where: WiC is the Bond crushing work index, unitless P80 is the SAG hydrocyclone overflow 80% passing size, µm F80 is the milling circuit feed 80% passing size, µm, WiRM is the Bond rod mill work index, unitless WiBM is the Bond ball mill work index, unitless EF4 and EF5 are the Rowland efficiency factors for oversized feed and fine grinding.
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How to Measure Grinding Efficiency. The first two Grinding Efficiency Measurement examples are given to show how to calculate Wio and Wioc for single stage ball mills. Figure 1. The first example is a comparison of two parallel mills from a daily operating report. Mill size x (′ x 20′ with a ID of 16′).
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µm. Note that—in order for no correction factor for ball mill product fineness to apply—the ball mill circuit P80 should be no less than approximately 70 µm (Bond, 1962). This Bond Efficiency determination should not be applied to circuits with a P80 finer than approximately 70 µm without making qualifications. 3.
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Since for the ball mill design we are using 80% passing, the required value of C2 for the ball mill will be equal C3 is the correction factor for mill diameter and is given as; 𝐶𝐶3 = 𝐷𝐷 (3) However, it is important to note that C3 = vessel used in producing the ball mill was got from a
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Over the years, alternative procedures to the Bond grindability test have been proposed aiming to avoid the need for the standard mill or to reduce and simplify the grinding procedure. Some of them use the standard mill, while others are based on a nonstandard mill or computation techniques.
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The reason for this variation in ball mill work index is because the ore at Mt. Milligan has an intrinsic exponent of in the 100 µm to 200 µm size range, not the exponent empirically measured by F. Bond. The work index increase between 100 µm and 76 µm is due to a porphyritic grain size that causes a spike in energy
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See other industries within the Manufacturing sector: Aerospace Product and Parts Manufacturing, Agriculture, Construction, and Mining Machinery Manufacturing, Alumina and Aluminum Production and Processing, Animal Food Manufacturing, Animal Slaughtering and Processing, Apparel Accessories and Other Apparel Manufacturing, Apparel Knitting Mills, Architectural and Structural Metals ...
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Standard Bond tests showed a reduction in the Bond ball mill work index (wi) of the mineral sample used in this study when using Relo grinding media. ... The Effect of MakeUp Ball Size Regime on Grinding Efficiency of FullScale Ball Mill. In Proceedings of the XVII Balkan Mineral Processing Congress, Antaliya, Turkey, 13 November 2017 ...
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Bond's Table II [BON 54] gives a correction coefficient for the mill's shaft energy according to the latter's type and φ.. 2) Milled output with a size that is less than 70 μm:. The reference value W i must be multiplied by an enhancing coefficient [BON 54, p. 384].. 3) Wet grinding and dry grinding: Dry grinding requires more energy than wet grinding.
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grams per revolution (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 brush. The FC Bond ball mill is now ready for the next sample.
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Cleaning and Storing of Ball Mill Charge after the Bond Work Index Procedure is done: Add about 500 g of silica sand into the mill containing the ball charge. Seal the mill. Rotate for 20 revolutions to clean. Empty the mill charge and sand into the ball try once grinding is complete. Clean out the mill using a brush. Put the lid on the mill.
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ball milling using the Bond test scaleup method. Wi STD Wi Efficiency Ratio = Wi oACT The actual plant circuit can deploy any type of size reduction equipment. Thus, this tool can be used by operators and designers to benchmark the energy efficiency of any size reduction circuit, over the applicable size reduction range,
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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 ...
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Based on experience acquired over the years and the investigative work conducted by Bond, it was established that the optimum circulating load for a closed ball mill cyclone circuit is around 250%. This value is used as guideline for the design of new circuits as well as to assess the performance of existing circuits.
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Ball Mill Power/Design Calculation Example #2 In Example it was determined that a 1400 HP wet grinding ball mill was required to grind 100 TPH of material with a Bond Work Index of 15 ( guess what mineral type it is ) from 80% passing ¼ inch to 80% passing 100 mesh in closed circuit.
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hpp Company Profile | Falkensee, Brandenburg, Germany | Competitors, Financials Contacts Dun Bradstreet
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The Bond work index, W i, is defined in a Bond ball mill on the samples of standard size ... Addition of pebbles to a ballmill to improve grinding efficiency. Minerals Engineering, Volumes 103104, 2017, pp. 7277. Show abstract. Ballmills are used widely for secondary grinding.
