The Effect of Grinding Media Shape on the Specific Rate of Breakage
01 Dec 2008-Particle & Particle Systems Characterization (John Wiley & Sons, Ltd)-Vol. 25, pp 465-473
TL;DR: In this article, the effect of the shape of the grinding media on the breakage parameters of colemanite has been investigated in kinetic studies, and the results indicated that a faster breakage rate can be obtained by using cylinders as the ground media.
Abstract: The effect of the shape of grinding media on the breakage parameters of colemanite has been investigated in kinetic studies. In this present research, three different monosize fractions, i.e., – 425 + 300 μm, – 300 + 212 μm and – 212 + 150 μm, were used. The grinding media used for the tests were 36.5 × 36.5, 30.1 × 30.1, 25.4 × 25.4, 19.05 × 19.05 and 12.7 × 12.7 mm diameter cylinders, and 36.5, 30.1, 25.4, 19.05 and 12.7 mm diameter balls made from cast iron. The specific rate of breakage (Si) and model parameters (aT, α) were evaluated for the same quantity of cylinders, balls and feed material. The values of Si and the model parameters indicated that a faster breakage rate can be obtained by using cylinders as the grinding media. The size distributions of the products showed that the use of cylinders for grinding offers advantages for relatively coarse feeds. At shorter grinding periods, the product fineness from cylinder grinding was greater than that from ball grinding. However, after progressive grinding, the product fineness of ball grinding eventually exceeded that of cylinder grinding. The overall results indicated that the shape of the grinding media plays a determining role in the overall process.
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TL;DR: In this article, a series of batch grinding tests was carried out using the same mass of spherical balls, Eclipsoids™ and cubes to break coarse, medium and fine sizes of quartz material.
18 citations
Cites background or methods from "The Effect of Grinding Media Shape ..."
...The effect of grinding media on milling kinetics has been studied using different shapes of grinding media (Kelsall et al., 1973, Herbst and Lo, 1989, Shi, 2004, Lameck et al., 2006, Ipek, 2007, Cuhadaroglu et al., 2008)....
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...This causes the feed material to be firstly exposed to coarse grinding which is then used as a new feed for finer grinding (Cuhadaroglu et al., 2008)....
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29 Apr 2021
TL;DR: In this paper, an evaluation of Relo grinding media (RGM, Reuleaux tetrahedron-shaped bodies) performance versus standard ground media (balls) was made through a series of grinding tests, including a slight modification of the standard Bond test procedure.
Abstract: An evaluation of Relo grinding media (RGM, Reuleaux tetrahedron-shaped bodies) performance versus standard grinding media (balls) was made through a series of grinding tests, including a slight modification of the standard Bond test procedure. Standard Bond tests showed a reduction in the Bond ball mill work index (wi) of the mineral sample used in this study when using Relo grinding media. The modified Bond test procedure is based on using the standard Bond ball work index test but changing the circulating loads (350%, 250%, 150%, 100%). The comparative tests with RGM were carried out at the same number of revolutions as the grinding tests with balls at respective circulating load. The RGM charge yielded a 14% higher net undersize product than balls, which hints at improving energy efficiency and the potential for significant mining industry benefits.
3 citations
TL;DR: In this article, the effect of cooling rate on microstructure and hardness of steel ball was investigated and the results showed that faster the cooling rate is, the lower is the starting and finishing temperatures of austenite-to-pearlite transformation.
Abstract: The objective of this study was to find the effect of cooling rate on microstructure and hardness of steel ball. Steel samples of φ3 mm × 10 mm have been used under the different cooling experiments to study microstructure evolution. The microstructure is observed with optical microscopy and scanning electron microscope, respectively. The transformation temperature is determined by dilatometric curves. The results show that faster the cooling rate is, the lower is the starting and finishing temperatures of austenite-to-pearlite transformation. However, faster cooling rate has no effect on the starting temperature of martensite transformation. The prior austenite grain size increases rapidly with a higher temperature and almost remains invariant with a longer austenitization time. The hardness y of steel and cooling rates x accord with a relationship: y = 11.885x4 − 131.06x3 + 443.75x2 − 320.21x + 387.45.
