Equipment makers strive to help auto shredding plant operators recover all their metal.
As metals prices have tripled in value (or more) in the past several years, shredding plant operators have turned to equipment suppliers to help them ensure that no metal is discarded as auto shredder residue (ASR).
Darrell Milton of equipment maker Eriez, Erie, Pa., speaking at a session of the World Recycling Forum, held in Hong Kong in mid-November, outlined how metals recovery and separation systems have evolved in the past two decades.
Milton said that drum magnets stand first in line behind an auto shredder to pull out the ferrous pieces and thus “handle 75 percent of the saleable product [by volume]” that is produced by a shredder.
The remaining stream then is exposed to eddy current separators that “repel conductive material using opposing magnetic fields.” The eddy currents, said Milton, are “very effective on aluminum and copper,” capturing as much as 95 percent of these metals, but are not effective on stainless steel.
Shredder operators thus commonly turn to induction sensor sorting units to recover the stainless portion and more of the remaining aluminum and copper fragments.
Milton added that Eriez also has been marketing a fines recovery system that “catches small pieces of ferrous scrap, aluminum and other metals that previously were sent to the landfill.” Depending on a shredding plant’s capacity, this final step can catch from five to 10 tons per day of additional metal, said Milton.
At the same session, Siegfried Lohmeier of Germany’s Hammel Recyclingtechnik GmbH provided an overview of his company’s mobile auto shredding system.
The system can be comprised of up to four mobile pieces: a primary Hammel “Red Giant” shredder; a finger screen; an eddy current separator; and a “fines shredder” that can help produce a more marketable ferrous shred end product.
The Hammel system can handle car bodies, appliances and small bales of scrap metal, said Lohmeier. He added that it was “suitable for small and medium-sized businesses” and that Hammel customers such as Universal Recycling Co. of Johannesburg, South Africa, have been transporting the system to work through inventory at different company locations.
The system can be moved, said Lohmeier, with three flat-bed trucks and one hooklift truck.
The 2011 World Recycling Forum, hosted by ICM AG, was Nov. 15-18 in Hong Kong.