Polyethylene processing: equipment, technology. Recycling and Disposal of X-Ray Film Recycling of Polyethylene Film
Removal, processing and disposal of waste from 1 to 5 hazard class
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Why is neglect of containers dangerous and how important is polyethylene recycling for the environment? In our life, polyethylene is present as a packaging container, but despite its narrow specialization, it is widespread everywhere. Almost every house has a package with packages that we collect from the principles of economy. But the trouble is, it turns out that the better the raw material, the more difficult it is to dispose of it and the longer the period of its decomposition itself.
The relevance of processing
Recycling of polyethylene raw materials is an important cost item for the city, as the material is characterized by incredible stability. He is not afraid of water, alkali, salt solutions. Polyethylene is not afraid even of organic and inorganic acids. It can be noted that these are good qualities, but they can turn into a number of problems.
First of all, the ecological situation causes concern - according to approximate estimates, the decomposition of polyethylene takes up to 300 years. If a plain plastic bag ends up in a landfill in total mass household waste, it greatly complicates the processing process. Over time, this package undergoes thermal aging, gradually decomposing under the influence of sun rays, heat and oxygen. In the course of destruction, a harmless package releases harmful chemical substances into soil and water.
Alas, it is not possible to limit the production of plastics and polyethylene, but it is possible to rationally organize the entire workflow. Waste polyethylene, in fact, is a versatile material. Recycling of polyethylene without exaggeration can be called the new life of raw materials. Man is required to create and improve ways to collect and process raw materials in order to make the process cyclical. Polyethylene waste may well become everyday items.
Processing companies
AT last years the number of organizations processing this raw material is steadily growing. Moreover, the point is not only in environmental problems, but also in the prospects for the development of such a business. Polyethylene can be an excellent base for creating plastic panels, garbage containers, all kinds of household containers. There is a certain scope for the imagination of entrepreneurs, although, of course, secondary polyethylene products involve some limitations.
The recycling of film and bags does not cause difficulties, since the structure of the materials used does not change for the most part, but the quality of the recycled raw materials decreases, and, accordingly, the scope of further application narrows.
Workflow features
There are several recycling cycles plastic bags, films. The first cycle has almost no effect on the decrease in consumer characteristics of new products. But each subsequent cycle makes its own “negative contribution”, making raw materials suitable only for the production of special materials.
According to existing technologies, six stages of polyethylene waste processing can be distinguished:
- First comes the collection of raw materials: films, bottles, other household waste. Waste sorting can be done by manual or mechanical labor. If household waste during collection is divided into waste paper, glass, paper, PET, then it is possible to reduce the amount of garbage that needs to be disposed of by a third.
- The collected raw materials are sent to washing machines. This stage is necessary in order to get rid of dirt, foreign objects and paper. If raw materials are directly handed over to collection points, then the receiver can check the condition of the film, bottles, waste paper in order to increase or decrease the price offered for them.
- Next, the collected raw materials are crushed, for which crushing plants are used.
- In case moisture or random solid impurities remain in the raw material, the centrifuge process is carried out.
- Now the material is sent to the drying chamber, where heat treatment also takes place.
- Job completed and material ready for recycling. It can be used to make universal products: plastic film, bags, packaging, pipes.
Work in detail
And now let's try to take a closer look at the process of processing polyethylene into granules, because before that the process was considered only schematically. Of course, the right equipment is required for the job.
Well-established work is possible with:
- washing machine
- crushing plant
- centrifuges
- drying plant
- agglomerator
- granulator
- extruder
In production, the presence of a conveyor or pneumatic conveyor will be relevant, which will allow the process to be fully automated.
At home, it is almost impossible to establish an uninterrupted process for obtaining recycled polyethylene, but you can lay the foundation for promising business. First of all, you can declare the process of collecting raw materials, since without it such work is in principle impossible. Manual sorting of household waste will cost less than mechanical sorting, but you will have to start with a small amount of raw materials used.
