Acta Phys. -Chim. Sin. ›› 1994, Vol. 10 ›› Issue (06): 536-542.doi: 10.3866/PKU.WHXB19940611

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A Study on the Ternary Systems Li+, K+(Mg2+)/SO2-4-H2O at 25 ℃

Li Bing, Wang Qing-Zhong, Li Jun, Fang Chun-Hui, Song Peng-Sheng   

  1. Institute of Salt Lakes, Academia Sinica, Xining 810008
  • Received:1993-03-19 Revised:1993-07-12 Published:1994-06-15
  • Contact: Song Peng-Sheng

Abstract:

Solubilities of the ternary systems Li~+, K~+/SO_4~(2-)-H_2O (1) and Li~+, Mg~(2+)/SO_4~(2-)-H_2O (2) were investigated by isothermal method at 25 ℃. Physico-chemical properties of solutions, such as density, refractive index, viscosity, conductivity, and pH, were determined. Phase diagram of the system (1) consists of three sollubility branches and three crystallization fields corresponding to K_2SO_4, LiKSO_4, and Li_2SO_4·H_2O. LiKSO_4 is an incongruent compound, and its transition poin is 45.5~46.0 based on our graphical estimate. No solid solution of LiKSO_4 with Li_2SO_4·H_2O was found in the system. System (2) is of a simple eutonic type. Pitzer model of electrolyte solution was used to check the obtained solubilities. Data comparison gives good agreement. Physico-chemical properties of solutions, such as density, refractive index, viscosity, conductivity, pH, and X-ray diffraction, IR spectra, DTA of LiKSO_4 were measured. Two equations were used to correlate density, refractive index with copmposition. Differences between measured and calculated values are less than 0.6% for density, 0.15% for the later.

Key words: Salt-water system, Solubility, Phase equilibrium, Li compound