This set of Mechanical Operations Multiple Choice Questions & Answers (MCQs) focuses on “Colloid Mill”.
1. The height of suspension is determined by _____
a) Particle weight
b) Particle size
c) Magnetic field
Explanation: Suspended tramp iron magnets installed flat over a conveyer or at an angle of conveyer pulley, height of suspension depends up on the particle size.
a) Burden depth
b) Correction factor
c) Kynch formula
d) Crab’s rule
Explanation: The above formula represents the burden depth De, where C is the capacity and W is the width of the belt and V is belt speed.
3. For magnetic drums, area covered is around ____
Explanation: Feed is usually on the top, vertical center line and the magnet are covers 1650 of the area is covered.
4. Electromagnetic field controls are necessary for _____
a) Grate magnets
b) Metal detectors
c) Magnetic drums
d) Cobbing trims
Explanation: The magnetic wet drums is applied where the simple electric fields control is necessary, having low maintenance cost and operating cost.
5. Magnetic filters can handle up to _____
a) 2000 gal/hr
b) 1500 gal/hr
c) 1000 gal/hr
d) 800 gal/hr
Explanation: Capacities of magnetic filters are comparatively low , and the largest filter will handle about 2000 gal/hr for a low viscosity liquid.
6. Dry magnetic separators can handle feed up to _____
a) 5 T/hr
b) 2 T/hr
c) 10 T/hr
d) 12 T/hr
Explanation: Dry magnetic separator having an 18 inch wide cross belt separator with two magnet poles will handle up to 2 T per hour.
7. A 100 mesh screen and 2700 area resembles, which of the drum separators?
a) High speed high intensity
b) High speed low intensity
c) Low speed high intensity
d) Low speed low intensity
Explanation: This separators is defined to treat finely 100 mesh and finer particles and to produce very high grade magnetic concentrate product.
8. Which of the following is based on the surface charge?
a) Magnetic separator
b) Electrostatic separator
c) Ball mill
d) Camber separator
Explanation: The principle of electromagnetic separator is based on the fact that, if one or more of the materials in a granular mixture can receive a surface charge.
9. When the surfaces of two dissimilar materials are brought into contact each receive a surface charge, this phenomena is called _____
a) Contact electrification
b) Similar electrification
c) Bypass contact
d) Central attraction
Explanation: The surfaces of two dissimilar materials are brought into contact each receive a surface charge, this phenomena is Contact electrification or frictional electrification.
10. _____ is having the property of transmitting electric force without conduction.
c) Para electric
Explanation: A dielectric particle remains essential polarized because of inability to redistribute electrons and thus no charge is generated.
Sanfoundry Global Education & Learning Series – Mechanical Operations.
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