Phase Equilibria in the Ternary Systems KBr–K_2B_4O_7–H_2O and KCl–K_2B_4O_7–H_2O at 373 K  

作　　者：CUI Ruizhi SANG Shihua HU Yongxia HU Jiawen 

机构地区：[1]College of Materials, Chemistry & Chemical Engineering, Chengdu University of Technology [2]State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology [3]Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institutions [4]College of Resources, Shijiazhuang University of Economics

出　　处：《Acta Geologica Sinica(English Edition)》2013年第6期1668-1673,共6页地质学报（英文版）

基　　金：supported by the Open Fund (PLC201204) of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Chengdu University of Technology);the National Natural Science Foundation of China (Grant No. 41373062,40973047, 41172118);the Specialized Research Fund (20125122110015) for the Doctoral Program of Higher Education of China;the youth science and technology innovation team of Sichuan Province, China(2013TD0005)

摘　　要：According to the compositions of the underground gasfield brines in the west of Sichuan Basin,the phase equilibria in the ternary systems KBr-K2B4O7-H2O and KCl-K2B4O7-H2O at 373 K were studied using the isothermal dissolution equilibrium method.The solubilities of salts and the densities of saturated solutions in these ternary systems were determined.Using the experimental data,phase diagrams and density-composition diagrams were constructed.The two phase diagrams were simple co-saturation type,each having an invariant point,two univariant curves and two crystallization regions.The equilibrium solid phases in the ternary system KBr-K2B4O7-H2O are potassium bromide （KBr） and potassium tetraborate tetrahydrate （K2B4O7·4H2O）,and those in the ternary system KCl-K2B4O7-H2O are potassium chloride （KCl） and potassium tetraborate tetrahydrate （K2B4O7·4H2O）.Comparisons of the phase diagrams of the two systems at different temperatures show that there is no change in the crystallization phases,but there are changes in the size of the crystallization regions.As temperature increases,the solubility of K2B4O7·4H2O increases rapidly,so the crystallization field of K2B4O7·4H2O becomes smaller.According to the compositions of the underground gasfield brines in the west of Sichuan Basin,the phase equilibria in the ternary systems KBr-K2B4O7-H2O and KCl-K2B4O7-H2O at 373 K were studied using the isothermal dissolution equilibrium method.The solubilities of salts and the densities of saturated solutions in these ternary systems were determined.Using the experimental data,phase diagrams and density-composition diagrams were constructed.The two phase diagrams were simple co-saturation type,each having an invariant point,two univariant curves and two crystallization regions.The equilibrium solid phases in the ternary system KBr-K2B4O7-H2O are potassium bromide （KBr） and potassium tetraborate tetrahydrate （K2B4O7·4H2O）,and those in the ternary system KCl-K2B4O7-H2O are potassium chloride （KCl） and potassium tetraborate tetrahydrate （K2B4O7·4H2O）.Comparisons of the phase diagrams of the two systems at different temperatures show that there is no change in the crystallization phases,but there are changes in the size of the crystallization regions.As temperature increases,the solubility of K2B4O7·4H2O increases rapidly,so the crystallization field of K2B4O7·4H2O becomes smaller.

关 键 词：Underground brine phase equilibrium SOLUBILITY potassium salt BORATE 

分 类 号：P595[天文地球—地球化学]