(1. 鄭州大學 化工學院，鄭州 450001；
2. 鄭州大學 材料科學與工程學院，河南省資源與材料工業(yè)技術(shù)研究院，鄭州 450001)
摘 要: 熔鹽電化學工藝是提取與提純金屬鈦最具前景的方法。鈦離子活度的確定對研究鈦的熔鹽電解機制具有重要意義。因此，為得到熔鹽中二價鈦離子濃度與其活度的關(guān)系，本文采用開路電位法在三電極體系下測定了含定量鈦離子及飽和金屬鈦的NaCl-KCl共晶鹽中的離子平衡電位，并由Nernst方程計算得出二價鈦離子的活度，進而獲得了對應的活度因子。結(jié)果表明：在1023 K下，當熔鹽中二價鈦離子摩爾分數(shù)介于0.296%~2.378%時，其活度值單調(diào)地介于0.00205~0.01877，且其活度因子為0.693~0.998。本研究可為精確確定熔鹽中鈦離子活度及進一步研究鈦離子歧化反應的平衡常數(shù)提供重要基礎。
關(guān)鍵字: 二價鈦離子；熔鹽；活度；開路電位法
（1. School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China;
(2. School of materials science and Engineering, Henan Province Industrial Technology Research Institute of Resources and Materials, Zhengzhou University, Zhengzhou 450001, China）
Abstract:Molten salt electrochemical process is the most promising method to extract and purify titanium. The determination of titanium ions activities is of great significance to the study of molten salt electrolysis mechanism of titanium. Therefore, in order to obtain the relationship between the concentration of divalent titanium ion and its activity in molten salt, the ions equilibrium potentials of NaCl-KCl eutectic salt system containing quantitative titanium ions and saturated metal titanium were measured by open circuit potential method in three-electrodes system. The activity of divalent titanium ion was calculated by Nernst equation, and the corresponding activity coefficient was obtained. The results show that the activity values of divalent titanium ions are monotonically ranged from 0.205 and 1.877, the activity coefficients range from 0.693 to 0.998, when the molar fraction of titanium ions ranges from 0.296% to 2.378% at 1023 K. This study can provide an important basis for accurately determining the activity of titanium ion in molten salt and further studying the equilibrium constant of titanium disproportionation reaction.
Key words: divalent titanium; molten salt; activity; open circuit potential method
