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On the basis of Ellingham's diagram explain the principle of extraction of iron from its oxide ore. |
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Answer» Solution :1. Thermodynamcs helps us to understand how coke REDUCES the oxides of IRON. The Ellingham diagram for FE. ` to FeOFe to Fe_(2)O_(3) to CO` and `CO to CO_(2)` are given above. 2. From the above Ellingham diagram, it is known that `Delta G^@` vs T plot for the reaction `Fe to FeO` goes up and `C to CO` line joins the `Fe to FeO` line. 3. Above 1073K. `AG^@` of `C to CO` becomes less than `AG^@` of `Fe toFeO` and hence carbonitselfisoxidizedtocarbonmonoxide. Therefore, carbonbecomesverygoodreducing agent which reduces FeO to Fe at the temperature range 900-1500K. `FeO(s) + C(s) to Fe(s//I) + CO(g)` 4.At temperature below 800K, standard free energy change for `CO to CO_(2)` line is less than `Fe to Fe_(2)O` line. Therefore, carbon monoxide is the best REDUCING agent and is oxidised to carbon dioxide by reducing `Fe_(2)O_(3)` and `Fe_93)O_(4)` to Fe. `3 Fe_(2)O_(3) + CO to 2Fe_(3)O_(4) + 4CO_(9)`. `Fe_(3)O_(4) + 4CO to 3Fe + 4CO_(2)`. `Fe_(2)O_(3) + CO to 2FeO + CO_(2)` 5.At temperature below 1073K, CO reduces FeO to Fe `FeO to Fe +CO_(2)`. 
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