WO2014076169A1 - Appareil industriel adaptatif et procédé permettant le dépôt électrolytique du cuivre - Google Patents

Appareil industriel adaptatif et procédé permettant le dépôt électrolytique du cuivre Download PDF

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Publication number
WO2014076169A1
WO2014076169A1 PCT/EP2013/073800 EP2013073800W WO2014076169A1 WO 2014076169 A1 WO2014076169 A1 WO 2014076169A1 EP 2013073800 W EP2013073800 W EP 2013073800W WO 2014076169 A1 WO2014076169 A1 WO 2014076169A1
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Prior art keywords
potential difference
power supply
tanks
electrical
tank
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PCT/EP2013/073800
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English (en)
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Przemyslaw Zaprzalski
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Przemyslaw Zaprzalski
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Publication of WO2014076169A1 publication Critical patent/WO2014076169A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
    • C25C1/12—Electrolytic production, recovery or refining of metals by electrolysis of solutions of copper
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C25C7/06—Operating or servicing

Definitions

  • the invention pertains to an adaptive industrial apparatus and adaptive industrial process for the electrolytic deposition of copper in which the power supply for the deposition process is controlled in accordance with monitored electrical potential differences between the electrodes.
  • the process is applicable to the electrorefining of copper and also the electrowinning of copper.
  • the high quality deposition of copper during electrorefining or electrowinning is understood to require the lowest possible level of deposited impurities whilst maximising the deposition rate.
  • Such high quality deposition is observed when deposition occurs with an electrical potential difference between the cathode and anode being within the so called plateau region, or at smaller potentials. In the case of the smaller potentials the deposition rate is lower with respect to the plateau region potentials and is a non-linear function of the potential difference.
  • FIG 5a illustrates a typical known industrial copper electrorefining arrangement.
  • a few hundred “tanks”, each containing a few tens of anodes and cathodes immersed in electrolyte, are connected in series to a power supply, PS.
  • the tanks are organized into groups illustrated as G1 ... GN-1 , GN in Figure 5a, the groups being arranged in series.
  • Figure 5b illustrates a single selected group (such as GN-1 ).
  • the group GN-1 is formed from a number, M, of tanks, for example 8 or 12, these being labelled T1 ...TM in Figure 5b. Each tank is connected in series with its neighbouring tanks as can be seen from Figure 5b.
  • the tanks can be electrically isolated or removed from the series circuit by the operation of a switch S which provides a short-circuit across the group GN-1 of tanks thereby providing a low impedance between the power connections for tanks T1 and TM. This enables the provision of maintenance or service works while the remaining tanks in the circuit continue with their production of copper.
  • the power supply operates at currents in the range 10.5kA to 1 1 .5kA.
  • the operational voltage measurable across the tanks is in the range 0.25V to 0.35V and the current density used is in the range 220Am "2 to 235 Am "2 .
  • each tank contains 34 cathodes and 35 anodes.
  • the power supply operates at currents in the range 15.5kA to 19kA.
  • the operational voltage measurable on the tanks is in the range 0.20V to 0.45V and the current density used is in the range 180 Am “2 to 220 Am "2 .
  • the copper electrodeposition industry looks for methods to enhance the productivity and the space-time-yield while keeping copper deposit purity standards at the maximum level (for example sufficient to meet the Copper grade A (Cu-CATH-01 ) standard according to the London Metals Exchange).
  • the industry uses the highest possible current density in favourable physical and chemical conditions including precisely controlled anode quality, inhibitors, electrolyte flow, temperature, electrolyte composition, structure of starting blank, quality of electrical contacts, precision of anode-cathode positioning, and so on.
  • the copper electrorefining industry is presently managing electrorefining processes by control of current density using industrial power supplies. It is in this context that the present invention has been realised.
  • an industrial apparatus for the electrolytic deposition of copper comprising:
  • each tank being configured to retain an electrolyte and having at least one anode and at least one cathode positioned within the electrolyte when in use;
  • a direct current power supply for providing electrical power to the plurality of tanks so as to cause the electrolytic deposition of copper in each tank, wherein the deposition tanks are connected in use in an electrical series circuit with the direct current power supply;
  • a potential difference monitoring system configured to monitor the respective electrical potential differences between pairs of locations within the electrical series circuit, each pair of locations comprising the at least one anode and at least one cathode in a respective deposition tank;
  • a controller configured to modulate the electrical output of the direct current power supply in dependence upon the potential difference monitoring system.
  • an industrial process for the electrolytic deposition of copper using an industrial apparatus which comprises a plurality of deposition tanks, each tank being configured to retain an electrolyte and having at least one anode and at least one cathode positioned within the electrolyte; and a direct current power supply which provides electrical power to the plurality of tanks so as to cause the electrolytic deposition of copper in each tank, wherein the deposition tanks are connected in use in an electrical series circuit with the direct current power supply; the process comprising:
  • each pair of locations comprising the at least one anode and at least one cathode in a respective deposition tank;
  • the first and second aspects of the invention therefore provide, respectively, a novel apparatus and process for the electrolytic deposition of copper.
