This set of Iron Making Multiple Choice Questions & Answers (MCQs) focuses on “Thermal and Chemical Features of Blast Furnace”.
1. In blast furnace, Inputs per thm is equal to _______
a) Outputs per thm
b) Heat outputs per thm
c) Outputs per g
d) Output per kg
View Answer
Explanation: For blast furnace, Inputs per thm is equal to outputs per thm. Amount of each element remains the same before and after the blast furnace operation. It follows the law of conservation of mass i.e. mass can neither be created nor be destroyed.
2. In blast furnace, Heat input per thm is equal to heat output per thm.
a) True
b) False
View Answer
Explanation: For blast furnace, Heat input per thm is equal to heat output per thm. Heat input is equal to the heat released from exothermic reactions and the heat absorbed from endothermic reactions. It follows the law of conservation of energy i.e. energy can neither be created nor be destroyed, it can change its form from one to another.
3. A blast furnace hot metal containing 3.6 wt.% C, 1.4wt.% Si, the rest being Fe. The ore has 85% Fe2O3, the rest being 15% gangue of SiO2 and Al2O3. Calculate the weight of ore used in per tonne of hot metal production.
a) 1500 Kg
b) 1605 Kg
c) 1209 Kg
d) 1597 Kg
View Answer
Explanation: Fe-Balance: WFe in ore = WFe in hot metal = 1000 × 0.95 = 950 kg
Wore = 950 × MFe2O3/MFe × 100/85, where M denotes the atomic mass.
Note that M of Fe2O3 is 160 and M of Fe is 56, Wore = 1597 kg
4. Calculate the amount of carbon in coke containing 85% carbon and 15% ash. Coke consumption is 800 kg per tonne of hot metal.
a) 650 Kg
b) 580 Kg
c) 670 Kg
d) 680 Kg
View Answer
Explanation: Coke consumption is 800 kg. 85% is carbon.
Therefore, weight of carbon is, 800 × 0.85 = 6800.
Coke generally contains 80-90 % of carbon.
5. The blast furnace is a ______________
a) Continuous countercurrent reactor
b) Discontinuous countercurrent reactor
c) Continuous non-countercurrent reactor
d) Discontinuous non-countercurrent reactor
View Answer
Explanation: The blast furnace is a continuous countercurrent reactor in a steady state.
Burden materials are charged from the top and is reduced by gases (CO mainly) coming from the bottom.
6. Amount of CO in 53.67 kgmol of CO and CO2 is __________
a) 37.57 kgmol
b) 16.10 kgmol
c) 18.89 kgmol
d) 38.76 kgmol
View Answer
Explanation: Molar fraction of CO = 28/(28 + 12) = 0.7 = molar mass of CO2/molar mass of CO2 & CO, and of CO2 = 12/(28 + 12) = 0.3 = molar mass of CO/molar mass of CO2 & CO.
Amount of CO = 53.67 × 0.7 = 37.67 kgmol.
7. Carbon going out through BF gas = Carbon input through coke ________
a) Carbon in hot metal
b) Carbon in slag
c) Carbon in BF gas
d) Carbon in hearth region
View Answer
Explanation: Carbon going out through BF gas = Carbon input through coke – Carbon in hot metal.
Carbon is present in BF gas in the form of CO and CO2.
Coke charged into the blast furnace contains 80-90% carbon and the rest is ash.
8. Enthalpy of reaction = Sum of enthalpies of formation of products __________
a) Sum of enthalpies of formation of reactants
b) Sum of entropies of formation of reactants
c) Sum of free energy of formation of reactants
d) Sum of entropies of formation of products
View Answer
Explanation: Hess’ law validates the above relation. According to Hess’ law, the difference of the sum of enthalpies of formation of products & the sum of enthalpies of formation of reactants gives the enthalpy of reaction. It follows the law of conservation of energy i.e. energy can neither be created nor be destroyed.
Sanfoundry Global Education & Learning Series – Iron Making.
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