The ball charge is a function of the bulk fraction of the SAG mill volume (Jb) occupied by balls; the ore retained in the mill is the result of the volumetric filling which depends on the ore size distribution (specially the % +6″ and the % −6″ +1″), on the rotational speed (N/Nc) and on the solid concentration by weight fraction inside ...
SAG Mill power draw models are used in mill design and grinding circuit modelling to predict how much power will be consumed by a particular mill geometry and operating …
The equation relates the amount of new product-sized material produced by the ball mill circuit to four key factors: mill power draw, classification system eficiency (CSE), ore …
TECHNICAL NOTES 8 GRINDING R. P. King - Mineral Tech. 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 …
The following are factors that have been investigated and applied in conventional ball milling in order to maximize grinding efficiency: a) Mill Geometry and Speed – Bond (1954) observed grinding efficiency to be a function of ball mill diameter, and established empirical relationships for recommended media size and mill speed …
The feed enters one end of the ball mill, and discharges out the other end. Ball mills vary greatly in size, from large industrial ball mills measuring more than 25 ft. in diameter to small mills used for sample preparation in laboratories. Rod mills are similar to ball mills and use metal rods as the grinding media. Pebble mills use rock ...
• P is the power evolved at the mill shell, kW • PN is an empirical "power number" which varies with mill filling and speed, unitless • ρCharge is the density of the mill charge as given in Equation 3, t/m³ Ball charge is not explicitly used in the power formula, but is considered in the mill charge density formula: %(1 234 567ˆˆ ...
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, …
In the previous discussion the fact was established that the work done by a ball when it strikes at the end of its parabolic path is proportional to its weight and velocity; then, since the velocity may be considered as constant for all the balls in the mill, the work done by a ball is proportional to its weight. Since the amount of ore crushed varies as …
EURASIAN MINING • 1. 2015 Technology and technics of ore preparation processes 7 feed for the rod mill, i.e. 10000 μm in accordance with Table. The value of P 80 is accepted based on the required grain-size characteristics of the ball mill discharge.
Figure 3a and 3b gives the results of the computer calculation. The mill power at the pinionshaft for a 30% volume charge is the sum of: Figures 3a & 3b give the power for an autogenous mill. Figures 4a and 4b are for the same size mill with a ball charge of 6% of mill volume (290 lbs. per cubic foot).
and size distribution of the ore in the mill. Mill power calculations were performed based on conditions at the time of sampling, in addition to considering other scenarios. The Bond formula and ... of 34.8 % for the rod compartment and 65.2 % for the ball compartment. The Bond formula (Equation 2) was used to calculate the required power for ...
This article presents a novel approach to calibrating the digital twin of a laboratory mill used for copper ore milling. By integrating computer vision techniques for real-time data extraction and employing DualSPHysics simulations for various milling scenarios, including balls only, balls with ore, and balls with slurry, we achieve a high …
The original SAG mill control loop, a mill motor power draw set point of 5200 Amperes controlling the coarse ore feeder speeds, was soon found to give excessive variation in the mill ore charge volume and somewhat less than optimal power draw.
The basic work index equation is: W = 10 Wi/√P – 10 Wi/√F(1) where W is the work input required in kilowatt hours per short ton to grind from 80% passing F microns to 80% passing P microns, and Wi is the work index, or the grinding resistance parameter. It represents the energy input required in kilowatt hours to reduce a s…
online live calculators for grinding calculations, Ball mill, tube mill, critical speed, Degree of filling balls, Arm of gravity, mill net and gross power
The depth of the centrifuged layer increases with the mill speed N. 5.2. Variation of torque and power with mill speed Fig. 2 shows the variation of the average torque and power with mill speed for the ball mill described above with a fill level of 50%. The torque increases slowly until the peak is attained around N s 80%.
SAG mill optimization to feed ball mill optimized P80. Most SAG mill are not optimized for the combined SAG & Ball mill throughput such as: SAG & Ball mill % ball content SAG % ore content SAG grate size and end mill design including grate geometry, location, shape, pan cavity, recycle % in pan cavity, et. al.
If you have done proper test work and assumed your Work index is as you provided above quickly I can estimate that your SAG throughput is around 517 t/h and if the total % of mill charge is 25 % of the total mill volume, then you can assume the following assumption .i.e. mass proportion of grinding body to ore be 15% steel balls and 10 % ore (1 ...
Fig. 2 shows the variation of the average torque and power with mill speed for the ball mill described above with a fill level of 50%. The torque increases slowly until the peak is attained around N=80%.As the amount of cataracting increases, the balance of the charge improves and the torque required to maintain the asymmetric charge position …
Technology and technics of ore preparation processes 5 The ore pretreatment flow charts in use at most high-productive processing plants designed in the last decade are based on semiautogenous (SAG) milling and involve as a rule primary wet autogenous mill (WAM) and a series of ball mills. WAM is customary chosen either based on examination
First stage, will be broken into two parts as well, you use a Bond rod mill work index for the coarse component of the ore (+2.1 mm) and the Bond ball mill work index for the fine component (-2.1 mm). It would look like this: ... The power at the pinion of the ball mill is 1800 kW. F80 = 80% passing size of the circuit feed, in microns = 2500 um.
Power consumption management and simulation of optimized operational conditions of ball mills using the Morrell Power model: A case study March 2022 DOI: 10.17794/rgn.2022.2.11
A linkedin group was recently discussing this by asking: I've tried to estimate AG/SAG Mill power requirements using several different methods: (1) Using the results of SMC data (2) Using SAG Power Index (SPI) data (3) Using the 1989 Barratt method updated on Alex Doll's Web site (February 16, 2015) (3) Using Don Burgess' …
List and describe the four elements of the functional performance equation for ball mill circuits. Define and calculate the classification system efficiency of a ball mill circuit. …
International Journal of Mineral Processing, 25 (1989) 41-46 41 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands Calculation of Energy Required for Grinding in a Ball Mill N.M. MAGDALINOVIC University of Belgrade, Technical Faculty at Bor, 19210 Bor (S.F.R. Yugoslavia) (Received June 9, 1987; …
For rod, ball, or pebble mills the peak is usually near Vp = .50, while actual observations as low as V= .42 have bean made in some ball mills (Rowland, 1973). See Figure 2. Power draw is not …
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 ...
• Overflow ball mill: Discharge the ore through hollow shaft. • Grid ball mill: Discharge the ore through the plaid plate. • Peripheral ball mill: Discharge the ore …
For any circuit, whether a crushing circuit, a rod mill, or a closed ball mill circuit, the Work Index always means the equivalent amount of energy to reduce one ton of the ore from a very large size to 100 um. The sample was received crushed appropriately for the ball mill test.
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