  • Each aspect uses the monitoring of electrical potential differences across the electrodes in the tanks to control the electrical output of the power supply. Hence it is the information regarding the numerous electrical potential differences across the tanks which is used to control the power supply, rather than output information obtained at the power supply itself.
  • the controller may be configured to control the output voltage or power of the direct current power supply although preferably the controller is configured to control the electrical current output of the direct current power supply as this method is the most popular and easy to implement. Preferably this is achieved by implementing a voltage loop, that is by measuring voltage on particular tanks to guarantee voltage stability which is achieved by changes in current flowing through tanks.
  • the potential difference monitoring may be implemented according to a number of different system configurations.
  • the monitoring system is configured to monitor a pair of locations in the circuit for each tank connected within the circuit.
  • two or more larger sets of tanks could be monitored together to reduce costs.
  • certain representative individual tanks could be monitored whereas some tanks could remain unmonitored.
  • the current flows through all of the tanks and assuming their construction is similar we can expect an even distribution of voltage across them. Exceptions are monitored by the system and technician intervention may be used in the case of a detected problem so as to return the tanks to the even voltage distribution state.
  • the ideal is to monitor the voltage on all anode-cathode pairs but this is not realistic.
  • each group may be selectively removable electrically from the circuit. This may be achieved by short-circuiting the tanks or by entirely disconnecting them from the series circuit. Whilst these procedures may be effected manually, it is preferred that the system further comprises a tank group isolation device for causing the selective removal of a group of tanks from the series circuit (by short-circuiting or otherwise isolating the tanks).
  • the controller may be configured to operate the group isolation device in response to, for example, a signal from the potential difference monitoring system. Hence the electrical isolation may be effected automatically. Conversely the group may also be reconnected automatically once any problem has been addressed.
  • the monitoring is performed repeatedly during a time period in which the electrolytic deposition of copper occurs. This may occur by frequently "sampling" the output of the monitoring system so as to effect continuous monitoring.
  • the actions of the controller are dependent upon the monitored signals from the tanks and may be combined with other signal data from other systems in order to provide a high degree of precision control.
  • the step of controlling the electrical output of the direct current power supply comprises controlling (and in practice this normally comprising modifying) the electrical output from the direct current power supply such that the monitored electrical potential differences between each pair of locations causes the electrical potential difference between each respective at least one anode and at least one cathode to lie within a plateau region for electrolytic copper deposition. As is known, the plateau region provides a high purity copper deposit at a relatively high deposition rate.
  • the "locations" in the series circuit are typically electrical connections to the power supply bars for the anodes and cathodes of the tanks.
  • the process can be thought of as introducing a "self-repairing" or “adaptive” capability for the electrorefining process. For example if, whilst the traditional current density controlled process is underway, the tankhouse temperature drops during winter (which is frequently reported by tankhouse operators), then a prior art current density controlled system will force the current to flow through the tanks at an unchanged level while the average voltage drop across the tanks will increase even to the level of -1.5V due to increased impedance of the electrolyte at lower temperatures. The consequence of the above is the co-deposition of impurities and deterioration of the copper deposit quality. In comparison when electrical potential difference monitoring is used at the tanks, in the same conditions of a dropping temperature, the voltage measured across the tanks will stay unchanged.
  • This information may be used to indicate that there is not a problem with the electrolytic process itself and therefore the power supply output current may be controlled to drop accordingly so as to adapt to the conditions rather than remain unchanged.
  • the quality of the copper deposit is maintained at a high level and the only consequence will be the productivity drop due to decreasing current density.
  • the manual operators or an automated system will receive the information and have time to fix the problem of the lowering temperature relatively quickly (for example by increasing the power to an electrolyte heating system), while by comparison, in the case of an exclusively current controlled system the copper production batch will be irreversibly damaged.
  • a fault signal is preferably generated by the controller. Such a signal may be acted on in a number of ways either manually or automatically (whereby other automated systems may respond to the signal). If the monitored electrical potential difference between one pair of locations is detected to be substantially lower than that of one or more other pairs of locations then the controller is configured to output a "low voltage fault" signal.
  • the low voltage fault may be indicative of a short-circuit condition which statistically is likely to be represented by a lower potential difference between one pair of locations in comparison with all of the others.
  • the proposed system using electrical potential difference monitoring and corresponding power supply control provides an unexpected and valuable solution to an industry problem with the detection of short-circuits in tanks.
  • the automated control system detects the voltage drop on a given tank, while neighbouring tanks operate normally and the current is flowing normally, the detected condition means that the given tank has a short-circuited anode(s) and cathode(s). This was not previously possible to detect as the voltage control on individual tanks was not an industry practice.
