S9

Question 1

Sphericity of raschig ring (whose length and diameter are equal) is

Answer 1

1

Question 1

Chance process is used for the

Answer 1

cleaning of coal.

Question 2

Mixing mechanism employed in a pan mixer is by

Answer 2

mulling

Question 3

Which of the following screens has the maximum capacity?

Answer 3

Vibrating screen

Question 4

Stamp mills are generally used for crushing

Answer 4

gold ores

Question 5

In case of a plate and frame filter press, filtrate flow through the cake follows __________ flow.

Answer 5

laminar

Question 6

Which of the following is a batch sedimentation equipment?

Answer 6

Filter thickener

Question 7

The most suitable equipment for the transportation of 200 mesh size particles is a

Answer 7

pneumatic conveyor

Question 8

Which of the following is not used as filter aid?

Answer 8

Rice husk

Question 9

Raw materials are charged in the iron blast furnace using

Answer 9

skip hoist

Question 10

Carbon black is pulverised in a

Answer 10

ball mill

Question 11

The most efficient equipment for the removal of sub-micronic dust particles from blast furnace gas is the

Answer 11

electro-static precipitator

Question 12

The filtrate flow rate in constant pressure filtration

Answer 12

continuously decreases.

Question 13

Theoretical capacity of crushing rolls in tons/hr is given by (where,V= peripherial velocity, m/sec.W= width of rolls, mDr= distance between rolls ρ = density of material to be crushed, kg/m3here,V= πN.Dwhere,N= speed of the rolls in rotation per second (rps)D= diameter of rolls, m)

Answer 13

3.6V.W.Dr.ρ

Question 14

Vibrating screens are used for handling large tonnages of materials. The vibrating motion is imparted to the screening surface by means of

Answer 14

either (a), (b) or (c).

Question 15

The inlet pressure in a constant rate filtration

Answer 15

increases continuously

Question 16

Particle size range in which dust catcher (gravity settling chamber) works most effectively and efficiently is __________ microns.

Answer 16

< 74

Question 17

__________ centrifuge is the most suitable for separation of non-friable crystals.

Answer 17

Perforated horizontal basket continuous

Question 18

For benefication of iron ore, the most commonly used method is

Answer 18

jigging & tabling.

Question 19

A propeller agitator

Answer 19

produces mainly axial flow.

Question 20

In a grinding operation, the limiting particle size is the size of the __________ particle in the sample.

Answer 20

neither (a) nor (b)

Question 21

Screen capacity is proportional to (where,S= screen aperture)

Answer 21

S

Question 22

In coal washeries, three products namely the valuable product (i.e. clean/washed coal), discarded product (i.e. mineral matter) and an additional concentrated product called __________ is produced.

Answer 22

middling

Question 23

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?

Answer 23

Dry grinding of large particles in un-baffed mills.

Question 24

A __________ employs a set of screen across a flow channel for the separation of dirt/rust from a flowing liquid stream.

Answer 24

strainer

Question 25

Separation of a suspension or slurry into a supernatant clear liquid (free from particles) and a thick sludge containing a high concentration of solid is called

Answer 25

sedimentation

Question 26

Reciprocal of sphericity is termed as the

Answer 26

shape factor

Question 27

With increase in the pressure drop across the cake, the specific cake resistance for the compressible sludge

Answer 27

increases

Question 28

Pick out the wrong statement.

Answer 28

200 mesh screen has 200 openings per linear cm.

Question 29

Size reduction of ice and gypsum can be accomplished suitably by a __________ crusher.

Answer 29

toothed roll

Question 30

A filter press is

Answer 30

a batch filter.

Question 31

Xanthates are used in the froth floatation process as a/an

Answer 31

collector

Question 32

The ratio of the actual mesh dimension of Taylor series to that of the next smaller screen is

Answer 32

sqrt 2

Question 33

The ratio of the actual mesh dimension of Taylor series to that of the next smaller screen is

Answer 33

6 . V / D . S

Question 34

Limestone is normally crushed in a

Answer 34

hammer crusher

Question 35

Filtrate flow rate in case of a rotary drum vacuum filter (in which Rm < < Rc) is proportional to __________ and the cycle time (where, μ = filtrate viscosity Rm = filter medium resistance Rc = cake resistance).

Answer 35

1/ sqrt μ

Question 36

The main differentiation factor between tube mill and ball mill is the

Answer 36

length to diameter ratio.

Question 37

Introduction of slurry in a plate and frame filter press is done through a plate in each frame. The plate of this filter has a __________ surface.

Answer 37

ribbed

Question 38

Use of grinding aids results in the

Answer 38

neither (a) nor (b).

Question 39

A belt conveyor used for the transportation of materials can

Answer 39

all (a), (b) and (c).

Question 40

Which of the following is not used as a surface active agent in a flocculation operation?

Answer 40

Quartz

Question 41

__________ mill is not a revolving mill.

Answer 41

Cage

Question 42

For the transportation of ultrafine particles, the equipment used is a........conveyor.

Answer 42

pneumatic

Question 43

During filtration operation, the filtrate encounters the resistance of the

Answer 43

all (a), (b) and (c)

Question 44

Filtration rate does not depend upon the

Answer 44

none of these.

Question 45

Which of the following is a fine crusher?

Answer 45

Toothed roll crusher

Question 46

__________ is a cohesive solid.

Answer 46

Wet clay

Question 47

The optimum moisture content in solids to be crushed/ground ranges from __________ percent.

Answer 47

3 to 4

Question 48

The capacity of a gyratory crusher is __________ that of a jaw crusher with the same gape, handling the same feed & for the same product size range.

Answer 48

2.5 times

Question 49

Dispersion of a gas through liquid is done by using a

Answer 49

sparger

Question 50

Work index is defined as the

Answer 50

gross energy (kWh/ton of feed) needed to reduce very large feed to such a size that 80% of the product passes through a 100 micron screen.

Question 51

Removal of activated carbon from glycerine is done by

Answer 51

plate and frame filter

Question 52

What is the reduction ratio in a fine crushing operation having following feed and product sizes? Parameter Unit Maximum Minimum Feed Size mm 20 10 Product Size mm 10 5

Answer 52

2