Untersuchungen zur Dispersion und ihren Auswirkungen beim Übergang aus der Nutzungsphase in das Recycling : Betrachtungen am Beispiel von Leichtgutanteilen von Waschmaschinen in Shredderprozessen
Schäfer, Tobias; Pretz, Thomas (Thesis advisor)
Aachen : Publikationsserver der RWTH Aachen University (2004)
Dissertation / PhD Thesis
Aachen, Techn. Hochsch., Diss., 2004
Recycling processes that take place after the end of the useful lifetime of a product generate secondary raw materials to substitute primary ones. This is a step towards sustainable development. Recycling processes proceed during a short period compared to the lifetime of a product of up to several decades. Recycling involves costs, specific to processing and materials. The comparison of recycling and utilization of a product leads to an investigation of the influence of the intended use on the cost of recycling. To analyse this relationship and to identify cost relevant aspects, different kinds of recycling are explained and characterized by their mass relevance. The connection of recycling and product use is based on dispersion. Dispersion means the distribution of materials within the environment and can be analysed according to the three categories material, time and place which can also interact. The mass stream of copper has been selected to analyse the quantitative aspects of dispersion. The total of all copper considered for four different product applications is made available for the recycling process as the so-called copper deposit. For a more detailed analysis of the product specific and dispersion related costs of recycling, attention is focussed on the waste sector of electric and electronic equipment and here, in special, on white goods. Washing machines have been experimentally prepared for recycling purposes. The common recycling method for washing machines is the use of car shredders. The shredding technique combined with an airflow separation is explained and experimentally applied on the laboratory scale of a technical school. The shredding process combined with a magnetic separation creates three output fractions: iron products, the non-ferrous metal fraction and the shredder light fraction (SLF). The cost structure of recycling is described by the determination of the SLF fraction as a function of the age of the washing machines and by the composition of the product masses. A special SLF indicator is defined. The total mixture of raw materials in the shredder - old cars, electrical goods and further scrap - is of importance for environmental and economic reasons. Different legislative directives become relevant for the shredding process; laws for end-of-life-vehicles concern also electrical products. The definition of processing and recycling quotas by law influences the choice of recycling techniques and input materials and proves to be cost effective. Calculations and analyses of recycling situations are presented and point out the relevance of the SLF indicator.