A methodology for quantifying sodalite and cancrinite phase mixtures and the kinetics of the sodalite to cancrinite phase transformation

A simple methodology for determining the cancrinite proportion of a sodalit e and cancrinite phase mixture was developed using powder X-ray diffraction . Using this :methodology to quantify phase mixtures, the kinetics of the s odalite to cancrinite phase transformation were determined. The transformat ion reaction leading to cancrinite formation was found to be first order wi th respect to the relative concentration of sodalite. Over the temperature range 160-240 degrees C, an activation energy for this process was estimate d to be 133 kJ mol(-1). The techniques of Si-29 MAS NMR and FTIR were both found to be unsuitable for quantifying dimorphic phase mixtures due to the ambiguity of the results they produced. (C) 1999 Elsevier Science B.V. All rights reserved.