Desenvolvimento e avaliação de diafragmas poliméricos para aplicação no processo de produção eletrolítica de cloro-soda.

Abstract

Caustic soda (NaOH) and chlorine (Cl2) are one of the main starting points, as a basic raw material for the chemical industry worldwide. The most widely used technology for the production of these inputs is the electrolysis of brine in diaphragm cells. The diaphragms are separators that allow the passage of ions, but reduce the diffusion of the products, besides separating the gases formed in the anodic and cathodic compartments and are made from asbestos fiber, polymer fibers or a mixture of the two. This work aimed to develop, from an experimental planning of mixing, polymeric diaphragms from four types of microfibers. In this work, the diaphragms were initially synthesized and doped with insertion of arglia attapulgite and characterized as thickness, permeability and resistivity (Nmac) and from the planning it was possible to develop mathematical models that describe the behavior of the fibers on the properties of the diaphragm. 9 diaphragms, called Polymeric Diaphragm (PD), were developed in different microfiber compositions. The diaphragms that presented the best properties were tested in an electrochemical reactor composed of two cells in series developed at the Laboratory of Electrochemical Engineering - LEEq and its capacity of soda concentration, chloride and chlorate contents in the cell liquor and current and efficiency were evaluated. power. The obtained results show that intermediate proportions (62.5%) of MF2 confer the best properties to the diaphragms and from the characterization results the PD1, PD7 and PD8 diaphragms were selected to undergo the electrolysis process. Among the diaphragms under study, PD1 presented the best results regarding the soda concentration (29.44 g/L) and the lowest sodium chlorate content in the cell liquor (0.035 g/L), being favorable to its application in the chlor-soda production process.