NON-CYANIDE NICKEL STRIPPERS
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| Overview: | Non-cyanide based metal stripping removes metal based coatings from production parts by dipping the parts in a bath solution, and rinsing.
Using a non-cyanide based metal stripping 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 stripping of metal coatings from production parts has been accomplished using cyanide based processes. Parts that require rework often need to remove previously applied metal coatings. Cyanide based processes are capable of removing many different metal coatings such as nickel (Ni), silver (Ag), copper (Cu), zinc (Zn), gold (Au), and other precious metals without damaging the surface of the part itself. The disadvantages of cyanide-based stripping are that cyanides are hazardous to personnel, require frequent bath solution change-outs due to a limited bath life, and generate 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 (IWTP) before the water can be released to the Public Owned Treatment Works (POTW). The treatment process at the IWTP requires the use of toxic chemicals such as sulfuric acid, caustic, chlorine, and other hazardous materials. There are a number of commercially available non-cyanide metal stripping processes that can be implemented to replace cyanide-based metal stripping processes. These alternative metal strippers use amines, aromatic nitro compounds, protein based and/or other oxidizing chemicals. The following process parameters must be examined for any alternative before implementation can occur: stripping rate, corrosion potential of the base metal, reaction with maskants, bath stability, and treatability of rinse waters or spent process bath material.
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| Compliance Benefit: |
Non-cyanide based metal stripping removes metal based
coatings from production parts by dipping the parts in a bath solution,
and rinsing. Using a non-cyanide based metal stripping process, instead
of a more traditional cyanide based bath, reduces the volume of hazardous
waste
(since non-cyanide based baths can be used longer) 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, and 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 (cyanide has an RQ) so there is less of a chance that the facility
would meet any of the reporting thresholds
for cyanide under SARA Title III (40 CFR 300, 355, 370, and 372; and EO 12856). Both processes may require an industrial wastewater
discharge permit (local issue).
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| Materials Compatibility: |
Due to the variability of non-cyanide based bath solutions, it is highly recommended that the activity reference the vendors data for specific incompatibilities between bath solution and other materials/chemicals.
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| Safety and Health: |
Many components of a non-cyanide metal stripper are biodegradable
and present minimal safety risks. However; several components do present
splash, heat and vapor hazards. Bath solution temperatures range from
room temperature to 1800 degrees F, appropriate precautions shall be observed.
Nickel compounds can be skin irritants. Proper personnel protective equipment
should be used.
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| Benefits: |
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| Disadvantages: |
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| Economic Analysis: | Non-cyanide nickel strippers 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. This will be offset
by the fact that non-cyanide baths have a bath life two to three times that of cyanide based
baths. Also, eliminating the cost (chemicals and labor) for
the treatment of cyanide contaminated rinse waters will yield greater savings.
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| NSN/MSDS: |
*There are multiple MSDSs for most NSNs. The MSDS (if shown above) is only meant to serve as an example. To return from the MSDS, click the Back arrow on the Tool Bar.
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| 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.
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| Points of Contact: | For more information
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| Vendors: |
This is not meant to be a complete list, as there
may be other suppliers of this type of equipment.
Technic, Inc.
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| Sources: | None listed. |