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

has been cited by the following article:

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

  AUTHORS: Mark Max-Hansen, Hans-Kristian Knutson, Christian Jönsson, Marcus Degerman, Bernt Nilsson

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

  JOURNAL NAME: Advances in Materials Physics and Chemistry, Vol.5 No.5, April 29, 2015

  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%.