2014-Sustainable Industrial Processing Summit
SIPS 2014 Volume 4: Recycling & Secondary Battery
| Editors: | Kongoli F |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2014 |
| Pages: | 498 pages |
| ISBN: | 978-1-987820-06-5 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
CD shopping page
Complex evaluation of the processes and efficiency of electrolytic tin scrap refining in HCl-SnCl2 solutions
Tamas Kekesi1; Tibor Kulcsar1;1UNIVERSITY OF MISKOLC, Miskolc, Hungary;
Type of Paper: Regular
Id Paper: 39
Topic: 5
Abstract:
The waste material generated by the soldering technology massively applied in the electronic industry represents not only an environmental issue, but also a secondary resource of the contained valuable metals. With the dominance of the lead-free soldering alloys, the recycling of the high value tin - and occasionally silver - has been shown possible by electrolysis in chloride solutions. The difficulties of the procedure caused by the irregular electro-crystallization, cathode corrosion and impurity carry over have been targeted by examining the electrode processes characteristic of different anode and electrolyte compositions. Potentiodynamic examinations at different levels of tin concentration and stirring of the solution have pointed out the strong influence of material transport on the cathodic process. This effect was also studied in the refining cell by applying conductivity sensors and iodometric analysis of the Sn(II)/Sn(IV) distribution. The stratification of the tin concentration by height and unfavorable generation of Sn(IV) species at the anode were observed. These phenomena cause disturbances in the electro-crystallization and the stability of the solution. The overall process taking place in the cell was examined by in situ detection and recording of the mass changes. The expression of materials balances justified the assumed processes leading to cathode corrosion and irregular deposition. The product could be achieved with higher purity than technical standards.