EDXRF Analysis of Nickel Ore as Pressed Powders in an Air Environment

Significance of the Topic

The growing demand for nickel, driven by its essential role in lithium-ion battery production for electric vehicles, places significant importance on rapid, accurate and precise quantification of nickel ore in both mining and refining operations. Energy-dispersive X-ray fluorescence (EDXRF) offers a non-destructive, minimal-preparation approach well suited for on-site and remote analysis.

Aims and Study Overview

This application note evaluates the performance of the Thermo Scientific ARL QUANT’X EDXRF spectrometer for the determination of major and trace elements in lateritic and sulfidic nickel ore samples prepared as pressed powders. Key objectives include establishing calibration protocols, assessing accuracy and repeatability, and demonstrating the method’s suitability for routine process and quality control.

Methodology and Sample Preparation

Seventeen OREAS® certified reference materials covering a wide concentration range for oxides and elements (MgO, Al₂O₃, SiO₂, SO₃, K₂O, CaO, TiO₂, Cr₂O₃, MnO, Fe₂O₃, Co, Ni, Cu, Zn) were used for calibration. Powdered samples were pressed into pellets at 20 tonnes without binder. Spectra were collected in air over a total live time of 300 s, using three excitation conditions with variable tube voltage (4–16 kV), filters and live times to optimize sensitivity for low-, mid- and high-Z elements.

Used Instrumentation

• ARL QUANT’X EDXRF spectrometer equipped with a Silicon Drift Detector (30 mm² active area)
• 50 W Rh/Ag air-cooled X-ray tube, voltage up to 50 kV
• Nine primary beam filters and three automated excitation settings
• 10-position autosampler with spinner for unattended analysis

Main Results and Discussion

Calibration curves demonstrated excellent linearity (R² ≥ 0.9839) and low root mean square error (RMSE ≤ 0.8 wt% for major oxides and ≤ 0.02 wt% for trace elements). Validation on two independent CRMs (192 and 199) yielded recovery within ±5% of certified values for all components. Repeatability studies (10 replicates per CRM) showed relative standard deviations below 1% for most analytes; higher RSDs (up to ~7%) were observed only for very low concentration species such as TiO₂ in certain matrices.

Benefits and Practical Applications

• Fast, multi-element analysis without vacuum or protective atmospheres
• Minimal sample preparation and ability to analyze pressed powders directly
• High throughput via autosampler for remote or continuous monitoring
• Suitable for process control, grade assessment and metallurgical accounting in mining operations

Future Trends and Applications

Advancements in detector technology, portable and handheld EDXRF instruments, and integration with digital data management and artificial intelligence are expected to further enhance field deployability, analytical speed and data interpretation. Development of on-line and at-line measurement systems will support real-time monitoring of ore quality, improving resource efficiency and reducing operational costs.

Conclusion

The ARL QUANT’X EDXRF spectrometer offers a robust, rapid and reliable solution for multi-element analysis of nickel ores as pressed powders in air. The method delivers high accuracy, precision and throughput, making it an ideal tool for quality control in mining and refining environments.