TG/DTA-FTIR study on total resource recovery from Tetra Pak waste by pyrolysis under a CO2 environment

Pyrolysis of Tetra Pak waste under CO2 was investigated using a thermogravimetric/differential thermal analyser coupled with a Fourier transform infrared spectrometer. Experimental results showed that cellulose was decomposed between 270 and 390 degrees C, leading to the formation of aldehydes, ketones, carboxylic acids and levoglucosan. Thermal cracking of polyethylene occurred between 440 and 530 degrees C and the main products were aliphatic hydrocarbons. CO can be produced by the gasification of pyrolytic char by CO2 at temperatures ranging from 860-970 degrees C. Aluminium (Al) foil remained in a "thin layer shape" despite melting above 660 degrees C. CaO was generated from the decomposition of CaCO3 used as a paper filler at 722 degrees C. The reaction between CaO and the CO2 atmosphere during the cooling process led to the formation of new CaCO3 which was the main component of ash after gasification and was easy to separate from Al foil.