JP2014533778A - Process for industrial copper electrorefining - Google Patents

Abstract

A method of copper electrorefining is disclosed. The method includes aligning at least one anode of a smelted copper material in contact with an electrolyte solution and aligning at least one cathode in contact with the electrolyte solution. The anode and cathode are electrically connected to a power source, and the power source is operated under potential control conditions. The potential at the cathode is -0.30 V to -0.55 V with respect to the copper material at the at least one first electrode, thereby causing electrorefined copper deposition at the at least one second electrode. The method also includes constant voltage pulse electrolysis (PPE) and periodic reversal potential (PPR), for example to purify copper deposits having a controllable structure with respect to roughness or porosity. An apparatus for performing potential controlled electrolysis is also disclosed.

Description

  The present invention relates to a novel method for copper electrorefining using potential control which has application in the copper industry.

  According to the statistical data described in Polish Patent Application No. 396693, the global annual production of electrolytic copper obtained by the copper electrorefining method was 15,000,000 tons in 2009. Furthermore, W.W. G. Davenport, M.M. King & M. Schlesinger, entityd “Extractive Metallurry of Copper”, published by Elsevier Science Ltd. From the data presented in a research paper by Oxford in 2002, it is known that high purity copper with a copper concentration of more than 99.90% is available as a result of electrorefining.

  Both the quality of copper and the market price of copper depend on its mechanical, electrical and thermal properties, which vary with impurity content. The electrorefining process allows the removal of impurities from copper that cannot be removed by an alternative process of fire-refining. Allows recovery of other noble metals such as gold, silver, platinum, nickel and selenium.

In known methods, an anode made of impure copper obtained from a dry refining process or from other sources such as recycling, scrap, etc. is subjected to electrorefining. During the anodic process, the copper is dissolved and the aqueous solution undergoes the following basic reactions:
Anode: Cu ⁰ = Cu ²⁺ + 2e
(In practice the reaction is rather more complex).

Pure copper or acid resistant steel (stainless steel) sheet has the following basic reactions ::
Cathode: Cu ²⁺ + 2e = Cu ⁰
Provides a cathode on which metallic copper is deposited.

An example of conditions for electrorefining methods in KGHM Polish Copper Globe Copper Smelter and Refinery is in PhD thesis by Olimpia Gladysz, University of Wroclaw Chemistry 6 According to the above information source, an impure copper sheet (copper sheet refined using a dry refining process having a size of 1 × 1 × 0.05 m) undergoes dissolution of the anode in the electrorefining process. A pure copper sheet (obtained using an electrolysis method and having a thickness in the range of 0.001 to 0.003 m) on which metallic copper is deposited functions as a cathode. The anode is suspended in an electrolytic cell filled with an electrolyte consisting of copper ions, sulfuric acid, organic additives and chloride ions. A typical electrolyte composition is shown in Table 1. Concrete tanks covered with lead and newer ones made of resin concrete reinforced with glass fiber rods are used to contain the electrolyte. In contrast to concrete tanks, resin tanks are resistant to sulfuric acid. This is also a dielectric and a good thermal insulator. A cathode “pad” in the form of a sheet is suspended between the anodes and connected to a power source. There are 30-60 pairs of anodes and cathodes connected in parallel to each cell.

According to the same reference, a thin-layer electrolyte flowing through a bath (approximately 0.02 m ³ / min) at a continuous, constant temperature and flow pressure is a necessary condition for performing an appropriate electrorefining process. . The electrolyte flow rate is typically in the range of 0.01 to 0.03 m ³ / min, which allows complete replacement of the electrolyte every 4 to 6 hours. To do this, this specialized equipment was used: acid resistant pumps, heaters, polyethylene fabric covering the tank. Maintaining a suitable high temperature (60-65 ° C.) is also very significant in the electrorefining process. During the electrorefining process, ions of impurities such as As, Bi, Co, Fe, Ni and Sb are constantly dissolved in the solution from the anode. In order for the electric refining process to be performed appropriately, the concentration of these elements in the electrolyte after refining is as follows: As-20 g / dm ³ , Bi-0.6 g / dm ³ , Fe-2 g / dm ³ , It is believed that Ni-25 g / dm ³ and Sb-0.7 g / dm ³ should not be exceeded. In order to reduce the concentration of impurities, the impure refining electrolyte is preferably removed and replaced by sulfuric acid. In the 1990s, a new system for copper electrorefining was put into operation-this ISA system, along with many places (Townsville-Australia, Copper Range Co.-USA, Norddeutsche-Germany), KIDD SYSTEM (Kidd Creek-Canada) Was introduced. In these systems, electrorefining was performed on a multipurpose cathode made of acid resistant steel that has been durable for over 20 years. The copper layer deposited in a 5-8 day cycle was mechanically removed and the cathode was returned to the cell. Despite the use of higher current densities reaching up to 340 A / m ² , the metallic copper obtained using this system had a high quality. The current efficiencies of both processes are comparable and are between 95% and 97%. The potential difference between the anode and cathode is comparable and equals about 0.3V. Advantageous effects, including quality, include the following factors: shorter time of cathode deposition growth in the cell, vertical suspension with strict accuracy, minimum number of shorts, and process control and parameter adjustments made Achieved through automation. A permanent acid resistant cathode system does not require cathode pad preparation which reduces production costs. Currently, most newly manufactured and modernized refining machines are believed to use this system.

