An Experimental Study on the Grinding Rate Constant of a Ball Mill
10 Jan 1998-Journal of The Society of Powder Technology, Japan (The Society of Powder Technology, Japan)-Vol. 35, Iss: 1, pp 12-17
TL;DR: In this paper, the effects of the ball diameter and the feed size on the rate constant were investigated when the mass of balls and feed size were constant and the rotational speed of the mill were constant.
Abstract: The grinding rate constant is one of the important factors needed to estimate or evaluate a grinding process. It has been found that the decreasing rate of the feed size was described by a first-order equation in the initial grinding stage of various mills.In this study, grinding tests were carried out on silica glass using a ball mill, and the grinding rate constant of feed size decrease were measured. The effects of the ball diameter and the feed size on the rate constant were investigated when the mass of balls, the mass of feed and the rotational speed of the mill were constant.As the result of the tests, the grinding rate constant could be expressed by modifying the equation which was proposed by Snow as the function of ball diameter and feed size.
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TL;DR: In this article, an experimental investigation was carried out on the ultra-fine grinding of inorganic powders using a stirred ball mill and the power consumed in the grinding process was measured, and the comminution coefficient was examined, based on an analysis of the relationship between the experimental specific surface area and the particle size distribution of ground products.
61 citations
TL;DR: In this paper, the authors investigated the effects of feed size and ball diameter on the grinding rate constant of the materials used when the mass of balls, mass of feed, and the mill's rotational speed were constant.
57 citations
TL;DR: In this article, an experimental investigation on grinding mechanism for calcite used in a stirred ball mill was carried out and the effect of grinding aids on particle size distribution and grinding efficiency was investigated.
Abstract: An experimental investigation on grinding mechanism for calcite used in a stirred ball mill was carried out. The slurry concentration and the amount of grinding aids were chosen as main experimental factors of the grinding process. The effect of grinding aids on particle size distribution and grinding efficiency, defined as the increases of specific surface area per the specific grinding energy, was investigated. It was demonstrated that the grinding rate for calcite could be improved by addition of grinding aids. The grinding energy efficiency by adding a specific grinding aids was improved approximately 45.2% in comparison with and without grinding aids (n=700rpm, J=0.7, dB= 1.0 mm, Cs=60wt%).
9 citations
TL;DR: In this article, the authors investigated the effect of sample concentration on the ultra fine grinding rate of calcite powder in a stirred ball mill with respect to slurry concentration and found that the lower the sample concentration, the better the grinding rate.
Abstract: Wet ultra fine grinding of a calcite powder has been investigated in a stirred ball mill with respect to the effect of slurry concentration. The grinding rate on the submicrometer range was measured and the grinding constant on the grinding rate (K) in the grinding kinetics equation was examined. It is observed that the grinding rate for calcite in the submicrometer size range is different for different sample concentrations. It was found that the lower the sample concentration, the better the grinding rate. Furthermore, an empirical grinding rate (K)-sample concentration model provides a good fit to the grinding results under the experimental conditions investigated. The K improved by a maximum of 1.6 times at 700 rpm and 19.1 times 300 rpm for various sample concentrations, respectively. We confirmed that sample concentration affected the grinding rate of the submicrometer-size powder during the grinding process.
8 citations
TL;DR: In this article, the behavior of ground copper powder for copper-carbon nanotube (copper-CNT) nanocomposite fabrication during high-speed planetary ball milling was investigated.
Abstract: The behavior of ground copper powder for copper-carbon nanotube (copper-CNT) nanocomposite fabrication during high-speed planetary ball milling was investigated because the study of the behavior characteristics of copper powder has recently gained scientific interest. Also, studies of Cu/CNT composites have widely been done due to their useful applications to enhanced, advanced nano materials and components, which would significantly improve the properties of new mechatronics-integrated materials and components. This study varied experimental conditions such as the rotation speed and the grinding time with and without CNTs, and the particle size distribution, median diameter, crystal structure and size, and particle morphology were monitored for a given grinding time. We observed that pure copper powders agglomerated and that the morphology changed with changing rotation speed. The particle agglomerations were observed with maximum experiment conditions (700 rpm, 60 min) in this study of the grinding process for mechanical alloys in the case of pure copper powders because the grinding behavior of Cu/CNT agglomerations was affected by the addition of CNTs. Indeed, the powder morphology and the crystal size of the composite powder could be changed by increasing the grinding time and the rotation speed.
5 citations
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148 citations
TL;DR: In this article, the influence of changes in ball diameter on the grinding behavior of trace quantities of quartz within an environment of calcite in a small continuous wet ball mill has been studied.
61 citations
TL;DR: In this article, an analysis of the selection function for mills using balls as grinding media is presented, assuming that a particle caught by two colliding balls will be ground only if the ball impact generates or activates at least one single crack within the particle causing the fragmentation.
25 citations
TL;DR: In this article, the specific rate of breakage of particles is described by the equation Si=a·xia·Q(z), where Q(z) is the probability function ranging from 1 to 0, which has been used by Austin for a tumbling ball mill.
Abstract: Grinding experiments on the sieved-size fraction of silica sand in a planetary mill are carried out. It is found that for large balls (≥∅4mm), the breakage of she fine size fraction can be described by first-order law, but when the particle size is larger than the ball size, the breakage is not of the first-order, but even for smaller balls, the breakage is completely non-first-order. Reasons for this non-first-order breakage are experimentally investigated and discussed. The specific rate of breakage of particles is described by the equation Si=a·xia·Q(z), where Q(z) is the probability function ranging from 1 to 0, which has been used by Austin for a tumbling ball mill. In this equation, S has a maximum value, and the particle size of the maximum is related to the ball diameter by xm=k1dB, where k1=0.05 irrespective of the specific gravity of the balls. In another words a 20:1 ball diameter/particle size ratio can give the optimum grinding condition for planetary milling, which is found to be the same as in stirred ball milling, but it is different from tumbling ball milling and vibration ball milling. The effect of the diameter and the specific gravity of balls can be expressed as a=k3(ρB/dB0.35).
13 citations
TL;DR: In this paper, a ball mill grinding was carried out on silica-glass to get submicron particles and to evaluate the fine or ultra-fine grinding process of materials.
Abstract: A demand for fine or ultrafine particles is increasing in many industries. It is well known that the energy efficiency in a grinding process decreases with a decrease in produced particle size and with an increase in grinding time or input energy. Therefore, the evaluation of fine or ultrafine grinding of materials is essential. In this paper, ball mill grinding was carried out on silica-glass to get submicron particles and to evaluate the fine or ultrafine grinding process. The mill used was made of alumina with a diameter of 144mm and the inner length of 130mm. Its volume was about 2.1 liters. The grinding balls were also alumina with a diameter of 20mm. The effects of the mass of feed and the mass of balls on fine grinding were investigated at a constant rotatioal speed of the mill. The progress of grinding was evaluated by the mass of submicron particles and the surface area of ground porducts.The following results were obtained:(1) The final median particle size of ground products was independent of the mass of feed or balls.(2) The optimum grinding condition for production of submicron particles changed with grinding time in an early stage and it became constant in the later stage.(3) The surface area was proportional to the mass of submicron particles in the ground products.
12 citations