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The unique feature of this method is that the mill power draw can be predicted for a mixture of ball sizes, different lifter geometry and lifter spacing, which is absent in other methods (Data et ...
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the application of ball mill power from fine (minus P80 product size) to coarse material, ... for a new circuit was provided by Bond (1958). B = (F80/K)0.5 x [(WI x SG)/(Cs x D0.5)]1/3 (3) ... the calculation method of the mill energy specific cumulative grinding rates is shown by the following example. Using plant
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Mill power Usually, plant operators use mill power readings as an indicator of ball filling degree and, often, try to keep it at the maximum level. It is well known that the mill absorbed power depends on operating parameters other than ball level, such as pulp density and liner configuration. Figure 2 shows that there is no linear relation between
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The Bond ball mill work index test has been used for ore hardness characterization for more than 80 years. Nevertheless, the test suffers from significant disadvantages when compared with other characterization methods. It is expensive, labour …
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There is a mathematical solution to this problem – the Bond formula. It uses to help determine the grinding media optimal size must be loaded into the ball mill for proper operation ensure. The calculation formula is below: B – the grinding balls diameter, mm; A – the correction factor (for grinding balls A = 20,17; for cilpence A = 18,15);
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2.2. 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 set to 70 RPM (1.667 Hertz) corresponding to 85% of the critical frequency. The mill power is P = 16.2 Watts,
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Ball mill simulation. Separator simulation. DEM simulation. ... but Users need a certain experience to implement results of these calculators . Sizing equipments and mill's optimization are the job of material suppliers and experienced engineering offices. ... 3 ch. mill (central part) Bond power (2 chambers) Bond power (3 chambers) H & F power ...
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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 ton/h), zthe ball-mill dimensions (D …
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Comminution is the most power-demanding stage, using around 50% of the total consumption. In this context, optimisation in comminution processes is one of the biggest ... The calculation and validation of parameters were carried out in comparison with tests ... Bond Ball Mill Work Index C i: Crushing parameter
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power draft to mill size. The first group can be repre-sented by the Bond F.C. (1960) test method. This method is widely used both for evaluating the grindability of a material and for determining the power required to drive the mill. However, it uses data from laboratory tests while many empirical correction factors were proposed for the
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Starting from the dimensions of the Bond ball mill a modified test method was developed where small size samples of approximately 220 g were pre-crushed and ground in a down-scaled one-stage grindability test. Down-scaling was done by keeping similar impact effects between the mills. Mill speed and grinding time were
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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 …
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Bond's method is widely used for predicting the energy requirement of crushers, rod and ball mills, while a number of other methodologies have been proposed for AG/SAG mills.
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SAGMILLING .:. Articles. Mining projects are applying the age-old notion of "check your work" against comminution circuit design, mill power requirement estimates and mill throughput estimates. The best way to test the results of one comminution modelling system is to replicate the calculation in a different modelling system.
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However, upon close inspection of Bond's original paper published in 1949, Bond stated that the net energy input to the laboratory scale ball mill was 93 J/rev which is comparable to the digital ...
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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 …
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The Bond's method was used in sizing the laboratory ball mill. This method is based on two power calculation approaches used in ball and rod mill design processes due to its simplicity and workability. The first approach, which is specific power calculation, determines the power required to grind an ore from a
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Power reduction in ball mills using small media at the same charge volume of 25 mm balls. ... (Bond, 1961). A second method is to calculate the ... the use of a corrected make up size formula by Azzaroni (1981) and breakage function were …
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Consequentially, DEM is an accurate numerical calculation method that can predict the power consumption of ball mills more accurately than other methods could. • The torque and power of a ball mill usually increase with an increase in mill speed when no lifter exists in the mill (N l = 0 or H L = 0 mm). Usually, the slope is extremely small.
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of the Bond ball mill grindability test. For all model based methods, a reliable method to calculate mill power draw for a given mill is required for the calculation of power draw. Morrell (1996) proposed a mathematical model for autogenous, semi-autogenous and ball mills which is based on the motion of grinding charge inside the mill.
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power draw, is used for the ball-mill scale up. Comparisons with the Bond procedure showed a good agreement for the prediction of the ball-mill dimensions, due to the
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Mill sizing method. The mill sizing page: Please find below two calculators for sizing mills using the Bond and Rowland methods: Ball mill sizing: Calculator for ball mill (s) in a single stage circuit. Rod ball mill sizing: Calculator for rod mill (s) as first stage of the circuit and ball mill (s) as second stage of the. circuit.
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The Bond equation is used to calculate ball mill specific energy from T 80to the final product P 80size. The total circuit specific energy is the sum of the SAG mill and ball mill specific energies. W SAG= R (Ms+16000)/(Ms.447.3) (4) W T= K a . K b . W SAG . [10. BWi. (T 80 -0.5-1700-0.5). EF5] + W BM . K BM(5) Where: W
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The work performed included analysis of operating performance data from 49 mills and included extensive determinations of the Bond Abrasion Index for different ore types. For an improved understanding, the wear rate constant is directly related to the grinding media consumption rate expressed in grams of steel per kWh drawn by the mill, using ...
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According to Bond's ball mill equation (Bond, 1961), a coarse correction factor needs to be applied, and efficiency losses over 25% can occur in a ball mill. The savings on SAG mill power are offset by ball milling efficiency losses so the result of making a coarse SAG product is negative because the ball mill power is increased and the ...
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stage ball mills, rod mills or AG/SAG mills when calculating power according to the Bond Third Theory method. Rod mill and AG/SAG mill products are similar and tend to be not as steep as a 0.5 slope when plotted on log-log paper. This is because …
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Rowling are used to calculate the mill power draw. The Morgärdshammar equation and the IMM equations are shown for comparison. The method of use is similar to the AM section 3.3 Ball Mill Design The ball mill designs also follow the Bond/Rowlings method with comparison with other methods. Again the method of use is the same
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A POWER BASED APPROACH FOR THE SELECTION AND COMPARISON OF BALL MILL LINERS by Olav Mejia Alarcon B.A., Univ. Nac. Mayor de San Marcos, 1992 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF
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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 cir-cuits with a P80 finer than approximately 70 µm without making qualifications. 3. Calculate the circuit ...
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SUMMARY OF ORE CHARACTERIZATION TEST WORK METHODS AND POWER BASED MODELS When Bond first developed his comminution law, crushers, rod mills and ball mills were common equipment in the flowsheet. These tests were developed for the basis of scale-up of staged crush, rod and ball mill circuits (Bond, 1952).
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