Heat-acid treatment of georgian and kazakhstani natural heulandite-chabazites

Abstract

The article considers the processes leading to a change in the structure and properties as a result of thermal treatment followed by acid treatment of natural zeolites from the Rkoni plot of the Tedzami deposit, Georgia, containing up to 80% of heulandite and 10% of chabazite, and from the Chankanay deposit, Kazakhstan, containing up to 70% of heulandite-chabazite mixture, selected for the creation of new bactericidal zeolite filter materials for purification and desinfection of water from various sources. The influence of preliminary heat treatment of the studied natural zeolites on weight loss, the processes of dealumination and decationization during subsequent acid treatment, and the adsorption properties of the final products is described. It has been shown that mass loss is minimal for amorphized samples, dealumination and the participation of sodium ions in the decationization process slow down significantly, and the adsorption capacity for water and benzene sharply decreases with increasing calcination temperature; all these effects are clearly pronounced for heulandite-containing Rkoni tuff, and for the more acid-resistant Chankanay zeolite they are manifested to a lesser extent.