Leaching of lead from solder material used in electrical and electronic equipment

Abstract

Present work is a part of developing novel recycling tec-hnique for waste printed circuit boards (PCBs) i.e. the liberation of metals from PCBs by organic swelling follow-ed by the treatment of resin to remove/ recover hazardous soldering materials. In order to recover the hazardous metallic constituent lead from the liberated resin, init-ially the leaching studies were made using fresh solder co-ntaining 63.9% Pb and remaining tin. Experimental results obtained in different conditions viz. time,temperature and acidity showed ~97.20% of lead dissolution with 6M HNO3 at solid to liquid (S:L) ratio 1:10 (g/mL) and temperature 90oC in 75 minutes. The result of the studies validated with crushed PCBs shows that almost total lead and tin was leached out with 6M HNO3 and 6M HCl respectively at S:L ratio 1:10 (g/mL) and temperature 90oC within 50 minutes. The results will be useful for the treatment and safe dis-posal of PCBs resin.