Partech Flashcards
Increasing the capacity of screen causes ____
decreases the screen effectiveness
Equation for Screen efficiency is
recovery x rejection
The material passing one screening surface and retained on a subsequent surface is called
intermediate material
Size measurement of ultrafine particles can be best expressed in terms of
surface area/ unit mass
The hardness of a mineral is a criterion of its resistance to crushing.
Which of the following is an example of a hard material?
sapphire
Mesh indicates the number of holes per
Linear inch
Describe:
Tyler Standard Sieve Series
US Standard Sieve Series
International Test Sieve Series
Tyler Standard Sieve Series: consecutive mesh have sqrt(2) ratio
US Standard Sieve Series: consecutive mesh have fourth root of 2 ratio
International Test Sieve Series: similar to both, but have different wire gauges
The standard equipment recommended for automatically carrying out sieve test procedures with accuracy and dependability.
Ro tap shaker (read Screening)
A major expense in crushing and grinding of feed material
Cost of power
For the preliminary breaking of hard rock, we use a ____
Gyratory crusher
Size reduction mechanism used in jaw crushers is ____
Compression
The main size reduction operation in ultrafine grinders is
Attrition
Explain Taggart’s Rule
T= 0.6 * L * S
T: short ton/hr
L: length feed opening, in
S: greatest with of opening, in
if T/S^2 > 0.155: Use Gyratory crusher
if T/S^2 < 0.155: Use Jaw crusher
Size Reduction Mechanism:
Coarse
Fine
Ultrafine
Coarse: Compression
Fine: Impact
Ultrafine: Attrition
As the product becomes finer, the energy required for grinding
increases
To get a fine talc powder from its granules, the equipment used is
Ball mill
Maximum size reduction in a ball mill is done by ______
Impact
The operating speed of a ball mill should be __________ the critical speed.
Less than
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 ___ (multiple answers)
gravitational or centrifugal, buoyant and 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 _____
Re,p <1
In hindered settling, the particles are
A. Placed farther from the wall
B. Not affected by other particles and the wall
C. Near each other
D. None of these
Near each other
Drag co-efficient in hindered settling is __________ that in free settling.
A. Less than
B. Equal to
C. Not necessarily greater than
D. Always greater than
Always greater than
Filter aid is used to ____
A. Increase the rate of filtration
B. Decrease the pressure drop
C. Increase the porosity of the cake
D. Act as a support base for the septum
Increase the porosity of the cake
During the washing of cake ____
A. All the resistances are constant
B. Filter medium resistance increases
C. Filter medium resistance decreases
D. Cake resistance decreases
All the resistances are constant
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
Minimum at the filter medium
The terminal velocity of a small sphere settling in a viscous fluid varies as the ______
a. first power of its diameter
b. inverse of the fluid viscosity
c. inverse square of the diameter
d. square of the difference in specific weights of solid and fluid
Inverse of the fluid viscosity
Buoyant force _____
a. for non-symmetrical bodies is not vertical
b. depends on the depth of the submergence of the floating body
c. depends on the weight of the floating body
d. none of these
Depends on the weight of the floating body
Terminal velocity is ______
a. constant velocity with no acceleration
b. a fluctuating velocity
c. attained after moving one-half of total distance
d. none of these
A constant velocity with no acceleration
Which of the following may prove unsuitable for filtering volatile liquids?
a. pressure filter
b. centrifugal filter
c. gravity filter
d. vacuum filter
Vacuum filter
In washing type plate and frame filter press the ratio of washing rate to the final filtrate rate is ____
a. 4
b. 1
c. ¼
d. ½
¼
Moore filter is a __________ .
A. Leaf filter
B. Press filter
C. Rotary filter
D. Sand filter
Leaf filter
Diatomaceous earth is a/an ______
A. Explosive
B. Filter aid
C. Filter medium
D. Catalyst
Filter aid
Particle diameter in size 50% passes through equipment (undersize) and 50% discharged through equipment (oversize)
Cutpoint Diameter
Critical Diameter
If the radius of a basket centrifuge is halved and the rpm is doubled, then _____
a. linear speed of the basket is doubled
b. linear speed of the basket is halved
c. centrifugal force is doubled
d. capacity of centrifuge is increased
Centrifugal force is doubled
For separation of sugar solution from settled out mud we use _____
Centrifugal filter
Which is the driving force behind free falling body?
gravitational force
A flotation modifier which assists in selectivity (sharpness of separation) or stop unwanted minerals from floating is a/an _____
depressants
Froth floatation is the most suitable for treating ____
Sulphide ores
In Froth Flotation, chemical agent added to cause air adherence is called ____
collector
Pine oil used in froth floatation technique acts as a/an _____
Frother
It is the separation of fluid-solid mixture involving the passage of most of the fluid through a porous membrane which returns most of the solid particles contained in the mixture
filtration
Which of the following types of filter are made to operate to continuously?
a. rotary drum
b. gravity
c. filter press
d. leaf filter
rotary drum
A major expense in crushing and grinding of feed material
Moh’s Scale if Hardness
Trading Game Coming
FAF
QTCD
*Soft:
1.Talc
2.Gypsum
3.Calcite
*Intermediate:
4.Fluorite
5.Apatite
6.Feldspar
*Hard
7.Quartz
8.Topaz
9.Corundum
10.Diamond
Stages of Size Reduction Equipment
*Coarse
Gyratory Crusher
Jaw Crusher
Hammer Mill
*Intermediate
Cone crusher
Crushing rolls
*Fine
Ball Mills
Rod Mills
Parallel metal bars in an inclined stationary frame
Grizzly Screens
Screen frequency controlled by electromagnetic vibrator mounter above and directly to screening surface
Vibrating screen
Composes of rotating perforated drum separating particles from smallest to biggest
Reciprocating Screens
