Ion-exchange techniques were used to study the diffusion of 42K in natural chabazites. The diffusivity at 20 to 60C could be described by:

D(m2/s) = 1.5 x 10-10exp[-29.7(kJ/mol)/RT]

N.M.Brooke, L.V.C.Rees: Transactions of the Faraday Society, 1969, 65[562], 2728-39