Leaching of lead from solder material of waste printed circuit boards (PCBs)

Jha, Manis K and Kumari, Archana and Choubey, Pankaj K and Lee , Jae-chun and Kumar, Vinay and Jeong, Jinki (2012) Leaching of lead from solder material of waste printed circuit boards (PCBs). Hydrometallurgy, 121–124 (IF-2.027). pp. 28-34.

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Present work is focused on the selective leaching of lead from the soldering material present on the outer layer i.e. epoxy resin of waste PCBs, liberated through a novel pre-treatment technique of organic swelling using n-methyl-2-pyrrolidone. Nitric acid was found as a suitable leachant to dissolve lead. Initially, the effect of temperature, S:L ratio, leaching time and acid concentration on leaching of lead was investigated using fresh solder material containing 47.36% lead and remaining tin. With 0.2 M HNO3 at S:L ratio 1:100 (g/mL) and temperature 90 °C, 99.99% lead was leached in 120 min. Leaching kinetics followed 1−(1−X)1/3=Kct i.e. chemically controlled reaction model with activation energy 26.94 kJ/mol. Validation of lead leaching from solder of liberated epoxy resin of swelled PCBs indicates that 99.99% of lead could be leached out at 90 °C with 0.2 M HNO3 in 45 min. Tin left in the residue of the liberated resin was further leached with 3.5 M HCl at 90 °C for 120 min at S:L ratio 1:20 (g/mL), which dissolve almost 98.74% tin. Then, metal free epoxy resin was washed with water to utilize it or dispose-of safely without affecting the environment.

Item Type:Article
Official URL/DOI:http://www.sciencedirect.com/science/article/pii/S...
Uncontrolled Keywords:Recycling,Printed circuit boards (PCBs),Solder,Lead,Leaching
Divisions:Metal Extraction and Forming
ID Code:5342
Deposited On:22 May 2012 10:52
Last Modified:23 Apr 2013 12:30
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