THERMAL-BEHAVIOR OF ANALCIMES FROM 2 DIFFERENT GENETIC ENVIRONMENTS

Hydrothermal analcimes (H-type) and leucite-derived analcimes (X-type) from different Italian localities have very similar XRD patterns but different thermal behaviours. Dehydration of the H-type analcime gives a DTA peak between 350-degrees and 370-degrees-C, whereas the X-type yields a wide band between 235-degrees and 320-degrees-C. Activation e nergy in the H-type analcime is 6.9-7.1 kcal/mole. whilst in the X-typ e it is 5.3 kcal/mole. Such results are of relative value only because they are derived from non-isothermal runs and are strongly affected b y the chosen method of calculation. Both DTA and TG methods provide ev idence for a difference in the H2O bonding energies within the analcim e structure crystallized in different genetic environments.