Development of recycling concepts for special-purpose aluminium materials

In order to counter the worldwide diminution of resources, a product was to be developed that can be ideally recycled after its service life. However, recovery of metal materials from special-purpose aluminium materials is difficult using conventional recycling methods. The project participants research the options for metal recovery by examining a variety of materials and methods.  



Increasing consumption of finite resources makes recycling necessary to facilitate their reuse. Recovery of metals, particularly aluminium, from metal compound materials, aluminium foams or special alloys is difficult because the metal constituents cannot be recovered without losses in quality. Increased use of special-purpose materials is an additional obstacle to recycling.

The project participants research the options for metal recycling by examining numerous different materials. The project results provide incentives for the development of new recycling concepts with the lowest-possible degree of loss. Furthermore, the options for integration with conventional recycling methods are researched.


  • Metal matrix composites (MMC) can be broken down into their metal constituents and ceramic substrate structure through melting. The metal yield can be improved by using centrifuges during the remelting process.
  • Adding molten salts during remelting improves conversion of the metal particles to the salt phase.
  • Metal recovery from MMC materials with Al2O3 reinforcement proved efficient after addition of molten salts. Very high yields of > 90% were achievable.
  • Recycling of aluminium foams is also possible through remelting with the addition of CaF as a molten salt. However, care must be taken that the aluminium melt does not contain too much Ti and Li.
  • Examination of Al-Li recycling showed that Na and Ka from the molten salts accumulate in the aluminium. Also, only unprofitable yields could be achieved.
  • From an economic point of view, the quantity and type of molten salt added needs to be chosen optimally.
  • The metals can be recovered from the salt slag by means of leaching.

Project Participants

Implementing Institution

RWTH Aachen - Metallurgische Prozesstechnik und Metallrecycling (IME)

Cooperation partner

VAW Aluminium AG

Hydro Aluminium Deutschland GmbH

More Project Informations

Project title:  Entwicklung von Recyclingkonzepten für Aluminium-Sonderwerkstoffe

Project number:  01RW0116A

Project period:  2009 - 2012

Project region:  Germany (North Rhine-Westphalia)

Project contact:

Herr Prof. Dr. Ing. Dr. h.c. Friedrich

This email address is being protected from spambots. You need JavaScript enabled to view it.

+49 (0) 241 80 95850

+49 (0) 241 80 92154

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Source: German National Library of Science and Technology Hannover (TIB)