__________ 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

__________ 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
by

1 Answer

Answer :

(B) Minimum size
by

Related questions

Balls in a ball mill are usually made of (A) Steel (B) Cast iron (C) Stainless steel (D) Bronze

Description : Balls in a ball mill are usually made of (A) Steel (B) Cast iron (C) Stainless steel (D) Bronze

Last Answer : (A) Steel

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

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

Last Answer : (A) 1-5

A tube mill as compared to a ball mill (A) Employs smaller balls (B) Gives finer size reduction but consumes more power (C) Has larger length/diameter ratio (>2 as compared to 1 for ball mill) (D) All (A), (B) and (C)

Description : A tube mill as compared to a ball mill (A) Employs smaller balls (B) Gives finer size reduction but consumes more power (C) Has larger length/diameter ratio (>2 as compared to 1 for ball mill) (D) All (A), (B) and (C)

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

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

The mechanism of size reduction by a hammer mill is by impact and attrition between the (A) Grinding element & the housing (B) Feed particles (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : The mechanism of size reduction by a hammer mill is by impact and attrition between the (A) Grinding element & the housing (B) Feed particles (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) and (B)

In case of grinding in a ball mill (A) Wet grinding achieves a finer product size than dry grinding (B) Its capacity decreases with increasing fineness of the products (C) Grinding cost and power requirement increases with increasing fineness of the products (D) All (A), (B) and (C)

Description : In case of grinding in a ball mill (A) Wet grinding achieves a finer product size than dry grinding (B) Its capacity decreases with increasing fineness of the products (C) Grinding cost and power requirement increases with increasing fineness of the products (D) All (A), (B) and (C)

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

For grinding of cereals, grains, spices, pigments, saw dust, cork etc., the most extensively used size reduction equipment is a(A) Buhrstone mill(B) Ball mill(C) Crushing rolls(D) Hammer mill

Description : For grinding of cereals, grains, spices, pigments, saw dust, cork etc., the most extensively used size reduction equipment is a (A) Buhrstone mill (B) Ball mill (C) Crushing rolls (D) Hammer mill

Last Answer : (A) Buhrstone mill

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

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

Out of the following size reduction equipments, the maximum feed size can be accepted by the (A) Tube mill (B) Ball mill (C) Jaw crusher (D) Jet pulveriser

Description : Out of the following size reduction equipments, the maximum feed size can be accepted by the (A) Tube mill (B) Ball mill (C) Jaw crusher (D) Jet pulveriser

Last Answer : (C) Jaw crusher

Wet grinding in a revolving mill __________ as compared to dry grinding. (A) Gives less wear on chamber walls (B) Requires more energy (C) Increases capacity (D) Complicates handling of the product

Description : Wet grinding in a revolving mill __________ as compared to dry grinding. (A) Gives less wear on chamber walls (B) Requires more energy (C) Increases capacity (D) Complicates handling of the product

Last Answer : (C) Increases capacity

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

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

Last Answer : (C) Tumbling

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

Liners of a ball mill are never made of (A) Lead (B) Alloy steel (C) Rubber or ceramic material (D) Cast iron

Description : Liners of a ball mill are never made of (A) Lead (B) Alloy steel (C) Rubber or ceramic material (D) Cast iron

Last Answer : (A) Lead

Balls for ball mills are never made of (A) Forged/cast steel (B) Lead (C) Cast iron (D) Alloy steel

Description : Balls for ball mills are never made of (A) Forged/cast steel (B) Lead (C) Cast iron (D) Alloy steel

Last Answer : (B) Lead

A pebble mill (A) Is a ball mill (B) Employs flints or ceramic pebbles as the grinding medium (C) Is a tube mill lined with ceramic or other non-metallic liner (D) Both (B) and (C)

Description : A pebble mill (A) Is a ball mill (B) Employs flints or ceramic pebbles as the grinding medium (C) Is a tube mill lined with ceramic or other non-metallic liner (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

Ball mill is used for (A) Crushing (B) Coarse grinding (C) Fine grinding (D) Attrition

Description : Ball mill is used for (A) Crushing (B) Coarse grinding (C) Fine grinding (D) Attrition

