Particle Technology Flashcards
Filter aid is used
To increase the porosity of the cake
The porosity of compressible cake is
Minimum at the filter medium
Which of the following may prove unsuitable for filtering volatile liquids?
A. Pressure filter
B. Centrifugal filter
C. Gravity filter
D. Vacuum filter
D. Vacuum filter
Increasing the capacity of screen
Decreases the screen effectiveness
Screen efficiency is
Recovery x rejection
As particle size is reduced
Screening becomes progressively more difficult
A screen is said to be blinded when
The screen is plugged with solid particles
The material passing one screen surface and retained on a subsequent surface is called
Intermediate material
In screen analysis, notation + 5mm/ -10 mm means passing through
10 mm screen and retained on 5 mm screen
Mesh number indicates the number of holes per
Linear inch
Sphericity of a cylinder whose length equals its diameter
0.87
Size measurement of ultrafine particles can be best expressed in terms of
Square area/ unit mass
Example of a hard material
Sapphire
For the preliminary breaking of hard rock, we use
Gyratory crusher
Size reduction mechanism used in jaw crushers is
Compression
To get ultrafine particles, the equipment used is
Fluid energy mill
Maximum size reduction in a ball mill is done by
Impact
The operating speed of a ball mill should be
Less than the critical speed
As the product becomes finer, the energy required for grinding
Increases
The operation by which solids are separated from liquids due to difference in the respective densities is
Sedimentation
Forces acting on a particle settling in fluid are
Gravitational, centrifugal, buoyant, drag forces
Drag is defined as the force exerted by the
Fluid on the solid in a direction opposite to flow
Stoke’s Law is valid when the particle Reynolds number is
1
The terminal velocity of a small sphere settling in a viscous fluid varies as the
Inverse of fluid viscosity
