Analysis of Lithium Ores Using Handheld Direct Diffuse Reflectance FTIR Spectroscopy

Significance of the Topic

Demand for lithium has surged due to its central role in rechargeable batteries for electric vehicles and stationary energy storage.
Rapid, non-destructive field analysis of lithium ore is essential to accelerate exploration and secure supply chains.
Traditional DRIFTS methods require time-consuming sample preparation and liquid nitrogen cooling, limiting on-site use.

Objectives and Study Overview

This work assesses a direct diffuse reflectance FTIR approach using the Agilent 4300 handheld FTIR spectrometer to identify and quantify lithium ores on site.
The goals include comparing direct-DRIFTS to legacy DRIFTS and ATR techniques, expanding spectral libraries, and creating multivariate models for mineral recognition and concentration estimation.

Methodology and Instrumentation

The Agilent 4300 handheld FTIR was fitted with a diffuse reflectance sampling interface for direct-DRIFTS measurements.
Data were collected over the mid-IR range with 128 scans at 4 cm–1 resolution in under one minute per sample.
MicroLab Mobile software handled data acquisition and library searches against 165 industrial ore spectra and 971 geology reference spectra.
MicroLab Expert on PC was used to develop quantitative multivariate models based on partial least squares analysis.

Main Results and Discussion

Direct-DRIFTS spectra exhibited richer features than ATR, with stronger peaks extending into the near-IR region and more distinct hydroxyl and Reststrahlen bands.
Major lithium ores including spodumene, petalite, amblygonite, lepidolite and zinnwaldite were successfully distinguished by their unique spectral signatures.
Accessory minerals in pegmatite, such as biotite, garnet, tourmaline and apatite, were also identified directly on rock surfaces without sample grinding.
Library matching enabled confident identification of plagioclase feldspar and indicator minerals, aiding exploration decisions.
Quantitative models were developed to predict drill core depth and percent calcite as an exploration vector, as well as spodumene and petalite content, showing high correlation with reference methods.

Practical Benefits and Applications

The handheld direct-DRIFTS method requires no sample prep or destruction, enabling rapid on-site mineral screening.
Real-time identification supports exploration targeting, reduces lab transport and analysis delays, and improves decision making in the field.
Quality assessment of concentrated lithium ores such as SC6 spodumene can be performed before shipping or processing.

Future Trends and Potential Applications

Expansion of in situ direct-DRIFTS to other critical minerals and geological settings is anticipated.
Integration with automated field workflows, machine learning for spectral interpretation, and cloud-based data sharing will enhance efficiency.
Development of broader quantitative models for additional ore types and contaminants will further support exploration and process control.

Conclusion

The Agilent 4300 handheld FTIR with direct-DRIFTS interface offers a fast, accurate and non-destructive solution for lithium ore analysis in the field.
Detailed spectral features, combined with robust multivariate modeling, enable both qualitative identification and quantitative assessment of lithium minerals.
This approach promises to accelerate exploration, improve resource evaluation and streamline lithium supply chains.

Used Instrumentation

• Agilent 4300 handheld FTIR spectrometer
• Diffuse reflectance sampling interface
• Internal ATR interfaces (diamond and germanium) for comparison studies
• MicroLab Mobile and MicroLab Expert software packages

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