Elemental Analysis of Brine Samples used for Lithium Extraction

Significance of the topic

Lithium is a key element for high-density rechargeable batteries used in electronics, electric vehicles, and large-scale energy storage. Rapid growth in demand for battery-grade lithium drives the need for reliable, high-throughput analytical methods to monitor lithium brine compositions and control extraction processes.

Aims and overview of the study

This work evaluates the performance of the Agilent 5800 Vertical Dual View (VDV) ICP-OES coupled with the AVS 7 switching valve for fast, robust elemental analysis of high matrix brine samples. The goal is to demonstrate accurate multi-element quantification (B, Ca, Cl, K, Li, Mg, Mn, Na, S, Si, Sr) in real seawater and underground brines containing 15–25% NaCl.

Methodology and instrumentation

Samples were diluted in 5% HNO3 and analyzed using the Agilent 5800 VDV ICP-OES equipped with:

• SeaSpray glass concentric nebulizer and cyclonic spray chamber
• 1.8 mm injector demountable torch
• AVS 7 seven-port high-speed switching valve for in-line premixing of internal standards
• Vista Chip III solid-state detector covering 167–785 nm
• Agilent SPS 4 autosampler

An internal standard mixture of Sc, In and Rb was introduced via the AVS 7 to correct matrix and non-spectral interferences. Calibration employed multi-element and single-element standard solutions in 5% HNO3, with MultiCal used to extend linear dynamic ranges for Na, Mg, and Ca.

Main results and discussion

Detection limits determined in 1% NaCl spiked at 20 ppb ranged from 0.0006 mg/L (Mn) to 0.13 mg/L (K). Seven brine samples diluted 1:20 or 1:100 yielded accurate concentrations for all elements, with relative recoveries within 10% for spiked tests. Long-term stability was demonstrated by measuring 120 replicate samples over 2.5 hours (73 s/sample), showing RSDs below 1.5% for major elements and under 6% for trace Si.

Benefits and practical applications

This approach offers:

• Fast sample-to-sample time (73 s) with minimal carry-over
• Robust handling of high TDS matrices and viscous brines
• Wide linear dynamic range allowing simultaneous major and trace element analysis without multiple dilutions
• Reduced maintenance due to lower sample introduction system exposure

Laboratories and industrial operations can implement this method to support quality control, process monitoring, and research in lithium extraction.

Future trends and possibilities

Advances may include integration of real-time data feedback and predictive maintenance guided by machine learning, further reducing downtime. Expansion of spectral screening tools and automation of calibration routines will enhance throughput. Coupling ICP-OES with online sampling from extraction sites could enable continuous process control and optimization in lithium recovery.

Conclusion

The Agilent 5800 VDV ICP-OES with AVS 7 offers a powerful, efficient solution for elemental profiling of high-salt brine samples. Combining robust plasma stability, in-line internal standard mixing, and broad wavelength coverage, the method achieves accurate, precise multi-element determinations with minimal sample preparation and maintenance.

References

1. Xu C. et al. Commun Mater 1, 99 (2020).
2. Agilent publication 5991-6863EN.
3. Agilent publication 5994-1516EN.
4. Agilent publication 5994-1518EN.
5. Agilent publication 5994-2164EN.
6. Agilent publication 5994-4868EN.