Question

The smelting of iron in a blast furnace involves the following processes:
A.Combustion
B.Reduction
C.Slag formation
D.Sublimation

Answer 1

Hint: Smelting: - Smelting is a process by which a metal is obtained from its ore by heating in the presence of oxidizing agents such as air, or in the presence of reducing agents such as coke, charcoal and coal.

Complete step by step answer:
Combustion:- Combustion is the process in which substances react with oxygen and transfer energy to surrounding in the form of heat and light. During smelting, the air is blown from the bottom of the furnace and is heated using hot waste gases from the top of the furnace. The coke burns in a blast of hot air to form carbon dioxide.
Reduction:- The act by which something is reduced. During smelting, high temperatures are present at the bottom of the furnace which convert carbon dioxide with carbon into Carbon monoxide (main reducing agents of furnace).
\[\;Carbon{\text{ }}dioxide{\text{ }}\left( {C{O_2}} \right){\text{ }} + {\text{ }}carbon{\text{ }} \to {\text{ }}carbon{\text{ }}monoxide{\text{ }}\left( {CO} \right)\;\]
They convert iron oxide \[\left( {{\text{ F}}{e_2}{O_3}} \right)\;\]into iron.
\[F{e_2}C{o_3}\; - - - -> {\text{ }}2{\text{ }}Fe{\text{ }} + {\text{ }}3CO\]
Slag formation:- Slag is the waste matter separated from the metal during smelting. During smelting, limestone is added which produces slag which melts and runs to the bottom. Furnace heat decompose the limestone to give calcium oxide \[\left( {CaO} \right).\]
Sublimation: Sublimation is transition of substance directly from solid to gas phase.
So except sublimation, above three processes involve the smelting of iron in a blast furnace.
Thus option A, B, C are correct.



Note:
Metal smelting is generating wastes that contain copper, lead, arsenic, zinc etc. which has a hazardous effect on the environment producing water waste and slag or releasing gases like sulphur dioxide causing adverse effects on human beings. Labour working in the smelting industry have reported respiratory illness.