Analysis of clinker phases with the Thermo Scientific ARL 9900 Total Cement Analyzer X-ray fluorescence system with compact XRD

Importance of the topic

Precise quantification of clinker phases is essential for controlling cement quality and predicting mechanical properties. Traditional methods such as Bogue calculations or microscopy are either indirect or labor-intensive, which hinders real-time process optimization.

Objectives and overview of the study

This study aimed to evaluate the performance of an integrated XRF–XRD system for rapid, on-line quantification of key clinker phases (C3S, C2S, C3A, C4AF) under real kiln conditions. Results were compared with conventional microscopy and Bogue formula calculations to assess accuracy and reliability.

Methodology

A total of 30 industrial clinker samples were collected across different production stages. Granules were milled and pressed into pellets for analysis. XRF measurements provided oxide compositions, and standard Bogue equations generated theoretical phase contents. Integrated XRD data were obtained by measuring characteristic diffraction peaks without additional correction.

Used instrumentation

• Thermo Scientific ARL 9900 Total Cement Analyzer
• Integrated XRF fixed channels with monochromators
• XRD goniometer sharing the same tube conditions under vacuum

Main results and discussion

The integrated XRD system achieved calibration curves for alite (C3S), belite (C2S), aluminate (C3A) and ferrite (C4AF) phases using microscopy-derived nominal concentrations. Key findings included:

• Strong correlation between integrated XRD and microscopy (e.g., C3S quantification), with correlation coefficients exceeding 0.95.
• Poor agreement of Bogue-derived values with microscopy, highlighting neglect of process variables such as cooling rate and mineral grain size.
• Analysis time below four minutes per sample, enabling near real-time monitoring.

Benefits and practical applications

Implementation of the integrated XRF–XRD approach offers:

• Rapid, reliable phase quantification directly in the production environment.
• Enhanced process control through immediate feedback on clinker composition.
• Prediction of early cement strength based on precise C3S measurement.

Future trends and opportunities

Advances may include:

• Automated data processing with machine learning for improved phase discrimination.
• Continuous in-line monitoring and integration with process control systems.
• Extension of methodology to secondary cementitious materials and blended cements.

Conclusion

The ARL 9900 Total Cement Analyzer with compact XRD integration provides accurate, fast, and direct quantification of clinker phases, outperforming traditional Bogue calculations and aligning closely with microscopy. This methodology enables real-time quality control and optimizes cement production processes.