Life cycle assessment of emerging technologies on value recovery from hard disk drives

Abstract

Value recovery from end-of-life hard disk drives (HDDs) is a promising strategy to promote a circular economy due to the valuable material content, large availability, and regulated disposal for data security. However, current business practices are limited to reuse or shredding of HDDs for base metal recovery, which are not optimal for environmental sustainability. In particular, the neodymium-iron-boron (NdFeB) magnets, which contain rare earth elements (REEs) that have significant environmental impacts and supply chain risks, are not recovered. To address this challenge, technologies are emerging to enable REE recovery from HDDs. This work focuses on comparing novel technologies, including direct reuse of magnet assemblies, magnet-to-magnet recycling, and recovery of REEs. Life cycle assessment (LCA) was performed on each recovery pathway to quantify and compare the environmental impacts. Primary data were collected from Seagate and other key stakeholders in the HDD value chain. LCA results showed that reusing HDDs is the most environmentally friendly option in terms of global warming potential, reducing CO2 eq. emissions by 5∼18 kg per drive life cycle, when compared to the virgin production and shredding for aluminum recovery. Reuse of magnet assembly is the next best option (reducing ∼1.9 kg of CO2 eq. emissions), followed by magnet-to-magnet recycling (∼1.2 kg of CO2 eq. emissions), and metal recycling (∼0.02 kg of CO2 eq. emissions). Environmental hotspots were also identified, revealing the significant contribution of intercontinental transportation mode for the reverse logistics. Future research is suggested on optimizing the reverse supply chain to reduce the environmental footprint of HDD value recovery.