The smallest ball size typically charged into ball mills and tower mills is ½ inch (12.5 mm), although media diameters as small as 6 mm have been used industrially in Vertimills. In a laboratory study by Nesset et al .,[ 7 ] a GIS mill charged with 5-mm steel shot, and with other operating conditions similarly optimized, achieved high energy ...
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A reasonable working estimate to use in the case of gear-and-pinion drives would be 6-7%, ie the estimated power at pinion would be about 6-7% lower than the gross power draw. …
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The calculation results provide a reference for the improvement of the ball mill foundation. ... Furthermore, it is shown that power draw of ball as well as SAG mills can be predicted within 10% ...
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Ball Mill Motor Power Draw Sizing and Design Formula The following equation is used to determine the power that wet grinding overflow ball mills should draw. For mills larger than 3.3 meters (10 feet) …
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Ball mill power draw predicted from the Denver slide rule, kW 0 200 400 600 Calculated ball-mill power draw from the m odel derived, kW Data compared Line y=x Fig. 2. Comparison of the ball mill power draw from the Denver slide rule and the proposed model. Dashed line corresponds to y=x.
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Prediction of correct sag mill power consumption with a change in ore hardness, solid percent (density) to the sag feed, rpm of sag and PSD has always been very tricky. So far, I have used Austin-Morrell model and Hogg- Fuerstenau power model, but these models seem to work well only under certain boundary conditions.
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1 Calculation of ball mill capacity. The production capacity of the ball mill is determined by the amount of material required to be ground, and it must have a certain margin when designing and selecting. There are many factors affecting the production capacity of the ball mill, in addition to the nature of the material (grain size, hardness, …
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To calculate the operating work index of a circuit, you must measure four things: P: The power draw of the mill. This is usually calculated from the input leads to the motor, then multiplied by ...
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Gross Power Draw and Specific Energy Calculator for Autogenous Grinding (AG), Semi-Autogenous Grinding (SAG) and Ball Mills. Exit Mill Calculator. Shell Sizing Parameters. ... To predict the performance of SAG and ball mills, a variety of calculations can be used. One common calculation is the Bond Work Index, which measures the energy required ...
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Ball mill power draw calculation (1 reply and 1 comment) H. Hamid72. 5 years ago. Hamid72 5 years ago. Hello everybody. We have a ball mill in our plant with 2m …
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KWr = kilowatts per short ton of rods. D = mill diameter indise liners, in feet. Vp = fraction of mill volume rod load (ground out mill).
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The main control on the power draw for a BM is the load of grinding media however adding water to the cyclone underflow can also be short term control of BM power. Higher ball loads will result in finer grind but don't overcharge. If throughput of slurry to BM decreases the mill power draw will increase because balls grinding against balls ...
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The circulating load is a result of the ore hardness, mill power, power efficiency (i.e. size of balls, slurry density, etc), classification efficiency, and product size. The power draw is …
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A control chart of mill power draw should be maintained. If the power draw is too low, additional balls should be added. If the power draw exceeds the upper limit, ball additions should be ceased. Prior to mill shutdowns, the operators should occasionally grind out the mill for a short period of time. This is simply stopping mill feed and ...
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mill is the energy consumption. The power supplied to the mill is used primarily to lift the load (medium and charge). Additional power is required to keep the mill rotating. 8.1.3 Power drawn by ball, semi-autogenous and autogenous mills A simplified picture of the mill load is shown in Figure 8.3 Ad this can be used to establish the essential ...
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is obtainable directly from the batch test or by back calculation from the model for a continuous test. In either case the continuous flow scrubber needs to be selected to achieve
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The fraction of mill volume occupied by rocks, grinding media and slurry in grinding mills are dominant factors influencing AG and SAG mill power draw and grinding rate.
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Bond published Equation 2 for overflow discharge ball mills. Furthermore, to calculate grate discharge mills' power, he proposed the multiplying factor of 1.15. KWb = 4.893D 0.3(3.2-3V p)Cs(1-0.1 2(9-10Cs ... established the following simple equation for predicting the ball mills' power draw: P = 10.38fcD2.5Lρf L(1-fL) (8) 4 Physicochem ...
