2.1 Terms Associaed with Ball Mill Operation 2.1.1 Grindability (G): Grindability is the number of net grams of screen undersized product per revolution [1]. The chief purpose of study of the grindability is to evaluate the size and type of mill needed to produce a specified tonnage and the power requirement for grinding. Detailed prediction of
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There is a Play of money in ball mill sizing. What are the problems plant people faces if we will go with Ball Mill selected on the basis of work index 15.36kWH/t. If there is a case of a overgrind, then how it can be controlled through closed circuit hydrocyclone. How overgrinding of …
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Six tests were carefully performed with both mills using the same aggregate rock sample and with the same method of grindability testing based on Fred Bond's Ball Mill Grindability Work Index (BWi ...
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Although it was developed nearly 50 years ago, Bond's method is still useful for calculating necessary mill sizes and power consumption for ball and rod mills. This paper discusses the basic development of the Bond method, the determination of the efficiency correction factors based on mill dimensions and feed characteristics, and the application of the results to designing grinding circuits.
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In the same way Fig. 3 indicates that an 800-hp motor and a 101/214 or 10.5′ by 14′ Ball Mill is required. Following is a condensed tabulation of the above selections. Sizing a Ball or Rod Mill Sizing a Crusher using >1200 Wi of Ores from Database. For your convenience, this manual lists over 1200 work indexes.
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Request PDF | Product size distribution function influence on interpolation calculations in the Bond ball mill grindability test | Bond standard procedures are often used in design of comminution ...
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condition of 250% circulating load is obtained. This grindability test is conducted in a Bond ball mill of ΦD/L= 0.3048/0.3048 m dimensions at the speed of 70 rpm. The mill is loaded with 21.125 kg standard sized balls and 700 cm3 of grinded materials to under 3.35 mm. The test procedure takes from 7 to 10 grinding cycles with the
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CORRELATION BETWEEN BOND WORK INDEX AND . 2014 6 27 ball mill grindability. The test mesh used was 100 mesh P > 14 16 . The Bond work index W i was calculated from Equation 2 W i = 44.5/ P 1 0.23 X Gbp 0.82 10/ P 80 0 5 0.5± 10/ F 80 2 Where F 80 is the size in µm at which 80 percent of the new feed to ball mill passes
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Relation of Bond rod mill work index and crushing work index. Similar to the ball mill work index, the rod mill work index is a tumbling test that includes both attrition and abrasion breakage mechanisms. Unlike the ball mill work index, the size of the feed to a rod mill test (10 mm–12 mm) is closer to the size of the crushing test.
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Grindability of binary ore blends in ball mills - ScienceDirect The paper investigates the size reduction of blends of materials with different grindabilities in a Bond ball …
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The sample size in each case, considering the largest particle size, was enough to perform the series of Bond ball mill grindability tests separately (see Section 2.2), but not enough to perform the series of Bond rod mill grindability tests separately for each sample (see Section 2.3). Accordingly, it was decided to blend and homogenize the ...
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Berry and Bruce (1966) and Horst and Bassarear (1977) devised an approximate procedure comparing the grindability data of an unknown ore with a reference ore whose grindability data are known and determined in a Bond ball mill. The test is performed on samples of size −1.651 mm in any laboratory mill with balls.
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In spite of the important developments in recent decades with improved characterization, modeling and simulation approaches applied to ball mills (Austin et al., 1984, Herbst and Fuerstenau, 1980, Tavares and Carvalho, 2009), the Bond ball mill grindability test retains a significant part of its original importance as a convenient and ...
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of the Bond ball mill grindability test. For all model based methods, a reliable method to calculate mill power draw for a given mill is required for the calculation of power draw. Morrell (1996) proposed a mathematical model for autogenous, semi-autogenous and ball mills which is based on the motion of grinding charge inside the mill.
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The ball mill work index laboratory test is conducted by grinding an ore sample prepared to passing 3.36 mm to product size in the range of 45-150 µm, thus determining the ball mill w i .
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5 where: Mib and Mia are the "fine" and "coarse" laboratory grindability metrics, respectively, P80 and F80 are the milling circuit product and feed sizes, respectively, µm, K is a calibration parameter of 0.95 for pebble crushing or 1.0 for no pebble crushing Barratt model: Barratt (1979) published a three-parameter model based on a copper porphyry mine
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sizing of ball mill based on grindability - mill for sale . Calculate and Select Ball Mill Ball Size for Optimum . Ball Mill Loading - Dry Milling - Paul O. Abbe . Ball Mill Presentation - Scribd . fritsch-international - Home – fritsch.de . Ball Mill Output Feed Size - womenofsubstanceawards .
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sizing of ball mill based on grindability indeand in . sizing of ball mill based on grindability indeand in cameroon brazil tin ore processing plant 1 pilot plant for the processing of a complex tin ore a contribution towards geometallurgy in beneficiation edgar schach1 flavio padula1 lucas pereira1 robert m ckel1 doreen ebert1 markus
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Ball Mill Power Calculation Example #1. A wet grinding ball mill in closed circuit is to be fed 100 TPH of a material with a work index of 15 and a size distribution of 80% passing ¼ inch (6350 microns). The required product size distribution is to be 80% passing 100 mesh (149 microns). In order to determine the power requirement, the steps ...
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ore sample will be tested in a standard Bond ball mill grindability test (aka. the Bond ball mill work index test) with a closing screen size chosen so the test product P80 closely matches the survey product P80. Depending on the plant configuration, it may be possible to also collect this raw ore sample without shutting down any grinding mills.
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One is the Hardgrove grindability index and the other the Bond work index. The Hardgrove index is determined using the ASTM method D 40971. It involves grinding 50g of the material, e.g. coal, of specified size (1630 mesh cut) in a specified ball-and-race mill for 60 revolutions.
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The grindability tests carried out using a standard Bond ball mill allowed, in turn, determining the product particle size distribution of the processed ore as a function of both grinding time and work input. Results from such tests were used to compute the Bond ball mill work index characterizing the chalcopyrite ore analyzed here.
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This Grindability Test or Bond Ball Mill Work Index Procedure is used to determine the Bond Work Index of minus six mesh or finer feed ore samples. These equation application methods are used to process <1/2″ ore samples in a Ball Mill using a standard ball charge.. Below describes in general terms the Bond Work Index Procedure used by a Professional Metallurgical Testing Laboratory.
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sizing of ball mill based on grindability indeand Bond Work Index Formula Equation 911 Metallurgist. Jul 15 2013 In the standard A C closed circuit ball mill grindability test the work index is found from. where Pi is the opening in microns of the sieve mesh tested and Gbp is the net grams of mesh undersize produced per revolution of the 12 ...
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The standard Bond ball mill grindability test is a closed circuit dry grinding test with a 250% circulating load. The standard procedural outline of the test is stated in (Bond) 1961. The work index for a ball mill, Wi, is then calculated from the following equation. [7] where P is the closing sieve size ( …
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Ball Size vs. Grindability. It has been recognized that the grindability of an ore in a ball mill is a function of both feed and mill parameters: Work index, W i; Largest particle size and size distribution; Density of solids and slurry; Mill diameter; Rotational speed; Rowland and Kjos (1980) defined the largest ball size needed based on these ...
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Although it was developed nearly 50 years ago, Bond's method is still useful for calculating necessary mill sizes and power consumption for ball and rod mills. This paper discusses the basic development of the Bond method, the determination of the efficiency correction factors based on mill dimensions and feed characteristics, and the application of the results to designing grinding circuits.
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