Alutrade Ltd. installed a new sensor-based sorting machine at its Oldbury recycling plant in Birmingham, U.K. The equipment has enabled the company to achieve 99% pure aluminum for use in secondary aluminum production.
As the UK’s largest independent aluminum recycling company, Alutrade processes 42,000 tons of waste annually. The plant’s infeed material is comprised of metal extrusions from different types of post-consumer construction waste (such as windows and doors), as well as aluminum cans.
The company serves remelt operations based all over the world. These operations demand the highest purity grade of aluminum product for their remelting process, as any heavy metal content affects the melt specifications.
The Sorting Process
When the infeed material arrives at the company’s Oldbury plant it is initially pre-shredded into smaller pieces of around 3.3–6.5 ft (1–2 m) 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, the material is processed through a combination of sensor-based sorting equipment from TOMRA Recycling Sorting, which sorts metals based on the difference in atomic density, separating out any heavy metals. Two existing X-TRACT™ units were installed in in 2017 and 2018 respectively, which were programmed to capture a larger aluminum fraction of >1.2 inches (>30 mm).
“Alutrade has been using X-TRACT units for the past four years to guarantee the quality of our products that we supply to our customers,” said Andrew Powell director at Alutrade. “This has enabled us to build up the trust between ourselves and our customers. Right from day one of operation, TOMRA has helped us improve the recovery rates of aluminum in a reliable way. By using X-TRACT units we have been able to upgrade our material so that it could remain in the U.K. rather than be exported.”
Although the two existing X-TRACT units at the Oldbury plant were efficient at sorting larger aluminum fractions, there were some restrictions with smaller fractions. Therefore, Alutrade installed a prototype X-TRACT unit, which utilizes TOMRA’s new x-ray sensor design. This allows the sorting equipment to separate aluminum fractions as small as 0.4–1.2 inches (10–30 mm), removing any heavy metal content from the aluminum and ensuring even higher purity levels.
“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,” said Powell. “The smaller 10–30 mm (0.4–1.2 inch) grain size captured by the new machine is 99% 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.”
In addition to offering superior x-ray capabilities, the new generation sorting equipment includes innovations, such as faster sorting (up to 12.5 ft/sec (3.8 m/sec)) and an increased capacity per meter width. The high-resolution XRT sensor ensures sharper detection and shorter integration times for higher throughput, while a high-power (up to 1,000 W) 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, a secure, nearly real-time and on-demand cloud-based data monitoring platform. This platform generates high value data, helping 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,” explained 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.”