RECYCLING AND RECOVERING FINE PARTICLES FROM AUTO SHREDDING RESIDUE (ASR/SR) TO CONSERVE RAW MATERIALS AND PROTECT ENVIRONMENT

摘要

Shredding or Auto Shredding Residue (SR/ASR) is a complex heterogeneous product of shreddingrnplants consists of mixed materials including small particles of ferrous and non-ferrous metals,rndifferent plastics, glass, stones, wood, ceramics, etc.rnSince new environmental and technical legislations have been introduced, for example the newrnEU legislation for recycling ELVs, there have been challenges in recycling through shredding plantsrnworldwide. For example, in order to achieve the goals for the recycling rate for end of life vehiclesrn(ELVs) in accordance with the new EU legislation, 80 per cent of the shredding residues must bernrecycled which is not an easy task to overcome, especially for fine SRs with particle sizes finer thanrn8 mm.rnA comprehensive study was completed to review the physical processes for treating shreddingrnresidues worldwide and attempts were made to characterise a shredding residue sample from arnSwedish recycling plant and to investigate possibilities for recovering ferrous and nonferrous metalsrnas well as an organic fraction (plastics) from the residue.rnThe characterization of the residue sample indicated it consists of more than 20 per cent liberatedrnmetals, 30 per cent of glass, and more than 45 per cent of organic fractions. However, there arernmetals in association with organic and other components that are not liberated.rnFurther, it was concluded that comminution of the sample is beneficial in separating differentrnfractions. Electrical separation technique, as the most cost effective separation technique, wasrnperformed to separate conductors, ie metals, from non-conductors. Dry magnetic separation was alsornconducted to separate ferrous metals from non-ferrous and other components within the conductorrnfraction.rnThe results indicated to be possible to recover 30 per cent of the fine residue, P <8 mm, as the qualityrnmetal fraction. The distribution for the ferrous and nonferrous metals is approximately 50 per cent,rnwhich can be achieved by dry magnetic separation. Investigation indicated the separation would berninefficient without comminuting the feed. The results showed promising, taking into account thatrnthere is no need for water (dry process) and thereby no need for water treatment and water recycling.rnFurthermore, the energy consumption is minimal.