Comminution Behavior of Porous and Non-Porous Materials
Comminution behavior of porous materials differs substantially from non-porous ones. It is strongly affected by porosity. Therefore, the aim of this work is to make a comparison between the comminution behavior of porous and non-porous materials. It is applied on sandstone and limestone samples as porous materials, and white marble and quartz as non-porous ones. The study was performed using a laboratory scale ball mill with 16 cm inside diameter and 14 cm length, which loaded with 50% of its volume by steel balls of 19 mm, diameter. The operating mill speed is kept constant at 79 rpm corresponding to 70% of its critical speed. Time of grinding was varied from 0.5 to 5 minutes while the other affecting operating parameters were kept constant.
Comminution performance was measured by both the specific surface area as well as breakage rate function of the product.
The obtained results showed that the porous materials were ground faster than the non-porous ones. The results cleared also that the rate of grinding of a porous material increases with high rate at the beginning short times of grinding then increases moderately after the liberation of voids.