Estimation of specific rate of breakage parameters to optimize the industrial batch ball mill

Abstract

Objective of this study is to investigate and optimize an industrial batch ball mill by using the population-balance modeling. Experimental work involved taking samples after different grinding times from an industrial batch ball mill. The parameters of specific rate of breakage and breakage function were calculated from the population-balance modeling equation using the back-calculation method. As the time of grinding increases, the specific rate of breakage increases to a peak value at 6 h grinding, and then decreases. One of the main reasons for the above is that the particle size decreases continuously in a batch grinding process; however the ball size remains constant. Therefore, allowing an excessively long grinding time without changing the media size is an inefficient method of production of fines. The specific rate of breakage values indicated maximum selection at the end of 6 h. Any further grinding after this time is considered inefficient. In order to obtain finer particles, the samples were taken from the industrial ball at after 6 h milling and fed to a laboratory stirred media mill obtaining the desired product within 15 min of grinding.