Waste Printed Circuit Boards (WPCBs) of Mobile Phones in Hydrometallurgical Route: A Systematic Review

Abstract

Due to the lockdown and restrictions imposed to confront COVID-19 pandemic over the past, mobile phone sales spiked to reach 7.1 billion in 2021 which predicts in a massive increase of waste from mobile phones and subsequently an increase of waste printed circuit boards (WPCBs) associated with mobile phones. WPCBs contain a variety of precious and base metals such as copper, gold, nickel, zinc and many more. The recycling of these WPCBs for the recovery of those metals is extremely attractive from economic and environmental perspectives. Published studies shows that hydrometallurgical process is economical and less hazardous to the environment in recycling WPCBs compared to other techniques. This review summarises and analyses the research results of hydrometallurgical process for the recycling of WPCBs from mobile phones in recent years with focusing on two phases of the hydrometallurgical route, leaching and purification. We conducted a systematic search in three electronic databases of original full-length articles, namely Web of Science, Science Direct, and Scopus, for studies related to recycling WPCBs from mobile phones by using a hydrometallurgical process between 2015 and 2021. In total, we found 129 records. For eligibility, 121 full-text publications were reviewed; 120 were excluded, resulting in the inclusion of 9 published studies that matched the predetermined eligibility criteria. This review concludes with recommendations for future research on the selection of optimal leaching and purification techniques for metal recovery from WPCBs particularly of mobile phones.