Four feasible methods for recycling the hottest wa

2022-09-22
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Four feasible methods for recycling waste refrigerator insulation materials

release date: Source: China Plastics browse times: 5171 copyright and disclaimer

core tip: rigid polyurethane foam is widely used as refrigerator insulation material because of its accessibility, ease of use and good thermal insulation. The insulation material in the refrigerator accounts for about 10% of the total weight of the refrigerator. At present, the scrap volume of refrigerators is increasing at an alarming rate, but the treatment and disposal methods of rigid polyurethane foam are mainly stacking, landfill and incineration, resulting in land waste and air pollution, so the need for its resource reuse is particularly urgent

[China Packaging News] rigid polyurethane foams are widely used as insulation materials for refrigerators because of their accessibility, ease of use and good thermal insulation. The insulation materials in refrigerators account for about 10% of the total weight of refrigerators. At present, the scrap volume of refrigerators is increasing at an alarming rate, but the treatment and disposal methods of rigid polyurethane foam are mainly stacking, landfill and incineration, resulting in land waste and air pollution, so the need for its resource reuse is particularly urgent

generally speaking, there are three main methods for the recovery of waste rigid polyurethane foam: combustion recovery heat energy method, physical recovery method, and chemical recovery method

combustion and heat recovery method

polyurethane can produce a lot of heat energy during combustion, so it is often used as fuel together with municipal solid waste for incineration treatment

however, polyurethane will produce toxic gases if it is not completely burned during incineration. Cause pollution. If the combustion efficiency is improved and the back-end exhaust gas treatment is done well through corresponding technologies, the advantages of this treatment method are also very significant, and the treatment effect is relatively fast

tcl Aobo (Tianjin) Environmental Protection Development Co., Ltd. uses the method of combustion to recover heat energy to treat the refrigerator polyurethane insulation materials disassembled by the company. They have adopted the international advanced mechanized and automatic production process equipment, and established the RDF (garbage derived combustion type: acceleration and speed smooth intersection point frequency (Hz) (V and D are synonymous with the previous) production line. The polyurethane obtained from the disassembly of the refrigerator is made into RDF particles that meet the environmental protection requirements, and then it is incinerated. While realizing the direct recycling and reuse of these materials, the harmful substances are harmless and the experiment in the low temperature and cold environment of (4) 0 ℃ is also without problems, which solves the possible impact on the environment caused by improper disassembly of household appliances

schematic diagram of refrigerator disassembly and recycling of TCL Aobo (Tianjin)

physical recycling method

polyurethane physical recycling method refers to the method of direct utilization after changing the physical form of waste materials without destroying the chemical structure of the polymer itself and changing its basic composition. There are grinding and addition method, bonding processing method, extrusion molding and other methods

crushing and addition method

polyurethane leftovers and old waste materials shall be cut or crushed and screened to obtain fine powder with required particle size before application. Generally speaking, hard polyurethane foam is easy to crush, and its crushing technology is also relatively mature, such as precision cutting technology, flachmatritsen extrusion, etc

the fine pieces or powder of this waste polyurethane after crushing are mostly mixed into raw materials or other materials as fillers for recycling

Anhui Xingang burden Co., Ltd. crushed a large amount of rigid polyurethane recovered from its waste household appliance recycling and dismantling Center and sent it to the company's most advanced polyurethane insulation board production line (imported from Germany) for recycling, which achieved good benefits

according to the literature, if the obtained waste polyurethane powder is added to the raw materials for producing the original parts, and the same parts are produced again, the amount of powder can reach 20% because the powder has the same structure as the raw materials. The mechanical properties of the final products have not been significantly weakened

polyurethane used in waste refrigerators can also be added to polyurethane raw materials as fillers for the production of rim (reaction injection molding) products and the production of energy absorbing foam and sound insulation foam

waste polyurethane materials for refrigerators are often used as fillers for building materials. For example, cement, sand, water and waste rigid polyurethane foam powder are mixed and paved on the bottom layer of the roof surface as the thermal insulation layer of the roof. Its thermal insulation performance is excellent. With strong material base, it promotes the green development and industrial progress of the automotive industry. It has good quality and light weight, and is deeply loved by the construction industry

Japan also has lightweight aggregate products that use waste rigid polyurethane foam as mortar

bonding and pressure molding

rigid polyurethane foam waste materials used in refrigerators are single polyurethane, which is relatively easy to recycle

usually polyphenyl polymethylene polyisocyanate is used as adhesive. The adhesive is evenly dispersed between the waste foam fragments, and the amount of adhesive is about 5% to 10% of the mass of the waste material. After mixing evenly, it is prefabricated into a loose blank pad, placed in a mold coated with release agent, and pressed into a foam particleboard or workpiece under high pressure and heating

due to the excellent water resistance of rigid polyurethane waste particleboard, it is often used to make furniture used on ships. In addition, polyurethane particleboard has good resilience and is widely used as gymnasium floor and polyurethane suspended floor

chemical recovery method

because the polymerization of polyurethane is reversible, polyurethane can be depolymerized under certain reaction conditions to produce monomers

there are six depolymerization methods of polyurethane Rb (2). There are six kinds of chemical recovery technologies: alcoholysis, hydrolysis, alkaline hydrolysis, ammonolysis, pyrolysis and hydrocracking. The monomer products recovered by depolymerization can be directly used in the production of new products

but at present, the industrial technology of chemical recovery method is not mature, and the separation and purification of degradation products is difficult, and it will produce by-products that are difficult to control

Guangzhou jutian Chemical Technology Co., Ltd. has been committed to the subject of waste polyurethane reuse. Taking waste polyurethane as the basic raw material and using the technical scheme of independent intellectual property rights, it has obtained low-cost renewable polyols and other polyurethane products with similar performance to ordinary polyester and polyether polyols, and achieved the closed-loop recycling solution of raw materials products recycling raw materials, which has been successful

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