Analysis of metallurgical slags: ARL OPTIM’X WDXRF Sequential-Simultaneous Configuration

Significance of topic

Steel slags generated during iron and steel production require accurate chemical analysis for process control, waste management and material recovery. Slag composition impacts furnace efficiency, refractory life and environmental compliance.

Objectives and study overview

This study evaluates the performance of a low power WDXRF spectrometer (Thermo Scientific ARL OPTIM’X) in sequential-simultaneous mode for rapid multi-element analysis of metallurgical slags. Calibration strategies and stability under repeatability and reproducibility tests are demonstrated.

Instrumentation

The ARL OPTIM’X WDXRF system features a Rh anode X-ray tube, SmartGonio™ covering elements from Al to U, fixed channels for Na and Mg, and OXSAS software for instrument control and data processing. No external cooling is required and spectral resolution exceeds that of conventional EDXRF.

Methodology

Slag samples were crushed, milled to below 50 µm and subjected to magnetic separation to remove metallic residues. Pressed powder pellets were prepared for routine analysis. Calibration employed ten secondary slag standards covering typical oxide concentration ranges. Multi-variable regression in OXSAS established working curves. Stability tests included ten consecutive short-term runs (20 s per element, 140 s total) and long-term reproducibility over 12 hours at 8-minute intervals.

Main results and discussion

Calibration achieved standard errors of estimate (SEE) below 0.35 % for major oxides (Fe₂O₃ SEE 0.27, Al₂O₃ 0.19, CaO 0.33). Short-term repeatability tests yielded relative standard deviations under 0.1 % for most analytes. Long-term reproducibility demonstrated consistent results with minimal drift, confirming instrument stability.

Benefits and practical applications

The ARL OPTIM’X enables rapid, precise multi-element slag analysis with low maintenance and no cooling requirements. Its performance supports quality control in steel production, process optimization, regulatory compliance and resource recovery efforts.

Future trends and opportunities

Enhancements may include fused bead preparation to minimize matrix effects, automated sample handling, advanced chemometric corrections for complex matrices and real-time process monitoring. Integration with AI-driven data analysis could further improve predictive maintenance and operational efficiency.

Conclusion

The Thermo Scientific ARL OPTIM’X low-power WDXRF spectrometer effectively analyzes metallurgical slags with high sensitivity, precision and stability. Optimal sample preparation, particularly fused bead formation, is recommended to achieve best analytical accuracy.