Influence of process parameters in microwave continuous synthesis of zeolite LTA

In this work, zeolite LTA was obtained by a microwave continuous synthesis process. The feasibility of such a process, which could have some interesting advantages, needs, however, a better understanding and also better study of the involved parameters. Some of these have been investigated, such as the effect of the seeds addition in the gel, the varying of the microwave output power and the use of different reactor geometries. Results demonstrated that the preliminary gel nucleation is a fundamental step for the microwave zeolite crystallization as well as the output power management. A coiled pipe and a spherical vessel used as continuous reactors showed a different behaviour in similar synthesis conditions, confirming the relevance of the geometrical distribution of matter in the microwave cavity and the generated electromagnetic field distribution. The relative influence of microwaves, of seeding and of fluidodynamic conditions was not only evident in terms of final product crystallinity but also in particle size and distribution, as confirmed by the morphological analysis.