Study of the mechanism of changes in electrical resistance when heating caking and noncaking coals

Electrical resistivity, permittivity and X-ray structural characteristics are determined for solid residues after thermal destruction of caking and noncaking coals within a temperature range of 200–800 °C. The run of curves for changes of electrical resistivity depending on temperature is explained by analogy with the mechanism for changes of electrical resistance in high-molecular compounds. From peculiarities of structure of solid carbonised residues, it is shown that transport of electrical charges through a sample consists of several steps.