  According to the data shown above, which is representative of industry practice, the copper electrorefining process is performed under constant current conditions (constant current conditions). This means that the method is performed at a “forced” rate / speed of copper deposition, ie at a constant current density. However, it should be added that the current density on individual cathodes in an industrial bath that affects the quality of the resulting copper can vary significantly. The cathode current density is the most important economic parameter of the copper electrorefining process. Most research contributed to the electrorefining process involves improving the quality and purity of the cathode deposition. Research is particularly focused on how to avoid the formation of dendrites on the cathode, which can cause a short circuit between the anode and the cathode, thereby maintaining maximum cathode current density. Research on how to avoid passivation and corrosion pits has also been undertaken.

  For economic reasons, the copper electrorefining process should proceed at the highest current density while at the same time maintaining the proper (microcrystalline) structure and chemical composition of the cathode. The ISA technology used today allows the maximum current density of the constant current or “current controlled” electrolysis process to be realized. That said, there is a continuing need to develop electrical smelting technology in the copper industry to produce high quality copper products at lower costs. It is the content of dealing with these problems devised by the present invention.

  According to a first aspect of the invention, arranging at least one anode of a smelted copper material in contact with an electrolyte solution, arranging at least one cathode in contact with the electrolyte solution, an anode and a cathode Electrically connecting the power source to the power source, operating the power source under controlled potential conditions to be between at least a portion of the application of the conditions, and the potential at the cathode to the copper material at the anode We provide a process for the electrorefining of industrial copper comprising the steps of -0.30 V to -0.55 V, thereby producing a volume of electrorefined copper at the cathode.

  We understand that, unexpectedly and in full contrast with industrial practice, the use of potential-controlled conditions during the industrial electrorefining of copper can cause significant gains. did.

According to a second aspect of the invention, we have a container for holding an industrial electrolyte;
At least one first electrode made of a copper material placed and refined to be used in contact with the industrial electrolyte in a container;
At least one second electrode positioned to be used in contact with the industrial electrolyte in the container;
When used for each of the at least one first electrode and at least one second electrode, during at least part of the application of the condition, the potential at the at least one second electrode is at least 1 Under potential control conditions such that the deposition of electrorefined copper at at least one second electrode occurs from -0.30 V to -0.55 V relative to the copper material at one first electrode. An industrial copper electrorefining system including a power source that is electrically connected.

  Typically, the device according to the second aspect is adapted to perform the method according to the first aspect of the invention.

  As explained above, the Cu industry is currently conducting a copper electrorefining process using current control. Of course, in small scale laboratory conditions, in principle, any electrolysis can be performed in either a current controlled or potential controlled configuration. Electrochemical processes are often classified by the potentiostat, galvanostat or rectifier output signal used. Furthermore, the dc current and ac current electrochemical processes are distinguished there. In the special case where the applied signal is a rectangle (waveform), the electrochemical process is called “constant current” or “constant voltage” when a constant current or a constant potential is applied to the electrodes, respectively. However, it is well known that, particularly in industrial environments, the current distribution at the electrorefining electrode is not uniform and can vary by more than 50% of the average current density depending on the cathode site. Furthermore, the current density varies between the cathodes in one multi-electrode electrolysis cell. Thus, in this description, apart from these widely used terms, we use the more general terms “composite form current” (CFC) and “composite form potential” (CFP). These terms are described in Boyko F. K. and Ptitsyna Ye. V. Industrial power engineering-2 (1996) pp. 23-26) such signals with or without constant components as current and potential changes in complex form, adjustable frequency, periodic current reversal (PCR) or (various amplitudes of impulses, pulse ratios and Signals applied at all types of electrodes are described, including pulse electrolysis (PE) current (with period).

  Thus, preferably when practicing the present invention, controlled potentials include the application of complex forms of potential.

  If the current is controlled, the electrode potential cannot be controlled, but time (and electrode / electrode / diffusion) due to diffusion of special electrochemical process mechanisms and kinetics (eg, charge transfer, chemical reaction of electroactive species, electroactive species). At a point in space such as the electrolyte interface).

  When the potential is applied in a controlled manner, the current cannot be controlled, but varies with time due to the mechanism and kinetics of the electrochemical process. Such a potential is supplied by a power source that ensures that the applied potential is substantially independent of the current drawn from the power source (within the normal operating limits of the device).

