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 that different cations may influence their mechanical stability. To prove this assumption, the influence of the partial exchange of sodium ions 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. Analysis of the experimental results has shown that a partial exchange of sodium with Li+, K+, Cs+, and NH4+ does not affect the basic mechanism 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(Na+, NH4+).