EP 1051541 A2 20001115 - METHOD FOR ELECTRICALLY REGENERATING CONTAMINATED RHODIUM SOLUTIONS
Title (en)
METHOD FOR ELECTRICALLY REGENERATING CONTAMINATED RHODIUM SOLUTIONS
Title (de)
VERFAHREN ZUR ELEKTROLYTISCHEN REGENERATION VERUNREINIGTER RHODIUMLÖSUNGEN
Title (fr)
PROCEDE DE REGENERATION ELECTROLYTIQUE DE SOLUTIONS DE RHODIUM CONTAMINEES
Publication
Application
Priority
- DE 9900316 W 19990205
- DE 19804534 A 19980205
Abstract (en)
[origin: WO9940238A3] The invention relates to a method for electrically regenerating rhodium solutions, designed especially for regenerating rhodium solutions containing sulphuric acid and/or phosphoric acid or rhodium chloride solutions. The solution to be regenerated is introduced in the anode area (12) of an electrolytic cell (10), which is separated from the associated cathode area (14) by an ion exchange membrane (16), said cathode area being filled with a dilute acid having a good conductivity. The rhodium solution pH is increased so as to reach a value greater than 10, preferably in the range from 10 to 14, by adding an alkaline solution, i.e. a concentrated hydroxide potassium solution. Electrolysis is carried out at electric densities that are so high that the trivalent rhodium of the rhodium solution is oxidised to form an hexavalent rhodium, and possible impurities are depleted by the ion exchange membrane (16) in the catholytes. Hexavalent rhodium is transferred in the cathode area at a speed slightly smaller than trivalent rhodium, and therefore no noticeable rhodium depletion can be observed. This is particularly true when pH during electrolysis is maintained at a value permanently greater than 1.5 by means of proper addition of alkaline solution.
IPC 1-7
IPC 8 full level
C25D 21/18 (2006.01)
CPC (source: EP)
C25D 21/18 (2013.01)
Designated contracting state (EPC)
AT BE CH DE ES FR GB GR IT LI NL
DOCDB simple family (publication)
WO 9940238 A2 19990812; WO 9940238 A3 19990930; AT E209709 T1 20011215; AU 2920599 A 19990823; DE 19804534 C1 19990624; DE 59900461 D1 20020110; EP 1051541 A2 20001115; EP 1051541 B1 20011128; HK 1034544 A1 20011026
DOCDB simple family (application)
DE 9900316 W 19990205; AT 99910109 T 19990205; AU 2920599 A 19990205; DE 19804534 A 19980205; DE 59900461 T 19990205; EP 99910109 A 19990205; HK 01103377 A 20010515