Micro-flow magnetic separation of rare earth metals ions in aqueous solutions

Due to application in many modern technologies, rare earth elements (REE) nowadays attract higher and higher interest. These metals are produced both from primary and secondary sources in hydrometallurgical processes which are often complicated and costly. The most problematic step of production is the separation of ions. Due to these reasons it is desirable to improve the current processes.
Here, High Magnetic Gradient Separation (HGMS) appears to be attractive. It utilizes the different magnetic properties of rare earth metal ions to achieve separation by attraction or repulsion in an inhomogeneous magnetic field [1][2].
The present work investigates the separation of REE ions in aqueous solutions based on their magnetic properties. The experiments were carried out in micro-flow cells produced by a 3D printing technology (Fig. 1). The cells consist of a spiral channel next to which a spiral of an iron wire is arranged. The inhomogeneous magnetic field in the cross section of channel is created by the placement of the cell in a laboratory electromagnet. During the flow of the solution the metal ions experience a force from the gradient magnetic field. At the outflow, the near-wire and the far-wire half of the solution are collected and analyzed. Different solutions consisting of a single species and of mixtures of metals ions were investigated at different flow rates, and the concentrations were analyzed by UV/VIS spectrometry.
The results will be presented in detail at the conference. The conducted experiments state a preliminary determination of the influence of a gradient magnetic field on the transport of ions in aqueous solutions in the flow state.

[1] K. Kołczyk, M. Wojnicki, D. Kutyła, R. Kowalik, P. Żabiński, A. Cristofolini, Archives of Metallurgy and Materials, 61 (2016) 1919–1924.
[2] K. Kolczyk, D. Kutyla, M. Wojnicki, A. Cristofolini, R. Kowalik, P. Zabinski, MAGNETOHYDRODYNAMICS 52 (2016) 541-547.