Recovery of aluminum from plastic packages containing aluminum by gasification

Abstract

The standing pouch, a packaging material made of multiple layers of plastic and metal, presents a significant challenge for full recycling. Gasification shows promise as a method to recover aluminum from this type of waste and convert it into energy. This study aims to evaluate the efficiency of gasification in treating aluminum-containing plastic packages, and recovering aluminum while identifying the optimal combinations of temperature and equivalence ratio (ER) to achieve the best outcomes. The study achieved a conversion rate of 43.06 wt% to 69.42 wt% of the original waste mass into syngas, with aluminum recovery rates ranging from 35.2 % to 65.3 %. Temperature and ER alterations affected the product distribution, aluminum recovery rate, and aluminum partitioning in the products. The results indicated that the combination of 700 °C, ER = 0.4 would provide the largest amount of syngas about 69.42 %, which is the main product of the gasification process, and therefore, this combination is the most optimal for syngas-yielding purposes. Under the reclaiming aluminum is more prioritized, the combination of 800 °C, ER = 0.6 would be the most optimal condition, the majority of Al in fuel was found in char and fly ash were 67.5 % and 4.81 %, respectively. The study focused on the partitioning of aluminum during the gasification process, which was observed to mainly exist in the form of Al₂O₃(s), with gaseous species including AlCl₃(g), AlH(g), and Al₂O(g) due to their medium volatility. As the ER increased, the amount of O₂ also increased, leading to more Al₂O₃(s) formation. In conclusion, this research provides a foundation for further exploration of gasification as a means of energy conversion and metal recovery.

Keywords: Aluminum recovery; Gasification; Metal partitioning; Plastic.