| Recently, inorganic salt-mixed solvent is becoming an important system for solution. Accordingly, the phase relationship research for such system can not only rich chemical solution, but also may provide new ideas for separation and purification of salts, particularly the precious metals.This research work mainly includes three sections: the first chapter was a review, the second chapter was experimental part, and the third were research results and discussion.In the review, the basic knowledge of rubidium, cesium and their compounds was introduced firstly. Then we presented the investigation of inorganic salts-mixed solvent systems and the importance was paid on the systems of alkali and rare alkali metal salts.The experimental part gave the specific methods and operations.The research results and discussion part mainly contain three subunits: Firstly, we studied the phase equilibrium situation of KCl+CsCl+ROH(R=CH3-, C2H5-, 1-C3H7-)+H2O quaternary systems at 25℃, 35℃and 45℃, as well as KCl+CsCl+2-C3H7OH+H2O system at 25℃. The experimental results showed that all 1-C3H7OH systems appeared in two liquid phases: alcoholic phase and water phase. Forthermore, we have performed the salts of different ratios and temrerature effects on liquid-liquid region. At the same time, we have got the compositions of three sectional phases, as well as the whole phase diageams of them at differert temperatures. The experimental results also showed that 2-C3H7OH system had similar experiment phenomenon to 1-C3H7OH system, this experiment also investigated the polarity of organic solvent on the liquid-liquid equilibrium. For KCl+CsCl+C2H5OH+H2O quaternary system, it was found that the range of demixing is gradually increasing with the increasing of temperature. However, there only two phases, water phase and solid phase for KCl+CsCl+CH3OH+H2O system within the experimental temperature range. With the increasing of organic solvent, potassium chloride and cesium chloride were gradually decreased. In the second part, we used the same experimental apparatus and similar methods to study the phase behavior of NaCl+CsCl+ROH(R=CH3-, C2H5-, 1-C3H7-, 2-C3H7-)+H2O systems at 25℃and NaCl +CsCl+ROH(R=CH3-, C2H5-)+H2O systems at 35℃. The results gave us the similar phenomena to the potassium-salt systems except the NaCl+CsCl+C2H5OH+H2O system, which wasn't demixed at 25℃, however, it appeared three phases when the temperature was 35℃.For all systems with three phases, the tie-line data were correlated using a modified Eisen-Joffe equation, and it was used to investigate the effect of two different salts on the liquid-liquid equilibrium.The standard deviations show that the results are satisfactory. The binodal curve data were fitted with a five-parameter equation, which also has a satisfactory result. Finally, the reliability of the tie-line data was verified by Othmer-Tobias equation and Bancroft's equation.In the last part, we made an explanation for the mechanism of liquid-liquid equilibrium.In this thesis, a series of phase equilibrium data of quaternary systems made by (potassium, cesium) salts-mixed solvent and (sodium, cesium) salts-mixed solvent were given out, the experimental results provided not only basic thermodynamic data for solution chemistry, but also new purification methods for inorganic salts and the partition of materials. |
PDF Full Text Request