Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) can be used for bulk analysis and mapping of critical elements throughout the supply value chain, from raw materials (including recyclable materials) to highly refined products like next-generation battery components. This study aims to provide new methodologies to quantify EU-listed critical raw materials in metallurgical slags and mine tailings. These sources, often by-products of mining exploration or metallurgical production, are typically discarded as waste, despite containing valuable resources [1]. For this reason, determining the quantities and concentrations of these elements is crucial for evaluating the economic viability of their potential recovery from what we define as secondary resources.

Elemental content is usually determined using techniques such as atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES), and ICP-MS. These methods involve converting solid samples into liquid solutions through digestion, combustion, or fusion. However, this sample dissolution step has drawbacks, including long preparation times and risks of contamination or analyte loss. Refractory minerals like zircon, garnet, or alumina can resist digestion, reducing recovery rates for trace elements. Direct analysis of solid samples can overcome these issues and improve sensitivity by avoiding sample dilution.

We compare here ICP-MS/MS analysis on liquid samples obtained after microwave-assisted acid dissolution with LA-ICP-MS analysis for determining Mn ores and slags enriched in rare earth elements (REEs). For LA-ICP-MS, we will present two approaches, particularly useful in cases where dissolution proves to be challenging: (i) analysis of glass beads obtained through borax flux preparation of raw powders, and (ii) direct analysis on pelletized powders using a novel non-matrix matched calibration strategy [2]. The latest method proved to be a suitable candidate for direct determination of solid samples without the use of specific SRM, often not available for the different matrices analyzed.

[1] Gaustad, G., Williams, E., Leader, A. Resources, Conservation and Recycling, 2021,167, 105213

[2] Mervič, K., Šelih, V.S., Šala, M., van Elteren, J.T. Talanta, 2024,1, 271:125712.