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. 14, 1999
Filed:
Apr. 10, 1997
Agfa Gevaert, Mortsel, BE;
Abstract
An apparatus for de-silvering silver-containing solutions comprises an electrolytic cell (10) having an anode (20), a cathode (30) and a reference electrode (45) positioned adjacent the cathode (30), and electrical power supply control means (41) for controlling the supply of electrical power to the anode (20) and the cathode (30). Operation of the cell (10) is controlled potentiostatically while the current exceeds a certain threshold value and the current is controlled galvanostatically at that threshold (minimum) value in circumstances in which the potentiostatic control would result in a current below the threshold value. To this end, the power supply control means (41) includes means (60) for adjusting the cathode potential and control means (70) linked to said adjustment means (60) for controlling operation of the cell potentiostatically at a selected cathode potential, means for monitoring the current drawn through the cell during such potentiostatic control and for comparing such current with a threshold current, and means for controlling the cell galvanostatically at such threshold current value, means for switching from potentiostatic to galvanostatic control in response to cell current dropping below said threshold value, means for periodically re-establishing said selected cathode potential, and means for reverting from galvanostatic to said potentiostatic control in response to a cell current above said threshold value when said selected cathode potential is re-established.