Influence of the mineral matter content on the rate of heat release from Turkish lignites

In this study, combustion curves of twenty-five original and demineralized Turkish lignite samples were obtained through use of a differential thermal analyser. The lignite samples were demineralized by treatment with hydrochloric and hydrofluoric acids. Samples of 20 mg were heated up to 1074 K at a constant rate of 10 K min^–1 in a 40 cm³ min^–1 flow of dry air. The rates of heat release from the original and demineralized samples were compared and are discussed.