bond work index ball mill design and safety factors
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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 3.10), a question arises as to whether this practice will alter the ball mill work index (BW i) of the material
→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. If you
→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 exponent determined by a calibration procedure.
→WiBM Bond Ball Mill Test Work Index (kWh/t) Wic Bond Impact Crushing Test Work Index (kWh/t) WioACT Actual Operating Bond Work Index determined from measurements on the circuit (kWh/t) ing design inefficiency factors into the reference Bond Stan-dard Circuit, assume 2.44 m diameter overflow mills
→micrometers in size. According to the Bond standard procedure, the work index is determined by simulating a dry grinding in a closed circuit in the Bond ball mill to achieve 250% circulating load (Bond, 1949, 1952, 1961). The test is performed on a raw material approximately weighing 10 kg, which coarseness is 100% -3.327 mm.
→Oct 15, 2015· Bond Work Index (BWI) & Hardgrove Grindability Index (HGI) tests for biomass & coal. • BWI can predict the potential for mill choking of biomass in a tube and ball mill. • HGI is a poor method of predicting grindability of biomass in vertical spindle mills. • Pellets should be composed of pre-densified particles close to the target size. •
→Mill Ball Mill Closed circuit crushing to 16 mm Open circuit 8’ dia. rod mill to 1 mm 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
→Bond Test WI’s (kWh/t): Rod Mill: Ball Mill: 9.5 kWh/t.8 9 kWh/t . Bond Standard Circuit Work Index: Assume the rod mill Work Index of 9.5 applies from the actual rod mill feed sizeof 19,300 mµ (although some of this work might ideally be done by crushers to achieve a rod mill F80 of 16,000 m) to a rod µ
→Standard size ranges and the related Bond work indexes Feed size F 80, μm Product size P 80, μm Work index 100000 10000 crushing CWI 10000 2100 rod milling RWI 2100 100 ball milling BWI Fig. 1. Laboratory equipment used by RIVS for determining the Bond work
→Standard size ranges and the related Bond work indexes Feed size F 80, μm Product size P 80, μm Work index 100000 10000 crushing CWI 10000 2100 rod milling RWI 2100 100 ball milling BWI Fig. 1. Laboratory equipment used by RIVS for determining the Bond work
→The grinding jar for the Bond Index Rod Mill is 12″ x 24″ in size and has a wave-shaped design. 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 2.1 mm whereas Ball Mill Work
→the work index depending on the grind size. In this way, work index values are usually obtained for some specific grind size that characterizes the grinding operation to design or under evaluation. This study was carried out in a standard bond ball mill 305 mm x 305 mm size
→Since for the ball mill design we are using 80% passing, the required value of C2 for the ball mill will be equal to1.20. C3 is the correction factor for mill diameter and is given as; 𝐶𝐶3 = 2.44 𝐷𝐷 0.2 (3) However, it is important to note that C3 =0.914 vessel used in producing the ball mill was got from a
→EF5BM=[ P80+10.3 1.145×P80] ( 3 ) The EF4 formula requires both the rod mill and ball mill work index (rod mill Wi is used to calculate the optimal feed size) and because this is a “single-stage ball mill” calculation, the F80 is actually the rod mill feed size (10,000 µm) from Table 1 and the P80 is the ball mill circuit product. The EF5 factor only applies below 75 µm to ball
→correction factors. Design companies with large data bases have determined correction factors which are not disclosed. The Bond Work Index approach is the standard method of selecting ball mills to grind from about 3 mm to 25 µm provided that correction factors are used if necessary. The power prediction is fairly accurate for devices
→Nov 19, 2004· The equation he developed to estimate the ball mill work index using his laboratory test mill is: (8) W i = 49 P 1 0.23 (Gbp) 0.82 10 1 P − 1 F where W i =Bond laboratory ball work index (kW h/tonne); P 1 =closing screen size in μm; Gbp=net grams of screen undersize per mill revolution; P=80% passing size of the product in μm; F=80% passing
→Figure 9: Correlations to Bond Work Index: (A) Effect of modulus of elasticity of the different studied materials on Bond work index, (B) Effect of compressive strength of the different studied materials on Bond work index, (C) Effect
→ 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, the Total Charge Filling Level to
→Operating Bond index can be calculated by equation (2). ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ − = 80 80 iop F 10 P 10 Q W W (2) Where operating work index (kwh/t) isWiop, mill power draw (kw) isW, Q is mill throughput (t/h) andP80,F80 are respectively mill product and feed size distributions. Operating Bond index is not comparable to laboratory
→Dec 12, 2016· 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
→The Bond work index is a measure of ore resistance to crushing and grinding and is determined using the Bond grindability test. Its value constitutes ore characteristic and is used for industrial
→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 -
→In conjunction with the Bond ball mill work index they can be used to accurately predict the overall specific energy requirements of circuits containing: • AG and SAG mills. • Ball mills • Rod mills These factors are best discussed with your local metallurgical laboratory when you are at the planning stage. However, in the majority of
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