This set of Iron Making Multiple Choice Questions & Answers (MCQs) focuses on “Petrographic and Other Characteristics of Coal”.
1. Audibert-Arnu and Ruhr dilatometers are used to measure the ___________
a) Dilatometric properties of the coal
b) Pyrometric properties of the coal
c) Electric properties of the coal
d) Optical properties of the coal
View Answer
Explanation: Audibert-Arnu and Ruhr dilatometers are used to measure the dilatometric properties of the coal. Audibert-Arnu dilatometer is more commonly used to obtain the dilatometric properties of the coal.
2. What is required to make high-grade blast furnace coke?
a) Blending
b) Mixing
c) Coating
d) Electroplating
View Answer
Explanation: Blending is required to make high-grade blast furnace coke. Blending can be done either when coal is having inadequate plasticity or when coal is too fluid. Blending is done before using these types of coal in blast furnace operation.
3. Plastometers are used for measuring the plastic properties of coal.
a) True
b) False
View Answer
Explanation: Plastometers like Gieseler, Sapozhnikhov, etc. are available for measuring the plastic properties of coal, and each of these has its respective optima for measuring the plastic properties of the coal. Plastic properties governs the coking potential of the coal.
4. Caking coals on heating undergo both chemical and physical changes.
a) True
b) False
View Answer
Explanation: Caking coals on heating undergo both chemical and physical changes. Caking tendency of the coal is decided by its volatile matter content. All individual particles of caking coal form a mass or cake on heating.
5. What is a measure of the increase in the volume of the coal on heating?
a) Free swelling index (FSI)
b) Free grinding index (FGI)
c) Restrict swelling index (FSI)
d) Hindered swelling index (FSI)
View Answer
Explanation: The free swelling index (FSI) of the coal is defined as the increase in the volume when it is heated under a particular set of conditions without any external restrictions. The FSI of bituminous coal generally increases with the rank of the coal.
6. What gives an idea of the relative grindability or ease of pulverization of the coal?
a) Hardgrovegrindability index (HGI)
b) Handfordgrindability index (HGI)
c) Micumgrindability index (MGI)
d) Hardgrovegrindability index (HGI)
View Answer
Explanation: The Hardgrovegrindability index (HGI) of the coal gives an idea of its relative grindability or ease of pulverization. The amount of coal sample passes through 200mesh after grinding in a special Hardgrove grinding machine determines its value.
7. The HGI values higher than 55 indicate that the coal is ___________
a) Soft
b) Hard
c) Tough
d) Stiff
View Answer
Explanation: The HGI values higher than 55 indicate that the coal is soft. Hard coals have values less than 45. Coals having minimum HGI of 50–52 are considered suitable for economical coke making. Higher is the HGI value, softer is the coal. Soft coal is also easy to grind.
8. The crucible swelling number (CSN) is used to determine the _______________
a) Coking property of the coal
b) Caking property of the coal
c) Electrical property of the coal
d) Mechanical property of the coal
View Answer
Explanation: The crucible swelling number (CSN) is used to determine the coking property of the coal. The method is particularly sensitive to the extent of oxidation of the coal and is also very fast. It finds application in mining to check the extent of oxidation of the coal.
Sanfoundry Global Education & Learning Series – Iron Making.
To practice all areas of Iron Making, here is complete set of 1000+ Multiple Choice Questions and Answers.
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