Carbon and Sulfur in Lime (CS744)

Significance of Topic

Reliable determination of carbon and sulfur in lime is critical for ensuring product quality in industries such as steelmaking, water treatment and construction. Carbon content reflects calcination efficiency and CO₂ reabsorption, while sulfur levels indicate contamination and overall purity. Accurate elemental analysis supports process control, regulatory compliance and end‐use performance.

Objectives and Study Overview

This application note evaluates the LECO CS744 carbon and sulfur analyzer for rapid, simultaneous quantification of these elements in various lime forms (quicklime and hydrated lime). The aim is to establish sample preparation protocols, method parameters, calibration procedures and performance metrics suitable for routine quality control.

Methodology and Instrumentation

Instrument used: LECO CS744 induction furnace with infrared detectors for carbon and sulfur.

Sample preparation:

• Grind lime to a uniform powder passing 100‐mesh (150 µm).
• Dry samples if required by Certificate of Analysis.
• Use ceramic crucibles baked at ≥1000 °C and LECOCEL and iron chip accelerators.

Analysis parameters:

• Purge time: 15 s; analysis delay: 20 s; furnace power: 100 %.
• Integration: carbon 50 s, sulfur 60 s; baseline delays: 2 s each.

Calibration:

• Reference materials: LECO Ore Tailings (502-319), synthetic carbon (502-029) or NIST SRM 2690 Fly Ash.
• Single‐point calibration through origin for both detectors.

Main Results and Discussion

Typical results demonstrate high accuracy and precision:

• Ore tailings: ~1.53 % C (RSD 0.01 %), ~1.10 % S (RSD 0.02 %).
• High‐calcium lime: ~1.41 % C (RSD 0.01 %), ~0.025 % S (RSD 0.002 %).
• Dolomitic lime: ~0.308 % C (RSD 0.004 %), ~0.044 % S (RSD 0.002 %).

Results confirm linear detector response, minimal drift and reproducible performance across replicate analyses.

Benefits and Practical Applications

• Simultaneous multi‐element analysis reduces cycle time and labor.
• High sensitivity and low detection limits support stringent quality criteria.
• Robust sample preparation and automated operation enable high throughput.

Future Trends and Potential Applications

• Integration with autosamplers and laboratory information management systems (LIMS) for workflow automation.
• Advances in detector technology to extend dynamic range and lower detection limits.
• Application of chemometric and machine‐learning tools for predictive quality control and process optimization.

Conclusion

The LECO CS744 analyzer provides a reliable, efficient and precise solution for simultaneous carbon and sulfur determination in lime. The method supports industrial quality assurance programs by delivering rapid results, robust performance and straightforward operation.

Reference

LECO Corporation. Carbon and Sulfur in Lime. Application Note (Form No. 203-821-476), 2014.