Automation developed by Danieli Centro Recycling has streamlined shredder productivity at Novelis’ new, state of the art recycling facility in Nachterstedt, Germany.
The 400,000 metric ton capacity aluminium recycling plant is the largest and most advanced in the world. Danieli Centro Recycling has designed and supplied three shredder lines, two of which are dedicated to processing used beverage cans (UBCs), 3XXX and other series scrap, while the third line will process automotive pre-consumer scrap and other suitable end of life, wrought product scrap.
“DCR has drawn on its extensive experience to provide a pioneering workhorse designed specifically with Novelis’ requirements in mind. The plant itself is a step ahead of a fully automatic shredder, and has been designed for non-continuous supervision by the operator.
“In fact, the operator who loads the material also supervises the running of the machine. Meanwhile, on the pre-shredding front, we have developed the most versatile bale breaker on the market. An innovative rotor tooth arrangement increases productivity per unit of power and ensures that small, low density briquettes are just as effectively captured as large, high-density bales.”
The DCR system incorporates the three shredders with a final de-coating and melting process.
Novelis is committed to recycling maximum volumes of aluminium, and the outfit supplied by DCR reflects this. Although UBCs are the most commonly recovered form of aluminium scrap, high-density materials are often mixed with a lower density material stream, resulting in high wear upon more standard shredders. The shredders installed by DCR allow Novelis to process the widest variety of incoming scrap, which is key in responding to market availability and in establishing a robust and successful long-term strategy.
The DCR team opted for an open-type, end-capped rotor conceived specifically to process aluminium. In conjunction with Danieli’s hydraulic pin puller and rotor turning equipment, this design ensures that rotor maintenance is optimized to ensure maximum efficiency. The hammers – which will not wear-harden through operation – are also specifically designed to process more ductile aluminium scrap.
The most significant innovation is the variable speed drive (VSD) on the main motor of the shredder. A VSD controlling a low voltage motor is not only a valid alternative to a direct-on-line medium voltage system, it also results in lower impact on the feeder line during start up and, thanks to continuous torque control, reduced motor stress levels. Other benefits include fully configurable motor torque limit; reduced initial and operating costs; greater machine flexibility, and safer operation – rotor stoppage takes one minute as opposed to 30.
– each fed by a dedicated bale breaker
The presence of unshreddable objects in the shredder charging feed is a common issue, typically controlled through constant operator supervision. Although relatively effective, this calls for high personnel costs, so Danieli instead developed the Q-ARDC Automatic Reject Door Control system, which employs noise and vibration monitoring to detect the presence of unshreddable material. The charging feed is then arrested and, following a delay to limit the expulsion of shreddable material inside the machine, the door is opened.
In order to prepare high-density material which cannot be fed directly into the shredder, a bale breaker is a must. “By delivering opened and de-densified material, the DCR bale breaker reduces the effort needed for the shredder to process and bring material to furnace specifications. This results in increased productivity and working life of shredder wear parts, and a reduction in fines created by high-speed shredder action – due to material staying inside the shredder for a longer time.”
Gianmatteo Martinelli, Director of Operations and Engineering, Novelis Europe, summed up: “An open-minded approach to new challenges and reactiveness to business needs are the key drivers for successful projects. Additionally, Danieli’s close presence to the shop floor and good understanding of the operational and preventive maintenance requirements can make a difference for Novelis.”