Fraunhofer ILT and Cronimet Ferroleg develop laser scrap metal sorter

25 Jan 2021

German Government-funded “PLUS” project yields sensor that boosts efficiency of metal recycling.

The Fraunhofer Institute for Laser Technology (ILT) and Karlsruhe, Germany-based metal scrap and recycling group Cronimet Ferroleg have together developed a laser-based sorting process for metal scrap. Their aim is to improve industry access to such raw materials. The development is part of the German BMBF-funded PLUS project.

A new sensor they have developed makes the recycling of metallic raw materials more efficient than previously possible, says ILT. The EU project REVaMP goes one step further: in this project, Fraunhofer ILT experts have also been contributing their expertise in the field of materials analysis at the European level since January 2020, making a significant international contribution to securing a resource-efficient supply of raw materials.

The partners stated, “Germany as a production location and, thus, our social prosperity depends largely on the availability of metallic raw materials such as chromium, nickel, copper and cobalt. As their global demand is rising, however, these metals are becoming increasingly scarce commodities. Since there is a shortage of mineral resources, recycling raw materials plays a decisive role in curbing the shortage and is the most important source of metallic raw materials in Germany and Europe.

There are clear advantages of recycling: used metal scrap that can no longer be used, such as pipes, sheet metal, tools, old cables, electrical and electronic scrap and old parts from households or demolition, can be melted down, sorted by metal or alloy, and reused with virtually no loss of quality.

Due to the high value of the materials, the process offers a means of paying for itself – and produces significantly less CO₂ than conventional processes. In fact, say the partners, the new method renders the expensive, technically complex conventional extraction of mineral resources unnecessary.

Both the price and availability of metal scrap and its recycling rate depend on numerous mutually dependent factors. These include fluctuating prices on the primary market, the life cycle of products and their collection rate, losses in the process, technical recyclability and the value of the alloy in question.

Improved yield

The new sensor technology makes the detection and sorting of alloys in metal scrap much faster and more accurate. In 2020, a pilot plant was put into operation at the Cronimet-Ferroleg site in Karlsruhe and has performed “remarkably well,” according to the partners. Among other things, it is designed to process high-speed steels, or HSS for short.

“HSS tools contain valuable alloying elements such as cobalt and can be found in any hardware store. For example, in drills or milling heads,” said Dr. Cord Fricke-Begemann, who is responsible for materials analysis at Fraunhofer ILT and led the PLUS project with the support of PhD student Fredrik Schreckenberg.

Conventional processes are often limited to the laborious manual measurement of a few alloys. On the other hand, laser-induced breakdown spectroscopy, developed at Fraunhofer ILT and used in PLUS, is a technology that can identify more than 20 special alloys even in small scrap parts – automatically, quickly and without contact.

“In a short time, we can process more scrap and achieve higher grade purity,” said Fricke-Begemann. “In this way, we are building an important bridge between research and industry.”

As part of the EU project “Retrofitting Equipment for Efficient Use of Variable Feedstock in Metal Making Processes” (REVaMP), which was launched in 2020, Fraunhofer ILT is now contributing its expertise in the field of material analysis at the European level. The project, which is scheduled to run for three and a half years, is supported by an international alliance of companies and research institutes from Spain, Poland and Germany.

“The goal is to put the knowledge gathered in the PLUS project on a universal basis, regardless of the alloys involved,” said Fricke-Begemann. “We want to build a sensor that can be installed in existing industrial plants to make the recycling process fundamentally more efficient.”