Advances in Industrial Energy-Efficiency Technologies
Prepared for:
U.S. Department of Energy
Office of Industrial Technologies
Washington, DC 20585
Produced by:
National Renewable Energy Laboratory
Golden, Colorado 80401-3393
In conjunction with:
Energetics, Inc.
Columbia, Maryland 21046
DOE/CH10093-266
DE94000251
September 1994
As part of its Industrial Waste Program (IWP), the U.S. Department of Energy's (DOE) Office of Industrial Technologies is working with the Boeing Company and Los Alamos National Laboratory (LANL) to investigate metal recovery and recycle processes that could reduce the toxic metal wastes generated by electroplating. The magnitude of these wastes is tremendous-current estimates indicate that about 496,141 tons (450,000 tonnes) of hazardous sludge are produced by electroplating annually.
These large quantities of toxic metal wastes must be treated and disposed of in landfills, which results in the loss of valuable metals, energy resources, and millions of dollars every year. In 1989, Boeing spent an estimated $2 million for the disposal of the 30,871 tons (28,000 tonnes) of metal-ion hydroxide sludges generated by eight plating facilities in the state of Washington alone. Considering that there are more than 10,000 electroplating shops throughout the United States, the cost of handling this waste nationwide is enormous.
In the near future, burial of this waste in landfills will no longer be an acceptable means of disposal at any price. It is now known that burial of metal sludges or solidified metal sludges does not adequately protect the environment from the migration of toxic metals into soil. Consequently, the U.S. Environmental Protection Agency (EPA) recently established regulations that restrict the form and quantity of these metals that may be released for disposal in landfills. Technologies that recover metals from toxic sludges are urgently needed to help the electroplating industry cost-effective meet new environmental requirements.
Photo: Metal recovery processes allow recycling of both metal ions and wastewater. [provided in source document]
Chemicals such as chromic acid, nickel sulfate, and zinc cyanide are amount those used by the electroplating industry to produce decorate and protective finishes on metal and plastic products. In a typical electroplating process, the part to be plated is first dipped into a plating bath containing an aqueous plating solution. Direct-current electricity is passed through the tank, causing metal ions to deposit (or plate) on the part. The plated part is then dragged out of the plating bath and rinsed in a clean water tank to remove excess plating solution and contaminants that could affect the appearance or quality of the finish. An average plating shop produces approximately 55,127 tons (50,000 tonnes) per year of waste rinse water that requires treatment for removal of toxic metal ions and organics.
With support from DOE, Boeing and LANL are working together to evaluate technologies that could potentially separate metal ions from waste rinse water and allow recycling of both metals and water. LANL has evaluated a number of existing technologies, including:
Recycling metal from electroplating will save energy by:
Metal recovery technologies will also reduce hazardous waste production. Every year the average electroplating plant produces about 50 tons (45 tonnes) of hazardous sludge containing 20% heavy metals, and 55,127 tons (50,000 tonnes) of waste and rinse waters containing 200 ppm of heavy metals. Recycling will reduce hazardous sludge, wastewater, and discarded metals by 90%. Subsequently, recovery and recycling technology will cut hazardous waste production by about 45 tons (41 tonnes) per year, and wastewater by about 49,614 tons (45,000 tonnes) per year at every plating facility. Materials used by the recycling process will probably also required disposal of about 2 tons (1.8 tonnes) per year.
Recovering and recycling metals and wastewater will also greatly improve the economies of the electroplating operation. The new technology is expected to drastically reduce both disposal costs and operating costs for the purchase of plating materials. For a typical electroplating plant, the total annual cost for waste disposal and replacing lost metals is $610,000. Total annualized cost for a typical-size electroplating facility with recycling would be $360,000, resulting in a net annual savings of $250,000 per year.
The toxic metal waste management problems experienced by Boeing are being felt throughout the plating industry. Boeing, through its established position in the plating industry, has plans to create an information distribution system using a network of 3500 electroplating subcontractors and national societies representing as many as 10,000 electroplating contractors to promote the energy, economic, and environmental benefits of the new technology.
In the future, third-party vendors will also be asked to participate in the development process. Interactions have already been initiated with Hoechst-Celanese, Chromato-Chem, Biorecovery, Kinetico, Inc., BDM, and Reilly Chemical as possible producers of materials or suppliers of commercial materials for use in the recovery systems. Researchers estimate that by 2010, production and use of the technology will make a significant positive impact on energy use and the environment, as well as promote economic growth. An estimated 1000 new jobs associated with the development of this technology will also be created by 2010.
For More Information:
Industrial Waste Program
EE-222
Office of Industrial Technologies
U.S. Department of Energy
1000 Independence Ave., SW
Washington, DC 20585
(202) 586-0198
Last Updated: February 13, 1996