Desenvolvimento de diafragmas poliméricos aplicáveis na produção eletrolítica de cloro-soda.

Abstract

Sodium hydroxide (NaOH) and chlorine are among the most important chemicals in the industry and are produced simultaneously by the electrolysis of brine. The electrolytic cells are composed of a cathodic and an anodic chamber, separated by a diaphragm that allows the ions to pass through ionic migration. Most of the diaphragms use asbestos and the current environmental laws direct for the extinction or replacement of this material. Thus, a study was carried out on the development of alternative diaphragms based on polymeric materials and additives that could replace asbestos and enable its application in the chlorine-soda industry. Therefore, polymeric fibers were used, such as Ultra High Molecular Weight Polyethylene (PEUAPM), which resists the severe conditions of the electrolytic process. It was also necessary to use doping with inorganic fillers (clays) to give less permeability to the diaphragms. In view of this, systems were developed for depositing and characterizing the diaphragms that enable reproducibility and adequate analysis compared to the industrial scope. Starting from an experimental planning of mixtures with 5 different fibers, it is possible to evaluate which diaphragm composition favored the best results in the electrolysis parameters. The results were promising, considering that among the 15 formulations tested, it was possible to reach a composition whose electrochemical properties meet all specifications and can even be applied on an industrial scale.