Extraction of Lithium from Magnesium-Rich Solution Using Tri-n-butyl Phosphate and Sodium Hexafluorophosphate

Ionic liquids (ILs) such as 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4 mim][PF 6 ]) are considered suitable co-extraction reagents of tri- n -butyl phosphate (TBP) for selective extraction of lithium from magnesium-rich salt lake brine. However, ILs are very expensive and the loss of cati...

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Bibliographic Details
Published inJournal of sustainable metallurgy Vol. 7; no. 3; pp. 1368 - 1378
Main Authors Zhou, Wanji, Li, Zheng, Xu, Shiai
Format Journal Article
LanguageEnglish
Published Cham Springer International Publishing 01.09.2021
Springer Nature B.V
Subjects
Aqueous solutions
Brines
Earth and Environmental Science
Environment
Fourier transforms
Hydrochloric acid
Hydrogen chloride
Infrared analysis
Infrared spectroscopy
Inorganic salts
Ionic liquids
Lithium
Magnesium chloride
Metallic Materials
Phase ratio
Reagents
Regeneration
Research Article
Salt lakes
Sodium carbonate
Sustainable Development
butyl phosphate
Stripping
Sodium hexafluorophosphate
Lithium extraction
Salt lake brine
Tri
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Summary:Ionic liquids (ILs) such as 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4 mim][PF 6 ]) are considered suitable co-extraction reagents of tri- n -butyl phosphate (TBP) for selective extraction of lithium from magnesium-rich salt lake brine. However, ILs are very expensive and the loss of cations can cause the contamination of the aqueous solution. The corresponding inorganic salts of ILs such as sodium hexafluorophosphate (NaPF 6 ) should play the same role as ILs in the extraction of Li + by TBP, and importantly, they are cheaper and more environmentally friendly. In this study, the effects of NaPF 6 concentration, phase ratio, initial pH of the aqueous phase, temperature, and MgCl 2 concentration on the extraction of lithium were investigated. It was found that NaPF 6 was as good as [C 4 mim][PF 6 ] in the extraction of Li + from Mg-rich solution by TBP, and their extraction mechanisms are also the same, which is certified by comparing the Fourier transform infrared spectroscopy (FT-IR) and slope analysis. Hydrochloric acid (HCl) is more effective than sodium carbonate (Na 2 CO 3 ) in the stripping of Li + , but Na 2 CO 3 can avoid the regeneration of the organic phase and increase the reusability of both TBP/[C 4 mim][PF 6 ] and TBP/NaPF 6 systems. Graphical Abstract In TBP/NaPF 6 system, the schematic of Li extraction/stripping from brine with high Mg/Li ratios using (a) HCl as stripping agent and (b) Na 2 CO 3 as stripping agent
ISSN:2199-3823
2199-3831
DOI:10.1007/s40831-021-00430-7