Finland – A rotor impact mill supplied by Germany’s BHS-Sonthofen has helped a Finnish recycler convert ‘previously unusable’ automotive shredder residue (ASR) into a valuable secondary resource.
Kajaanin Romu Oy’s plant at Kajaani some 500 km north east of Helsinki separates ASR fines with particle sizes of 30 mm and below into light and heavy fractions in a single pass, producing output streams that ‘can be sold profitably’ while reducing the company’s landfill costs.
The RPMV 1513 rotor impact mill crushes and separates in a selective manner, finely crushing brittle materials such as minerals, glass and castings, and separating composites, whereas elastic materials like rubber remain intact. The impact mill shapes the pliable metals into balls; material has to be compact and as round as possible to enable separation of the non-ferrous metal fragments in the downstream process.
Material passes through a hopper into a screening machine that creates three fractions of 0 to 3 mm, 3 to 6 mm, and 6 to 12 mm; heavy and light fractions are obtained from each via density separation, with the heavy material that contains metallic components also subjected to magnetic separation.
BHS has integrated secondary cleaning of metals into the processing stage through a system that delivers a throughput of around 10 tonnes per hour. ‘At the end of the process, even the non-ferrous metal fractions are cleanly separated in silos,’ BHS-Sonthofen points out. ‘This includes heavy ones such as copper, gold and silver as well as light fractions such as aluminium.’
Saleable non-ferrous metals account for approximately 5-7% of the processed volume while the plant also generates a light fraction consisting primarily of plastics suitable for thermal utilisation.
BHS-Sonthofen’s ASR systems can also process waste incineration plant slag and electronics scrap.