Ultra-fine grinding of inorganic powders by stirred ball mill: Effect of process parameters on the particle size distribution of ground products and grinding energy efficiency

A series of wet grinding experiments have been carried out using a stirred ball mill to systematically investigate the effect of processing conditions on the final particle size distribution and grinding kinetics. A sub-micron particle size down to 350 nm was achieved, while the grinding energy efficiency or enhanced grinding rate was shown to be improved with the addition of grinding aids and with the use of smaller grinding media. A simple exponential relation was then proposed to quantitatively describe the observed grinding behavior by introducing the production rate constant,K. It is suggested that by usingK as a guideline, ways of improving the grinding energy efficiency can be established, e.g. use of smaller grinding media, choosing larger particle size class materials, etc.