Question

How is wrought iron prepared from cast iron?

Answer 1

Cast iron is an impure form of iron obtained in the initial stages of refining. However wrought iron is the purest form of iron at present. Wrought iron is obtained from cast iron why removing all the impurities present. Impurities are oxidized to obtain the pure form of iron.

Complete step by step answer:
Cast iron is a group of iron-carbon alloys with a carbon content more than 2%,it is useful as it has a low melting point temperature.
Wrought iron is an iron alloy with a very low carbon content (< 0.08%) in contrast to cast iron that has a carbon content of over 2 %.
It is a semi-fused form of iron with fibrous slag of up to 2%, which gives a resemblance of grain wood that is visible when it is etched or bent. Wrought iron is tough, malleable, ductile, corrosion resistant, and easily welded when compared to cast iron.
Cast iron contains impurities of silicon and manganese. It also has traces of sulfur and phosphorus. Wrought iron is obtained by oxidizing impurities in a reverberatory furnace lined with ferric oxide. The ferric oxide oxidizes carbon to carbon monoxide.

$\begin{aligned} & \text{F}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}\text{ + 3C }\to \text{ 2Fe + 3CO} \\\ & \text{ wrought iro}{{\text{n}}^{{}}} \\\ \end{aligned}$

This is how wrought iron is obtained from impure iron alloy, cast iron.

Note: In the process of obtaining pure iron, limestone is added to the furnace as a flux. Limestone reacts with the silicon oxide present as an impurity and converts into fusible slag of calcium silicate.