Free Fluid Flow Operations MCQs with Answers

• A. Plug
• B. Turbulent
• C. Laminar
• D. None of these

Explanation: Flow through the porous filter cake is described by Darcy’s law, which treats the cake as a porous medium with essentially laminar flow.

• A. Banbury
• B. Pug mill
• C. Pan
• D. Tumbling

Explanation: A tumbling mixer is a rotating vessel that mixes solids by repeated lifting and cascading, much like a ball mill operating without…

• A. As high as 100
• B. 10-20
• C. 20-40
• D. 5-10

Explanation: Fine grinders make a large size reduction in one stage, so their reduction ratio may reach about 100.

• A. Both B. & C.
• B. Liquor stops flowing out to the discharge
• C. Filtration pressure rises suddenly
• D. Cake becomes very dense

Explanation: A filter press should be stopped when filtrate discharge ceases or the pressure rises abnormally, since these indicate that the cake or…

• A. Conditioner
• B. Frother
• C. Collector
• D. Activator

Explanation: Xanthates adsorb preferentially on the surfaces of valuable mineral particles and make them hydrophobic, allowing them to attach to air…

• A. Slightly more than
• B. Much more than
• C. At least equal to
• D. Less than

Explanation: A ball mill is operated below its critical speed so that the balls are lifted and then fall or cascade through the material.

• A. None of these
• B. Resistance of the cake & the septum
• C. Properties of the cake & the filtrate
• D. Pressure drop & area of filtering surface

Explanation: Filtration rate depends on the pressure drop and area, the resistance of the cake and septum, and the properties of both cake and…

• A. 1.5
• B. 0.5
• C. 1.0
• D. 2.0

Explanation: For a cylinder whose length equals its diameter, the usual unit-operations shape-factor value is 1.5, reflecting its surface geometry…

• A. Dust catcher
• B. Dry cyclone separator
• C. Filter thickener
• D. Rotary sprayer scrubber

Explanation: A filter thickener is operated batchwise to settle solids and produce a concentrated underflow, unlike continuous devices such as dust…

• A. Solids
• B. Solids from solids
• C. Liquids
• D. Solids from fluids

Explanation: A cyclone uses centrifugal action to remove suspended solid particles from a gas or liquid stream.

• A. Cyclone separator
• B. Electrostatic precipitator
• C. Strainer
• D. None of these

Explanation: An electrostatic precipitator can remove very fine liquid droplets such as tar fog from coke-oven gas by electrically charging and…

• A. 2250
• B. 1125
• C. 460
• D. 230

Explanation: The cyclone separation factor is approximately v²/(gR), where R is the cyclone radius: 15²/(9.81 × 0.1) ≈ 230.

• A. Belt
• B. None of these
• C. Screw
• D. Pneumatic

Explanation: Pneumatic conveyors transport fine or ultrafine particles by suspending them in a moving gas stream.

• A. Used for small scale filtration work
• B. A continuous filter
• C. A high pressure filter
• D. A leaf filter

Explanation: A Nutsche filter is usually a batch filter used for relatively small-scale operations, often combining filtration and cake washing in one…

• A. Sedimentation
• B. Flocculation
• C. Filtration
• D. None of these

Explanation: Dispersion separates particles throughout a medium, whereas flocculation brings suspended particles together into loose aggregates.

• A. Its openings size
• B. Screening mechanism
• C. Atmospheric humidity
• D. Screening surface

Explanation: Screen capacity depends on opening size, the screening mechanism, and the available screening surface.

• A. Roll crusher
• B. Tube mill
• C. Ball mill
• D. Hammer crusher

Explanation: Limestone is relatively soft and is commonly reduced in size with impact equipment such as a hammer crusher.

• A. Both A. & B.
• B. Pressure
• C. Rate
• D. Neither A. nor B.

Explanation: Cake thickness and therefore cake resistance grow as filtration proceeds under constant-pressure operation.

• A. Decreases
• B. Increases
• C. Remain constant
• D. May increase or decrease; depends on the material being ground

Explanation: Most of the mechanical energy supplied during ultrafine grinding is ultimately converted into heat, so the product temperature generally…

• A. Hammer mill
• B. Ball mill
• C. Jet mill
• D. Pin mill

Explanation: Ball mills are commonly used to grind soft minerals such as talc into powder.