Simulation of washability and liberation information from photographs

Abstract

Imagine that a sample of coal could be crushed unlimited times to the same or different top size; a different washability would be obtained for each crushing experiment. Depending on the size and distribution of the raw coal components (say vitrinite, inertinite, and mudstone), better yields for a low ash product are obtained as a top size is approached that is the same or smaller than the components that need to be liberated. As the top size approaches the size of the components that need to be liberated (or smaller), near density material will start decreasing and the density differences between the components that need to be separated will become larger, because mostly "clean" single component particles are produced, that have widely different densities. As the virtual particle size decreases, the concentration or yield of the low ash product increases to a maximum, as the macerals are completely liberated from mineral matter In this paper a method is proposed to predict washability characteristics by simulating how coal will behave when crushed to different top sizes and with different virtual particle size distributions, from photographs.