In situ Raman study of wairakite and dawsonite interaction with water at high P–T parameters

Abstract

The behavior of wairakite CaAl₂Si₄O₁₂ · 2H₂O and dawsonite NaAlCO₃(OH)₂ in a water medium is studied by means of in situ Raman spectroscopy at the simultaneously high temperatures and pressures (up to T = 723 K and P = 1 GPa). After the initial minerals are partially dissolved, phillipsite forms in the wairakite–water system, and a glass-like phase is generated in the dawsonite–water system. These minerals show no signs of overhydration. The amorphization of the wairakite structure that occurs at high temperatures and pressures was reversible.