  • the controller is configured to output a "high voltage fault" signal.
  • a signal may be indicative of a poor electrical connection and the magnitude itself of the higher voltage, depending upon the location of the connection, may provide further information upon the nature of the poor electrical connection in terms of whether this is occurring at a single electrode, multiple electrodes or in a more critical part of the circuit.
  • the process also provides a solution to the problem of copper deposit quality management through automated tankhouse management.
  • the automated control system detects a tank with a higher than expected voltage on it, the system may automatically produce an alert which may be used to send operators to inspect the tank.
  • the highest voltage detected could result from bad electrical connections, a local electrolyte temperature drop or any other problem that should be addressed to the benefit to the overall tankhouse productivity.
  • the control system may again increase the voltage on all tanks to the maximum allowed according to the process in question.
  • the process further comprises isolating the tank or tanks corresponding to the said one or more pairs of locations, or isolating a group of tanks containing said tank or tanks, so as to remove them electrically from the series circuit.
  • the "range” in this case may in effect be only a high threshold (having effectively no lower threshold), a low threshold (having effectively no higher threshold) or a specific predetermined range in which a low and high threshold exist, each of which may be realistically passed by operational potential differences in practice according to certain fault or sub-optimal conditions.
  • the control system may be configured to repeatedly (that is, one or more times) perform the steps of:
  • control system may be configured to repeatedly (that is, one or more times) performs the steps of:
  • the electrical output of the direct current power supply is preferably controlled by modulating the electrical potential difference output, which in the cases of the above two alternative repeated methods, may occur by a stepwise ramping.
  • the control according to the above circumstances, or more generally, is typically effected according to a predetermined relationship which may be embodied in a look-up table or database.
  • An algorithm may also be used to achieve this, particularly when embodying empirical or analytical relationships and when including further inputs and outputs to the process (such as information from other systems and the control of other apparatus).
  • the control may seek to minimise a difference between "theoretical" potential values (such as calculated or predetermined values) and actual measured values.
  • a least squares algorithm may be used to achieve this.
  • the step of controlling is therefore preferably performed according to a computer implemented process. This may include some operator intervention between certain steps or following particular signals being generated.
  • the maximisation of automation is also envisaged by the invention which is a general goal of industrial operators. Nevertheless an output of the process may be to generate a schedule of service work for tankhouse personnel such as a maintenance/repair crew.
  • the electrical potential difference between the at least one anode and the at least one cathode within each pair of locations in the circuit is maintained within an electrolytic plateau region for the deposition of copper.
  • the plateau region is within the range -0.27 to -0.55V with respect to the anode.
  • the electrical potential difference between each respective at least one anode and at least one cathode in each tank may be controlled to be -0.4V or less.
  • the invention relates to apparatus and process on an industrial scale.
  • the power supply is adapted to provide a current within the range 10kA to 20kA to the tanks.
  • a further beneficial approach to controlling the power supply output is by providing a filter configured to remove modulations in the potential difference from the power supply, where such modulations have a frequency above a predetermined threshold.
  • the filtering of the output of the power supply is such that only minor modulations in the potential difference from the power supply, having a frequency below a predetermined threshold, are allowed to remain.
  • a beneficial predetermined threshold is about 100kHz, more preferably 50kHz for some power supplies.
  • the predetermined frequency is in the frequency range 100Hz to 1 kHz since unwanted modulations at these frequencies are often present in the power supply output.
  • a further practical improvement to the process which may be enabled by more precise and informed control of the power supply is to use anodes which are configured to have a greater surface area in total than the cathodes. Typically such a total surface area is at least 30% greater, that is a ratio of 1 .3 whereas in present industrial practice the anodes are usually smaller than the cathodes with a ratio being in the range 0.9 to 0.92 (for which see the KGHM monograph; table 6.6.5 page 1026).
  • the anodes may be angled with respect to the width direction of the tank.
  • such anodes and therefore typically the cathodes also
  • Such an angle may be about 45%.
  • different tank geometries may be used instead, including parallelograms and other shapes rather than simple rectangles.
  • the process allows a solution to the problem of "higher yields-time" in copper production.
  • the yield can be increased by 10% to 50% in comparison to traditional current density controlled process without the quality drop of the copper deposit.
  • the present invention may be applied to an electrorefining process or to an electrowinning process with similar benefits.
  • Figure 1 is a schematic representation of apparatus used in association with the examples;
  • Figure 2a shows the series connection of monitored groups of tanks according to an example;
  • Figure 2b shows the series connection of monitored tanks within a group
  • Figure 3 is flow diagram providing a general overview of the method
  • Figure 4a shows a schematic prior art arrangement of electrodes within a tank
  • Figure 4b shows an example inventive arrangement using a tank arranged as a parallelogram
  • Figure 4c shows an example inventive arrangement using a tank with at least a greater width
  • FIG. 5a shows a prior art series connection of groups of tanks
  • Figure 5b shows a prior art series connection of tanks within a group. Description of Preferred Examples
  • FIG. 1 A schematic view of industrial apparatus suitable for performing the present invention is illustrated in Figure 1 .
