Examining the feasibility of the urban mining of hard disk drives

Cities are becoming one of the greatest generators of waste and thus a potential source of secondary materials. One of the most attractive waste streams in cities is waste electrical and electronic equipment (WEEE) as they contain many valuable metals, mainly in the printed circuit board (PCB), with a high risk of a disruption in their supply. Many of the PCBs contained in small WEEE are separated by destructive operations, as the economic feasibility of their separation using non-destructive operations remains unclear. This paper examines the feasibility of separating the PCB and the permanent magnets (PMs) contained in hard disk drives (HDD) using non-destructive operations. The economic cost of separating these parts is evaluated by the disassembly sequences, the disassembly schemes, and using the ‘ease of Disassembly Metric’ (eDiM). In HDD, the economic cost for the non-destructive separation of the PCB is €0.05 while the cost to harvest the PCB as well as the PMs is €0.39. In both cases, such cost is well below the estimated economic value of the gold, silver, and palladium contained in the PCB (€0.85). As a result, the paper concludes that the separation of the PCB and the PMs of HDDs is economically profitable. Measures for promoting the non-destructive separation of the PCBs and the PM of HDDs should be further promoted, as they could help improve the supply of secondary raw materials.