ALENCO extrudes and paints aluminum for the building products industry. The extrusions were conversion coated with hexavalent chromium prior to painting to enhance the adhesion between the coating and the aluminum. In 1991, ALENCO made a corporate decision to eliminate chromium from its operation. After extensive testing, a zirconic acid system was selected. The equipment was modified and additional equipment installed in December 1991. On-line testing began in January 1992. Production began in June 1992. To date, in excess of 45 million pounds of aluminum have been successfully coated with this system.
The technology of replacing chromium with zirconium is not new. Some formulation modifications were necessary to improve flow and provide more uniform drying. Other minor application changes were also required. The major factor in the success of this project was the corporate decision to make it happen.
The process eliminated the use of hexavalent chromium that had to be converted to trivalent chromium to be acceptable for disposal. The conversion was costly and produced over 160 cubic yards of waste to be landfilled. The potential liabilities were enormous. The change to the zirconic acid system eliminated the use of chromium, its associated waste streams and its liabilities.
Details of Reductions
Additional Information :
Modifications to the existing system cost $60,000. Disposal cost savings for the first year were $60,000. Return on investment was one year. With constantly increasing disposal costs, the economic benefits are clear.