Improving jigging results of non-ferrous car scrap by application of an intermediate layer

In the processing of car scrap the 4–16 mm non-ferrous fraction can be separated according to density by means of wet jigging. The light product mainly consists of aluminium, glass and stone, the heavy product consists of metals, such as copper, lead, brass, stainless steel etc. Turbulence and irregularities in the feed composition can result in poor grade and recovery of the products. It has been investigated whether the grade and recovery will improve by adding a continuously recycled intermediate fraction. During the jigging process this fraction should form a distinct layer between the heavy and light non-ferrous fractions, enhancing the separation result. The intermediate fraction could, for example by means of a magnetic separation, be recovered from both products and recirculated. The optimum properties of the intermediate fraction in terms of size, shape and density of the material were been established for the case of a 4–16 mm non-ferrous fraction.