イルメナイト固溶体(Fe2+, Mn2+, Mg)TiO3と(Fe2+, Mn2+, Mg)Cl2水溶液間におけるイオン交換平衡実験

Abstract

Ion exchange experiments between ilmenite solid solution (Fe2+, Mn2+, Mg)TiO3 and 1 molal aqueous (Fe2+, Mn2+, Mg)Cl2 solution were carried out using standard cold-seal type pressure vessels at 600°C and 1000kg/cm2. The ion exchange reactions can be expressed as follows;FeTiO3+MnCl2aq=MnTiO3+FeCl2aqMnTiO3+MgCl2aq=MgTiO3+MnCl2aqand MgTiO3+FeCl2aq=FeTiO3+MgCl2aq. Under the experimental conditions, FeTiO3, MnTiO3 and MgTiO3 make a perfectly continuous solid solution. Based on thermodynamic analysis using ternary solid solution model of Kakuda et al. (1991), interaction parameters (Wi) for the ternary ilmenite solid solution have been obtained to be WFeFeMn=-0.02, WFeMnMn=-0.19, WMnMnMg=2.99, WMnMgMg=3.34, WMgMgFe=1.23, WMgFeFe=1.03 and WFeMnMg=1.83kcal/mol. FeTiO3-MnTiO3 solid solution is regarded as ideal solution, and MnTiO3-MgTiO3 and MgTiO3-FeTiO3 solid solutions show positive deviations from ideal solution. Ferrous ion is preferably partitioned into ilmenite solid solution. On the other hand, manganese ion tends to concentrate into aqueous chloride solution.