Alutrade recovers 99 percent pure aluminum with TOMRA X-TRACT

Alutrade, the U.K.'s largest independent aluminum recycling company and extrusion specialist, is the first company in the world to utilize X-TRACT, the new sensor-based sorting solution from TOMRA Recycling Sorting. The X-TRACT has enabled Alutrade to achieve 99 percent pure aluminum for use in secondary aluminum production.

The new X-TRACT unit was installed in March 2021 at Alutrade's Oldbury recycling plant in Birmingham, U.K., which processes 42,000 tons of waste annually. The plant's infeed material comprises metal extrusions from different types of post-consumer construction waste, such as windows and doors, as well as aluminum cans. 

A combination of mechanical and sensor-based sorting  

When the infeed material arrives at Alutrade's Oldbury plant, it is initially pre-shredded into smaller pieces of around 3.3 to 6.5 feet (1 to 2 m) in length before being further shredded by a hammermill. Magnets and eddy current separators are then used to separate the metals into ferrous and non-ferrous, removing any contaminants in preparation for the next sorting stage.  

Following magnetic separation, a combination of TOMRA sensor-based sorting units is used to process, sort, and recover the target fraction of aluminum. Two of the earlier edition TOMRA X-TRACT units - which were installed in 2017 and 2018 respectively - are programmed to capture a larger aluminum fraction of >1.2 inch (>30mm), and the new machine targets a smaller 0.4- to 1.2-inch (10 to 30mm) aluminum fraction, removing any heavy metal content from the aluminum. Both the earlier and new edition X-TRACT units sort metals based on the difference in atomic density, separating out any heavy metals.    

An industry demand for premium recycled aluminum

Alutrade's customers are remelts based all over the world who require the highest purity grade of aluminum product for their remelting process as any heavy metal content affects the melt specifications. 

Andrew Powell, director at Alutrade, explains: "Over the past five years, we have worked closely with TOMRA and our main customer and have undertaken a lot of research to achieve this milestone of recovering an aluminum end fraction that meets the exceptionally high purity levels required to go straight into the remelt process. The smaller 10- to 30-mm (0.4- to 1.2-inch) grain size captured by the new machine is 99 percent pure aluminum which means we can sell it at a much higher price to our customers for use in the production of new aluminum products. What's more, the new version of X-TRACT has opened up new international market opportunities for Alutrade as we can now source different infeed material, as well as sell on the ejected heavy metal products." 

Although the two earlier edition TOMRA X-TRACT units at the Oldbury plant allowed Alutrade to capture the >1.2 inch (>30mm) aluminum fraction, there were some restrictions on smaller fractions. Due to a new X-ray sensor design, the X-TRACT can separate fractions down to 0.2 inches (5 mm) at even higher purity levels.

TOMRA's new X-TRACT uses the same process of separating metals by atomic density as the earlier edition but offers enhanced X-ray capabilities. The software-based solution can guarantee premium remelt quality recycled aluminum by ejecting the heavy metal contaminants. 

The new-generation X-TRACT unit features a number of new features, including faster sorting up to 12.5 feet/sec (3.8 m/sec) and an increased capacity per metre width. A new high-resolution XRT sensor ensures sharper detection and shorter integration times for higher throughput, while a high-power (up to 1,000w) X-ray source is capable of processing multiple applications and grain sizes. An extended separation chamber reduces material loss by improving the trajectory of sorted objects and a new catcher hood ensures safer access and faster maintenance. 

Alutrade's X-TRACT unit is also connected to TOMRA Insight, TOMRA's nearly real-time, cloud-based data monitoring platform. The platform enables customers to turn their sorters into connected devices and to transform sorting from an operational process into a strategic management tool that helps to maximize plant throughput, boost sorting performance, and optimize output quality. 

"Investing in the new X-TRACT has enabled us to close the loop on the recycling process as much as possible, converting aluminum back into aluminum for use in high-grade aluminum products so that, in effect, a window frame can be recycled into a new window frame," says Powell.

Terence Keyworth, TOMRA's segment manager of metal recycling for North/East Europe, adds: "TOMRA and Alutrade have worked together for more than ten years, so Alutrade's Oldbury plant was an ideal plant for us to test and prove the capabilities of our new X-TRACT. As the first prototype of this unit in an industrialized environment, it has been a very exciting project. We're delighted that Alutrade has been so impressed with the sorting capabilities of this new technology and look forward to rolling out further installations over the coming months."