A study on density-ash correlation of various size fractions of raw coal feed and cleaned products in preparation of thermal coal

Based on the original data of the raw coal feed and products obtained through washing with a stand-alone H.M. cyclone, 48 regression equations expressing the positive density-ash correlations of different coal size fractions with a nearly the same intercept a and slope b are derived through regression analysis, and the results obtained are checked through t-test with the method of mathematical statistics. Result of analysis shows that the density-ash regression equation of the 50-0.5 mm composite size raw coal feed with a density ranging from 1.60-2.10 kg/L can be used to predict the density of various size factions of coal.