Modeling Preparative Chromatographic Separation of Heavy Rare Earth Elements and Optimization of Thulium Purification

Mark Max-Hansen, Hans-Kristian Knutson, Christian Jönsson, Marcus Degerman, Bernt Nilsson^*

Department of Chemical Engineering, Lund University, Lund, Sweden.

DOI: 10.4236/ampc.2015.55016                

Abstract

Rare Earth Elements are in growing demand globally. This paper presents a case study of applied mathematical modeling and multi objective optimization to optimize the separation of heavy Rare Earth Elements, Terbium-Lutetium, by means of preparative solid phase extraction chromatography, which means that an extraction ligand, HDEHP, is immobilized on a C18 silica phase, and nitric acid is used as an eluent. An ICP-MS was used for online detection of the Rare Earths. A methodology for calibration and optimization is presented, and applied to an industrially relevant mixture. Results show that Thulium is produced at 99% purity, with a productivity of 0.2 - 0.5 kg Tm per m³ stationary phase and second, with Yields from 74% to 99%.

Keywords

Rare Earth Elements, Chromatography, Model Calibration, Optimization, Multi-Objective, HDEHP

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Verma, S.P. and Santoyo, E. (2007) High-Performance Liquid and Ion Chromatography: Separation and Quantification Analytical Techniques for Rare Earth Elements. Geostandards and Geoanalytical Research, 31, 161-184.
[2]	Pierce, T.B. and Hobbs, R.S. (1963) The Separation of the Rare Earths by Partition Chromatography with Reversed Phases: Part 1. Behavior of Column Material. J Chrom A, 12, 74-80.
[3]	Russell, R.G. and Pearce, D.W. (1943) Fractionation of the Rare Earths by Zeolite Action. Journal of the American Chemical Society, 65, 595-600. http://dx.doi.org/10.1021/ja01244a029
[4]	Lister, B.A. and Smith, M.L. (1948) The Fractionation of Cerium (III) and Neodymium Mixtures on an Ion-Exchange Column. Journal of the Chemical Society, 1272-1275. http://dx.doi.org/10.1039/jr9480001272
[5]	Choppin, G.R. and Silva, R.J. (1956) Separation of the Lanthanides by Ion Exchange with Alpha-Hydroxy Isobutyric Acid. Journal of Inorganic and Nuclear Chemistry, 3, 153-154. http://dx.doi.org/10.1016/0022-1902(56)80076-6
[6]	Harris, D.H. and Tompkins, E.R. (1947) Ion-Exchange as a Separation Method; Separations of Several Rare Earths of the Cerium Group (La, Ce, Pr and Nd). Journal of the American Chemical Society, 69, 2792-2800. http://dx.doi.org/10.1021/ja01203a061
[7]	Kettele, B.H. and Boyd, G.E. (1947) The Exchange Adsorption of Ions from Aqueous Solutions by Organic Zeolites. IV. The Separation of the Yttrium Group Rare Earths. Journal of the American Chemical Society, 69, 2800-2812.
[8]	Spedding, F.H., Powell, J.E. and Wheelwright, E.J. (1956) The Stability of the Rare Earth Complexes with N-Hydroxyethyl Ethylenedia-minetriacetic Acid. Journal of the American Chemical Society, 78, 34-37.
[9]	Minczewski, J. and Dybczynski, R. (1961) Separation of Rare Earths on Anionexchange Resins. III. The Position of Scandium in the Separation Scheme of Rare Earth Complexes with Ethylenediaminetetraacetic Acid. Journal of Chromatography A, 7, 79-96.
[10]	Meyer, L. and Bras, B. (2011) Rare Earth Metal Recycling. 2011 IEEE International Symposium on Sustainable Systems and Technology (ISSST), Chicago, 16-18 May 2011, 1-6.
[11]	Jordens, A., Cheng, Y.P. and Waters, K.E. (2013) A Review of the Benefication of Rare Earth Element Bearing Minerals. Minerals Engineering, 41, 97-114.
[12]	Ojala, F., et al. (2012) Modelling and Optimisation of Preparative Chromatographic Purification of Europium. Journal of Chromatography A, 1220, 21-25. http://dx.doi.org/10.1016/j.chroma.2011.11.028
[13]	Max-Hansen, M., et al. (2011) Optimization of Preparative Chromatographic Separation of Multiple Rare Earth Elements. Journal of Chromatography A, 1218, 9155-9161. http://dx.doi.org/10.1016/j.chroma.2011.10.062
[14]	Knutson, H. (2014) Experimental Productivity Rate Optimization of Rare Earth Element Separation through Preparative Solid Phase Extraction Chromatography. Journal of Chromatography A, 1348, 47-51. http://dx.doi.org/10.1016/j.chroma.2014.04.085
[15]	Karlsson, D. (2004) Aspects of the Design of Preparative Chromatography for Purification of Antibodies. Ph.D. Thesis, Lund University, Lund.
[16]	Jakobsson, N., et al. (2005) Optimisation and Robustness Analysis of a Hydrophobic Interaction Chromatography Step. Journal of Chromatography A, 1099, 157-166. http://dx.doi.org/10.1016/j.chroma.2005.09.009
[17]	Guichon, G., Felinger, A., Shirazi, D.G. and Katti, A.M. (2006) Fundamentals of Preparative and Nonlinear Chromatography. 2nd Edition, Elsevier Inc., San Diego.
[18]	Price, K., Storn, R. and Lampinen, J. (2005) Differential Evolution: A Practical Approach to Global Optimization. Springer, Berlin.
[19]	Wang, Y.-N., et al. (2010) Multi-Objective Self-Adaptive Differential Evolution with Elitist Archive and Crowding Entropy-Based Diversity Measure. Soft Computing, 14, 193-209. http://dx.doi.org/10.1007/s00500-008-0394-9
[20]	Holmqvist, A., et al. (2013) A Model-Based Methodology for the Analysis and Design of Atomic Layer Deposition Processes—Part III: Constrained Multi-Objective Optimization. Chemical Engineering Science, 96, 71-86. http://dx.doi.org/10.1016/j.ces.2013.03.061
[21]	Borg, N. (2013) Modeling and Calibration of Preparative Chromatography. Ph.D. Thesis, Lund University, Lund.