AISI’s Symposium on Recycling and Resource Recovery

A Look at Tin- and Zinc-Coated Steels

Commercial and technical aspects involved in recycling coated steel products were examined at a recent American Iron and Steel Institute symposium.

Moderators Bill Heenan and Kurt Smalberg, chairman and president, respectively, of the Steel Can Recycling Institute (SCRI), opened the first day's session by reviewing recent gains in steel can recycling rates. According to Smalberg, the 1989 postconsumer steel can recycling rate was 21.6 percent. By 1995, he foresees a 66-percent rate.

Not all attendees shared that Optimistic forecast. Questions were raised throughout the symposium concerning the economic feasibility of steel can collection, as well as specific technical issues involving steel mill tolerances of certain alloying elements found in today's coated steels. Nevertheless, many attendees saw increased potential for capturing and consuming greater amounts of the approximately 3-5 million tons of tin-coated steel cans currently heading for our nation’s landfills each year.

Ban the Can?

Legislative aspects that could negatively affect all types of packaging, including cans, were discussed by SCRI’s Rebecca Linn. With packaging estimated to account for approximately one-third of the total municipal solid waste (MSW) generated each year, Linn observed that pressures are building to find long-term solutions to solid waste generation. The problem, however, is finding a balanced view given what she termed a "new recycling ethic" that has evolved over the past decade. Linn explained that as legislators cope with mandated national and state goals to reduce MSW volumes, a "ban the can" mentality is resulting, which is a real threat to the steel industry. Unless recycling rates improve, the "ban the can" mentality will prevail, she said. Not only are existing markets threatened, but as one Canadian steel mill executive remarked, recovered steel cans are being forced on mills at artificially high prices.

Is Curbside Collection the Way to Go?

Curbside collection as a means to lower MSW generation was discussed by John W. Snellen, Waste Management of North America, Inc., Oak Brook, Illinois. His company is believed to be the largest collector of curbside materials, with approximately 1.5 million households currently serviced. According to Snellen, approximately 10 million U.S. households now have some kind of curbside collection program in place. Most programs, he noted, include steel cans commingled with other containers.

Are curbside programs economical? According to Snellen, commingled curbside programs break even when MSW disposal costs are between $50 and $60 per ton. Looking closer at the economics of curbside collection programs, he said that steel cans contribute approximately 2 percent of the total revenue generated--far lower than that for aluminum cans or glass containers. Waste Management estimates that approximately 35 tons of steel are separated from every 1,000 tons of MSW generated. As for the amount of steel reclaimed by the company, in 1989 approximately 15 million pounds of steel in cans were recovered, compared with only 8 million pounds in 1988. This year, Snellen said, Waste Management expects to recover 20 million pounds of steel from cans.

Lucian C. Bielicki, Bi-Metal Corp., Ridgefield, Connecticut, took a negative view of curbside collection programs. He believes that when MSW is processed in a front-end separation system in conjunction with an established refuse-derived fuel or a mass-bum facility, steel cans ought to remain with the garbage-not be source separated. Bielicki described his processing plant in Suffolk, Virginia, which he said successfully recovers approximately 100 tons of cans per day. (The firm also operates a facility in Niagara Falls, New York.)

Although optimistic about steel can recycling, Bielicki captured the audience's attention by observing that for the steel can industry to be truly successful with recycling, it ought to develop a 100-percent-steel can, instead of using aluminum lids and steel bodies, as is currently done. In addition, he said, the tin content should be further reduced.

I Michael Coslov, Tube City Inc., Bala Cynwyd, Pennsylvania, also discussed curbside collection. In his view, without subsidies from municipalities, such programs "do not make economic sense."

