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Wrought iron is the purest form of iron. Write a reation used for the preparation of wrought iron from cast iron. How can the impurities of sulphur, silicon and phosphorus be removed from cast iron? |
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Answer» Wrought iron contains lesser proportion of carbon contents (0.2 to 0.5%) as compared to cast iron (2.5 to 4.5%). In order to reduce the percentage of carbon, cast iron is heated with haemtite `(Fe_(2)O_(3))` at a temperature above 1073 K in a reverberatory furnace. `Fe_(2)O_(3)(s)+3C(s) overset("heat") to underset(("Cast iron")) (2 Fe(s)) + 2 CO(g)` Lime stone `(CaCO_(3))` is added as flux in the extraction of cast iron from haematite ore. Upon decomposition, it provides CaO. In the Blast furnace, the impurities of silicon, sulphur and phosphorus are converted into their respective oxides. These combine with CaO to form corresponding salts which pass into the slag. `{:(SiO_(2)+CaO to CaSiO_(3) ("Slag")),(SO_(3)+CaO to CaSO_(4)("Slag")),(P_(4)O_(10)+6CaO to 2Ca_(3) (PO_(4))_(2)("Slag")):}` |
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