Recycling

Biography

Biography: Arda IÅžILDAR

Abstract

Discarded electric and electronic devices comprise a growing segment of waste generated at households. Despite the growing awareness and deterring legislation, most of the waste electrical and electronic equipment (WEEE) is disposed improperly. Global WEEE generation reached 41.8 million tons in 2014, and forecasted to rise to 50 million tons in 2018 (Baldé et al., 2015). In addition to the prevalence of toxic compounds, WEEE also contains valuable metals such as copper, gold, aluminum and nickel. Particularly printed circuit boards (PCB) have the potential to be a very promising secondary source of metals. Recovery of metals is conventionally carried out by pyrometallurgical and hydrometallurgical methods, which have their own drawbacks and limitations. In this research, sustainable metals recovery technologies, with an emphasize on biological methods, were investigated. In this direction we test the effectivity of bioleaching, chemical leaching and subsequent recovery of metals from discarded PCB. In addition, sustainability assesment was evaluated using LCA and LCC methodology. Results showed high concentrations of the metals of interest the discarded circuit boards from various devices. Copper was bioleached from discarded circuit boards with a high (>98%) efficiency with mixture of acidophilic bacteria in batch reactors. Gold was bioleached from discarded circuit boards at a (>44%) efficiency with cyanide generating bacteria. Copper was selectively recovered in a subsequent electrowinning process separated from other metals. Sustainability assessment of the technology showed that the process has lower impact on the environment compared to BAT.