Analysis of sand and feldspar by X-ray fluorescence

Importance of the Topic

Sand and feldspar serve as critical feedstocks in glass and ceramics production. Accurate oxide analysis—especially of SiO2, Al2O3, and Na2O—is essential to control material properties and ensure product performance. X-ray fluorescence provides a fast, nondestructive means to achieve this.

Objectives and Study Overview

This application note evaluates the ARL OPTIMX WDXRF spectrometer’s performance for sand and feldspar analysis, focusing on detection limits, measurement precision, and workflow efficiency.

Methodology and Instrumentation

• Sample Preparation
  • Pressed pellets of sand and feldspar with 4% binder for routine analysis
  • Fused beads for enhanced accuracy but higher detection limits
• Instrumentation
  • Thermo Scientific ARL OPTIMX 50W WDXRF system with Rh end window tube and SmartGonio
  • Crystals and detectors: AX06, PET, LiF200, flow proportional counter

Main Results and Discussion

• Limits of Detection
  • Fe₂O₃, TiO₂, K₂O: ~7–9 ppm at 80 s counting time
  • Al₂O₃, P₂O₅: up to 35 ppm
  • Na₂O: 75 ppm at 80 s; dedicated fixed channel reduces measurement time and improves precision
• Precision Tests
  • Sand sample: relative standard deviations below 1% for major oxides over three days
  • Feldspar sample: comparable repeatability, confirming method robustness
  • SmartGonio vs fixed channel for Na: total analysis time reduced from 4 min 10 s to 2 min 10 s with similar precision

Benefits and Practical Applications

• Rapid routine elemental analysis with minimal sample preparation
• High repeatability supporting QA/QC in glass, ceramics, and geological labs
• Capability to quantify major and minor oxides in a single measurement

Future Trends and Opportunities

• Integration with automated sample handling for high-throughput workflows
• Next-generation monochromators to further lower detection limits for trace elements
• Extension of WDXRF applications to diverse industrial and environmental materials

Conclusion

The ARL OPTIMX 50W WDXRF spectrometer demonstrates low detection limits and excellent precision for sand and feldspar oxide analysis. Flexible measurement configurations and efficient workflows make it well suited for industrial quality assurance and research laboratories.