Studies in vibration milling of aluminium powder
TL;DR: In this article, the effect of feed size, additive concentration, weight ratio of the feed to grinding media and ball filling on the grinding characteristics was studied. But the results were limited to the case where the feed size was an insignificant variable in the range studied.
Abstract: Atomized aluminium powder is ground in the presence of stearic acid in a laboratory vibration mill at different conditions in order to study the effect of feed size, additive concentration, weight ratio of the feed to grinding media and ball filling on the grinding characteristics. Feed size is found to be an insignificant variable in the range studied. While a stearic acid concentration of about 3% is desirable, higher concentrations result in a reduction in the rate of grinding. A lower weight ratio assures a higher rate of grinding whereas higher ball filling is preferable considering the increased production of fines.
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01 Jan 2010
TL;DR: In this paper, the authors proposed a geometrical exposure model based on the available surfaces of gold grains and type of access of reagents to the gold grains in the case that they are locked in a particle and accessible only through pores and fractures.
Abstract: Leaching of gold ore has been more investigated as a "chemical' reaction that depends on some "chemical" parameters such concentration of reagents, pH, e t c . , while considerations to the "physical' phenomena of liberation and exposure of gold grains has been limited in the literatures. The development of new phenomenological models of grinding, liberation and leaching of gold ores in an interconnected framework which considers the particular behavior of gold in any of the processes and could relate these processes to each other is the main objective of this thesis. By dividing the bulk ore into mineralized and non-mineralized particles and by defining different breakage patterns for them and by taking into account the size distribution of the gold grains in the ore, the grinding model proposed in this thesis can predict the distribution of gold within the size intervals of a ground gold ore. The model was found to be able to reproduce fairly well the results of batch grinding tests of a gold ore. Once the amount of the various gold grain sizes in size fractions of the ground ore is estimated by the grinding model, a geometrical exposure model, developed for this thesis, provides an efficient link between the grinding and the liberation process to predict the way gold is exposed to the leaching environment. The proposed leaching model is based on the available surfaces of gold grains and type of access of reagents to the gold grains in the case that they are locked in a particle and accessible only through pores and fractures. The leaching model uses only two parameters and was found sufficient to represent the behavior of gold in various size fractions of the samples during a leaching process. Although any of the three proposed models are new and could find new applications, the main contribution of the thesis is the introduction of an integrated and interconnected methodology for estimation of metallurgical performances of gold processing. The effect of disturbances such as a change of feed grade, grinding mill feed size distribution and/or distribution of gold grain sizes in the ore on the dissolution of gold can be readily studied with the integrated simulation of the grinding-liberation-leaching processes.
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TL;DR: In this article, the effect of grinding aids on the grinding characteristics of aluminum in a vibration mill under an inert atmosphere of nitrogen has been investigated and it was found that the use of grinding aid is essential in grinding of atomized aluminum.
Abstract: Fine aluminum powder is widely used in making paints, printing inks, slurry explosives, pyrotechnic chemicals etc. Hence the production of aluminum powder is highly important. In this paper the effect of grinding aids on the grinding characteristics of aluminum in a vibration mill under an inert atmosphere of nitrogen has been investigated. It is found that the use of grinding aids is essential in grinding of atomized aluminum. Among four different grinding aids, stearic acid appears to be the best grinding aid.
4 citations
TL;DR: In this article, the results of 300 experimental runs on vibration milling of soapstone, graphite, cXte, magnesite, rock phosphate, granite and zirX sand covering particle size range of (−0.25+0.10) to (−1.00+ 0.80) mm, density range of 2.29−4.59 g/cm3, hardness range of 1-7 Mho's hardness number and surface energy range of 4.50−38.66 kgf m/m2, are presented.
Abstract: The results of 300 experimental runs on vibration milling of soapstone, graphite, cXte, magnesite, rock phosphate, granite and zirX sand covering particle size range of (−0.25+0.10) to (−1.00+ 0.80) mm, density range of 2.29−4.59 g/cm3, hardness range of 1–7 Mho's hardness number and surface energy range of 4.50–38.66 kgf m/m2, are presented. The results obtained were used to determine (1) the effect of grinding characteristics (feed weight, feed particle size, ball charge, density of ball material, weight ratio and mill filling ratio), (2) the effect of material characteristics, (3) the comparative performance of vibration mill and ball mill, and to compare the specific surface areas produced by grindability apparatus, vibration mill and ball mill. Correlations for grinding energy consumption and rate of grinding are presented.
3 citations