四元体系NaCl-NaBr-Na_2SO_4-H_2O 348K相平衡研究

Study on Phase Equilibria for Quaternary System of NaCl-NaBr-Na_2SO_4-H_2O at 348 K

采用等温溶解平衡法研究了348 K下四元体系NaCl-NaBr-Na2SO4-H2O的相平衡规律,测定了平衡液相的溶解度和密度。研究发现,四元体系NaCl-NaBr-Na2SO4-H2O是含有固体溶液的体系。根据实验研究数据绘制了等温溶解度图,相图中只有一条单变量溶解曲线,两个结晶相区,平衡固相分别为Na(Cl、Br)和Na2SO4。实验结果表明,NaBr对NaCl具有盐析效应,并简要讨论了密度变化规律。

The phase equilibria of the quaternary system of NaC1 - NaBr - NazSO4 - H20 at 348 K are investigated, and the solubility and density of the solution are determined by isothermal equilibrium method. The experimental results indicate that the quaternary system is the system with solid in the solution. Based on the experimental data, the phase diagram of the quaternary system is plotted, which consists of a univariant dissolution curve and two crystallization fields： Na（Cl,Br） and Na2SO4. The experimental resuhs show that the sodium bromide has the salting - out effect on sodium chloride. Meanwhile, the rule of density is discussed briefly.