The Effect of HCl and NaOH Treatment on Structural Transformations in a Ball-Milled Anthracite after Thermal and Chemical Processing
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.
A. D. Lueking et al., "The Effect of HCl and NaOH Treatment on Structural Transformations in a Ball-Milled Anthracite after Thermal and Chemical Processing," Carbon, vol. 45, no. 11, pp. 2297-2306, Elsevier, Oct 2007.
The definitive version is available at https://doi.org/10.1016/j.carbon.2007.04.027
Chemical and Biochemical Engineering
Consortium for Premium Carbon Products from Coal
Pennsylvania State University. Energy Institute
Pennsylvania State University. Material Research Institute
Keywords and Phrases
Ball milling; Carbon; Hydrochloric acid; Nanocrystalline materials; Olefins; Sodium compounds; Chemical processing; NaOH treatment; Structural transformations; Thermal processing; Anthracite
International Standard Serial Number (ISSN)
Article - Journal
© 2007 Elsevier, All rights reserved.
01 Oct 2007