Leaching and Selective Recovery of Cu from Printed Circuit Boards

Manivannan Sethurajan,Eric D Van Hullebusch

doi:10.3390/met9101034

Abstract

Printed circuit boards (PCBs), a typical end-of-life electronic waste, were collected from an E-waste recycling company located in the Netherlands. Cu and precious metal concentration analyses of the powdered PCBs confirm that the PCBs are multimetallic in nature, rich, but contain high concentrations of Cu, Au, Ag, Pd, and Pt. Ferric sulfate concentration (100 mM), agitation speed (300 rpm), temperature (20 °C), and solid-to-liquid ratio (10 g·L−1) were found to be the optimum conditions for the maximum leaching of Cu from PCBs. The ferric sulfate leachates were further examined for selective recovery of Cu as copper sulfides. The important process variables of sulfide precipitation, such as lixiviant concentration and sulfide dosage were investigated and optimized 100 ppm of ferric sulfate and (copper:sulfide) 1:3 molar ratio, respectively. Over 95% of the dissolved Cu (from the multimetallic leachates) was selectively precipitated as copper sulfide under optimum conditions. The characterization of the copper sulfide precipitates by SEM-EDS analyses showed that the precipitates mainly consist of Cu and S. PCBs can thus be seen as a potential secondary resource for copper.

Highlights

Copper is the second most important nonferrous metal and is being used in many industries ranging from healthcare to construction, machineries to electronics, and telecommunication [1]
The results show that the particle size has a significant effect on the leaching of Cu from Printed circuit boards (PCBs)
This study demonstrated a proof of concept of selective recovery of Cu from PCBs

Summary

Introduction

Copper is the second most important nonferrous metal (after aluminum) and is being used in many industries ranging from healthcare to construction, machineries to electronics, and telecommunication [1]. Chalcopyrite (CuFeS2 ) is the most predominant ore of copper and most often used as the raw material for the extraction of Cu. Other Reduced ores such as chalcocite (Cu2 S). Oxide minerals bearing low-grade ores are used in extractive metallurgies of copper. Copper is produced from the primary sulfidic ores by pyrometallurgy because the hydrometallurgy processes are less successful [3]. In order to overcome this issue, metallurgical industries have started utilizing metal-bearing solid wastes for the recovery of metals [4,5]. A lot of waste materials (metallurgical sludges, residues and slags, etc.) have been used for the extractive metallurgy of Cu [1,6,7,8,9,10]

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Discussion

Conclusion