Extraction of zinc(II) from ammoniacal solution into hydrophobic ionic liquids

Authors

  • Jiugang Hu,

    1. Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education; College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
    Search for more papers by this author
  • Qiyuan Chen,

    Corresponding author
    1. Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education; College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
      Qiyuan Chen, Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education; College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. E-mail: cqy@csu.edu.cn
    Search for more papers by this author
  • Huiping Hu,

    1. Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education; College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
    Search for more papers by this author
  • Qian Ma,

    1. Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education; College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
    Search for more papers by this author
  • Zhoulan Yin,

    1. Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education; College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
    Search for more papers by this author
  • Fengchun Hu

    1. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
    Search for more papers by this author

Qiyuan Chen, Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education; College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. E-mail: cqy@csu.edu.cn

Abstract

BACKGROUND: Separation and recovery of zinc from ammoniacal solutions with solvent extraction is very important in the hydrometallurgical industry. Ionic liquids (ILs) have considerable potential for the separation of metal ions. The extraction behaviour of zinc from ammoniacal solution into three hydrophobic ILs was investigated using β-diketone as the extractant.

RESULTS: The extraction efficiency of zinc for three ILs reached a maximum at pH 7.5 and subsequently decreased with increase of pH and it also decreases with increase of the total ammonia concentration. The overall extraction process is exothermic. The extractability decreases in the IL order: [BMIM]NTf2 > [OMIM]PF6 > [OMIM]NTf2. The results of X-ray absorption spectra indicate that the coordination number of the extracted zinc complexes decreases with increase in the hydrophobicity of the ILs. The results of five recycling experiments indicate that the three hydrophobic ILs are more stable than [BMIM]PF6 for the extraction of zinc in ammoniacal solutions.

CONCLUSION: Hydrophobic ILs combined with β-diketone can be used to extract zinc from ammoniacal solutions. The extraction of zinc is dependent on the zinc species in ammoniacal solutions and the hydrophobicity of ILs. Moreover, the latter affects both the extractability of extraction systems and the structure of the extracted complexes. © 2012 Society of Chemical Industry

Ancillary