Study relating to temperature stability of the Natural Laumontite Zeolite

On the basis of the DTA measurements, the natural laumontite zeolite has been subjected to thermal decomposition at temperatures of 20, 250, 420, 580, 750, and 1000°C. The decomposition products were identified by the X‐ray powder method (CuK α‐ ) and IR spectroscopy (Nujol). It has been determined that the crystal structure of laumontite is stable up to the temperatures of 250°C. The dehydration of the mineral that takes place has three phases. With the increasing temperature, besides the conserved laumontite basic lattice (up to 420°C), a new phase “X” (paraleumontite) is produced. At 1000°C the laumontite is transformed in anorthite. The following phenomena correspond to dehydration: The intensity decrease of the OH stretching vibration, vanishing of librations and H 2 O bending vibrations. The remaining water is hydrolytically split up and forms structural OH‐groups which partially outlast up to 1000°C.