Electrically Switched ion Exchange for The Removal of potassium to Enhance Water Recycle Opportunities

摘要

Electrically switched ion exchange, an electrochemical separation technique, is beign developed at the Pacific Northwest National Laboratory for ion separations in industrial process and waste streams. ESIX provides an alternative separation method to conventional ion exchange technology. WHile ESIX is being developed for general ion separations[1,2], this paper focuses on the selective removal of potassium cations. Nickel hexacyanoferrate, an ESIX material, is shown to be selective for potassium over sodium with a separation factor of 24. In addition ,NIHCF has bee nstabilized to over 15,000 cycles in a solution of electrostaic precipitator catech. To accurately model the impact of potassium and chloride buildup due to increased recycle of mill effluent streams, new simulation tools have bee nintegrated into winGEMS. Siumlation is then used ot evaluate recycle strategies and how new technoliges like ESIX impact potassium nad chloride levels throughout the mill. The Kraft recovery funace simulation model has been enhanced to handle potassium and chloride compounds. Results fro ma full mill simulation show that using ESIX to treat the precipitator catch fro mthe recovery boiler can lower the potassijm levels in "as fired" black liquor by 35