Industrial applications of the dolomite from Potamia, Thassos Island, N. Aegean Sea, Greece

The examined dolomite is composed of 98% of mineral dolomite and 2% of calcite. Other silicates (i.e. quartz) exist only in trace amounts. This dolomite presents intense orange luminescence colour, indicating the absence of impurities and thus high purity. Its chemical composition is: CaO = 32.9%, MgO = 20.2%, CO2 = 46.7%, others = 0.14% and its isotopic composition is delta O-18 = -3.10 parts per thousand and delta C-13 = +3.40 parts per thousand. These values indicate that this dolomite has been formed mainly by recrystallisation of pre-existing limestone with simultaneous or subsequent partial substitution of CaCO3 by MgCO2 (dolomitisation). The data of its most important physicochemical properties are: water absorption = 0.2%, water dissolution = 0.17%, surface area = 1.10 m(2)/g, pH = 10.0, oil absorption = 24 ml/100 g and brightness = 97%. These data satisfy almost all the quality demands for use of its wastes after processing for the production of many industrial products. The most significant fields of use of the dolomite from Potamia, except its main world-wide demand as decorative stone, may be: as filler, whitening, and extender product in many paper, paint, and rubber industries; in addition, it can be used for the production of fertilisers.