MECHANOCHEMISTRY OF ZEOLITES .4. INFLUENCE OF CATIONS ON THE RATE OF AMORPHIZATION OF ZEOLITE-A BY BALL-MILLING

Based on previous mechanochemical studies of zeolites it was assumed t hat different cations may influence their mechanical stability. To pro ve this assumption, the influence of the partial exchange of sodium io ns from zeolite A by other cations (Li+, Na+, K+, Cs+. and NH4+)on the kinetics of amoprhization was investigated. X-ray diffractometry and FT i.r. analysis were used to characterize the effect of the exchange on the rate of amorphization of zeolite A during its ball milling. Ana lysis of the experimental results has shown that a partial exchange of sodium with Li+, K+, Cs+, and NH4+ does not affect the basic mechanis m of the amorphization process, but only the rate of amorphization, R. The decrease of R in the sequence R(Na+) > R(Li+, Na+) > R(Na+, K+) > R(Na+, Cs) > R(Na+, NH4+) was explained by the increase of the volume , V-oc, occupied in a unit cell of zeolite A by the cations (Na+ + R()) in the sequence V-oc(Na+) < V-oc(Na+, K+) < V-oc(Na+, Cs+) < V-oc(N a+, NH4+).