Abrasivity and grindability study of mineral ores

The results of the milling experiments of different mineral ores and laboratory wear testing with different abrasives have shown that the abrasivity of treated materials does not depend only on their hardness, but, to a great extent, on the particle shape of the materials. The grindability of materials milled by collision depends on the properties of materials as well on the treatment parameters (specific treatment energy). The aims of this investigation were (1) to study the abrasivity and the grindability of different minerals (granite, quartzite, etc.) and (2) to predict the relative wear resistance of the materials prospective for the grinding media of milling equipment, using a centrifugal type impact wear tester. Experiments conducted with abrasives of different hardness and with particles of different shape have shown that the wear rate of materials used as wear resistant materials in grinding devices depend more on the angularity of abrasive particles than on their hardness. It was shown that the grindability depends more on the composition and properties (fracture toughness, homogeneity of the structure) than on the hardness of the mineral ores. The main size reduction occurs at first collision, later in the multiple milling of mineral materials particle rounding takes place. The angularity parameter has good correlation with the wear rate in the case of the studied commercial steels as well as with metal matrix composites. Experiments with cermets showed that erosion does not practically depend on abrasive particle shape.