Effect of phosphate on lead removal during a copper recycling process from wastes using ammoniacal chloride solution

Effect of additives on monovalent copper electrodeposition in ammoniacal alkaline solutions

“…11. Although we have no definite information to explain this result, our previous study suggested that lead was electrodeposited on copper via a similar mechanism of under-potential deposition (Oishi et al, 2008). Thus, the decrease in the lead content by the addition of gelatin (Fig.…”

“…In concentrated ammonia solutions, however, Pickering et al (1969) reported that up to 0.5 kmol m −3 of Pb(II) could be dissolved under ambient conditions. In fact, the solubility of the Pb(II) compound increased with the ammonia concentration in the present solutions (Oishi et al, 2008), and the copper deposit recovered from the actual printed circuit boards contained a significant amount of lead if the electrolytic solution was not purified in advance . To evaluate the influence of gelatin on the impurity content, a potentiostatic electrolysis was carried out in a solution in which 2.4 mol m −3 PbO was added as the Pb(II) source.…”

“…-3-appliances (secondary resources) using monovalent copper ions (Cu(I)) and ammoniacal alkaline solutions , Oishi et al, 2006, and 2008. In this process, metallic copper in secondary resources such as printed circuit boards is recovered via the following steps: (1) metallic copper is leached as monovalent copper ions (Cu(I)) using divalent copper ions (Cu(II)) as the oxidizing reagent in an ammoniacal alkaline solution, (2) impurities including lead and zinc are removed from the solution by solvent extraction or other techniques, and (3) the purified solution is subjected to an electrowinning step in which metallic copper and Cu(II) are formed on the cathode and anode, respectively, from Cu(I).…”

Ammoniacal leaching and recovery of copper from alloyed low-grade e-waste

“…Lim et al [10] reported leaching of lead powder in ammonium-ammonium sulfate bath and after initial lead dissolution a decrease of Pb(II) ions concentration was observed in relatively short time period. Oishi et al [16] stated that metallic lead can be easily oxidized by copper(II) ions to Pb(II) species in ammoniacal solutions. Authors found that increased ammonia concentration in ammonium chloride solutions was accompanied by enhanced lead solubility.…”

The ammonia leaching of alloy produced from waste printed circuit boards smelting process

“…In the ammonia leaching for copper, cupric (Cu 2þ ) amine could be used as oxidant, and the complex ions are able to be reused by electrical oxidation Koyama, Tanaka, Miyasaka, & Lee, 2006;Oishi, Koyama, Konishi, Tanaka, & Lee, 2007;Oishi, Yaguchi, Koyama, Tanaka, & Lee, 2008a, 2008b. Ammonia leaching processes have been developed and investigated to recover valuable metals such as copper, gold, silver, cobalt, and nickel (Yoo & Kim, 2012).…”