Lithium isotope analysis

Lithium isotope analysis is a promising approach for characterising different deposits and may allow conclusions to be drawn about the nature of the deposits.

Application

Lithium isotope analysis is an extremely versatile method that is used to analyse processes, particularly in geochemistry and environmental sciences. A recent field of application is the characterisation of deposits, whereby lithium isotope analysis can provide insights into the formation, composition and origin of lithium resources. The method is also used in environmental and climate research and may also be used in medical and biological studies in the future.

Basics

Lithium is the lightest element with a solid aggregate state at room temperature and has two natural isotopes: 6Li (7.4 % relative abundance) and 7Li (92.6 % relative abundance). The large mass difference of over 10 % between the two isotopes leads to considerable fractionation in rocks and waters, which is attributed to various natural processes such as dissolution and precipitation reactions. This fractionation, given as δ7Li, can be up to 60 ‰ and makes it possible to draw conclusions about geological processes.

Lithium isotope analysis in combination with characteristic trace element patterns is a promising approach for characterising different deposits. The CEZA has already worked intensively on the development and application of such multi-parameter approaches in the past. This expertise was recently expanded to include lithium isotope analysis. An ion chromatography was established and verified that is capable of separating lithium from all interfering accompanying elements, in particular sodium, in spodumene samples within less than 3 hours. This is the fastest separation method for lithium to date.

Measurements using HR-MC-ICP-MS (High Resolution-Multi Collector – Inductively Coupled Plasma – Mass Spectrometry) showed a high reproducibility of the δ7Li values for both standards and spodumene samples in measurement solutions prepared by this separation. It was observed that spodumene samples can show significant differences in δ7Li of at least 8 ‰. This illustrates the potential of lithium isotope analysis for the characterisation of deposits.

Limitations

Despite its wide range of applications, lithium isotope analysis, like other isotope systems, also has some limitations. Complex sample matrices can affect the measurements, as can contamination and interference from other elements. The accuracy and reproducibility of the measurements require careful control and calibration.

Sample composition and quantity for analysis

Sample quality plays a crucial role in carrying out successful lithium isotope analyses. Samples must be carefully prepared to minimise contamination and enable accurate measurement of lithium. It is important to plan the sampling carefully in order to obtain representative results.

The amount of material required for a successful lithium isotope measurement depends on several factors, including the specific analytical technique, the sample preparation method and the concentration of lithium in the sample. Typically, only small amounts of material are required, on average a few hundred milligrams. However, the amount depends on the specific requirements of the analysis. The exact amount of material required is best determined in consultation with our experienced analysts, taking into account the specific requirements of the planned analysis.