  Since current (or more precisely current density) is a measure of the electrochemical process, there are two fundamentally different processes. In contrast, potential is the driving force for electrochemical processes that are directly related to concepts such as the free enthalpy of electrochemical reactions.

  If a controlled current is applied, the process proceeds at a well defined rate (but no control of the electrode reaction). This is why current control has been used exclusively in the industrial electrorefining of copper. When a controlled potential is applied, the electrode process is well defined (for example, electrodeposition of copper ions), but the rate varies with process conditions (temperature, copper concentration, etc.).

Modern Electroplating, Fifth Edition, Edited by Mordecha Schlesinger and Milan Paunovic, 2010 John Wiley & Sons, Inc. p. 6 “If an external current greater than the limit current i _L is forcibly applied to the electrode, the double layer is further charged and the electrode potential is reduced until some other process other than the reduction of M ^{z +} is changed. As described, “changes can occur”, in potential controlled electrolysis, the product will be purer than under current controlled conditions.

  Therefore, in the case of industrial copper electrolysis using current control, other processes such as water decomposition, ie hydrogen generation reaction, may occur as a result of potential changes. On the other hand, using the novel, potential-controlled process described in this invention, the cathode potential is controlled and selected in such a way that the only occurring process is copper electrodeposition. In this way, a purer cathode copper with higher current efficiency can be obtained.

It should be understood that the industrial electrorefining process in which current-controlled electrolysis is used is performed at some conditions, ie, some of the maximum cathode current density that can be obtained at copper ion concentration, temperature, electrolyte flow, etc. It is. The maximum current density is called the “limit current density” and Filzwiser, K.M. Hein, and G.H. Mori, JOM, 2002 April pp. According to 28-31, the value of _{i L} used in industrial conditions is about 800A / ^{m 2,} in natural convection conditions, can reach 2000A / ^{m 2} Mademo. In the industrial refining machine, only cathode current densities of up to 350 A / m ² are used. This means that the industrial copper electrorefining rate is an activation (charge transfer) control step. This activation control is often cited as a necessary condition for industrial electrorefining.

  Very importantly, the reason for using such a low cathode current density in the constant current (or more generally current controlled) industrial electrorefining cited above is the refining machine currently used. The increase in current density leads to the formation of nodular and dendritic structures at the cathode, and ultimately due to the copper powder being produced at a current density close to the limiting current density. There are all features that reduce the quality of the cathode copper and reduce the current efficiency of the copper electrorefining process. One of the main problems in copper electrorefining is a short circuit between the anode and cathode due to the growth of dendrites on the cathode.

  We have found that all these phenomena can be avoided if a potential controlled process is used. This step can be performed at a limiting current density (eg, under natural convection conditions) with very high current efficiency, and high purity copper deposited on the cathode (greater than 99.95 wt%, more preferably 99.95%). Produces a very smooth, fine crystalline structure with (> 99 wt%). Thus, contrary to the general wisdom now commonly held in the industry, as shown by the present invention, and particularly in the examples described below, copper electrorefining is achieved by using potential control. Can be performed under limited conditions.

  The use of potential controlled electrorefining allows the application of a negative cathode potential than is found in known refining machines (under current control). The applied potential can be in the range of -0.30V to -0.55V, while preferably the range used is -0.35V to -0.55V, more preferably -0.40V. ~ -0.55V. In contrast, the refiner uses a potential of about -0.3V.

The process of constant voltage copper deposition has been largely ignored in applied electrochemistry research. In most cases using constant voltage, the results of the study are about 6 g / dm ³ Cu, 0.6 g / dm ³ Ni and 0.5 g / dm ³ As, and Sn, Bi, Sb, Pb, Published in 2007 on selective deposition of copper and other metals from synthetic solutions simulating industrial electrolytes from Bor in Serbia containing trace amounts of other metals such as Fe. Giannopoulou and D.M. As shown in the work of Panias (Minerals Engineering 20 (2007) 753-760), the use of potential control has been limited to the process of electrowinning (not to mention electrorefining). It was.

  A study was conducted on a copper cathode using an anode formed of a titanium mesh covered with platinum. The results of this study showed that copper can be deposited in an electrolytic process in the form of an impure cathode. The main impurities of copper deposited on the cathode are arsenic, which reacts with copper to form copper arsenide, and bismuth and antimony.

  A novel method of constant voltage copper electrowinning is shown in Polish patent application number PL396669. In addition, the range of potentials that makes it possible to obtain copper powder in an electrodeposition process from an industrial electrolyte used in the copper industry is published in 2009 (Journal of Electrochemical Chemistry 633 (2009) 92; 637 (2009) 50). A. Lukomska, A .; Plewka P.M. It is determined in the article by Los, PCT patent application number PCT / PL2010 / 00000022.

