A STUDY OF COAL-METAL COMPLEXES BY THERMAL-ANALYSIS

Coal-metal complexes obtained by dynamic sorption of cations from water solution on sulphonated and oxidized coals. Complexes with the following cations were produced: Mg, Ca, Zn, Cd, Ba, Cr. Fe, Co, Ni, Cu, Pb and Ag. DTA curves of sulphonated coal and sulphonated coal-metal complexes are distinct and can be divided into three groups on the basis of shape and peak temperatures, the main influence being the type of chemical bondbetween metal cation and functional group of the coal. For metal complexes with oxidized coal the main exothermic peak shifts either to higher of lower temperatures, depending on the nature of the cations. The presence of metal chemically bound to carboxylic- and sulpho-groups of the coal causes additional thermal effects to appear on the DTA curves.