Advanced Materials Research
ISSN: 1662-8985, Vols. 602-604, pp 1335-1338
doi:10.4028/www.scientific.net/AMR.602-604.1335
© 2013 Trans Tech Publications, Switzerland
Online: 2012-12-13
Research on Preparing Lithium Carbonate by Carbonation from Lithium
Chloride in Biphase System
Wang Changqing*
Key Laboratory of Jiangxi University for Applied Chemistry and Chemical Biology, College of
Chemistry and Bio-engineering, Yichun University, Yichun 336000, China
[email protected]
Keywords: Lithium chloride, lithium carbonate, n-butanol, carbonation process
Abstract. A process has been proposed for carbonation and recovery of lithium carbonate from
lithium chloride. Based on distribution coefficients, separation factors of the results, lithium chloride
extraction with n-butanol has also been studied. The purity of this lithium carbonate product was as
high as 99.6 %.
Introduction
Lithium is found in lake brines, seawater, oil residues, minerals and clays.[1] The commercial
sources of lithium are minerals, brines and seawater and the lithium minerals of economic importance
are spodumene (LiAlSi2O6), petalite (LiAlSi4O10), lepidolite ((Li,Al)3(Al,Si)4O10(F,OH)2), and etc.[2]
Among all lithium compounds, lithium carbonate is the precursor for other lithium metal
production.[3] Its oldest application is in the glass and ceramic industry. The addition of lithium
carbonate in glass and ceramic production lowers the process melting point, reduces energy
consumption, increases furnace refractory life, improves the strength of the glass product, reduces the
coefficient of thermal expansion as well as viscosity.[4] Lithium and its compounds have recently
found use in energy storage devices such as rechargeable lithium-ion batteries.[5-7] It was reported that
the global market for lithium-ion batteries has increased by more than 20% per year in the past few
years and that the use of lithium batteries in upcoming electric and hybrid vehicles could further
increase demand for the metal.[8]
The growing demand for lithium to meet the raw material needs of the energy storage devices is
one of the reasons for studying the upgrading of Yichun lepidolite into lithium carbonate.[9] The
purpose of this study was to develop a simple procedure for the preparation of lithium carbonate from
extracted lithium chloride and for the winning of a pure lithium compound. The work presented here
gives detailed data on the solution purification, and precipitation of lithium carbonate from lithium
chloride by reaction with ammonium carbonate in n-butanol.
2. Materials and methods
2.1. Materials
The alkali chlorides (LiC1, NaC1, and KC1) and the alkaline earth chloride (CaC12) used in this
study were analytically pure products procured from Sichuan Tianqi Lithium Industries, Inc.
n-butanol was obtained from Sinopharm Chemical Reagent Co,Ltd. Distilled water was used in the
preparation of all aqueous solutions.
2.2. Experimental procedure
2.2.1 Decalcification process
This study discusses the conditions such as temperature, PH, the amount of lithium oxalate and
stirring rate which affect on decalcification rate. A saturated solution of lithium oxalate was added
drop-wise to the aqueous of lithium chloride giving a white precipitate of calcium oxalate, which was
All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans
Tech Publications, www.ttp.net. (#69813320, Pennsylvania State University, University Park, USA-18/09/16,12:38:52)
1336
Progress in Materials and Processes
removed by filtration. The flow sheet of the purification procedure is shown in Figure 1. After
filtration, a sample from the filtrate was then completely evaporated and the residue was analyzed.
Reproducibility of the process was tested by running the experiments in triplicate. Errors for each
were below 3%.
2.2.2 Carbonation and recovery of lithium from lithium chloride
The aqueous phase was then concentrated to a saturated solution and n-butanol was added to the
concentrated liquor to extract lithium chloride. In this case, lithium chloride was extracted into
organic phase and good separation of sodium and potassium was possible. Pour the mixture into a
separatory funnel and the aqueous layer was removed and then a saturated solution of ammonium
carbonate was added little by little to the organic solution at ambient temperature. At this process
lithium carbonate was precipitated and the cake was filtered and washed with water. The
water-washed lithium carbonate was dried at 250 °C. Ammonium chloride in the mother liquor was
crystallized by chilling the solution at 0 - 8 °C followed by filtration. The filtrate which contains some
lithium and residual ammonium chloride was recycled to the evaporator.
Figure 1. Flow sheet for purification of Li2CO3.
3. Result and discussion
3.1. The influence of lithium oxalate on decalcification rate
The chemical composition of raw lithium chloride is provided in Table 1. In the experiments, the
effect of lithium oxalate on decalcification was investigated in water at room temperature. An
aqueous lithium solution composed of lithium chloride (2.5 M) was reacted with lithium oxalate. The
precipitation time was 1h and the PH value was controlled at about 8. It is indicated from Figure 2 that
lithium oxalate is effective in removing calcium by precipitation. Calcium oxalate is precipitated
from an aqueous lithium solution using lithium oxalate according to the following reaction (1):
Analytical results show that the calcium impurity content in solution could be controlled to 10 x
10 % when 0.5 % lithium oxalate was added.
