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The US EPA has conducted various research projects to support the metal finishing industry. Many of the projects were an outgrowth of EPA's Common Sense Initiative (CSI). CSI is a cooperative effort of government, industry, environmental groups, and other stakeholders to find "cleaner, cheaper, smarter" approaches to environmental management in industrial sectors. The following projects have been conducted over the past five years:

Powder Coating

Abstract: Non-Hazardous replacement of Chromate Conversion Coating for Aluminum substrates and Zinc Phosphating for Steel Substrates when Powder Coating. This report describes a study performed to measure the effectiveness of Picklex®, a surface finishing liquid bath product with environmental benefits, as an alternative to conventional commercial metal surface pretreatments and conversion coats in an industrial setting. EPA conducted a broad-application laboratory evaluation of Picklex® during Phase I. Then in this Phase II study, EPA conducted a focused field test with Picklex® for powder coating applications on aluminum and steel. Chromate Conversion coatings were replaced for aluminum substrates and zinc phosphate coating was replaced for for steel substrates. Aluminum die cast alloy and malleable iron casting components were also processed. The coatings were evaluated by a matrix of tests including adhesion, bend adhesion, impact adhesion, hardness, and corrosion resistance. This field study was conducted in an actual power coating shop was conducted to validate the lab results. An engineering assessment indicated that Picklex® can have cost advantages as well.

Non-Hazardous replacement of Chromate Conversion Coating for Aluminum substrates and Zinc Phosphating for Steel Substrates when Powder Coating. (PDF, 253 Kb, 24 pp)

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Evaluation of Biodegradable Degreaser

This technical and economic assessment evaluated the effectiveness of a biodegradable degreaser called Graff-Off, which has a coconut oil-base. In immersion cleaning and rinse tests, Graff-Off was compared to a conventional chlorinated solvent (1,1,1 trichloroethane, TCA) and to an alkaline cleaner (Aeroclean DN-30). Both alternatives were found to be technically superior to TCA. Both alternative degreasers had lower cleaner costs and allowed a greater surface area to be cleaned per unit volume of degreaser. Estimated savings were significant and capital requirements were modest. An economic assessment indicated that Graff-Off and the DN-30 alkaline cleaner were extremely attractive alternatives to TCA, as gauged by net present value, internal rate of return, and payback period.

Laboratory Scale Evaluation of Hydra-Tone Graff-OffTM Coconut Oil-Based Degreaser (PDF, 666 Kb, 67 pp)

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Non-Polluting Method for Metal Surface Finishing Pretreatment

Picklex®, a proprietary formulation, is an alternative to conventional metal surface pretreatments. Its developers claim that it does not produce waste or lower production rates, and it will maintain performance compared to conventional processes. A laboratory program was designed to compare Picklex® with conventional processes in common, large scale, pollution surface finishing operations. This was done using steel and aluminum panels, measuring product coating properties, process operability, and costs. Over twenty surface finishing combinations were tested to evaluate such qualities as finish adhesion, bending, impact, hardness, and corrosion resistance. Results indicate that Picklex®-pretreated panels performed as well as panels that were conventionally pretreated, and with a simpler non-hazardous process. Picklex® is particularly acceptable for powder coated steel or aluminum, but may not be for certain metal plates. A use rate of 5,400 ft2/gal was estimated. Picklex® did not generate by-product waste solids, was effective at room temperature, used short processing times, and was easy to use. An engineering assessment indicated that Picklex® can have cost advantages as well. These results suggest that Picklex® is a promising alternative in some metal surface pretreatments, such as chromate conversion coating of aluminum. This article was published in Clean Products and Processes, January 2001 Volume 2- Issue 4-February 2001. Exit EPA "Picklex as a non-polluting metal surface finishing pretreatment and pretreatment/conversion coating" David Ferguson, B. Hindin, A. Chen, B. Monzyk A second article which describes actual field testing of Picklex is published in the proceedings of the AESF/EPA Conference for Environmental Excellence, January 29-31, 2001. The article is entitled "Non-Polluting Metal Surface Finishing Pretreatment and Pretreatment/conversion Coating" David Ferguson, Bruce Monzyk. Link Exit EPA

