The effect of calcination on reactive milling of anthracite as potential precursor for graphite production

The effect of a pretreatment using reactive ball milling and calcination on the graphitizability of an anthracite coal is explored. A thermal anneal of Buck Mountain anthracite at 1400 °C in argon increased the Lc crystallite dimension (from 12 to 20 Å) and led to an increase in the oxidation temperature of the product. Ball milling of the coal reduced particle size with a nominal effect on carbon order and the degree of graphitization after the 1400 °C thermal anneal (Lc from 18 to 29 Å). Ball milling in cyclohexene led to a substantial increase in the graphitizability at 1400 °C (Lc from 12 to 50 Å). The enhanced reactivity was due to both carbon structure and introduced metal. The products of the mechano-chemical pretreatment and thermal anneal consisted of nanographene ribbons and multi-walled nanopolyhedral particles. It oxidized at moderate temperatures and had a high (74.3%) degree of graphitization based on X-ray diffraction analysis; the derived material has potential as filler for production of graphite.