Abstract
The purpose of the present study is to clarify the differences in the carbon structure of cokes derived from coking coals and non-coking coals. The structures of the carbonized coals at 1000°C were estimated from the X-ray diffraction and Raman spectroscopy measurements of the carbons heat-treated at 3000°C. This was based on the conventional recognition in carbon science such that the structures of carbons become obvious after heat-treatments at graphitization temperature, 3000°C. Three polymers and five coals confirmed the above recognition from the analyses of the carbons prepared at different temperatures. Essentially, coking coals and non-coking coals could be classified to graphitizing and non-graphitizing carbons, respectively. By close inspections of carbon (002) X-ray diffractions of 3000°C treated coals, it was found that the degrees of graphitizing and non-graphitizing abilities of coals were not as complete as the typical polymer-derived carbons. The Raman spectra of the carbons from non-coking coals prepared at 3000°C revealed the inhomogeneous structures of the carbons, because they gave position-dependent Raman spectra. Structural models of the cokes from coking and non-coking coals by taking account of continuous self-dissolving model were proposed. The important point of the model is that cokes consist of ordered matrix and disordered 'islands' in the matrix. The differences between the coking coal-derived ones and the non-coking coal-derived ones are found in the size and the distribution of the disordered islands.