  • a bath 1 is provided, for simplicity this being illustrated as a single container.
  • this is formed from a number of individual cells or "tanks" electrically connected in series and formed from a polymer material which exhibits good long term resistance to the electrolyte.
  • the electrolyte is illustrated at 2 and has a typical composition used in industrial copper electrorefining processes.
  • First electrodes 3 (shown as solid lines) are provided, formed from copper material to be refined and are arranged to form the anodes within the cells. These take the form of planar sheets and are spaced at regular intervals, hanging vertically within the electrolyte 2.
  • Second electrodes 4 are provided taking a similar form to the first electrodes, again hung vertically, although in this case being formed from either previously electrorefined copper or stainless steel.
  • the second electrodes form the cathodes within each cell and are positioned equally spaced between the anodes, for example at a distance of a few centimetres from the anodes.
  • the anodes and adjacent cathodes may be thought of as "pairs" for gaining an understanding of the apparatus.
  • a current and/or voltage controlled power supply 5 is provided to drive the electrorefining process.
  • Each anode is connected electrically to the power supply via a supply line 6; similarly each cathode is also connected electrically by a supply line 7.
  • An electrolyte system 8 is illustrated. This performs a number of functions including filtering the electrolyte, controlling its composition (by the addition and removal of impurities/agents), maintaining the electrolyte at a predetermined temperature and ensuring the circulation of the electrolyte within the cells.
  • the apparatus is controlled by a controller 9 which is in communication with the electrolyte system 8 and power supply 5.
  • the controller 9 includes a voltage controller VC which monitors the electrical potential difference drop across a number of the anode- cathode pairs as is illustrated at 10.
  • a filter F which is typically a low-pass filter, is provided on one or each of supply lines 6 and 7. Such a filter F may be provided to enhance the quality of deposited copper (metal) by removing high frequency components in the power supply electrical potential difference which are detrimental to the process such as to quality of the deposited copper.
  • the filter F can be realised as a choke connected in series with tanks (playing a role of capacitance) or conductive bars covered with electromagnetic absorber material.
  • Figure 2a illustrates more accurately the electrical arrangement of the tanks when compared with Figure 1 .
  • monitoring links 10 are provided from each group to the voltage controller VC.
  • Such links may take the form of a potential difference measuring device and signalling cable for each tank. The device may be located at the tank or the signalling cable may provide the electrical potential to the voltage controller where it may be monitored internally to the voltage controller.
  • the links 10 may provide electrical potential difference monitoring of groups of tanks or a representative number or selective tanks within each group, the greatest accuracy of monitoring is to provide a specific monitoring link to the voltage controller for each tank in every group such that every tank is monitored when in use.
  • FIG. 2b illustrates one selected group of tanks comprising a certain number of tanks, such as 20, which can be short-circuited using switch S for maintenance or service works while the remaining tanks continue the production of copper.
  • Each tank contains a certain number of anodes and cathodes, for example 20 to 50 of each although there may be typically one additional anode in comparison with the number of cathodes such that an anode is provided at each end of the anode-cathode array.
  • the anodes are connected in parallel with each other, as are the cathodes.
  • the electrical potential difference is measured across each tank and a monitoring signal is communicated via the monitoring link 10 to the voltage controller VC as part of the controller 9.
  • the voltage controller VC as part of the controller 9.
  • Industrial power supplies may be produced using a number of different technologies, including semiconductor thyristor technology and semiconductor MOSFET switches.
  • MOSFET supplies typically two characteristic modulations of the output voltage occur, one in the range of MHz (ex. 5MHz) due to an internal clock and another in the range of kHz (ex. 50kHz) due to internal switching.
  • the voltage modulation comprises harmonics of 50/60Hz and is in the range of 100Hz to 1 kHz.
  • a filter is provided to improve the stability of the power supply then the type of filter chosen is dependent upon the power supply.
  • the optional low-pass filter F should typically have a cut-off frequency below 50kHz and this depends on specific construction of power supply. In the case of thyristor based power supplies this cut-off frequency should be even in the range of 100Hz-1 kHz as those low frequency components in such power supplies have amplitudes higher than the plateau range for copper.
  • the voltage control system VC continuously samples the voltage data received from each of the tanks in the groups and monitors for behaviour indicative of various disadvantageous effects within the process.
  • the voltage control system is typically a computerised system which monitors electrical potential data signals obtained from the links 10 and analyses this data to detect certain behaviours.
  • the voltage control system algorithm may monitor for individual cell potential differences being or drifting out of parity with that of other cells. For example, if the measured signals from one particular tank in a group show a rapid drop in potential difference then a low voltage fault condition is detected. In such a case the low voltage drop across the tank may be caused by an imminent or actual short-circuit between the electrodes in a tank (which may occur because of dendritic growth of the copper deposit).
