无机盐工业
主管:中海油天津化工研究设计院有限公司
主办:中海油天津化工研究设计院有限公司
   中海油炼油化工科学研究院(北京)有限公司
   中国化工学会无机酸碱盐专业委员会
ISSN 1006-4990 CN 12-1069/TQ

无机盐工业 ›› 2025, Vol. 57 ›› Issue (5): 100-107.doi: 10.19964/j.issn.1006-4990.2024-0411

• 环境·健康·安全 • 上一篇    下一篇

电解铝废渣酸浸液结晶分离高纯氯化铝的工艺研究

孙莉萍1(), 成怀刚1,2(), 郭文轩1, 崔莉1   

  1. 1.山西大学资源与环境工程研究所,山西省黄河实验室,山西 太原 030032
    2.青海大学化工学院,青海 西宁 810016
  • 收稿日期:2024-07-18 出版日期:2025-05-10 发布日期:2025-06-05
  • 通讯作者: 成怀刚(1978— ),男,教授,博士生导师,主要研究方向为无机盐资源循环工程;E-mail:chenghg@sxu.edu.cn
  • 作者简介:孙莉萍(2000— ),女,硕士研究生,主要研究方向为电解铝废渣酸浸液的相分离工艺研究;E-mail:313237930@qq.com
  • 基金资助:
    青海省中央引导地方科技发展资金计划项目(2024ZY006);国家自然科学基金项目(U20A20149);青海省基础研究计划项目(2023-ZJ-920M);国家重点研发计划课题(2022YFB4102102);吕梁市校地合作科技成果转化推广项目(2022XDHZ15)

Study on crystallization and separation process of high⁃purity AlCl3·6H2O from acid leach solution of electrolytic aluminum scrap

SUN Liping1(), CHENG Huaigang1,2(), GUO Wenxuan1, CUI Li1   

  1. 1. Institute of Resource and Environmental Engineering,Shanxi University,Shanxi Yellow River Laboratory,Taiyuan 030032,China
    2. College of Chemical Engineering,Qinghai University,Xining 810016,China
  • Received:2024-07-18 Published:2025-05-10 Online:2025-06-05

摘要:

针对电解铝废渣盐酸浸取液中钠、铝元素含量高且难以分离的问题,依据AlCl3-NaCl-H2O(-HCl)体系相图,探讨了酸浸液在不同操作条件下的蒸发结晶规律。通过对比分析溶析结晶与等温蒸发结晶两种技术路线,确定了以等温蒸发结晶为主要路径,旨在实现NaCl与AlCl3·6H2O的精准分离。相图分析结果显示,盐酸浓度对两种盐的溶解度有显著抑制作用,而温度对两种盐的溶解度影响很小。在溶析结晶过程的相图分析中发现,无论是在AlCl3-NaCl共饱点还是酸浸液原料点调整溶液盐酸浓度,所获得的AlCl3·6H2O产品理论纯度均可达到96.65%。在等温蒸发结晶过程中,所获得的产品纯度与溶析结晶过程相同,这为等温蒸发结晶法的应用提供了理论依据。通过对操作性过程进行综合评估得出,该研究采用等温蒸发结晶法作为优选方案。通过等温蒸发结晶法,从复杂酸浸液中直接获得了纯度为99.54%的NaCl和96.22%的AlCl3·6H2O产品,二者的单次收率分别达到94.35%和92.51%。该研究优化了酸浸液钠铝分离的全流程工艺,可借鉴于电解铝废渣资源化利用的工艺设计与过程强化。

关键词: 电解铝废渣, 盐酸浸取液, 结晶分离, 六水氯化铝, 相图

Abstract:

Aiming at the high content of sodium and aluminum elements in the hydrochloric acid leach solution of electrolytic aluminum waste slag and the difficulty of separation,the evaporation and crystallization law of the acid leaching solution under different operating conditions was explored based on the phase diagram of the AlCl3-NaCl-H2O(-HCl) system.By comparing and analyzing the two technical routes of antisolvent crystallization and isothermal evaporation crystallization,the isothermal evaporation crystallization was determined as the main route,aiming at the efficient separation of NaCl and AlCl3·6H2O.The results of phase diagram analysis showed that the acidity had a significant inhibitory effect on the solubility of the two salts,while the temperature had little effect on the solubility of the two salts.During the antisolvent crystallization process,the purity of the obtained AlCl3·6H2O product was close to 96.65%,whether the acidity was adjusted at the co⁃saturation point or the material point.In the isothermal evaporation crystallization process,the purity of the products obtained was similar to that of the antisolvent crystallization process,which provided a theoretical basis for the application of the isothermal evaporation crystallization method.Through a comprehensive evaluation of the operability,isothermal evaporation crystallization was adopted as the preferred solution in this study.The products of NaCl(99.54% in purity) and AlCl3·6H2O(96.22% in purity) were obtained directly from the complex acid leach solution by isothermal evaporation crystallization,and the yield of the them reached 94.35% and 92.51%,respectively.The whole process of sodium⁃aluminum separation from acid leach solution was optimized,which could be applied to the process design and process enhancement for the resource utilization of electrolytic aluminum waste.

Key words: aluminum electrolysis slag, hydrochloric acid leachate, crystallization separation, aluminum chloride hexahydrate, phase diagram

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