November/December 2003
By using tire wire in its melts, Gerdau AmeriSteel is building a market for this fledgling scrap material, expanding its raw material supplies, and keeping a useful feedstock out of the landfill. What’s not to like about that?
By Kent Kiser
About 20 miles from downtown Jacksonville, Fla., in the town of Baldwin, Gerdau AmeriSteel Corp. is conducting an important scrap experiment. Specifically, the company is using tire wire in the scrap mix for its rebar products.
This may not seem like a big deal, but in reality it is a bold move, full of challenges and risks for both Gerdau and its tire-wire supplier, Florida Tire Recycling Inc. (Port St. Lucie, Fla.). By working together, however, these diverse partners are pioneering a market for tire wire and, in the process, helping establish the material as a
full-fledged scrap commodity.
A Long, Slow Road
This success story hasn’t come quickly or easily for both technological and market reasons.
Until about the mid-1990s, for instance, tire processing machinery wasn’t sophisticated enough to produce a clean tire-wire product. Even then, it was common for tire wire to have a high level of rubber contamination—such as 30 percent—which made it unfit as a raw material for most mills.
Aside from technical hurdles, tire recyclers faced the daunting task of persuading steel mills to even try the material. The good news was that a handful of domestic mills accepted some sample loads. The bad news was that many of these early experiments failed due to quality problems (too much rubber content), packaging/handling problems (the material was too unwieldy and inefficient to load in its loose or loosely baled form), and/or supply problems (insufficient clean tonnage available on a reliable basis).
Given these challenges, many tire processors simply landfilled their tire wire, stored it in hopes of a future market, or left the metal in the rubber chips they sold as tire-derived fuel.
Tire recyclers clearly had their work cut out for them. If they hoped to establish a market for tire wire, they had to find a way to create a clean product that addressed steelmakers’ quality, packaging, handling, and supply concerns. Fortunately, this was one challenge that Florida Tire Recycling was willing to face.
Getting the Wire Out
Like many tire recyclers, Florida Tire generates thousands of tons of tire wire a year in the process of making its various rubber products. Jack Wilson, the firm’s president, knew he had to find a market for this material.
So, about 18 months ago, he approached Gerdau AmeriSteel with the idea of adding tire wire to its scrap mix. To his good fortune, he found a sympathetic and farsighted partner in Vicki Roche, Gerdau’s director of raw materials. Roche—in cooperation with Michael Orand, scrap purchasing manager at the Baldwin mill—persuaded the mill to accept some trial loads of the material.
These initial loads contained loose wire, which was difficult to handle and which degraded rapidly. Florida Tire quickly realized it had to not only get more rubber out of the material, but it also had to package the wire better to increase its density and minimize handling problems.
The company achieved those goals thanks to equipment from Eldan Scandinavian Recycling A/S (represented in North America by Wendt Corp.) and Columbus McKinnon Corp. Using two Eldan heavy raspers and a prototype system named the Liberator from Columbus McKinnon, Florida Tire was able to achieve better separation of tire wire from the rubber. After passing through two magnets, the clean wire is conveyed to a briquetter from Wendt Corp. while the rubber heads for further processing. The end product? Dense tire-wire briquettes that are about 98-percent free of rubber, says Jack Wilson.
About six months ago, Gerdau began accepting trial loads of this new-and-improved tire wire, and the results were much more positive. A new scrap market was being born.
Into the Mix
It’s a Friday morning in late September, and a tractor trailer from Florida Tire is backing up toward the scrap bay at Gerdau’s Baldwin mill. After opening the trailer doors, the driver activates the trailer’s walking floor to begin unloading the contents—about 23 tons of tire-wire briquettes. As the trailer rolls forward, the neatly stacked bricks tumble out, forming a mini-mountain of tire wire in the mill’s shadow.
Given its limited indoor storage space, the Baldwin mill must stage its scrap outside. This isn’t a problem for its principal grades like shredded, heavy melt, and cast iron. For tire wire—which has a lot of surface area to oxidize—the warm, moist, sunny Florida environment can cause it to rust and degrade rapidly. This was more of a problem when the tire wire arrived loose. Briquettes can withstand the elements better because they have less exposed surface area. Still, tire-wire briquettes are relatively permeable and, hence, will begin to rust—at least on the outside—within days.
To address these storage and degradation issues, Gerdau only accepts tire wire in quantities it can use quickly—usually two to three truckloads a week (though the mill reportedly plans to increase this level to one truckload a day).