  • a fault signal may be indicated to an operator.
  • the short-circuit will produce an overall reduction in the combined impedance of the tanks circuit, which would ordinarily cause the power supply to respond in a particular manner (depending upon whether it was attempting to maintain a target current or a target overall potential difference).
  • Knowledge of the cause of the change in impedance allows the voltage controller VC to control the power supply to make an appropriate adjustment to the overall output target potential difference to ensure that the remaining cells continue to operate at their optimum electrical potential difference.
  • the magnitude of the overall power supply output potential difference is reduced accordingly.
  • the controller may be operated to take each of the tanks which contains the short-circuit out of the process temporarily by closing the switch S to short-circuit the relevant group of tanks or otherwise isolate it from the rest of the system whilst the process continues.
  • the voltage controller reduces the overall output potential difference according to the number of series-connected cells in the group so as to maintain the correct operational voltage of each of the remaining tanks in the other groups.
  • a technical team may be assigned to fix the problem before the tank group is brought back into the circuit and the voltage of the power supply increased accordingly once more.
  • the voltage controller VC monitors the magnitude of the electrical impedance in the tank in question and makes an appropriate adjustment to the output voltage of the power supply. In this case a high voltage fault is detected and a high voltage fault signal is produced.
  • the group of tanks in question is again taken out of the circuit as in the case of the previous example whilst the problem is fixed. Again, the power supply output potential difference is controlled accordingly.
  • the monitoring may not only include the magnitude of potential differences but also their rate of change and cumulative effect.
  • the monitoring system may include a proportional-integral-derivative type control for example.
  • Each of the above fault conditions is essentially an electrical condition substantially unrelated to other conditions within the tanks.
  • a change in the monitored electrical potential difference on the population of tanks, and the current may be indicative of another process condition becoming sub-optimal, such as temperature, electrolyte chemistry, electrolyte leakage.
  • the voltage controller VC may take information from other monitoring apparatus within the tanks.
  • An example of such information is the electrolyte temperature. If the electrolyte temperature drops, the monitored electrical potential difference remains substantially the same and the current drops, then this may indicative of a seasonal drop in external temperature. Temperature has an effect upon the process current density.
  • the monitored electrical potential difference provides important information regarding the electrolytic process.
  • the voltage controller is operative to control the output of the power supply and it will be understood that this may be in terms of the output current or the output electrical potential difference.
  • the voltage controller is part of the general system controller 9 which controls other aspects of the system such as handling of the electrolyte, heaters to control the electrolyte temperature and so on.
  • Various implementations of the voltage controller are envisaged including ones in which a computer system makes adjustments in accordance with data in a database which includes data representative of all possible operational conditions so as to cause an appropriate action by the voltage controller.
  • the voltage controller may alternatively use one or each of empirical or analytical predetermined relationships and logic according to a voltage controller algorithm in order to ensure that the desired behaviour is effected.
  • FIG. 3 illustrates a general overview of the novel electrorefining process.
  • the anodes 3 are manufactured from a material which it is desired to be refined.
  • cathodes 4 are obtained (these may have been used in a previous electrorefining cycle).
  • the anodes and cathodes are arranged in their cells within the tank 1 and are connected electrically to the power supply 5.
  • the electrolyte 2 is then introduced into the tank and the electrolyte system 8 is operated by the controller 9 so as to establish a flow of electrolyte within the cells at the appropriate temperature, which may be room temperature.
  • the controller 9 (including voltage controller VC) operates the power supply 5 so as to deliver current (power) in such amount to keep each tank voltage within desired operational limits.
  • the "operational limits" include keeping the electrical potential difference just below or within the plateau region. Where the power supply has received filtering to reduce high frequency potential difference components then a greater “rms” or average operational potential difference may be used.
  • Monitoring of the process conditions is performed throughout the process by the controller 9 and individual tanks are at least voltage monitored using the monitoring links 10. Once the process has stabilized the refining proceeds at step 600. This involves the continuous monitoring of tank voltages and the application of a voltage control on the power supply to control the voltages experienced at the tank electrodes within the predetermined operational limits. Optionally a pulsed electrorefining and/or periodic voltage reversal may be applied.
  • step 700 the electrical power supply is terminated, the eroded anodes are removed (unless they contain sufficient material for reuse) and the cathodes (containing the refined copper) are washed.
  • step 800 the cleaned cathodes are then subjected to mechanical removal of the high purity copper which has been deposited. If the cathode is a steel one then the copper is removed from its surface; if the cathode blank is a copper one then it is harvested as a whole.
  • Figure 4a is a schematic representation of typical prior art apparatus (tank) and Figures 4b and 4c are schematic representations of novel designs of apparatus (tank) used in either the electrorefining or electrowinning of copper.
