Determination of Lc in calcined petroleum coke according to ASTM D5187 with ARL EQUINOX 100 X-ray diffractometer

Význam tématu

This section highlights the importance of determining the crystallite size in calcined petroleum coke (CPC) as it directly affects the electrical conductivity and performance of electrodes used in the metal smelting industry.

Cíle a přehled studie

The study aims to evaluate the mean crystallite height (Lc) of CPC material by applying X-ray diffraction (XRD) analysis following Rietveld refinement methods (MAUD and JADE) and the simplified Scherrer approach outlined in ASTM D5187.

Použitá metodika

The CPC sample was analyzed in reflection mode under Cu Kα radiation (λ = 1.541874 Å) for a total acquisition time of 2 minutes, with the specimen rotating during measurement. The full width at half maximum (FWHM) of the graphite [002] diffraction peak was extracted to calculate Lc.

Použitá instrumentace

• Thermo Scientific ARL EQUINOX 100 X-ray diffractometer
• Custom-designed micro-focus X-ray tube (Cu 50 W or Co 15 W) with mirror optics
• Curved position sensitive detector (CPS) enabling simultaneous real-time detection of diffraction peaks
• Portability without the need for external water cooling

Hlavní výsledky a diskuse

The mean crystallite sizes calculated by Rietveld refinement were 48.1 Å (MAUD) and 42.0 Å (JADE), while the ASTM D5187 method yielded 18.5 Å. The discrepancy arises from differences in peak-profile algorithms and sensitivity of FWHM determination. Overall, all methods produced consistent trends for CPC quality assessment.

Přínosy a praktické využití metody

This approach delivers a rapid and reliable evaluation of CPC crystallinity to support electrode production quality control. Its portability facilitates inter-laboratory measurements without significant infrastructure. The method aids in optimizing smelting efficiency by ensuring material consistency.

Budoucí trendy a možnosti využití

Future developments may include enhanced micro-strain correction in refinement models, integration of automated data analysis workflows, real-time monitoring during CPC production, and application to other carbon-based materials in energy and materials research.

Závěr

The ARL EQUINOX 100 diffractometer, combined with Rietveld and ASTM D5187 analysis protocols, is an effective tool for determining the crystallite size in CPC. Its fast data acquisition, accuracy, and portability make it well suited for routine industrial and research laboratories.