| 1. |
- Andersson, Niklas, et al.
(författare)
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Model-Based Comparison of Batch and Continuous Preparative Chromatography in the Separation of Rare Earth Elements
- 2014
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 53:42, s. 16485-16493
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Tidskriftsartikel (refereegranskat)abstract
- The demand for rare earth elements (REEs) is growing, while the future supply is uncertain. Their unique electronic characteristics make them irreplaceable, and the commercial value of pure fractions is high. A model-based simulation study is presented that compares batch chromatography with the twin-column MCSGP (multicolumn countercurrent solvent gradient purification) process for ion-exchange chromatography of the four-component system neodymium, samarium, europium, and gadolinium. The last three components are considered products with individual purity requirements of 99%. The twin-column process has been shown to be a good alternative to the batch process regarding modifier consumption and productivity since it enables internal recycling to achieve high purities. A new cut strategy for MCSGP is applied where subfractions are taken from each outlet. Two multiobjective optimizations with yield, solvent productivity, and productivity objectives show that the MCSGP process is a better alternative than batch chromatography.
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| 2. |
- Knutson, Hans-Kristian, et al.
(författare)
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Experimental productivity rate optimization of rare earth element separation through preparative solid phase extraction chromatography.
- 2014
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673. ; 1348, s. 47-51
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Tidskriftsartikel (refereegranskat)abstract
- Separating individual rare earth elements from a complex mixture with several elements is difficult and this is emphasized for the middle elements: Samarium, Europium and Gadolinium. In this study we have accomplished an overloaded one-step separation of these rare earth elements through preparative ion-exchange high-performance liquid chromatography with an bis (2-ethylhexyl) phosphoric acid impregnated column and nitric acid as eluent. An inductively coupled plasma mass spectrometry unit was used for post column element detection. The main focus was to optimize the productivity rate, subject to a yield requirement of 80% and a purity requirement of 99% for each element, by varying the flow rate and batch load size. The optimal productivity rate in this study was 1.32kgSamarium/(hmcolumn(3)), 0.38kgEuropium/(hmcolumn(3)) and 0.81kgGadolinium/(hmcolumn(3)).
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| 3. |
- Max-Hansen, Mark
(författare)
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Modeling and Optimization of Rare Earth Element Chromatography
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Rare Earth Elements are a group of metals, that are of growing technical and economical importance. Current separation techniques can be detrimental to the environment, and a clean technology for separation has been devised, based on analytical chromatography of the REEs. The thesis presents column preparation and impregnation to give desired properties of the separation system, experimental and model based optimization for operating points and design of a chromatography step for separating REEs.
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