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

Abstract

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 10hours. 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 8hours 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 8hours at 140°C, using moderate concentrations of NaOH.