Steinert Sensor Sorting Technology Processes Incineration Slag

Steinert says its Sensor Sorting Technology is being used to recover more value from incineration slag by recovering nonferrous metals as small as 3 millimeters in size.

Cologne, Germany-based Steinert  has been building its eddy current separators, Steinert NES units, with an eccentric pole system since 1987. Over the years Steinert says it has improved and optimized its patented design. More than 3,500 units have been delivered to date, including more than 600 units equipped with the eccentric pole systems.

With feedback from its customers, the company has developed the fine pole system 6119, the rotors of which have 19 pairs of poles. Steinert says it is possible to increase the rotational speed of the rotors in this system from 2,600 to 3,000 rpm while retaining their eccentric arrangement.

One of the first customers to install the new generation of Steinert NES is the slag processing company Stork Umweltdienste GmbH at its site in Magdeburg, Germany.

With the improved version of Steinert’s fine pole system, customers can achieve improved separation of nonferrous metals, even in the size range of less than 3 millimeters, according to the company.


The recovery of precious metals and stainless steel contained in slag using induction sorting systems (ISS) is at the forefront of developments in this sector, Steinert says. This is in addition to the traditional processing of refuse incineration slag by means of preclassification, hand sorting, air separators, magnets and eddy current separators.

By using specially designed sensors, ISS can detect and sort out the precious metals contained in the refuse incineration slag. Yield rates of greater than 90 percent can be achieved and the products being recovered have very high levels of purity, according to Steinert.

In terms of processing procedure, ISS units are used downstream of the traditional sorting methods mentioned above. In most cases, Steinert says, the acquisition of ISS technology and the associated peripherals will pay for itself in one to two years.