# Iron Making Questions and Answers – Reichardt’s Diagram and Reserve Zones

This set of Iron Making Multiple Choice Questions & Answers (MCQs) focuses on “Reichardt’s Diagram and Reserve Zones”.

1. What is the main physical property of matter with which Reichardt’s Diagram deals?
a) Refractive index
b) Heat capacity
c) Thermal conductivity
d) Mass

Explanation: Reichardt’s Diagram deals with the relative variation of heat capacity of solid charge and hot blast. The results are used to understand the thermal interactions in the blast furnace.

2. How does the heat capacity of solid charge vary from top to bottom of a blast furnace?
a) The heat capacity increases from top to bottom
b) The heat capacity decreases from top to bottom
c) The heat capacity remains constant through out
d) Nothing can be told about the heat capacity

Explanation: The heat capacity of solid charge increases as we go from top to bottom of a blast furnace. The solid charge undergoes endothermic reactions and phase transformations which require heat as we move from top to bottom.

3. Which kind of reaction is responsible for the increase in heat capacity of solid charge in the lower part of the BF?
a) Exothermic reaction
b) Explosive reaction
c) Endothermic reaction

Explanation: Endothermic reactions are responsible for the increase in the heat capacity of the solid charge in the lower part of the furnace. Endothermic reactions such as boudward reaction occur in the lower part and consume a lot of heat, increasing the perceived heat capacity.

4. What is the temperature range in the ‘Thermal Reserve Zone’ of a BF?
a) 800°C-900°C
b) 950°C-1050°C
c) 1200°C-1300°C
d) 600°C-700°C

Explanation: The operating temperature in the TRZ of a blast furnace is around 950°C-1050°C. Any increase or decrease in this temperature indicates faulty operation of the furnace.

5. What kind of equilibrium can be expected in the ‘Chemical Reserve Zone’ of an ideal blast furnace?
a) Fe-wustite-gas
b) Fe2O3-wustite-gas
c) Fe-C-gas
d) H-Fe-gas

Explanation: The chemical reserve zone is a zone of chemical equilibrium where the reduced charge (Fe) unreduced charge (wustite) and reducing agent (gas) are in equilibrium.

6. What is the height of the ‘Thermal Reserve Zone’ in a typical blast furnace?
a) <1 m
b) 1m-4m
c) 6m-8m
d) >8m

Explanation: The TRZ is a zone where no heat exchange takes place; it is a narrow zone where the heat capacity of solid charge and gas becomes equal.

7. What assumptions are made regarding heat capacity of blast furnace gas in the construction of Reichardt’s Diagram?
a) The heat capacity increases as the gas goes upwards
b) The heat capacity remains same
c) The heat capacity decrease as the gas goes upwards
d) The heat capacity fluctuates with height

Explanation: Since the blast furnace gas does not undergo any phase transformation or reaction (the endothermic reactions are well compensated by exothermic reactions) as such, the heat capacity can be assumed to be constant with height.

Sanfoundry Global Education & Learning Series – Iron Making.

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