Quality Control of Li₂CO₃ from Salars by XRD analysis using ARL X’TRA Companion benchtop XRD

Significance of the Topic

Lithium carbonate produced from salars is a key precursor for lithium-ion batteries, ceramics and glass. High purity and well-defined crystallinity directly influence performance, processing efficiency and cost in these industries.

Objectives and Study Overview

This application note demonstrates how bench-top X-ray diffraction can be applied to assess the quality and phase composition of lithium carbonate samples from salars. Two samples were compared to evaluate contaminant levels, phase purity and total lithium content.

Methodology and Instrumentation

• Sample preparation: Powdered Li₂CO₃ measured in reflection geometry.
• Measurement conditions: 10-minute scans per sample using Cu Kα radiation with Ni filter.
• Phase quantification: Rietveld refinement via Profex1 (BGMN algorithm) employing a fundamental parameters approach.

Instrumentation

• Thermo Scientific ARL X’TRA Companion bench-top XRD system with θ/θ goniometer in Bragg-Brentano geometry.
• 600 W X-ray source (Cu or Co), divergence and Soller slits for radial and axial collimation, variable beam knife to reduce air scattering.
• Solid-state pixel detector (55×55 µm pitch) enabling rapid data collection.
• One-click Rietveld quantification and automated LIMS data transmission.
• Optional integrated water chiller for temperature stability.

Main Results and Discussion

• Sample A composition: 95.3 wt% Li₂CO₃; contaminants include 3.3 wt% NaCl, 0.7 wt% Na₂Mg(CO₃)₂ and 0.7 wt% Li₂(SO₄)·H₂O. Total Li content determined by refinement is 18.0 wt% (reference 17.2 wt%).
• Sample B composition: 99.5 wt% Li₂CO₃; minor phases of 0.2 wt% Na₂Mg(CO₃)₂, 0.2 wt% Li₂(SO₄)·H₂O and 0.1 wt% NaCl. Total Li content is 18.7 wt% (reference 18.5 wt%).
• Both samples exhibit full crystallinity, and Rietveld fits match chemical analysis closely, confirming the reliability of the method.

Benefits and Practical Applications

• Rapid 10-minute measurement accelerates quality control cycles.
• Non-destructive phase identification and quantification of lithium content.
• Automated, reproducible one-click Rietveld analysis simplifies operation.
• Seamless LIMS integration supports efficient data management in production environments.

Future Trends and Opportunities

• Extension to in situ XRD monitoring during lithium extraction and evaporation processes.
• Adoption of next-generation detectors for increased sensitivity and resolution.
• Application of similar workflows to other battery materials and advanced ceramics.
• Integration of AI-driven phase recognition for real-time process optimization.

Conclusion

Bench-top XRD using the ARL X’TRA Companion provides a fast, robust and accurate approach to assess lithium carbonate purity and crystallinity. Its automated Rietveld refinement and LIMS integration make it an ideal tool for industrial process control and quality assurance.

Reference

1. N. Döbelin, R. Kleeberg, J. Appl. Crystallogr. 2015, 48, 1573-1580.