me op 3

Question 1

Maximum size reduction in a fluid energy mill is achieved by
A. compression
B. interparticle attrition
C. cutting
D. impact

Answer 1

B

Question 2

Filtration rate through a filter cake is proportional to (where, S =
filtering surface R = specific cake resistance µ = viscosity of the
filtrate)
A. S
B. 1/R
C. 1/ µ
D. All

Answer 2

D

Question 3

A centrifugal filtration unit operating at aa rotational speed of w
has inner surface of the liquid (density 𝜌L) located at a radial
distance R from the axis of rotation. The thickness of the liquid
film is 𝛿 and no cake is formed. The initial pressure drop during
filtration is
A. 1/2𝑤^2 ∙𝑅^2 ∙𝜌𝐿
B. 1/2𝑤^2 ∙𝛿^2 ∙𝜌𝐿
C. 1/2𝑤^2 ∙𝛿𝜌𝐿∙(2𝑅+𝛿)
D. 1/2𝑤^2 ∙𝑅∙𝜌𝐿(𝑅+2𝛿)

Answer 3

D

Question 4

Which one is a filter aid?
A. Canvas fabric
B. Diatomaceous earth
C. Calcined lime
D. None of these

Answer 4

B

Question 5

To remove dirt from the flowing fluid, we use a
A. coagulant
B. gravity settler
C. strains
D. clarifier

Answer 5

C

Question 6

Which of the following crushers can be considered as a
combination of a jaw crusher and a roller crusher?
A. Rod mill
B. Fluid energy mill
C. Gyratory crusher
D. Ball mill

Answer 6

C

Question 7

Separation of solid suspended in liquid into a supernatant clear
liquid and a denser slurry employs a process termed
A. coagulation
B. flocculation
C. sedimentation
D. clarification

Answer 7

C

Question 8

Ultrafine grinders operate principally by
A. slow compression
B. impact
C. attrition
D. cutting action

Answer 8

C

Question 9

Which of the following comes in the category of primary crusher
for hard and tough stone?
A. Jaw crusher
B. Cone crusher
C. Gyratory crusher
D. None of these

Answer 9

A

Question 10

Crushing efficiency of a machine ranges between _______
percent.
A. 0.1 to 2
B. 5 to 10
C. 20 to 25
D. 50 to 70

Answer 10

A

Question 11

Screen capacity is expressed in terms of
A. tons/hr
B. tons/ft2
C. both a & b
D. tons/hr- ft2

Answer 11

D

Question 12

A screen is said to be blinded, when the
A. oversizes are present in undersize fraction.
B. undersizes are retained in oversize fraction.
C. screen is plugged with solid particles.
D. screen capacity is abruptly increased.

Answer 12

C

Question 13

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 ?

0.5
1.0
2.76
0.66

Answer 13

D

Question 14

Percentage of drum submerged in the slurry in case of rotary
drum filter is
A. 3
B. 30
C. 85
D. 25

Answer 14

B

Question 15

Filter medium resistance is that offered by the
A. filter cloth
B. embedded particles in the septum
C. filter cloth and the embedded particle collectively
D. none of these

Answer 15

C

Question 16

In a roll crusher, both the rolls
A. have the same diameter.
B. are rotated towards each other.
C. run either at the same or different speeds.
D. all

Answer 16

C

Question 17

Critical speed rotation, N (in rps – rotation per second) of a
trammel is equal to (where, g = acceleration due to gravity = 9.81
m/sec2 and, r = radius of trammel, metre).
A. 1/2n sqrt(g/r)
B. 1/n sqrt(g/r)
C.1/2 sqrt(g/r)
D. 2𝑛∙ sqrt(g/r)

Answer 17

A

Question 18

Activators are those chemicals which help buoying up one
mineral in preference to the other in the froth floatation process.
Which of the following is an activator?
A. Cresylic acid
B. Copper sulphate
C. Calcium carbonate
D. Sodium carbonate

Answer 18

B

Question 19

For the preliminary breaking of hard rock, we use
A. gyratory crusher
B. ball mill
C. tube mill
D. squirrel-cage disintegrator

Answer 19

A

Question 20

Filtration operation carried out by continuous increase of the
inlet pressure of slurry, is called ________ filtration.
A. constant rate
B. varying pressure
C. varying rate
D. constant pressure

Answer 20

A

Question 21

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 drop.
C. Crushing of explosive materials are do

Answer 21

B

Question 22

Which of the following oxides is not present in hematite iron ore?
A. Titanium oxide
B. Calcium oxide
C. Cobalt oxide
D. Manganese oxide

Answer 22

C

Question 23

Ribbon blenders are exclusively meant for
A. blending miscible liquids.
B. non-flowing powder and thin pastes.
C. bath mixing.
D. continuous mixing.

