Bond´s work index estimation using nonstandard ball mills
The results showed that using the nonstandard mills (between 20 and 35 cm in diameter), the Bond´s model constants (α=; β=, and γ = ), are unable to predict the Work Index ...
The results showed that using the nonstandard mills (between 20 and 35 cm in diameter), the Bond´s model constants (α=; β=, and γ = ), are unable to predict the Work Index ...
Rod mills generate small amounts of fines, as fine particles typically accumulate in the space between rods without enduring comminution [2]. Effective grinding of this material occurs in the ball mill compartment, generating finer fragmentation. The Bond Rod Mill Work Index (BRMWI) test was only possible for Blend 5 (Table 2) due to excessive
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). This index is widely used in the mineral industry for comparing the resistance of different materials to ball milling, for estimating the energy required ...
A modified equation has been proposed to calculate the Bond Ball Grinding Index (BWI), that considers the ratio of the MSL14K mill net grinding power to the net grinding power of Bond ball mill.
A standard Bond mill (Fig. 1) was designed to perform the work index tests and determine the energy consumption of various s mill has a round internal housing at the corners, has no lifters, and is for dry grinding. The inner diameter and the length are m, and the ball load is % of mill volume (equaling a total weight of kg).
The Bond's standard ball mill is used to determine the work index value of differ ent samples. The Bond work index is defined as the kilowatthours per short ton required to break from infinite size to a product size of 80% passing 100 µm. If the breakage characteristics of a material remain constant over all size ranges, the calcul ated work ...
The Bond Ball Mill is a small universal laboratory mill used in calculating the grindability of ... (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
However, Bond Work Indeces are related to the type of equipment to be used (rod mill, ball mill, SAG uses Drop Ball parameterKwhr/m3, so it is more complex than just specific energy consumption ...
An alternative mill ball charge is proposed that closely approximates Bond's original total ball mass, number of balls and ball surface area. Results of 30 Bond Work index tests of six pure materials (calcite, magnesite, labradorite (feldspar), quartz, andalusite and glass) using closing screen apertures (P 1 ) values of 500, 250, 125, 90 and ...
The Bond ball mill test is used to determine the socalled standard work index, which is defined as the specific energy consumption (in kWh/t) required to reduce a material from a notional ...
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 ...
and the Bond Ball Mill Work Index Test (GMG, 2021). The sampling and surveying guideline (GMG, 2016) pro vides addi tional detail on how to collect the required data and is critical to this analysis.
The ability to simulate the Bond work index test also allows examination of truncated ball mill feed size distributions on the work index. For grinding circuits where the feed to a ball mill is sent directly to the classifier and the cyclone underflow feeds the ball mill (see Figure ), a question arises as to whether this practice will alter the ball mill work index (BW i) of the material ...
A Bond Ball Mill, 12" x 12" of fabricated construction comes with electric motor and gear reducer drive, digital counter, jogging button to provide positioning of drum for loading and unloading, emergency stop button, 44 ½ lb ball charge, stand and receiving pan. Perform Fred C. Bond's grindability tests with this standard BWI test ball mill.
The power predictions for ball mills typically use the following form of the Bond equation: = where E is the energy (kilowatthours per metric or short ton) 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
Similar to a Comparative Work Index, this test is an open circuit dry batch grindability test run in the standard Bond Ball Mill for a set time. It can be used at mesh sizes from 65 to 200 mesh (normally 100 mesh). The test requires calibration against the standard Bond Ball Mill Work Index test to estimate the Work Index.
The Bond Work Index (Wi) is a common technique for the estimation of hardness and energy requirement for comminution using ball mills. However, this technique is timeconsuming (close to 5 hours ...
Based on the standard procedure defined by Bond, the ball mill work index is determined by simulating a closed cycle dry grinding in a laboratory Bond ball mill until a stable circulating load of 250% is established (Bond, 1949, Bond, 1952, Bond, 1961). The ball mill work index is determined by Eq. (10). The recommendation is the ball mill ...
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.
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.
Bond Work Index Ball Mill (BWi) The Bond Ball Mill Work Index (BWi) is used to calculate the power requirements to grind ore to a typical ball mill product. Table 3 shows the BWi for each composite. Table 3 ‐ Bond Ball Mill Work Index Sample ID Closing Screen Size (μm) F80 (μm)
The basic parameters used in ball mill design (power calculations), rod mill or any tumbling mill sizing are; material to be ground, characteristics, Bond Work Index, bulk density, specific density, desired mill tonnage capacity DTPH, operating % solids or pulp density, feed size as F80 and maximum 'chunk size', product size as P80 and maximum and finally the type of circuit open/closed ...
The ball mill work index laboratory test is conducted by grinding an ore sample prepared to passing mm to product size in the range of 45150 µm, thus determining the ball mill w i .
The Bond Ball Mill Grindability Test (Bond, 1952, 1961) gives the Bond Ball Mill Work Index. This Index expresses the resistance of a material to ball milling; the higher the value of the Bond Ball Mill Work Index, the more difficult it is to grind the material using a ball mill. This Index is widely used in the mineral industry for:
Once finished the grinding cycles, a minimum of five, the ball mill Bond's work index w i [kWh/sht] can be calculated using Equation (2). In order to express it in metric tons, the corresponding conversion factor must be used. wi = 100 p 10 P80 p F80 (2) where: w i is the ball mill Bond's work index [kWh/sht];
A Bond Work index mill ball charge and closing screen product size distributions for grinding crystalline grains. Int. J. Miner. Process., 165 (2017), pp. 814, / View PDF View article View in Scopus Google Scholar. Menéndez et al., 2018.
Section snippets Material and experimental Bond tests. Samples of dacite and basalt from Serbia, copper ore from a South American metasedimentary copper mine, and copper porphyry ore from Canada, of different feed sizes, were used to determine the Bond ball mill work index according to the standard standard Bond laboratory mill with "DxL = 305 × 305 mm" balls and rotation ...
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. Source 1. Source 2. Source 3. Source 3. Source 4.
The Bond's BallMill Work Index is a measure of the resistance of the material to grinding in a ball mill. This Index is widely used in the industry for comparing the resistance of different materials to ball milling, for estimating the energy required for grinding and for ball mill scaleup.
However, the ball diameters vary due to wear. Therefore, the total ball number should be adjusted from time to time to ensure a total mass of grams. The grinding jar of the Bond Index Ball Mill measures 12″ x 12″ and has wellrounded corners. Module Rod Mill. Minerals precrushed to < mm and sieved ; Drillcore precrushed to ...
properties of ores include the Bond ball mill work index and the Bond rod mill work index.
. These are empirical indices determined by closed circuit grindability tests developed by
. in the mid 1930's. They require a specific 305mm diameter x 305mm long (inside dimensions)
.
The Bond ball mill work index is one of the most commonly used grindability tests in mining, and is often referred to as the Bond work index. The test is a 'lockedcycle' test where ground product is removed from test cycles and replaced by fresh feed. The test much achieve a steadystate before completion.
The work index equation for a ball mill test was generated by Fred Bond to empirically predict the operating work index of an industrial ball mill (8 ft dia by 8 ft effective grinding length ...
HGI vs Bond Index Test Bond Index HGI Mill Comparison Tube Ball mill Babcock mill (ringball) Target Particle Size Any size below 75µm Particle Size Range < (powder) or pellet size µm Mass constriction Volume 700ml Mass 50g Output kWh/ton HGI Index Suitable materials Any Good quality coals