Partial matrix matching multi-energy calibration for direct quantification of Al, Fe, Li and Si in spodumene by laser-induced breakdown spectroscopy

Abstract

The increasing demand for new energy sources, such as lithium batteries, has driven exploration of lithium sources like brines and pegmatites, with spodumene being the only mineral with an economically viable extraction route. In 2020, the European Commission listed lithium as a critical raw material. To ensure the quality of spodumene, rapid and accurate analytical methods are essential. Laser-induced breakdown spectroscopy (LIBS) is a promising technique for direct, rapid multi-element analysis, but it usually suffers from intense matrix effects. This study proposes a partial matrix matching multi-energy calibration approach (PMM-MEC) for the determination of Al, Fe, Li and Si in spodumene samples from different locations in Minas Gerais, Brazil, using LIBS. A mixture of spodumene samples, previously characterized by XRF and ICP OES, was used as the standard. The PMM-MEC method was validated by determining Al, Fe, and Ti in bauxite (CRM BXMG-2); Ca, Si and Mn in manganese ore (CRM NCS47009); and Al, Ca and Si in portland cement (CRM 1889a). Sodium and boron, or lithium and boron, were used as internal standards to mitigate matrix effects and improve the method's accuracy. The method provided relative errors between −12% and 10% and relative standard deviations (RSD) ranging from 0.2% to 2.5%. The limits of detection for all analytes were in the 0.0003–0.7% range.