CN102166579B - Method for recycling and separating paper, aluminum and plastic packaging boxes - Google Patents

Abstract

The invention provides a method for recycling and separating paper-aluminum-plastic packaging boxes, comprising the steps of: taking paper-aluminum-plastic packaging boxes, dispersing them in a hydraulic disperser, screening and separating pulp fibers for high-value utilization of cellulose, and the remaining It is an aluminum-plastic composite material; after mixing the obtained aluminum-plastic composite material with a separating agent, stir gently until the aluminum and plastic are completely separated, and finally wash the separated aluminum and plastic separately. The separation method of the invention has low cost, high recovery efficiency and no pollution to the environment.

Description

A method for recycling and separating paper-aluminum-plastic packaging boxes

technical field

The invention belongs to the technical field of separation of composite packaging materials, and relates to a method for recycling and separating paper, aluminum and plastic packaging boxes.

Background technique

The paper-aluminum-plastic packaging box represented by Tetra Pak is a high-humidity packaging carton made of paper, aluminum foil and polyethylene plastic, which can be used for liquid food such as milk, juice, soybean milk, coffee, wine, etc. Package. The packaging generally has 6 layers, which can effectively block all factors that affect the deterioration of milk and beverages. Among them, the contents of cardboard, polyethylene plastic and aluminum foil are 73%, 20% and 5% respectively.

There are three main technical solutions for the recycling of traditional paper-aluminum-plastic packaging boxes: (1) Hydraulic recycled pulp technology: the pulp in the paper-aluminum-plastic packaging box is separated to make paper again, and the remaining aluminum-plastic composite Extruded into granules for the manufacture of plastic-aluminum products; (2) Wood-plastic technology: crush and extrude the pulp and plastic contained in paper-aluminum-plastic packaging boxes to make plastic-wood products; (3) Color board technology: The paper-aluminum-plastic packaging box is directly crushed and heat-pressed to make a color board. Although the products produced by these technologies are widely used, the market response and profit margins are still not comparable to the completely separated aluminum and plastic products. Only by completely separating paper, plastic, and aluminum can we maximize the use of materials and save resources, and achieve a higher recycling value.

At present, the pulp recovery method in the paper-aluminum-plastic packaging box is to use a hydropulper to separate the fibers through the shear force of water and the friction between the fibers. The separation methods of the remaining aluminum and plastic mainly include physical and chemical-mechanical methods. (1) Using the different melting points of aluminum and plastic (the melting point of aluminum is 660°C, and the melting point of LDPE is 107-120°C), the plastic is pyrolyzed and gasified, the aluminum foil is recycled, and the gasified plastic is used for power generation. But this method has caused a large amount of waste of plastics. (2) Utilize the property that aluminum and aluminum oxides are soluble in acid and alkali, and dissolve aluminum with acid or alkali, thereby recycling plastics. However, this method has problems such as long reaction time, incomplete separation, and difficulty in extracting aluminum from the solution. (3) Use some acidic organic solvents to penetrate LDPE to reach the joint surface of aluminum and plastic, and dissolve the alumina on the joint surface, so as to achieve the effect of separating aluminum and plastic. The organic acid can be formic acid, acetic acid, propionic acid and butyric acid, but this method is based on the premise of acid consumption, the recovery cost is high, and the separated waste liquid is not easy to handle. (4) Use a single organic solvent (such as benzene, acetone, dichloromethane, etc.) to separate aluminum and plastic. However, experimental studies have found that when single organic solvents such as acetone and methylene chloride are used, it is almost impossible to separate the plastic from the aluminum foil, while when using a single organic solvent such as benzene, LDPE will be directly dissolved, and the plastic cannot be recycled. Therefore, a single organic solvent has defects such as large usage, high cost, and poor separation effect.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for recycling and separating paper, aluminum and plastic packaging boxes, which has low cost, high recycling efficiency and will not pollute the environment.

In order to achieve the above purpose, the present invention provides a method for recycling and separating paper-aluminum-plastic packaging boxes. The paper-aluminum-plastic packaging box is taken out, and after being dispersed in a hydraulic disperser, pulp fibers are screened and separated for high-value utilization of cellulose. The rest is aluminum-plastic composite material; after mixing the obtained aluminum-plastic composite material with a separating agent, stir gently until the aluminum and plastic are completely separated, and finally clean the separated aluminum and plastic separately. Low-concentration separation is adopted, wherein the mass concentration of the slurry is 1% to 5%; after the aluminum-plastic composite material is mixed with the separating agent, ensure that the liquid amount of the separating agent is immersed in the aluminum-plastic material; the aluminum-plastic composite The solid-liquid ratio of the material and the separating agent is 60g/L, and the components and volume percentages of the separating agent are: benzene: 20-80%, absolute ethanol: 10-45%, water: 10-80%, and the The components of the separating agent add up to 100% by volume percentage.

