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Pollution Prevention and Control Technologies for Plating Operations
Section 3 - Chemical Recovery
3.6 ELECTRODIALYSIS
3.6.3 Applications and Restrictions
The application of electrodialysis for recovery of nickel plating chemicals is shown in Exhibit 3-49. This application, which includes a material balance, was taken from the literature (ref. 32), and is based on an actual case study performed by an electrodialysis equipment manufacturer. The work for this application was performed at a job shop with an automatic nickel barrel plating operation. The plating and rinsing configuration used prior to the implementation of electrodialysis is also shown. Based on a comparison of the two diagrams, the electrodialysis system recovered approximately 38 lbs of nickel per day more than the existing drag-out/drag-in recovery rinsing system. The difference in plating tank evaporation rates between the original and revised systems was not discussed in the article, but presumably was due to a change in the operating temperature of the bath.
Most applications for this technology have involved nickel recovery including Watts, sulfamate and bright nickel plating solutions and nickel galvanizing. Other applications identified by vendors include: gold, copper, cadmium, platinum, silver and zinc cyanide; tin-lead, palladium, zinc phosphating and zinc galvanizing (ref. 134, Kinetic Recovery Corporation file, Graver Co. file).