  • the tank 1 1 is filled with electrolyte and is outfitted with electrically conductive bars 12a and 12b (anodic and cathodic respectively).
  • Anodes 13 are in electrical contact with the bar 12a and cathodes 14 are in electrical contacts with bar 12b.
  • the surface areas of the anodes and cathodes are comparable and their ratio is close to 1.
  • the surface ratio of anode to cathode is greater than 1 which is realised through positioning the electrodes at an angle as in Figure 4b (where similar components to Figure 4a are illustrated with primed references).
  • Figure 4b where similar components to Figure 4a are illustrated with primed references.
  • FIG. 4b A prior art rectangular tank may be used for this or a new tank geometry used (such as a parallelogram in plan view as shown in Figure 4b).
  • the anodes are made larger than their prior art counterparts whereas the cathodes remain unchanged in size as is shown in Figure 4b.
  • larger volume tanks at least in width
  • Figure 4c where similar components to Figure 4a are illustrated with double-primed references).
  • the tank is larger in volume, assuming a similar depth, and may be rectangular with a similar aspect ratio to Figure 4c.
  • the anodes are larger and the cathodes remain unchanged.
  • the present invention demonstrates that control of voltage on a representative set of tanks and control of the power quality supplied to tanks (including accurate control over the voltage drop across the tanks and the optional removal of modulations in the power supply voltage) allows for operation with the highest possible current densities whilst maintaining or improving the copper deposit quality.
  • a simple example of a control algorithm could aim to keep all voltages across the tanks to 0.4V or less:
  • Step 1 If at least one tank reports the voltage level above 0.4V then drop the overall voltage on the power supply output by the value of 1V (or drop the current by the value of 1A);
  • Step 2 repeat Step 1 until all voltages on all tanks are below or equal 0.4V
  • Step 3 send a signal or report about the faulty tank to the operator (use) for adopting a maintenance/repair procedure or otherwise process the signal using a tankhouse maintenance/repair system.
  • Some typical fault conditions which may be detected by monitoring the voltage from all tanks (distribution of the voltage) and the current flowing through all tanks include:
  • HV-LC check electrical connection in the tank, temperature drop, electrolyte leakage or passivation
  • LV-LC check the tank, major issue with short-circuit and electrolyte leakage in series of tanks.
  • the power supply can be of a type which is either voltage or current controlled (which may be called galvanostats or potentiostats respectively) but the variations of current or voltage at the output during normal "steady state" operation should be minimized in such a way that the voltage measured on each tank is below the maximum value of the plateau for copper deposition in given electrochemical conditions (anode and cathode material, electrolyte composition, temperature etc.).
  • low, medium or high frequency noise is always present in industrial power supplies.
  • the noise is in the range 100Hz to 1 kHz in thyristor based power supplies (low).
  • the noise is in the range of 50kHz (medium) and 5MHz (high) in case of MOSFET based power supplies.
  • Low frequency noise has a big impact on the deposition process; medium frequency noise has a lower impact, and the high frequency noise has the lowest impact on the deposit quality. Consequently, filtering is most beneficial for thyristor power supplies. This means that it is practically impossible to use a 100% potentiostatic process.
  • High frequencies can be filtered by so called low-pass filters enhancing the quality of the power supplied to the process and consequently the quality of the deposit and/or the yield.
  • voltage frequency filtering should be used when the power supply itself cannot guarantee voltage stability at the copper electrolytic plateau upper limit (for a given process) for frequencies below about 100kHz.
  • anodes are larger (bigger surface) in comparison to cathodes.
  • This can be realised through the placement of electrodes at a certain angle such as 45 degrees when prior art tanks are used and the cathodes are of a conventional size. This result has been confirmed experimentally. New larger tanks can be implemented also, which the applicant has confirmed experimentally.
  • the cathodic current effectiveness may reach values of greater than 100% which is related to the participation of ions Cu+1 in the process (the calculation assuming Cu+2). This fact is known to laboratory experiments but for the first time is observed in the industry due to the use of voltage monitoring and control, together with appropriate high quality power supplies. Experimentally we have measured values in the range of 104% to 107%. The industry strives for higher current effectiveness as this is directly related to power economy and product purity.
  • a further practical consequence of voltage monitoring and control is that the copper deposit has high quality, generally higher than in prior art processes.
  • the surface is observed to be of a fine crystalline structure and the material is of high purity. In our industrial scale tests, all deposits had a purity of >99.97%.
  • An electrochemical tank made from polyvinylchloride is used.
  • Four copper anodes with the dimensions 415x315mm are used, interleaved with three copper cathodes (blanks) with the dimension 405x313mm (the dimensions relate to working surface in electrolyte).
  • a commercially available MOSFET based, current controlled power supply is used with the ability to supply up to 500A of DC current (Munk A1 D500/500).
