Abstract

CONTRERAS SILVA, Gilberto  and  ORTEGA DE LA ROSA, José Luis. Electrolytic tin refinement in a Balbach-Thum cell. Rev. Met. UTO [online]. 2016, n.38, pp. 25-31. ISSN 2078-5593.

Industrial scale refining of tin by electrolysis is characterized by a high cost because of the use of phenol sulphonic acid as additive and the generation of a highly pollutant effluent containing phenols. High quality cathodic deposit is not obtained with other additives. In industrial recycling, it is possible to process materials, wastes and scrap for tin refining and valuable metals recovery, as silver, or some other impurities removal, as lead; in these cases, a low cost operation justifies the electro refining industrial practice. This work shows the Balbach-Thum cell as an alternative for electrolysis without phenol sulphonic acid in the electrolyte, but containing other additives as glue and gelatine in some trials and with absence of them in others. Laboratory tests with a lead enriched Lead-free solder, under 0.2 to 0.5 V, electrolysis potential values were taken; more than 90% tin recovery on cathode and full silver and lead removal in anode slimes were obtained, tin quality in accordance with ASTM B 339 standard was produced as well. Current efficiency, energy consumption and current density on equipotential surfaces existing in a laboratory Balbach-Thum cell resulted in reasonable agreement with those for conventional plant cells

Keywords : Electrolytic refinement; tin; Balbach-Thum cell.