Rapid transformation of the metal-polymer laminated packaging materials into ceramic carbide reinforced Al-alloy

Abstract

Aluminium is a widely used metal in combination with polymers in flexible packaging materials applications. Cast-off polymer-metal multilayer food packaging materials (PMM-FPM) have been recycled in this study by two different techniques. First, a single-stage smelting at 900 °C as a traditional smelting recycling process was adopted for the waste packaging materials along with the laminated polymers and some leftover organic residues. In the second route of recycling the raw PMM-FPM was initially thermally disengaged at 550 °C for 20 min in a controlled environment followed by the rapid transformation (RT) process in an arc furnace at a very high temperature with an artificial deficiency of the oxidizing agents to avoid any kind of material loss by oxidation. A brief comparison of the microstructures, crystal structures, mechanical and the surface properties of the recycled Al by both techniques have established the existence of a ceramic carbide (Al4C3) reinforcement in the Al matrix recycled by the rapid transformation process where another recycled Al (Al-900) from the single-stage smelting contains some graphitic carbonaceous materials in a non-uniform pattern. In situ formation of the Al4C3 in the Al eventually produced a ceramic reinforced alloy. This innovative recycling process yields reinforced alloy of enhanced physical, mechanical, microstructural, and surface properties with no loss of metallic content and comparable for advanced industrial applications.