Thermal De-coating Pre-treatment for Loose or Compacted Aluminum Scrap and Consequences for Salt-Flux Recycling

Abstract In aluminum recycling, thermal de-coating pre-treatments remove moisture and organic contamination before re-melting. If the scrap is compacted into bales or briquettes treatment re-melting processes, less surface area exposed to oxidation in contact with air. However, compaction may also limit efficiency of process. this study, coated sheets were thermally de-coated at varied temperatures durations. Observations changes coating thickness, mass, color, composition revealed a maximum close 75% wt due remaining oxide residues. The relationship between was investigated by treating loose shreddings (chips) various densities. three methods: uniaxial, moderate-pressure torsion (MPT), MPT 450 °C (Hot MPT); calculated from mass loss. Subsequently, samples re-melted under salt-flux compared another set which without pre-treatment. results showed that significantly promotes coalescence chips uniaxially, up similar coalescences than initially uncoated samples. Thermally briquettes, more densely compacted, led de-coating, subsequently lower coalescences. analysis material residues did not affect composition, while prevented Mg loss for materials. Graphical