# question on critical speed of a ball mill

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The critical speed of ball mill is given by where R = radius of ball mill r = radius of ball But the mill is operated at a speed of 15 rpm Therefore the mill is operated at 100 x 15/30.7 = 48.86 of critical speed.

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Answer on Question #59839 Physics Mechanics Relativity A bowling ball rolls 32 meters in 0.8 seconds Find the average speed in m/s of the bowling ball in m/s Find v Given s=32 m t=0 8 s

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Initial velocity of the ball u = 29.4 m/s At maximum height the velocity of the ball becomes zero.Final velocity of the ball v = 0 Acceleration a =g =9.8 m/s2 Using third equation of motion Height to which the ball rises is given by

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The operating principle of the ball mill consists of following steps In a continuously operating ball mill feed material fed through the central hole one of the caps into the drum and moves therealong being exposed by grinding media The material grinding occurs during impact falling grinding balls and abrasion the particles between the balls Then discharge of ground material performed

Get Price### QUESTION 3 CRITICAL SPEED OF THE OUTPUT SHAFT 30

Transcribed image text QUESTION 3 CRITICAL SPEED OF THE OUTPUT SHAFT 30 3.1 The gear is mid mounted between the ball bearings as shown in the side view 30 of the gear system for driving the roller machine Figure 2 The critical speed must be significantly higher than the operating speed Assume the ball bearings supporting the output shaft are stiff and act as simple supports.

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The point where the mill becomes a centrifuge is called the Critical Speed and ball mills usually operate at 65 to 75 of the critical speed Ball Mills are generally used to grind material 1/4 inch and finer down to the particle size of 20 to 75 microns.

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Question The critical speed of the ball mill is less than 45 of operating speed Now calculate the operating speed of the ball mill which has diameter of 900 mm Diameter of ball is 80 mm a 47 rpm b 68 rpm c 32 rpm d 21 pm

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Tube mill compared to ball mill For the preliminary breaking of hard rock we use a Chemical Engineering BasicsPart 1 more Online Exam Quiz Materials and ConstructionPart 10 Materials and ConstructionPart 11 Mechanical OperationsPart 2 Mechanical OperationsPart 3 Mechanical OperationsPart 4 Mechanical OperationsPart 6

Get Price### SAGMILLING Mill Critical Speed Determination

The Critical Speed for a grinding mill is defined as the rotational speed where centrifugal forces equal gravitational forces at the mill shell s inside surface This is the rotational speed where balls will not fall away from the mill s shell Result #1 This mill would need to spin at RPM to be at 100 critical speed.

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NOTE 3/27/08 This article is a summary of the published literature concerning batted ball speed and bat WEIGHT However a great deal of recent research clearly indicates that the distribution of weight as measured by the moment of inertia is far more important than the weight itself As a result some of the conclusions summarized below are no longer entirely realistic.

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Describe the components of ball mill Explain their understanding of ball mill operation Explain the role of critical speed and power draw in design and process control Recognize important considerations in ball mill selection Reading Lecture In ball mills steel balls or hard pebbles to break particle based on impact and attrition.

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Mechanical Operations MCQ Questions Answers Chemical Engineering Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Section 7 26 In case of a ball mill A Coarse feed requires a larger ball B Fine feed requires a larger ball C Operating speed should be more than the critical speed D.

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Physics questions and answers Question 1 A ball of mass m is thrown with initial speed v in vertically upward direction from the ground at time t = 0 In addition to the gravitational force the air resistance force F = bu acts on the ball in the downward direction as it moves in upward direction b is a given positive constant

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The operating speed of a ball mill should be the critical speed a Less than b Much more than c At least equal to d Slightly more than The operating speed of a ball mill should be the critical speed a Less than b Much more than c At least equal to d Slightly more than Related Questions on Mechanical Operations.

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Rose and Sullivan showed critical rotation speed N c to reach the final stage i.e centrifugal motion 1 N c = 1 2π 2g D−2r where D is the inner diameter of a jar and r is the radius of balls All throughout they used the critical rotation speed as the constant value for given conditions of ball mill .

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2 Critical speed of a ball mill depends on A the radius of the mill shell and the radius of the particles B the radius of the mill shell and the density of the particles C the radius of the balls and the radius of the particles D the radius of the balls and the radius of the mill shell

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A ball mill is designed to run at 25 total filling degree with a fixed speed of 75 CS critical speed A lifter angle of 30 degrees will produce trajectories where the grinding media fall on the toe of the charge thereby limiting the risk of breakage Due to the lack of available ore the plant decides to drop the filling degree to 15 .

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Size and Number of the balls Nature of the balls Rotation speed 8 Vibration ball mills Planetary ball mills 9 Vibration Mills 10 Mixer Mill MM 400 11 Feed material hard medium hard soft brittle elastic fibrous Material feed size ≤ 8 mm Final fineness 5 µm

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A ball is dropped from a height of 18 m The speed of the ball when it touches the ground has to be determined An object with an initial velocity u m/s accelerating at a m/s 2 has a velocity v

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A ball is thrown directly downward with an initial speed of 7.05 m/s from a height of 30.2 m The question to use is the one where we have the final the funnel this place when he goes to the initial This place this place one of these things velocity It was a time on this 1/2 G velocity times the time I was the height initial who

Get Price### Critical rotation speed for ball millingScienceDirect

Rose and Sullivan showed critical rotation speed Nc to reach the final stage i.e centrifugal motion 1 N c = 1 2π 2g D−2r where D is the inner diameter of a jar and r is the radius of balls All throughout they used the critical rotation speed as the constant value for given conditions of ball mill.

