A new mathematical model is developed to solve transport of FeO with an apparent redox reaction coupled with a model of thermal convection in a glass tank furnace. A numerical method is proposed to calculate the distribution of FeO with a non-equilibrium reaction in a flow field. Computer simulation enables prediction of the FeO concentration, thermal conductivity, and optical characteristics. It is apparent that chemical homogeneity is attained by residence time and temperature, and that it is more uniform than the mechanical homogeneity by glass flow.