  Electrowinning is a completely different concept from electrorefining with a separate purpose. There remains a need to provide an industrial electrorefining process to achieve higher cathode current density while maintaining high (commercial) copper purity and its microcrystalline structure. The above problems associated with current controlled industrial electrorefining have been unexpectedly solved by the present invention.

  Advantageously, the process parameters used in the present invention are very close to industrial electrorefining, particularly those currently used on the same basic substrate, i.e. the electrolyte and the anode are new potential controlled. Used in electric refining process. The advantage of the new process lies in the control of the cathode potential, the process limit current can be reached, and with the given exemplary limit current density above, the cathode current density is current controlled. (Eg constant current) can be about 3 to about 5 times higher than in the electrorefining process. The production of cathode copper is 3-5 times faster than current, which can result in a substantial increase in production capacity of existing copper refiners and / or a reduction in production costs per kg of copper, This is a great commercial advantage.

  As described above, the novel potential controlled electrorefining process will result in higher current efficiency and better purity of greater than 99.95%, and more preferably greater than 99.99% Both efficiency and purity are related to the more selective nature of cathodic potential controlled electrolysis, which results in the absence of a competitive electrochemical cathode process. Unlike the current controlled process currently used in the industry, the potential controlled process at high current density provides a compact copper layer with a microcrystalline structure free of nodules and dendrites. This is a very important advantage of the present invention since any modification of existing copper process technology can be extremely expensive. For example, if it is necessary to use a different electrolyte or / and electrode, this is very expensive and complicated to do on a commercial scale.

Beukes, N.M. T.A. and Badenhorst, J.A. Copper electrification: theoretical and practical design. Hydrometallurgy Conference 2009, The Southern African Institute of Mining and Metallurgy, 2009, pp. According to 213-240, there are three main ways to increase the current density of the cathode in an existing (current controlled process) copper smelter:
Cell design optimization,
Using various types of forced convection,
Periodic current reversal.

  The present disclosure presents the purpose of this development within the art and, notably, does not consider moving away from the current control process.

  The novel potential-controlled copper electrorefining process according to the present invention does not require either “optimization of cell design” or “use various types of forced convection”, and very high cathode current density and Obtain very good quality and very good purity copper. Another important advantage of potential controlled electrolysis is that the application of further cathode potential minimizes the step of oxidation of the deposited copper by iron (III) ions, and as a result this reduces the concentration of iron in the cathode copper And is associated with the fact that the current efficiency of the electrorefining process can be improved.

  The most important advantage of the potential controlled electrorefining process compared to the copper electrowinning process is that the copper anode dissolution proceeds with negligible polarization (overvoltage) of about 10 mV. Thus, the cathode potential is controlled very accurately in the electrorefining process. The very high overvoltage and complexity of the anode process makes potential control difficult in electrowinning processes that are much more difficult to do on an industrial scale.

  Although a constant potential can be applied during electrorefining, it is conceivable to adjust one or more of the magnitude and polarity of the potential. Such adjustment controls the resulting structure of the deposited copper.

  For example, the potential can be adjusted as a rectangular wave form having a potential magnitude at the cathode between -0.30V and -0.55V. Further, for example, many cathodic pulses in the range of 3 to 300 are applied, each having a substantially constant potential in the range of −0.30 V to −0.55 V with reference to the copper material at the anode, And constant voltage pulse electrolysis (PPE) conditions, each having a duration of between 5 and 18000 seconds, the pulses being separated in time by an open circuit break, each having a time in the range of 0.1 to 100 seconds Can be applied. A cathodic pulse having a potential in the range of −0.30 V to −0.55 V with reference to the copper material anode is applied for a period in the range of 5 to 18000 seconds, and +0. An anodic pulse in the range of 05V to + 0.60V, whereby the duration of the anodic pulse is at least 50% shorter than the cathodic pulse, and the sequence formed by the cathodic and anodic pulses is repeated 3 to 30 times It is also conceivable to apply typical reverse potential (PPR) conditions. It is noted here that multiple pulses (possibly of different magnitude and duration) can be applied before any subsequent reversal potential during any particular sequence.

  In some applications, a cathodic pulse having a potential in the range of −0.30 V to −0.55 V with reference to the copper material anode is applied for a period in the range of 5 to 18000 seconds, and after the cathodic pulse, the copper material anode Followed by an anodic pulse in the range of + 0.05V to + 0.60V, whereby the duration of the anodic pulse is shorter than the cathodic pulse, and the open circuit condition is applied during the period between the cathodic pulse and the anodic pulse. It may be advantageous to apply a periodic reversal potential (PPR) condition in which the sequence formed by the cathodic and anodic pulses is repeated 3 to 30 times. Typically, in this case, as the potential is reversed, the open circuit condition becomes 2 during this sequence, ie during the transition from the cathode condition to the anode condition and from the anode condition to the cathode condition. Applied once.