Last Answer : (C) Fine grinding

Close circuit grinding by a ball mill with air sweeping employs a (A) Classifier (B) Cyclone separator between mill & classifier (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Close circuit grinding by a ball mill with air sweeping employs a (A) Classifier (B) Cyclone separator between mill & classifier (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Steel balls for ball bearings are generally made of __________ steel. (A) Cast (B) Stainless (C) Free carbon (D) Carbon chrome

Description : Steel balls for ball bearings are generally made of __________ steel. (A) Cast (B) Stainless (C) Free carbon (D) Carbon chrome

Last Answer : (D) Carbon chrome

In ball mill operation, the feed size (Df in meters) and the ball diameter (Db in metres) are related as (where, K = grindability constant (varying from 0.9 to 1.4 in increasing order of hardness)) (A) Db 2 = K.Df (B) Db = K.Df (C) Db 3 = K.Df (D) Db 2 = K.Df

Description : In ball mill operation, the feed size (Df in meters) and the ball diameter (Db in metres) are related as (where, K = grindability constant (varying from 0.9 to 1.4 in increasing order of hardness)) (A) Db 2 = K.Df (B) Db = K.Df (C) Db 3 = K.Df (D) Db 2 = K.Df

Last Answer : (A) Db 2 = K.Df

Feed size of ≥ 25 cms can be accepted by (A) Ball mill (B) Rod mill (C) Fluid energy mill (D) Jaw crusherFeed size of ≥ 25 cms can be accepted by(A) Ball mill(B) Rod mill(C) Fluid energy mill(D) Jaw crusher

Description : Feed size of ≥ 25 cms can be accepted by (A) Ball mill (B) Rod mill (C) Fluid energy mill (D) Jaw crusher

Last Answer : (D) Jaw crusher

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

Which of the following grinding mills has the horizontally arranged rods as the grinding elements thereby delivering more uniform granular products with minimum fines? (A) Compartment mill (B) Rod mill (C) Pebble mill (D) Tube mill

Description : Which of the following grinding mills has the horizontally arranged rods as the grinding elements thereby delivering more uniform granular products with minimum fines? (A) Compartment mill (B) Rod mill (C) Pebble mill (D) Tube mill

Last Answer : (B) Rod mill

Which of the following gives the work required for size reduction of coal to -200 mesh in a ball mill most accurately? (A) Rittinger's law (B) Kick's law (C) Bond's law (D) None of these

Description : Which of the following gives the work required for size reduction of coal to -200 mesh in a ball mill most accurately? (A) Rittinger's law (B) Kick's law (C) Bond's law (D) None of these

Last Answer : (A) Rittinger's law

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

Tube mill compared to ball mill (A) Produces finer products (B) Is long in comparison with its diameter (C) Uses smaller balls (D) All (A), (B) & (C)

Description : Tube mill compared to ball mill (A) Produces finer products (B) Is long in comparison with its diameter (C) Uses smaller balls (D) All (A), (B) & (C)

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

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

Description : 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

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

Pebble mills are tumbling mills widely used for grinding in the manufacture of paints & pigments and cosmetic industries, where iron contamination in the product is highly objectionable. Pebbles used in pebble mill are made of (A) Bronze (B) Stainless steel (C) Flint or porcelain (D) Concrete

Description : Pebble mills are tumbling mills widely used for grinding in the manufacture of paints & pigments and cosmetic industries, where iron contamination in the product is highly objectionable. Pebbles used in pebble mill are made of (A) Bronze (B) Stainless steel (C) Flint or porcelain (D) Concrete

Last Answer : (C) Flint or porcelain

Work index is the gross energy (kWh/tonne of feed) necessary to reduce a very large feed to such a size that 80% of product particles will pass through a 0.1 mm screen. The value of work index determined for wet grinding should be multiplied with __________ to get the same for dry grinding. (A) 1.0 (B) 0.5 (C) 1.34 (D) 4.34

Description : Work index is the gross energy (kWh/tonne of feed) necessary to reduce a very large feed to such a size that 80% of product particles will pass through a 0.1 mm screen. The value of work index determined for wet grinding should ... to get the same for dry grinding. (A) 1.0 (B) 0.5 (C) 1.34 (D) 4.34