Self-processing of the film allows you to get a dense waterproof fabric with a waterproofing function. The work process itself is simple - a piece of film must be laid between two parts of the fabric and ironed with an electric iron. The output is a three-layer composite material, as the film melts and penetrates into the layers of the fabric. With your own hands, you can get a composite material based on film, fabric and aluminum foil. The algorithm of operation is the same except for the fact that one layer of fabric is replaced by foil. Film, fabric and foil material is an excellent heat insulator. With the help of cross-linked polyethylene, many people equip a warm floor in the house.
For more benefit
Agglomerator - a device capable of processing film and bottles. Due to the temperature effect, an agglomerate is obtained - baked lumps from former bottles and films. The agglomerate can be sold already at this stage or go further and process it into pellets.
The polyethylene granulator allows you to increase the company's income from the collection and sale of secondary raw materials. The result is a product that technically outperforms its “powdery or flake counterparts in the shop” due to its small volume (and, accordingly, lower packaging and transportation costs), high flowability, minimization of losses and dust formation, lower risk of destruction and photoaging.
Why does an enterprise need an extruder? Just with its help you can get a unique material - polyethylene low pressure. The extruder starts working after the agglomerator has his say and turns the result of collection and processing into slurry. Now the molten mass of plastic goes through the forming hole, where it melts and creates threads that cool under water and are cut into small pieces. At the output, a HDPE granule is ready.
At low pressure
Low density polyethylene is widely used all over the world. It is an organic compound that resembles white wax. Recycled low-density polyethylene is obtained through the collection and recycling of bottles and pipes.
This material is not afraid of frost or chemicals. It does not feel shock and is not a current conductor. It should be added that this material is waterproof and does not react with alkalis, acids and salt solutions. HDPE decomposes under the action of nitric acid (50%), chlorine and fluorine.
How this product can be useful
- Based on HDPE, accessories for swimming pools are made.
- It is used in the process of 3D printers.
- Such material is actual for work in the conditions of chemical and electric influence.
- HDPE is good for creating anti-corrosion coating, food containers, bottles and collecting water connections.
- In sports facilities, HDPE is used for the production of gymnastic hoops.
- In restaurants, HDPE is a future plastic bag, plastic set or container. The HDPE bag rustles and wrinkles, so it is used for the so-called "T-shirts".
- Pyrotechnics makers use HDPE to make their work more spectacular.
Outcome
The processing of polyethylene raw materials into granules makes it possible to significantly reduce the amount of garbage in urban landfills. Remember that polyethylene and plastic almost do not decompose. Meanwhile, on the basis of PET, you can make successful business. Don't throw away things that might come in handy later. Even a simple package, bottle, film - can be useful for business.
Polyethylene recycling is one of the few recycling technologies that provides a solution environmental problem waste, and can bring good profits.
The problem of pollution of the planet with polyethylene is becoming more serious every year. The use of this material is so widespread that it is found in almost every field. human life. Difficulties in disposal and a long period of decomposition threaten our planet. To solve the problem, technologies for processing and recycling the substance are being developed. This is a great way to get rid of the huge amount of garbage in landfills around major cities and build a profitable production on this basis. The introduction of this method on a global scale is a chance to defeat an ecological catastrophe.
Relevance of polyethylene processing
It is not easy to dispose of this material - the structure and composition of polyethylene provide resistance to various chemical factors which is what makes it so popular. In terms of use, these qualities are exactly what you need. However, it is these same properties that lead to the impact of waste on the environment.
The decomposition of polyethylene takes about 300 years. A dangerous factor is also the fact that, when decomposed, polyethylene objects are capable of releasing dangerous substances into the biosphere. chemical elements that pollute the air, soil, groundwater. In sum, this action affects the state environment and public health.
If this material has such amazing properties and is stored for several hundred years, the question arises, why not take advantage of these qualities of waste. Modern technology allows for recycling polyethylene waste at such a level that the material becomes usable again. This is both a way to save on new materials and a solution to the problem of environmental pollution.
For the smooth and continuous functioning of the processing system, the condition for collecting raw materials and the availability of the necessary equipment is necessary. Subsequent processing will give waste new life as everyday household items.
