Document Type	Master's Dissertation
Author	Nyathi, Mhlwazi Solomon
Email	s25480279@tuks.co.za
URN	etd-06112008-134204
Document Title	Catalytic graphitisation of refcoal cokes
Degree	MSc (Chemistry)
Department	Chemistry
Supervisor	Advisor Name Title Prof W W Focke Supervisor
Keywords	refcoal coke carbonisation catalytic graphitisation catalyst graphite
Date	2008-04-23
Availability	unrestricted
Abstract Synthetic graphite is an important industrial material, used in nuclear reactors, electrodes and many other applications. Graphitisation of coke is the solid-state transformation of the disordered carbon atoms into a well-ordered hexagonal graphite structure, requiring temperatures as high as 2 600 ºC. Catalytic graphitisation using metals or metal compounds allows the rearrangement of atoms to occur at lower temperatures. The extent of catalytic graphitisation is markedly dependent on the structural ordering of the parent coke, the catalyst concentration and the reaction conditions. Solvent extraction of coal using dimethylformamide (DMF) as a solvent yields a refined coal solution referred to as Refcoal solution. Cokes of solvent-refined Tshikondeni coal derivatives have been found to be graphitisable. The activity of acetylacetonate and hydroxyquinolinate complexes of Al, Ca, Cu, Fe and Zr for catalysing the graphitisation of Refcoal cokes at 1 600 and 2 000 ºC was investigated. The effect of residence time on the catalytic graphitisation of Refcoal cokes was investigated by heat-treating cokes for two and six hours at 1 600 °C. For iron(III)acetylacetonate, the effect of metal concentrations was studied. Samples were analysed using thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and optical microscope techniques. The results show that calcium(II)acetylacetonate catalyses the graphitisation of Refcoal cokes. The degree of graphitisation increases with an increase in the iron concentration. However, iron promotes localised graphitisation, probably in the vicinity of the catalyst particles. © University of Pretoria 2007 E991/gm
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