Limits, Losses, and Environmental Impacts of Recycling of Ferrous Materials Embedded in End-of-Life Vehicles

Printer-friendly version

Hybrid Analysis with Explicit Consideration of Scrap Quality

Shinichiro Nakamura

Professor of Industrial Ecology

Faculty of Political Science and Economics, Waseda University, Tokyo, Japan

Ecotopia Science Institute, Nagoya University, Nagoya, Japan

Hosts: Faye Duchin, Economics, x2038, and Peter Fox, Tetherless World Constellation, x4862

Wednesday, November 16, 2011
Winslow Building, Room 1140
Refreshments: 3:30 pm-4:00 pm
Colloquia: 4:00pm-5:30 pm


In contrast to polymers such as plastics or textiles, the material quality of which is doomed to degrade over successive recycling, metals can be subjected to unlimited cycles of recycling. In reality, however, metals are seldom used in isolation, but in combination with different metal species as alloys and/or parts. This can result in mixing of different metal species in the end of life (EoL) phase and in qualitative degradation of secondary metal materials.
Notwithstanding its vital importance for sustainable use of metal resources, issues surrounding the quality of secondary metal materials have seldom been the subject of studies in Industrial Ecology in general, and in material flow analysis (MFA) in particular. This presentation addresses quality issues of iron and steel (I&S) scrap recovered from end of life vehicles (ELV). We focus on the effects on materials/energy requirements and greenhouse gas (GHG) emissions of the quality and dilution losses that result from mixing of ferrous materials in the EoL phase. Our method is based on a hybrid input-output model (WIO-MFA).

We use the body of data that consist of Japanese IO data with more than 400 sectors augmented by information about detailed flow of I&S, the material composition of automobile parts and components, and information about the types of treatment (dismantling for reuse/recycling, and shredding) of the parts and components are also included.

The results indicate, among other things, that the possibility of using secondary ferrous materials in a closed loop (cars to cars) is limited, and that the avoidance of quality and dilution losses in the EoL process can result in a significant reduction in the requirements for primary iron and energy (and the emissions of GHG) associated with car production.