The Structural Secrets of Aluminum-Plastic Film
Aluminum-plastic film packaging bags resemble a sandwich: an outer protective plastic film (approximately 40μm), a middle aluminum foil (6-12μm), and an inner heat-sealed plastic layer. The thickness of the aluminum layer determines the aluminum content. Aluminum foil used in ordinary food packaging is approximately 9μm thick, accounting for 5%-10% of the total material weight. Based on this, the theoretical aluminum content in one pound (500 grams) of aluminum-plastic film is approximately 25-50 grams.
The Gap Between Theory and Practice
Under laboratory conditions, approximately 45 grams of aluminum (99% purity) can be extracted from one pound of aluminum-plastic film through chemical dissolution. However, in actual recycling:
Mechanical separation leaves 15%-20% aluminum residue on the plastic.
High-temperature melting may result in an oxidation loss of 5%-8%.
Impurity contamination reduces the effective recovery rate to around 70%.
Ultimately, the actual amount of aluminum obtainable is approximately 18-35 grams.
Economic Considerations for Recycling
Currently, the price of recycled aluminum is approximately 15 yuan/kg. The value of aluminum extracted from 1 catties of aluminum-plastic film is approximately 0.3-0.5 yuan. The processing costs need to be balanced:
Chemical Method: Processing cost approximately 8 yuan per kg
Physical Method: High equipment investment but low long-term cost
Mixed waste sorting will increase losses by 10%-15%.
