Chars from the co-carbonisation of a low-rank coal and olive stones have been used to prepare environmental acceptable smokeless fuel briquettes. The blend was a mixture of char, molasses and H3PO4. This acid was added to favour the polymerisation of the binder. The effect of the curing temperature on the physico-chemical features of the briquettes was studied by Fourier Transform Infrared Spectroscopy and Temperature Programmed Decomposition followed by Mass Spectrometry. The presence of H3PO4 as well as the curing process at 200 degreesC of temperature, contribute to the formation of carboxylic acids which lead to the production of briquettes with adequate mechanical properties. (C) 2003 Published by Elsevier Science Ltd.