JEE Main 2025 · Chemistry · d- and f-Block Elements and Metallurgy · easy

In the Bessemer converter used for copper extraction from the matte (Cu2S with FeS), silica is added mainly because

Single correct option

In the Bessemer converter used for copper extraction from the matte (

\mathrm{Cu_2S}

with

\mathrm{FeS}

), silica is added mainly because

A. it reduces $\mathrm{Cu_2O}$ to copper
B. it oxidises $\mathrm{Cu_2S}$ to $\mathrm{Cu_2O}$
C. it combines with $\mathrm{FeO}$ formed on blowing air, giving $\mathrm{FeSiO_3}$ slag
D. it acts as a reducing agent for $\mathrm{SO_2}$

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Answer: (C) it combines with $\mathrm{FeO}$ formed on blowing air, giving $\mathrm{FeSiO_3}$ slag

Blowing air through the molten matte oxidises

\mathrm{FeS}

first to

\mathrm{FeO}

. Silica (

\mathrm{SiO_2}

) is an acidic flux which combines with the basic oxide:

\mathrm{FeO+SiO_2\to FeSiO_3}

(slag, floats on top and is removed). Then

\mathrm{Cu_2S}

is partly oxidised to

\mathrm{Cu_2O}

, and self-reduction

\mathrm{2Cu_2O+Cu_2S\to6Cu+SO_2}

gives blister copper.

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