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过程工程学报 ›› 2020, Vol. 20 ›› Issue (3): 318-323.DOI: 10.12034/j.issn.1009-606X.219223

• 反应与分离 • 上一篇    下一篇

AlCl3–FeCl3–HCl–H2O体系的相平衡及相分离

仵理想1， 赵 静1,2， 薛芳斌1， 成怀刚1*， 程芳琴1   

  1. 1. 山西大学资源与环境工程研究所，山西低附加值煤基资源高值利用协同创新中心，山西 太原 030006 2. 山西职业技术学院材料工程系，山西 太原 030006
  • 收稿日期:2019-06-06 修回日期:2019-07-09 出版日期:2020-03-22 发布日期:2020-03-20
  • 通讯作者: 成怀刚 chenghg@sxu.edu.cn
  • 基金资助:
    国家重点研发计划;国家自然科学基金;山西省“三晋英才”计划

Phase equilibrium and separation of AlCl3–FeCl3–HCl–H2O system

Lixiang WU1, Jing ZHAO1,2, Fangbin XUE1, Huaigang CHENG1*, Fangqin CHENG1   

  1. 1. Institute of Resources and Environmental Engineering, State Environmental Protection Key Laboratory on Efficient Resource Utilization Techniques of Coal Waste, Shanxi University, Taiyuan, Shanxi 030006, China 2. Materials Engineering Department, Shanxi Polytechnic College, Taiyuan, Shanxi 030006, China
  • Received:2019-06-06 Revised:2019-07-09 Online:2020-03-22 Published:2020-03-20
  • Contact: Huaigang Cheng chenghg@sxu.edu.cn
  • Supported by:
    National Key Research and Development Program of China

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摘要： 为从含铝铁粉煤灰酸浸液中提取高纯AlCl3?6H2O，在温度20和30℃下采用等温溶解平衡法测定了H+浓度1.3 mol/L的AlCl3–FeCl3–HCl–H2O体系的相平衡数据，绘制了该体系的相图和密度?组成图，根据相图分析了酸浸液等温蒸发的路径。结果表明，20和30℃下该体系均属于简单共饱和体系，不产生复盐和固溶体。随温度升高，FeCl3的溶解度由43.59%增大至49.34%，AlCl3的溶解度约稳定在30.70%，且FeCl3?6H2O的结晶区减小、AlCl3?6H2O的结晶区相对增大。从模拟铝铁酸浸液中直接分离出了纯度为96.61%的AlCl3?6H2O。

关键词: 关键词：相平衡, 溶解度, 相图, 等温蒸发, 六水氯化铝, 六水氯化铁。

Abstract: In order to extract high purity AlCl3?6H2O from acid leaching solution of aluminum/iron-containing fly ash, it is necessary to determine the phase equilibrium data of AlCl3–FeCl3–HCl–H2O quaternary system under acidic condition. The phase equilibrium data of the AlCl3–FeCl3–HCl–H2O system with H+ concentration of 1.3 mol/L at 20 and 30℃ were determined using the isothermal dissolution equilibrium method. The phase diagrams and density?composition charts of the system were drawn. The results showed that the salt?water system was simply co-saturated at 20 and 30℃, and there was not any double salt and solid solution. The density of saturated solution increased gradually with the increase of FeCl3 concentration, and finally tended to be stable. After reaching the co-saturation, the density of solution at 30℃ was obviously higher than that of solution at 20℃. With the increase of temperature, the solubility of FeCl3 increased from 43.59% to 49.34%, the solubility of AlCl3 was about 30.70%, which was almost unchanged. It was also found that the crystallization zone of FeCl3?6H2O decreased and the crystallization zone of AlCl3?6H2O increased. According to the AlCl3–FeCl3–HCl–H2O phase diagram, the isothermal evaporation route analysis of the acid leaching liquor was carried out. The simulated acid leaching solution of aluminum and iron was used to evaporate and crystallize. The purity of AlCl3?6H2O directly separated from acid leaching solution reached 96.61%, and the recovery rate was 75.88%. Then the acid leaching liquor with different iron content was added to evaporate and crystallize, and the products were compared and analyzed. It was found that the purity of the product increased gradually with the decrease of iron content in the feed acid leaching liquor. When the contents of AlCl3 and FeCl3 in solution were 14.83% and 0.33%, the purity of AlCl3?6H2O crystals reached 99.61%, with the decrease of iron content in acid leaching solution, the purity of crystalline products was higher.

Key words: Phase equilibrium, Solubility, Phase diagram, Isothermal evaporation, Aluminum chloride hexahydrate, ferric chloride hexahydrate.