Activity Calculation by Application of Sub-Regular Solution Model in Binary Oxide Systems

Abstract

To confirm sub-regular solution model valid for predicting the activity of component in binary oxide systems, seven systems in the whole concentration and twelve systems presenting saturation concentration have been studied. The total average relative errors of component 1 and 2 are 3.2% and 4.1% respectively by application of the sub-regular solution model into the systems within the whole concentration. However, the total average relative errors are 16% and 1088% in the systems presenting saturation concentration. The results show that sub-regular solution model is not good for predicting the systems presenting saturation concentration, especially for the systems containing acidic or neutral oxide. The reason may be that the influence of the two types of oxide on the configuration is greater in binary oxide systems. These oxides can be present in the form of complex anion partly, Si-O, Al-O, Ti-O and so on, for example (SiO4)4−. That is contrary to sub-regular solution model which is supposed that the oxide systems consist of cation and O2−. But compared with regular solution model and quasi-regular solution model, sub-regular solution model is closer to the characteristics of actual solution and the calculated results are superior.