采用等温溶解平衡法研究Na2B4O7 -NaBr-Na2SO4-H2O四元体系在348 K的相平衡关系,测定了平衡液相的溶解度和密度.根据实验数据绘制相应相图.该四元体系相图中有1个共饱点E,3条单变量曲线E1E,E2E,E3E,3个结晶区的平衡固相分别为:NaBr,Na2SO4和Na2B4O7 · 5H2O.研究结果表明:该四元体系无复盐和固溶体生成,属于简单四元体系,NaBr对Na2B4O7·5H2O和Na2SO4有较强的盐析作用.并对NaBr和Na2B4O7在不同温度下含有的结晶水数进行了对比分析,简要讨论了密度变化规律.%The solubilities and densities of solution in Na2B4O7-NaBr- Na2SO4-H2O quaternary system at 348 K were determined by isothermal equilibrium method. Based on the experimental data, the equilibrium phase diagram was plotted, which consists of one invariant E, three univariant curves (E1E, E2E and E3E) , and three crystallization fields corresponding to NaBr, Na2SO4 and Na2B4O7 ? 5H2O. The experimental results indicate that the quaternary system is of simple eutectic type and no double salt and solid solution, and sodium bromide has the salting-out effect on Na2B4O7 ? 5H2O and Na2SO4. The densities transformation rules were discussed.
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