At temperatures above 1073K coke can be used to reduce FeO to Fe. How can you justify this reduction with the Ellingham diagram?
The ∆G for the formation of FeO is less negative than ∆G for the formation of carbon monoxide from carbon. The summation of both the ∆G will be negative about 1073K.
Above 1073K the line for the formation of FeO lies above the line for the oxidation of C to CO.
So, in this range, coke will be reducing the FeO and will itself be oxidised to CO.
FeO + C → Fe + CO