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The Bond test relies on empirical fitting parameters determined by Bond and expressed as exponents on the closing screen size () and the net grams per revolution (). These parameters were fitted to equate the results from the standard Bond Ball test to a standard pilot plant utilising a m diameter ball mill (Bond, 1961).
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Figures in this table are generally slightly low compared to some reported plant data or other manufacturers' estimates, and are based on an empirical formula initially proposed by Bond (1961) designed to cover a wide range of mill dimensions, and the normal operating range of mill load (Vp = .35 to .50) and speed (Cs = .50 to .80).
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Mill power draw prediction can be carried out using Morrell's power model for tumbling mills. Bond methodThe established technique for determining power requirements for ball mills is the Bond method (Bond, 1961). This method also involves the application of some 'efficiency factors' as described by Rowland (1975).
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You can use the lab data from a standard bond ball mill test to calculate this alternative index. Helena Russell. 8 years ago. ... give a direct measure of grinding efficiency. The Bond Equation and the equations for the associated efficiency factors can be used by plant supervisory and technical personnel and can also be used in computer ...
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The mill was still producing scats, though less than at 78% of critical speed. The original milling circuit design for the Kroondal platinum concentrator was based on the following: > Primary milling discharge of 30% passing 75 μ m. > Secondary milling discharge of 6772% μ m, with natural fines grits.
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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 ...
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Mike Daniel (2008) again: 'The energy efficiency of most comminution devices, in particular that of ball mills, is generally very poor. 'Innovative research in High Pressure Grinding Rolls (HPGR) technology is being pursued nowadays as a means of improving overall comminution energy efficiency.'
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Wang C (2013) Comparison of HPGR—ball mill and HPGR—stirred mill circuits to the existing AG/SAG mill—ball mill circuits. ... Abouzeid AZ (2002) The energy efficiency of ball milling in comminution. Int J Miner Process 67:161185. ... McIvor R (2016) The GMSG guideline for determine the bond efficiency of industrial grinding circuits ...
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Since for the ball mill design we are using 80% passing, the required value of C2 for the ball mill will be equal C3 is the correction factor for mill diameter and is given as; 𝐶𝐶3 = 𝐷𝐷 (3) However, it is important to note that C3 = vessel used in producing the ball mill was got from a
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and the Bond Ball Mill Test Work Index (WiBM; GMG, 2016a), and the Morrell equations and their application (see Annex B). A worked example is provided in Annex C. 5. SCOPE ... mining the Bond Efficiency of industrial grinding circuits. Montreal, QC: Global Mining Guidelines Group. • Global Mining Guidelines Group (GMG) (2016b). Meth
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The ball impact energy on grain is proportional to the ball diameter to the third power: 3 E K 1 d b. (3) The coefficient of proportionality K 1 directly depends on the mill diameter, ball mill loading, milling rate and the type of grinding (wet/dry). None of the characteristics of the material being ground have any influence on K 1.
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For typical circuits that involve AG/SAG, HPGR or ball milling, the generation of 75 µm material (denoted as SSE75) is a suitable marker size with which to benchmark performance because it contains 80% of the surface area generation 1 and energy is proportional to surface area generation 2.
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Meeting of Bond Efficiency Guideline Working Group of the Global Mining and Standards Group Salt lake City, 2014 Based on Presentation to the 2008 Meeting of SME, by ... Example SAGBall Mill Circuit WI Efficiency Calculation • SAGball circuit F80 = 165,000 um P80 = 125 um W = kWh/t Wlo = / [( 10 / SQRT 125) (10 / SQRT 165,000 ...
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As such Bond ball mill work index alone is not an effective basis to estimate the comminution energy requirements for many of Newmonts operations. Figure 1 Newmont sites on the Bond intensity energy curve, comparing the BWi The position of the sites on the Bond operating work index (OWi) energy curve is presented in Figure 2. What is
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Typical Mill Circuit Represented by the Bond Ball Mill Test. The procedure for the work index test bases the BW i value on the calculation of new fines generated in the test. This means that the fraction of fines in the feed should not influence the test result significantly, if at all.
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b=70%. b= . b=0%. 2. E. It should be emphasised that this increase is with respect to ~95% passing size material and not 80%. passing size (or P80) as defined in Bond's method. screen sizes ...
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DMBDiagnostics Company Profile | Falkensee, Brandenburg, Germany | Competitors, Financials Contacts Dun Bradstreet
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A material supplier from Belgium would like to produce limestone powder for his custome...
India is rich in various mineral resources and it is an important mineral processing market
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