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Fine grinding, to P80 sizes as low as 7 μm, is becoming increasingly important as mines treat ores with smaller liberation sizes. This grinding is typically done using stirred mills such as the Isamill or Stirred Media Detritor. While fine grinding consumes less energy than primary grinding, it can still account for a substantial part of a …
Ball Mill Motor/Power Sizing Calculation Ball-shaped Mill Design/Sizing Calculator To capacity required to grind a material from a giving feed size the a gives …
Based on his work, this formula can be derived for ball diameter sizing and selection: Dm <= 6 (log dk) * d^0.5 where D m = the diameter of the single-sized balls in mm.d = the diameter of the largest chunks of ore in the mill feed in mm. dk = the P90 or fineness of the finished product in microns (um)with this the finished product is ...
Define and calculate the grinding efficiency of the ball mill in a ball mill circuit. Relate overall ball mill circuit output and circuit efficiency to specific design and operating …
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 ...
Do you need a quick estimation of a ball mill's capacity or a simple method to estimate how much can a ball mill of a given size (diameter/lenght) grind for tonnage a product P80 size? Use these 2 tables to get you close. No BWi Bond Work Index required here BUT be aware it is only a crude approximation for "most soft ores" from F80 1 cm ...
Where N (kW) represented the power of ball mill pinion shaft; K ωb (kW/t) was the power for per ton ball medium; G (t) represented the weight of media loaded in the ball mill. Usually, the power of the ball mill pinion shaft was directly proportional to the motor power of the ball mill, and the correlation coefficient was 1.05–1.20.
To calculate the axis speed at peak torque, enter the following: – Motor Torque Peak: Ideally, you'll get this looking at a power curve from the manufacturer. If you don't have one, I suggest trying 2000 rpm for steppers and 3000 rpm for servos. Most manufacturers can provide you with this information and it is worth having.
Wet Ball Mill = kg kWh = 0.16(A i-0.015) 0.33; Dry Ball Mill = kg / kWh = 0.023A i 0.5; Replacement Ball Size. Rowland and Kjos proposed the use of their equation for the determination of the initial and replacement media …
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) diameter inside liners, the top size of the balls used affects the power drawn by the mill. This is called the ball size factor S.
Equation 1 is multiplied by the factor of 1.08. A multi-compartment ball mill consists of two or more grate discharge ball mills in series. The same equation is used to calculate the power that each ball mill compartment should draw. The total power is the sum of the power calculated for each of the separate compartments.
You can use the lab data from a standard bond ball mill test to calculate this alternative index. Helena Russell. 8 years ago. ... ( Kw) =f( Mill diameter 3,RPM 1.27,Filling Degree, Length, pulp Sg) (unknown) 8 years ago ... When the motor is coupled direct to the pinionshaft, motor output power is mill pinionshaft power. If a speed reducer or ...
Figures 5 and 6 respectively. Accurate measurements of the ball filling can only be made after the mill is ground out. In this case the mill is operated with the feed turned off until all of the ore has exited the mill. Measurements of the ball level within the mill can then be made. Figure 7 shows an example of the balls in a mill after a ...
As can be seen in the equation, the mill power (kW) being used 'effectively' (on coarse particles) is simply the product of the mill power and the CSE, which is the percentage of the mill solids ... From the ball mill feed size distribution calculate the %+75 μ as: 100 – 19.3 = 80.7% +75 μ. 2. From the ball mill discharge size ...
To participate in the 911Metallurgist Forums, be sure to JOIN & LOGIN; Use Add New Topic to ask a New Question/Discussion about Grinding.; OR Select a Topic that Interests you.; Use Add Reply = to Reply/Participate in a Topic/Discussion (most frequent). Using Add Reply allows you to Attach Images or PDF files and provide a more complete input.; Use …
RLA - "Running Load Amps" - current drawn during normal operation of electric motor. FLA - "Full Load Amps" - amount of current drawn when full-load torque and horsepower is reached for the motor. FLA is usually determined in laboratory tests. Note! - in the calculator above FLA is RLA + 25% . 1 hp = 0.745 kW.
