Erosion reactions of carbon by gases

A typical example of dris erosion of metals is the formation of WOaCg) (Rosner and Allendorf, 1970). The Gibbs energies of formation 

The most important indusuial reaction of this kind occurs in die ironmaking blast furnace in which iron oxide ore is reduced by carbon in the form of coke. The mixture is heated by the combustion of part of the coke input in air to produce temperatures as high as 2000 K. The reduction reaction is caiTied out via the gas phase by the reaction 

The kinetics of this reaction, which can also be regarded as an erosion reaction, shows die effects of adsorption of the reaction product in retarding the reaction rate. The path of this reaction involves the adsorption of an oxygen atom donated by a carbon dioxide molecule on die surface of the coke to leave a carbon monoxide molecule in the gas phase. 

The adsorption of carbon monoxide retards the reduction reaction with the rate constant k, followed by the desorption reaction with a rate constant k in the overall rate equation 

The description of the steady state reaction mechanism in terms of die fraction of the active sites occupied by each adsorbed species, 61 for oxygen atoms 

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