Development of new contamination-tolerant aluminum alloys from end-user scrap
EVAEND develops new aluminum alloys that meet high technical requirements even when using contaminated post-consumer scrap. This is complemented by innovative cleaning technologies and digital process support. As a result, high-quality aluminum recycling becomes more economical and flexible.
The recycling of aluminium is one of the key factors in reducing greenhouse gases and raw material consumption in the production of initial material. Recycling saves more than 90% in energy and CO2 emissions. Additional savings arise from the reduced need of raw materials and the elimination of disposal. The recycling rate for aluminium in Germany is already at 90% and cannot be significantly increased. It is therefore necessary to further improve aluminium recycling processes. The increasing demands on materials require significant preparation of the raw material from post-consumer scrap. This scrap must be cleaned, sorted and processed in preparatory smelting, which is a costly process. The energy required for separation alone can be up to 0.2 MWh per ton. In addition, there is an accumulation effect of alloying elements such as silicon, magnesium, copper, iron, manganese, chromium and others in the source scrap. These alloying elements must therefore be repeatedly removed from the melts. This is done either by dilution with primary aluminium or by depletion using chemical methods such as the removal of magnesium by chlorine cleaning.
Simplified application of post-consumer scrap would further enhance the positive effects on resource conservation. For this reason, this project gains to develop a family of aluminium alloys that, on the one hand, meet the high demands of the material and, on the other hand, are easy to use for users of unsorted aluminium scrap.
The consortium is pursuing a three-step approach to achieve this.
- The development of process steps to convert any initial melt from cleaned but unsorted post consumer scrap into a base melt with the desired composition. Calphad simulations and thermodynamic calculations are used to identify chemical compounds andthe process steps needed to precipitate undesireble elements and compounds.
- Developing a group of aluminium alloys that, through the addition of a few alloying elements from the base melt, result in a material with the desired properties. Here, too, digital material development methods are used. These are supported, verified and improved by extensive material analysis and testing of different process routes.
- Develop software that enables users to determine a suitable process for producing the desired material based solely on the chemical composition of the scrap melt and the desired material parameters.
It is essential to carry out comprehensive material analyses and evolution of multiple process routes to achieve the project goal. This is supplemented by checking the mechanical characteristics to determine the limits of use. This project considers both known methods, such as the addition of fluxes, and new approaches that may result from the thermophysical conditions in the melt. Ultimately, the new group of aluminium alloys will not be suitable for all applications. It will therefore be geared towards common requirements such as corrosion resistance or strength, making it suitable for a broad range of applications. In addition to considering the new innovative material, the resulting waste materials from precipitation are also being investigated and evaluated for possible recycling, e.g. as alloying elements.
Fehrmannn Materials will contribute its expertise in the field of digitally based material development to the consortium and, as an industrial user, will play a key role in defining the requirements profile. Hereon, as a qualified materials research institution, will provide extensive experience in the field of material characterization. The Foundry Technology group within the Intitute of Metallurgy at TU Clausthal will conduct the melting experiments on the various scrap samples in this project and continuously refine the process