Coslov reminded the audience that scrap is, first and foremost, a commodity with which profits are made or lost in turning over material, as opposed to manufacturing and marketing a value-added product. In order for scrap to move efficiently, he emphasized, the suppliers of scrap and the consuming steel mills must establish close relationships so they fully understand and appreciate the economics of using scrap as a raw material. "It's not technology that dictates scrap usage," he concluded, "it's economics. "

Steel Mills Reluctant to Push Up Tin Limits

Several papers were presented at the second day's session that covered technical aspects of handling and consuming tin in steel scrap. Richard Fruehan, Carnegie Mellon University, Pittsburgh, served as moderator. He cited significant energy savings from using scrap, but raised questions about scrap metal metallurgy: Is scrap detrimental to the melt? Are mill product specifications too restrictive?

Peter Koros, LTV Steel, examined tin in both cast products and steel ingots. Although available research data on tin over the past decades were termed by Koros "incomplete"--especially for cast products--his key point was that a melt shop's concern was not necessarily the absolute amounts of tin in steel, but the relative combination of all alloying elements in steel. For example, higher tin tolerances for cast products were possible, Koros said; but he warned steelmakers that they might be trading off metallurgical benefits of lower sulfur, copper, and nickel at the expense of higher melt capabilities.

According to Perry Van Rosendale of the USS division of USX, Pittsburgh, his company has been consuming cans since 1983. USS's basic oxygen furnace shop at the Gary Works plant melted 8,500 tons last year, while the company's two Chicago facilities consumed 15,000 tons. However, the can potential was considerably greater than the actual amounts being melted, noted Van Rosendale. He calculated that assuming 2,000 pounds of can per heat, a total of 36,000 tons of can scrap could be consumed annually at Gary Works.

At the same time, however, Van Rosendale conceded that residual tin units are a "problem element"--especially with mill product specifications calling for 0.02-percent maximum tin. On a more positive note, the use of bimetallic cans (85 percent iron, 15 percent aluminum) provides an added fuel source as a result of aluminum's exothermic reaction in the steelmaking charge.

The Timken Company, Canton, Ohio, also successfully uses steel cans in its electric arc furnace shop, according to Eric Walsky. He noted that the company first started using postconsumer incinerated can scrap in 1987. According to Walsky, over a six-month period involving 100 heats, the program was termed largely successful; but as scrap values increased for this particular type of feed, in Timken's view, the overall benefits did not justify the higher raw material costs. He said residual tin levels also increased and there was some concern that Timken's return scrap ultimately would be contaminated. (This fear was also expressed by Van Rosendale.) Walsky was generally positive about using incinerated material as a feed source, but he said he believes that this type of feed material will remain a very low-value item.

Tin and Zinc Recovery

Tin and zinc recovery also were highlighted during the symposium. Peter Koros, moderator of this session, provided a metallurgical perspective of the two alloying metals in terms of removing tin and zinc from steel. Koros noted concern over the increased usage of galvanized steel products and the effect of large amounts of zinc-containing flat-rolled products that ultimately will return for recycling in this decade and the next.

Detinning of steel was explored by Dick Schulte, AMG Resources Corporation, Pittsburgh. He looked at cans collected from commingled curbside collection programs, from front-end municipal solid waste separation systems, and from material recovered from incinerators. He viewed this last source as "least desirable" in terms of ash accumulation, low metallic yields, and "zero recovery of tin units." Schulte believes, however, that the future for can scrap recovery will be from front-end separation systems.

Stephen Basarab, Proler International Corp., Houston, also looked at tinplate scrap and detinning. According to Basarab, tin contained in tinplate scrap is approximately 6 to 6.5 pounds per gross ton of steel today, compared with 10 pounds in 1960 and 7.5 pounds in 1965. He further calculated that approximately 3.5 million tons of cans are going to landfills every year. His presentation included a detailed look at Proler's Houston facility, which has the capacity to continuously treat 180,000 tons of scrap annually.

