Recycling of post-consumer multilayer Tetra Pak® packaging with the Selective Dissolution-Precipitation process

Abstract

Tetra Pak cartons, i.e. multilayer packaging consisting of paper, low density polyethylene (LDPE) and aluminium, are widely used as aseptic packages in the food and beverage industry. Paper can be easily recovered from this type of post-consumer beverage cartons (PCBCs) by the pulp industry. The remaining LDPE/aluminium by-product, however, cannot be easily separated to its constituents so currently it is mostly downcycled or used for energy recovery. The aim of this work is to develop an effective process that separates and recovers LDPE and aluminium of high purity and good quality from Tetra Pak cartons. To this purpose, following paper recovery by hydropulping, LDPE and aluminium are separated using a selective dissolution-precipitation (SDP) process. The recovered LDPE is characterized by FTIR spectroscopy, thermogravimetric analysis (TGA), differential scanning (DSC) and melt flow rate (MFR) measurements. The findings reveal that the SDP separation process is an effective method to recover LDPE and aluminium from PCBCs.