SOME ASPECTS OF CARBONIZATION OF MIXTURES CONTAINING COAL-TAR PITCH AND GRAPHITE FECL3 COMPOUNDS

Pyrolysis of coal tar pitch has been carried out with new added species: a first-stage FeCl3 graphite intercalation compound (GIC). Small particles of graphite were used (average diameter almost-equal-to 5 mum) with the aim of obtaining a good distribution of the particles within the pitch matrix. Contrary to many works described in the literature, FeCl3 intercalation in such small particles does not need stringent conditions for first-stage synthesis. Many hk0 reflexions of the FeCl3 lattice are observed by X-ray diffraction; the incommensurability of the two macromolecular lattices (graphite and intercalated FeCl3) is well characterized. The coal tar pitch-GIC mixture (4% in volume) presents a good distribution of the particles, as confirmed by scanning electronic microscopy (SEM). X-ray measurements show that the GIC particles are not deintercalated during the thermal treatment of mixing. Pyrolysis was carried out at 550-degrees-C with a heating rate equal to 20-degrees-C/min. The green coke yield obtained after this treatment is higher than in the case of a pure coal tar pitch pyrolysis, and new species containing iron are characterized in the green coke matrix. A partial diffusion of this element out of GIC particles occurs during the thermal treatment, and the released iron is reduced to oxidation degrees 2 and 0.