| Popis: |
Clinoptilolite from the Zlatokop, Vranje (South Serbia) having the unit cell composition Na O.7 K O.8 Ca 1.9 Mg O.6 ) (change-para-here) (Al 6.5 Si 29.2 O 72 ) 19.7H 2 O was transformed by ion exchange to the K 4 + and Ca 2+ forms. The thermal stability of these cationic forms of clinoptilolite was investigated by X-ray analysis. It was found that K-clinoptilolite is thermally stable even at 1023 K, that NH 4 −clinoptilolite starts losing crystallinity above 773 K, and that Ca-clinoptilolite is thermally the least stable with loss of crystallinity setting in above 423 K. |
