Sodium recovery with chloride removal from electrostatic precipitator catch at coastal and/or closed-cycle mills using bipolar membrane electrodialysis

A new approach for recovery of sodium with removal of chloride from the electrostatic precipitator (ESP) catch at coastal and/or closed-cycle mills is examined. A three-compartment bipolar membrane electrodialysis (BME) system, incorporating monovalent anion-selective membranes, is used to split the sodium chloride content of the ESP catch into caustic soda and hydrochloric acid. A pretreatment stage was required to produce a feed solution compatible with the operating constraints of the BME system. Application : examines the feasibility of bipolar membrane electrodialysis as a means of recovering sodium and removing chloride from the kraft recovery cycle.