The ball mill work index laboratory test is conducted by grinding an ore sample prepared to 100% passing 3.36 mm (6 mesh) to product size in the range of 45-150 m (325-100 mesh), thus determining the ball mill work index (Wi B or BWi). The work index calculations across a narrow size range are conducted using the appropriate laboratory work index determination for the material size of interest, or by chaining individual
May 01, 2021 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 grinding power. Although considered an industry standard, Bond did not fully define that procedure, and therefore significant discrepancies in test results can sometimes be obtained due to some undefined steps in the method.
1. Calculate the Actual Operating Bond Work Index of the grinding circuit. Estimate the F80 and P80. Calculate the work or specific energy input from the size reduction equipment power and circuit tonnage (equation 1). Auxiliary equipment power is excluded. P W (1) T
Oct 24, 2018 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 ...
Mill diameter Mineral density Work Index. Bond estimated the amount of wear in terms of kilograms per kWh based on the abrasion index, A, i.e., Wet Ball Mill kg kWh 0.16(A i-0.015) 0.33 Dry Ball Mill kg / kWh 0.023A i 0.5 Replacement Ball Size
rod mill work index has not been de ned as yet. The ball mill work index is con rmed at 16 kWh/t. The operating work index, though, is in the range of 21 kWh/t to 25 kWh/t showing high inef ciency. This raises the point that, in some cases, the Bond EF4 oversize factor calculation is not suf cient to compensate
2, the operating work index (Wio) of an existing grinding circuit can be calculated, given known mill power draw, throughput, feed and product size distributions. kWh/t Power applied per ton of feed to the grinding unit Wi The standard Bond work index of the ore P 80 The 80% cumulative passing size
Ball Mill Batch Process The mill dimensions, (D L), are 0.204 0.158 m and it is loaded with 6.5 kg steel balls between 25 and 32 mm in diameter. The mill rotates on rolls and its frequency is ... A New Approach to the Calculation of Work Index and the Potential Energy of a Particulate Material ...
The Bond work index, W i , is defined in a Bond ball mill on the samples of standard size 3.327 0 mm. In practice, it is possible to find materials of non-standard size that are finer than 3.327 mm. In this work, a procedure for the calculation of
work indices for the AG/SAG mill and ball mill can be re-organised as 7 and 8, where BWio and AWio are the corrected operating work indices and WAG/SAG, WBM are the respective power draw of AG/SAG and ball mills. Note that the ball mill operating work index is applied only on
Calculation of energy required for grinding in a ball,A bond ball mill work index is then performed on the mill product for the design of sagball mill circuits this is important because it was found that there was a 115 kwht higher ball mill work index if the 335 mm ball mill test feed size is moret.get price
The Bond Ball Mill Work Index (BBWi) test is carried out in a standardised ball mill with a pre-defined media and ore charge. The Work Index calculated from the testing can be used in the design and analysis of ball mill circuits. The test requires a minimum of 10kg of sample that
Keywords work index, Bond method, kinetic grinding test, grindability, ball mill Introduction The standard Bond (1952 1961) method is widely used in the course of design, selection, scale up, energy calculation and performance evaluation of grinding circuits in mineral processing industry.
For overflow ball mills, the charge should not exceed 45% of the mill volume . For grate discharge mills, the charge should occupy about 50% of the mill volume . Bond developed a relationship that can be used to determine the percent charge by volume as a function of the vertical height above the
work index approximate value is exactly the same as in the first two grinding cycles of. the standard Bond test and consists of the program. Prepare a sample, the same as for the standard Bond ...
Dec 18, 2013 In ball milling, the Bond ball mill work index can be used to determine specific energy at a range of feed and product sizes. The Bond top size ball formula can be used to estimate the media size required. No such standard formulas exist in fine grinding. Energy and media parameters must instead be determined in the laboratory for every new ...
Technical Information. The SMC Test is the most widely-used comminution test in the world for AG SAG Mills, HPGRs and Crushers. The SMC Test was developed to provide a range of useful comminution parameters through highly controlled breakage of rock samples. Drill
Correction of Bond Ball Mill Work Index Test for Closing Mesh Sizes It is commonly known that one must run the Bond ball mill work index test such you pick a closing mesh to give a P80 close to desired grind size.
