The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 19, 2000
Filed:
May. 07, 1998
Ulrich Reiter, Osnabruck, DE;
Werner Harnischmacher, Osnabruck, DE;
Klaus Fischwasser, Dresden, DE;
Hans-Wilhelm Lieber, Berlin, DE;
Ralph Blittersdorf, Berlin, DE;
Annette Heuss, Teltow, DE;
KM Europa Metal AG, Osnabruck, DE;
Abstract
The invention relates to a method and a device for regenerating exhausted tin-plating solutions which contain tin and copper ions, free complexing agent and complexing agent bound to the copper ions, as well as expended and unexpended reducing agent. By means of a suitable rinsing technique, the rinse water of the tin-plating process is concentrated to a 10 to 15 percent dilution of the process solution. The regenerating solution thus produced is fed to an electrolytic cell. The electrolytic cell comprises a cathode chamber, a middle chamber and an anode chamber. The cathode chamber is separated from the middle chamber by an anion-exchange membrane and the anode chamber is separated from the middle chamber by a cation-exchange membrane. The regenerating solution is initially provided in the cathode chamber. Here, the interfering copper component is cathodically deposited. After an appropriate residence time, the regenerating solution, depleted of copper, is transferred by pumping into the middle chamber where tin enrichment is effected by tin ions diffused from the anode chamber through the cation-exchange membrane. The regenerated solution is subsequently fed back into the tin-plating process.