Precious element analysis in lead and zinc processing with Thermo Scientific ARL PERFORM’X Series Advanced X-ray Fluorescence Spectrometers

Importance of the Topic

The determination of trace precious metals (silver and gold) in lead and zinc ores is critical for optimizing recovery and profitability in mining. X-ray fluorescence (XRF) offers rapid, non-destructive analysis suitable for both pyrometallurgical and hydrometallurgical processes.

Objectives and Study Overview

This application note evaluates the performance of the Thermo Scientific ARL PERFORM’X 2500 W XRF spectrometer for quantifying trace levels of Ag and Au in lead and zinc ore concentrates. Synthetic calibration standards and repeatability tests were conducted to assess sensitivity, accuracy, and precision.

Methodology and Instrumentation

• Sample Preparation: Fine ore powders pressed into pellets without binders.
• Calibration: Synthetic standards for Ag (Kα) and Au (Lα, Lβ) across relevant concentration ranges.
• Analytical Conditions:
  • Ag Kα: LiF200 crystal, 60 kV, 40 mA, 60 s counting.
  • Au Lα/Lβ: LiF200, 50 kV, 50 mA, 200 s counting.
  • Additional elements (Cu, Fe, Pb, Zn, As, Cd) measured under optimized conditions.

Instrumentation Used

The ARL PERFORM’X 2500 W spectrometer features:

• 5GN+ Rh X-ray tube with 50 μm Be window and low-current filament for long-term stability.
• Six primary beam filters, four collimators, up to nine analyzing crystals, two detectors, helium purge.
• LoadSafe sample handling and Secutainer vacuum collection for pellet protection.
• Liquid cassette recognition and helium shutter for spectral chamber safety.

Main Results and Discussion

• Calibration Correlation: R² > 0.9989 for Ag and > 0.9997 for Au lines, demonstrating linear response.
• Limits of Detection: below 0.1 ppm for Au; Ag detection limit not determined (ND) under tested conditions.
• Repeatability: Ten consecutive runs on a synthetic sample yielded relative standard deviations below 3% for Ag and <12% for Au Lβ, confirming high precision.

Benefits and Practical Applications

The ARL PERFORM’X enables:

• High-throughput, non-destructive analysis of precious metals in complex ore matrices.
• Enhanced profitability through accurate trace metal quantification, supporting process optimization.
• Reliable quality control in mining operations, minimizing analytical downtime.

Future Trends and Opportunities

• Integration of automated sample handling and in-line XRF stations for real-time process monitoring.
• Expansion of ultralight element analysis via improved tube windows and purge systems.
• Data-driven approaches combining XRF with machine learning for predictive ore grade modeling.

Conclusion

The Thermo Scientific ARL PERFORM’X 2500 W XRF spectrometer demonstrates exceptional sensitivity, accuracy, and precision for trace silver and gold analysis in lead and zinc ores. Its robust design and advanced safety features make it a versatile tool for mining laboratories and process control applications.