that the smaller particles are preferentially destroyed due to extrusion,and the buffering effect of small particles enhances the ability of the large particles to resist crushing,so the smaller particles are more likely to be broken.