Removing zinc units from galvanized steel was reviewed by William A. Morgan, Metal Recovery Industries, Inc., Hamilton, Ontario. The company is currently working with Argonne National Laboratory in developing a process to remove zinc before the coated material goes into a furnace. According to Morgan, the feed material is mostly prompt industrial scrap. The treatment uses a one-step process involving hot caustics and high currents to remove 98 percent of the zinc contained on hot-dipped, electrolytic, galvalume, or galvannealed steels. Morgan noted further that the process is an environmentally "closed system," is low in capital cost, and can use both densified and loose zinc-coated scrap. He expects that this dezincing process will be commercially proven and available by year end.

[SIDEBAR]

Garvey's Good News About Scrap

Robert A. Garvey, president of North Star Steel Company, Minneapolis, was the keynote speaker at AISI's symposium. The company currently operates eight electric furnaces at five facilities in the United States and is considered to be one of the largest purchasers and consumers of ferrous scrap.

Garvey noted at the outset that, with respect to scrap fundamentals, "the good news is that scrap quality and supply will exceed demand for the foreseeable future." As for residual elements found in scrap--of special concern to all melt shops--Garvey said that the issue is "somewhat overblown." However, he also recognized that elements such as copper, nickel, chromium, and tin "will require our attention in the 1990s and beyond."

Examining scrap's supply side further, Garvey cited extensive published research studies that point to rising obsolete scrap reserves. (North Star Steel has calculated a ferrous scrap reserve approaching 1 billion tons.) He said he does not think nonoxidizable residuals are a growing threat; in fact, he admitted to being hard pressed to detect a significant change in residual content among the most commonly recycled grades of scrap. Garvey stated that, in particular, copper, tin, and nickel found in purchased scrap could be controlled by maintaining rigid quality and processing standards. He called for scrap to be treated as a raw material, "instead of as junk."

Garvey also reviewed alternatives to scrap: direct reduced iron (DRI) and iron carbide. He said that despite the fact that DRI is being used in the United States, it is not likely to become a significant source of raw material in the country. Nor is DRI expected to threaten scrap use in Europe or Japan--regions he termed "scrap-rich."

A Look at Tin- and Zinc-Coated Steels

Commercial and technical aspects involved in recycling coated steel products were examined at a recent American Iron and Steel Institute symposium.

Moderators Bill Heenan and Kurt Smalberg, chairman and president, respectively, of the Steel Can Recycling Institute (SCRI), opened the first day's session by reviewing recent gains in steel can recycling rates. According to Smalberg, the 1989 postconsumer steel can recycling rate was 21.6 percent. By 1995, he foresees a 66-percent rate.

Not all attendees shared that Optimistic forecast. Questions were raised throughout the symposium concerning the economic feasibility of steel can collection, as well as specific technical issues involving steel mill tolerances of certain alloying elements found in today's coated steels. Nevertheless, many attendees saw increased potential for capturing and consuming greater amounts of the approximately 3-5 million tons of tin-coated steel cans currently heading for our nation’s landfills each year.

Ban the Can?

Legislative aspects that could negatively affect all types of packaging, including cans, were discussed by SCRI’s Rebecca Linn. With packaging estimated to account for approximately one-third of the total municipal solid waste (MSW) generated each year, Linn observed that pressures are building to find long-term solutions to solid waste generation. The problem, however, is finding a balanced view given what she termed a "new recycling ethic" that has evolved over the past decade. Linn explained that as legislators cope with mandated national and state goals to reduce MSW volumes, a "ban the can" mentality is resulting, which is a real threat to the steel industry. Unless recycling rates improve, the "ban the can" mentality will prevail, she said. Not only are existing markets threatened, but as one Canadian steel mill executive remarked, recovered steel cans are being forced on mills at artificially high prices.

Is Curbside Collection the Way to Go?

Curbside collection as a means to lower MSW generation was discussed by John W. Snellen, Waste Management of North America, Inc., Oak Brook, Illinois. His company is believed to be the largest collector of curbside materials, with approximately 1.5 million households currently serviced. According to Snellen, approximately 10 million U.S. households now have some kind of curbside collection program in place. Most programs, he noted, include steel cans commingled with other containers.

