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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Published in | Journal of sustainable metallurgy Vol. 7; no. 3; pp. 1368 - 1378 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Cham
Springer International Publishing
01.09.2021
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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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 |
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ISSN: | 2199-3823 2199-3831 |
DOI: | 10.1007/s40831-021-00430-7 |