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Types of Recycling

When the automobiles, home appliances, beverage containers, buildings, and other products that support our daily lives reach the end of their useful lives, the materials that make up these products have various fates. Some of the materials are disposed of directly in landfills, but many are recycled in various ways. There are two main types of material recycling: open loop recycling and closed loop recycling, and open loop recycling can be further divided into heat recovery and cascade recycling.

While open-loop recycling (heat recovery and cascade recycling) is a linear recycling, closed-loop recycling establishes a true closed-loop, and is superior to open-loop recycling in terms of sustainability, as it reduces the consumption of new natural resources, reduces the emission of environmentally hazardous substances, and reduces waste.

Figure 1: Types of Recycling

Figure 1: Types of Recycling

Source: NIPPON STEEL CORPORATION

 

  • Energy recovery (Open-loop recycling)

    This is a recycling process in which waste is incinerated to reduce its volume, and the heat generated is recovered and used to produce electricity and hot water. It is an alternative to fuel, but requires the disposal of combustion ash and other waste. Since the material going through this process does not return to the original material, it is a type of open-loop recycling, which is recycling without a closed loop.

    In Japan, this is the main method used to dispose of combustible materials.

  • Cascade recycling (Open-loop recycling)

    It is an open-loop recycling where the material is reused as a material, but its properties are degraded and changed, so it never returns to the original material. There are two types of cascade recycling: material recycling, in which the properties of the material are reused as they are, and chemical recycling, in which the material is decomposed and used as a raw material for other purposes. Both types of cascade recycling are limited to finite cycles and are ultimately reaches the point of final disposal in the form of landfill.

    Some aluminum, plastics, and chemical fibers are recycled in this way.

  • Closed-loop recycling

    It is a type of recycling that reuses the material as a material. In closed-loop recycling, the material resets to the same material through removal of impurities.

    Steel is a typical closed-loop recyclable material. Especially because it can be easily collected and sorted due to its magnetic property, a high closed-loop recycling rate is achieved (*1).

    (*1) For example, the apparent recycling rate of automotive steel in Japan ranges from 97% to 89% (Figure 2), and the recycling rate of steel cans is as high as 89% to 93.3% (Figure 3).

     

Figure 2: Apparent recycling rate of automotive steel in Japan

Data Source: JAMA, Trade Statistics of Japan (Ministry of Finance), Japan Automobile Recycling Promotion Center

 

・In the case of steel materials, the recycling rate can be estimated based on the number of units, because it is almost completely recovered by the ELV (end of life vehicle) recycling process. 
・The actual recycling rate is estimated to be even higher, because a large percentage of the deviation (f-g) is estimated to be used as automobile parts domestically or abroad.

Figure 3: The recycling rate of steel cans

Data source:Japan Steel Can Recycling Association

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