Insights about inductively coupled plasma optical emission spectroscopy interferences of major rare earth elements in complex e-waste feeds

• Published in: Spectrochimica acta. Part B: Atomic spectroscopy Vol. 191; p. 106399
• Main Authors: Patil, Ajay B., Tarik, Mohamed, Schuler, Albert J., Torrent, Laura, Struis, Rudolf P.W.J., Ludwig, Christian
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.05.2022; Elsevier BV
• Subjects: Algorithms; Analytical methods; Chemical composition; Coordination compounds; E-waste; Electronic waste; Emission spectroscopy; Fluorescence; Inductively coupled plasma mass spectrometry; Inductively coupled plasma optical emission spectroscopy; Interference; Mass spectrometry; Mass spectroscopy; Metal concentrations; Metals; Method development; Optical emission spectroscopy; Optoelectronics; Permanent magnets; Rare earth elements; Rare earths; Raw materials; Recycling; Spectral interferences; Trace elements; E-waste; Inductively coupled plasma optical emission spectroscopy; Spectral interferences; Method development; Rare earths
• ISSN: 0584-8547; 1873-3565
• DOI: 10.1016/j.sab.2022.106399

The advent of rare earth elements (REEs) with optoelectronic properties has shifted the technology paradigm from digital to a smart and hybrid world. Their substantial uses also resulted in a large piling up of e-waste. Therefore, e-waste is now a lucrative recycling target for the recovery of such critical raw materials. Their recycling from e-waste is often challenged by dilute metal concentration, complex composition, and difficult chemical characterisation. Generally, the characterisation of e-waste involves elemental determination techniques, such as inductively coupled plasma optical emission spectroscopy (ICP-OES) or inductively coupled plasma mass spectrometry (ICP-MS). ICP-OES is attractive for a recycling or research sector because it has a higher matrix tolerance and lower cost than ICP-MS. In this work, the intensity at 445 line positions measured by an ICP-OES instrument was compiled in a 2D diagram to map interferences by 27 prominent lines from 9 REEs. The second diagram shows the impact at 230 neighbouring line positions measured in each of, in total, 17 (i.e., 9 REEs and 8 non-REEs) single-standard solutions in terms of the concentration of the element type affected. The spectral interference correction algorithm proposed here had been developed by us for a recycling process to obtain pure Y, Eu, and Tb from fluorescent powder (FP) in spent lamps. The ICP-OES analysis and spectral interference correction approach presented here can be applied to any element and e-waste type. To underline this, the paper gives examples for elements in dissolved FP and surrogate NdFeB magnet samples. [Display omitted] •Quantification approach for interference effect of REEs in complex matrices.•Identification of the interferences of REE and non-REE elements in ICP-OES analysis.•Interference correction and REE quantification in e-waste.•Possibility of post processing correction using the developed method.