Grinding of ceramic raw materials by a standard Bond mill: Quartz, kaolin and K-feldspar

Abstract

The kinetics of batch dry grinding of ceramic raw materials, which are quartz, kaolin and K-feldspar, from the feeds of sieve sizes -3-350+2-360, -2-360+1.400, -1.400+0.850, -0.850+0.600, -0.500+0.425 and -0.300+0.212 mm have been determined using a Bond mill with a mixture of five ball sizes. The mill used was a size of 30.5 cm diameter, 30.5 cm length, providing a total mill volume of 22 272 cm3 with a total mass of 22 648 g steel ball mixtures of 38.10, 31.75, 25.40, 19.05 and 12.70 mm diameters, occupying 22% of mill volume and with a speed of rotation of 70 rpm. The specific rates of breakage (Si) and primary breakage distribution (Bij) values, called grinding breakage parameters, were determined for those feed size fractions to predict the product size distributions by simulation for comparison to the experimentally obtained data. As the feed sizes increase, the Si values also increase, that is, faster breakage values from higher to lower values were in the order of quartz, K-feldspar and kaolin by comparison with their a values. The Bij values obtained for these minerals were different in terms of characteristic fineness factor, ?. Thus, kaolin produced more fines, while K-feldspar and quartz produced less fines in the mill. In other words, the simulations of product size distributions for these minerals were in good agreement with the experimental data using a ball mill simulation program, called PSUSIM. However, the slowing down effect in the mill started earlier than expected for the minerals studied, unlike the laboratory size ball mill used extensively in our studies. Nevertheless, there exist linear relationships between the simulated time (?) and experimental time (t) for these minerals. © 2005 Institute of Materials, Minerals and Mining and Australasian Institute of Mining and Metallurgy.