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

1 Answer

Answer :

(A) Coarse feed requires a larger ball

Related questions

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

Last Answer : (C) Fine grinding

Description : 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

Last Answer : (A) Less than

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

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

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 )

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

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)

Description : This type seed metering mechanism consist of wheel with fine and coarse ribbed flanges. b. fluted feed c. Cup feed d. None of the above

Last Answer : Ans - a. Internal double run

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

Description : To get a fine talc powder from its granules, the equipment used is (A) Roller crusher (B) Ball mill (C) Jaw crusher (D) Gyratory crusher

Last Answer : (B) Ball mill

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

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

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

Description : __________ 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

Last Answer : (B) Minimum size

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

Description : Combustion of pulverised fuel (A) Requires larger combustion chamber than rich gaseous fuel (B) In a metallurgical furnace does not contaminate the product in the furnace by ash from fuel (C) Suppresses the discharge of fine dust and grit into atmosphere (D) All (A), (B) and (C)

Last Answer : (A) Requires larger combustion chamber than rich gaseous fuel

Description : Pick out the wrong statement. (A) The integral method of analysing kinetic data is used when the data is scattered (B) The differential method of analysing kinetic data requires more accurate ... less than one for identical feed composition, flow rate, conversion and for all positive reaction orders

Last Answer : (C) When the reaction rate is independent of temperature, the reaction is said to be of zero order

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

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)

Description : Which of the following is a coarse crusher? (A) Smooth roll crusher (B) Toothed roll crusher (C) Gyratory crusher (D) Tube mill

Last Answer : (C) Gyratory crusher

Description : The optimum performance for reactors operating in parallel is obtained when the feed stream is distributed in such a way, that the (A) Space time for each parallel line is same (B) Space time for ... is different (C) Larger reactors have more space time compared to smaller ones (D) None of these

Last Answer : (A) Space time for each parallel line is same

Description : 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)

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

Description : Colloidal mills are used for __________ grinding. (A) Coarse (B) Intermediate (C) Fine (D) Ultrafine

Last Answer : (D) Ultrafine

Description : Ultra centrifuges are used for the separation of __________ solid particles. (A) Coarse (B) Fine (C) Colloidal (D) Dissolved

Last Answer : (C) Colloidal

Description : Wet sieving is employed, when the product contains __________ materials. (A) Abrasive (B) Large quantity of very fine (C) Coarse (D) Non-sticky

Last Answer : (B) Large quantity of very fine

Description : Grizzlies are used for separating __________ solids. (A) Coarse (B) Fine (C) Any size (D) None of these

Last Answer : (B) Fine

Description : __________ are used for the separation of coarse particles from a slurry of fine particles. (A) Thickeners (B) Classifiers (C) Hydrocyclones (D) Decanters

Last Answer : (B) Classifiers

Description : Pick out the wrong statement pertaining to leaching. (A) Fine solids cannot be leached in a Pachuca tank (B) Door classifier can be used for leaching of coarse solids (C) Vegetable seeds can be ... , Rotocel or Kennedy extractor (D) Very high temperature is not needed for the leaching of sugar beet

Last Answer : (A) Fine solids cannot be leached in a Pachuca tank

Description : __________ of austenite decreases the hardenability in steel. (A) Fine grains (B) Coarse grains (C) Homogeneity (D) Dissolved elements (except cobalt)

Last Answer : (D) Dissolved elements (except cobalt)

Description : In a size reduction crushing operation, the feed size is 10 to 50 mm, while the product size is 2 to 10 mm. This is a case of __________ crushing. (A) Primary (B) Secondary (C) Fine

Last Answer : (C) Fine

Description : In a size reduction crushing operation, feed size is 100 to 300 mm. while the product size is 10 to 50 mm. This is a case of the __________ crushing. (A) Primary (B) Secondary (C) Fine (D) Ultrafine

