A physico-chemical model has been formulated to provide a description of the reduction of carbon/alumina powder mixture in a flowing nitrogen stream. Simultaneous differential equations were derived on the basis of this model. These equations were solved by numerical methods. The chemical reaction rate expression, which was determined in the chemical reaction control region, was used after the model had been employed for interpreting the experimental data. The expressions for effective gas diffusivities, which have been left as a fitting parameter for calculation of theoretical predictions, were determined as D-eAl2OCO = 4.29 x 10(-5) exp(-25 971 J mol(-1)/RT) m(2) s(-1) D-eAl2OCO2 = 2.49 x 10(-5) exp(-31 512 J mol(-1)/RT) m(2) s(-1) D-eAl2ON2 = 3.13 x 10(-5) exp (-29 718 J mol(-1)/RT) m(2) s(-1) The correlation between the geometrical factor g and half thickness of the sample was determined as g = 1/(1 + 64.7 L), and the correlation between the Sherwood number and Reynolds number was found to be N-Sh = 0.46 N-Re(0.42). The reaction occurring between nitrogen, aluminium oxide and carbon was predicted fairly well by this model.