Carbon and Sulfur Determination in Limestone/Dolomite (CS744)

Importance of Topic

Limestone and dolomite are foundational industrial minerals with applications ranging from construction aggregate and fluxing agents to acid neutralization and animal feed. Reliable determination of total carbon and sulfur content is critical for quality control and regulatory compliance across mining, cement, agriculture and environmental sectors. Accurate measurement ensures material consistency, optimizes processing and reduces downstream costs.

Objectives and Study Overview

This application note presents a validated procedure for quantifying total carbon and sulfur in limestone and dolomite using the LECO CS744 combustion analyzer. Key goals include establishing method parameters, demonstrating precision and accuracy with reference materials, and outlining a workflow suitable for routine laboratory operation.

Methodology and Instrumentation

The method employs high-temperature induction furnace combustion under oxygen flow to convert carbon to CO2 and sulfur to SO2. Gas detectors measure evolved gases, and concentrations are calculated relative to calibration standards.

• Instrument: LECO CS744 sulfur by combustion analyzer
• Reaction crucibles: Ceramic (preheated at ≥1000 °C)
• Accelerators: Iron powder and vanadium pentoxide
• Flux: LECOCEL
• Oxygen purity, furnace power and timing controlled via touchscreen

Main Results and Discussion

Typical analyses of NIST and LECO Certified Reference Materials (LCRM) yielded:

• Limestone: Carbon ~10.98 % ±0.01 %, Sulfur ~0.121 % ±0.003 %
• Dolomite: Carbon ~12.55 % ±0.05 %, Sulfur ~0.020 % <0.001 %
• Calcium carbonate LCRM: Carbon ~12.01 % ±0.02 %, Sulfur ~0.003 % <0.001 %

Precision across replicate measurements was within 0.1 % relative for carbon and under 5 % relative for low-level sulfur, demonstrating method robustness. Calibration with linear forced-through-origin curves provided accurate quantitation across the target range.

Benefits and Practical Applications

This combustion method offers:

• Wide dynamic range for carbon and sulfur detection
• High throughput with minimal sample preparation
• Reproducible results suitable for regulatory reporting
• Compatibility with routine QA/QC workflows in mining, cement and environmental labs

Future Trends and Opportunities

Advancements in sensor technology and data integration promise further improvements in detection limits and automated quality assurance. Coupling combustion analysis with real-time process control and machine-learning models could enhance predictive maintenance and material traceability across the supply chain.

Conclusion

The LECO CS744 induction furnace method provides a reliable, user-friendly solution for total carbon and sulfur determination in limestone and dolomite. It delivers high precision and accuracy, supporting critical quality control operations in diverse industrial settings.

Reference

LECO Corporation. Carbon and Sulfur Determination in Limestone/Dolomite Application Note; Form No. 203-821-545, 2019.