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New TOMRA X-TRACT for magnesium removal produces furnace-ready Twitch

X-ray sorting technology upgrade allows scrap recyclers to separate magnesium from aluminum to purity required for domestic markets

TOMRA X-Tract test centre
TOMRA X-Tract for magnesium removal, at the testing centre.

TOMRA Sorting Recycling has introduced X-TRACT for magnesium removal. This first-of-its-kind x-ray-based solution can separate magnesium from aluminum in Zorba and other mixed scrap to unprecedented levels. 

For auto shredders and scrap recyclers, X-TRACT for magnesium removal offers a reliable, robust and cost-effective alternative to sink-float separation, opening up new domestic markets for low-magnesium Twitch. (Secondary aluminum smelters in domestic markets require aluminum Twitch produced from Zorba to contain below 0.5 percent by weight of magnesium content, due to its high combustibility and potential to cause explosions in  furnaces.)

According to Brian Gist, global sales director metals at TOMRA Sorting Recycling, this brings to the recycling industry, for the first time, a robust sensor-based sorting technology for removing magnesium from small-sized size aluminum fractions. 

He says before this kind of technology, recyclers using sensor-based sorting simply could not get this high-level magnesium-aluminum separation when processing Zorba. Or they would have to use float-sink media-plant technology, which he says is now more than a half-century old technology. 

"We are thrilled to be the first company in the world to create furnace-ready products using sensor-based sorting, including Low Magnesium Twitch, across the full Zorba size spectrum," comments Gist. "This was previously only accomplished through a two-stage float-sink process."  

"The difference this technology brings is that it allows the user to go to a sensor-based sorting machine, turn it on, turn the infeed conveyor on and the feeder, put material in, and let it remove the magnesium. Literally it is as simple as that. 

"Compared that to what we had before, this is a game-changer."

TOMRA's X-Tract sensor-based sorting system has been upgraded to efficiently separate magnesium from aluminum in the Zorba pile.

The upgraded  X-TRACT for magnesium system uses existing TOMRA XRT x-ray based technology in a new configuration, with enhancements made to the software, firmware and hardware. The system sorts material of different density levels and separates magnesium from aluminum to create furnace-ready product, with specifications from 0.2-4.7 inches (5-120mm). 

"With X-TRACT for magnesium removal, we have greatly reduced the commercial and operational barriers to sorting this material and can offer a proven alternative to replace dense media plant technology for separating magnesium from aluminum," continues Gist, adding that field test results to date have been extremely positive with regard to machine reliability, robustness and sorting stability. While testing has not occurred in the UK, there has been extensive testing so far in the U.S. and Europe.

ZORBA is derived from shredded and pre-treated non-ferrous scrap metals, usually originating from ELV or or WEEE recycling.

Upgraded technogy for a changing market
The United States generates an estimated 4 million tons of Zorba annually, which typically contains between 2% and 4% magnesium. Historically, scrap metal processors exported the bulk of this material to China. Changes to China's scrap import policies regarding purity and trade tariffs have created significant barriers to exporting over the past couple of years. 

Limited export opportunities have resulted in a surplus of Zorba scrap in the North America. A growing domestic market for furnace-ready material produced from Zorba offers scrap operations an opportunity to profit from this surplus. The challenge scrap metal processors face, however, is secondary aluminum smelters in domestic markets require the aluminum from Zorba to contain exceptionally low magnesium, well below 0.5% by weight. 

Team TOMRA Recycling in front of a large pile of Zorba.

Until now, the only way of treating Zorba for the removal of contaminants such as magnesium has been a two-stage sink-float operation. Initially, the heavy metals are separated from the shredder scrap, while the hollow aluminum scrap, magnesium and high-density plastics are floated out in an additional media stage. Sink-float processes have historically been difficult to manage, require a large footprint, can be relatively unstable and have a relatively high operating cost-per-ton. 

Eric Thurston, North American sales manager metals - recycling for TOMRA Sorting Recycling says there is a strong internal domestic market for Low Magnesium Twitch production, but the high purity requirements of secondary aluminum smelters have previously hampered metal processors' access to the market. X-TRACT for magnesium removal eliminates the purity barriers and offers many significant benefits to scrap metal processors. 

"Beyond accessing new and growing domestic markets, adding X-TRACT for magnesium removal to the sorting line increases the market value of the aluminum, minimizes material losses, and greatly reduces reliance on costly and risky manual sorting," comments Thurston. 

"Our new X-TRACT technology is an ideal solution for both small and large operators. Rather than selling material at a lower price to larger operators for further processing, smaller scrap yards can invest in just one machine and trade furnace-ready aluminum on the domestic market. This expands the company's customer base and allows it to increase its profitability."   

Gist adds, "If I'm a processor and I'm making Zorba with 4% to 6% zinc magnesium in it, I can't sell it, or I can sell it to another recycler who has the right equipment because of the scale of their business." 

In either case, he says, the value is lost, and this is why X-TRACT for magnesium removal is a game-changer. "If I've got a shredder in the U.S., I am making a mag-content Zorba, and I need to try to make a twitch -- a magnesium-free or low-magnesium product that i can sell right away. If I can do this, this is great. If I can do this at low cost, with low operation cost and low purchase price for capital equipment, it's a winner. If I own a shredder in the U.S., I need to do this, and I need to do it yesterday."

Company info

875 Embarcadero Drive
West Sacramento, CA
US, 95605


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