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The recycling of a solid residue made from polyethylene and aluminum foil in food brick packaging Rsd (Pet-Al), continues to be a challenge. Despite the fact that previous studies proposed green solutions for the recycling of the Pet-Al composite, the handicaps linked to the increase of the cost of the reagents involved in the recycling mechanism, the complexity of the steps, resulting in products with a critical aspect, really reflect a problem. This article involves chemical treatment by adding a strong base NaOH or KOH as the dissolving reagent, followed by the addition of the strong acid HCl. The birth of a neutral environment promotes the recovery of aluminum salts as well as sodium (or potassium). The released H2, polyethylene and cardboard are also products regenerated by this recycling.

This study aims to develop a mathematical model that can explain the regeneration process mechanism of the aluminum which is in the packaging of food bricks (the Pet-Al residue Rsd(Pet-Al) is a laminated foil residue made from polyethylene and aluminum foil) as a raw material in alkaline solution and evaluate that model based on the experimental data. In fact, the literature shows that a symmetrical diffusion of the reagent occurs through the two sides of large bare surfaces, this is true when both surfaces of the solid are naked. In our case, the Pet-Al residue suggests another mode of attack seeing that both of aluminium surfaces are covered with polyethylene. For that, a new Edge Shrinking model called “Aymen Edge Model” was invented. The process mechanism that occurs involves the reactant diffusion step and the chemical reactions step; those steps run simultaneously. The concentration of free hydroxyls OH− in the solution compared to the reference solution, [OH-]solution - [OH-]reference = f(t), gives an idea of the different stages observed during of the consumed hydroxyls evolution. The SEM micrographs resulting, after a basic treatment, with concentration from 1M to 10M at a temperature ranging from 20 to 80 °C, proves that the attack is done by the edges and also confirm the obtaining salts.