Answer 23

B

Question 24

In closed circuit grinding as compared to open circuit grinding,
the
A. specific surface of product is more.
B. product has lesser size uniformity.
C. production rate at a given limiting size is lower.
D. operation is economical.

Answer 24

D

Question 25

Tube mill compared to ball mill A. produces finer products. B. is long in comparison with its diameter. C. uses smaller balls. D. all

Answer 25

D

Question 26

Gelatinous solid (which plug the septum) can be filtered by a ______ filter. A. Sparkler B. plat and frame C. vacuum leaf D. precoat

Answer 26

D

Question 27

During the washing of cake A. all the resistance are constant. B. filter medium resistance increases. C. filter medium resistance decreases. D. cake resistance decreases.

Answer 27

D

Question 28

The opening of a 200 mesh screen (Taylor series) is A. 0.0074 cm B. 0.0074 mm C. 0.0047 cm D. 74 milli-microns

Answer 28

A

Question 29

A gravity decanter is meant for the separation of two _______ density. A. immiscible liquids of different B. miscible liquids of different C. immiscible liquids of same D. miscible liquids of same

Answer 29

A

Question 30

The most suitable filter for the removal of very small amount of precipitate from very large volumes of water is the _______ filter. A. vacuum B. sand C. plate & frame D. rotary

Answer 30

B

Question 31

Pick out the correct statement. A. Angle of repose is always greater than the angle of slide. B. A hopper is a small bin with a sloping bottom. C. A silo is a short height vessel of very large diameter used for the storage of high volatile matter coal. D. Pine oil is used as a ‘modifying agent’ (for activating or depressing the adsorption of filming agents? In froth floatation process.

Answer 31

B

Question 32

Separation of solid particles based on their densities is called A. sizing B. sorting C. clarification D. dispersion

Answer 32

B

Question 33

______ are mixed using ribbon blenders. A. Lumpy solids and low viscosity liquids B. Dry powders C. High viscosity liquids D. Thick pastes

Answer 33

B

Question 34

During agitation of liquids, the A. Froude number is independent for the curves between power number and Reynolds number in baffled system. B. Power number becomes independent of impellers Reynolds number at high Reynolds number, but is dependent on the geometry of the impeller. C. Froude number is used to account for the effect surface (e.g., the centre vortex) on the power number. D. All

Answer 34

D

Question 35

For crushing of solids, the Rittinger’s law states that the work required for crushing is proportional to A. the new surface created. B. the size reduction ratio. C. the change in volume due to crushing. D. none of these

Answer 35

A

Question 36

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

Answer 36

C

Question 37

Pick out the wrong statement. A. More commonly used jaw crusher between Dodge jaw crusher and Blake jaw crusher is the latter one. B. There are only four methods namely compression, impact, attrition and cutting, which the size reduction equipment employ. C. Cutting machines mainly employ ‘attrition’ for size reduction of solids. D. Operating principles of Dodge and Blake jaw crushers are combined in the working of universal jaw crushers.

Answer 37

C

Question 38

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

Answer 38

B

Question 39

As per Taggart’s formula, the capacity (kg/hr) of Jaw & Gyratory crushers (for gapes of 10 to 60 cm) is equal to (where, L = length of feed opening, cm S = Max width of discharge opening, cm). A. LS B. 93 LS C. 250 LS D. √𝐿S

Answer 39

B

Question 40

The process by which fine solids is removed from liquids is termed as A. decantation B. flocculation C. sedimentation D. classification

Answer 40

C

Question 41

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

Answer 41

C

Question 42

Shell and leaf filter as compared to plate and frame filter A. entails less labor cost. B. facilitates filtration under higher pressure. C. provides more effective washing. D. all

Answer 42

D

Question 43

Metallic wire mesh is used as a filtering medium for the separation of dust from dust laden gas in case of a/an A. air filter B. bag filter C. venturi scrubber D. hydrocyclones