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Pollution Prevention and Control Technologies for Air Emissions for Hexavalent Chromium Electroplating

The purpose of these projects was to help hard chrome metal platers to reduce the emissions from plating tanks to comply with EPA's Chromium Emissions MACT Standard in a cost-effective manner. The publications evaluate the effectiveness of various control technologies as well the pollution prevention technique of using mist suppressants in the chromium bath. The publications are as follows:

"Use of Fume Suppressants in Hard Chromium Baths-Quality Testing", David Ferguson, Matthew Zellen, Dawn Brennan, Janette Lutz. Plating and Surface Finishing Feb/00, Vol 87, No. 2, pp 67-72

"Use of Fume Suppressants in Hard Chromium Baths-Emission Testing", David Ferguson, Briana Sprague, Dawn Brennan, Janette Lutz. Plating and Surface Finishing Jan/00, Vol 87, No.1, pp 72-74

EPA Capsule Report "Hard Chrome Fume Suppressants and Control Technologies"
EPA/625/R-98/002 December, 1998

"Cost Effective Control of Hexavalent Chromium Air Emissions From Functional Chromium Electroplating" David Ferguson and Roger Wilmoth. Environmental Health & Safety Solutions" Jan/00, Vol1, No.3, pp10-19

"Mist Suppressants in Hard Chromium Electroplating", David Ferguson, Plating and Surface Finishing, June 1998 Volume 85, No. 6, pp76-93

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Managing Cyanide in Metal Finishing

Both the government and the private sector are exploring the uses of Cyanide in metal finishing. Environmental, health and safety requirements and competitive pressures have forced metal finishers to adopt better process management practices. Advances in operating practices, process control, chemical recovery and treatment make it possible to use cyanide responsibly without creating additional risk for workers or the public. To manage cyanide efficiently, one must understand its toxicity and tightly control exposure. In addition, the chemistry of the cyanide system must also be controlled so that little is lost from the system. In this context, the system encompasses the plating process tanks, rinse tanks, recovery systems, waste treatment and air emission control devices. Together these elements form a facility that can effectively use cyanide, yet protects the workers from significant exposure and minimizes environmental impact from water, solid waste and air emissions.

Many inside and outside the industry assume non-cyanide processes to be environmentally and occupationally safer than cyanide processes. The issues are much more complex than that.
This report covers various aspects of cyanide's chemistry, use, toxicity, problems and control.

EPA Capsule Report Managing Cyanide in Metal Finishing
EPA/625/R-99/009 December 2000

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National Metal Finishing Research & Development Plan

This document is an update to the National Metal Finishing Environmental R&D Plan (EPA/600/R-97/095), dated September 1997. The 1997 Plan and Update are available on the National Metal Finishing Resource Center's web site, www.nmfrc.org Exit EPA The primary purpose in preparing an update to the 1997 Plan is to incorporate new information and/or changes that affect the environmental issues facing the metal finishing community. Since the 1997 Plan, there have been changes in regulations relating to the metal finishing industry and changes in technology that have resulted from R&D projects in the past few years. New technology needs have surfaced. There are global and national changes in economies and product demands, and greater concerns for the environment and human health. The 1997 Plan was designed to continuously evolve with the metal finishing industry. This Update incorporates such changes.

"National Metal Finishing R & D Plan - An Update" EPA Report 600/R-00/035 Approved for Publication March/2000. (PDF, 95 Kb, 33 pp)

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Bath Life Extension for Aqueous Cleaners

The effectiveness of a zirconium dioxide (ZrO2) membrane filter was evaluated for recycling a nonionic aqueous metal cleaning bath under real-world conditions. The pilot-scale study consisted of four 7- to 16-day filtration runs, each processed a portion of the cleaning bath during immersion cleaning of aircraft engine and motor parts. The results indicated that the filter was effective in removing contaminants such as oil and grease and suspended solids from the process solution, thus extending the life-span of the bath up to 3 times. The process bath, however, had to be replenished with surfactant additives to compensate for the surfactants removed by the filter. The fouled membrane could be effectively cleaned with its permeability fully restored for reuse.

