Politecnico di Torino - Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

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LDPE and aluminum recovery from packagings

AluminumCO2 and aminesPackaging recyclePolyethyleneSwitchable solvents

Introduction

The invention relates to an innovative treatment of polylaminated food packaging residues, after paper removal. In particular it provides the complete separation and recovering of pure LDPE and not-oxidized aluminum, using totally recyclable and low cost switchable solvents, triggered by the addition and removal of carbon dioxide.

Technical features

Chips of polylaminated LDPE-Al-LDPE residues, are treated at 90°C with a tertiary amine solvent. Filtration provides pure aluminium flakes. The residual solution is bubbled with gaseous carbon dioxide causing a polarity switch of the solvent that allows separation and recovery of pure LDPE. Finally, CO2 removal from the residual liquid provides the tertiary amine that is recycled into the process.

Possible Applications

  • Recycling of food packaging residues;
  • Recovery of aluminium from polylaminated material;
  • Recovery of LDPE from polylaminated material;
  • Utilization of waste material from paper-recycling plants.

Advantages

  • Good yield and good properties of materials recovered;
  • Closed loop with complete recovery of the reactants;
  • Mild process, room pressures and low temperatures;
  • Low cost reagents recycling and easy realization of the procedure;
  • Recycling of raw materials for food packaging.