[Structural and property characteristics of Chinese fir wood charcoal prepared under various conditions].

By techniques of one-step and two-step carbonization, and capped and uncapped carbonization, the pyrolysis on the thinning wood of Chinese fir, one of the fastest growing tree species in south China, was carried out. With special focus on the variation of Raman spectra and X-ray diffraction analysis of carbonized materials under different carbonization conditions, comprehensive analyses of charcoals were conducted. Results show that, with temperature rising, the graphite-like microcrystal and carbon atoms at the edge of graphite-like microcrystal increase rapidly. As a result, the hexagon carbon plane structure in carbonized material keeps growing. Moreover, the experiments reveal that carbonization condition has great effects on the property and structure of carbonized material, and 700 degrees C is the critical temperature at which the qualitative change of carbonized material occurs. Furthermore, formation and growth of graphite-like microcrystal in carbonized material, two-step method is more beneficial than one-step method, uncapped container carbonization method is better than the capped one, and using air as atmosphere gas is better than using N2. Samples with longer holding time in the process of carbonization enjoy higher graphitization extent.