Análisis de la transformación del caolín de Hidalgo en zeolita cancrinita y fases secundarias por el método hidrotermal

This study investigated the transformation of cancrinite-type zeolite, together with secondary phases, in a hydrothermal system. The mineral kaolin and NaOH were used as precursors under self-generated pressure at 140 °C, varying the reaction time at intervals of 0 to 10 hours. The kaolin, the main precursor, was subjected to X-ray diffraction (XRD), elemental chemical composition (XRF) and Fourier Transform IR Spectroscopy (FT-IR) analyses. The resulting solids were characterized by XRD. Initially, crystalline phases such as Na-P2 zeolites, gismondine, analcime, natrolite and sodalite were formed, but with time they became unstable and dissolved to form new phases. At 8 hours of reaction, the cancrinite zeolite predominated, fulfilling the main objective of the study. The solid material was analyzed by scanning electron microscopy (SEM) and FT-IR. The behavior of Na, Si and Al in the solutions was evaluated over time by inductre coupled plasma (ICP). It was conclusively demonstrated that kaolin from Hidalgo is a feasible precursor to synthesize zeolites, cancrinite type as predominant phase in 8 hours at 140 °C, using moderate concentrations of NaOH.