The number of enterprises involved in the processing of polyethylene waste naturally increases every year - this is facilitated by the relevance and demand for this service. The low cost of the source material and the wide possibilities for the production of goods for which demand does not fall are the key advantages of such a business.
An important point. The use of products made from recycled polyethylene should be included on the packaging of the product, while in terms of quality secondary product inferior to virgin polyethylene. This fact should be considered.
How is the processing of raw materials?
Waste is processed in several successive steps:
- collection of raw materials;
- sorting;
- primary processing;
- grinding;
- processing in a centrifuge;
- the effect of temperature;
- the use of material for the production of products.
The collection of raw materials and their sorting is the beginning of the process. At this stage, the waste is divided into categories that correspond to the type of raw material. Sorting can be done manually or using mechanized devices.
Sorted waste must be cleaned of dirt, parts from foreign material. Raw materials are cleaned in special washing machines. Some collectors of raw materials themselves carry out this procedure, increasing the price of it.
Grinding of purified and prepared raw materials is carried out in special machines, using crushing. The next processing step is centrifugation. This relieves the material of moisture, impurities. After grinding, heat treatment of the material follows.
The raw material is ready for recycling and the production of items from it.
Necessary equipment for polyethylene processing
For a complete and high-quality recycling process, the following equipment is used:
- washing machine;
- waste shredder;
- centrifuge;
- installation for heat treatment;
- agglomerator - to reduce the volume of raw materials;
- granulator;
- extruder - to form a homogeneous raw material, using temperature.
Automation of the process is carried out by using a pipeline - this speeds up the process and allows you to control it in stages.
The use of an agglomerator is one of the ways to increase the efficiency and economy of processing. The output is a commercial product - an agglomerate.
The principle of operation of the agglomerator for polyethylene processing, see the video:
The use of an extruder makes it possible to obtain low-pressure polyethylene, which is resistant to physical and chemical factors.
Extruders are also used for processing raw materials (agglomerate) into a homogeneous melt with giving it a certain shape.
Every year, millions of plastic bags are used and thrown away in Moscow. It turns out that some of them are successfully processed. Today we will go to such an enterprise and find out how polyethylene is prepared for reuse.
The Moscow region company "Expert Vtor" does not process all types of plastic bags, but only film, bags, bags, defective stretch film production (the so-called shrink film) and LDPE.
LDPE is high pressure polyethylene or, as it is also called, low density polyethylene. LDPE waste can be generated during direct production polyethylene film. A lot of waste - in stores (packaging of bottles, boxes, boxes), glass factories (from packaging of bottles, cans), distilleries and breweries (from packaging of containers or finished products).
Stretch film is a linear high-pressure polyethylene (LDPE). It can stretch a lot. Due to this property, as well as increased resistance to punctures and tearing, stretch film is used for packaging various goods, in particular on pallets (pallets). Stretch film waste is mainly generated and accumulated in warehouses of any value, at customs terminals, in logistics centers, etc.
Popular T-shirt bags made of HDPE (low pressure polyethylene) and “biodegradable” bags, which can be found, for example, in the “Azbuka Vkusa”, are not recycled by the company. Polypropylene film, PVC film, air bubble film, polyamide film, LDPE+PP, LDPE+PA multi-layer films, as well as double-sided two-color films are also not suitable. Film contaminated with oils, fats, food waste and pesticides.
The collected polyethylene first enters the warehouse. Up to 100 tons of film waste can be stored here, naturally in pressed form. At the first stage, the raw materials are carefully sorted. The stretch is separated from the LDPE, the types of films that are not processed by the enterprise's capacities are discarded.
After sorting, packages of a certain color are put into a crusher. In it, on V-shaped knives (this type is also called “dovetail”), the film is crushed to particles of uniform size. The knives are powered by an electric motor.
From the crusher, through the pneumatic conveyor, the so-called "crushed" gets into the sink. In it, with the addition of special cleaning solutions, the "crushed" is cleaned of dust and other non-plastic inclusions.
The next stage of processing is agglomeration. In it, the so-called "cooking" takes place. The operator loads clean "crushed" into the working chamber through the loading window.