Answer 43

A

Question 44

Which of the following is a course crusher? A. Smooth roll crusher B. Toothed roll crusher C. Gyratory crusher D. Tube mill

Answer 44

C

Question 45

Sorting classifiers employing differential settling methods for separation of particles make use of the differences in their A. particle sizes B. densities C. terminal velocities D. none of these

Answer 45

C

Question 46

Separation of particles of various sizes, shapes, and densities by allowing them to settle in a fluid is called A. classification B. froth flotation C. thickening D. clarification

Answer 46

A

Question 47

The specific cake resistance for incompressible sludges is (where ∆𝑃 = pressure drop over cake) A. ∝∆𝑃 B. ∝1/∆𝑃 C. ∝√∆𝑃 D. Independent of ∆𝑃

Answer 47

D

Question 48

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

Answer 48

C

Question 49

To produce talcum powder, use A. ball mill B. hammer mill C. jet mill D. pin mill

Answer 49

A

Question 50

Angle nip of the crushing rolls does not depend upon the A. diameter of the rolls B. speed of the rolls C. product size D. feed size

Answer 50

B

Question 51

Paddle agitator A. is suitable for mixing low viscosity liquids. B. produces axial flow. C. moves at very high speed. D. none of these

Answer 51

A

Question 52

Gummy & sticky materials like molasses, sugar etc. are best transported/handled by using a ______ conveyor. A. Drag B. Ribbon C. Screw D. Slat

Answer 52

B

Question 53

Soft & non-abrasive materials can be made into fines by A. attrition B. compression C. cutting D. none of these

Answer 53

A

Question 54

In constant pressure filtration, A. resistance decreases with time B. rate of filtration is constant C. rate of filtration increases with time D. rate of filtration decreases with time

Answer 54

D

Question 55

The critical speed of a trommel (N) is related to its diameter (D) as A. 𝑁∝ 1/√D B. 𝑁∝√𝐷 C. 𝑁∝𝐷 D. 𝑁∝ 1/D

Answer 55

A

Question 56

Which of the following minerals is not subjected to magnetic separation method? A. Rutile B. Galena C. Chromite D. Siderite

Answer 56

B

Question 57

Which of the following is not a revolving/tumbling mill used for size reduction? A. Compartment mill B. Pebble mill C. Cage mill D. Rod mill

Answer 57

C

Question 58

Which of the following achieves the least reduction ratio for a given feed size? A. Jaw crusher B. Roll crusher C. Cone crusher D. Gyratory crusher

Answer 58

B

Question 59

A fluid energy mill is used for A. cutting B. grinding C. ultragrinding D. crushing

Answer 59

C

Question 60

Filtration should be stopped in a filter press, if the A. cake becomes very dense. B. liquor stops flowing out to the discharge. C. filtration pressure rises suddenly. D. both b & c

Answer 60

D

Question 61

For coarse reduction of hard solids, use A. impact B. attrition C. compression D. cutting

Answer 61

C

Question 62

Traces of liquid tar fog present in coke oven gas is separated is separated using A. electrostatic precipitator B. cyclone separator C. strainer D. none of these

Answer 62

A

Question 63

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

Answer 63

C

Question 64

Choke crushing (in case of a Jaw crusher) compared to free crushing A. results in increased capacity. B. consumes less power. C. consumes more power. D. both a and c

Answer 64

C

Question 65

The specific surface of spherical particles is proportional to (where, Dp = diameter of particle). A. 𝐷^2 p B. 𝐷p C. 1/𝐷p D. 1/𝐷^2 p

Answer 65

C

Question 66

Wheat is ground into flour in a A. hammer crusher B. roller crusher C. impact mill D. fluid energy mill

Answer 66

B

Question 67

Gravity stamp mill is meant for the _____ crushing. A. primary B. intermediate C. fine D. ultrafinE

Answer 67

C

Question 68

Washability curve based on float and sink test enables an assessment to be made of the possibility of cleaning a coal fraction based on the A. density separation B. differential wettability C. size D. volatile matter content

Answer 68

A

Question 69

Toothed roll crushers achieve size reduction by A. tearing (shear) and compression B. impact and attrition C. both a & b D. neither a nor b

Answer 69

C

Question 70

To get ultrafine particles, the equipment used is a A. ball mill B. rod mill C. hammer crusher D. fluid energy mill

Answer 70

D

Question 71

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 size to the maximum product size. C. Gyratory crusher is used for coarse crushing. D. Screens are of stationary, moving and vibratory types.

