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 CO2 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 CO2/t metal, respectively. The precise disassembly of e-waste is meaningful for building a future resource sustainable society and for carbon emission reduction.