Chemistry of soil minerals. Part VI. Salt entrainment by sodalite and cancrinite during their synthesis

Abstract

The imbibition of salts by sodalite and cancrinite during their hydrothermal formation from kaolinite has been studied. Isotherm contours recalling those of Langmuir's isotherm were observed in sodalite for NaCl, NaBr, NaClO₃, NaClO₄, and Na₂CO₃. These results have been interpreted in terms of a Donnan equilibrium, in which solid-phase activities were calculated on the experimentally justified assumption that each sodalite cage is capable of accommodating a particular number of each kind of guest molecule, which number varies with the size of the guest. The stoicheiometry, thermal stability, chemical reactivity, and crystallization kinetics of representative compounds have been discussed, and the possible importance of salt inclusion in other zeolitic materials has been noted.