Coal Grindability and Breakage Parameters

An empirical relationship of the Hardgrove Grindability Index (HGI) was established in terms of breakage parameters. In order to model particle-breakage behavior in a crusher, breakage parameters and HGI of material should be taken into consideration. Coal grindability has long been studied and empirical equations evaluating coal characteristics data have been proposed. Basically knowing the size distribution of the feed coal to the crusher and obtaining an experimental product size distribution after processing could help to model the operation conditions of the device. Breakage processes for coal have been modelled namely as pi-breakage process, pi, kappa-breakage process and pi, kappa, omega-breakage process (pi: proportion selected for breakage in an assembly, kappa: number of breakage in a breakage operation omega: coefficient of size dependence). Having evaluated the breakage model for any crusher, the size distribution of crushed coal and its HGI could be related to each other. An empirical method between HGI and p proposed in this study was in good agreement with the experimental results. Experimental analysis of the crusher feed coal yielded an average HGI of 66 and the predicted HGI values were in the range of +/- 10% of this average by employing the proposed method. As a second contribution of the proposed method, the stabilization of the size distribution of the crushed coal can be achieved with a decision mechanism for the plant operators about communition process.