三元体系Cd^(2+)∥Cl^-,SO_4^(2-)-H_2O 298K相平衡研究

Phase equilibrium of ternary system Cd^(2+)∥Cl^-,SO_4^(2-)-H_2O at 298K

采用等温溶解平衡法,研究了三元体系Cd2+∥Cl-,SO24--H2O在298 K时的溶解度,测定了平衡液相的密度,折光率和pH值等物化性质,确定了该体系的共饱点组成。该体系属于简单共饱和型,未形成复盐或固溶体。共饱点的固相盐组成为CdCl2·H2O,3CdSO4·8H2O,液相组成为w(CdCl2)38.65%,w(CdSO4)25.40%。CdCl2·H2O和3CdSO4·8H2O 2种盐互有盐析作用。

The solubility and the physical-chemical properties such as density,refractive index,and pH value of the ternary system Cd2＋//Cl-,SO2-4-H2O were studied at 298 K by using an isothermal dissolution equilibrium method.The eutectic point of this system was determined and the phase equilibrium diagram was plotted.This system is of simple common saturation type,no double salt or solid solution was formed.The cosaturated solid salts of eutectic point are CdCl2·H2O and 3CdSO4·8H2O,and the mass fraction composition of the corresponding equilibrium solution is w（CdCl2）=38.65 %,w（CdSO4）=25.40 %.CdCl2·H2O and 3CdSO4·8H2O have mutual salting-out effect.