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Notes on Ball Mill Design Energy Required for Comminution Feed material is assumed coarse hard rock Feed Size and Product Size are 80 passing mesh sizes micron 5 Bond Work Index 50 kWhshort ton Imperial units150 Feed Size 25000 micron20 Product Size 200 micron03 Ball Vol Fraction 05Ball Depth measured from top of shell to balls
The EDEMET Bond Mill is designed to perform the Bond ball mill work index test to determine the grinding energetic consumption of diverse minerals As this is a standard test its design has been maintained according to the traditional equipment Aditional information about the EDEMET Bond Mill can be found currently in our spanish websites wwwedemetcl
Ball mills usually operate at 65 to 75 of the critical speed The critical speed is calculated as under 5 R r g 2 1 n c 2 213 Work Index Work index is defined as the gross energy required in kilowatthours per ton of feed needed to reduce a very large feed to such a size that 80 of the undersize passes through 100181m screen 5
Later work done by Hukki 1975 attempted to show the validity of each theory within a certain particle size range This study illustrated that Kicks law was applicable in the crushing range above 1 cm in diameter Bonds theory was more suited to the particle size ranges involved in conventional ball and rod mill grinding 5 to 250 mm
Mill Type Tower Mills Engineering Design Number of Mills 6 Calculations Tonnage Rate th 346 Mass Balance Bond Work Index Design kWht 140 Engineering Design SolidsPulp Density 65 Engineering Design Feed Size F80 181m 135 Engineering Design Product Size P80 181m 20 TestworkEngineering Design Mill Ball Charge TBD Engineering Design
Oleg D Neikov in Handbook of NonFerrous Metal Powders 2009 Tumbling Ball Mills Tumbling ball mills or ball mills are most widely used in both wet and dry systems in batch and continuous operations and on a small and large scale Grinding elements in ball mills travel at different velocities Therefore collision force direction and kinetic energy between two or more elements vary
Additionally while techniques like the Bond Work Index and quotscale up factorsquot are useful for coarse grinding they can significantly underestimate grinding needs below 100 microns Similarly Tower Mill laboratory tests typically use much finer media than can be used in full scale operation and testwork is done in quotbatchquot mode
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 has been stagecrushed to 100 passing size of lt335 mm Any screen size below 600181m can be used for the testwork depending on your requirements Bond Rod Mill Grindability Test
The grinding jar for the Bond Index Rod Mill is 12 x 24 in size and has a waveshaped 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 21 mm whereas Ball Mill Work
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 20kwht remaining 6 samples are marked as hard
screened and the index determined from the size analysis curves 25 Work Index Determination The asreceived samples were prepared to all passing 335 mm The 106 181m particles were also removed and analysis was conducted on the 335 mm 106 181m material The tests were performed in a standard Bond ball mill with weight of material
First a Jar Mill grindability test requires a 5 lb 2 kg sample and produces a direct measured specific energy net Hphrt to grind from the design feed size to the required product size The second test a Bond Work Index determination results in a specific energy value
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 openclosed
standard Bond crushing and rod mill work indices abrasion indices and by Dawson for Bond Ball Mill Work Index tests using crushed feed and Standard Autogenous Grinding Design SAGDesign Tests patented by Outokumpu See reference 8 below The comparison of these results gives context to how the various measurements relate to each
The EF5 factor only applies below 75 181m to ball Chat Online bond s work index ball mill inner liners design bond s work index ball mill manufactuering design 187 bond s work index ball mill inner liners design 187 bond crushing and grinding calculations part i and ii Get More sag mill work indexxinhaithickener
The Marcy expression is applicable for mill diameters between 152 to 41meters Using peripheral speed the rotational speed can be determined Bond quantified the rod mill power draw as a function of the Work Index capacity and a series of correction factors PM Wmtesti FT Q FT
The geometry of a mill with conical ends is shown in Figure 86 The total volume inside the mill is given by Vm 4 D2 mL 1 2Lc L L 1 DtDm 3 1 DtDm 816 The density of the charge must account for all of the material in the mill including the media which may be steel balls in a ball mill
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 Bond 1961
In Grinding selecting calculate the correct or optimum ball size that allows for the best and optimumideal or target grind size to be achieved by your ball mill is an important thing for a Mineral Processing Engineer AKA Metallurgist to do Often the ball used in ball mills is oversize just in case Well this safety factor can cost you much in recovery andor mill liner wear and
In Mineral Processing Design and Operations Second Edition 2016 934 Mill Speed During normal operation the mill speed tends to vary with mill chargeAccording to available literature the operating speeds of AG mills are much higher than conventional tumbling mills and are in the range of 8085 of the critical speed
Gates JD Giblett A Dunne R 2012 Prediction of plant ball mill media wear rates from laboratory ball mill test data Comminution 12 Minerals Engineering Wear of grinding media in the