While many of the world’s major metals processors rely on shredders in support of decarbonisation goals and material recovery efforts, these same operators face a number of challenges, including a high incidence of fires in material piles and customers’ stringent quality demands. Both these issues were addressed at the meeting of the Shredder Committee held in Valencia on May 26.
Fires had become far more commonplace as a result of the growing presence of the ubiquitous lithium battery, explained George Adams of SA Recycling in the USA. “We’ve got 150-plus yards across the country, and maybe I don’t get a fire every day — but I bet we get a fire every other day,” he told delegates.
The best way to minimise fires, he added, was to avoid building piles of material. “It’s really simple — ship to the ground,” he underlined. But he also urged shredder operators to prepare fully for the possibility of a fire. His own business kept water storage containers on stand-by at yards so that they could be grabbed by a crane and deployed immediately. “You can literally have water in minutes (and) nobody ever gets in any danger,” he explained.
He also stressed the importance of having water pressure and of spraying the fire from multiple angles. “And it doesn’t do any good to have fire hoses and to have things set up if you don’t do fire drills,” he added. “Our guys are required to do a fire drill once a month. They have to turn in a video once a month of the different drills.”
For those who believed such preparations to be unnecessary, expensive and/or time-consuming, Mr Adams had the following stark message: “A fire can cost you millions of dollars in lost reputation. Some companies have had criminal charges filed against them because they had a fire.”
Karl Hoffmann of the Metal Recycling Division at Steinert GmbH in Germany focused his guest presentation on three technologies designed to deliver the high-quality, low-copper recycled material required by steel mill customers. In the case of HMS, for example, his company aimed to remove more than 90% of impurities “in a very easy way” by orientating one of its magnetic drums above a feeder so that the ferrous content was lifted out whereas non-ferrous and non-magnetic components of the material stream fell through a gap between the drum and the feeder tray.
Meanwhile, the Steinert SteelMaster used a balance between ballistic and magnetic forces such that meatballs — which come with a lot of windings and create a high copper content — were less attracted by the magnetic field but, with higher ballistic force, ended up in the impurities for hand-picking. Siting another magnetic drum after the SteelMaster recovered a further 7-8% of iron material such that, at the end, “we have 85-88% of steel mill-ready fraction, with less than 0.2% of copper”, the speaker explained.
Another Steinert approach combining X-ray fluorescence with other sensors and an element of AI was said by Mr Hoffmann to create very efficient results. “It’s not just ballistics and magnetics — it’s programming,” he told delegates. “It’s also a very flexible machine — that means it’s also something you can use for the future with regards to different programming possibilities.”
In the final guest presentation, Manuel Andreis of Eriez Magnetics Europe featured the Shred1 Ballistic Separator in which copper-bearing cable armatures, for example, were influenced more by the speed of the belt than the attraction of the magnet. Therefore, less magnetic materials — such as those with a high copper content — were launched away by ballistic force. “The difference to our competitors is that our magnet is a permanent magnet so doesn’t need power or any external force to run,” he noted. “You just need to run the belt to the desired speed.” He listed the following advantages of this approach: the process was almost fully automated; capacity was high and delivered a consistent quality of material; and labour requirements were reduced at a time when new workers were hard to recruit. He also acknowledged that the overall system was quite large, with machine and feeder together measuring around 10 metres in length and a maximum three metres in width.
