The use of attapulgite clays as a dopant in the development of diaphragms polymers for application in the electrolytic production of chlorine - soda

Among the electrochemical processes used in the electrolytic production of chlorine (Cl2) and caustic soda (NaOH), diaphragm technology is the most widely used in the world. This work aimed to develop polymeric diaphragms compared to the Tephram® commercial diaphragm. Eleven diaphragms doped with three types of attapulgite clays. The clays were submitted to the characterization: granulometric, chemical and mineralogical. The polymeric diaphragms were characterized by the measurement of thickness, permeability and resistivity. Those that presented the best results of these properties had their electrochemical performance analyzed. The obtained results show that the diaphragms studied in this work with 75% of clay presented the best properties. Among these, the D4 diaphragm with 75% Basf attapulgite presented closer results when compared to Tephram® obtaining a soda concentration of 15,36 g/l and the lowest sodium chlorate content in the cell liquor liquor (0,33 g/l). (author)