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A quick method for Bond work index approximate value determination

Todorovic D., Trumic M., Andric L., Milosevic V., Trumic M.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 1

321--332

EN

The Bond work index is a measure of ore resistance to crushing and grinding and is determined using the Bond grindability test. Its value constitutes ore characteristic and is used for industrial comminution plants designing. Determining the Bond work index value is quite complicated, time-consuming and requires trained operating personnel and therefore is subjected to errors. A quick method for the Bond work index approximate value determination, which is based on the first order grinding kinetics, is presented in this paper. Comparative experiments for the Bond work index value determination using the standard and quick procedures were carried out on samples of limestone and andesite, and on composite samples containing both ores in different mass proportions. This quick procedure can be performed with an arbitrary number of milling cycles, depending on the desired accuracy.

2

Comparative analysis of process parameters of talc mechanical activation in centrifugal and attrition mill

Andric L., Terzic A., Acimovic-Pavlovic Z., Pavlovic L., Petrov M.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 2

433--452

EN

The efficiency of talc mechanical activation by means of two different mechano-activators - centrifugal and attrition mill is investigated in this study and the comparative analysis of the characteristics of obtained talc powders is presented. A new approach for obtaining high-grade talc concentrate with low Fe2O3 content is achieved through effect of mechanical activation of talc accompanied by hydrometallurgical process. The applied mechanical activation process conditions of ultra-centrifugal mill were defined by number of rotor revolutions, sieve mesh size, and current intensity. These operating parameters of the ultra-centrifugal mill were variable. Ultra fine grinding of talc in attrition mill (attritor) was carried out in various time intervals - from 5 to 15 min. The following technological parameters of the mechanical activation were monitored: time of mechanical activation, circumferential rotor speed, capacity of ultra-centrifugal mill, and specific energy consumption. The investigation was based on a kinetic model. The structure and behavior of activated samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, and differential thermal analysis (DTA).

3

The optimal ball diameter in a mill

Magdalinovic N., Trumic M., Trumic M., Andric L.

Physicochemical Problems of Mineral Processing

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2012

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Vol. 48, iss. 2

329-339

EN

This paper covers theoretical and experimental explorations for the sake of determining the optimal ball charge in mills. In the first part of the paper, on the basis of the theoretical analysis of the energy-geometric correlations, which are being established during the grain comminution by ball impact, as well as on the basis of the experiment carried out on grinding quartz and copper ore in a laboratory ball mill, there has been defined a general form of the equation for determining: the optimal ball diameter depending on the grain size being ground; and the parameter of the equation through which the influence of a mill is being demonstrated; then the parameter of the grinding conditions; and the parameter of the material characteristics being ground in relation to the ball size. In the second part of the paper, the process of making up the optimal ball charge has been defined providing the highest grinding efficiency, as well as its confirmation by the results of the experimental explorations.