"Using Ceramic Membranes to Recycle Two Nonionic Alkaline Metal-Cleaning Solutions", Abraham S.C. Chen, Nicholas Stencel, David Ferguson, Albert Pollack. Journal of Membrane Science. December 1999, 162 pp 210-234

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Electroless Nickel

Abstract : The waste treatment and rejuvenation of spent electroless nickel baths has attracted a considerable amount of interest from electroplating shops, electroless nickel suppliers, universities and regulatory agencies due to the finite life of the baths and the associated waste that the process generates. It is generally accepted that the recycling of electroless nickel solutions is one of the most important challenges facing the electroless nickel plating industry today. This review presents an overview of the existing and emerging technologies for extending the life of electroless nickel baths. The electroless nickel bath regenerative technologies are appraised from the standpoint of removal of harmful bath components, loss of valuable bath components, cost-effectiveness, secondary waste generation and ease of implementation. The review draws upon an array of academic papers, industrial/company reports, conference proceedings and patents in order to allow the reader to evaluate and compare the different technologies and options for extending the life of electroless nickel-plating solutions.

This article was published in Clean Products and Processes, January 2001 Volume 2- Issue 4-February 2001. Exit EPA "Current and emerging technologies for extending the lifetime of electroless nickel plating baths" Paul T. Bolger, David C. SzIag
Link.

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Electrolytic Nickel

Closed-Loop Treatment of Electrolytic Nickel Rinse Water by Point-Of-Use Ion Exchange: A Case Study.
Dave Szlag, Joe Leonhardt , Albert Foster, Mike Gossland, Paul Bolger.

Many recent pilot tests have demonstrated the benefits and cost effectiveness of point-of-use treatment technologies as opposed to centralized wastewater treatment for all sizes of plating facilities. A 9-month case study at a small plating facility in Cincinnati, 0hio utilizing point of-use ion exchange is described in this report. The principal constituents were tracked through the rinsing process for the electrolytic nickel lines. These results were used to develop simple mathematical tools that allow one to estimate the effectiveness of an existing rinsing station / ion exchange configuration and explore new options. We describe how these tools can be used to identify relationships between workload, rinsing station design, ion exchange system design, and temporal fluctuations in the mass loads handled by the point-of-use ion exchange system. This facility has recently switched from using an ion exchange service to a totally on-site system. The effectiveness, operational experience and costs associated with the each ion exchange approach are also presented.

This article is published in the proceedings of the AESF/EPA Conference for Environmental Excellence, January 29-31, 2001. The article is entitled "Closed-Loop Treatment of Electrolytic Nickel Rinse Water by Point-Of-Use Ion Exchange: A Case Study" Dave Szlag, Joe Leonhardt , Albert Foster, Mike Gossland, Paul Bolger.

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Approaching Zero Discharge in Surface Finishing

In its broadest sense, "zero discharge" implies no discharge of pollutants to any media. More commonly, zero discharge focuses on zero wastewater discharge. This report presents information and strategies for "approaching zero discharge" (AZD) of concentrated process fluids and wastewater in surface finishing. The report presents key techniques and technologies that support AZD initiatives. A general approach for pursuing and implementing AZD actions is described. It also discusses strategies and planning related to systems engineering and overall integration of AZD alternatives into manufacturing operations.
(Report Coming Soon)

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Other Links for Metal Finishing Information

Metal Finishing Research Contact:

David Ferguson
Phone: 513-569-7518
FAX: 513-569-7471
E-Mail: ferguson.david@epa.gov

Office of Research & Development | National Risk Management Research Laboratory

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