Answer 71

B

Question 72

Vacuum filter is most suitable for the A. removal of fines from liquid. B. liquids having high vapor pressure. C. liquids of very high viscosity. D. none of these

Answer 72

D

Question 73

The porosity of a compressible cake is A. minimum at the filter medium. B. minimum at the upstream face. C. maximum at the filter medium. D. same throughout the thickness of cake.

Answer 73

A

Question 74

Which of the following conveyors cannot be recommended for transport of abrasive materials? A. Belt conveyor B. Apron conveyor C. Flight conveyor D. Chain conveyor

Answer 74

C

Question 75

Separation of materials into products based on the difference of their sizes is called A. sizing B. sorting C. classification D. flocculation

Answer 75

A

Question 76

for classification of potable (drinking) water, we use a ______ filter. A. gravity sand B. plate and frame C. vacuum leaf D. rotary vacuum

Answer 76

A

Question 77

Hot, lumpy & abrasive materials are best transported by using a/an _______ conveyor. A. apron B. blet C. screw D. flight

Answer 77

A

Question 78

Additives used for promoting the flocculation of particles is a/an A. electrolyte B. surface active agent C. both a & b D. neither a nor b

Answer 78

C

Question 79

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 product. D. all

Answer 79

D

Question 80

The capacity of a classifier in ‘tons of solid/hr’ is given by (where, A = cross sectional area, m2 V = rising velocity of fluid, m/sec S = percentage of solids in the suspension by volume, ρ = density of solids, kg/m3) A. 3.6 AVS. ρ B. 3.6 A.V. ρ C. 3.6 A.S. ρ D. 3.6 AVS/ ρ

Answer 80

A

Question 81

Kick’s law relates to A. energy consumption B. final particle size C. feed size D. none of these

Answer 81

A

Question 82

________ mill is normally used for grinding of talc. A. tube B. compartment C. ring-roll D. pebble

Answer 82

C

Question 83

Colloidal mills are used for _______ grinding. A. coarse B. intermediate C. fine D. ultrafine

Answer 83

D

Question 84

Fluid medium used in the classification technique of mineral beneficiation is A. air B. water C. both a & b D. neither a nor b

Answer 84

C

Question 85

The maximum slope pf a belt conveyor can be A. 15° B. 30° C. 45° D. 60°

Answer 85

B

Question 86

The filter medium resistance is controlled by A. pressure drop alone B. flow rate alone C. both pressure drop and flow rate D. cake thickness

Answer 86

C

Question 87

The unit of filter medium resistance is A. cm-1 B. gm/ cm-1 C. cm/ gm-1 D. gm-1

Answer 87

A

Question 88

During size reduction by a jaw crusher, the energy consumed decreases with the A. decreasing size of product at constant size of feed. B. decreasing machine capacity. C. increasing size of feed at constant reduction ratio. D. none of these

Answer 88

C

Question 89

Which of the following can be most effectively used for clarification of lube oil and printing ink? A. Sparkler filter B. Precoat filter C. Disc-bowl centrifuge D. Sharpies supercentrifuge

Answer 89

D

Question 90

Ultracentrifuges running at speeds upto 100000 rpm is normally used for the A. separation of isotopes based on their density or molecular weights difference. B. concentration of rubber latex. C. separation of cream from milk. D. dewaxing of lubricating oil.

Answer 90

A

Question 91

Sizing of very fine particles of the order of 5 to 10 microns is done by elutriation, which is a _______ operation A. clarification B. sedimentation C. flocculation D. classification

Answer 91

D

Question 92

In the cyclone separator used for separation of dust from laden gas, the gas A. enters the cyclone from the top. B. is admitted tangentially at high velocity. C. develops a helical motion inside the chamber. D. both b & c

Answer 92

D

Question 93

The basic filtration equation is given as__ where, V is volume of the filtrate; A is the filtration area, a is specific cake resistance, u is viscosity of the filtrate, and C is the concentration of the solids in the feed slurry. In a 20 minutes constant rate filtration, 5 m3 of the filtrate was obtained. If this is followed by a constant pressure filtration, how much more time in minutes, it will take for another 5 m3 of filtrate to be produced? Neglect filter medium resistance, RM; assume incompressible cake. A. 10 B. 20 C. 25 D. 30

