Question

Among the reactions (a) − (d), the reaction(s) that does/do not occur in the blast furnace during the extraction of iron is/are:
(a) ${\text{CaO + Si}}{{\text{O}}_{\text{2}}} \to {\text{CaSi}}{{\text{O}}_{\text{3}}}$
(b) ${\text{2F}}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}{\text{ + CO}} \to {\text{2F}}{{\text{e}}_{\text{3}}}{{\text{O}}_{\text{4}}}{\text{ + C}}{{\text{O}}_{\text{2}}}$
(c) ${\text{FeO + Si}}{{\text{O}}_{\text{2}}} \to {\text{FeSi}}{{\text{O}}_{\text{3}}}$ ​
(d) ${\text{FeO}} \to {\text{Fe + }}\dfrac{{{\text{1}}}}{{\text{2}}}{\text{O2}}$
A.(a)
B.(a) and (d)
C.(c) and (d)
D.(d)

Answer 1

The ores of iron usually used for iron extraction are haematite $\left( {{\text{F}}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}} \right)$ and magnetite $\left( {{\text{F}}{{\text{e}}_{\text{3}}}{{\text{O}}_{\text{4}}}} \right)$. These both ores are oxides and can be reduced to iron by heating them with carbon in the form of coke.

Complete step by step answer:
The air blown into the bottom of the furnace is heated using the hot waste gases from the top. The main source of heat in the blast furnace is a highly exothermic reaction of coke.
Oxides ores of iron after concentration through calcination/roasting are mixed with limestone and coke and fed into a blast.
the furnace from its top. Here, the oxide reduced to its metal
The reactions that occur in the blast furnace during the extraction of iron are:
$CaO + Si{O_2} \to CaSi{O_3}$ calcium carbonate molecule breaks down in calcium oxide and carbon dioxide in the slag zone.
$2F{e_2}{O_3} + CO \to 2F{e_3}{O_4} + C{O_2}$. Here carbon monoxide reduces ferric oxide to spongy iron at about 900 K
Molten slag floats on the molten iron and is tapped off separately.
Molten iron is heavier than molten slag, the two liquids are periodically tapped off. The molten iron tapped off from the furnace is solidified into blocks.
Thus, (c) and (d) do not occur in a blast furnace while extraction of iron.

Therefore, we can conclude that the correct answer to this question is option C.

Note:
The different types of iron and steel produced from the blast furnace. These include:
-Cast iron: Primarily contains iron $({\text{Fe}})$, carbon $({\text{C)}}$ and silicon $({\text{Si)}}$but may also contain traces of sulphur, manganese and phosphorus. Its features are hard, brittle, non malleable and more fusible than steel. The structure is crystalline and fractures under excessive tension
-Wrought iron: It is the highly pure iron with all the carbon impurities removed. Its structure is soft with less structural strength. Used to make decorative gates and railings.
-Mild steel: Contains iron with about $0.25\%$ of carbon impurities. The presence of impurities makes this form of steel stronger and harder than pure iron. More the impurities, the harder the steel becomes.
-High carbon steel: Contains the maximum amount of carbon impurities$(1.5\% )$. This presence of extra carbon impurities makes it hard but also gives it brittle characteristics.