四元体系K_2SO_4-K_2B_4O_7-K_2CO_3-H_2O 273K时介稳相平衡研究  

A STUDY ON METASTABLE EQUILIBRIA OF THE QUATERNARY SYSTEM K_2SO_4-K_2B_4O_7-K_2CO_3-H_2O AT 273 K

作　　者：桑世华[1] 曲树栋[1] 

机构地区：[1]成都理工大学材料与化学化工学院,四川成都610059

出　　处：《矿物岩石》2010年第4期102-105,共4页Mineralogy and Petrology

基　　金：国家自然科学基金(40303010;40973047);教育部新世纪优秀人才资助计划(NCET-07-0125);四川省杰出青年学科带头人培养资助计划(08ZQ026-017)

摘　　要：采用等温蒸发法研究K2SO4-K2B4O7-K2CO3-H2O四元体系在低温273K时的介稳固液相平衡关系,测定了介稳平衡液相的溶解度和密度。研究发现,该四元体系273K时的介稳平衡相图有3个固相结晶相区分别为K2SO4,K2B4O7.4H2O和K2CO3.3/2H2O;3条单变量曲线E1E,E2E和E3E;一个共饱点E,在共饱点E处的液相中各盐的溶解度分别为K2CO3(43.46%),K2SO4(2.52%)和K2B4O7(3.10%);研究结果表明K2CO3对K2B4O7和K2SO4有强烈的盐析作用。实验证明在富含硼钾的扎布耶盐湖卤水中,低温平衡条件下硫酸钾和硼酸钾极易从溶液中结晶析出,而碳酸钾则由于溶解度大,介稳性强,即使在低温条件下也难以从溶液中析出。An experimental study of metastable equilibria of the quaternary system K2SO4-K2B4O7-K2CO3-H2O at 273 K was carried out by isothermal evaporation method.Metastable equilibrium solubility and densities of the solution were determined experimentally.Based on the experimental data,the metastable equilibrium phase diagram and water content diagram were plotted respectively.The phase diagram of the quaternary system has three crystallization fields,corresponding to K2SO4,K2B4O7·4H2O and K2CO3·3/2H2O,three univariant curves（E1E,E2E and E3E）,and one invariant point E.The solubility of the salts of the invariant point E is K2CO3（43.46%）,K2SO4（2.52%）and K2B4O7（3.10%）,respectively.Carbonate potassium（K2CO3）has strong salting-out effect on K2B4O7 and K2SO4.

关 键 词：水盐体系 介稳相平衡 溶解度 钾盐 

分 类 号：O642.42[理学—物理化学]