Advantageously, in the process according to the invention, the electrolyte used in the electrorefining process typically ^90g / dm ^{3 ~200g} / dm 3 of _H 2 SO ₄ and ^1g / dm ^{3 ~50g} / dm 3 of Cu, As well as other typical components of such solutions. A very important advantage of the potential controlled process is the possibility of performing electrorefining over a very wide range of copper ion concentrations including less than 40 g / dm ³ . In contrast, industrial current processes require copper (II) ion concentrations of about 40 g / dm ³ or higher. It is important to note that the cathodic potential controlled copper electrorefining process allows the best effective use of natural convection. Natural convection (or slow electrolyte flow) (as an electroactive species), copper sulfate, as pointed out in Russian Journal of Electrochemistry 6 (2004) 723-729 and Russian Journal of Electrochemistry 4 (2008) 459-469 In the presence of additional species different from, the electrolyte component (which is not an electroactive species in the electrorefining process) affects the thickness of the diffusion layer and is therefore advantageous because it results in an increase in the limiting current. Such effects are registered in industrial solutions (complex compositions) and sulfuric acid and copper (II) sulfate, which are only solutions at the ultramicroelectrode, under the conditions where the lowest temperature and potential applied to the cathode are used. Found in steady-state currents. Lukomska, A.A. Plewka and P.M. This idea is supported by the results shown in Los, Journal of Electroanalytical Chemistry 633 (2009) 92-98. This confirms that surface phenomena do not play an important role in constant voltage electrolysis at high potentials and high temperatures. Thus, the presence of other components other than sulfuric acid and copper (II) sulfate is an advantage in the novel, potential controlled process. Another important advantage is that the potential controlled process does not require the addition of organic additives. Such additives are used in current controlled processes to control the structure of the deposited copper. Thus, preferably, the electrolyte is substantially free of such additives including animal glue and / or thiourea. This means that there are no such additives detectable in the electrolyte.

  Typically, the preferred arrangement of electrodes (anode and cathode) is such that the separation of their spaces is 5 cm or less in an industrial cell. In this case, it is also preferable that the electrodes are provided as a substantially planar structure (such as a sheet) arranged in parallel with the predetermined separation distance. In this process, it is also advantageous that the constant voltage copper electrorefining step is typically carried out at a temperature of 18 ° C. to 65 ° C., preferably 18 ° C. to 30 ° C. Thus, there is no need to further heat the electrolyte as in the currently used method. This is a further important advantage since current electrorefining techniques do not allow the use of processes at temperatures below about 50 ° C. As described below, at a temperature as low as 20 ° C., a new constant voltage step can be performed in an industrial electrolyte using a cathode current density comparable to that of the current industrial electrorefining step at 60 ° C. it can. Thus, this new potential controlled electrorefining can be performed using simplified equipment and with great energy savings compared to the current process.

  Using this novel method, it is also convenient to typically perform the constant voltage electrorefining process using a cathode made of stainless steel or copper. Further, the copper material of the anode can be made of a fire-refined, scraped or recycled copper material.

  It is convenient to carry out the constant voltage electrorefining process using an electrolyte that is continuously circulated, stirred or otherwise agitated. Thus, new potential controlled copper electrorefining can be performed in both conventional and ISA facilities currently used in electrorefining. The electrolyte management system can perform one or more of filtering, removing impurities, adding other reagents (such as sulfuric acid), stirring / circulating / stirring and electrolyte temperature control. .

In summary, the cathodic potential controlled copper electrorefining method allows to achieve significantly higher cathode current density (increasing product volume), while high (commercial level) copper purity and microcrystalline structure. The present invention has significant advantages over the prior art methods described above. Typically, the cathodic potential controlled electrorefining process according to the present invention has many advantageous features such as:
In the constant voltage electrorefining process, the electrolyte can have an ionic composition similar to (but not identical to) that currently used in low current processes;
The process can be performed at high current densities up to about 2000 A / m ² at a temperature of 60 ° C. and up to 500 A / m ² at room temperature (about 20 ° C.). In contrast, it will be appreciated that the use of such magnitudes of current density in the constant current electrorefining process results in significant degradation of the copper quality of the cathode;
The purity of the cathode copper obtained in the process of potential controlled electrolysis can be greater than 99.99%;
The “current efficiency” of the constant voltage electrorefining process can be over 97%.

Some examples of the method of electrorefining according to the invention will be described with reference to the following accompanying drawings:
FIG. 1 is a schematic diagram of an apparatus used in connection with an example. FIG. 2 is a flow diagram that provides a general appearance of the method. FIG. 3a shows a potential pulse electrolysis waveform with pulses each having a constant magnitude. FIG. 3b shows a potential pulse electrolysis waveform with a pulse having a constant magnitude other than the initial pulse. FIG. 3c shows the applied potential waveform including a periodic reversal potential. FIG. 3d shows the applied potential waveform including the periodic reversal potential and the intervening period of open circuit conditions.

