Wrought iron is prepared from cast iron by oxidizing impurities in a reverberatory furnace lined with $\mathrm{haematite}$. This $\mathrm{haematite}$ oxidizes carbon to carbon monoxide.

${\mathrm{Fe}}_2{\mathrm{O}}_3 + 3\mathrm{C}\to \underset{\mathrm{wrought} \mathrm{iron}}{2\mathrm{Fe}} + 3\mathrm{CO}$

Limestone is added as flux and $\mathrm{sulphur}$, silicon and phosphorous are oxidized and removed. Hence pure iron called wrought iron is produced.