Leaching copper from shredded particles of waste printed circuit boards

Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids

“…3 that copper leaching rate increases with the increase of hydrogen peroxide adding amount until it reaches to or over 5 mL. According to previous studies, oxygen, from the decomposition of hydrogen peroxide, reacts with metal copper to form cupric oxide, which further reacts with IL acid to form cupric sulfate (Yang et al, 2011;Zhu et al, 2011). Then, IL acid and hydrogen peroxide together act as the reactants.…”

“…As shown in Fig. 2, almost all the copper leaching rates increase with the increase of IL acid (Hoang et al, 2011;Yang et al, 2011;Zhu et al, 2011). Reasons for this should be further studied.…”

“…3, further increasing hydrogen peroxide, copper leaching rate decreases, especially for [BSO 3 HMIm]HSO 4 , which decrease from 65.01% to around 1% when hydrogen peroxide adding amount increases from 5 mL to 10 or 15 mL. This is quite different from other inorganic acid leaching system (Yang et al, 2011(Yang et al, , 2014. Overdosed hydrogen peroxide may cause the oxidation of IL acid since it decomposes to release fresh oxygen.…”

“…Among these processes, hydrometallurgic processes offer high metal selectivity and recovery with a flexible mode of operation and suitability for small scale applications, making it an attractive alternative for the treatment of WPCBs. In previous studies, different lixiviant systems, including sulfuric acid, hydrochloric acid, nitric acid, iodide, ammonia, cyanide, thiourea, thiosulphate and microbes, were examined (Huang et al, 2014;Li et al, 2012;Oishi et al, 2007;Hu et al, 2006;Yang et al, 2011). In most cases, an oxidant, usually hydrogen peroxide (H 2 O 2 ) and ferric (Fe 3+ ) due to their high reduction potentials of 1.78 V and 0.77 V, was involved given that metals in WPCBs are found in native and/or alloy form (Birloaga et al, 2013).…”

Synthesis of cuprous chloride and simultaneous recovery of Ag and Pd from waste printed circuit boards

“…Hence, recovery of those metals is the inherent motivity in waste PCBs disposal. Many recycling techniques of copper from waste PCBs have been developed such as pyrometallurgy [13], hydrometallurgy [14][15][16], mechanical methods [17,18]. In the past two decades, the most active research area on recovery of metals from electronic scraps is recovering metals by hydrometallurgical techniques [11].…”