This set of Iron Making Multiple Choice Questions & Answers (MCQs) focuses on “Reactions of Manganese and Titanium”.
1. MnO is more stable than FeO.
a) True
b) False
View Answer
Explanation: This reaction MnO) + C(s) = [Mn] + CO(g) is possible only above 1400°C. Therefore, MnO reduction by carbon occurs primarily in the hearth region. Reduction of FeO occurs at temperature lower than 1400°C.
2. Range of recovery of manganese for basic slags varies between _________
a) 60% and 70%
b) 50% and 70%
c) 60% and 80%
d) 40% and 70%
View Answer
Explanation: Range of recovery of manganese for basic slags varies between 60% and 70% and between 50% and 60% for acids lags. It is done by increasing activity of MnO in the slag by using higher slag basicity.
3. Titanium is present in blast furnace raw materials as ____________
a) Ilmenite
b) Bauxite
c) Pyrite
d) Limestone
View Answer
Explanation: Titanium is usually present in blast furnace raw materials as Ilmenite (FeO.TiO2) and occasionally as Rutile (TiO2). Bauxite is an ore of Al. Pyrite is an ore of Cu. Limestone is an ore of calcium.
4. TiO2 is more stable than SiO2.
a) True
b) False
View Answer
Explanation: TiO2 is more stable than SiO2, and is therefore reduced to a much lesser extent at any given hearth temperature. Titanium also forms stable carbide, nitride and carbo-nitride.
5. Titanium also forms stable carbide, nitride. These compounds have high melting points and low solubilities in liquid iron.
a) True
b) False
View Answer
Explanation: These compounds have high melting points and low solubilities in liquid iron and they separate to form encrustations on the bosh walls, hearth walls and the hearth bottom, resulting in accretion build-up on the blast furnace bottom region lining. This can often lower the furnace campaign life since the highest temperatures prevail in this region.
6. Ti content of hot metal increases with greater reduction of SiO2 and MnO.
a) True
b) False
View Answer
Explanation: Both laboratory and plant data have shown that the Ti content of hot metal increases with greater reduction of SiO2 and MnO, as expected theoretically. While the wt.% Ti in metal is less than 0.15, the wt.% TiO2 in slag may be in the range of 0.3–1.
7. It is necessary to maximise manganese recovery in hot metal.
a) True
b) False
View Answer
Explanation: Whereas the lowest contents of silicon and sulphur in hot metal are desired, it is necessary to maximise manganese recovery in hot metal. Manganese is an input into blast furnaces through iron ore, and sometimes through the deliberate addition of manganese ore. It is present as MnO2, which gets reduced to Mn3O4, and subsequently to MnO in the blast furnace stack by indirect reduction.
8. MnO is reduced by C through reaction (MnO) + C(s) = [Mn] + CO(g).
a) True
b) False
View Answer
Explanation: This reaction is possible only above 1400°C; therefore, MnO reduction by carbon occurs primarily in the hearth region, either when the liquid slag containing MnO flows down through the coke bed or during reaction in the hearth between metal and slag.
9. The manganese content of hot metal ranges between 0.2% and 1.5%.
a) True
b) False
View Answer
Explanation: The manganese content of hot metal ranges between 0.2% and 1.5%, and the MnO content of the slag is also approximately the same. Recovery of manganese in the hearth can be increased by: Increasing activity of MnO in the slag by using higher slag basicity, Increasing the slag and metal temperatures, Increasing the silicon content of hot metal.
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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