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 specie s: a first-stage FeCl3 graphite intercalation compound (GIC). Small pa rticles 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 c onditions for first-stage synthesis. Many hk0 reflexions of the FeCl3 lattice are observed by X-ray diffraction; the incommensurability of t he two macromolecular lattices (graphite and intercalated FeCl3) is we ll characterized. The coal tar pitch-GIC mixture (4% in volume) presen ts a good distribution of the particles, as confirmed by scanning elec tronic microscopy (SEM). X-ray measurements show that the GIC particle s are not deintercalated during the thermal treatment of mixing. Pyrol ysis 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 h igher than in the case of a pure coal tar pitch pyrolysis, and new spe cies containing iron are characterized in the green coke matrix. A par tial diffusion of this element out of GIC particles occurs during the thermal treatment, and the released iron is reduced to oxidation degre es 2 and 0.