NON-CYANIDE SILVER PLATING
|Overview:||Non-cyanide silver plating
deposits a silver coating to production parts by dipping the parts in a bath solution, and rinsing.
Using a non-cyanide plating process reduces the volume of hazardous waste generated and the
associated disposal costs, and exposure of personnel to hazardous materials and wastes.
Until recently, the majority of silver plating of production parts has been accomplished using cyanide-based processes. The disadvantages of cyanide-based plating are that cyanides are hazardous to personnel, require frequent bath solution change-outs due to limited bath life, and the generation of rinse streams containing high concentrations of metals and cyanides. The rinse water generated requires pre-treatment to remove the cyanides and metals at the Industrial Wastewater Treatment Plant before the water can be released to the Public Owned Treatment Works (POTW). The treatment process at the treatment plant requires the use of toxic chemicals such as sulfuric acid, caustic, chlorine, and other hazardous materials.
Chemicals used in cyanide-based silver processes
are toxic to humans and are strictly regulated by local, state, and federal agencies.
Using a non-cyanide process reduces
the volume of hazardous waste and decreases the amount of cyanide at the facility.
The reduction of hazardous waste helps facilities meet the requirements of waste reduction
under RCRA, 40 CFR 262, Appendix. It may also help facilities reduce their generator
status and lessen the amount of regulations (i.e., recordkeeping, reporting, inspections,
transportation, accumulation time, emergency prevention and preparedness, emergency response)
they are required to comply with under RCRA, 40 CFR 262. In addition, this technology allows
facilities to eliminate cyanide bath solutions, so there is less chance that the facility
would exceed the reporting thresholds for cyanide under SARA Title III
(40 CFR 300, 355, 370, and 372; and EO 12856). Both process types may require an industrial
wastewater discharge permit (local issue).
The compliance benefits listed here should be used as general guidelines and should not be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g., the amount of workload involved.
The plating process can only be applied to metallic substrates.
|Safety and Health:||
Caution must be exercised with the equipment. Proper personal protective
equipment must be worn and other safety practices must be employed.
Consult your local industrial health specialist, your local health and safety personnel, and the appropriate MSDS prior to implementing this technology.
|Economic Analysis:||The National Defense Center
for Environmental Excellence (NDCEE), operated by Concurrent Technologies Corporation (CTC),
was tasked by the Department of Defense to investigate the technical viability of the non-cyanide
silver process. No detailed economic analysis has been performed; however, the non-cyanide silver process can be implemented using existing tanks, heaters, and ventilation systems. The only cost variable will be for the initial make up for the process bath.
|Approving Authority:||Appropriate authority for making process
changes should always be sought and obtained prior to procuring or implementing any of the
technologies identified herein.
|Points of Contact:||For more information
This is not meant to be a complete list, as there may be other suppliers of this type of equipment.
|Sources:||Concurrent Technologies Corporation. Non-Cyanide Silver Plating: Test Report. October 7, 1998.|