Pulp and Paper Multiple Choice Questions on “Control Additives”.
1. Residue is a measure of how much material remains on the paper machine wire and is incorporated into the final sheet.
a) True
b) False
Answer: b
Clarification: Retention is a measure of how much material remains on the paper machine wire and is incorporated into the final sheet.
2. What is the name of the hidden part?
___________= {(filler in sheet) / (filler added to furnish)} x 100%
a) Drainage aids
b) First-pass retention
c) Residue
d) Overall retention
Answer: d
Clarification: Overall retention and first-pass retention. These are defined below in the terms of filler, although the retention of fiber fines, sizing agents, and other materials is also crucial.
3. What is the name of the hidden part?
_________= {(filler in sheet) / (filler in heatbox)} x 100%
a) Residue
b) Overall retention
c) First-pass retention
d) Drainage aids
Answer: c
Clarification: A high first-pass retention is important for many aspects of wet end chemistry and sheet quality.
4. _________ are materials that increase the drainage rate of water from the pulp slurry on the wire.
a) Overall retention
b) First-pass retention
c) Residue
d) Drainage aids
Answer: d
Clarification: Drainage aids are materials that inc. the drainage rate of water from the pulp slurry on the wire. Almost any retention aid is opted to improve the drainage rate as fines and fillers are removed.
5. _________are additives used to promote dispersion of fibers which improves formation and could allow higher headbox consistencies.
a) Overall retention
b) First-off retention
c) Formation aids
d) Drainage aids
Answer: c
Clarification: Formation aids are additives used to promote dispersion of fibers which improves formation and could allow higher headbox consistencies. There’s very less information on formation aids in the literature.
6. _________ are utilized to control foaming. Foam exists when some other insoluble gas is mixed into water containing surfactants, which is, surface active agents.
a) Overall retention
b) Defoamers
c) Drainage aids
d) Formation aids
Answer: b
Clarification: Defoamers are utilized to control foaming. Foam exists when air or some other insoluble gas is mixed into water which contain surfactants, which are, surface active agents. Soaps and detergents are good examples of surfactants.
7. Inorganic deposits could frequently be controlled with sequestering agents for the metal ions to keep them in solution by binding them to polar molecules.
a) True
b) False
Answer: a
Clarification: Chemicals are frequently utilized to control organic or inorganic deposits. Inorganic deposits could frequently be controlled with sequestering agents for the metal ions to keep them in sol. by binding them to polar molecules. Sequestering agents include chelants and threshold inhibitors, Chelants such as E.D.T.A., N.T.A., and D.T.P.A. react stoichiometrically.
8. Microorganisms, particularly bacteria and fungi, would grow around the paper machine and produce _________ which consists of proteins and polysaccharides.
a) Slime
b) Spot
c) Crisp
d) Buffer
Answer: a
Clarification: These are very identical to those utilized in bleaching mechanical pulps where metal ions can decompose H2O2 or cause discoloring of the pulp by reacting with phenolic compounds.
9. What is the name of the compound?
a) Quaternary ammonium salts
b) Glutaraldehyde
c) Isothiazolin
d) Dibromonltrilepropionannide
Answer: b
Clarification: Glutaraldehyde’s an organic compound with the formula CH2(CH2CHO2. A pungent colorless oily liquid, glutaraldehyde’s utilized to sterilise medical and dental equipment. It is also utilized for industrial water treatment and as a preservative.
10. What is the name of the compound?
a) Dibromonltrilepropionannide
b) Isothiazolin
c) Glutaraldehyde
d) Quaternary ammonium salts
Answer: a
Clarification: D.B.N.P.A. or 2,2-dibromo-3-nitrilopropionamide’s a quick-kill biocide that easily hydrolyzes under both acidic and alkaline conditions. It’s opted for its instability in water as it quickly kills and then quickly degrades to form a number of products, depending on the conditions which include ammonia, bromide ions, dibromoacetonitrile, and dibromoacetic acid.
>