Plastic recycling technology refers to the science and technology of recycling plastics, including melt regeneration, thermal cracking, energy recovery, chemical raw material recovery and other methods.

Main text

The world's synthetic resin production has reached 200 million tons, and the problem of dealing with a large amount of post-consumer plastics has become a hot topic in today's global environmental protection. At present, there are several ways to deal with post-consumer plastics: 1. Landfill; 2. Incineration; 3. Composting; 4. Recycling; 5. Using degradable plastics.

Section 1 Plastic Recycling Methods

Plastic recycling methods include: melt regeneration, thermal cracking, energy recovery, chemical raw material recovery and other methods.

(1) Melt regeneration Melt regeneration is a method of reheating waste plastics and plasticizing them for use. According to the source of waste plastics, this method can be divided into two categories: one is the recycling of clean waste plastics recovered from the scraps of resin factories and processing plants; the other is the recycling of various plastic products mixed together after use. The former is called simple recycling, which can produce plastic products with better performance; the latter is called composite recycling, which can generally only produce plastic products with relatively poor performance requirements, and the recycling process is relatively complicated.

(2) Thermal cracking The thermal cracking method is a method of thermally cracking selected waste plastics to produce fuel oil and fuel gas.

(3) Energy recovery Energy recovery is a method of utilizing the heat generated when waste plastics are burned.

(4) Recycling chemical raw materials. Some types of plastics can be hydrolyzed to obtain the raw monomers for synthesis by adding polyurethane. This is a method of recycling waste plastics by chemically decomposing them into chemical raw materials.

(5) Others. In addition to the above-mentioned methods of recycling waste plastics, there are various methods of utilizing waste plastics, such as crushing waste polystyrene foam plastics and mixing them into soil to improve soil water retention, air permeability and drainage, or mixing them with cement as fillers to make lightweight concrete, or adding adhesives to press them into mat materials, etc.

Recycling of plastics and treatment of plastic solid waste Using petroleum and coal as raw materials to produce plastics to replace natural polymer materials has gone through a difficult journey. A whole generation of outstanding chemists have worked hard to achieve the excellent physical and chemical properties and durability of plastics. With its light weight, durability, beauty and low price, plastics have replaced a large number of traditional packaging materials and promoted a revolution in the packaging industry. However, it is unexpected that it is precisely these excellent properties of plastics that have produced a large amount of durable and incorruptible plastic waste. A large amount of plastic packaging discarded after use has become a major scourge that harms the environment. The main reason is that these plastic wastes are difficult to handle and cannot be decomposed and turned into dust. In the existing urban solid waste, the proportion of plastics has reached 15%-20%, and most of them are disposable plastic packaging products. The treatment of plastic waste is no longer just a problem for the plastic industry, but has become a widespread concern of the international community of public hazards.

In order to meet the needs of protecting the earth's environment, the world's plastic processing industry has developed many new environmental protection technologies. In terms of resource conservation, the focus is on improving product aging resistance, extending product life, multifunctionality, and product design; in terms of resource recycling, the focus is on studying efficient sorting of plastic waste, separation technology, efficient melting recycling technology, chemical recycling technology, completely biodegradable materials, water-soluble materials, and edible films; in terms of volume reduction technology, the focus is on studying waste plastic compression and volume reduction technology, film bagging container technology, and on the premise of ensuring application performance, the focus is on making the product thinner as much as possible; in terms of the development of CFC substitutes, the focus is on studying carbon dioxide foaming technology; in terms of substitute research, the focus is on developing PVC and PVDC substitutes.

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