“…In recent years, many researchers have investigated a number of approaches on copper recovery from WPCBs, including pyrometallurgical process (Cui and Zhang, 2008;Duan et al, 2012;Li et al, 2010), hydrometallurgical process (Kim et al, 2011a,b;Park and Fray, 2009;Syed, 2012;Tuncuk et al, 2012;Yang et al, 2012;Zhu et al, 2009), bioleaching process (Zhu et al, 2011), supercritical water oxidation process (Xiu and Zhang, 2010) and mechanical process (Havlik et al, 2014;Zhang and Forssberg, 1997). In China, mechanical process is the first choice and has been widely and successfully applied in industry, because it can recycle copper without consuming a great amount of energy when compared to pyrometallurgical process, and it also would not consume leaching agents and produce secondary waste water when compared to hydrometallurgical process (Havlik et al, 2014).…”