3 citations
TL;DR: In this article, the underlying mechanisms of heat transfer and thermal breakage inside the ball mill are not discussed, and the authors propose a new method to solve the problem of the lack of mechanisms inside the mill.
Abstract: Ball mill is the widely used comminution device for the size reduction of iron ore particles, yet the underlying mechanisms of heat transfer and thermal breakage inside the mills heretofore are not...
3 citations
TL;DR: In this article , the authors investigated the effect of grinding media on the fine-grinding performance in the wet tumbling mill and found that cylpebs produce a slightly smaller instantaneous breakage rate than ceramic balls due to their small bulk density at the same charge volume.
Abstract: This study investigated the effect of grinding media on the fine-grinding performance in the wet tumbling mill. Comparative experiments between cylpebs and ceramic balls were conducted in a laboratory wet ball mill under various conditions, such as different total masses, total surface areas, and total numbers. The results indicated that ceramic balls produce a slightly smaller instantaneous breakage rate than cylpebs due to their small bulk density at the same charge volume. However, a larger instantaneous breakage rate can be obtained by ceramic balls with the same total mass due to the larger surface area. According to experiments related to the total surface area and total number of ceramic balls, it was found that the fine grinding of ceramic balls also needs to meet a certain break force, which is mainly determined by the diameter of the ceramic balls. Moreover, two models were developed to use ceramic balls instead of cylpebs as fine-grinding media in the wet tumbling mill based on the ball size and the ratio of the total mass of cylpebs. Cylpebs can be replaced by ceramic balls with 1.16–1.75 times the diameter of cylpebs, taking up only 76%–83% of the total weight of cylpebs. When the charge volume of cylpebs is between 20% and 35% in the wet ball mill, cylpebs can be replaced by ceramic balls of the same single mass, with the total weight of the ceramic balls being only 74%–77% of that of the cylpebs.
1 citations
References
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TL;DR: In this paper, a mathematical approach for calculating parameters relating specific rates of breakage and breakage products distribution from batch grinding a known feed for several grinding times is described, which leads to improved equipment design criteria and consistent operating correlations.
91 citations
TL;DR: In this article, the first-order specific rates of breakage and the cumulative primary daughter fragment distributions were determined in a small laboratory ball mill under standard conditions, including crystalline quartz, silicon carbide, three coals of different rank and a cement clinker.
76 citations
TL;DR: In this article, the relationship between the Bond's grindability (Gbg) and breakage parameters (Si, aT, γ and β) was examined. And the validity of the obtained relationship parameters was confirmed with correlation coefficients of 0.96, 0.92,0.90 and 0.78.
49 citations
TL;DR: The kinetics of batch grinding quartz from a feed of 600 by 425 mm to a product of 80% less than 10 mm have been determined using screening and laser diffractometer sizing for size analysis.
Abstract: The kinetics of batch grinding quartz from a feed of 600 by 425 mm to a product of 80% less than 10 mm have been determined using screening and laser diffractometer sizing for size analysis. The specific rates of breakage decreased by a factor of about three when the material became less than about 100 mm in size, but the primary breakage distribution function also changed to give proportionately more fine material, so that the grinding efficiency expressed as the development of surface area (B.E.T.) per unit of energy input did not decrease. Analysis of the shape of the particles in the 25 × 38 mm size range showed that particles of this size produced by roll crushing or by 8 minutes of grinding of a 425 × 600 mm feed were not different but at long grinding times the particles were rounded. This suggests that the breakage mechanism changes to give more chipping and abrasion and less disintegrative fracture. As the material approached the ultrafine size range it adhered to the mill case and there was no further size reduction. However, a technique for striking the mill case to dislodge the particles was successful in allowing further grinding to 40% by weight less than 2 μm.
39 citations
TL;DR: In this paper, the effect of mill speed on the limestone and the clinker samples of Goltas Cement Factory (Isparta, Turkey) at batch grinding conditions based on a kinetic model was investigated.
35 citations