As a preferred embodiment of the present invention, when screening, a slotted screen with a slot width of 0.10-0.15 mm is used, and the mass concentration of the slurry during screening is 0.8-1.0%;

As a preferred embodiment of the present invention, the dispersing treatment conditions of the hydraulic disperser are: rotating speed 500-1000r/min, temperature: 30-50°C, pH value 7-8, and dispersing time 10-20min;

As a preferred embodiment of the present invention, the aluminum-plastic composite material and the separating agent are carried out in a container with a constant temperature of 60°C;

As a preferred embodiment of the present invention, after the aluminum-plastic composite material is separated by a separating agent, when cleaning, it is firstly cleaned with an ethanol solution with a concentration of 50-80% to remove benzene on the aluminum-plastic composite material, and then rinsed with clean water.

The method for recycling and separating the paper-aluminum-plastic packaging box of the present invention has at least the following advantages: the method of the present invention can separate aluminum and plastic separately, has low cost, high recycling efficiency, and does not pollute the environment. In addition, on the basis of fiber recovery and high-value utilization, the present invention uses ethanol and water to properly dilute benzene, and then treats the aluminum-plastic composite, which can effectively swell LDPE, reduce the bonding force between aluminum and plastic, and quickly compound aluminum and plastic. The material is completely separated, and the yield of separated aluminum foil and plastic is very high, reaching more than 95%. The separated waste liquid can also be easily recycled and reused, which shows that this is an effective way to separate and recycle aluminum and plastic.

Detailed ways

The method for the present invention is described in detail below:

Example 1

Cut the paper-aluminum-plastic packaging box into a block size of 40×40mm, and disperse it in a hydraulic disperser with a rotational speed of 500r/m, a pH of 7, a temperature of 40°C, and a mass concentration of the slurry of 1%. 20 minutes, and then use a slotted screen with a slot width of 0.1mm to screen. During screening, the mass concentration of the slurry is 0.8%. The pulp fibers obtained after screening are used for high-value utilization of cellulose, and the rest are aluminum-plastic composite materials. ;Put the obtained aluminum-plastic composite material and separating agent into a container at a constant temperature of 60°C at a solid-to-liquid ratio of 60g/L, ensure that the liquid amount of the separating agent is immersed in the aluminum-plastic material, and stir gently for 3 minutes to completely separate the aluminum. For plastic, the separated aluminum plastic is first cleaned with a 50% ethanol solution to remove benzene on the aluminum plastic, and then rinsed with water.

Through the method, the separation rate of the pulp fiber is as high as 100%, and the yield of the pulp fiber is 95%; the separation rate of aluminum and plastic reaches 100%, the yield of plastic is 95%, and the yield of aluminum is 100%.

The separating agent is composed of 30% benzene, 20% absolute ethanol and 50% water by volume.

Example 2

Cut the paper-aluminum-plastic packaging box into 50×50mm block size, and disperse it in a hydraulic disperser with a rotation speed of 700r/m, a pH of 7, a temperature of 50°C, and a mass concentration of the slurry of 3%, and the dispersing time is 15min, and then screened with a slotted screen with a slot width of 0.13mm. During screening, the mass concentration of the slurry was 0.9%. The pulp fibers obtained after screening were used for high-value utilization of cellulose, and the rest were aluminum-plastic composite materials. ;Put the obtained aluminum-plastic composite material and liquid separating agent into a container with a constant temperature of 60°C at a solid-to-liquid ratio of 60g/L, ensure that the liquid amount of the separating agent is immersed in the aluminum-plastic material, and stir gently for 6 minutes to completely separate To remove the aluminum plastic, the separated aluminum plastic is first cleaned with a 60% ethanol solution to remove the benzene on the aluminum plastic, and then rinsed with water.

Through the method, the separation rate of pulp fiber reaches 100%, and the yield rate of pulp fiber reaches 93%; the separation rate of aluminum and plastic reaches 100%, the yield rate of plastic is 96%, and the yield rate of aluminum is 100%.

The separating agent is composed of 25% benzene, 30% absolute ethanol and 45% water by volume.

Example 3

Cut the paper-aluminum-plastic packaging box into 50×50mm block size, and disperse it in a hydraulic disperser with a rotating speed of 1000r/m, a pH of 8, a temperature of 50°C, and a slurry concentration of 5%. A slotted sieve with a slot width of 0.15mm is used for screening. When screening, the mass concentration of the slurry is 1.0%. The pulp fibers obtained after screening are used for high-value utilization of cellulose, and the rest are aluminum-plastic composite materials; The aluminum-plastic composite material and the liquid separating agent are placed in a container with a constant temperature of 60°C at a solid-liquid ratio of 60g/L to ensure that the liquid amount of the separating agent is immersed in the aluminum-plastic material, and the aluminum-plastic composite material can be completely separated by stirring slightly for 10 minutes. , the separated aluminum plastic is first cleaned with an 80% ethanol solution to remove benzene on the aluminum plastic, and then rinsed with water.

Through the method, the separation rate of the pulp fiber reaches 100%, and the yield of the pulp fiber reaches 92%; the separation rate of aluminum and plastic reaches 100%, the yield of plastic is 93%, and the yield of aluminum is 100%.

