Sorting technology for plastic packaging waste

Plastic packaging waste can be separated from other garbage by artificial or mechanical (gravity method), and then it can be directly identified, burn identification, specific gravity identification, solvent separation, wind screening, electrostatic separation, cryogenic grinding and other methods.
1. Intuitive identification of sorting technology The following methods can be used for the classification of waste plastics in a small quantity: First, the metal, glass, string and other debris and serious pollution of waste plastics removed; Second, the agricultural film, packaging film, foam Plastics and plastic bottles are categorized; third, they are classified according to the color shade of the products; fourthly, the commonly used polyvinyl chloride, polystyrene, polyethylene, polypropylene and other plastics are used for simple methods such as visual inspection, feel, specific gravity, and burning. classification.
2. Density sorting technology Various plastics have different densities. Different kinds of plastics are placed in a specific solution, and the plastics are classified and identified according to the ups and downs of the plastics in the solution. Because plastics are not wettable, they need to be pretreated with surfactants, wetted and then sorted. Commonly used identification plastic solutions are water, saturated salt solution, alcohol solution and calcium chloride solution.
3. The solution sorting technology uses a variety of plastics in the organic solution to achieve the separation of waste plastics according to the difference in solubility. The method is to add waste plastic chips to a specific solvent, control different temperatures, and selectively dissolve and sort various plastics. This technology has less solvent loss, and the recovered polymer can be reused after being heated and granulated, and its performance is good.
4. Wind screening technology When the amount of waste is large and there is a lot of debris, wind filtration technology can be used. In this method, the crushed waste plastic is put into the re-screening chamber from above, air is injected from the horizontal direction, and the weight of the plastic and the difference in air resistance are selected.
5. Electrostatic Separation Technology Electrostatic separation technology originates from the dry separation method. It is characterized by the separation of particulate matter with a diameter of less than 8 mm regardless of its density. Its size and shape do not affect the separation, and it has low energy consumption and a large amount of processing.