Answer 93

B

Question 94

Size reduction of fibrous materials like wood, asbestos, mica etc. is done by a disintegrator exemplified by the A. Blake jaw crusher B. cage mill C. stamp mill D. Bradford’s breaker

Answer 94

B

Question 95

The material is crushed in a gyratory crusher by the action of A. impact B. compression C. attrition D. cutting

Answer 95

B

Question 96

The equivalent diameter of channel of a constant non-circular cross section of 3 cm by 6 cm will be ________ cm. A. 20 B. 12 C. 8 D. 2

Answer 96

D

Question 97

Which of the following may prove unsuitable for filtering volatile liquids? A. Pressure filter B. Gravity filter C. Centrifugal filter D. Vacuum filter

Answer 97

D

Question 98

_______ mean diameter of particles is given by ∑𝑥/𝐷⃗ A. Mass B. Volume C. Arithmetic D. Volume surface

Answer 98

B

Question 99

Sauter mean diameter is the same as the _____ mean diameter A. mass B. arithmetic C. volume surface D. geometric

Answer 99

C

Question 100

Cake resistance is A. important in the beginning of filtration. B. decreased with the time of filtration. C. independent of pressure drop. D. none of these

Answer 100

D

Question 101

In paint industries, blending of light paste is done by using a A. masticator B. charge can mixer C. kneader D. none of these

Answer 101

B

Question 102

A sand mixture was screened through a standard 10-mesh screen. The mass fraction of the oversize material in feed, overflow and underflow were found to be 0.38, 0.79 and 0.22 respectively. The screen effectiveness based on the oversize is A. 0.50 B. 0.58 C. 0.68 D. 0.62

Answer 102

A

Question 103

_______ is used for producing a thick suspension from a thin slurry. A. Cartridge filter B. Rotary drum vacuum filter C. Pressure filter thickener D. Plate and frame filter press

Answer 103

C

Question 104

Wet sieving is employed, when the product contains ________ materials. A. abrasive B. large quantity of very fine C. coarse D. non-sticky

Answer 104

B

Question 105

Energy requirement (per unit mass of material crushed/ground) is highest for A. jaw crusher B. rod mill C. ball mill D. fluid energy mill

Answer 105

D

Question 106

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

Answer 106

D

Question 107

Energy consumption in a crusher decreases with increase in the A. size of the product (at constant feed size) B. capacity of the crushing machine C. size of feed (at constant reduction ratio) D. all

Answer 107

D

Question 108

In a mixer, the quantity, (v. L/D) is termed as _____ number (where, v = longitudinal velocity of material, L = length of the mixer, D = diffusivity in axial mixing). A. Weber B. Peclet C. Brinkman D. Schmidt

Answer 108

B

Question 109

Mass flow of granular solid (M) through a circular opening of dia, D follows A. 𝑀∝√𝐷 B. 𝑀∝𝐷^2 C. 𝑀∝𝐷^3 D. 𝑀∝𝐷

Answer 109

C

Question 110

The term ‘angle of nip’ is concerned with the operation of the _______ crushers. A. jaw B. roll C. gyratory D. none of these

Answer 110

B

Question 111

Cartridge filters are termed as ‘edge’ filters, because of the fact that the A. disks have very sharp edge. B. solids are not deposited at the edge of the disk. C. bulk of the solids are removed at the periphery of the disks. D. none of these

Answer 111

C

Question 112

Vibrating screens have capacity in range of ______ tons/ft2 mm mesh size. A. 0.2 to 0.8 B. 5 to 25 C. 50 to 100 D. 100 to 250

Answer 112

A

Question 113

Cumulative analysis for determining surface is more precise than differential analysis, because of the A. assumption that all particles in a single fraction are equal in size. B. fact that screening is more effective. C. assumption that all particles in a single fraction are equal in size, is not needed. D. none of these

Answer 113

C

Question 114

To remove very small amount of tiny solid impurities from liquid, we use a A. pressure filter B. vacuum filter C. centrifugal filter D. coagulant

Answer 114

D

Question 115

Screw conveyors are A. run at very high rpm B. suitable for sticky materials C. suitable for high abrasive materials D. all

Answer 115

B