Recovery of metal from solution
AssigneeEastman Kodak Company
InventorsNicholas J. Dartnell, Christopher B. Rider, Bruce S. Gowans
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Abstract
Recovery of silver from a photographic fixer solution in an electrolytic cell is controlled so as to maintain a high current efficiency whilst minimizing unwanted side effects. The rate of change of plating voltage at constant current through the cell is monitored, and in response to detection of a maximum value thereof the current is reduced to a new constant level. Such control allows the cell to be operated continually at high current efficiency in response to changing chemical conditions within the cell.
Claims20
A method of controlling the recovery of metal from solution flowing through an electrolytic cell by deposition onto a cathode thereof, comprising the steps of monitoring the rate of change in one of the (a) current flowing and (b) voltage difference between the cathode and an anode of the cell, due to variation in the concentration of the metal in the solution, and modifying the other of said current and voltage in response to said monitored rate of change thereby to control recovery of the metal from the solution.
Apparatus for controlling recovery of metal from solution, wherein the solution is contained in an electrolytic cell having an anode and a cathode, comprising means for monitoring the rate of change in one of (a) the current flowing and (b) voltage difference between the cathode and the anode of the cell due to variation in the concentration of the metal in the solution, means for modifying the other of said current and voltage in response to said monitored rate of change, and means for controlling operation of the monitoring means and the modifying means.
Dependencies are inferred from the claim text.