Once the tire wire briquettes are unloaded, they wait their turn in the charge—and not just any charge. For quality reasons, Gerdau can only use tire wire to make rebar, not its low-carbon steel products such as wire rod. Even in its rebar melts, Gerdau has specific parameters that govern its use of tire wire. According to Ed Katai, senior process engineer, the mill uses about 4,000 pounds of tire wire per 100-ton heat, which equates to about 2 percent of the raw material charge for rebar.
Gerdau must charge three buckets of scrap—one 50-ton bucket, one 30-ton bucket, and one 20-ton bucket—to create the 100-ton heat, which yields 92 tons of liquid steel. Tire wire goes into the 50-ton bucket (which is loaded first), and it is about the fifth item layered in the bucket along with turnings scrap.
Loading the tire wire into the charging bucket has become much easier and more efficient since the material has been briquetted, say mill personnel. That’s a welcome change from the days when the material was sent loose. Then, it clung together in big Brillo-pad-like clumps, creating a handling nightmare and preventing the scrap-loading magnets from picking up any worthwhile tonnage per lift. The loose wire also left short, sharp lengths of wire everywhere, creating a mess in the scrap bay. Now, notes Ed Katai, “the handling of briquettes is pretty good.”
After being charged into the furnace, the tire wire and other scrap are melted to the target casting temperature of 3,050 degrees F. During the melting stage, Gerdau must make sure that the residual rubber in the tire-wire briquettes doesn’t elevate the amount of sulfur in the steel to an unacceptable level. Rebar can have a maximum of only 0.07 percent sulfur in the mix, Katai says, noting that the mill adds 4,500 pounds of bulk lime per rebar heat to pull impurities (such as sulfur) from the melt and capture them in the slag.
While the rubber content of tire wire could, in theory, add carbon to the melt and, thus, reduce the mill’s use of supplemental carbon, the fact is that Gerdau doesn’t use enough tire wire for the rubber to be beneficial in any significant way, Katai states. Instead, the mill relies more on the 3 percent carbon content in the cast iron scrap it uses. Even with that, the mill must add 800 pounds of charge carbon to its rebar melts.
The bigger question—at least for Gerdau’s mill staff—is: What does tire wire add to the melt in terms of its metal content, or “yield” in steelmaker lingo? The answer is far from clear. Some Gerdau staff say tire wire’s yield is 70 to 80 percent, while others say it’s more like 60 percent. Still others offer only that tire wire has a lower yield than turnings, though they note that briquetting the material has increased its density and, thus, perhaps boosted its yield. “We don’t have a decent feel for the yield,” Katai concedes, explaining that the mill “can’t use enough to get a feel for it.”
Without such knowledge, you could say that Gerdau is using tire wire, in part, as an altruistic gesture and, in part, as an act of enlightened self-interest. On the altruistic side, the mill is certainly going the extra scrap mile to help establish a viable market for this fledgling material. Vicki Roche, in particular, has personally led the charge to develop this market. Her efforts include serving on ISRI’s task force on tire wire, which accomplished the landmark task this year of creating standard specifications for tire wire (see “Tire Wire Makes the Grade” below). She also spoke about tire wire at a tire recycling workshop at ISRI’s annual convention in April. Perhaps most importantly, she and Michael Orand have marshaled the support of Gerdau’s mill staff despite the numerous challenges and inevitable resistance involved in introducing a new raw material into the scrap mix. “If it wasn’t for Vicki,” says Orand, “this wouldn’t be happening.” Florida Tire’s Jack Wilson concurs, adding that “Vicki has played a big part in this, and she has been very, very helpful. She has been willing to take a chance on the material.”
That said, there is a measure of enlightened self-interest at work here as well. In periods of high ferrous scrap prices and in light of growing export demand for U.S. scrap, tire wire can give domestic steelmakers—such as Gerdau—a new scrap feedstock. According to one estimate, U.S. tire recyclers could recover some 40,000 tons of tire wire annually. That’s not a huge quantity compared with the millions of tons of ferrous scrap consumed each year by U.S. steelmakers. Still, any additional source of metal-lics is a good thing, especially if it’s reasonably priced.
How reasonably priced? All Gerdau will say is that it buys tire wire at a discount to turnings and that the price fluctuates with the market. As Katai explains, “We can use the material, but we’re not recovering as much iron out of it so the price has to reflect this lower yield. We’re using it to help dilute our costs.” For now, any market for tire wire—even a modestly priced one—is better than sending the material to the landfill, Gerdau staff suggest.