The raw material enters the rotating rotor along the guides, is crushed by knives and due to friction against the body and between themselves is heated to the temperature of plasticization. In this case, the entire volume of loaded raw materials becomes similar to a mushy mass.
When the material becomes homogeneous, "shock" water is added to it, as a result of which the material is rapidly cooled and sintered into separate small balls. irregular shape. For some more time, the agglomerate is dried at natural ambient temperature and unloaded into prepared containers to go to The final stage. The cooking process itself lasts from 5 to 10 minutes.
The process of granulation can be compared to scrolling minced meat through a meat grinder. Agglomerate, which we received at the previous stage, is loaded into the extruder hopper.
It is called so because the production of granules is based on the extrusion method - forcing the molten mass through a forming hole.
In general, the "mince" from the boiled bags is melted under the action of heaters and pressure created by a rotating screw. The polymer melt is forced through a filter into a rotating extruder head. So-called threads are already coming out of it. To cool them, they are passed through a water hose, and then into knives, where they are cut into homogeneous granules.
The granules are packaged in clean polypropylene bags, approximately 50 kg each. special conditions storage is not required, but it is desirable that it be a dry room. The resulting granules, depending on the composition and color, are sold. Natural color stretch granule goes to the production of secondary stretch.
The natural color LDPE granule is used for the production of secondary shrink or technical film. Colored LDPE granules are mainly used for the production of garbage bags.
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For some reason, many people have the opinion that polyethylene is suitable only for the manufacture of packaging products. Actually it is not. Polyethylene is used in different areas human activity and is a universal material. Recycling of polyethylene can be carried out several times. A profitable occupation is the purchase of polyethylene waste. Recycling companies work closely with businesses. In replenishment raw material base the population is actively involved.
The basis for all types of polyethylene is one chemical monomer. However, finished products in their qualities and properties are very different from each other. The reason lies in the fact that macromolecules have different geometric shapes and the ability to form crystals.
There are three types of polyethylene, which differ in the way they polymerize.
High pressure polyethylene is produced at a temperature of 180°C and a pressure of 1500-3000 atmospheres. This method of production makes it possible to obtain a product of low density, rather soft and elastic. High pressure polyethylene contains branched macromolecules.
Medium pressure polyethylene is obtained at a temperature of 120-150 ° C and a pressure of 30-40 atmospheres. The process requires a diluent and metal oxide catalysts.
Low pressure polyethylene is obtained by polymerization with an organic solvent. The temperature should be less than 80 ° C, and the pressure should be low, about 5 atmospheres. An organometallic complex is used as a catalyst. The processes involve an ionic mechanism.
Polyethylene, obtained using low or medium pressure, has a linear structure of molecules, a high degree crystallization, is a hard material. Polyethylene is a frost-resistant material, it can also be used at temperatures down to -60 ° C. There are grades that retain useful properties at even lower temperatures. Limit hydrocarbon, it is not affected by aggressive media and organic liquids.
In industry, polyethylenes are produced in the form of granules, sheets and blocks. Further, by casting under very high pressure, the so-called extrusion - softened polymers are squeezed out through the nozzles of the Spitz machine, and various products are made from the material by further blowing.
Polyethylene is intended for the production of seamless pipes, insulation of electrical wires and film, which is widely used for product packaging. Partitions, greenhouses for Agriculture, buckets, basins, bottles.
Polyethylene has dielectric properties, which leads to its use as an insulating material for cables in television, radar, telephone lines. It is for these reasons that it is so important to recycle polyethylene.
For this reason, a huge amount of used film accumulates every year, which does not decompose for a long time. As a result, this can lead to ecological disaster. Therefore, the used material must be properly disposed of.
Our company carries out the processing and disposal of film in Moscow and the Moscow region, thanks to which the Natural resources and received secondary raw materials for the production of new products.
How is x-ray film disposed of?
X-ray film accumulated in medical institutions is disposed of only by a professional. This is a rather complicated process that requires compliance with safety rules.
X-ray film recycling technology:
- electrolysis of chemicals;
- filtration to recover silver;
- obtaining a polymer base.
This procedure is environmentally friendly. To carry it out, it is used latest equipment allowing material to be processed.