Are curbside programs economical? According to Snellen, commingled curbside programs break even when MSW disposal costs are between $50 and $60 per ton. Looking closer at the economics of curbside collection programs, he said that steel cans contribute approximately 2 percent of the total revenue generated--far lower than that for aluminum cans or glass containers. Waste Management estimates that approximately 35 tons of steel are separated from every 1,000 tons of MSW generated. As for the amount of steel reclaimed by the company, in 1989 approximately 15 million pounds of steel in cans were recovered, compared with only 8 million pounds in 1988. This year, Snellen said, Waste Management expects to recover 20 million pounds of steel from cans.

Lucian C. Bielicki, Bi-Metal Corp., Ridgefield, Connecticut, took a negative view of curbside collection programs. He believes that when MSW is processed in a front-end separation system in conjunction with an established refuse-derived fuel or a mass-bum facility, steel cans ought to remain with the garbage-not be source separated. Bielicki described his processing plant in Suffolk, Virginia, which he said successfully recovers approximately 100 tons of cans per day. (The firm also operates a facility in Niagara Falls, New York.)

Although optimistic about steel can recycling, Bielicki captured the audience's attention by observing that for the steel can industry to be truly successful with recycling, it ought to develop a 100-percent-steel can, instead of using aluminum lids and steel bodies, as is currently done. In addition, he said, the tin content should be further reduced.

I Michael Coslov, Tube City Inc., Bala Cynwyd, Pennsylvania, also discussed curbside collection. In his view, without subsidies from municipalities, such programs "do not make economic sense."

Coslov reminded the audience that scrap is, first and foremost, a commodity with which profits are made or lost in turning over material, as opposed to manufacturing and marketing a value-added product. In order for scrap to move efficiently, he emphasized, the suppliers of scrap and the consuming steel mills must establish close relationships so they fully understand and appreciate the economics of using scrap as a raw material. "It's not technology that dictates scrap usage," he concluded, "it's economics. "

Steel Mills Reluctant to Push Up Tin Limits

Several papers were presented at the second day's session that covered technical aspects of handling and consuming tin in steel scrap. Richard Fruehan, Carnegie Mellon University, Pittsburgh, served as moderator. He cited significant energy savings from using scrap, but raised questions about scrap metal metallurgy: Is scrap detrimental to the melt? Are mill product specifications too restrictive?

Peter Koros, LTV Steel, examined tin in both cast products and steel ingots. Although available research data on tin over the past decades were termed by Koros "incomplete"--especially for cast products--his key point was that a melt shop's concern was not necessarily the absolute amounts of tin in steel, but the relative combination of all alloying elements in steel. For example, higher tin tolerances for cast products were possible, Koros said; but he warned steelmakers that they might be trading off metallurgical benefits of lower sulfur, copper, and nickel at the expense of higher melt capabilities.

According to Perry Van Rosendale of the USS division of USX, Pittsburgh, his company has been consuming cans since 1983. USS's basic oxygen furnace shop at the Gary Works plant melted 8,500 tons last year, while the company's two Chicago facilities consumed 15,000 tons. However, the can potential was considerably greater than the actual amounts being melted, noted Van Rosendale. He calculated that assuming 2,000 pounds of can per heat, a total of 36,000 tons of can scrap could be consumed annually at Gary Works.

At the same time, however, Van Rosendale conceded that residual tin units are a "problem element"--especially with mill product specifications calling for 0.02-percent maximum tin. On a more positive note, the use of bimetallic cans (85 percent iron, 15 percent aluminum) provides an added fuel source as a result of aluminum's exothermic reaction in the steelmaking charge.

