Question

The substance used to reduce iron ore to iron in the lower part of the blast furnace is:
A. Coke
B. Charcoal
C. Carbon Monoxide
D. Carbon black

Answer 1

A process of applying heat to the iron ore in order to extract the iron is called smelting. The smelting is performed under the supply of heat and a chemical reducing agent with multiple step reactions in a blast furnace to extract iron.

Step by step answer: In a blast furnace, iron pellets( iron ore), Fuel ( Coke), reducing agent(Limestone) are continuously supplied from the top of the furnace with the complete oxygen flow in the form of hot air blast through the lower part of the furnace with the help of multiple fitted pipes. It is down to make sure the temperature of the furnace remains as desired and the chemical reaction takes place in a continuous manner.

The main chemical reaction which is divided into various steps to extract the iron from the iron ore in a blast furnace is:

$F{e_2}{O_3} + 3CO \to 2Fe + 3CO$ .

The smelting as a process is a multiple step reaction taking place in a blast furnace under the influence action of carbon (supplied in the form of Coke) at a high temperature in the presence of fluxing agent (limestone) to produce pig iron. Iron pellets along with the carbon (Coke) and limestone are preheated in presence of blast air blown to produce carbon monoxide. This carbon monoxide gas at a very temperature produces liquid iron and slag which keeps from falling downward in the furnace.
Hence option A is correct.

Note: Carbon monoxide is not the substance which is primarily used as a source in the smelting process. It is a bi product of the multiple chain of reactions taking place in the blast furnace.