This set of Iron Making Multiple Choice Questions & Answers (MCQs) focuses on “Assessment of Coke Quality”.
1. Coke is cellular, porous, heterogeneous material in both physical and chemical properties.
a) True
b) False
View Answer
Explanation: Coke is cellular, porous, heterogeneous material in both physical and chemical properties.
Coke for blast furnaces is sufficiently strong to resist shattering during handling prior to charging, reactive enough to produce carbon monoxide as it descends.
2. Which test is performed to test strength of coke against both impact and abrasion?
a) Tumbler
b) Frank
c) Micum
d) Shatter
View Answer
Explanation: Tumbler test is performed to test strength of coke against both impact and abrasion. Various types of tumbler tests have been developed using drums of different sizes rotated at different speeds.
3. The Micum indices M40 and M10 are defined as the percentage of coke retained on the 40 mm screen and that passing through the 10 mm screen respectively.
a) True
b) False
View Answer
Explanation: The Micum indices M40 and M10 are defined as the percentage of coke retained on the 40 mm screen and that passing through the 10 mm screen respectively. Coke with high M40 and low M10 indices are desirable in all blast furnaces.
4. The IRSID test determines the strength of __________
a) Smaller-sized coke up to 20 mm
b) Smaller-sized coke up to 50 mm
c) Smaller-sized coke up to 70 mm
d) Smaller-sized coke up to 90 mm
View Answer
Explanation: The IRSID test determines the strength of smaller-sized coke (up to 20 mm). Identical drum is used as in the Micum drum. It is first performed in IRSID’s university in France at later adopted by ISO.
5. The ASTM tumbler test is a modified version of the ___________
a) Micum test
b) Tumbler test
c) Frank test
d) Shatter test
View Answer
Explanation: The ASTM test is a modified version of the Micum test and shows the abrasion characteristics of coke. The stability factor is reported through the percentage of coke retained on a 25.4 mm screen, and the hardness factor through the percentage of coke retained on 6.35 mm screen.
6. Which type of relationship exists between the reactivity and the resistance of coke?
a) Direct
b) Indirect
c) No relationship
d) Linear
View Answer
Explanation: The reactivity of coke has a direct relationship with the resistance. The coke offers resistance to CO2 attack during the solution loss reaction (C + CO2 = 2CO). High reactivity lead to high solution loss.
7. Which method for measuring coke reactivity is the universal method for measuring the coke reactivity?
a) Japanese
b) Korean
c) American
d) Indian
View Answer
Explanation: Japanese method for measuring coke reactivity is the universal method for measuring the coke reactivity. This method is developed by Nippon Steel Corporation (NSC). The NSC test is similar to the standard iron ore reducibility test. Some appropriate alterations are made in the apparatus dimensions and the test conditions to make it fit for measuring the reactivity of coke.
8. The coke with a high CRI value has a low CSR and vise-versa.
a) True
b) False
View Answer
Explanation: Coke with a high CRI value generally has a low CSR and vise-versa. For high-quality coke used in large blast furnaces a minimum CSR of 60 and maximum CRI of 28 are desirable.
9. The petrographic analysis is the most useful feature in ______________
a) Selecting and blending the coals
b) Selecting the coals
c) Blending the coals
d) Blending the coals
View Answer
Explanation: The petrographic analysis is the most useful feature in selecting and blending coals among all the characteristics (Chemical properties, Rheological properties, Dilatometric properties, Agglomerating properties, Petrographic analysis).
10. MOF diagram shows a relationship between Gieseler fluidity and _________
a) Vitrinite reflectance
b) Exinite and inertinite reflectance
c) Exinite reflectance
d) Inertinite reflectance
View Answer
Explanation: The Japanese researchers have developed a relationship between Gieseler fluidity and vitrinite reflectance. This is obtained from petrographic analysis and is used to formulate blends for coke making. It is represented by the MOF diagram.
Sanfoundry Global Education & Learning Series – Iron Making.
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