Electrodialysis for bleach effluent recycling in kraft pulp production: Simultaneous control of chloride and other non‐process elements

Abstract In the United States, more than 50 million tons of kraft pulp are produced per year. A strong effort by kraft pulp producers has been under way for several years to reduce water use. The in‐process recycling of the acidic bleach effluent carrying metals, transition metals, calcium, and often large amounts of chloride is still a significant challenge. The simultaneous selective removal of chloride, and detrimental cations from the acidic bleach effluent of bleached kraft pulp mills by electrodialysis was investigated. The laboratory results with actual effluents show that very good removal levels can be achieved in an economical process. The chloride removal from acidic bleach effluent will aid significantly in keeping chloride levels acceptable in the recovery cycle.