A statistical study for the evaluation of the performance of conventional and advanced digestion methods for monazite ores

Abstract

Inductively coupled plasma mass spectrometry (ICP-MS) remains one of the most reliable techniques for the determination of rare earth element (REE) concentrations in geological samples. One of the greatest challenges in ICP-MS is identifying sample dissolution methods that are both effective and accessible in remote mining sites. This study aims to compare several open vessel acid digestion methods with well-established methods, microwave-assisted digestion and alkali fusion, to determine which methods are most accurate for the analysis of light REEs in monazite samples. The four-acid digestion method of HF/HNO₃/HCl/HClO₄ was found to give comparable results to alkali fusion for the light REEs (LREEs), which predominate monazite samples. Statistical analysis of the investigated methods proves the comparability of the recoveries of LREEs obtained by the four-acid digestion method, which can be performed either in laboratories or by on-site preparation, with other methods that require costly techniques and well-equipped laboratories.