Analysis of limestone micromechanical properties by optical microscopy

Four dense Scandinavian limestones were analyzed to determine their mechanical properties. The generation of dust (− 10 μm) and fines (− 90 μm) during a closed circuit vertical roller mill comminution process was correlated with the calcite crystal size distributions of each limestone. Thin sections were analyzed and by means of stereology the calcite crystal size distributions for each limestone was measured. The dust generation of limestones is governed by a surface abrasive mechanism (R2 = 0.99) and the production of fines is governed by the mechanical strength of limestones (R2 = 0.99). The overall limestone degradation mechanism is predominantly controlled by the calcite cleavage planes which reduce the power consumption during the comminution process. This study is the first step in determining the influence of limestone texture on the wear rates in heterogenous raw mixes used in closed circuit comminution equipment.