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Regulations driving foundries to minimize and treat wastes.

Regulations Driving Foundries to Minimize and Treat Wastes

The second annual Environmental Affairs Conference, sponsored by the American Foundrymen's Society (AFS), was held Aug 23-24, 1989 in Milwaukee, WI, with more than 270 people in attendance. The Conference focus was on recycling, treatment and minimization of foundry wastes, steps that have become necessary because of today's increasingly stringent regulations and dwindling landfill capacity.

In his keynote address, Gary Mosher, AFS director of environmental affairs, spoke about the increasing public awareness of environmental hazards. He noted that along with this increased awareness has come a widespread fear of chemical exposure. This fear has, in turn, caused public servants to establish stricter environmental regulations, said Mosher.

Environmental Regulations

A good understanding of foundry wastes and the regulations concerning them simplifies compliance with environmental standards, said Bruce Paltenghi, an attorney with Gordon, DeFragra, Watrous & Pezzaglia. Foundries should know exactly what wastes they produce, and these wastes should be segregated. This segregation can help a foundry avoid uncertainty about which rules apply.

When reviewing regulations, Paltenghi added, particular attention should be paid to regulation "preambles" because they contain both a brief overview of the rules plus considerable background information.

Environmental regulation has changed considerably in scope, means of enforcement and level of magnitude, according to Richard Carlson, a consultant with Carlson, Knight & Kudrna. He noted that environmental control has gone from a local concern to a national issue; thus, federal regulations are now in place where previously only local laws existed.

Worker and community right-to-know laws force industry to periodically release information regarding its waste generation and disposal, Carlson continued. These laws give the public more information, resulting in increased pressure on firms to meet environmental standards. This increased pressure serves as an adjunct to local, state and federal environmental law enforcement.

In addition to changes in scope and enforcement methods, Carlson noted that the regulatory focus has shifted from readily observable pollution problems to parts per million exposure. He concluded by observing that the public now sees environmental protection as a moral issue and pollution as a sin.

Impact by Segment

Though challenges to reduce and treat wastes are impacting various areas of the industry in different ways, speakers representing the iron, steel, investment, brass and aluminum segments all urged extensive waste testing. Such testing allows a foundry to characterize its wastes and then determine which regulations are applicable.

Spent core and molding sands are by far the largest percentage of iron foundries' waste, according to Ralph Grotelueschen, Deere & Co. These large quantities of sand requiring disposal are responsible for higher landfill charges and, in some areas, dumping restrictions.

Grotelueschen said that beneficial reuse of foundry sands may help ease the future disposal problems faced by iron foundries but one obstacle to sand reuse must be overcome. That is its co-mingling with melt department waste, such as electric arc furnace dust which is considered a hazardous waste. "If co-mingling is avoided, it is possible to reuse the sand in other applications. Waste sand has value," he declared.

"In steel foundries," pointed out Jeff Stoflet, Atlas Foundry & Machine, "heavy metal contamination of contact cooling water from quench tanks may cause wastewater disposal problems." He then went on to describe what Atlas has done to overcome this problem.

William Dybvad, Duriron Co, reported that used slurry disposal was a problem until the foundry switched from an ethyl silicate-base to a colloidal silica-based slurry. The ethyl silicate material emits volatile organic compounds to the environment, but the colloidal silica-base material does not.

Ford Meter Box, a brass and bronze foundry, faced the higher landfill costs and increased liabilities associated with hazardous waste disposal when its waste sand was found hazardous (EP-toxic) due to lead contamination. According to John Flesher, the company began using iron dust to treat the sand and render it non-EP-toxic. The company also constructed a solid waste landfill on its own property for the safe disposal of this material.

At Stahl Specialty, an aluminum permanent mold foundry, [SO.sub.2] core process emissions require scrubbing. The scrubber water is treated before it is discharged. In addition to describing scrubber water treatment, Stahl's Jerry Call discussed selling dross to reclaimers. Call said it is important to follow up with the reclaimer after the sale. "Find out what they do with the dross waste after they reclaim it--you could become liable for what happens to it," he said.

Waste Minimization

Waste minimization through source reduction and recycling is an important means of pollution control. Harry Freeman, EPA's Office of Research & Development, discussed future regulatory developments in waste minimization and gave some short-term suggestions.

Freeman said that although the EPA is looking for and getting industry cooperation in waste minimization, it has not established set waste minimization levels. He does not believe the EPA would establish such set levels but firms are, nonetheless, required to have some type of waste minimization program. This lack of set EPA standards gives foundries great latitude in designing waste minimization programs, Freeman noted.

Charles Ruud, American Steel Foundries (ASF), and Anita Ryan, St. Paul Brass & Aluminum, discussed waste minimization in their foundries. Ruud reported some equipment modification, maintenance schedule alterations and material substitutions used at ASF to minimize waste. As an example, Ruud mentioned the introduction of watercooled panels in arc furnaces, which can reduce refractory wear and attendant waste disposal problems.