The Timken Company, Canton, Ohio, also successfully uses steel cans in its electric arc furnace shop, according to Eric Walsky. He noted that the company first started using postconsumer incinerated can scrap in 1987. According to Walsky, over a six-month period involving 100 heats, the program was termed largely successful; but as scrap values increased for this particular type of feed, in Timken's view, the overall benefits did not justify the higher raw material costs. He said residual tin levels also increased and there was some concern that Timken's return scrap ultimately would be contaminated. (This fear was also expressed by Van Rosendale.) Walsky was generally positive about using incinerated material as a feed source, but he said he believes that this type of feed material will remain a very low-value item.

Tin and Zinc Recovery

Tin and zinc recovery also were highlighted during the symposium. Peter Koros, moderator of this session, provided a metallurgical perspective of the two alloying metals in terms of removing tin and zinc from steel. Koros noted concern over the increased usage of galvanized steel products and the effect of large amounts of zinc-containing flat-rolled products that ultimately will return for recycling in this decade and the next.

Detinning of steel was explored by Dick Schulte, AMG Resources Corporation, Pittsburgh. He looked at cans collected from commingled curbside collection programs, from front-end municipal solid waste separation systems, and from material recovered from incinerators. He viewed this last source as "least desirable" in terms of ash accumulation, low metallic yields, and "zero recovery of tin units." Schulte believes, however, that the future for can scrap recovery will be from front-end separation systems.

Stephen Basarab, Proler International Corp., Houston, also looked at tinplate scrap and detinning. According to Basarab, tin contained in tinplate scrap is approximately 6 to 6.5 pounds per gross ton of steel today, compared with 10 pounds in 1960 and 7.5 pounds in 1965. He further calculated that approximately 3.5 million tons of cans are going to landfills every year. His presentation included a detailed look at Proler's Houston facility, which has the capacity to continuously treat 180,000 tons of scrap annually.

Removing zinc units from galvanized steel was reviewed by William A. Morgan, Metal Recovery Industries, Inc., Hamilton, Ontario. The company is currently working with Argonne National Laboratory in developing a process to remove zinc before the coated material goes into a furnace. According to Morgan, the feed material is mostly prompt industrial scrap. The treatment uses a one-step process involving hot caustics and high currents to remove 98 percent of the zinc contained on hot-dipped, electrolytic, galvalume, or galvannealed steels. Morgan noted further that the process is an environmentally "closed system," is low in capital cost, and can use both densified and loose zinc-coated scrap. He expects that this dezincing process will be commercially proven and available by year end.

[SIDEBAR]

Garvey's Good News About Scrap

Robert A. Garvey, president of North Star Steel Company, Minneapolis, was the keynote speaker at AISI's symposium. The company currently operates eight electric furnaces at five facilities in the United States and is considered to be one of the largest purchasers and consumers of ferrous scrap.

Garvey noted at the outset that, with respect to scrap fundamentals, "the good news is that scrap quality and supply will exceed demand for the foreseeable future." As for residual elements found in scrap--of special concern to all melt shops--Garvey said that the issue is "somewhat overblown." However, he also recognized that elements such as copper, nickel, chromium, and tin "will require our attention in the 1990s and beyond."

Examining scrap's supply side further, Garvey cited extensive published research studies that point to rising obsolete scrap reserves. (North Star Steel has calculated a ferrous scrap reserve approaching 1 billion tons.) He said he does not think nonoxidizable residuals are a growing threat; in fact, he admitted to being hard pressed to detect a significant change in residual content among the most commonly recycled grades of scrap. Garvey stated that, in particular, copper, tin, and nickel found in purchased scrap could be controlled by maintaining rigid quality and processing standards. He called for scrap to be treated as a raw material, "instead of as junk."

Garvey also reviewed alternatives to scrap: direct reduced iron (DRI) and iron carbide. He said that despite the fact that DRI is being used in the United States, it is not likely to become a significant source of raw material in the country. Nor is DRI expected to threaten scrap use in Europe or Japan--regions he termed "scrap-rich."