Breakage parameters of some minerals and coals ground in a laboratory size ceramic mill

Abstract

The kinetics of batch dry and wet grindings of calcite, barite, quartz, lignite and anthracite from feeds of sieve size - 425+300 <i>μ</i> m has been determined using a laboratory scale ceramic ball mill. The <i>S</i>₁ values obtained were the highest (0.294 min^-l) for anthracite and the lowest (0.071 min^-l) for quartz when ground dry. However, the wet grinding of these materials

gave higher <i>S</i>₁ values by a factor of 1.28 for calcite, 1.15 for barite, 1.25 for quartz, 1.11 for lignite and 1.07 for anthracite comparing to the dry <i>S</i>₁ values. The <i>B</i>_i,j<i> </i>values also changed for all the materials ground as dry and wet. The simulations of the product size distributions for both first-order and non-first order breakage of the materials ground were in good agreement with the experimental size distributions. There is a relationship between the <i>S</i>₁ values and the γ value of <i>B</i>_i,j<i> </i>parameter; i.e., <i>S</i>₁ values increase when y values decrease, indicating that faster breakage rates of top sizes produce more fines in the finer size distribution region (-150<i>μ</i>m).