化工学报2016，Vol.67Issue(4)：1123-1128,6.DOI:10.11949/j.issn.0438-1157.20151183
四元体系Na+,K+//Br-,SO42--H2O 373 K相平衡
Phase equilibria in quaternary system Na+,K+//Br-,SO42--H2O at 373 K
摘要
Abstract
According to the composition of the brine resources in the west of Sichuan Basin, phase equilibria in the quaternary system Na+,K+//Br−,SO42−-H2O at 373 K is measured by the isothermal solution saturation method, and the solubilities and densities of the solution are determined experimentally. Using the experimental results, the dry salt phase diagram, water diagram and the densities versus composition diagram are obtained. In the phase diagram of quaternary system Na+,K+//Br−,SO42−-H2O at 373 K, the double salt Na2SO4·3K2SO4 is found. There are three invariant points, seven uninvariant curves and five crystallization fields in the quaternary system. The five crystallization fields correspond to NaBr, Na2SO4, K2SO4, KBr and Na2SO4·3K2SO4(Gla), respectively. The crystallization field of NaBr has the smallest crystallization area, whereas the double salt Na2SO4·3K2SO4(Gla) has the biggest crystallization field in the quaternary system. It means that the double salt Na2SO4·3K2SO4(Gla) has the smaller solubility, and it can be easiest separated from solution. Compared with the two phase diagrams of quaternary system Na+,K+//Br−,SO42−-H2O at 323 K and 373 K, the result shows that the numbers of invariant points, crystallization fields and unvariant curves are the same. The double salt all forms in the phase diagrams of quaternary systems at two different temperatures. But univariant curve GH of the corresponding balance solid phase is different and the crystal water of sodium bromide has disappeared at 373 K. In comparison with the quaternary system Na+,K+//Cl−,SO42−-H2O and the quaternary system Na+,K+//Br−,SO42−-H2O at 373 K, the two phase diagrams have very similar shapes, each of them having three invariant points, seven univariant curves and five crystallization fields. The crystallization field of the salt NaBr is apparently smaller than that of NaCl. It is also found that halide has the salting-out effect on sulfates. The water content and the density transformation rules are discussed simply. The water content is lower with the higher solution of bromine and the density is higher with the higher solution of bromine.关键词
地下卤水/相平衡/溶解性/溶液/钾盐/溴盐Key words
underground brine/phase equilibria/solubility/solution/potassium salt/bromine salt分类
化学化工引用本文复制引用
崔瑞芝,桑世华..四元体系Na+,K+//Br-,SO42--H2O 373 K相平衡[J].化工学报,2016,67(4):1123-1128,6.基金项目
国家自然科学基金项目(41373062)；高等学校博士学科点专项科研基金项目(20125122110015)；四川省高校科研创新团队项目(15TD0009)。@@@@supported by the National Natural Science Foundation of China (41373062), the Specialized Research Fund for the Doctoral Program of Higher Education of China (20125122110015) and the Scientific Research and Innovation Team in Universities of Sichuan Provincial Department of Education(15TD0009) （41373062）
