A chemical thermodynamics review applied to V2O5 chlorination

This work is mainly related to the thermodynamic study of the V2O5 carbon-chlorination. In this context, three different approaches of diverse complexity level were employed. First, the formation of individual vanadium chlorides and oxychlorides were considered on the basis of the well known ΔG° × T diagrams. It is suggested that these simple constructions can help in understanding the formation sequence of vanadium chlorinated species. Moreover, the relative stability of the most stable vanadium chloride (VCl4) and oxychloride (VOCl3) was addressed based on available thermodynamics data. Finally, a gas phase speciation calculation was performed in order to obtain, simultaneously, the concentration of all possible vanadium chlorides and oxychlorides as a function of temperature, Cl2 and O2 partial pressures. It is demonstrated that, although diverse in the complexity level, the three methods considered have a strong relation with each other, and converge to a better insight into the nature of the chemical equilibrium states achievable for the reaction system under study. The same approach can be applied to any other reaction system of technological importance.