Rotorshredder makes recycling meatballs even more efficient

June 2019

The reference at a glance


Increase efficiency in processing meatballs


Rotorshredder and rotor impact mill

Operating site





Separation of valuable materials from meatballs


New process to increase the copper yield

BHS-Sonthofen has developed a new procedure for processing meatballs in order to increase the amount of copper recovered. Electric motors and motor armatures represent a small fraction of waste from incineration or large shredders, and it is difficult to cleanly separate them by type. Yet they contain a good deal of valuable copper, whose share is up to 22 percent. This impressive new procedure features a Rotorshredder optimized for this process, subsequent materials separation and copper processing using a rotor impact mill.

A Dutch customer wanted to optimize a process for recycling electric motors and motor armatures in order to significantly increase non-ferrous metal concentrations. This request was based on ever-increasing demand for high purity metals. The traditional method uses a hammer mill to crush the meatballs. Given the traditional design of the hammer mill, crushed parts come into contact with each other. The resulting new metal compounds become entangled and subsequently almost impossible to separate into homogeneous fractions. In addition, the hammer mill’s ejectors are designed in such a way that the individual parts inevitably get caught. The greatest challenge lay in treating the materials in a manner such that clean separation could be achieved.

The experts at BHS have many years of experience as well as in-depth knowledge of the process – and this paid off. A thorough analysis of the process was undertaken together with the customer, and different intensive tests were carried out using the customer’s material at the BHS test center. The result is a solution that improves the process in several ways, one that is specifically tailored to this specific application. The meatballs are selectively broken down in the BHS Rotorshredder. The ejection system is also designed in such a way that the shredded parts drop down across the full width of the discharge conveyor belt and do not come in contact with each other again. This ensures that the material cannot become entangled.  

After material discharge, the shredded metal is transported under an overhead magnet mounted alongside the discharge conveyor belt to separate the ferrous fraction from the rest of the material. BHS also optimized this process. If the overhead magnet had been installed at a right angle to the conveyor belt, as would typically be the case, longer iron parts would drag over the belt and become entangled with other parts. Thanks to this optimization, the remaining parts move along the conveyor without becoming caught or stuck on the belt. A cross-flow sifter then uses a stream of air to release the copper portion of the material from stainless steel parts and heated, non-magnetic iron parts. The rotor impact mill (RPMX) is well suited for removing impurities from copper fractions extracted from the material. The RPMX for recycling applications stands out because of its higher circumferential speed and a smaller milling gap. The result is a high-quality metal concentrate that is of the same quality as copper recycled from cables.