The effect of HCl and NaOH treatment on structural transformations in a ball-milled anthracite after thermal and chemical processing

Angela D. Lueking, Humberto R. Gutierrez, Puja Jain, Dirk T. Van Essandelft, Caroline E. Burgess-Clifford

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16 Scopus citations

Abstract

Nanocrystalline diamond (NCD) was observed after reactive ball milling of anthracite coal with cyclohexene, a high-temperature (1400 °C) thermal anneal, and a 4 M HCl treatment followed by a 10 M NaOH treatment. A crystalline carbon region was also observed when the thermal anneal was omitted. This crystalline region is highly unstable and converts to NCD and carbon onions via electron irradiation in the TEM. X-ray diffraction, Raman, ash content, and temperature-programmed oxidation (TPO) data suggest that tetrahedral amorphous carbon is formed during milling, iron carbides are formed during the thermal anneal step, and both the HCl and NaOH purification steps lead to changes in carbon structure. NaOH oxidizes metal carbides and this process may contribute to NCD formation.

Original languageEnglish (US)
Pages (from-to)2297-2306
Number of pages10
JournalCarbon
Volume45
Issue number11
DOIs
StatePublished - Oct 1 2007

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)

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