Microwave Digestion and ICP-MS Determination of Major and Trace Elements in Waste Sm-Co Magnets

Abstract

In this article, inductively coupled plasma mass-spectrometry (ICP-MS) and inductively coupled plasma optical-emission spectrometry (ICP-OES) were used for the development of an analytical procedure for analysis of the waste of Sm-Co magnets. Experimental parameters related to microwave digestion processes and acid concentrations were optimized. Microwave digestion was carried out in mixtures of HF, HCl, HNO3 and H2SO4. The complete dissolution of the samples occurred in the system: 10 mL H2O, 2 mL HNO3, 10 mL HCl and 1 mL H2SO4. The dependence of the matrix effect on the ICP-MS analysis of waste Sm-Co magnets was studied and optimal instrumental parameters were investigated (nebulizer gas flow, sampling depth and potential at the extractor lens). The optimal conditions were a nebulizer gas flow of 0.85–0.90 L/min, a sampling depth of 101, potential at the extractor lens of −400 V and a sample flow rate of 50 rpm. A recovery test and inter-method experiments were performed to verify the accuracy of the proposed method.

Green and Sustainable Rare Earth Element Recycling and Reuse from End-of-Life Permanent Magnets

“…A one-stage microwave oven digestion procedure to recover waste Sm-Co magnet samples was carried out in a mixture of HCl/HNO 3 /HF/H 2 SO 4 [102]. Experimental parameters related to the microwave decomposition processes (acid concentration, time, and temperature) were optimized for achieving the quantitative recovery of elements (>95%).…”

X-ray Fluorescence Analysis of Waste Sm-Co Magnets: A Rational Approach

“…Samarium and cobalt-based magnets are typically analyzed using such methods as inductively coupled plasma optical emission spectrometry (ICP-OES) [23][24][25][26], inductively coupled plasma mass spectrometry (ICP-MS) [27][28][29] and microwave plasma atomic emission spectrometry (MP-AES) [19]. However, the key drawback of ICP-OES and ICP-MS is the necessity of sample dissolution.…”

“…However, the key drawback of ICP-OES and ICP-MS is the necessity of sample dissolution. This often requires time-consuming and rather laborious sample preparation, for example, using microwave decomposition [27]. In addition, ICP-MS is effective mainly for the determination of impurity elements (n × 10 −6 to n × 10 −3 wt%), while ICP-OES is capable of determining the major elements (above n × 10 −1 wt%); however, sample preparation requires significant dilution, which might introduce additional uncertainties.…”