Anyone wondering how Bond ball mill work index compares versus SPI or JK A*b? Well, M. Doll says, several comparisons have been published, such as at CMP 2011 and Procemin 2009 and in …
The laboratory procedure for running a Bond ball mill work index test requires that the operator choose a closing screen sieve size. The instruction is to choose a sieve size that results in the ...
The Work Index is used when determining the size of the mill and grinding power required to produce the required ore throughput in a ball mill. 2. Procedure. 2.1. Bond Ball Mill …
The Bond work index (BWI) is a well-known method used when selecting comminution equipment, to evaluate the grinding efficiency and to calculate the required …
It is a well-known 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 …
For the ball mill grindability test, the work index is calculated from the following revised equation (in short tons): where: Pi = sieve size tested (microns) Gpb = ball mill grind ability Wi, P & F have the same meanings as in the top equation. Equipment required: Laboratory ball mill, 34.02 cm x 34.02 cm with following ball charge: Agitator ...
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 Source 5 Source 6 Source 6 KWh/t Source 6; Avg Bond Work Index: kWh/t: kWh/t: kWh/sh.t: kWh/t: kWh/t: kWh/t: kWh/t: …
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 …
The test determines the Bond Impact Work Index which is used with Bond's Third Theory of Comminution to calculate net power requirements when sizing crushers*. It is also used to determine the required open-side settings (jaw crushers and gyratory crushers) or closed-side settings (cone crushers) for a given product size.P80 = 25400 x …
A) Total Apparent Volumetric Charge Filling – including balls and excess slurry on top of the ball charge, plus the interstitial voids in between the balls – expressed as a percentage of the net internal mill volume (inside liners). B) Overflow Discharge Mills operating at low ball fillings – slurry may accumulate on top of the ball charge; causing, …
This paper proposes a new method to estimate the Bond Ball mill work index result to decrease experimental time. Four types of ore (limestone, fluorite, chalcopyrite, …
The P 80 of a ball mill work index test can be estimated if the P 100 is know based on this equation: Estimate grams per revolution when only P100 is known. NI43-101 reports often provide P 100 and the work …
It is a well-known 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).
Design engineers generally use Bond Work Index and Bond energy equation to estimate specific energy requirements for ball milling operations. Morrell has proposed different equations for the Work Index and specific energy, which are claimed to have a wider range of application. In this paper an attempt has been made to provide a …
Analysis of Bond Work Index test results for crushing, rod milling and ball milling will indicate uniformity or otherwise of breakage characteristics in different size ranges. Very often one is much higher (or lower) than the others and such variations can govern the power distribution between primary and secondary stages of grinding.
The most impacting result of this work is the different results when matching work index values and grindability index values from the od mill's size range to the ball mill's size range, showing ...
The Bond ball mill grindability test is one of the most common metrics used in the mining industry for ore hardness measurements. The test is an important part of the Bond work …
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 Bond Work Index (Wi) is a common technique for the estimation of hardness and energy requirement for comminution using ball mills. ... fitting in all cases to a quadratic curve with a very ...
This paper describes a methodology for providing an estimation of the Bond ball mill work index for a sample of non-standard size (F 100 ≠ −3.35 mm) when all the …
The basic work index equation is: W = 10 Wi/√P – 10 Wi/√F(1) where W is the work input required in kilowatt hours per short ton to grind from 80% passing F microns to 80% passing P microns, and Wi is the work index, or the grinding resistance parameter. It represents the energy input …
The work index values apply to ball mills grinding wet in closed circuit. For dry grinding in closed circuit the work input calculated by Bond's basic Third Theory equation should be mul tiplied by 1.30 (see example …
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
21 CONCLUSIONS Continued In the present work, equations were also derived, giving: zthe ball-mill power drawP as a function of its dimensions: internal mill diameter D and length L, zthe ball-mill power drawP as a function of the feed D f (mm) and the product size d (mm), the Bond work index w i (kWh/short ton) and the mill throughput T (short …
Analysis of Bond Work Index test results for crushing, rod milling and ball milling will indicate uniformity or otherwise of breakage characteristics in different size ranges. Very often one is much higher (or …
2.2.1 Ultrafine Ball Mill Ultrafine ball mill equipped with Nob to adjust the rpm and time required to grind the material. 50ml of bowl/pan is used as a container for the material to be grinded. Mechanical clamp are provided to hold the bowl so that the grinding material is intact so that spillage of material can be constrained.
should be noted that in the Bond standard approach, the ball milling work index has the largest influence. For a P 80 of 100 µm, the ball milling work index accounts for approximately 70% of the weighting in the Bond standard calculation (GMG, 2015), with the rod mill taking 25% and the crushing work index 5%.
mill. As such, primary ball mills should be designed with the rod mill work index, and single-stage ball mills should be with both the rod mill and ball mill indices. This is because it is common to observe a difference (sometimes significant) between the rod mill and ball mill index values for a given ore type (McKen, Verret, & Williams, 2006). On
Experimental validations from locked-cycle tests to insights gained from DEM analysis provide a potential application of the RELO media in ball mill application over conventional spherical media shapes. Preliminary lab tests indicate a potential 10% reduction in the Bond Work Index for an equivalent ball mill operating with a spherical media ...
The objective of this study is to investigate the effect of ball size on grinding kinetics in a pilot scale ball mill. Six different ball media gradings were tested. Comparative tests were conducted in batch ball mill having 1.2m diameter and 0.6m length at constant operating condition of mill such as media mass, mill speed and input specific ...
For P80s finer than 75 μm, the Levin test, a modified Bond ball mill work index test, may be used to predict grinding performance. ... has yet been found for the fine grinding regime. Instead, the work-to-P80 curve is determined in the laboratory for each case. The energy use usually fits an equation of the form
The curve can be determined easily from the grinding result of an arbitrary ball mill. It enables the prediction of the effects of many variables on the fineness of the ground material.
When F is the size in microns which 30 per cent of the new ball mill feed passes, P is the microns which 80 per cent of the last cycle sieve undersize product passes, and P1 is the opening in microns of the sieve size tested, then ball mill work index Wi is calculated from the following revised (1960) equation:
