This set of Pulp and Paper Multiple Choice Questions and Answers (MCQs) focuses on “Sulfite Pulping”.
1. The sulfite pulping process is a full chemical pulping process, using mixtures of sulfurous acid and alkali salts.
a) True
b) False
View Answer
Explanation: The sulfite pulping process is entirely chemical pulping process,which utilizes sulfurous acid and alkali salts to solubilize lignin through the formation of sulfonate functionalities.
2. Find the hidden term.
2H2+CaCO3andharr; Ca(HSO3)2+ __________
a) H2O and CO2
b) H2CO3
c) H2SO4
d) HSO4 and CO2
View Answer
Explanation: The liquor is made at the mail by burning sulfur to form SO2 and dissolving this in water to produce sulfurous acid.
3. What is the correct definition of cooking liquor?
a) Consisting of a mixture of KMnO4 together with one of the bases
b) Consisting of a mixture of H2O together with one of the bases
c) Consisting of a mixture of CO2 together with one of the bases
d) Consisting of a mixture of SO2 together with one of the bases
View Answer
Explanation: The cooking liquor is a fresh pulping liquor for the sulfite process, it consists of a mixture of KMnO4 together with one of the bases.
4. Brown liquor is also known as red liquor in the Sulfite pulping.
a) True
b) False
View Answer
Explanation: Brown liquor is the waste liquor from the Sulfite pulping process.
5. _________ is cooking liquor and has equal amounts of free SO2 and combined SO2.
a) Circular liquor
b) Square liquor
c) Triangular liquor
d) Green liquor
View Answer
Explanation: Square liquor is cooking liquor that has equal amounts of free SO2 and combined SO2. Since the actual species is all HSO3,there will be very little buffering capacity unless a buffer such as sodium.
6. What is the range of pH required in Acid sulfite process?
a) 1.5-2
b) 2.5-5
c) 3-5
d) 11-12
View Answer
Explanation: The acid sulfite process uses a cooking liquor that is strongly acidic (pH 1.5-2, and, therefore, has a preponderance of free SO2 in solution), with a pulping temp. of 125-145 degree celcius.
7. A full chemical pulping process with higher liquor pH(3-4),
a) 2-1
b) 3-4
c) 6-7
d) 12-13
View Answer
Explanation:A full chemical pulping process with higher liquor pH(3-4), and nearly equal amounts of free and combined SO2 in the liquor is known as the bisulfate process.
8. Magnefite process is used at pH at 4.5 and 160 degree celcius with _________ as the base.
a) Cu(2+)
b) Cl
c) Br
d) Mg (2+)
View Answer
Explanation: The magnefite process is used at pH at 4.5 and 160 degree celcius with Mg as base.
9. _________ is the process of two stage sulfite process with a mild sulfite stage followed by an acid sulfite stage to give a pulp with maximum yield.
a) Stora
b) Sulfite
c) Sivola
d) Grandula
View Answer
Explanation: Stora is the process of two stage sulfite process with a mild sulfite stage followed by an acid sulfite stage.
10. __________ is a three stage sulfite process for producing dissolving pulps.
a) Stora
b) Sulfite
c) Sivola
d) Grandula
View Answer
Explanation: The Sivola process is a three stage sulfite process which produces dissolving pulps. The neutral sulfite stage provides sulfonation of lignin which are easily removed, the second stage of acid sulfite is then uilized to decrement the molecular weight of cellulose for viscosity control and hemicelluloses for their complete removal, and the final stage removes the hemicellulose.
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