Large-scale, closed-loop recycling plants have undeniable advantages, but their high recycling costs make them suitable only for areas with a large amount of waste polystyrene, especially expanded polystyrene. For general waste polystyrene foam, large-scale centralized collection is difficult, so investing in large-scale recycling plants or workshops currently faces certain difficulties in China. Smaller, simpler recycling equipment is more suitable for China's current situation.

　　Compared with various domestically and internationally available equipment for recycling polystyrene resin, the performance of recycled resin is inevitably lower than that of new resin. After being subjected to a certain recycling temperature, the molecular chains will inevitably undergo some chain breakage and degradation, and some additives will also degrade or volatilize due to the influence of higher temperatures, resulting in a decrease in the performance of the recycled resin. Recycled materials inevitably contain impurities that cannot be completely removed, so recycled materials can only be used in small amounts mixed with new materials. If recycled materials are used entirely, only low-grade products can be produced. Furthermore, from a hygiene perspective, they can only be used to produce non-food contact products. To address the drawback of reduced performance in recycled materials, particularly brittleness, some manufacturers usually add additives to improve this aspect. For plastic processing plants, this method is relatively easy to implement, requiring no additional equipment and incurring minimal costs. However, this method has limited effectiveness in improving the performance of recycled materials. To enhance the usability of recycled polystyrene, it can be blended and modified with other high-toughness polymer materials. However, this method presents certain technical difficulties and is not feasible for all plastic product manufacturers. If a specialized factory and equipment were to undertake this task, it would undoubtedly lead to increased costs, a situation currently not feasible in China.

　　For general plastic processing enterprises, the usual practice is to clean, crush, melt, extrude, and granulate the waste plastic generated in their own factory, then mix a small amount into new materials for use. This is the simplest recycling method. Its advantages are low cost and minimal need for additional equipment. If polystyrene foam blocks are collected from society, this method can also be used, but the soiled parts must first be removed or cleaned. For polystyrene foam containers used as tableware, they can be cleaned and recycled using the above method. However, it is actually very difficult to completely clean them; they will inevitably contain a certain amount of oil stains, food, and juice, affecting the performance of the regenerated resin. In such cases, thermal decomposition to recover styrene or oil is preferable. In the past, thermal decomposition of waste polystyrene foam to recover styrene was generally characterized by low styrene yields. However, recent research has shown that adding certain metal catalysts can improve styrene yields. The products obtained from thermal decomposition, after processes such as distillation, can yield high-purity styrene, and the remaining residue can be used as a waterproof material for buildings, achieving almost complete utilization. Recycling styrene also requires specialized recycling equipment, mainly pyrolysis reaction equipment. If equipment is specifically set up for recycling, the amount of waste polystyrene foam to be recycled must be very large; otherwise, the cost will be high and uneconomical. If old equipment from chemical plants can be modified, equipment investment can be significantly reduced. Many units in China are developing catalytic pyrolysis technology for styrene recovery, and some have achieved good results, with high yields and styrene content exceeding 99%, and relatively cost-effective equipment investment.

　　The method of using waste polystyrene foam to produce various protective paints and adhesives after solvent melting is generally relatively simple and low-cost. It is more suitable for the scattered use and disposal of polystyrene foam in China and can be recycled and processed locally as needed.

　　With the development of China's raw material industry, the manufacturing industry will also experience greater development, and the amount of discarded plastic will also increase significantly, posing a greater threat to the environment. Therefore, recycling efforts must progress rapidly. With economic development, the use and demand for polystyrene foam will also increase, leading to a corresponding increase in discarded polystyrene foam. If the recycling of waste polystyrene foam is not properly handled, it will not only pollute the environment and waste resources but also cause social criticism and affect the development of the plastics industry.

　　Many countries and regions around the world have banned the use of plastic products in certain areas to reduce the environmental harm caused by plastic waste. Italy was among the first to enact such regulations, completely banning the use of plastic bags in 1991. While Germany and Switzerland have not completely banned them, they are gradually reducing the use of plastics in packaging. In the United States, half of the original plastic packaging has been replaced with new paper packaging. To prevent the increase in plastic volume, Japan has banned or reduced the use of plastic packaging in many areas and has only allowed reduced production of existing polystyrene beverage cups and boxes, without allowing expansion or increased production capacity. The bans on plastic packaging currently adopted by various countries are measures taken in response to environmental pollution caused by poor plastic waste recycling. In earlier years, the development and application of plastics received widespread praise from various countries and parties, and humanity enjoyed the many conveniences brought about by the development of plastics. However, in recent years, when plastic waste recycling and processing have not kept pace, it has been subjected to criticism, seemingly becoming a culprit in environmental damage.

　　In recent years, the amount of plastic waste generated in industrialized countries has been astonishing. In 1990, North America's plastic waste reached 11.8 Mt, accounting for 49% of that year's plastic production, while Europe's plastic waste reached 13.6 Mt, accounting for 46% of that year's plastic production. This shows the enormous amount of plastic waste. To reduce plastic waste and promote the reuse of recycled plastics, industrialized countries such as those in Europe and America have successively formulated regulations and policies on the recycling and application of recycled plastics. These regulations and policies stipulate the recycling rate of waste materials and the processing methods used to meet these requirements.

　　Following the reform and opening up, China's plastics industry has experienced rapid economic development. In 1995, the national plastic output reached 6.2 Mt, with plastics used for packaging accounting for about 30%, approximately 1.8 Mt. Among these, films, bags, ropes, bottles, boxes, and cups with very short lifecycles accounted for more than 50% of plastic packaging. These products are quickly discarded, and the accumulated discarded plastics have caused considerable environmental damage. Fortunately, many enlightened individuals and units across the country have conducted research on the reuse of waste plastics, and some have achieved successful experiences. For example, waste polystyrene foam can now be completely recycled and reused. The current difficulty lies in the recycling of polystyrene extruded foam fast-food containers, mainly because the used containers have food and juice adhering to them, which are difficult to remove. If recycled directly, these contaminants will obviously enter the recycled material, making it unusable. We can learn from the cleaning methods of other materials, first crushing or cutting them into 20mm square pieces, then cleaning them with detergent and water and drying them. After cleaning to remove contaminants, other recycling processes can be used for recycling, which is entirely feasible. Cleaning waste plastics is not difficult; conventional washing machines or simple washing machines can be used. Ordinary detergents or special detergents can be used for washing.

　　From the various methods mentioned above, it is not difficult to recycle polystyrene foam. It can be said that the existing methods and equipment are completely usable for recycling, but many waste polystyrene foams are still not fully recycled. For example, large pieces of polystyrene foam are easy to recycle, while scattered pieces are not; polystyrene foam discarded inside factories is easy to recycle, but the lunch boxes scattered along the railway lines are not easy to recycle. In order to protect the environment and fully recycle waste polystyrene foam, the state can formulate some regulations to restrict the use of polystyrene foam in certain aspects to reduce waste, and can also formulate recycling regulations. In addition, the state should encourage and support the recycling of waste polystyrene plastic, and give enterprises some preferential policies to mobilize their enthusiasm.