Recovery of metal from solution
AssigneeEastman Kodak Company
InventorsNicholas J. Dartnell, Christopher B. Rider
Life of this patent
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Abstract
The invention relates to a method for controlling the recovery of a metal, such as silver, from a solution flowing through an electrolytic cell. A constant current is applied between the anode and cathode of the cell and the rate of change of the voltage monitored, the information obtained from the monitored change of voltage being used to control the rate of recovery of the metal.
Claims28
A method of controlling the recovery of metal from solution flowing through an electrolytic cell containing a cathode and an anode by deposition onto the cathode thereof as current flows through the cell between the cathode and the anode under the action of a voltage thereacross, comprising the steps of
- a) applying one of a first constant current or voltage at a first average solution flow rate,
- b) changing the solution flow rate to a second average flow rate for a first period of time,
- c) monitoring the other of the current or voltage during the period of time, and
- d) obtaining information from the monitored current or voltage, the information being used to control the rate of recovery of metal from the solution.
A method of controlling the recovery of metal from solution flowing through an electrolytic cell containing a cathode and an anode by deposition onto the cathode thereof as current flows through the cell between the cathode and the anode under the action of a voltage thereacross, comprising the steps of
- applying one of a first constant current or voltage at a first average solution flow rate,
- changing the solution flow rate to a second average flow rate for a first period of time,
- monitoring and storing the other of the current or voltage during the first time period,
- restoring the solution flow rate to the first flow rate,
- changing the one of the current or voltage to a second constant current or voltage,
- changing the solution flow rate to the second average flow rate for a second period of time,
- monitoring and storing the other of the current or voltage during the second period of time,
- obtaining information from the stored currents or voltages, and selecting and applying a current or voltage from the first and second current or voltage levels in response to the information obtained
- thereby to control the rate of recovery of metal from the solution.
A method of controlling the recovery of metal from solution flowing through an electrolytic cell containing a cathode and an anode by deposition onto the cathode thereof as current flows through the cell between the cathode and the anode under the action of a voltage thereacross, comprising the steps of
- reducing the flow rate of the solution for a period of time,
- monitoring the rate of change in one of the current flowing and voltage difference between the cathode and the anode due to variation in the concentration of the metal in the solution during this period of time and modifying the other of said current and voltage in response to said monitored rate of change or voltage difference thereby to control the rate of recovery of the metal from the solution.
A method of controlling the recovery of metal from solution flowing through an electrolytic cell containing a cathode and an anode by deposition onto the cathode thereof as current flows through the cell between the cathode and the anode under the action of a voltage thereacross, in which information obtained from monitoring the current or the voltage which is subsequently used for controlling the rate of recovery is obtained during periods of reduced average solution flow.
Apparatus for controlling the recovery of metal from solution flowing through an electrolytic cell containing a cathode and an anode by deposition onto the cathode thereof as current flows through the cell between the cathode and the anode under the action of a voltage thereacross, comprising
- a) means for applying one of a first constant current or voltage at a first average solution flow rate,
- b) means for changing the solution flow rate to a second average flow rate for a first period of time,
- c) means for monitoring the other of the current or voltage during the period of time, and
- d) means for obtaining information from the monitored current or voltage,
- the information being used to control the rate of recovery of metal from the solution.
Apparatus for controlling the recovery of metal from solution flowing through an electrolytic cell containing a cathode and an anode by deposition onto the cathode thereof as current flows through the cell between the cathode and the anode under the action of a voltage thereacross, comprising
- means for applying one of a first constant current or voltage at a first average solution flow rate,
- means for changing the solution flow rate to a second average flow rate for a first period of time, means for monitoring and storing the other of the current or voltage during the first time period,
- means for restoring the solution flow rate to the first flow rate, means for changing the one of the current or voltage to a second constant current or voltage,
- means for changing the solution flow rate to the second average flow rate for a second period of time,
- means for monitoring and storing the other of the current or voltage during the second period of time,
- means for obtaining information from the stored currents or voltages, and
- means for selecting and applying a current or voltage from the first and second current or voltage levels in response to the information obtained
- thereby to control the rate of recovery of metal from the solution.
Apparatus for controlling the recovery of metal from solution flowing through an electrolytic cell containing a cathode and an anode by deposition onto the cathode thereof as current flows through the cell between the cathode and the anode under the action of a voltage thereacross, comprising
- means for reducing the flow rate of the solution for a period of time,
- means for monitoring the rate of change in one of the current flowing and voltage difference between the cathode and the anode due to variation in the concentration of the metal in the solution during this period of time and
- means for modifying the other of said current and voltage in response to said monitored rate of change or voltage change
- thereby to control the rate of recovery of the metal from the solution.
Dependencies are inferred from the claim text.