REACTION MODEL FOR THE AOD PROCESS.

Abstract

A reaction model has been developed for the AOD stainless steelmaking process that predicts the rates of oxidation of carbon and chromium. The reaction model is based on the assumptions that the injected oxygen primarily oxidizes chromium in the tuyere zone and that the Cr//2O//3 formed oxidizes the carbon as it rises in the bath with the argon bubbles. It was further assumed that the oxidation of carbon by Cr//2O//3 is the rate-controlling reaction and is controlled by the liquid-phase mass transfer of carbon to the bubble surface. The model was tested against operating data obtained from 82 t heats of Type 409 stainless steel, and there is good agreement between the predicted and observed rates of oxidation. The model was extended to other operating conditions such as different O//2/Ar ratios and the refining of 18-8 stainless steel. 10 refs.