Alkaline Noncyanide Zinc Plating and Reuse of Recovered Chemicals

PACIFIC NW POLLUTION PREVENTION RESEARCH CENTER
POLLUTION PREVENTION RESEARCH PROJECTS DATABASE

Project Title: Alkaline Noncyanide Zinc Plating and Reuse of Recovered Chemicals

Date Last Updated: 5/96

Project Summary: This project evaluated the feasibility of using an innovative, closed-loop rinsewater treatment system to precipitate plating chemicals for recovery and reuse and to produce purified water for recirculation to the rinsing tanks and sprayers. The goal of this study was to achieve zero discharge of the wastewater and total recycle of the recovered precipitate, thereby reducing the amount and toxicity of the waste from a zinc plating system. The zinc cyanide (CN) plating line was converted to one that uses an alkaline, noncyanide (ANC) zinc plating bath. A recovery/recycle (R/R) unit was then designed, installed, and tested to determine how completely the project goals were being met.

The R/R system did have some operating problems, but it proved to be highly efficient and economically advantageous to the plating operation. It had been in operation for over three years at the time the final report was written. Plating thickness was slightly less with the ANC bath, but ANC parts still met standards for thickness and corrosion protection. The change to ANC plating resulted in significant reduction of health and environmental risk, due to eliminating cyanide from the process.

Although reduced risks may be sufficient to justify the change from CN to ANC, the economic benefits derived were significant. Switching from a CN to an ANC process required a $36,000 capital investment and had a calculated payback period of 3 years. Using a R/R unit in addition to the process change required a $88,000 capital investment, with a payback period of 1.5 years.

Project Keywords: metal plating, zinc, cyanide, reuse, recycling

Organization Performing Research: Illinois Department of Energy and Natural Resources, Hazardous Waste Research and Information Center

Primary Research Contact: See funder contact

Date Research Started/Completed: 1993

Publications Based on Research: "Alkaline Noncyanide Zinc Plating and Reuse of Recovered Chemicals" by Jacqueline M. Peden, EPA/600/R-94/148.
Full report and project summary available through either:
* CERI Publications Unit, US EPA
26 W. Martin Luther King Drive
Cincinnati, OH, 45268
(513) 569-7582
or
* National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650

Approximate Project Budget: not reported,

Primary Project Funder: US EPA

Funder Contact:
Paul Randall
US Environmental Protection Agency
National Risk Management Research Lab
26 West Martin Luther King Dr., MS 466
Cincinnati, Ohio 45268
phone: (513) 569-7673
fax: (513) 569-7677
e-mail: randall.paul@epamail.epa.gov