  A schematic view of an industrial apparatus suitable for carrying out the present invention is specifically described in FIG. Here, a tank 1 is provided, which for simplicity is specifically described as a single container. In practice, it is formed from a number of individual cells made of a polymer material that exhibits good long-term resistance to the electrolyte. The electrolyte has the composition shown in detail in 2 and described in more detail in conjunction with the examples below. A first electrode 3 (shown as a solid line) formed of the resulting copper material is provided and arranged to form an anode in the cell. They take the form of flat sheets and are regularly spaced and suspended vertically in the electrolyte 2. The second electrode 4 (dashed line) is in this case made of either pre-electrorefined copper or stainless steel, but is provided in a form similar to the first electrode and also hangs vertically. ing. The second electrode forms a cathode in each cell and is located at a distance of, for example, 2-3 centimeters from the anode, with an equal space between them. The anode and adjacent cathode can be considered as a “pair” to gain an understanding of the device. A potential controlled power supply 5 is provided to drive the electrorefining process. Each anode is electrically connected to a power source via a supply line 6, and similarly each cathode is also electrically connected by a supply line 7. The electrolyte system 8 is specifically shown. This includes filtering the electrolyte, controlling its composition (by adding and removing impurities / reagents), keeping the electrolyte at a given temperature, and ensuring electrolyte circulation within the cell. Perform many functions. The apparatus is controlled by a controller 9 in communication with an electrolyte system 8 and a power source 5.

  FIG. 2 illustrates a general overview of the process. In step 100, the anode 3 is made of a material that is desired to be refined. In step 200, a clean cathode 4 was obtained (which could be used in a previous electrorefining cycle). In step 300, the anode and cathode are arranged in those cells in the cell 1 and are electrically connected to the power source 5. The electrolyte system 8 is then operated by the controller 9 so that the electrolyte 2 is then introduced into the bath and the electrolyte flow is established within the cell at an appropriate temperature (which can be room temperature). In step 500, the controller 9 operates the power supply 5 to deliver a potential controlled condition. Monitoring of process conditions (including current and potential in each cell) is performed throughout the process by the controller 9. Once the process is stabilized, refining proceeds at step 600. Optionally pulsed electrorefining and / or periodic reversal potentials (described in connection with the examples below) can be applied, but this can include the application of a constant potential. This process continues for a long period (which can be hours or days) until sufficient anode material has been refined. Once this point is reached, power supply is terminated in step 700, the corroded anode is removed (if it does not contain enough material for reuse), and the cathode (containing refined copper) is cleaned. The In step 800, the cleaned cathode is then subjected to mechanical removal of the deposited high purity copper.

  A number of examples are described which can be carried out industrially according to the general apparatus and methods described above. These examples are described with respect to experiments conducted using equipment similar to industrial smelting equipment.

Example 1
A pair of electrodes was provided in an electrochemical cell made of polyvinyl chloride. The cathode is made of stainless steel sheet with a thickness of 0.1 mm and a surface area of 2 cm ² . The anode (reference electrode) is made of a copper sheet having a surface of 0.25 mm thickness and an area of 100 cm ² . This step was performed at room temperature (about 20 ° C.). The vessel was composed of the following composition: 46 g / dm ³ Cu, 180 g / dm ³ H ₂ SO ₄ and 0.1 g / dm ³ Fe, 0.3 g / dm ³ Sb, 0.03 g / dm ³ Bi. , Ni of 5 g / dm ^3, of 10g / dm ³ As, Ag of 0.00015g / dm ^3, Ba of ^{0.001g / dm 3, 0.4g / dm} 3 of Ca, 0.001g / dm ³ of Cd was filled Co of 0.03 g / dm ^3, Mg of 0.02 g / dm ^3, Mn of 0.0004 g / dm ^3, in the electrolyte of Pd and Pb and 0.001 g / dm ³ of 0.007 g / dm ³ . This electrolyte composition resembles, for example, a typical industrial electrorefining electrolyte used in prior art copper electrorefining processes at the KGHM PM copper factory (described above). However, the organic additive was not contained in the electrolyte. In prior art industrial electrolytes, conventional additives such as thiourea and animal glue are subject to hydrolysis, so only a few of their hydrolysis products are present in solution after 2-3 days. According to the description given above, since the presence of a non-electroactive component affects the rate of mass transfer of copper (II) ions to the cathode, and thus the value of the limiting current, the new method can be used in electrolytes containing non-electroactive components. Are preferably tested in Furthermore, since the composite composition electrolyte affects the ionic strength of the electrolyte, and hence the activity coefficient of copper (II) ions, the experimental test is preferably performed in the composite composition electrolyte. Theoretically, the driving force for diffusion is known to be a gradient of activity.

  Each electrode is used to program the duration of a constant voltage electrolysis process from 1 minute to several days and is connected with the help of a special cable to a commercial rectifier that provides current up to 500A flowing from / to the electrode to the electrode It was done. A current that varies with the duration of the electrolysis was measured during the process. This solution was not stirred in this case.

