The fractal characteristic of particle size distribution in coal grinding process

Fractal particle size distribution (FPSD) is a powerful tool for characterizing particle population. Researchers have used it to characterize the particle population of bulk material in nature and crushed form. In our work a coal has been comminuted in an experimental ball mill and the ground product on different grinding time are characterized by FPSD. It was discovered that the fractal dimension (D) of FPSD of the product at different grinding time was similar, which denoted that the fractal dimension of FPSD can be used to characterize the self-similarity of coal comminution. For same maceral constituent the D value of FPSD was almost unchanged with the grinding time, but distinct for different marcral particles. The mineral particle has smallest D and that of inertinite is larger than vitrinite's. It reflects the distribution of macerals in coal.