Cadmium and Chromium Recovery from Electroplating Rinsewaters

PACIFIC NW POLLUTION PREVENTION RESEARCH CENTER
POLLUTION PREVENTION RESEARCH PROJECTS DATABASE

Project Title: Cadmium and Chromium Recovery from Electroplating Rinsewaters

Date Last Updated: 5/96

Project Summary: The objectives of this study were to evaluate: 1) the effectiveness of the ion exchange unit in cleaning the rinsewater for reuse in the rinse tanks, 2) the pollution prevention potential of this technology, and 3) the cost of ion exchange versus the cost of the former practice (disposal). The test included collecting three samples each of the rinsewater, before and after passing through the ion exchange system. These samples were analyzed in the laboratory to evaluate the removal of contaminants.

The results of the laboratory analysis of the cadmium rinsewater samples showed that most of the cadmium and cyanide were removed by ion exchange - in some cases, to below detection levels. The pH of the rinsewater remained steady at alkaline levels throughout the testing. Prior to ion exchange, approximately 69 lbs. of cadmium and 281 lbs. of cyanide were discharged annually. Now, because most of the cadmium can be recovered and reused, this pollutant is virtually eliminated from the wate stream. On the chromium line, without ion exchange, approximately 80 lbs. of chromium is discharged annually. With ion exchange, most of the chromium will be captured on the resin, which will be regenerated with NaOH. However, further testing is needed to determine the feasibility of the chromic acid recovery process.

For the cadmium ion exchange system, the return on the investment (with cost of capital equal to 15%) was less than one year. For the chromium process, the return on investment (with capital at 15%) was over five years. Because chromic acid recovery from the regenerant is yet to be established, no recycled chromium value is assumed. These calculations take into account taxes, depreciation, inflation, etc. and are based on the worksheets provided in the Facility Pollution Prevention Guide (EPA 600/R-92/088). The costs include engineering and installation as well as increased overhead.

Project Keywords: ion exchange, rinsewater, electroplating, rinsewater, cadmium, chromium, metal cleaning

Organization Performing Research: Connecticut Hazardous Waste Management Service; Battelle, Columbus Labs

Primary Research Contact: not reported

Date Research Started/Completed: 1993

Publications Based on Research: "Cadmium and Chromium Recovery from Electroplating Rinsewaters" by Arun Gavaskar, et al., EPA/600/R-94/050.
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