Critical and strategic metals in mobile phones: A detailed characterisation of multigenerational waste mobile phones and the economic drivers for recovery of metal value

Abstract

Mobile phones have a high embedded value of interest within a circular economy. With the number of these devices operating worldwide expected to reach 18bn by 2025 their low recycling rate leads to large tonnages of End-of-Life Mobile Phones (EoL-MPs) and de facto a challenging waste stream. The rapid replacement of mobile phones to meet consumer demand further compounds the challenges due to increased demand for raw materials, increased energy, and water consumption, and, where uncontrolled and poor disposal at end-of-life occurs, significant impacts on health and the environment.EoL-MPs comprise a complex and heterogeneous combination of materials that include strategically and economically important high technology metals, many of which are classified as critical by the EU. A detailed characterisation of key components (PCBs, casings, screens, cameras, and speakers) of multigenerational (feature phones, multimedia phones, and smartphones) EoL-MPs is studied to determine the potential for recovery of both metal and non-metallic fractions and the economic drivers for recovery of the metal value. On average, the major mass fraction distributed in a mobile phone is: plastics (40%), metals (35%) and ceramics (25%).The results show that 1 tonne of EoL-MPs can contain up to 53 Kg copper, 141 g gold, 270 g silver, 10 g platinum, 18 g palladium and 3.3 Kg rare earth elements, among other valuable metals, with many of these elements found to be at least twice, and in some cases, up to 600 times more concentrated than in their natural ores. The calculated economic value of the EoL-MPs components is in the order: cameras (86,860 US$/ton), printed circuit boards (55,459 US$/ton), speakers (21,853 US$/ton) and screens (3,779 US$/ton). Based on the predicted 5 billion EoL-MPs discarded by the end of 2022, this waste stream has a potential economic value of US$ 9.25 billion. Use of EoL-MPs as a secondary resource-rich stream of these critical materials therefore offers a route to close the materials loop, helps to mitigate the threat to natural resources and the environmental and human health impacts arising from mining operations, relieves supply demands and contributes to the economy.