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In this paper, we concentrate on predictions of power draw. 3. Calculation of torque and powerEvery particle collision with the mill liner produces a torque on the mill. For each timestep these individual torques are summed to give the instantaneous torque on the mill. Only particles in contact with the mill contribute.
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• Effective mill power draw • Ball mill specific grinding rate • Ball mill grinding efficiency The circuit output is defined as the production rate of fines by the circuit. It is calculated from three values: 1. The dry ore feed rate to the circuit (t/h). 2. The % fines in the circuit feed. 3. The % fines in the circuit product.
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Calculating Power Draw when sizing Ball Mills. Im interested to know when sizing a new ball mill, as to why recirculating load has no effect on the power calculation, although it will have effect on volumetric capacity naturally. For instance a mill of 300tph with a 300% recirculating load would have 1200tph going through effectively, but if we reduce the …
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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,...
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bling mills (AG/SAG, rod, and ball mills) involved in reducing the size of the primary crusher product to that of the final product (usually the cyclone overflow of the last stage of grinding prior to flotation/leach-ing). 2. Feed rate to the circuit (dry tonnes/h) 3. Power draw of the comminution equipment (kW)
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Ball mill power draw calculation (1 reply and 1 comment) H. Hamid72. 5 years ago. Hamid72 5 years ago. Hello everybody. We have a ball mill in our plant with 2m diameter and 7 m length. I think that It is not a standard ball mill. Now I want to calculate the power draw of this ball mill and know how much must be the loaded ball in this ball mill.
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1. Closed Circuit = W 2. Open Circuit, Product Top-size not limited = W 3. Open Circuit, Product Top-size limited = W to 1.25 W Open circuit grinding to a given surface area requires no more power than closed circuit grinding to the same surface …
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Measurement results of two ball mills in a real ceramic manufacturing plant showed that the proposed calculation models could achieve an accuracy of more than 96% for predicting the ball mill ...
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ball mill as a function of mill`s power draw or investigation on the ball filling ratio under batch wet conditions, due to load density alters [2, 3]. ... draw out mill`s internal load, and calculate the weight of ball part and stony part, separately. However, maybe this method will be unusable due to its operational ...
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Analysis of the historic mill power draw, site data on ball filling provided by mill grind-outs, and applying the Morrell Power model (Morrell, 1993) to back-calculate approximate mill filling ...
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The following power draw calculations apply to wet overflow ball mills* .The approach to calculate ball mill power draw is the same as for rodmills. However, there is an additional step for ball mills with insidediameters greater than 3 meters (10 feet). In such mills, media sizenoticeably affects power draw and must be considered in ...
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Formulas given for mill power draw modelling are empirical, and fit around field data over the normal operating range of about 30 to 45% charge level. Theoretically, power …
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as a kinetic and potential energy balance to describe the power draw of a mill charge. The power drawn from a cylindrical (shell-supported) mill is given by Equation 1. . 1 1 ˘ˇˆ˙˝˘ ˛˚ ˜ 0.6 # $ %# $ ˘ˇˆ˙˝˘ ˛˚ ˜&'( 1 ).* +,-./˚ ˜ (1) Where: • A and K are empirical fitting factors
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Rod mills are normally operated with a 32 to 40 percent charge by volume which during operation, becomes a 40 to 50% charge, with a bulk density considerably lower than that of stacked rods. This chart shows the impact a mill's grinding ball load has on the mill's motor power draw. Process Machinery Reference Manual
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You can read all the details of this now "Biblical" grinding power requirement calculation formula in Fred Bond's original paper. ... Ball Mill Grindability Test was conducted by standard practice using 100-mesh (150 pm) closing screens. The ball mill work index is shown below. BM Wi (kW-hr/st) = 17.97 ...
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Yesterday I calculated the power draw of our ball mill. I attach a graph of it. Is it possible to have calculated mill power draw to be greater than mill motor HP? Calculated mill power draw is 1,509 HP; Mill motor HP is 1,500 HP According to the calculations, at 54% mill volumetric loading, max power draw of 1,796 HP is obtained.
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These mills typically grind ROM ore in a single stage. A large example of such a mill was converted from a single-stage milling application to a semi autogenous ball-mill-crushing circuit, and the application is well described. This refers to high-aspect AG/SAG mills. Ball Charge Motion inside a SAG Mill. With a higher density mill charge.
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