Wrought iron is the purest form of iron. Write a reaction used for the preparation of wrought iron from cast iron. How can the impurities of sulphur,silicon and phosphorus be removed from cast iron?

(N/A) Wrought iron is prepared from cast iron by oxidizing impurities in a reverberatory furnace lined with haematite $(Fe_2O_3)$.
The chemical reaction involved is:
$Fe_2O_3(s) + 3C(s) \rightarrow 2Fe(s) + 3CO(g)$
To remove impurities like sulphur,silicon,and phosphorus,limestone $(CaCO_3)$ is added as a flux. The impurities are oxidized to their respective oxides ($SO_2$,$SiO_2$,$P_4O_{10}$) and are removed as slag. For example,$SiO_2$ reacts with limestone to form calcium silicate slag $(CaSiO_3)$. The molten metal is then removed and freed from the slag by passing it through rollers.