Understand the waste plastics cleaning technology and reject secondary pollution!

Plastic products vary in size and size. After these products are discarded, they must be broken into pieces of a certain size by some means to be recycled or further molded into various recycled products. Of course, there are many advantages to the recycling of waste plastics, such as convenient packaging, transportation, storage, cleaning, etc.

1, the broken link

Crushing technology

From the different divisions of technical principles, there are four basic forms of fragmentation. They are:

1 crushing technology

The material is pulverized into small pieces by the relative compressive force of the material. It is suitable for large-sized waste plastic products and is not suitable for soft plastics. The mode of action includes the pressing action of two relatively moving metal plates, the rolling action of two opposite rotating rolls, and the eccentric rotation of the inner cone in the outer cone.

2 crushing technology

The material is crushed by an external impact force and is suitable for brittle materials. Its action mode includes the impact of external hard objects (such as hammering with a hammer), the high-speed impact of the material itself and the fixed hard steel plate, and the impact between the materials.

3 Grinding technology

The material is crushed into fine particles by being crushed between different shapes of abrasive bodies, and is suitable for bulk materials.

4 cutting technology

The material is broken into small pieces or fragments under the action of cutting, puncture, shredding, etc. of the sharp edge of the blade, and is suitable for tough materials, films, sheets and soft products.

The above broken form is shown in Figure 1 -

Figure 1 The basic form of fragmentation

Selection of crushing equipment

The choice of crushing equipment depends mainly on the type and shape of the material being crushed and the degree of crushing required. Different materials have different properties, and the crushing equipment used may be different.

For example, rigid PVC, PS, plexiglass, phenolic resin, urea-formaldehyde resin, polyester resin and other materials are brittle plastics, which are brittle and brittle. They are subjected to compressive or impacting forces and are easily broken into small pieces. Plastics are suitable for compression or impact pulverizing equipment; while PE, PP, PA and ABS have good toughness at room temperature, shear crushing equipment is suitable; for some low temperature brittle materials, such as soft PVC is suitable for low temperature crushing equipment.

2, cleaning process

The role and classification of the cleaning process

In the recycling process, except for some production wastes, such as waste, waste, scrap, etc. from injection molding and extrusion processing plants, which can be directly crushed and recycled, most of the waste plastics will be contaminated. After being cleaned, it can be recycled. The purpose of cleaning is to remove impurities and prepare for subsequent processing.

At present, the plastic recycling enterprises mostly use the traditional wet cleaning method to clean the waste plastics. The cleaning medium is a mixture of clean water or detergent. Cleaning methods are divided into manual cleaning and mechanical cleaning. Due to the low efficiency of manual cleaning, the use range of manual cleaning has been gradually reduced, and mechanical cleaning with high degree of automation has become the mainstream. With the advancement of technology, waterless cleaning technology has gradually played a role on the stage.

Waste plastic cleaning technology

1 intermittent wet cleaning

First, put the waste plastic into a sink and rinse it, and use a plastic mixing machine to remove the loose dirt adhering to the plastic surface, such as sand, mud, etc., to sink it into the bottom of the tank; if there are many wood chips and paper, it can be loaded. Further purification in the sedimentation tank with special pump; for the adhesion of solid dirt, such as printing ink, adhesive-coated paper label, you can manually pick out the larger one, and then put it into the hot alkali after being crushed by plastic crusher. Soak for a period of time in the aqueous solution tank, and then rub them against each other by mechanical agitation to remove the dirt. Finally, the washed pulverized waste plastic is sent to a centrifuge for drying, and dried by two steps of hot air to a residual moisture of ≤0.5%.

2 continuous wet cleaning

The waste plastic is sent to the plastic pulverizer by the conveyor belt, coarsely pulverized, and then sent to the large separation section to sink the sand and the like into the bottom of the water, and is sent away at regular intervals. The floating material is conveyed into the wet mill through the conveying roller, and then enters into the sedimentation tank. All the things heavier than the water are separated, and even the smallest particles are no exception, achieving the best cleaning effect.

3 bottles of hot wash

The hot wash of the bottle piece includes the steps of floating washing and rinsing. The hot wash and float wash unit can effectively remove the caps, bottle rings, oil and beverages left in the bottles, external glue and other impurities; the rinse unit can remove the residual agent after the heat wash, and make the surface of the bottle The PH value tends to be neutral, ensuring the cleanliness and transparency of the bottle.

4 waterless cleaning

The waterless cleaning of waste plastics is a piece of debris of a certain thickness and broken to a certain size, using physical forces such as friction, grinding, collision, etc., so that the dirt adhering to the sheet is separated and dispersed in the air medium, and separated by a dust collector and a cyclone. The machine is dusted and separated to obtain clean plastic chips.

There is no waste water generation in waterless cleaning, and secondary pollution is greatly reduced. It is the key area of ​​relevant research at present, and its technology, process and equipment are in the exploration stage.

