三元体系Rb^+,Mg^(2+)//SO_4^(2-)-H_2O 298K稳定相平衡研究

Stable Phase Equilibrium in the Ternary System Rb^+, Mg^(2+)//SO_4^(2-) -H_2O at 298 K

采用等温溶解平衡法研究了三元体系Rb^+, Mg^(2+)//SO_4^(2-)-H_2O 298 K下的稳定相平衡,测定了该体系平衡液相组成和密度,确定了平衡固相组成及存在形式。根据试验数据绘制了该三元体系的稳定相图和密度-组成图。结果表明:该三元体系在298 K时有复盐Rb_2SO_4·MgSO_4·6H_2O生成,为复杂三元体系。其稳定相图包含有2个三元共饱点、3条单变量曲线和3个结晶区。2个共饱点均为相称共饱点;3个结晶区分别为单盐MgSO_4·7H_2O、Rb_2SO_4和复盐Rb_2SO_4·MgSO_4·6H_2O的结晶区。此外,采用经验方程式计算了该三元体系的密度,计算值与试验值显示了良好的吻合度,相对误差小于1%。

Isothermal dissolution method was employed to study the ternary system Rb^+,Mg^2+//SO4^2--H 2O at 298 K,the composition and density of the equilibrium liquid phase as well as the composition and existing form of the equilibrium solid phases were determined.According to the experimental data,the stable phase diagram and the density versus composition diagram in the ternary system were plotted.The results show that the ternary system Rb^+,Mg^2+//SO4^2--H 2O at 298 K is a complex one in which the double salt Rb 2SO 4·MgSO 4·6H 2O is formed.The stable phase diagram contains two invariant points(commensurate type saturation points),three univariant curves,and three crystallization fields corresponding to single salt MgSO 4·7H 2O,Rb 2SO 4 and commensurate double salt Rb 2SO 4·MgSO 4·6H 2O.Moreover,the density of the solution in the ternary system was calculated using the classical equation,and the calculated value shows good agreement with the experimental value with the relative error less than 1%.