Experimental study on non-linear behavior of breakage rates due to fines generation in wet batch milling

Abstract

The mechanism of wet grinding is still an object of interest and the better estimation of grinding kinetics provides greater benefits in terms of energy saving. The primary objective of this paper is to investigate reasons and causative factors contributing to nonlinearities in breakage rates for wet grinding systems. In ball milling the breakage rates vary mainly with the size distribution of the powder generated in the mill. 1st order and 2nd order breakage kinetics have been considered in this work to provide detailed insight into the mechanism of milling during wet grinding operations. Two methods have been used for breakage rate parameter estimation: cumulative input procedure and incremental input procedure. These methods are compared against each other to get a better understanding of how breakage rates evolve. Three different ore types are used as natural and monosized feeds. Results derived from both methods have been lucidly explained. The 2nd order specific selection functions, based on incremental inputs of specific energy, displayed inherent nonlinearities in the wet grinding process. It was observed that the breakage rates varied with the size consist in the mill for all three ore types.