Process Options for Waste Minimization and Metal Recovery for the Metal Finishing Industries

There is growing environmental concern with the methods of waste disposal used for handling hazardous materials in the metal finishing industry. A resulting need exists to develop and implement the best existing and potential technologies for waste minimization and resource recovery. The objectives of this study were to identify and briefly describe both existing and potential future methods for minimizing and recovering metallic wastes in the metal finishing industries. Included in the evaluation are the advantages and disadvantages of the various methods available and under development. Existing minimization techniques include countercurrent rinsing, drag-out reduction, and waste segregation. Recovery methods investigated include evaporation, ion exchange, reverse osmosis, electrodialysis, and re-smelting of metallic wastes. Discussions on future methods also cover combination technologies with the trend toward development of closed-loop processes. Investigation has shown that additional research must be done to make the developing technologies economically feasible. These challenges are being met by increasing contributions from the technical community, particularly chemical engineers. Finally, the metal finishing industries must be willing to join in the development and implementation of these new technologies if we are to successfully answer environmental concerns.