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

Abstract

h i g h l i g h t s• An environmentally friendly process was developed for high quality cuprous chloride synthesis from waste PCBs.• Neither corrosive acid nor strong oxidant was used in the process.• Ag and Pd were simultaneously recovered during cuprous chloride synthesis.• A much faster reaction rate was achieved compared with other recovery methods.a r t i c l e i n f o t r a c tA benign and effective process for cuprous chloride synthesis and simultaneously recovery of Ag and Pd from waste printed circuit boards (PCBs) was developed in the present study. The main merit of the process is that neither corrosive acid nor strong oxidant was used. The PCBs were firstly pretreated by thermal shock process to obtain metallic particles (MPs), then cuprous chloride was synthesized by reacting MPs with cupric sulfate in the presence of sodium chloride. The optimum V Nacl /m CuSO 4 (mL/g) ratio, [Cu]/[Cu 2+ ] mole ratio, treatment time and operation temperature were 6, 0.95, 30 min and 60 • C, respectively. Approximately 98.5% of Cu could be recovered from the PCBs through two synthesis circles. During the synthesis process, Ag and Pd could be simultaneously recovered by forming a stable chloride complex since Cu 2+ played the role of oxidant in the system. The recovery percentages of Ag and Pd were 93.9% and 95.3%, respectively. Accordingly, it is believed that the process developed in the current study is benign and practical for copper and precious metal (Ag, Pd) recovery from waste PCBs.

Selective recovery of palladium from waste printed circuit boards by a novel non-acid process

“…were disassembled when we received these materials. The PCBs were pretreated by thermal shock process [27] and crushed in a hammer crusher. Then, a centrifugal air separator was used to obtain the metallic components.…”

“…Palladium was enriched during copper recovery process according to our previous study [27,28] with minor modification. The flow chart of the whole process was shown in Fig.…”

Direct extraction of palladium and silver from waste printed circuit boards powder by supercritical fluids oxidation-extraction process

“…and then their product precipitated in the PMC. Oxidation and complexation reactions between Cu 2+ and Pd/Ag were shown as follows [29]:…”

“…Very few researches have been carried out on the enrichment characteristics of precious metals under supercritical conditions. Our previous studies revealed that dispersal precious metals in electronic waste could be enriched by a non-acid process and extracted by solvent methods [28,29]. However, the treatment of waste liquors after the solvent extraction process is inevitable.…”

Assessment of heavy metals exposure, noise and thermal safety in the ambiance of a vacuum metallurgy separation system for recycling heavy metals from crushed e-wastes

“…Many scholars have done a lot of research and mainly focus on the extraction of valuable metals like Au, Ag and Cu from various kinds of e-wastes (Hagelüken, 2006;Park and Fray, 2009;Zhang and Zhang, 2013). Although the heavy metal contamination has been reported a lot, the recycling of heavy metals like Pb, Cd and Zn in e-wastes has not attracted enough attention because of their nominal prices.…”