  • the power supply output is connected to the tank anode and cathode bars using a 3 metre long low impedance coaxial cable (Munk MC095, http://www.munk-nl.com/en/products/34) via a filter.
  • the filter choke is made as a coil of insulated wires wound on a ferromagnetic core, and plays a role of a passive inductor.
  • the filter was chosen in such a way to guarantee the oscilloscope measured values of anode to cathode potential, for signal components below 50kHz to be within the range of 0.2V to 0.4V i.e. within the range of the plateau or below.
  • Each pair of anode/cathodes is connected via coaxial cable and via four analogue input modules to the voltage control unit composed of a commercially available driver (Siemens PLC S7-1200) outfitted with said four analogue input modules and one analogue output module being connected to the said power supply via Munk ECM Remote Sense Card control board performing two functions: the remote sensing of gap-voltage and power supply current regulation to keep the gap-voltage (the process voltage i.e. the tank voltage or anode/cathode voltage depending on implementation) on the preset value.
  • the gap voltage is calculated by the driver (Siemens PLC S7-1200) as the maximum voltage among 4 connected pairs of anode/cathode.
  • the power supply is connected via RS232 communication cable to the PC computer with Munk VPC software allowing definition of the gap-voltage and registering actual values of current and Amp-second integral.
  • the driver (Siemens PLC S7-1200) is connected with a PC computer and displays anode/cathode voltage information and the highest value is transmitted to the ECM Card via the analogue output module on real time basis.
  • the power supply regulates the current in such a way to keep the preset value (maximum anode/cathode voltage) at an unchanged level.
  • the operator can see which anode/cathode pair has actually the highest voltage and can adjust electrical contacts of other pairs to increase the overall current flowing through the tank (by moving, shaking and/or cleaning electrical contacts between the tank bars and anode/cathode bars).
  • the tank is filled with an electrolyte of the following composition: 46 g/dm 3 Cu, 180 g/dm 3 H2S04 and 0.1 g/dm 3 Fe, 0.3 g/dm 3 Sb, 0.03 g/dm 3 Bi, 5 g/dm 3 Ni, 10 g/dm 3 As, 0.00015 g/dm 3 Ag, 0.001 g/dm 3 Ba, 0.4 g/dm 3 Ca, 0.001 g/dm 3 Cd, 0.03 g/dm 3 Co, 0.02 g/dm 3 Mg, 0.0004 g/dm 3 Mn, 0.007 g/dm 3 Pb and 0.001 g/dm 3 Pd.
  • the electrolyte composition resembles a typical industrial electrorefining electrolyte as, for example used, in the prior art copper electrorefining process at a KGHM facility.
  • the process is conducted at an electrolyte temperature of 60 Celsius, the electrolyte flow is set to 2 litres/minute, the voltage control (gap-voltage) in the power supply is set to 0.4V using VPC management software delivered with the power supply and the electric charge transferred during the process is measured (amp-second).
  • the oscilloscope measured values of potential, for signal components below 50kHz are within the range of 0.2V to 0.4V i.e. within the range of the plateau and below while the unfiltered components at the power supply output are within the range of -0.1V to 1 .4V.
  • the copper deposit After 60 hours of electrorefining the copper deposit was removed, dried, weighed, quality checked by a certified third party laboratory and the cathodic current effectiveness calculated. A stationary current density of approximately 255 A m 2 at the cathode was achieved after about 1 hour. The obtained cathode copper has a purity higher than 99.996%. Having compared the deposited copper mass with the theoretical mass of copper that should be deposited (using Faraday's law), it is found that the current efficiency of the process is higher than 107%. The copper deposit has a smooth, fine crystalline surface without dendrites.
  • Example 3 The experiment was conducted in the same conditions as in Example 1 except with the electrolyte flow being set to 4 litres/minute (two times higher than in Example 1 ). A stationary current density of approximately 265 A m 2 at the cathode was achieved after about 1 hour. The obtained cathode copper has a purity higher than 99.98%. Having compared the deposited copper mass with the theoretical mass of copper that should be deposited (using Faraday's law), it is found that the current efficiency of the process is higher than 104%. The copper deposit had smooth, fine crystalline surface without dendrites. This demonstrates that good deposition may be obtained under different electrolyte flow conditions. By comparing to the previously described industrial practice in similar physic-chemical condition where current density used is in the range 220Am "2 to 235 Am "2 the presented invention allows for a yield increase from 12% to 20%. Example 3
  • the experiment was conducted in the same conditions as in Example 1 except for the size of the anodes and the placement of anodes and cathodes.
  • the anodes used had a larger individual surface area than the cathodes and were placed with angle at about 45 degrees to the tank walls (as illustrated in Figure 4b).
  • the surface ratio of anode/cathode was 1 .4.
  • a stationary current density of approximately 305 A m 2 at the cathode was achieved after about 0.5 hour.
