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FULL OF SCRAP A big stink and bigger charge over renegade salt cake

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Some of the hardest-to-get-rid-of business headaches come from things that go wrong only occasionally.

Take the leftovers from making secondary aluminum from scrap. The dross that forms at the surface has enough aluminum to be worth its own recycling process, often done by a different company. Eventually, one is left with a residue called salt cake, ideally with minimal aluminum but containing soluble salts from the flux and nonmetallic oxides. That typically goes to a landfill.

Paul Schaffer
Paul Schaffer
At a reasonably modern landfill, most of the time the stuff sits dormant. But when Murphy's Law kicks in, the result can be what Will Flower of Republic Services Inc. refers to as his company's "$22-million headache."

Approximately 1 million short tons of aluminum dross residue went to the Countywide Recycling & Disposal facility in East Sparta, Ohio, starting in 1991, much of it when Waste Management Inc. was the owner of the 818-acre site. Waste Management, sold it to third-ranked Republic, based in Fort Lauderdale, Fla., in 1999. Two years later, Republic stopped accepting aluminum dross waste at Countywide, and last year it banned all aluminum wastes at Countywide and extended its dross waste ban to all Republic facilities in 21 states.

But the accumulated problem at Countrywide didn't just fade away. "We incurred a $22-million charge in the first quarter of 2007 to fix the site and comply with orders from the Ohio Environmental Protection Agency," Flowers told AMM. "Damage to our reputation and image in the community is enormous and has negatively impacted our business."

The overt problem wasn't a health risk, but a recurrent and pervasive odor. The stuff is fine when dry, but contact with water can lead to a wide variety of gaseous emissions, some of which burn underground.

"If a landfill has accepted aluminum production waste, it is important to watch for indications of a subsurface fire," Ohio's EPA said in a July advisory. According to the agency, aluminum production wastes exposed to water can react and emit toxic, flammable and potentially explosive gases, including ammonia, methane, hydrogen and acetylene.

"I suspect that salt cake will eventually be seen as hazardous waste due to problems with leachate (spreading liquid) and gas generation," said Mark Schlesinger, a professor of metallurgical engineering at University of Missouri's Rolla campus who recently wrote a book called Aluminum Recycling.

A German company with an offshoot in Becancur, Quebec, says it can turn secondary aluminum residues into marketable substances with zero landfill. Michael Romberg, president and chief executive officer of Agor AG, told AMM recently that the Becancur facility did test runs this year for three U.S. aluminum smelting companies.

"Every salt slag is a little bit different. We processed the salt slags and we have the basis for a plant layout. We are prepared to build a plant in the United States. When they are ready, we are ready," Romberg said. One potential site would serve southern Indiana, Kentucky and Tennessee, he said. Ohio and the Chicago area are also being considered.

But there is a question mark over whether potential customers will find that option financially attractive. "Economy of scale will be important in salt cake processing," Schlesinger said. "No single aluminum recycling plant is likely to generate enough of it to justify its own processing facility."

Agor's Becancur facility was largely closed from late 2005 to early 2007, partly to adjust the technology and partly to develop reliable ties with buyers of the output. The plant, Recyclage d'Aluminium Quebec Inc., started out recycling aluminum from the primary production dross of Alcoa Inc. It became German-owned in 2001; the buyer became Agor in 2003.

Romberg said Agor's process has four outputs, two of them being recovered aluminum and a reusable version of the salt flux inserted at smelters. The hard part is finding a use for the low-value leftovers. For ammonium sulfate, there is a fertilizer application. The final component, which Agor describes as a fine-grained mineral substance with a high aluminum oxide content, is marketed as an input for cement and for making the mineral wool used as construction insulation.

Meanwhile, landfill owner Republic Services asked a consultant to test some fire suppressant chemicals on samples from the smoldering Ohio landfill. None worked. "This unexpected result is not readily explained," the adviser reported.

A December map of the landfill's underground temperatures shows readings up to 195 degrees Fahrenheit.


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