Technical Paper: Purification And Recovery Of Anodizing Baths And Bright Dip Rinse Water

By Paul Pajunen, Eco-Tec Inc.

The recent punishing and dramatic increases in sulfuric acid and phosphoric acid prices have prompted many anodizers to investigate the implementation of acid recovery and purification techniques. A well-established method of anodizing bath purification employs a process called resin sorption. Not only is sulfuric acid costs reduced, but other benefits include a predictable, consistent bath operation resulting in improved product quality and productivity enhancements. This presentation will review the resin sorption process, outline critical design features and parameters, and provide field performance data and operating experiences of resin sorption installations for sulfuric acid anodizing purification and phosphoric acid recovery.