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Compaction of aluminium foil and its effect on oxidation and recycling yield

Abstract

One of the problems when recycling aluminium is its oxidation and consequent
metal loss. This is especially critical for the thin sheet/foil materials used for
food packaging applications. Compacting the scrap into briquettes may partly reduce
such losses in addition to facilitate transport and storage. Shredded aluminium materials
of different thicknesses (15-300 microns) were compacted into cylindrical briquettes
of 4 cm diameter, each weighting 20 g by uniaxial pressure or moderate-pressuretorsion.
A sub-set of briquettes and chips was subsequently oxidized at 650 C, while
a sub-set was left untreated. Finally, all samples were re-melted under molten protective
salt-flux. Compacting reduced the specific oxidation during the heat-treatment
and promoted the coalescence and yield for the heat-treated materials. Both effects
were most significant for the thinnest foil in the study (15 microns). The material thickness
influenced the porosity and surface roughness of the resultant briquette, as well
as the pressure required to reach a given bulk density.
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Category

Academic article

Language

English

Author(s)

  • Alicia Vallejo-Olivares
  • Harald Philipson
  • Mertol Gökelma
  • Hans Jørgen Roven
  • Trond Furu
  • Anne Kvithyld
  • Gabriella Tranell

Affiliation

  • SINTEF Industry / Metal Production and Processing
  • Norwegian University of Science and Technology
  • Norsk Hydro ASA

Year

2021

Published in

The Minerals, Metals & Materials Series

ISSN

2367-1181

Page(s)

735 - 741

View this publication at Norwegian Research Information Repository