2010 Volume 51 Issue 7 Pages 1350-1353
In recent years, the major issue posed by the recycling of tin-lead and lead-free solder residues is to recycle effectively lead-free solder residues because large volume of lead-free solder residues has been generated from electric and electronic industry as the environmental regulation becomes to be strictly in Europe. In general, the lead-free solder residues are generated from the step to affix components to printed circuit boards, which contains 2–4% of silver and 90–93% of tin. In this study, a novel cyclic process to separate silver from the lead-free solder residues using a metal solvent has been developed. The process uses zinc as a metal solvent which selectively forms intermetallic compounds with silver, followed by the volatilization separation step to recover zinc which can be reused as the metal solvent. Based on the results obtained, up to 90% of the silver in a lead-free solder residue was calculated to be separated into the dross phase through the sixth silver separation stage using the proposed process. This paper is only concerned with the results for the separation of silver from a lead-free solder residue using zinc as a metal solvent.