Multifractal characterization of gangue particle size distribution structure during ball milling process

Abstract

This study is focused on the fractal characteristics of gangue particle size distribution(PSD) during ball milling process, taking mudstone, sandstone , and limestone gangue as the research object with multifractal theory, laser scattering-based particle size analysis , scanning electron microscopy (SEM), X-ray diffractometry (XRD) and other mesoscopic methods. The multifractal characteristic parameters of gangue PSD under different milling time and their correlation with the mesostructure are analyzed. The results show that the PSD of three gangues have different fractal characteristics and the multifractal parameters have stage distribution characteristics with time. The multifractal characteristic parameters of gangue, such as D(0) D (2), Δα 、 Δf , initially increase and then decrease with the increase of ball milling time, and reach the maximum value in 10-20 min. The heterogeneity of gangue PSD and the microscopic mechanism of multifractal parameter changes are revealed by examining the correlation between multifractal parameters and gangue morphology in fragmentation form. The change of gangue morphology is consistent with the change of multifractal parameters of PSD structure during ball milling process. • Particle size distribution multifractal characteristics of gangue have phased characteristics during ball milling. • Shape coefficient is highly consistent with the multifractal parameter of particle size distribution . • Particle breakage form is the main factor of particle size distribution and meso-structure change. • With an increase in milling time, the main forms of crushing transition from impact to extrusion and friction.