Last Answer : (B) Secondary

Description : In a size reduction crushing operation, feed size is 300 to 1500 mm while the product size is 100 to 300 mm. This is a case of the __________ crushing. (A) Secondary (B) Fine (C) Primary (D) Ultrafine

Last Answer : (C) Primary

Description : Tabular bowl centrifuges as compared to disk bowl centrifuges (A) Operate at higher speed (B) Employ bowl of larger diameter (C) Can’t be operated under pressure/vacuum (D) Can’t be used for separation of fine suspended solids from a liquid

Last Answer : (A) Operate at higher speed

Description : Pick up the correct statement from the following: (A) Bulking of sand is caused due to formation of a thin film of surface moisture (B) Fine sand bulks more than coarse sand (C) The volume of fully saturated sand, is equal to the volume of dry and loose sand (D) All the above

Last Answer : Answer: Option D

Description : Pick up the correct statement from the following: (A) Adding 5% to 6% of moisture content by weight, increases the volume of dry sand from 18% to 38% (B) The bulking of fine sand is ... the percentage content of moisture exceeds 10%, increase in bulk of sand starts increasing (D) All the above

Last Answer : Answer: Option D

Description : Which one of the following statements is correct? (a) Adding 5% to 6% of moisture by weight increases the volume of dry sand from 18% to 38% (b) The bulking of fine sand is more than that of coarse sand (c ) Volume of fully saturated sand is equal to that of dry sand (d) All of the above

Last Answer : (d) All of the above

Description : Pick out the wrong statement: (A) Magnetic separation method can be employed to treat both dry & wet ores (B) Reduction ratio in crushing operation is defined as the ratio of minimum feed ... ) Gyratory crusher is used for coarse crushing (D) Screens are of stationary, moving and vibratory types

Last Answer : (B) Reduction ratio in crushing operation is defined as the ratio of minimum feed size to the maximum product size

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

Description : Coarse threads have helix angle _____ fine threads. a) Equal to b) Greater than c) Lesser than d) There is no relation

Last Answer : c) Lesser than

Description : The static load carrying capacity of fine threads is greater than that of coarse threads. a) True b) False

Last Answer : b) False

Description : Internal friction between the ingredients of concrete, is decreased by using (A) Less water (B) Fine aggregates (C) Rich mix (D) More water and coarse aggregates

Last Answer : Answer: Option D

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

Description : Which type of threads is recommended for fluctuating loads? a) Fine threads b) Coarse Threads c) Either of fine or coarse d) None of the listed

Last Answer : a) Fine threads

Description : Which threads have greater resistance to unscrewing? a) Coarse b) Fine c) They have equal resistance d) Cannot be determined

Last Answer : b) Fine

Description : The designation M 36 × 2 means (A) Metric fine threads of 36 mm outside diameter and 2 mm pitch (B) Metric coarse threads of 36 mm outside diameter and 2 mm pitch (C) Metric threads of 36 mm pitch diameter and 2 mm pitch (D) Metric threads of 36 mm core diameter and 2 mm pitch

Last Answer : (A) Metric fine threads of 36 mm outside diameter and 2 mm pitch

Description : The strainer type tube well, is unsuitable for (A) Coarse gravels (B) Fine sandy strata (C) Clean gravels (D) None of these

Last Answer : (B) Fine sandy strata

Description : The soil which contains finest grain particles, is (A) Coarse sand (B) Fine sand (C) Silt (D) Clay

Last Answer : (D) Clay

Description : For better strength and stability, the fine grained soils and coarse grained soils are compacted respectively as (A) Dry of OMC and wet of OMC (B) Wet of OMC and dry of OMC (C) Wet of OMC and wet of OMC (D) Dry of OMC and dry of OMC where OMC is optimum moisture content

Last Answer : Answer: Option B

Description : Pick up the correct statement from the following: (A) The dry density reduces by addition of water after attaining optimum moisture content (B) The line joining the peak of three moisture content graphs ... be compacted to a very high density as compared to fine grained soils (D) All the above

Last Answer : Answer: Option D