Ball Mill Motor Power Draw Sizing and Design Formula. The following equation is used to determine the power that wet grinding …
In the present work, equations were derived, giving the specific grinding energy w as a function of: the feed D (mm) and product size d. f (mm) (both 80% cumulative …
What are the dimensions of the ball mill you are looking at? 40% ball charge is quite high (unless you are looking at a small mill). A difference (duty vs. maximum) of 5% to 10% is fairly typical and you would likely struggle to perceive an energy efficiency difference between the two operating points.
Milling Horsepower Calculator. Calculate the horsepower required for a milling operation based on the feed rate and depth of cut, which are used to determine the material removal rate (or metal removal rate). Also required is the unit power, which is a material property describing the amount of power required to cut that material.
Calculate Tangential Force, Torque, and Machining Power for End Milling Applications. ... End Mill Nomenclature End Mill Nomenclature. d1 Effective cutting diameter. ... HPc kW. P m at the motor hp kW. Join the Community. Get the latest updates on product innovations, expert tips, events, promotions, and training. ...
If your motor has an efficiency of 0.9 and you measure 1000 kW at the motor input, then the motor output power you would measure (with a torque device) is 900 kW. This is why you are measuring more input power than the rated power; the rated "input" power would be 1500 HP divided by the motor efficiency.
A generalized SAG mill power draw equation developed by Austin, is given by: where the parameters used in the model are defined as: mp= net mill power (kW) K = a constant (kW/ton m0.5) D = mill internal diameter (m) L = mill length (m) J = fractional volume of mill filled by total charge. εB = effective porosity of the total charge.
How to Calculate Charge Volume in Ball or Rod Mill | …. To calculate grinding media charge for continuous type ball mill, M = 0.000676 x D2 x L Example ….
In terms of this concept, the energy efficiency of the tumbling mill is as low as 1%, or less. For example, Lowrison (1974) reported that for a ball mill, the theoretical energy for size reduction (the free energy of the new surface produced during grinding) is 0.6% of the total energy supplied to the mill setup.
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 ; BM Wi (kW-hr/mt) = 19.81; Bond Ball Mill. ... In each of the 15 ores the data from the grindability test at 48 mesh alone were used to calculate the Wi values at 28, 35 ...
INTRODUCTION The energy consumption for grinding, according to Bond (1961), is deter- mined by the formula: / 10 10 (I) The work index is determined by grinding experiments carried out in a labo- ratory Bond ball mill. Based on the results of grinding experiments, numerical values of the work index Wi are calculated according to the …
Step 4 – Converting the result to kW or HP. Assuming the input values are in Inches and KC is in KPSI the result should be divided by 400 to get the power in HP units. Assuming the input values are in millimeters and KC is in Mpa (N/mm 2) the result should be divided by 60,000 to get the power in kW.
Therefore, a 350-hp motor is required and this in turn indicates that an 812 (8′ x 12′) Rod Mill is required. In the same way Fig. 3 indicates that an 800-hp motor and a 101/214 or 10.5′ by 14′ Ball Mill is required. Following is a condensed tabulation of the above selections. Sizing a Ball or Rod Mill
Ball Mill Motor/Power Sizing Calculation. 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 ...
Gross Power Draw and Specific Energy Calculator for Autogenous Grinding (AG), Semi-Autogenous Grinding (SAG) and Ball Mills. Exit Mill Calculator.
Thus the power to drive the whole mill. = 49.5 + 66.0 = 115.5 h.p. = 86 kW. From the published data, the measured power to the motor terminals is 103 kW, and so the power demand of 86 kW by the mill …
In order to determine the performance you'll need from the motor, there are three factors to calculate; Moment of Inertia, Torque and Speed. (Refer to the below sections on calculations for each.) Once you've calculated the inertia, torque and speed for the motor you'll select the type of motor based on the required specifications.
