Characterization of spodumene concentrates – Implications for traceability

Lithium-ion batteries are an important high-tech technology for the electrification of the transport sector and the transition to renewable energies. Depending on the battery type, elements such as cobalt, nickel, manganese or phosphate are required in different amounts, but lithium is not interchangeable in all of them. The raw materials for the lithium in these batteries are derived from brines as well as from mineral resources such as spodumene pegmatites, which occur almost worldwide and are mainly mined commercially in Australia, Canada and Brazil. The spodumene mineral concentrates produced there are traded globally, as the chemical processing into lithium carbonate or lithium monohydroxide does not often take place in the country of mining.

In this study, spodumene concentrates of different origin were used to investigate which methods are suitable to distinguish between the various deposits. The spodumene samples were analysed by optical microscopy and EDS measurements to characterise microstructure, inclusions and intergrowths. For trace element contents solution ICP-MS and for lithium isotope ratio MC-ICP-MS analyses were carried out.

The intergrowth differs mainly with regard to the presence or absence of locally very complex spodumene-quartz associations. Geochemical results show differences between the concentrates especially for trace elements such as Nb, Fe, or Ga. The lithium isotope ratio (δ⁷Li) varies from -1 to about 11 ‰. The results show that it is possible to differentiate between spodumene concentrates based on geochemical, mineralogical, and isotopic parameters. Thus, our data contribute to lithium fingerprinting as a proof of origin in mineral value chains.