Monitoring the Resources and Environmental Impacts from the Precise Disassembly of E-Waste in China

Abstract

Due to the dispersed distribution of e-waste and crude disassembly in traditional recycling, valuable metals are not traceable during their life cycle. Meanwhile, incomplete separation between metals and nonmetals reduces the economic value of disassembled parts, which leads to higher environmental costs for metal refining. Therefore, this study proposes a precise disassembly of e-waste to finely classify and recover metals in an environmentally friendly way. First, the macroscopic material flow of e-waste in China (source, flow, scrap, and recycling gap) was measured based on data collected by the government and 109 formal recycling enterprises. The sustainable recycling balance time points for e-waste recycling and scrap volumes were forecast by introducing an additional recycling efficiency. By 2030, the total scrap volume of e-waste is predicted to reach 133.06 million units. For precise disassembly, the main metals and their percentages from these typical e-wastes were measured based on material flow analysis combined with experimental methods. After precise disassembly, the proportion of reusable metals increases significantly. The CO 2 emission of precise disassembly with the smelting process was the lowest compared with crude disassembly with smelting and ore metallurgy. The greenhouse gas for secondary metals Fe, Cu, and Al was 830.32, 1151.62, and 716.6 kg CO 2 /t metal, respectively. The precise disassembly of e-waste is meaningful for building a future resource sustainable society and for carbon emission reduction.

Dynamic Environmental–Economic Impacts Analysis of Upgrading e-Waste Recycling from Crude Disassembly to Precise Disassembly

“…The metal parts disassembled but not meeting the reuse standards will flow into downstream metal recycling enterprises and undergo a refinement process. Due to the lack of primary data on the metal refinement process, we collected relevant information from the literature sources, , and the treatment capacity of refinement plant is 600 kg/h raw materials. We considered Fe, Cu, Al, mixed-metal parts refinement, and the wastewater treatment process simultaneously.…”

“…19 This method entails accurately locating and removing specific tiny components through a more-thorough disassembly process, thereby enhancing the separation of different electronic components. 20,21 In theory, PD is anticipated to reduce the environmental burden and elevate the economic value of products, which is achieved by simplifying the subsequent refining process and increasing the metal purity of disassembled parts.…”

“…First, while PD has the potential to reduce the environmental burdens of metal refinement and increase the economic value of dismantled parts, its environmental-economic superiority remains ambiguous due to higher energy input and labor costs involved in the dismantling process. 21,22 Second, the suitability of PD for e-waste may be influenced by the diverse material compositions in different e-waste types. Certain categories of e-waste could present challenges to the practical application of PD, due to the low value of tiny components.…”

“…This incomplete separation results in increased pollutants discharge and higher costs during subsequent metal refinement process. , In response to these challenges, precise disassembly (PD) has garnered significant attention in recent years . This method entails accurately locating and removing specific tiny components through a more-thorough disassembly process, thereby enhancing the separation of different electronic components. , In theory, PD is anticipated to reduce the environmental burden and elevate the economic value of products, which is achieved by simplifying the subsequent refining process and increasing the metal purity of disassembled parts.…”

“…However, several issues need to be addressed. First, while PD has the potential to reduce the environmental burdens of metal refinement and increase the economic value of dismantled parts, its environmental-economic superiority remains ambiguous due to higher energy input and labor costs involved in the dismantling process. , Second, the suitability of PD for e-waste may be influenced by the diverse material compositions in different e-waste types. Certain categories of e-waste could present challenges to the practical application of PD, due to the low value of tiny components. , Finally, the carbon emission and economic benefits of e-waste recycling may undergo changes under different time boundaries, influenced by social development and energy structure upgrades, which make new requests for environmental and economic calculation. − Therefore, it is essential to compare the dynamic environmental and economic impacts of CD and PD, thereby promoting sustainable development of the e-waste recycling industry.…”