  • the obtained cathode copper has a purity higher than 99.979%. Having compared the deposited copper mass with the theoretical mass of copper that should be deposited (using Faraday's law), it is found that the current efficiency of the process is higher than 99%.
  • the copper deposit has a smooth, fine crystalline surface without dendrites.
  • the use of the larger anodes which are arranged at an angle with respect to the tank allowed for a significantly higher current density upon the cathodes, providing greater productivity.
  • the experiment was conducted in the same conditions as in Example 1 except that the electrolyte flow was set to 0 litres/minute (static), the cathode dimensions were reduced to 300mm x 385mm and the electrolyte temperature was dropping during the process from initial 60 Celsius to the final 20 Celsius at the end of the process.
  • a stationary current density of approximately 274 A m 2 at the cathode was achieved after about 1 hour at 60 Celsius, and the stationary current density of approximately 1 15 A/m 2 at the cathode was achieved after about 60 hours, at 20 Celsius at end of the process. It should be noted how the current density drops significantly as a result of the temperature reduction.
  • the obtained cathode copper has a purity higher than 99.97%. Having compared the deposited copper mass with the theoretical mass of copper that should be deposited (using Faraday's law), it is found that the current efficiency of the process is higher than 97%.
  • the copper deposit has a smooth, fine crystalline surface without dendrites.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)

Abstract

La présente invention se rapporte à un appareil industriel permettant le dépôt électrolytique du cuivre, ainsi qu'à un procédé d'utilisation de l'appareil. Une pluralité de cuves de dépôt sont fournies, chacune étant destiné à contenir un électrolyte et ayant au moins une anode et au moins une cathode positionnées dans l'électrolyte lors de l'utilisation. Une alimentation électrique en courant continu fournit un courant électrique aux cuves, qui sont raccordées en série, de sorte à commander le procédé de dépôt électrolytique du cuivre. Un système de surveillance des différences de potentiel surveille les différences de potentiel électrique respectives à travers les cuves, et un dispositif de commande module la puissance restituée de l'alimentation électrique en courant continu en fonction du système de surveillance des différences de potentiel.
PCT/EP2013/073800 2012-11-14 2013-11-14 Appareil industriel adaptatif et procédé permettant le dépôt électrolytique du cuivre WO2014076169A1 (fr)

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GB201220507A GB2507972A (en) 2012-11-14 2012-11-14 Adaptive Industrial Apparatus and Process for the Electrolytic Deposition of Copper

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CN111091291A (zh) * 2019-12-16 2020-05-01 肇庆市高要区华锋电子铝箔有限公司 电子铝箔化成质量监控方法、装置、系统和电子设备
CN117702198A (zh) * 2024-01-09 2024-03-15 深圳市瑞盛环保科技有限公司 一种电解铜提炼电流控制系统及方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1221578A (en) * 1965-11-11 1971-02-03 Knapsack Ag Apparatus for measuring the current at the individual electrodes of electrolytic cells
US4430178A (en) * 1982-05-24 1984-02-07 Cominco Ltd. Method and apparatus for effecting current reversal in electro-deposition of metals
WO2001088225A1 (fr) * 2000-05-16 2001-11-22 Metallic Power, Inc. Electrolyseur et son procede d'utilisation
US20030066759A1 (en) * 2001-08-15 2003-04-10 Hardee Kenneth L. Anodic protection systems and methods
WO2005001164A1 (fr) * 2003-06-20 2005-01-06 W2W Llc Reglage de puissance pour un appareil electrique de traitement de l'eau
US20060213766A1 (en) * 2004-03-17 2006-09-28 Kennecott Utah Copper Corporation Wireless Monitoring of Two or More Electrolytic Cells Using One Monitoring Device
WO2012020243A1 (fr) * 2010-08-11 2012-02-16 Duncan Grant Appareil destiné à être utilisé en électroaffinage et en électroextraction

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1221578A (en) * 1965-11-11 1971-02-03 Knapsack Ag Apparatus for measuring the current at the individual electrodes of electrolytic cells
US4430178A (en) * 1982-05-24 1984-02-07 Cominco Ltd. Method and apparatus for effecting current reversal in electro-deposition of metals
WO2001088225A1 (fr) * 2000-05-16 2001-11-22 Metallic Power, Inc. Electrolyseur et son procede d'utilisation
US20030066759A1 (en) * 2001-08-15 2003-04-10 Hardee Kenneth L. Anodic protection systems and methods
WO2005001164A1 (fr) * 2003-06-20 2005-01-06 W2W Llc Reglage de puissance pour un appareil electrique de traitement de l'eau
US20060213766A1 (en) * 2004-03-17 2006-09-28 Kennecott Utah Copper Corporation Wireless Monitoring of Two or More Electrolytic Cells Using One Monitoring Device
WO2012020243A1 (fr) * 2010-08-11 2012-02-16 Duncan Grant Appareil destiné à être utilisé en électroaffinage et en électroextraction

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