3. Classification of waste plastic pollution sources

At present, plastics are used in almost all walks of life, and also cause plastic products and different substances to contact. Different types and sources of waste plastics cause different pollutions, mainly in the following categories:

1 Suspended matter pollution: waste plastics are mainly contacted or packaged with cotton yarn, chemical fiber, quartz sand, cement, calcium carbonate, etc.;

2 Organic pollution: Waste plastics are mainly contacted or packaged with food, feed, beverages, etc.;

3 Grease pollution: waste plastics are mainly contacted or packaged with greases;

4 lysate pollution: waste plastics are mainly contacted or packaged with sodium chloride, soda ash, etc.;

5 color pollution: waste plastics are mainly contacted or packaged with dyes and Pigments;

6 PH value pollution: waste plastics are mainly contacted or packaged with strong acid and strong alkaline substances;

7 Microbial contamination: Waste plastics are mainly derived from disposable medical equipment;

8 Toxic substance contamination: Waste plastics are mainly exposed to or packaged with toxic and hazardous substances.

It is strictly forbidden for processing enterprises of 5-8 types of materials to purchase such waste plastics. Such waste plastics recycling enterprises should be equipped with perfect water treatment facilities and labor protection for workers. Some pollutants will cause great harm to the human body after contact!

In actual production, there are mainly 1-4 types of waste plastics, and there are no toxic and harmful substances. The washed water can be discharged after simple treatment. Simple processing investment is small, mainly using precipitation method.

4. Secondary pollution in crushing and cleaning

The pulverization and cleaning of waste plastics is very serious for environmental pollution, mainly in wastewater and waste gas. The dust generated during the crushing process, the irritating odor emitted by the mixed washing liquid in the cleaning is the source of the exhaust gas; the wastewater is mainly derived from the wastewater eliminated during the cleaning process and the contaminated mixed washing liquid.

Some irresponsible plastic products manufacturers directly discharge waste water, waste gas and waste generated in the process to nearby residential areas, paddy fields and river courses, causing serious pollution to surrounding soil, water and air. At the same time, it seriously affects people's lives and physical health.

The environmental protection inspection, the waste plastics industry suffered heavy losses, over 70% of the enterprises failed to pass the review, was ordered to shut down the rectification, most enterprises because the waste water, waste gas treatment is not in place.

Waste plastic recycling itself is an energy-saving and environmentally friendly, green economy. However, blind pursuit of interests, the process of secondary pollution is more serious than the waste plastic itself, then the waste plastic recycling industry will lose its meaning. Entrepreneurs who are willing to work in this industry will join hands to boycott and reject secondary pollution, and promote the sustainable and harmonious development of this industry!

5, domestic partial broken cleaning equipment manufacturers

1. Guangzhou Lianguan Machinery Co., Ltd.

2. Greenwell Machinery (Zhangjiagang) Co., Ltd.

3. Jiangsu Bell Machinery Group

4. Evian (Shanghai) Machinery Co., Ltd.

5. Austria Erima Plastic Recycling Engineering Machinery Co., Ltd.

6.Zhejiang Baolv Special Environmental Protection Technology Engineering Co., Ltd.

7. Dongguan Licai Hardware & Plastic Products Co., Ltd.

8. Zhangjiagang Aisruite Machinery Co., Ltd.

9. Jiangsu Lianguan Machinery Co., Ltd.

10. Zhangjiagang Beach Machinery Co., Ltd.

6, some domestic environmental protection equipment manufacturers

1. Zhucheng Guangsheng Environmental Protection Equipment Co., Ltd.

2. Shandong Shuiheng Environmental Protection Engineering Co., Ltd.

3.Hangzhou Jianhao Environmental Protection Equipment Co., Ltd.

4. Guangdong Zhishun Chemical Environmental Protection Equipment Co., Ltd.

I. Introduction
Papermaking dry strengthen agent is our company`s new and self-developed products that using imported raw materials. Its mechanism of action is: Dry Strength Agent use polymer mesh structure to increase hydrogen bonding number in the mutual area of fiber to fiber. Dry strength agents in the combination area of long-chain polymers can be deformed, thus increasing the bond toughness. It could improve paper strength by the bridging ability formed by chemical function to make fibers and fibers have "implicated"

II. Technical indicators

III. Function

     The dry strength agent is not only a good enhancement, but it also has a higher enhancement effect in waste papers with more fine fiber filler. The use of our dry strength agent can improve paper quality, and it also significantly increase production efficiency, reduce costs and increase economic efficiency.

IV. Method of Application and Notes

1. When diluted with clean water, the dilution multiples of our product is generally about 15 to 30 times. After the product was stirred sufficiently, add uniformly to the slurry in an amount of 5 ~ 10 kg / ton.

2. Adding position that selected could have a full contact with the slurry. Generally choose ingredients pool, high box or import pump.

3. Use a plastic or stainless steel as the material for products storage, dilution tank, piping etc.. Iron-based material will produce corrosion and thickening phenomenon will occur.

4. Do not mix with Other Chemicals.

V. Packing

      1000 kg barrels, or according to user requirements.

Dry Strength Agent

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Shandong Tiancheng Chemical Co., Ltd. , https://www.akdchemical.nl