The separating agent is composed of 40% benzene, 20% absolute ethanol and 40% water by volume percentage.

The separating agent of the present invention will dissolve plastics of a certain quality after repeated use for a certain number of times, and automatically stratify after standing for a period of time. The benzene layer and the ethanol-water layer were recovered separately. After the plastic layer is heated at 90°C to evaporate the separating agent, the dissolved plastic and organic solvent can be recovered.

In the aluminum-plastic composite material obtained after the paper-aluminum-plastic packaging box of the present invention is screened by a hydraulic disperser, the bonding methods of the aluminum foil and the plastics on both sides are different. One side uses molten polyethylene as the adhesive, and the other side uses Organic adhesive bonding, it is difficult to completely separate aluminum foil and plastic by common separation methods, and the separation purity and yield are also low. After being treated with the separating agent of the present invention, aluminum and plastic can be completely separated.

It is worth noting that: on the basis of fiber recovery and high-value utilization, the method of the present invention uses ethanol and water to properly dilute benzene, and then treats the aluminum-plastic composite, which can effectively swell LDPE, reduce the bonding force between aluminum and plastic, and quickly The aluminum-plastic composite material is completely separated. After separation, the yield of aluminum foil and plastic is very high, reaching more than 95%. The separated waste liquid can also be easily recycled and reused.

In the method of the present invention, the purpose of slight stirring is to make the aluminum-plastic composite material fully contact with the separating agent and prevent the separating agent from delamination. Clean the small amount of benzene on the separated aluminum and plastic with 50-80% ethanol, and finally rinse with water to remove the small amount of ethanol attached to the surface.

The above is only one embodiment of the present invention, not all or the only embodiment. Any equivalent transformation of the technical solution of the present invention adopted by those of ordinary skill in the art by reading the description of the present invention is the right of the present invention. covered by the requirements.

Claims (6)

1. the aluminum-plastic packaged box of paper reclaims separation method, it is characterized in that: get the aluminum-plastic packaged box of paper, after the dispersion treatment, screening is isolated paper pulp fiber and is used for the cellulose higher value application in the waterpower dispersion machine, and remaining is the aluminum composite material; With after release agent mixes, gentle agitation is until isolate aluminium and plastics fully with the aluminum composite material that obtains, the aluminium separated and plastics cleaned respectively to get final product at last; Described waterpower dispersion machine adopts low dense separation, and wherein, the mass concentration of described slurry is 1～5%; Described aluminum composite material guarantees the amount of liquid submergence aluminium plastic material of release agent with after release agent mixes; The solid-to-liquid ratio of described aluminum composite material and release agent is 60g/L, the component of described release agent and percent by volume are: benzene: 20～80%, absolute ethyl alcohol: 10～45%, water: 10～80%, each component of described release agent adds up to 100% according to percent by volume.

2. the aluminum-plastic packaged box of paper as claimed in claim 1 reclaims separation method, it is characterized in that: during screening, adopting seam wide is the slotted screen of 0.10～0.15mm, and the stock quality concentration during screening is 0.8～1.0%.

3. the aluminum-plastic packaged box of paper as claimed in claim 1 reclaims separation method, and it is characterized in that: the dispersion treatment condition of described waterpower dispersion machine is: rotating speed 500～1000r/min, temperature: 30～50 ℃, the pH value is 7～8, and the time of discongesting is 10～20min.

4. the aluminum-plastic packaged box of paper as claimed in claim 1 reclaims separation method, and it is characterized in that: described aluminum composite material and release agent are to carry out in the container of 60 ℃ of constant temperature.

5. the aluminum-plastic packaged box of paper as claimed in claim 1 reclaims separation method, it is characterized in that: described aluminum composite material during cleaning, at first is 50～80% ethanolic solution cleaning with mass concentration after release agent separates, remove the benzene on aluminium and the plastics, and then wash with clear water.

6. the aluminum-plastic packaged box of paper reclaims separation method, it is characterized in that: described is 500～1000r/m with the aluminum-plastic packaged box of paper at rotating speed, the pH value is 7～8, temperature is 30～50 ℃, the mass concentration of slurry is to disperse in 1～5% the waterpower dispersion machine, the time of discongesting is 10～20min, then wide at seam is to screen in the slotted screen of 0.10～0.15mm, when wherein screening, the mass concentration of slurry is 0.8～1.0%, the paper pulp fiber that obtains after the screening is used for the cellulose higher value application, and remaining is the aluminum composite material; The aluminum composite material that obtains and release agent are put into 60 ℃ of constant temperature by the solid-to-liquid ratio of 60g/L container, guarantee the amount of liquid submergence aluminium plastic material of release agent, gentle agitation 3～10min, can isolate aluminium and plastics fully, be that 50～80% ethanolic solution cleans with concentration at first with the aluminium separated and plastics, remove the benzene on aluminium and the plastics, and then wash with clear water; The component of described release agent and percent by volume are: benzene: 20～80%, and absolute ethyl alcohol: 10～45%, water: 10～80%, each component of described release agent adds up to 100% according to percent by volume.