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
by

1 Answer

Answer :

(A) Less than
by

Related questions

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) None of these

Description : 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) None of these

Last Answer : (A) Coarse feed requires a larger ball

Actual operating speed of a ball mill may vary from 65 to 80% of the critical speed. Which of the following duties would require the ball mill to be operated at maximum percentage of critical speed? (A) Wet grinding in low viscous suspension (B) Wet grinding in high viscous suspension (C) Dry grinding of large particles (upto 1.25 cms) (D) Dry grinding of large particles in un-baffed mills

Description : Actual operating speed of a ball mill may vary from 65 to 80% of the critical speed. Which of the following duties would require the ball mill to be operated at maximum percentage of critical speed? (A) ... of large particles (upto 1.25 cms) (D) Dry grinding of large particles in un-baffed mills

Last Answer : (D) Dry grinding of large particles in un-baffed mills

What is the critical rotation speed in revolutions per second, for a ball mill of 1.2 m diameter charged with 70 mm dia balls? (A) 0.5 (B) 1.0 (C) 2.76 (D) 0.66

Description : What is the critical rotation speed in revolutions per second, for a ball mill of 1.2 m diameter charged with 70 mm dia balls? (A) 0.5 (B) 1.0 (C) 2.76 (D) 0.66

Last Answer : (D) 0.66

Critical Speed (Nc ) of a ball mill is given by (where R1 and R2 are radii of ball mill and the ball respectively). (A) Nc = (1/4π). √(g/R1 - R2 ) (B) Nc = (1/2π). √(g/R1 - R2 ) (C) Nc = (1/π). √(g/R1 - R2 ) (D) Nc = (1/2π). √(R1 - R2 /g)

Description : Critical Speed (Nc ) of a ball mill is given by (where R1 and R2 are radii of ball mill and the ball respectively). (A) Nc = (1/4π). √(g/R1 - R2 ) (B) Nc = (1/2π). √(g/R1 - R2 ) (C) Nc = (1/π). √(g/R1 - R2 ) (D) Nc = (1/2π). √(R1 - R2 /g)

Last Answer : (B) Nc = (1/2π). √(g/R1 - R2 )

The main differentiation factor between tube mill and ball mill is the (A) Length to diameter ratio (B) Size of the grinding media (C) Final product size (D) Operating speed

Description : The main differentiation factor between tube mill and ball mill is the (A) Length to diameter ratio (B) Size of the grinding media (C) Final product size (D) Operating speed

Last Answer : (A) Length to diameter ratio

For efficient grinding, ball mills must be operated (A) At a speed less than the critical speed (B) At a speed more than the critical speed (C) At a speed equal to the critical speed (D) With minimum possible small balls

Description : For efficient grinding, ball mills must be operated (A) At a speed less than the critical speed (B) At a speed more than the critical speed (C) At a speed equal to the critical speed (D) With minimum possible small balls

Last Answer : (A) At a speed less than the critical speed

For achieving maximum capacity of the ball mill, the ball charge should be equal to about __________ percent of the ball mill volume. (A) 10 (B) 25 (C) 50 (D) 75

Description : For achieving maximum capacity of the ball mill, the ball charge should be equal to about __________ percent of the ball mill volume. (A) 10 (B) 25 (C) 50 (D) 75

Last Answer : (C) 50

The energy consumed by a ball mill depends on (A) Its speed (B) Its ball load (C) The density of the material being ground (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

Run of mine (ROM) coal is crushed by a __________ for use in domestic ovens. (A) Jaw crusher (B) Hammer crusher (C) Ball mill (D) Tube mil

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__________ balls capable of grinding the feed in a ball mill gives the maximum efficiency. (A) Cast iron (B) Minimum size (C) Maximum size (D) Elliptical

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A __________ mixer resembles a ball mill without balls. (A) Banbury (B) Pug mill (C) Tumbling (D) Pan

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Maximum size reduction in a ball mill is done by the, __________ action. (A) Attrition (B) Compression (C) Impact (D) Cutting

Description : Maximum size reduction in a ball mill is done by the, __________ action. (A) Attrition (B) Compression (C) Impact (D) Cutting

Last Answer : (C) Impact

In a ball mill, the volume occupied by the balls (when the mill is stopped) is about __________ percent of the volume of the mill. (A) 35 (B) 50 (C) 70 (D) 85

Description : In a ball mill, the volume occupied by the balls (when the mill is stopped) is about __________ percent of the volume of the mill. (A) 35 (B) 50 (C) 70 (D) 85

Last Answer : (B) 50

Grinding efficiency of a ball mill is of the order of __________ percent. (A) 1-5 (B) 40-50 (C) 75-80 (D) 90-95

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The economic life of a large chemical process plant as compared to a small chemical plant is (A) Only slightly more (B) Much more (C) Slightly less (D) Almost equal

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Critical energy should be __________ the neutron binding energy of the atom in order to initiate a nuclear fission. (A) Equal to (B) Less than (C) More than (D) Either more or less

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Last Answer : (C) More than

A gas can be liquefied by pressure alone only, when its temperature is __________ its critical temperature. (A) Less than (B) More than (C) Equal to or higher than (D) Less than or equal to

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A tube mill compared to a ball mill (A) Has a higher length/diameter ratio(B) Produces a coarser product(C) Has a higher diameter/length ratio(D) Uses much larger balls

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Last Answer : (A) Has a higher length/diameter ratio

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Last Answer : (D) All (A), (B) and (C)

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