Track: Waste Management
Abstract
This study evaluated the potential to extract gold from e-waste mainly focusing on printed circuit boards (PCBs). E-waste was first separated physically and then went through dissolution. Cyanide leaching and Aqua Regia leaching using various precipitating reagents such as zinc (Zn), aluminum (Al), Na2S2O5, FeSO4, NaBH4 on Zn and NaBH4 on Al. The process was conducted at pH of 11.8 and 12.4. Gold extracted through cyanidation leaching with NaBH4 on Zn precipitation resulted in gold extraction of 99.0% in comparison to leaching with Aqua Regia with NaBH4 on Zn precipitation to yield gold content of 91.9%. The e-waste processing plant was assumed to process 20000 tons per annum of PCBs with a gold yield of 1.4 tons and total power requirement of almost 203 000 KWhr. A total capital investment of USD 15 million was required with a payback period of 1.04 years and a return on investment of 0.96. E-waste can be utilized as a raw material to recover precious metals.