Alutrade is using TOMRA's X-TRACT, a new sensor-based sorting solution. The X-TRACT is one of TOMRA's advanced X-ray metals sorting units and 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 in length before being further shredded by a hammer mill. Magnets and eddy current separators are then used to separate the metals into ferrous and non-ferrous metals, removing any contaminants in preparation for the next sorting stage.
Following magnetic separation, a combination of TOMRA sensor-based sorting units are 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 less than 1.2 inches, and the new machine targets a smaller 0.4 to 1.2-inch 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.
Meeting industry demand for recycled aluminum
Alutrade's customers are remelts based all over the world who want a high purity grade of aluminum for their remelting process as any heavy metal content affects the melt specifications.
"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," explains Andrew Powell, director at Alutrade LTD. "The smaller 10 to 30mm (0.4 to 1.2 in) 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."
The new X-TRACT
Although the two earlier edition TOMRA X-TRACT units at the Oldbury plant allowed Alutrade to capture the less than 1.2 inch aluminum fraction, there were some restrictions on smaller fractions. However, thanks to a new X-ray sensor design, the new X-TRACT can separate fractions down to 0.2 inches (5mm) 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 stronger X-ray capabilities. The software-based solution helps to guarantee premium remelt quality recycled aluminum by ejecting the heavy metal contaminants.
The new generation X-TRACT unit has several new features, including faster sorting and an increased capacity per metre width. A new 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 connected to TOMRA Insight, TOMRA's cloud-based data monitoring platform. The platform enables users to turn their sorters into connected devices and to transform sorting from an operational process into a strategic management tool. The platform helps generate operational data, TOMRA Insight helps to maximize plant throughput, boost sorting performance, and optimize output quality.
"Investing in the new X-TRACT has enabled us [Alutrade] 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. "With low operational costs, improved safety and superior sorting capabilities, the new X-TRACT definitely stands out in terms of the aluminum recycling solutions available in the global metals recycling market."
