Based on the molecular interaction volume model(MIVM) and the coexistence theory model,the component activities were predicted in the ternary slags Fe0-Mn0-SiOz,Fe0-Mn0-TiOz,Mn0-SiOz-TiOzand Fe0-SiOz-TiOz .In com parison with the experiment data,the total average relative errors of the predicted value by pseudo-multicomponent approach of MIVM were 16%,the total average standard deviations were 0. 062. On the other hand,the total average relative errors of the predicted value by coexistence theory model were 28%,the total average standard deviations were 0.  077. The prediction effect of the pseudo-multicomponent approach of MIVM has better stability and reliability than coexistence theory. the activities of component TiOzwere predicted in the ternary slags Fe0-Mn0TiOz,Mn0-SiOz-TiOzand Fe0-SiOz-TiOz by MIVM,draw its isoactivity curve,the thermodynamic behavior tendency of constituent TiOz in different slag systems was analyzed.

titanium oxide, molten  , slags, activity, prediction, pseudo-multicomponent approach , of MIVM