Last Answer : (C) 1.34

Which of the following size reduction equipments employs mainly attrition for ultrafine grinding? (A) Jet mills (B) Fluid energy mill (C) Micronizer (D) All (A), (B) and (C)

Description : Which of the following size reduction equipments employs mainly attrition for ultrafine grinding? (A) Jet mills (B) Fluid energy mill (C) Micronizer (D) All (A), (B) and (C)

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

3. __________ mill is normally used for grinding of talc. (A) Tube (B) Compartment (C) Ring-roll (D) Pebble

Description : 3. __________ mill is normally used for grinding of talc. (A) Tube (B) Compartment (C) Ring-roll (D) Pebble

Last Answer : (A) Tube

A __________ mill is a revolving mill divided into two or more sections by perforated partitions in which preliminary grinding takes place at one end and the finishing grinding at the discharge end. (A) Compartment (B) Tube (C) Rod (D) Pebble

Description : A __________ mill is a revolving mill divided into two or more sections by perforated partitions in which preliminary grinding takes place at one end and the finishing grinding at the discharge end. (A) Compartment (B) Tube (C) Rod (D) Pebble

Last Answer : (A) Compartmen

__________ mill is not used for grinding wheat into flour and for milling of cereals & other vegetable products. (A) Buhrstone (B) Roller (C) Attrition (D) Pebble

Description : __________ mill is not used for grinding wheat into flour and for milling of cereals & other vegetable products. (A) Buhrstone (B) Roller (C) Attrition (D) Pebble

Last Answer : (D) Pebble

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

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

In case of a hammer crusher, the final product size depends on the (A) Feed rate (B) Rotor speed(C) Clearance between hammer & grinding plates(D) All (A), (B) and (C

Description : In case of a hammer crusher, the final product size depends on the (A) Feed rate (B) Rotor speed (C) Clearance between hammer & grinding plates (D) All (A), (B) and (C

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

Out of the following, the best material capable of withstanding shock & vibration without the danger of cracking is (A) Malleable iron (B) Grey cast iron (C) Chilled cast iron (D) White cast iron

Description : Out of the following, the best material capable of withstanding shock & vibration without the danger of cracking is (A) Malleable iron (B) Grey cast iron (C) Chilled cast iron (D) White cast iron

Last Answer : Option A

Rod mills employed for grinding (A) Employ a steel shell having L/D ratio of 1.5 to 3.0 (B) Is useful for handling sticky materials (C) Employ steel rods of 2-12 cms diameter extending over full length of the mill (D) All 'a', 'b' & 'c'

Description : Rod mills employed for grinding (A) Employ a steel shell having L/D ratio of 1.5 to 3.0 (B) Is useful for handling sticky materials (C) Employ steel rods of 2-12 cms diameter extending over full length of the mill (D) All 'a', 'b' & 'c'

Last Answer : (D) All 'a', 'b' & 'c'

In case of a revolving mill, wet grinding compared to dry grinding (A) Requires more energy (B) Has less capacity (C) Complicates handling & classification of the product (D) None of these

Description : In case of a revolving mill, wet grinding compared to dry grinding (A) Requires more energy (B) Has less capacity (C) Complicates handling & classification of the product (D) None of these

Last Answer : (D) None of these

A fluid energy mill is used for (A) Cutting (B) Grinding (C) Ultra-grinding (D) Crushing

Description : A fluid energy mill is used for (A) Cutting (B) Grinding (C) Ultra-grinding (D) Crushing

Last Answer : (C) Ultra-grinding

A fluid energy mill is used for (A) Cutting (B) Grinding (C) Ultra grinding (D) Crushing

Description : A fluid energy mill is used for (A) Cutting (B) Grinding (C) Ultra grinding (D) Crushing

Last Answer : (C) Ultra grinding

Pick out the wrong statement. (A) Gape is the greatest distance between the crushing surfaces or the jaws (B) The angle of nip (2α) is the angle between roll faces at the level where they will just take hold of a particle and draw it in the crushing zone (C) Crushing efficiency is the ratio of the energy absorbed by the solid to the surfaces energy created by crushing (D) Reduction ratio is the ratio of the maximum size of the particles in the feed to that in the product

