Question

How are metals refined by Bessemerisation?

Hint:

Bessemerisation = blowing air through molten metal to oxidize and remove impurities.

Answer 1

Step 1: Definition.
Bessemerisation is a metallurgical process used for the purification of metals, particularly for converting impure molten pig iron into steel or copper matte into pure metal.
Step 2: Principle.
In this process, air or oxygen is blown through molten metal, which oxidizes impurities such as carbon, silicon, sulfur, and iron into gaseous oxides or slag that can be removed.
Step 3: Reactions involved.
\[ 2C + O_2 \rightarrow 2CO, \quad Si + O_2 \rightarrow SiO_2, \quad Fe + O \rightarrow FeO \] FeO then combines with silica to form slag (FeSiO$_3$), which floats and is removed.
Step 4: Application.
Used in the refining of copper and steel.
Step 5: Example.
In the Bessemer converter, impure blister copper is oxidized and converted into pure copper metal.