Analysis of nickel ore with the ARL OPTIM’X WDXRF Spectrometer

Importance of the Topic

Nickel is a critical metal used extensively in lithium-ion batteries and stainless steel production. Rapid and precise quantification of nickel ore composition is essential for efficient mining, process control, and refining operations. X-ray fluorescence (XRF) techniques offer minimal sample preparation and high throughput, making them valuable for quality assurance in both lateritic and sulfide nickel ore processing.

Aim and Overview of the Study

This application note evaluates the performance of the Thermo Scientific ARL OPTIM’X WDXRF Spectrometer for analyzing nickel ore materials. Calibration, method validation, and repeatability tests were conducted to demonstrate accuracy, precision, and analysis speed under routine laboratory conditions.

Methodology

Samples of lateritic and sulfidic nickel ores were fused into glass beads using a 1:20 sample-to-flux ratio with ammonium nitrate as an oxidizer. Calibration employed 18 certified reference materials (CRMs) covering oxide concentration ranges for Al2O3, CaO, Cr2O3, Fe2O3, K2O, MgO, MnO, NiO, SiO2, TiO2, Co3O4, P2O5, SO3, and ZnO. Characteristic X-ray intensities were related to oxide concentrations, yielding calibration curves with coefficients of determination (R2) above 0.95 and low standard errors of estimate (SEE).

Instrumentation

• ARL OPTIM’X WDXRF Spectrometer with SmartGonio goniometer covering F to U.
• Measurement conditions: 50 W power, 30 kV, ~1.7 mA; total analysis time 10.4 min (elements measured in gonio mode).
• Optionally 200 W version reduces counting times by a factor of 2.5, lowering total analysis time to ~4 min.

Key Findings and Discussion

• Calibration quality: R2 ≥ 0.983 and SEE values below 0.25 % for major oxides, indicating excellent linearity and sensitivity.
• Repeatability: Ten replicate analyses of three CRMs (samples 181, 184, 198) showed relative standard deviations below 0.2 % for major components and below 1 % for minor oxides.
• Accuracy: Average oxide concentrations deviated by less than 0.3 % from certified values, confirming method reliability.
• Analysis speed: Use of the 50 W system achieved full multi-element analysis in 10.4 min; the 200 W upgrade further accelerates throughput without compromising performance.

Benefits and Practical Applications

• High spectral resolution and stability enable precise quantification of trace oxides and major components in complex ore matrices.
• Minimal sample preparation and maintenance lead to low operating costs and high laboratory throughput.
• Broad elemental coverage supports comprehensive process and quality control in mining, beneficiation, and refining.

Future Trends and Opportunities

• Integration of higher-power WDXRF units for sub-minute analysis to support real-time process monitoring.
• Development of portable WDXRF instruments for on-site ore grading and exploration sampling.
• Application of advanced chemometric and machine-learning models for rapid data interpretation and predictive maintenance.

Conclusion

The ARL OPTIM’X WDXRF Spectrometer provides a robust, accurate, and efficient solution for nickel ore analysis. Demonstrated calibration linearity, excellent repeatability, and rapid measurement cycles make it well suited for routine quality control in mining and metallurgical laboratories.

Reference

No external literature references were provided in the original application note.