Description : Pick out the wrong statement. (A) Gape is the greatest distance between the crushing surfaces or the jaws (B) The angle of nip (2α) is the angle between roll faces at the level where they will ... Reduction ratio is the ratio of the maximum size of the particles in the feed to that in the product

Last Answer : (C) Crushing efficiency is the ratio of the energy absorbed by the solid to the surfaces energy created by crushing

Arrange the following size reduction equipment in the decreasing order of the average particle size produced by each of them. (A) Jaw crusher, Ball mill, Fluid energy mill(B) Ball mill, Jaw crusher, Fluid energy mill(C) Fluid energy mill, Jaw crusher, Ball mill(D) Fluid energy mill, Ball mill, Jaw crusher

Description : Arrange the following size reduction equipment in the decreasing order of the average particle size produced by each of them. (A) Jaw crusher, Ball mill, Fluid energy mill (B) Ball mill, Jaw crusher, Fluid ... C) Fluid energy mill, Jaw crusher, Ball mill (D) Fluid energy mill, Ball mill, Jaw crusher

Last Answer : (A) Jaw crusher, Ball mill, Fluid energy mill

Coal is finally pulverised to 200 mesh size for burning in boilers by a (A) Hammer crusher(B) Ball mill(C) Roll crusher(D) Gyratory crusher

Description : Coal is finally pulverised to 200 mesh size for burning in boilers by a (A) Hammer crusher (B) Ball mill (C) Roll crusher (D) Gyratory crusher

Last Answer : (B) Ball mill

Cement clinker is reduced to fine size by a (A) Roll crusher (B) Ball mill (C) Tube mill (D) Hammer mill

Description : Cement clinker is reduced to fine size by a (A) Roll crusher (B) Ball mill (C) Tube mill (D) Hammer mill

Last Answer : (C) Tube mill

A cylindrical rod of iron whose height is eight times its radius is melted and cast into spherical balls each of half the radius of the cylinder. -Maths 9th

Description : A cylindrical rod of iron whose height is eight times its radius is melted and cast into spherical balls each of half the radius of the cylinder. -Maths 9th

Last Answer : Let radius of iron rod = r ∴∴ Height = 8r ∴∴ Volume of iron rod =π×(r)2×8r⇒8πr3=π×(r)2×8r⇒8πr3 ⇒⇒ Radius of spherical ball =r2=r2 Volume of spherical ball =43π(r2)3=43π(r2)3 Let n balls are casted ∴n×43π(r38)=8πr3∴n×43π(r38)=8πr3 ⇒n6=8⇒n=48

A cylindrical rod of iron whose radius is one-fourth of its height is melted and cast into spherical balls of the same radius as that of the cylinder. -Maths 9th

Description : A cylindrical rod of iron whose radius is one-fourth of its height is melted and cast into spherical balls of the same radius as that of the cylinder. -Maths 9th

Last Answer : Let radius of cylindrical rod =r ⇒ height =4r Volume of cylindrical rod =πr2h =πr2(4r) =4πr3 Volume of spherical balls of radius r=34​πr3 No. of balls =34​πr34πr3​=

In which of the following cases, kinetic energy is being used in performing work? (1) Paddling the bicycle to cover a distance (2) Driving a car to cover a distance (3) Wind mill grinding wheat grain (4) Rowing a boat in the lake

Description : In which of the following cases, kinetic energy is being used in performing work? (1) Paddling the bicycle to cover a distance (2) Driving a car to cover a distance (3) Wind mill grinding wheat grain (4) Rowing a boat in the lake

Last Answer : (2) Driving a car to cover a distance Explanation: The work done on any object goes into changing the kinetic energy of that object. Since the work done by the car engine is equal to the change in ... defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.

In which of the following cases, kinetic energy is being used in performing work ? (1) Paddling the bicycle to cover a distance (2) Driving a car to cover a distance (3) Wind mill grinding wheat grain (4) Rowing a boat in the lake

Description : In which of the following cases, kinetic energy is being used in performing work ? (1) Paddling the bicycle to cover a distance (2) Driving a car to cover a distance (3) Wind mill grinding wheat grain (4) Rowing a boat in the lake

Last Answer : Driving a car to cover a distance

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

Description : 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

Last Answer : (B) Hammer crusher