Abstract: It is the major factor that combustion reaction of the return of oxygen in chlorine with petroleum coke affecting the temperature of molten salt chlorinator by calculation and analysis of carbochlorination thermodynamic of all oxides of titania-rich slag, temperature stability controlling is the key to further improve the operational efficiency of molten salt chlorinator;the thermodynamics trends of carbochlorination of titania-rich slag suggest that all of the oxides would be chlorinated into chloride during 900~1 500 K, while Al₂O₃ and SiO₂ in particular are very limited in fact, the order of carbochlorination of all oxides is determined and the chlorination rate of TiO₂ and SiO₂ is the same.So in terms of thermodynamics it is so hard to low the rate of chlorination of SiO₂ further to reduce the content of Si in TiCl₄.