EFFECT OF (N,GAMMA) AND (N,ALPHA) REACTIONS OF FRAMEWORK ATOMS ON THE (N,GAMMA) RECOILS IN BA AND CS CATIONS IN HIGH-SILICA ZEOLITES

The effects of (n, gamma) and (n, alpha) reactions of framework atoms on the fate of (n, gamma) recoil species Ba-131(2+) and CS-134(+) from Ba2+ and Cs+ loaded in high-silica aluminosilicate and borosilicate zeolites (boron-zeotypes) have been studied. Studies were made of the recoil from "open to locked-in" and "locked-in to open" sites. In open to locked-in recoil, target ions were eluted with eff iciencies of 90% where only (n, gamma) processes were in operation, but in the presence of (n, gamma) and (n, alpha) reactions, the efficiency fell to 80%. For locked-in to open site recoil, the corresponding efficiencies were in the ranges 50-60% and 40-50%. The effect of calcination temperature on the exchange of cations present was also ascertained. The high-silica zeolites used were synthesized according to published methods and were characterized by XRD, i.r., SEM, and t.g.-d.t.g./d.s.c. techniques, and all were found to be crystalline. In boron-zeotype materials, the magnitude of (n, alpha) damage was increased by the use of B-10 isotope.