Pulp and Paper Multiple Choice Questions on “Recycled Fiber Recovery”.
1. Recycling fiber is the process of separating useful fiber from the contaminants of waste paper. A series of processes can be used to accomplish this task.
a) True
b) False
Answer: a
Clarification: A series of processes can be used to accomplish this task.Recycling fiber is the process of separating useful fiber from the contaminants of waste paper.
2. Recycled fiber recovery does not begins at the pulper, which is nothing more than a large blender to disperse pulp into an aqueous slurry.
a) True
b) False
Answer: b
Clarification: Pulping could be done at high or low consistencies utilizing diff. rotors. Shows a high consistency pulper and shows a low consistency pulper with trash removal.
3. A _________ is a long tube with an overhead grapple that’s utilised to manually remove waste that accumulates at the bottom of the tower.
a) Woodward
b) Junk tower
c) Contaminants
d) Surfactants
Answer: b
Clarification: A junk tower’s a long tube with an overhead grapple that’s utilized to manually remove waste that accumulates at the bottom of the tower.
4. A _________ is an enclosed bucket conveyer utilized to automatically remove heavy and floating waste on a continuous basis.
a) Sludge
b) Centrifugal cleaner
c) Continuous junk removal
d) Ink washing
Answer: c
Clarification: It’s an enclosed bucket conveyer utilized to automatically remove heavy and floating waste on a continuous basis.
5. The primary screen rejects could be as high as 50 percent, the primary screen rejects are often sent to a secondary screen to recover usable _________
a) Lignin
b) Pulp
c) Fiber
d) Ink
Answer: c
Clarification: The primary screen rejects are often sent to a secondary screen to recover usable fiber. The stock is then sent to a screening system.
6. An alternative to reverse cleaners is the_________ The unit was developed by Lamort and Centre Technique du Papeterie (C.T.P.) in France.
a) Ink washing
b) Decolorizing methods
c) Flotation clarification of effluent
d) Gyroclean of Fiberprep
Answer: d
Clarification: Gyroclean of Fiberprep was developed by Lamort and Centre Technique du Papeterie (C.T.P.) in France. The manufacturer claims the unit can operate at up to 2 percent consistency. Fiber loss is said to be minimal, and no secondary units are required. Units are available to process 70 to 520 mVhr 300 to 2300 gal/min. The acceleration experienced by the stock’s 700 times normal gravity.
7. _________ involves removal by washing it from the fiber using NaOH, sodium silicate, and hydrogen peroxide with a suitable dispersant in the pulper.
a) Ink flotation
b) Froth flotation
c) Ink washing
d) Froth washing
Answer: c
Clarification: Often the dispersant’s stearic acid and micelle formation occurs in the classic mechanism by which soap is able to make grease and oils water “soluble”. Ink washing involves removal by washing it from the fiber using NaOH, sodium silicate, and H2O2 with a suitable dispersant in the pulper.
8. _________ process is carried out using NaOH, sodium silicate, and H2O2 with a collector system consisting of a surfactant. What is the name of the process?
a) Ink washing
b) Gyroclean
c) Deinking chemistry
d) Reverse cleaners
Answer: a
Clarification: With ink flotation, large ink particle sizes are desired at least 5 /im, but 10-50 im is ideal so the ink can agglomerate and be skimmed from the slurry.
9. After de-inking and cleaning, the dilute pulp slurry must be concentrated for processing further and storage. What is the term used here?
a) Bleaching of secondary fiber
b) Slurry concentration
c) Deinking process
d) Flocculation
Answer: b
Clarification: After de-inking and cleaning, the dilute pulp slurry must be concentrated for further processing and storage. A large disk filter used to conc. a pulp slurry from 0.6 to 10 percent consistency at a mill that recieves 500 tons/day of secondary fiber.
10. _________ or so called wood-containing pulp are bleached with peroxide about 1 percent on pulp, with 4 percent sodium silicate, 50°C.
a) Chemical pulps
b) Softwood pulps
c) Hardwood pulps
d) Mechanical pulps
Answer: d
Clarification: Mechanical pulps are bleached with peroxide (about 1 percent on pulp, with 4 percent sodium silicate, 50°C) or dithionite (hydrosulfite, about 1percent on wood, at pH 5 to 6 mitigate air oxidation of dithionite). Wood free pulps are usually bleached with a single stage hypochlorite treatment (1% on wood as Cl), although an initial chlorination before hypochlorite has also been used.
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