A Criterion for Selecting Leach Test Specimen Sizes

When leaching is controlled by a diffusion process, leach test results are particularly simple to interpret when test specimens approximate semi-infinite media. For spherical and cylindrical leach test samples, a criterion relating the test duration T, the specimen radius R, and the effective bulk diffusion coefficient D, to the desired degree of concurrence to the semiinfinite geometry behavior P, is shown to be given by: From the proposed criterion, it is concluded that, for glass waste forms, the semi-infinite geometry approximation is met by most test samples except possibly for finely crushed material