SONTHOFEN – Kajaanin Romu Oy operates one of Finland’s most advanced plants for recycling scrap in the town of Kajaani, located approximately 500 km northeast of Helsinki.
The company recently commissioned a BHS-Sonthofen plant for processing automotive shredder residue (ASR) fine fractions of particle sizes between 0 and 30 mm. It separates the feed material abundant with valuable metals into ‘light’ and ‘heavy’ fractions in a single pass. This allows the plant operators to economically produce fractions that can be sold profitably. Moreover, the plant significantly reduces the cost of material disposal at landfills.
Experience with operating shredders in the context of recycling has proven time and again that heavy non-ferrous fractions of material left over after shredding and processing large automotive, electrical or electronic scrap components still hold value. A metric ton can contain up to 20 grams of gold and up to 300 grams of silver, as well as platinum and other precious and non-ferrous metals.
Operators report that they are able to earn about EUR 3,000 per metric ton just from selling the heavy fraction of non-ferrous metals. BHS has taken improved fine fraction processing even further by integrating secondary cleaning of metals into the processing stage. This allows Finnish operator Kajaanin Romu Oy to unlock the value of reusable materials present in the ASR fine fraction. The system delivers a throughput of around 10 metric tons per hour.
At the end of the process, even the non-ferrous metal fractions are cleanly separated in silos. This includes heavy ones such as copper, gold and silver as well as light fractions such as aluminum. Presently, the proportion of salable non-ferrous metals amounts to about five to seven percent of the processed volume.
BHS-Sonthofen ASR systems do not only process fine fractions from automotive shredders. They are also suitable for processing waste incineration plant slag and electronics scrap. This means that recycling companies can adapt their product portfolio to meet increasing requirements: The higher the proportion of electronic components and platinum in vehicles and electronic devices, the greater the volume of valuable substances that can be extracted for reuse.
The technology in detail
The plant installed at Kajaanin Romu is fed fine fractions with a particle size of under 30 mm from the automotive shredder. In other words, it processes fractions that could not be used prior to introducing this system. The Rotor Impact Mill of type RPMV 1513 – a system uniquely offered by BHS-Sonthofen – crushes the material and separates it. In doing so, it works selectively, finely crushing brittle materials such as mineral substances, glass and castings and separating composites. Elastic materials such as rubber, on the other hand, remain intact.
The metals can be reclaimed since the Rotor Impact Mill shapes the pliable metals into balls. This is necessary in order for non-ferrous metals to be cleanly separated from other materials in the downstream process. The material, which is often long and flat when inserted into the mill, has to be compact and as round as possible to enable separation of the non-ferrous metal pieces.
Following this step, the material passes through a hopper into a screening machine that separates it into three fractions of 0 to 3, 3 to 6, and 6 to 12 mm. Each of these is separated into ‘heavy’ and ‘light’ through density separation. The heavy material that contains the metallic components is further separated into magnetic and non-magnetic metallic fractions using magnetic separators.
In the final processing stage, non-ferrous metals are separated into heavy (e.g., copper, gold and silver) and light (e.g., aluminum) fractions.
Moreover, the plant also generates a light fraction that primarily consists of plastic parts. This fraction is suitable for thermal utilization and does not need to be disposed of at landfills.