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It is a wellknown fact that the value of the Bond work index (wi) for a given ore varies along with the grinding size. In this study, a variability bysis is carried out with the Bond standard grindability tests on different critical metal ores (W, Ta), ranging from coarse grinding (rod mills) to fine grinding (ball mills). The relationship between wi and grinding size did not show a clear ...
• WiBM The Bond ball mill work index, in metric units. • WiRM The Bond rod mill work index, in metric units. • WiC The Bond impact crushing work index, in metric units. • Density The coarse particle density measured in either the Bond impact crushing work index test or the drop weight test, t/m³.
The Bond ball mill work index test is thought to be additive because of its units of energy; nevertheless, experimental blending results show a nonadditive behavior. The SPI(R) value is known not to be an additive parameter, however errors introduced by block kriging are not thought to be significant .
The charge is milled with the standard Bond ball mill for a set time. A particle size analysis is performed on the feed and ground product, and a modified work index is calculated using a proprietary model. The Mod Bond results must be calibrated against sufficient standard Bond ball mill work indices, typically 10% of the total.
The ball mill grindability test is used for describing ore hardness and it is so widespread that the Bond Work Index generated from the test is often referred to as an ore characteristic. The ore resistance to grinding and energy consumption can be expressed using the work index and Bond's Third Theory.
A Bond Ball Mill Work Index test is a standard test for determining the ball mill work index of a sample of ore. It was developed by Fred Bond in 1952 and modified in 1961 (JKMRC CO., 2006).
The commonly used grindability tests included in the database are the Bond work indices for ball milling, rod milling and crushing; the drop weight test results A, b, A×b, DWi, Mia, Mic, Mih and ...
C) for coarse rocks (7550 mm), a rod mill work index (Wi RM) for intermediate sized particles (253 mm), and a ball mill work index (Wi BM) for small particles (<3 mm) (Ammtec, 2000). Laboratory testwork is required to determine these Work Indices, and each test requires carefully collected samples of rock that is representative of future mill ...
This is because work index frequently changes as a function of the product size in comminution. If target grind size during a project is changed, or if the test is run at the wrong product size, then it is necessarily to provide a correction. The goal of this work is to create an equation to adjust a Bond ball mill work index from one P 80 basis
This was displayed by a reduction in Bond ball mill work index (BBMWI) of the ore from to kWh/t after calcination. ... The ball mill had 12 grinding balls (each grinding ball had mm ...
Conclusions. The power model and linear model both will give reasonable P80 estimates given the P100 of a Bond ball mill work index test product. The power model might be marginally more robust ...
The ball mill grindability test is used for describing ore hardness and it is so widespread that the Bond Work Index generated from the test is often referred to as an ore characteristic. The ore resistance to grinding and energy consumption can be expressed using the work index and Bond's Third Theory.
The Bond work index, W i, is defined in a Bond ball mill on the samples of standard size − + 0 mm. In practice, it is possible to find materials of nonstandard size that are finer than mm.. In this work, a procedure for the calculation of the Bond work index is suggested for cases when the Bond grindability test is conducted on samples of nonstandard size.
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.
Many researchers have tried to find alternative methods for determining this Index to reduce labor costs, sample weight, or to get one without standard equipment. This paper was carried out with the purpose of reviewing, classifying and testing the existing methods for determination the Bond Ball Mill Index.
The FC Bond Work Index Test Ball Mill was designed by F. C. Bond for use in determining the Bond Index, a measure of grindability and power required for grinding applications. The FC Bond Mills are used in laboratories throughout the world. A copy of Fred C. Bond's Method of Crushing and Grinding for determination of the Bond Index is included with each mill. This mill can be used to calculate ...
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expected from their Bond ball milling work indices. In fact, the average ratio of DWi to Bond ball mill work index was at the 90th percentile of a much larger database. This result indicates that the SAG milling power requirements for these ores is likely to be much greater than what would be expected from the Bond ball mill work index.
The Bond work index most commonly referred to is the BBM work index. This value is obtained in a 12" 12" laboratory mill running at 70 rpm, with rounded inner edges and without lifters. The grinding charge is comprised of a distribution of steel balls with several diameters. Table1shows the original Bond proposal [13], while the last Bond
The results of the "raw" Bond ball mill work index values for dacite, basalt, and copper ore samples on coarse and fine samples are shown in Table 1. The raw work index is computed using Eq. (10) for the laboratory test results for both "valid" (F 100 = mm) and "invalid" (F 100 ≠ mm) feed to the test.
MenéndezAguado et al. examined the possibility of determining the work index in a Denver laboratory batch ball mill with the same inner diameter as the Bond ball standard mill. The research was performed on the size class of − mm using samples of gypsum, celestite, feldspar, clinker, limestone, fluorite, and copper slag.
Work index is the relation between the SEC and the amount of breakage in an ore. The most common form of this relationship is given as Equation 1, and is often referred to as "Bond's equation" or "Bond's law." E=10× √P − √ F 80 80 ) ( 1 ) Where: E is the specific energy consumption in kWh/t
The grinding jar of the Bond Index Ball Mill measures 12″ x 12″ and has wellrounded corners. ... At least 15 to 20 kg sample material is required to simulate a closed grinding circuit in a ball or rod mill. The Rod Mill Work Index (RWI) is used for particle size determination in a size range from 25 mm down to mm whereas Ball Mill Work ...
Abstract The Frederick C. Bond has several grinding indices (ball, rod, abrasion), one of which has been a significant guide for ball mills. The Bond ball mill work index is an expression of the material's resistance to ground and a measure of the grinding efficiency.
The work index Wi was defined by F. Bond as the specific energy (kWh/ton) required to reduce a particulate material from infinite grain size to 100 microns. ... The energy consumed by the ball ...
grams per revolution (Gbp) is the ball mill grindability. The ball mill work index, Wi (kWh/short ton) is calculated from the following equation (Bond 1961):1 The mill should be cleaned by either blowing air into it or wiping the interior with a cloth and or brush. The FC Bond ball mill is now ready for the next sample.
W is the work index measured in a laboratory ball mill (kilowatthours per metric or short ton) P 80 is the mill circuit product size in micrometers; F 80 is the mill circuit feed size in micrometers. Buhrstone mill. Another type of fine grinder commonly used is the French buhrstone mill, which is similar to oldfashioned flour mills.
It provides the Bond Ball Mill Work Index which expresses the resistance of material to ball milling. This happens after 710 grinding cycles, which shows that the procedure is a lengthy and ...
Semiautogenous plus ball mill has been the "work horse" of mills. SAG vs Ball Mill Advantages . AG SAG Mill Grinding Compared Which is Best ... Rod mill grindability tests for Work Index are run at 10 or 14 mesh, and ball mill Work Index tests are run at the desired grind if finer than 28 mesh. All the data obtained is evaluated and ...
The work index can either be measured in the laboratory (the Bond ball mill work index determination is a common example) or it can be calculated from the operating performance of a milling ...
This Table of Ball Mill Bond Work Index of Minerals is a summary as tested on 'around the world sample'. You can find the SG of each mineral samples on the other table.
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