Mapping of Greek zeolite deposits (IGME) and full characterisation of raw materials (IGME, CSTB)
Bulk samples were taken from various zeolite deposits in Evros and Rhodopi Prefectures, Thrace, NE Greece. The criteria for the zeolite deposits selection were the size of the deposit, the type of zeolitic alteration and the knowledge status of each deposit. According to their chemical assays, zeolitic tuffs are characterized as rhyodacitic to dacitic in composition. The collected samples of altered tuffs, according to zeolite type prevailing, can be classified in tuffs altered to (a) Clinoptilolite , (b) Heulandite-2 +/- mordenite, (c) Mordenite, (d) Analcime.
Due to their mineralogical composition, C.E.C. of the working samples range from deposit to deposit. The main exchangeable cation is calcium, except in the case of Petrota. This is attributed to the Na-rich clinoptilolite being its main alteration mineral, whereas in the other tuffs alteration to Ca-rich heulandite-2 prevails. All working samples show similar behaviour in thermal treatment. Almost in all of them, the weight loss has been achieved at a temperature lower than 500oC. During quick thermal expansion at various temperatures, some mineralogical changes, as well as formation of new minerals take place.
The samples for industrial applications were collected from Pentalofos. Chemical composition of selected zeolite for the four production tests is almost the same and their moisture depends on ambient temperature. CSTB measured physical properties (Water vapour adsorption/ desorption, VOC adsorption, density, porosity etc) of four families of Greek natural zeolites.