Metals separator developed for very fine materials

Sorting specialist STEINERT has developed a non-ferrous metals separator for fine materials, which it supplied to metal recycler Galloo. The system’s splitter can be set with millimetre precision, enabling non-ferrous metals such as aluminium, copper and zinc to be efficiently separated.

In 2013, Galloo began to look into more efficient ways of extracting non-ferrous metals from fine-grain material. Galloo contacted the engineers at STEINERT, asking them to develop a flexible machine concept for three different input materials: automobile shredder residue (ASR), incineration bottom ash and electronic scrap.

The challenge was that the input is extremely fine material, with grain sizes of 0.5 to 10 mm. The goal was to enable the three different materials to be to run through the system flexibly, without any drop in the separation rate. Engineers wanted to further optimise the separation of non-ferrous metals out of the fine-grain fraction and, at the same time, simplify operation and maintenance.

STEINERT developed a splitter that can handle the three different types of material. Fine gearbox adjustments can be made to the splitter to enable it to get to within a few millimetres of the material. The machines now run at Galloo for about 16 hours per day.

STEINERT’s development and design team next began to work on additional features for the fine-grain sector, leading to the creation of the STEINERT EddyC FINES — a machine with a frame structure which allows the belt to be replaced in 10 minutes.

“Changing the belt of an eddy current separator often takes a company half a day, with up to three employees and heavy lifting equipment needed to perform this task,” said STEINERT Technical Director Dr Nico Schmalbein. With the STEINERT EddyC FINES, two employees can carry out a belt change with nothing more than a spanner.

Galloo is now using the STEINERT EddyC FINES to recover non-ferrous metals from grate ash. Not only are the particles very small, measuring only 0.5 to 4 mm, but the system’s splitter plate has to be precisely adjusted in order to separate the metals from the fine incineration bottom ash material.

“A gearbox now enables users to set the splitter plate with millimetre precision along three different axes and adjust it even more accurately to the parabolic trajectories of a wide variety of materials,” said Schmalbein.

The metals separator also has a rapidly rotating magnetic pole system that induces eddy currents in the non-ferrous metals transported on the conveyor belt. The resulting opposing magnetic field creates repulsion effects, which enables the non-ferrous product to be ejected from the stream of material. The splitter plate in the parabolic trajectory separates the non-ferrous product from the remaining stream of material.

“We made sure the splitter plate was adjustable so that the system can react to a variety of input materials,” said STEINERT Design Engineer Jochen Schäfer. “Before we did this, we analysed the flight properties of various materials and used this information to work on the settings. The splitter can be adjusted to specific trajectories in order to accommodate a variety of separation tasks.”