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Out of sorts: nonferrous buying patterns from Asia are changing sorting habits for North American scrap procesors.

Throughout their careers, many scrap processors have spent critical planning and purchasing power devoted to how to best sort metals to provide the cleanest, most segregated grades possible. Certainly, their scrap-consuming customers in North America continue to demand this same amount of attention. But the growing export market to Asia is also causing processors to examine how to best serve this market, which may prefer to do its own sorting closer to home.

Very few processors are willing to predict that automated sorting technology will regress in favor of manual sorting. In fact, even if a production shift to Asia causes a temporary slowdown in advanced sorting research and development, the pause may not last long.

ALL GRADES WELCOME. At times, buyers of scrap for the Chinese market must overcome a stigma that they will accept virtually anything as potential feedstock.

Buyers representing mills and smelters in China have faced a variety of obstacles when entering the global market, including learning the unique trading language assigned to scrap grades by the Institute of Scrap Recycling Industries Inc. (ISRI), Washington.

Even after having learned the differences between "birch" and "cliff" or "twitch" and "zorba," newcomers to the market then discover the truism that no two consumers seem to set the exact same specifications for what they will or will not accept.

Complicating matters has been the vast difference in labor costs between China or india and North America or Western Europe.

Just as many scrap processors grew accustomed to using automation to meet strict chemistry requirements for copper or aluminum shipments, export brokers to China have come into the market willing to buy mixed or crudely sorted loads of metal.

In the short-term, this caused some shredder operators to re-examine their downstream systems to calculate whether it was worth the operating costs to purify metals streams once nonferrous metal was separated from the ferrous portion.

It has also steered some recyclers to do a lot less sorting of loose brass, copper and aluminum scrap, with Chinese consumers able to have this sorting done much more affordably on their side of the Pacific.

Beyond the issues inherent with expanded Asian consumption, ISRI members such as Randy Goodman of Hugo Neu Schnitzer East, Jersey City, N.J., continue to fine-tune definitions and even propose new grades.

In an article submitted to Recycling Today's July 2003 issue, Goodman described an ISRI specifications committee's logic to request a new post-shredder aluminum scrap grade known as "twitch."

Goodman noted that twitch is technically defined as having an allowance of up to 3 percent free zinc, but more commonly the grade has been tied to a product that has been through a heavy media plant, with a "light" or zinc fraction of less than I percent.

This revised definition more closely matches "longthrow," says Goodman, which can have "up to die tolerated 3 percent zinc noted in the specification. Additionally, because the specification does not say that the material must be floated aluminum, longthrow actually more closely approximates the current definition of twitch."

Goodman noted that, "It had been suggested that a new item be defined within ISRI's specifications defining what the world knows as twitch and then make the longthrow item take over the name twitch. The problem with this is that there is an entire international community that thinks that twitch is floated aluminum with a tolerance of 1 percent free zinc. A better solution would be to change the specifications of twitch to meet the commonly accepted parameters of this grade of aluminum and then come up with a totally new 'codeword' for the 'longthrow' type of fragmentized aluminum.' (Goodman recommended something that would make sense in ISRI's alphabetical characterization, such as "twirp" or "twit.") Keeping up with such distinctions requires an ongoing effort for scrap recyclers using separation technology to prepare grades for consuming foundries and mills around the world.

THE HARVEST CONTINUES. Even though to what extent grades must be purified is up for debate, there is still agreement I hat shredder operators wish to pull every ounce of metal out of the "fluff" pile.

Equipment operators continue to work with recyclers to maximize this percentage number--and recyclers have been eager to cooperate as prices for most metals teached historic highs in late 2003 and early 2004.

Magnetic equipment remains a key component of these efforts, as several companies are developing new ways to use magnetic currents to pull metal from the post-shredder stream in particular.

General Iron Industries Inc., Chicago, is running a series of drum magnets, eddy current separators and induction sorting equipment made by Steinert in Germany and sold throught the Steinert US office in St. Petersburg, Fla.

According to Adam Labkon of General Iron, the system has been effective at pulling out materials previously missed or left to the best efforts of hand sorters, including stainless steel fragments, pieces of wire and balled-up nonferrous pieces.

Steinert is just one of several automated sorting equipment companies offering magnetic devices to reach deeper and wider into the post-shredding stream, competing with companies from throughout the U.S. and Europe that provide metal separation equipment.

One equipment company, Eriez Magnetics of Erie, Pa., has even introduced technology that could conceivably help separate key grades of plastic from mixed streams. (Please see sidebar on page 107.)

Shredder makers have increasingly found that the downstream separation systems they help plan and install (usually in cooperation with the magnetic equipment makers) have become a critical part of what they offer customers.

Scrap recyclers have always been receptive to the notion of pulling more metal from the post-shredder stream, but the price boom of 2003 and early 2004 has increased the return-on-investment time for such equipment, spurring an even healthier interest.

Although some sotting may be shifting to Asia, a desire to keep metals in the recycling loop and out of landfills should signal a healthy, long-term trend for separation equipment providers.

RELATED ARTICLE: In the works: magnetic plastic.

Harnessing the power of magnetic currents has long been an effective way to separate and recover scrap metals. Now, researchers are looking at ways to use this same power to improve scrap plastic sorting methods.

Scrap plastic comes in the form of production or processing scrap and from post-consumer streams.

Production scrap can often be components or assemblies consisting of more than one type of plastic bonded together. Because no automated method of grinding and segregating the different types of plastics exists, these components often must be landfilled.

Post-consumer waste contains several types of plastic, which are most frequently automatically separated and should not be incinerated because of the presence of PVC.

Eriez Magnetics of Erie, Pa., has tested and is starting to commercialize two wet gravity processes. Corona and tribo--electrostatic separators can be used for very specific separations, such as the separation of PE and PP.

For automated separation of production scrap consisting of one or more types of plastics, Eriez determined it was necessary to re-engineer the plastic to be separated. A distinctive feature of Eriez' new process consists of manipulating the magnetic susceptibility of plastic polymers with additives.

Magnetic separation, an efficient, high-capacity process well suited for separation of granular material, is based on the ability to attract a particular material exhibiting a magnetic susceptibility and physically segregate it from particles that are nonmagnetic or that have different susceptibility. Magnetic susceptibility is an innate property of a material and is the most important parameter when addressing the characteristics of magnetic separation.

Plastic polymers do not exhibit a natural magnetic susceptibility. Therefore, Eriez engineered a procedure for adjusting the magnetic susceptibility of a polymer. By adding less than 0.5 percent of an inexpensive component to the plastic, Eriez can impart enough magnetic susceptibility to the plastic to make it recoverable using Eriez' high-intensity, permanent magnetic separators.

As a result, an automated process can be established to separate one or more plastics from each other with zero labor cost. Applications for this technology Include the separation of ABS from PE, Pun from PP and TPE from any base material.

If less than 0.5 percent of the additive is used at the time of production, PVCs could be rendered slightly magnetic and separated from post-consumer waste streams. This would allow the waste to be incinerated for energy recovery rather than disposal to a landfill.

--Submitted by Richard Merwin, chairman of Eriez Magnetics, Erie, Pa.

The author is editor Recycling Today and can be contacted via e-mail at btaylor@RecyclingToday.com.
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Title Annotation:Sorting Equipment Focus
Comment:Out of sorts: nonferrous buying patterns from Asia are changing sorting habits for North American scrap procesors.(Sorting Equipment Focus)
Author:Taylor, Brian
Publication:Recycling Today
Geographic Code:1USA
Date:May 1, 2004
Words:1416
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