| Title |
Recovery of Tin and Nitric Acid from Spent Solder Stripping Solutions |
| Authors |
(Jae-woo Ahn); (Seong-hyung Ryu); (Tae-young Kim) |
| DOI |
https://doi.org/10.3365/KJMM.2015.53.6.426 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
tin; nitric acid; diffusion dialysis; recovery; solder stripping solution |
| Abstract |
Spent solder-stripping solutions containing tin, copper, iron, and lead in nitric acid solution, are by-products of the manufacture of printed-circuit boards. The recovery of these metals and the nitric acid, for re-use has economic and environmental benefits. In the spent solder-stripping solution, a systematic method to determine a suitable process for recovery of valuable metals and nitric acid was developed. Initially, more than 90% of the tin was successfully recovered as high-purity SnO2 by thermal precipitation at 80 ℃ for 3 hours. About 94% of the nitric acid was regenerated effectively from the spent solutions by diffusion dialysis, after which there remained copper, iron, and lead in solution. Leakage of tin through the anion-exchange membrane was the lowest (0.026%), whereas Pb-leakage was highest (4.26%). The concentration of the regenerated nitric acid was about 5.1 N. |