Determination of Oxygen and Nitrogen in Graphite and Calcined Coke

Significance of the Topic

The accurate determination of oxygen and nitrogen in graphite and calcined coke is essential for ensuring product quality in the steel industry. Controlling gas content prevents unwanted pollutants, maintains structural integrity, and optimizes performance of electrodes and recarburizers in electric arc and blast furnaces.

Goals and Overview of the Study

• Evaluate the LECO TC600 elemental analyzer for simultaneous measurement of oxygen and nitrogen in graphite and calcined coke.
• Assess ease of use, analytical accuracy, and precision for materials with minimal volatile content.

Methodology and Instrumentation

Samples were dried at 125 °C, ground to uniform consistency, and weighed (0.05–0.10 g) into nickel capsules. The semi-automated analysis sequence involves outgassing, high-temperature combustion in a graphite crucible, and detection of evolved gases. Key method parameters include outgas and analysis current settings, delay times, and a blank-calibration routine.

Used Instrumentation

• LECO TC600 Series oxygen and nitrogen elemental analyzer
• Graphite crucibles (776-247, 782-720) and matching electrode tips (611-351-182, 782-721)
• Nickel capsules (502-822) for sample containment
• Graphite powder (501-073) for crucible pre-load and calibration

Main Results and Discussion

• Graphite samples: average oxygen 0.049 % (s = 0.0019), nitrogen 0.006 % (s = 0.0002).
• Calcined coke samples: average oxygen 0.005 % (s = 0.0009), nitrogen 0.003 % (s = 0.0003).

The low standard deviations demonstrate the method’s precision at trace levels. Consistent blank correction and calibration ensure minimal drift and high confidence in results.

Benefits and Practical Applications of the Method

• Simultaneous determination of oxygen and nitrogen reduces total analysis time.
• High accuracy and reproducibility support stringent quality control in steel production.
• Semi-automated workflow and straightforward sample preparation minimize operator errors.

Future Trends and Opportunities

• Expansion of analysis to non-calcined and other carbonaceous materials.
• Incorporation of advanced data processing for real-time quality monitoring.
• Development of portable or on-site analyzers for rapid field testing.

Conclusion

The LECO TC600 series analyzer delivers reliable, precise, and efficient simultaneous measurement of oxygen and nitrogen in graphite and calcined coke. Its robust performance and user-friendly operation make it an invaluable tool for industrial quality assurance. Ongoing advancements may further extend its applications and enhance analytical capabilities.