Pulp and Paper Multiple Choice Questions on “Papermaking Control Chemistry”.
1. _________ is usually anionic if it has any charge and may contribute to anionic trash.
a) Dispersant
b) Flocculation
c) De-flocculation
d) Pith
Answer: d
Clarification: Calcium ions form precipitates with wood pitch. It could be natural or manufactured or derived from petroleum, coal tar, and plants.
2. Wood pitch is concentrated in _________ cells and may be squeezed out in refining, paper pressing, and other operations.
a) Collenchyma
b) Parenchyma
c) Girth
d) Phloem
Answer: b
Clarification: The cellular tissue, typically soft and succulent, found chiefly in the softer parts of leaves, pulp of fruits, bark and pith of stems, etc. Pitch could contribute to foam formation when the pitch molecules attach to air bubbles.
3. Cationic retention aids such as _________ may help bind wood and other pitch materials to the stock to prevent their concentration in the system.
a) Silicon
b) Alum
c) Copper
d) Aluminium
Answer: b
Clarification: The specific compound is the hydrated KAl(SO4)2. Pitch may be absorbed on talc if the pitch is dispersed.
4. _________ are utilised to keep the pitch from forming aggregates, but may contribute to poor retention and foaming.
a) Dispersant
b) Flocculation
c) De-flocculation
d) Pith
Answer: a
Clarification: The dispersing agent or a plasticizer added to a suspension, usually a colloid, to improve the separation of particles and to prevent settling. They consist normally of 1 or more surfactants, but might also be gases.
5. In addition to surfactants, finely divided solids can contribute to foam problems.
a) True
b) False
Answer: b
Clarification: These solids include fillers, alumina, fines, and other colloids that can surround air bubbles to decrease the surface tension.
6. _________ unlike other dyes, are soluble in moderately polar to non-polar materials like the lower alcohols and oil.
a) Acidic dye
b) Basic dye
c) Cationic dye
d) Anionic dye
Answer: b
Clarification: They have a tendency to work unevenly and may give a surface that appears somewhat like granite. This dye is generally synthetic, that act as bases, and which are actually aniline dyes.
7. Pulps with low cellulose viscosity refine faster, so the refiner operator should be aware of changes in the pulp viscosity.
a) True
b) False
Answer: a
Clarification: The level of refining can be followed with Simons in 1950 stain of fibers observed through a microscope. Even without staining, refining can be followed qualitatively with microscopic observation.
8. The reason the _________ work by different mechanisms and affect components of drainage differently because of improved _________ at the flat boxes which doesn’t mean the consistency at the couch will be improved.
a) Drainage aids
b) Online sensors
c) Offline sensors
d) Simons sensors
Answer: a
Clarification: H2O is the carrier of all major paper components and typical furnish consistencies of 0.3−1.5% are required to achieve the paper properties desired, it becomes obvious that the removal of large quantities of H2O is
the key to better productivity and costs.
9. _________ usually requires manual sampling of process streams which is critical to obtain a representative sample.
a) Drainage aids
b) Online sensors
c) Offline sensors
d) Simons sensors
Answer: c
Clarification: This isn’t easy in the case of paper machine white H2O; in this case sampling of more than one region may be required, and each sample must be representative of the area from which it is collected.
10. _________ are superior to off-line measurements that take operator time and data is available immediately to control the process.
a) Drainage aids
b) Online sensors
c) Offline sensors
d) Simons sensors
Answer: b
Clarification: Measurements of pH, conductivity, temperature, flow rates, zeta potential, certain ions, and flow rates are well established and do not require operator time to collect.
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