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Continuous Process for Recovering K3fe(cn)6

IP.com Disclosure Number: IPCOM000101136D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 31K

Publishing Venue

IBM

Related People

Foery, M: AUTHOR [+3]

Abstract

Potassium-hexacyanoferrate-III (K3Fe(CN)6) used as an etchant for metals is recovered continuously by the anodic oxidation of potassium-hexacyonaferrate-II (K4Fe(CN)6) formed during etching.

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Continuous Process for Recovering K3fe(cn)6

       Potassium-hexacyanoferrate-III (K3Fe(CN)6) used as an
etchant for metals is recovered continuously by the anodic oxidation
of potassium-hexacyonaferrate-II (K4Fe(CN)6) formed during etching.

      The figure is a schematic of the apparatus used for the
process.  The etching bath, contained in tank 1, is continuously
cycled via line 2 into the bottom part of section 5 in tank 4 by
pump 3.  In tank 4, the recovery takes place.  Section 5 is the anode
compartment in which anode 6 immerses.  Section 7 in tank 4, which is
the cathode compartment, is separated from section 5 by a
semipermeable membrane 9 preferably of Nafion*.  Cathode 8 immerses
in section 7.  The etching bath with the recovered K3Fe(CN)6 is
recycled from section 5 into tank 1 via line 10.  The catholyte in
section 7 consists of a potassium hydroxide solution and cathode 8 of
titanium.  Anode 6 is made of titanium which is coated with
iridium-tantalum oxide.  The anodic oxidation is effected
potentiostatically at about 2.5 V.  No oxidation byproducts are
formed.
*  Trademark of E. I. du Pont de Nemours & Co.