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
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
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)
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)
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
Description : Pick out the wrong statement. (A) For the compressible cake, voidage & the specific resistance of the cake can be assumed to be constant (B) Cake resistance is independent of the pressure ... Crushing of explosive materials are done by employing dry-grinding (D) Gyratory crusher is a coarse crusher
Last Answer : (B) Cake resistance is independent of the pressure drop
Description : A fluid energy mill is used for (A) Cutting (B) Grinding (C) Ultra-grinding (D) Crushing
Last Answer : (C) Ultra-grinding
Description : A fluid energy mill is used for (A) Cutting (B) Grinding (C) Ultra grinding (D) Crushing
Last Answer : (C) Ultra grinding
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
Description : Which of the following crushing laws is most accurately applicable to the fine grinding of materials? (A) Bond's crushing law (B) Kick's law (C) Rittinger's law (D) None of these
Last Answer : (C) Rittinger's law
Description : Colloidal mills are used for __________ grinding. (A) Coarse (B) Intermediate (C) Fine (D) Ultrafine
Last Answer : (D) Ultrafine
Description : Gravity stamp mill is meant for the __________ crushing. (A) Primary (B) Intermediate (C) Fine (D) Ultrafine
Last Answer : (C) Fine
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)
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)
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 : 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 : 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)
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 : 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
Description : For coarse reduction of hard solids, use (A) Impact (B) Attrition (C) Compression (D) Cutting
Last Answer : (C) Compression
Description : The grinding in a hammer crusher takes place due to the (A) Attrition (B) Impact (C) Both (A) & (B) (D) Neither (A) nor (B
Description : Los Angeles testing machine is used to conduct (A) Abrasion test (B) Impact test (C) Attrition test (D) Crushing strength test
Last Answer : Answer: Option A
Description : Pick up the correct statement from the following: (A) Acid test is done to find out the weathering quality of stones (B) Attrition test is done to find out the rate of wear of stones which are used ... (C) Crushing test is done to find out the compressive strength of the stone (D) All the above
Last Answer : Answer: Option D
Description : Maximum size reduction in a fluid energy mill is achieved by (A) Compression (B) Interparticle attrition (C) Cutting (D) Impact
Last Answer : (B) Interparticle attrition
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 : Pick out the wrong statement. (A) Recycled coarse material to the grinder by a classifier is termed as circulating load (B) Wear and tear in wet crushing is more than that in dry crushing of ... a pipeline which permits the solids to settle down due to reduction in velocity of the dust laden gas
Last Answer : (C) Size enlargement (opposite of size reduction) is not a mechanical operation
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 : Explain the working, advantages and disadvantages of any one mill based on the principle of combined impact and attrition?
Last Answer : which of the following mill works on the principle of combined impact and attrition
Description : General mechanism of size reduction in intermediate and fine grinder is by (A) Cutting action (B) Compression (C) Compression and tearing (D) Impact and attrition
Last Answer : (D) Impact and attrition
Description : Crushing of mineral particles is accomplished in a 'cage mill', when one or more alloy steel bars are revolved in opposite directions. It is a type of __________ mill. (A) Impact (B) Roll (C) Vibratory (D) None of these
Last Answer : (A) Impact
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 : 3. __________ mill is normally used for grinding of talc. (A) Tube (B) Compartment (C) Ring-roll (D) Pebble
Last Answer : (A) Tube
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
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 : 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
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'
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 : 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
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.
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
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
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 : 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)