A Great First Step
So, where will this grand tire-wire experiment lead from here?
In Jack Wilson’s view, tire wire is just beginning its market evolution. At this stage, the focus is on gaining mill acceptance of the material. The important points for mills are cleanliness of the material, density, ease of handling, consistent volume, and—of course—price. After all, he notes, “there has to be an incentive for them to use it.”
Once tire wire proves itself in the market, however, mills could begin competing for the material, and prices could then be based on supply-and-demand conditions like other grades of ferrous scrap. “Once you establish that there’s a market for tire wire and it becomes mature,” Wilson says, “then you’ll be able to sell the material for something other than a discounted price.”
In the long run, then, will tire wire be as accepted and in-demand as other grades of ferrous scrap? It already has its own standard ReMA specifications. Eventually, it could become a genuine commodity in its own right, with its own published price. That transition won’t happen overnight, and it won’t be an easy road.
With supportive mills like Gerdau AmeriSteel and committed scrap buyers like Vicki Roche and Michael Orand, however, tire wire seems to have a promising future. “We’re trying to help that along,” Orand says, with Wilson adding, “We’ve got a great first step here.”
Tire Wire Makes the Grade
In April, ISRI’s board of directors approved a list of 11 specifications for steel from scrap tires. These specs were developed by a special ReMA task force on tire wire, which included representatives from the steelmaking, tire processing, and equipment manufacturing sectors. The tire-wire specs (below) are included in ISRI’s 2003 Scrap Specifications Circular as part of the overall “Guide-lines for Ferrous Scrap.”
Steel From Scrap Tires
General Guidelines
Items not covered in the specifications, and any variations in the specification, are subject to special arrangement between buyer and seller. Percentages listed below are by weight.
Preparation
Consumer and supplier to agree upon preparation for transport, such as the following:
Loose—Whole
Loose—Chopped. If wire is chopped or shredded, parties may wish to specify the means of processing and/or characteristics of the final product (density, length of pieces, etc.).
Baled. Bales of wire should maintain their form during loading, shipment, unloading, storage, and handling typical of that done at a consuming facility, unless otherwise specified.
Baled—High Density. Hydraulically compressed, no dimension larger than 24”, density of at least 75 pounds per square foot.
Baled—HRB/Low Density. Density of less than 75 pounds per square foot. Each bale secured with sufficient number of bale ties drawn tight to insure a satisfactory delivery.
Other Means of Preparation. Individual specifications to be agreed upon between consumer and supplier.
272 Pulled bead wire (Truck)—Grade 1. Not chopped; made up of loops of wire. Less than five percent (<5%) rubber/fiber.
273 Pulled bead wire (Truck)—Grade 2. Not chopped; made up of loops of wire. Five to ten percent (5-10%) rubber/fiber.
274 Pulled bead wire (Truck)—Grade 3. Not chopped; made up of loops of wire. Greater than ten percent (>10%) rubber/fiber.
275 Pulled bead wire (Passenger)—Grade 1. Not chopped; made up of loops of wire. Less than five percent (<5%) rubber/fiber.
276 Pulled bead wire (Passenger)—Grade 2. Not chopped; made up of loops of wire. Five to ten percent (5-10%) rubber/fiber.
277 Pulled bead wire (Passenger)—Grade 3. Not chopped; made up of loops of wire. Greater than ten percent (>10%) rubber/fiber.
278 Processed tire wire (Ferrous)—Grade 1. Chopped. Less than two percent (<2%) rubber/fiber.
279 Processed tire wire (Ferrous)—Grade 2. Chopped. Less than five percent (<5%) rubber/fiber.
280 Processed tire wire (Ferrous)—Grade 3. Chopped. Five to ten percent (5-10%) rubber/fiber.
281 Processed tire wire (Ferrous)—Grade 4. Chopped. Ten to twenty percent (10-20%) rubber/fiber.
282 Processed tire wire (Ferrous)—Grade 5. Chopped. Greater than twenty percent (>20%) rubber/fiber.
Kent Kiser is publisher and editor-in-chief of Scrap.•
By using tire wire in its melts, Gerdau AmeriSteel is building a market for this fledgling scrap material, expanding its raw material supplies, and keeping a useful feedstock out of the landfill. What’s not to like about that?