Constant voltage electrolysis parameters used:
Potential of stainless steel cathode with reference to copper anode E = −0.300 V;
Electrolysis time t = 1 hour;
A stationary current density of about 300 A / m ² at the cathode was achieved after a constant potential of −0.300 V was applied to the electrode for about 25 seconds.

  After depositing copper on a stainless steel cathode, the cathode deposit is mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition is studied by the EDS / EDX method. did. It was found that the resulting cathode deposit had a fine crystalline structure without dendrites. Oxygen accounted for about 0.05% mass and was the only impurity present in the resulting cathode copper. Thus, the resulting cathode copper has a purity greater than 99.95%. Comparing the theoretical copper mass to be deposited (using Faraday's law) with the deposited copper mass, it was found that the current efficiency of the process was greater than 97%. In this example, a potential of a magnitude similar to that found in many known industrial (current controlled) prior art refining processes was used.

Example 2
In this second example, the experimental setup and electrolysis conditions are similar to those in Example 1, except that a different cathode potential is used, resulting in a higher current.

Constant voltage electrolysis parameters:
The potential of the stainless steel cathode with reference to the copper anode E = −0.450 V;
Electrolysis time t = 1 hour;
A fixed current density of about 500 A / m ² at the cathode was achieved after a constant potential of −0.450 V was applied to the electrode for about 25 seconds.

  After depositing copper on a stainless steel cathode, the cathode deposit is mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition is studied by the EDS / EDX method. did. Again, as in Example 1, it was found that the resulting cathode deposit had a fine crystalline structure without dendrites. Oxygen accounted for about 0.05% mass and was the only / single impurity present in the resulting cathode copper. Thus, the resulting cathode copper has a purity greater than 99.95%. Comparing the theoretical copper mass to be deposited using Faraday's law with the deposited copper mass, it was found that the current efficiency of the process was greater than 97%. Therefore, despite the use of a process at ambient temperature, the use of a mode cathode voltage under potential control surpasses what has been observed in the prior art industrial process in terms of purity and structure in terms of purity and structure. It was observed that obtained at current density.

Example 3
The experimental settings and electrolysis conditions are the same as in Example 2 except that the process was performed at a high temperature of 60 ° C.

Constant voltage electrolysis parameters:
The potential of the stainless steel cathode with reference to the copper anode E = −0.450 V;
Electrolysis time t = 1 hour;
After applying a constant potential of −0.450 V to the electrode for about 25 seconds, a fixed current density of about 1400 A / m ² at the cathode was achieved.

  After depositing copper on the steel cathode, the cathode deposit was mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition was studied by the EDS / EDX method. did. It was found that the resulting cathode deposit had a fine crystalline structure without dendrites. Oxygen accounted for about 0.05% mass and was the only / single impurity present in the resulting cathode copper. Thus, the resulting cathode copper has a purity greater than 99.95%. Comparing the theoretical copper mass deposited using Faraday's law with the deposited copper mass, it was found that the current efficiency of the process was greater than 97%. Thus, it has been observed that the use of high temperatures with a potential controlled process allows the use of much higher current densities than is observed in the prior art (which results in more rapid copper deposition). Despite the high current density used, a high level of purity was achieved with a beneficial microstructure free of dendrites.

Example 4
Here, the solution was stirred at a frequency of 50 revolutions / minute, but the experimental settings and electrolysis conditions are the same as in Example 3 (including a process temperature of 60 ° C.). A shorter electrolysis period was also used.

Constant voltage electrolysis parameters:
The potential of the stainless steel cathode with reference to the copper anode E = −0.450 V;
Electrolysis time t = 5 minutes After applying a constant potential of −0.450 V to the electrode for about 25 seconds, a fixed current density of about 1600 A / m ² at the cathode was achieved.

  After depositing copper on a stainless steel cathode, the cathode deposit is mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition is studied by the EDS / EDX method. did. It was found that the resulting cathode deposit had a fine crystalline structure without dendrites. Oxygen accounted for about 0.05% mass and was the only / single impurity present in the resulting cathode copper. Thus, the resulting cathode copper has a purity greater than 99.95%. Comparing the theoretical copper mass to be deposited (calculated using Faraday's law) with the deposited copper mass, it was found that the current efficiency of the process was greater than 97%. Thus, it was observed that electrolyte agitation using the observed agitation allows even higher current densities to be achieved under the more potential controlled conditions in Example 3.

  Note that 5 minutes in this case is a time scale sufficient to establish a “fixed” current density and to obtain enough copper to determine the copper mass with high accuracy.