The aim of this study was to develop a new method for assessing the Bond work index in a ball mill (BBWI), which is based on a first order kinetics present in the Bond ball mill for grinding mineral raw materials (Austin et al., 1981 Ahmadi and Shahsavari, 2009). Theoretical basis of quick procedure
Closed circuit 8 dia. ball mill to P80 um The ore Test Work Index Circuit Operating Work Index 9 The Standard Bond Circuit Coarse Ore Bins Fine Ore Bins Screen Crushing Screen Classification Rod Mill Ball Mill THIS IS THE REFERENCE BASIS FOR ALL WORK INDEX EFFICIENCY DETERMINATIONS 10. 2/20/2014 6 Example SAG-Ball Mill Circuit WI ...
Ball mill work index test was widely used in the 1960s and still remains in use today (Gharehgheshlagh 2016). The ball mill work index of the feed samples was determined according to the standard ...
The work index of a particular material is determined in the laboratory by conducting the standard Bond grindability test. Bond developed separate tests for the rod mill and the ball mill. The simplified test method described in this paper is an alternative procedure to the ball mill grindability test.
Jul 15, 2021 Now, Click on Ball Mill Sizing under Materials and Metallurgical. Now, Click on Specific Power of Mill under Ball Mill Sizing The screenshot below displays the page or activity to enter your values, to get the answer for the specific power of mill according to the respective parameters which is the Work Index of Ground Material (w i), 80% Product Size (P 80) and 80% Feed Size (F 80).
work index RWI for finer particles ball milling work index BWI (Table). These indexes are readily obtained using the special-purpose laboratory equipment (Fig. 1). Finding the total specific energy consumption in the wet autogenous mill central discharge ball mill circuit (WAM CDBM) In
Dec 07, 2018 The goal of this work is to create an equation to adjust a Bond ball mill work index from one P 80 basis to another. The proposed model consists of two components, the variable coefficient that is determined from a specific work index determination and a fixed
In this regard calculation of work index of limestone made by standard Bond grindability test. Ball mill was employed to conduct the grinding test of seven different samples. Among all seven samples collected from the different faces of quarry, Bond work index of limestone Face4A results less than 20kwh/t, remaining 6 samples are marked as hard -
The ball mill oversize feed factor (EF 4 BM) is always calculated with the ball mill work index. The optimal feed size for the EF 4 BM is always calculated using the rod mill work index. The Easag RM value in the circuit configuration is used to specify which work index to use for a particular size
Dec 12, 2016 Ball Mill Power Calculation Example 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 inch (6350 microns).
The ball mill oversize feed factor (EF 4 BM) is always calculated with the rod mill work index for the optimum feed size and the ball mill work index for EF 4 BM. The model assumes that the calculated value of E ssbm the specified contingency is greater than the sum of E sag E peb otherwise E bm will be negative.
How to Calculate and Solve for Specific Power of Mill Ball Mill Sizing The image above represents the specific power of mill. To compute for specific power of mill, three essential parameters are needed and these parameters are Work Index of Ground Material (w i ), 80% Product Size (P 80 ) and 80% Feed Size (F 80 ).
Testwork Bond Ball Mill Work Index. 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 locked-cycle test where ground product is removed from test cycles and replaced by fresh feed. The test much achieve a steady-state before completion.
Ball mill work index adjustment. The Bond ball mill work index test requires the operator to select an appropriate screen size to close the test. The procedure states that the closing screen size should be such that the product size of the test is the same as the expected product size of the operating plant.
cycle test akin to the Bond Ball mill work . index determination. The first cycle starts with minus 6 mesh ore removed since it is believed that the fines content can fill most of the voids allowing little room for rock breakage and piston movement. Without adequate piston movement there is little measurable energy used
In this scientific study, the objective is to determine the Bond work index of a given ore. A given ore was prepared by stage crushing and grinding, and underwent feed size analysis. After which, the ore was grinded in a ball mill until a 250% circulating load was achieved.
However, in this situation the ball mill has to supply this energy and it has a different (higher) work index than the crusher (ie the ball mill is less energy efficient than a crusher and has to input more energy to do the same amount of size reduction). Hence from equation 7, to crush to the ball mill circuit feed size (x. 2
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