S9 Flashcards
Sphericity of raschig ring (whose length and diameter are equal) is
1
Chance process is used for the
cleaning of coal.
Mixing mechanism employed in a pan mixer is by
mulling
Which of the following screens has the maximum capacity?
Vibrating screen
Stamp mills are generally used for crushing
gold ores
In case of a plate and frame filter press, filtrate flow through the cake follows __________ flow.
laminar
Which of the following is a batch sedimentation equipment?
Filter thickener
The most suitable equipment for the transportation of 200 mesh size particles is a
pneumatic conveyor
Which of the following is not used as filter aid?
Rice husk
Raw materials are charged in the iron blast furnace using
skip hoist
Carbon black is pulverised in a
ball mill
The most efficient equipment for the removal of sub-micronic dust particles from blast furnace gas is the
electro-static precipitator
The filtrate flow rate in constant pressure filtration
continuously decreases.
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)
3.6V.W.Dr.ρ
Vibrating screens are used for handling large tonnages of materials. The vibrating motion is imparted to the screening surface by means of
either (a), (b) or (c).
The inlet pressure in a constant rate filtration
increases continuously
Particle size range in which dust catcher (gravity settling chamber) works most effectively and efficiently is __________ microns.
< 74
__________ centrifuge is the most suitable for separation of non-friable crystals.
Perforated horizontal basket continuous
For benefication of iron ore, the most commonly used method is
jigging & tabling.
A propeller agitator
produces mainly axial flow.
In a grinding operation, the limiting particle size is the size of the __________ particle in the sample.
neither (a) nor (b)
Screen capacity is proportional to (where,S= screen aperture)
S
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.
middling
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?
Dry grinding of large particles in un-baffed mills.
A __________ employs a set of screen across a flow channel for the separation of dirt/rust from a flowing liquid stream.
strainer
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
sedimentation
Reciprocal of sphericity is termed as the
shape factor
With increase in the pressure drop across the cake, the specific cake resistance for the compressible sludge
increases
Pick out the wrong statement.
200 mesh screen has 200 openings per linear cm.
Size reduction of ice and gypsum can be accomplished suitably by a __________ crusher.
toothed roll
A filter press is
a batch filter.
Xanthates are used in the froth floatation process as a/an
collector
The ratio of the actual mesh dimension of Taylor series to that of the next smaller screen is
sqrt 2
The ratio of the actual mesh dimension of Taylor series to that of the next smaller screen is
6 . V / D . S
Limestone is normally crushed in a
hammer crusher
Filtrate flow rate in case of a rotary drum vacuum filter (in whichRm< <Rc) is proportional to __________ and the cycle time (where, μ = filtrate viscosityRm= filter medium resistanceRc= cake resistance).
1/ sqrt μ
The main differentiation factor between tube mill and ball mill is the
length to diameter ratio.
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.
ribbed
Use of grinding aids results in the
neither (a) nor (b).
A belt conveyor used for the transportation of materials can
all (a), (b) and (c).
Which of the following is not used as a surface active agent in a flocculation operation?
Quartz
__________ mill is not a revolving mill.
Cage
For the transportation of ultrafine particles, the equipment used is a……..conveyor.
pneumatic
During filtration operation, the filtrate encounters the resistance of the
all (a), (b) and (c)
Filtration rate does not depend upon the
none of these.
Which of the following is a fine crusher?
Toothed roll crusher
__________ is a cohesive solid.
Wet clay
The optimum moisture content in solids to be crushed/ground ranges from __________ percent.
3 to 4
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.
2.5 times
Dispersion of a gas through liquid is done by using a
sparger
Work index is defined as the
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.
Removal of activated carbon from glycerine is done by
plate and frame filter
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
2