Ryan noted that many foundries either ignore waste minimization or put all their "eggs into one basket" when dealing with it. She said foundries should work with regulatory agencies, keep up on other foundries' efforts in this area and look into alternatives to waste minimization, such as waste exchange. According to Ryan, foundries also should review each step of the foundry process, since small changes can sometimes greatly reduce waste output.

Sand Reclamation

There are limitations to waste reuse and recycling, according to Dieter Leidel, Tanoak Enterprises, Inc. "There must be a match of supply and demand of the material under consideration. In case of excess supply, we are still left with a waste stream which has to go some place.

"And no matter where the `waste' will go," Leidel added, "we must apply some form of quality assurance." Untreated waste sand, consisting of small and large lumps with residual binder, tramp metal and dust, most likely would be unacceptable for reuse, he believes.

For these reasons, some form of source separation or reclamation of waste sands for reuse in the foundry is likely to interest metalcasters, he explained. Leidel discussed considerations in employing the dry attrition and thermal calcination methods to produce reusable sands. However, successful reclamation requires consideration not only of the usability of the reclaimed sand but also of the waste streams generated during reclamation, he stated including solid waste, gaseous emissions and waste cooling water.

Similarly, David Silsby, GMD Engineered Systems, in describing a thermal reclamation system, stressed the need to integrate the sand reclamation system with a complete waste handling system capable of treating exhaust gases and particulate emissions.

Chicago Faucet Co, a green sand foundry pouring a copper-base leaded alloy, employs a reclamation system that reclaims sand and recovers alloy for remelting. In describing this system, Chuck Davis said also that zinc-bearing baghouse dust is then sold to an outside metals recovery firm. The system has reduced the foundry's landfill volume by 87%. Metals recovery also has significantly improved the company's profitability.

Blackhawk Foundry is successfully selling its waste sand to a local Portland cement company, which uses it as a raw material in cement making, reported Blackhawk's James Grafton, Jr. He stated that while Portland cement companies around the country can use most foundry sands, this example of waste becoming a raw material in another process is not applicable to all foundry sands.

Heinz Beutner, Interel Corp, introduced a new emissions control process for volatile organic compounds (VOCs) produced during shell process molding. Beutner said the bio-catalytic process also can neutralize phenol formaldehyde and benzene emissions from hotbox processes and [SO.sub.2] and amine emissions from coldbox processes.

A scrubber with recirculating water carries the organic compounds to a reactor filled with carbon, oxygen and bacteria. The bacteria break the compounds down to [CO.sub.2] and water. Beutner reported that approximately 10% of the organics remain as solids and are accumulated as a low-toxicity sludge.

Working with Regulators

Industry and regulation makers have often had a confrontational relationship but this relationship is now becoming more cooperative. Deere & Co's Grotelueschen described how the American Cast Metals Association has worked with regulatory and legislative bodies to create beneficial reuse programs for foundry wastes. He pointed out several examples on the state level, including a Wisconsin highway project that incorporated used foundry sand in overpass construction.

William Child, Illinois State EPA, described some special programs enacted in the state to aid in waste disposal and treatment. Among these is the Illinois waste exchange, a program run by the state Department of Commerce, which brings together at no charge waste producers and firms that can use these wastes as raw materials.

The Toxic Pollution Prevention Program is a new Illinois program that grants two year experimental permits for new pollution control technology. Child said a firm must demonstrate only that the new process will be no worse than the old one and that it offers potential improvements.

Metals Reclamation/Stabilization

Processes developed to recycle electric arc furnace (EAF) dust, an EPA hazardous waste, were described by several speakers. These include a direct reduction process for treating zinc-bearing EAF dust which was discussed by Harsh Deb, IIT Research Institute; two technologies involving the reduction of carbon at elevated temperatures, one utilizing an electric plasma torch, the other a coal-based flame reactor, both described by Dr. John Svoboda, The Center for Metals Production, an R&D program funded by the Electric Power Research Institute; and a process involving sulfuric acid leaching followed by zinc electrowinning from the leach solutions, described by John Hanna, Mineral Resources Institute, Univ of Alabama.

Lead-toxic brass foundry sand is another material of concern. Much research has focused on stabilization of the lead to prevent its leaching, but Thomas E. Weyand, Pittsburgh Mineral & Environmental Technologies, reported on a process aimed at removal of heavy metals from the sand. Lead-bearing brass flakes are removed by magnetic separation; then, mineral acid leaching removes heavy metal contaminants from the brass fines. Nontoxic sand and recovered copper alloy are the results.

Lead-toxic baghouse and cleaning room dust was successfully marketed through a consulting service after a smelter could no longer accept the material, reported Henny Schoeller, St. Paul Brass & Aluminum. But, marketing metal-bearing hazardous waste as a feedstock or source of recoverable material is possible only if the material is a characteristic process waste or by-product, added Dr. Joe Schiller, Environmental Management Services. Examples are foundry baghouse dust, sand or sludge to be reclaimed for Cu, Zn, Ni and Cr.

PHOTO : How the waste challenge affects the different industry segments was discussed by (l-r): R.

PHOTO : Grotelueschen, J. Stoflet, W. Dybvad, J. Flesher and J. Call.
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Author:Donovan, Ben
Publication:Modern Casting
Date:Oct 1, 1989
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