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While your swing speed is very criticalgolf ball speed is a better measurement of how efficiently you transferred the energy of your swing to the ball For example if you had a golfer with a driver swing speed of 100 mph but with very efficient impact conditions they could hit the ball farther than someone who swung inefficiently at 110

Get Price### Mill Critical Speed Calculation

The mill was rotated at 63 of the critical speed The position of the balls at the end of five revolutions is shown in Figure 2 It is seen that using a low coefficient of friction at the walls balls tend to flow down the surface of the charge and a toe begins to form As the friction at the wall increases cataracting motion is observed.

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14 a What is the critical speed in rpm of a ball mill having a inside diameter of 120 cm charged with 7.5 cm spherical balls Answer N c = 40 rpm b Calculate the operating speed of the ball mill from the following data Diameter of the ball mill is 500 mm diameter of the balls are 40 mm If the operating speed is 50 of the critical speed of the mill.

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by mill operating parameters It is hoped that this work can be used as a precursor to the development of a model that can predict liberation given the various ranges of operating parameters Mill speed mill charge ball size and wet grinding are the parameters which have been selected for the present study It is hoped that the analysis of the

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Chemical Engineering questions and answers What is the critical rotation speed for a ball mill of 1.6 m diameter charged with 80 mm diameter balls a 0.4 PS b 24.26 rpm C 34.3 rpm d 0.7 rps e 36.82 rpm Question What is the critical rotation speed for a ball mill of 1.6 m diameter charged with 80 mm diameter balls

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What rotational speed in rpm would you recommend for a ball mill that is 1000 mm in diameter and charged with 70 mm balls Assume that the mill is operating at 68 of the critical speed.

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Question View in Hindi The speed of the ball going towards the boundary line is 6 m/s and the fielder follows it at a speed of 6.4 m/s if the initial distance between the fielder and the ball is 2.4 meters then how much time will it take to catch the ball

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MCQs Critical Speed Nc of a ball mill is given by where R1 and R2 are radii of ball mill and the ball respectively Category Chemical Engineering Mcqs Published by T Code Scripts Related Questions Flow of filtrate through the cake in a p Filtrate flow rate in case of a rotary d

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Question A ball is tossed upward from a bridge that is 27 meters high at a speed of 5 meters per second What is the height of the ball at 1 second if the height is given in meters by h t = 4.912 5t 27 where t is seconds If necessary round your answer to the nearest tenth of a

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The critical speed of the mill c is defined as the speed at which a single ball will just remain against the wall for a full cycle At the top of the cycle =0 and Fc Fg 8.5 mp 2 cDm 2 mpg 8.6 c 2g Dm 1/2 8.7 The critical speed is usually expressed in terms of the number of revolutions per second Nc c 2 1 2 2g Dm 1/2 2 9.81 1/2

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Critical speed in rpm = 42.3/sqrt Dd with D the diameter of the mill in meters and d the diameter of the largest grinding ball you will use for experiment also expressed in meters

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In order for the ball to move upwards its initial velocity must be greater than zero As the ball rises its velocity decreases until it reaches its maximum height where it stops and then begins to fall As the ball falls its speed increases Therefore at maximum altitude the velocity of the ball must be zero.

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Oct 13 2020 calculating critical speed in a ball mill How ToCalculate Critical SpeedOfBall MillThecritical speedof themillc is defined as thespeedat which a singleballin equation 814 d is the diameter inside themillliners and le is the rod andball millsin mular al and bhappu r b editors mineral processing plant design.

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Turn over P39847A ©2012 Pearson Education Ltd 1/1/1/1 P39847A0128 Instructions tt Use black ink or ball point pen Fill in the boxes at the top of this page with your name centre number and candidate number.t t Answer all questions Answer the questions in the spaces provided

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Construction Of Ball Millcritical Speed Of Ball Mill Formula ball mill operating speedmechanical operations solved the critical speed of ball mill is given by where r = radius of ball mill r = radius of ball for r = 1000 mm and r = 50 mm n c = 30.7 rpm but the mill is operated at a speed of 15 rpm therefore the mill is operated at 100 x 15/30.7 = 48.86 of critical speed..mill

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Ball mills have been successfully run at speeds between 60 and 90 percent of critical speed but most mills operate at speeds between 65 and 79 percent of critical speed Rod mills speed should be limited to a maximum of 70 of critical speed and preferably should be in

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Answer to poll question 1 You hit a slight draw with a driver and ball speed = 154 mph spin = 2500 RPM Vertical launch = 13 deg with a lateral of 6 yds.

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Chemical Engineering Question #226953 Find the critical speed of the ball mill in RPM a 20.1 b 30.7 c 49.6 J 67.8 e None 0 Expert s answer.

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Investigations were carried out in a laboratory ball mill having the size of DxL = 160x200 mm with a ribbed inside surface of the drum The mill ball loading was 40 by volume the rotation rate was equal to 85 of the critical speed Balls were made from steel S4146 extra high quality having hardness 62 ± 2 HRC according to Rockwell.

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