A New Method for Measuring the Graphite Content of Anthracite Coals and Soots

Abstract

A new method for estimating the average fraction of graphitic structure (the graphite-like factor) found in carbonized materials such as anthracitic coals and soots has been developed. This method employs a Q meter, a device that can be used to measure the resistance of a coil at high frequency. The resistance, and therefore the Q response, depends on the conductive behavior of the delocalized electrons in the sample placed inside a RF coil. On the basis of the Q measurement, one can estimate the percentage of the sample that contains graphite-like regions in which delocalized conduction electrons exist. A series of measurements was made on a set of graphite and silica gel mixtures in order to calibrate the measured Q values. This method was then applied to a series of anthracitic coal samples and a number of soot samples. The Q values obtained were related to the graphitic content of the soot or coal. These results are compared with carbon-13 NMR data and ESR unpaired electron spin concentration measurements.