-6
Table 1 Content of impurities in raw lithium chloride
Component
Content (%)
Na
0.1
K
0.1
Ca
0.05
Mg
0.01
Figure 2 Effect of lithium oxalate on decalcification rate
Fe
0.002
Advanced Materials Research Vols. 602-604
1337
3.2. Effect of extraction by n-butanol
The influence of n-butanol on the distribution coefficient, D, and the separation factor, S, were
studied with simple salt, molar solutions of lithium, sodium and potassium chlorides. The organic to
aqueous phase ratio was 1:1, the initial pH of the aqueous feed was 7. The results are summarized in
Table 2. The extractant contained strongly polar and electronegative atoms. The electronegativity of
the extract may play an important role in the establishment of the equilibrium concentrations:
where M represents Li, Na and K. One can anticipate that the strongest electropositive metal ion (Li+)
will be attracted preferentially by the electronegative solvent. In these series of experiments the
excellent results were obtained with n-butanol.
Table 2 Distribution coefficient and separation factor of n-butanol
Distribution
factor
n-butanol
DLi
DNa
DK
0.059
0.023
0.019
2.6
2.9
The effect of initial pH has been investigated over a range of 2 to 11 using molar solutions of
lithium, sodium, potassium chlorides and n-butanol at organic to aqueous phase 1:1. The data
obtained in this series of experiments are showed in Figure 3, which indicated that the pH has no
effect on the distribution coefficient of the lithium, sodium, potassium chlorides.
Figure 3 The influence of initial pH on LiCl, NaCl and KC1 extraction using n-butanol
The influence of organic to aqueous phase ratio on the separation factor has been studied within
the range of A / O = 1 / 5 to 3.2 / 1 using n-butanol and one normal solutions of lithium, sodium and
potassium chlorides. Figure 4 represents the results obtained in this series of experiments. A phase
ratio of about 1 has been found to be optimum for the separation factor, in good agreement with our
preliminary study. Subsequent tests used this ratio.
Figure 4 The influence of organic to aqueous phase ratio on the separation factor of LiCl, NaCl and
KCl using n-butanol.
1338
Progress in Materials and Processes
3.3. Precipitation of lithium carbonate
Precipitation of Li2CO3 was done at 65 - 70 °C because the solubility of lithium carbonate
decreases with increasing temperature. Test showed that precipitation with ammonium carbonate is
the most effective since ammonium chloride that also precipitates is eliminated by washing with hot
water. Lithium carbonate is precipitated from an aqueous lithium solution using ammonium
carbonate according to the following reaction (2):
The purity of the synthesised product is indicated in Table 3. From the results, the purity of the
recovered powder is 99.6 % (metal basis). The analysis shows that the major impurity is sodium
which may be attributed to the similar performance of physical and chemical properties of sodium and
lithium.
Table 3 Content of impurities in lithium carbonate
Li2CO3
Purity
(%)
99.6
Ca
＜0.01
Na
0.02
Content of major impurities (%)
K
Al
Si
Mg
0.01
＜0.01
＜0.01
＜0.01
Fe
＜0.01
4. Conclusion
The applicability of the n-butanol extraction technique for recovery of lithium chloride from
mixture containing lithium, sodium, potassium, and calcium chlorides has been demonstrated and the
process of carbonation and recovery of lithium carbonate from lithium chloride were also
investigated. Experiments showed that the n-butanol was the suitable solvent in terms of having good
distribution coefficients and separation factors. The purity of this lithium carbonate product was as
high as 99.6 %. Further studies remain to be done regarding the economics of this process prior to its
scale-up to industrial level.
Acknowledgements
The author thanks the Science Foundation of Jiangxi Provincial Office of Education (GJJ11702) and
Yichun University Project: Research on extraction of lithium carbonate from tantalum & niobium
tailings for financial support.
References
[1] Jandová, J.; Dvořák, P.; Vu, H.N. Hydrometallurgy 2010, 103, 12 - 18.
[2] Kunetsova, E.N.; Panchenkov, G.M.; and Kresova, N. A. Z. Fiz. Khim. 1966, 40, 688 - 691.
[3] Kondás, J.; Jandová, J. Acta. Metall. Slovaca. 2006, 12, 197 - 202.
[4] Morris, D. F. C.; Short, E. L. J. Inorg. Nucl. Chem. 1963, 25, 291 - 301.
[5] Lagos, S.; Becerra, R. J. Nucl. Mater. 2005, 347, 134 - 139.
[6] Veasey, T. J. Miner. Eng. 1997, 10, 1355 - 1362.
[7] Shin, S. M.; Kim, N. H.; Sohn, J. S.; Yang, D. H.; Kim, Y. H. Hydrometallurgy 2005, 79, 172 181.
[8] Somers, H.; Smith, J. R.; Dale, D. W.; Roman, R. M. J. Chem. Eng. 1971, 16, 74 - 75.
[9] Fernández, A. I.; Chimenos, J. M.; Segarra, M.; Fernández, M. A.; Espiell, F. Hydrometallurgy
1999, 53, 155 - 167.