Economic and environmental evaluation of end-of-life aerospace aluminum options using optimization methods

The benefits of recycling have long been understood and the conspicuous energy savings of secondary aluminum production have caused aluminum recycling to increase. Obsolete aircraft are a valuable source of aluminum scrap and recent efforts to fortify the aerospace aluminum recycling infrastructure have drawn attention to the potential of sophisticated sorting methods to maximize the economic gain of using aerospace scrap in secondary production. The aim of this research was to use linear optimization to assess the economic viability of sorting technologies for enabling wrought products in general and aerospace alloys in particular to be recycled back to high value applications. A chance-constrained model was used to select the alloys that consumed the largest quantity of aerospace alloys in their production, thereby establishing a strategic portfolio of finished goods. Ten of the fifteen alloys in the portfolio were of the 2xxx and 7xxx alloy series that are standard in the production of aerospace components. An aerospace end-of-life case study was performed in which cases varied by their input scrap streams, each having a compositional uncertainty associated with the different degrees of sorting that methods currently in use and technologies in development can achieve. The chance-constrained model calculated the production cost for each case and determined that when aerospace components were identified to the precision of individual alloys, the production cost was 20.87% lower than the cost for primary production. Using automatically sorted scrap input yielded a production cost that was 5.34% lower than the cost of primary production.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Chen, Emily, S.B. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Randolph E. Kirchain, Jr.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/42998

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/42998