1989 Volume 75 Issue 7 Pages 1146-1153
In order to use CO gas purified from off gas of a converter as a bottom blowing gas in combined blowing converter, the metallurgical characteristics brought by bottom injected CO gas were examined in a 5 t test converter. There was no appreciable difference in metallurgical reactions between CO gas and N2 or Ar gas.
In the case of CO gas blowing, decrease in the partial pressure, Pco, cannot be expected in comparison with that in the case of N2 or Ar blowing. Nevertheless, decarburization and deoxidation were observed during rinsing and concentrations of oxygen and carbon after rinsing reduced to those in equilibrium with 0.6 atm of CO. These phenomena cannot be explained by the effect of Pco reduction by bottom blowing gas. On the basis of the experimental results, a new reaction model was proposed by considering the oxygen potential in slag. The model can reasonablly explain the experimental results.
Commercial use of CO gas has been started since 1985 in 180 t combined blowing converter at Mizushima Works, and satisfying results have been obtained.
