During the industrial extraction of iron in the blast furnace, limestone (\text{CaCO}_3) i… — JAMB UTME

During the industrial extraction of iron in the blast furnace, limestone ( $\text{CaCO}_3$ ) is decomposed by heat to form calcium oxide ( $\text{CaO}$ ), which then reacts with silica ( $\text{SiO}_2$ ) impurities present in the ore. Which of the following chemical formulas represents the molten slag produced from this reaction?

$\text{CaSiO}_3$ Answer
B
$\text{FeSiO}_3$
C
$\text{CaCO}_3$
D
$\text{CaO}$

Answer

\text{CaSiO}_3

(Calcium trioxosilicate(IV))

In the lower region of the blast furnace, limestone (

\text{CaCO}_3

) decomposes into calcium oxide (

\text{CaO}

). The basic

\text{CaO}

reacts with acidic silica (

\text{SiO}_2

) impurities present in hematite to form molten calcium trioxosilicate(IV) (

\text{CaSiO}_3

), commonly known as slag.

Step-by-Step Solution

Identify thermal decomposition of limestone

\text{CaCO}_3(s) \rightarrow \text{CaO}(s) + \text{CO}_2(g)

High temperatures in the blast furnace break down limestone into basic calcium oxide.

Combine basic oxide flux with acidic silica impurity

\text{CaO}(s) + \text{SiO}_2(s) \rightarrow \text{CaSiO}_3(l)

Calcium oxide acts as a basic flux that neutralizes acidic sand/silica impurities to form molten slag.

Key Concept

Slag Formation in Iron Extraction

Estimated Time:45s

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