Recycling aluminum shavings is an ELF project involving two teacher-researchers and several groups of students. It is currently continuing in collaboration with the LAMPA laboratory and a thesis.
How can aluminum machining chips be recycled? This is the goal set by Mariem Ben Saada and Bruno Lavisse, professors and researchers on campus.
A major challenge
"Producing 1kg of virgin aluminum consumes 14.6kg of CO2 equivalent," explains Bruno Lavisse. By comparison, it takes 2 to 3 kg for steel. It is therefore a major challenge to maximize the proportion of recycled alloy in raw aluminum, as it is used extensively in industry, particularly to lighten structures in construction and aeronautics."
Optimizing chip manufacturing parameters
Three groups of students therefore devoted their projects to this topic, with the themes "Recycling of machining chips for the manufacture of foundry parts," "Study of the recyclability of aluminum machining chips," and "Recycling of chips by compaction."
The aim is to optimize the parameters for generating these chips (machining) and conditioning (compacting) in order to recover the chips through casting and obtain mechanical strengths close to those of virgin aluminum ingots.
To do this, the students compacted the chips, carried out castings and measured the loss rate (chip mass vs. final ingot mass), then performed mechanical and structural tests.
Finally, they modified the machining and compaction parameters to improve the process.
Start a collaboration with the LAMPA laboratory
"Today, we are also starting a collaboration with the LAMPA laboratory in Metz to make a comparison using hot extrusion instead of remelting," explains Bruno Lavisse.
Another avenue for optimization is replacing oil-water lubrication with cryogenic assistance to obtain dry chips that do not require a cleaning phase before remelting.
Finally, a thesis is being started on optimizing the recycling of aluminum chips, which is relevant to machining and remelting parameters, but also to cleaning these chips with, for example, liquid or supercritical CO2.
