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›› 2007, Vol. 7 ›› Issue (5): 934-938.

• 反应与分离 • 上一篇    下一篇

氯化钾与五硼酸钠复分解反应制备五硼酸钾的动力学

张金平,孙勇,杨刚,李佐虎   

  1. 中国科学院过程工程研究所
  • 出版日期:2007-10-20 发布日期:2007-10-20

Kinetics of Replacement Reaction between Potassium Chloride and Sodium Pentaborate for Preparing Potassium Pentaborate

ZHANG Jin-ping,SUN Yong,YANG Gang,LI Zuo-hu   

  1. Institute of Processing Engineering，Chinese Academy of Sciences
  • Online:2007-10-20 Published:2007-10-20

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摘要： 研究了利用氯化钾晶体和五硼酸钠溶液的复分解反应制备五硼酸钾的方法. 考察了五硼酸钠溶液浓度、反应温度和反应物摩尔配比(KCl:NaB5O8)对五硼酸钾结晶率的影响，结果表明，五硼酸钠溶液浓度是影响反应的最主要因素，反应温度和反应物摩尔配比的影响次之. 采用选取控制步骤法并引入修正的Debye-Hückel活度系数模型和Bromley渗透系数模型研究了该反应的动力学的影响规律，得出反应级数为2，表观反应活化能为85.8 kJ/mol，反应主要受四水五硼酸钾晶体析出的控制.

关键词: 氯化钾, 五硼酸钠, 复分解反应, 五硼酸钾, 反应动力学

Abstract: The preparation method of potassium pentaborate (KB5O8) was studied with the replacement reaction between potassium chloride and sodium pentaborate solution. The effects of sodium pentaborate concentration, reaction temperature and reactant mole ratio (KCl:NaB5O8) on the crystallization rate of KB5O8 were investigated. The results show that sodium pentaborate concentration is the most influential factor for affecting the reaction, while reaction temperature and reactant mole ratio (KCl:NaB5O8) are secondary factors. The reaction kinetics was studied by selecting control-step method as well as modified Debye-Hückel activity coefficient model and Bromley osmotic coefficient model. The results show that the reaction order is 2 and apparent reaction activation energy 85.8 kJ/mol, and the reaction is mainly controlled by precipitation of KB5O8×4H2O.

Key words: potassium chloride, sodium pentaborate, replacement reaction, potassium pentaborate, reaction kinetics