Fluorescence technique - its application for better prediction of properties for certain Indian coals

Abstract

In the course of a study of the prediction of chemical and carbonization properties of Indian caking/coking coals from their petrographic characteristics, certain high-volatile, high-fluid Indian caking coals of the Permian and Tertiary periods did not respond well to these predictions. These coals have so far been referred to as ‘abnormal’ coals, because they show chemical and carbonization properties, not in agreement with their rank and micropetrographic characteristics as observed under normal white light. They also show abnormally high fluidity, swelling indices and/or coke types. This leads to the conclusion that these coals contain certain microcomponents high in hydrogen, with a high volatile content and not easily identifiable under the normal white light microscopy. Three ‘abnormal’ coals (two Permian and one Tertiary) were studied both under normal white light and under fluorescence light. It was observed that the coals contain different types of fluorescing bituminous matter, generated in the coal during the coal-forming process itself, which influences the chemical and carbonization properties to a great extent. In solving coal-utilization problems such applied coal microscopic studies both under normal white light as well as under blue light irradiation would be of great help.