Example 5
In this case, the physical experimental arrangement has been modified to more closely represent an industrial oil refinery plant compared to the above example. Here there are four pairs (actually four cathodes and five anodes) of electrodes arranged in parallel in a 120 liter volume electrochemical cell made of polyvinyl chloride and arranged vertically. The cathode is made of stainless steel sheet, its thickness is 0.3 mm, the cathode surface area is 0.2 m ² , and the anode (reference electrode) is made of 0.25 mm thick copper sheet The surface is 0.22 m ² . The distance between the cathode and each anode is 5 cm. Theoretically, the macro-configuration of the electrolysis cell may significantly affect the limiting current established in natural convection conditions, so that the new potential-controlled electrorefining method is preferably tested in a different configuration. This step was performed at room temperature (about 20 ° C.). Although diluted 2.6 times with sulfuric acid at a concentration of 180 g / dm ³ , the container was filled with an electrolyte of the same composition as shown in Example 1. Thus, the component concentration of each electrolyte shown in Example 1 should be divided by 2.6, except for H ₂ SO ₄ , and for example, the copper concentration is equal to 17.5 g / dm ³ . With the help of a special cable that allows the electrode to be used to program the duration of a constant voltage electrolysis process from 1 minute to several days and to conduct research at currents up to 500A flowing between the rectifier and the electrode Connected. A current that varies with the duration of the electrolysis was measured during the process. This solution was not stirred in this example.

Constant voltage electrolysis parameters:
Potential of stainless steel cathode with reference to copper anode E = −0.350V,
Electrolysis time t = 3 hours After applying a constant potential of −0.350 V to the electrode for about 25 seconds, a fixed current density of about 100 A / m ² at the cathode was achieved.

  After copper is deposited on the stainless steel cathode, the cathode deposit is mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition is determined by EDS / EDX and ASTM copper. Researched by elemental analysis. According to ASTM copper elemental analysis, the copper deposited copper had a purity of> 99.999%. The refined material has a smooth surface free of nodules and dendrites.

  The resulting cathode deposit was found to have a fine crystalline structure. Comparing the theoretical copper mass to be deposited using Faraday's law with the deposited copper mass, it was found that the current efficiency of the process was greater than 96%.

  This shows that the copper concentration can be effectively performed (with high purity, fine crystal structure and high current efficiency) under conditions where the copper concentration is much lower than conventional electrorefining and the temperature is much lower than conventional constant current process Is a very important example.

Example 6
The experimental setup and electrolysis conditions are the same as in Example 5, except that one cathode and two anodes were used. The anode was placed at an equal distance of 25 cm from each side of the cathode.

Constant voltage electrolysis parameters:
Potential of stainless steel cathode with reference to copper anode E = −0.350V,
Electrolysis time t = 2 hours After applying a constant potential of −0.350 V to the electrode for about 25 seconds, a fixed current density of about 100 A / m ² at the cathode was achieved.

  After copper is deposited on the steel cathode, the cathode deposit is mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition is determined by EDS / EDX and XRD methods. Studied. By EDS / EDX and XRD analysis, the copper deposited copper had a purity of> 99.95%. The resulting cathode deposit was found to have a fine crystalline structure. Comparing the theoretical copper mass to be deposited using Faraday's law with the deposited copper mass, it was found that the current efficiency of the process was greater than 83%.

Example 7
The experimental setup and electrolysis conditions are the same as Example 6 except that instead of the stainless steel cathode, a copper cathode made of a 0.25 mm thick copper sheet with a 0.22 m ² surface was used. Again, the anode was used. The anode was placed 5 cm equidistant from each side of the cathode. Further, the composition of the electrolyte is the same as Example 1 except that the copper content is equal to 41 g / dm ³ .

Constant voltage electrolysis parameters:
Copper sheet cathode potential with reference to the copper anode E = −0.550 V;
Electrolysis time t = 4 hours;
After applying a constant potential of -0.550 V to the electrode, an average current density of about 184 A / m ² at the cathode was achieved.

  After copper is deposited on the copper cathode, the cathode deposit is mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition is determined by EDS / EDX and XRD methods. Studied. By EDS / EDX and XRD analysis, the copper deposited copper had a purity of> 99.95%. The refined material was again found to have a smooth surface free of nodules and dendrites. Comparing the theoretical copper mass to be deposited using Faraday's law with the deposited copper mass, it was found that the current efficiency of the process was greater than 99%.

  Website http: // doccopper. tripod. com / copper / ertrend. According to html, periodic current reversal (PCR) is used in at least 11 copper smelters (under galvanic conditions) to increase the production rate of the cathode by increasing the applied current density. PCR is a method in which the forward current is then applied for a length of time that has the next fastest current reversal. The ratio of the forward / reverse period is typically 20/1 to 30/1. W. G. Davenport, M.M. King & M. Schlesinger, entityed Extractive Metallurry of Copper p. According to 282 research papers, the passivation of the copper anode at the cathode current density (when a constant current control step is performed) can also be avoided by periodically reversing the direction of the refining current. The benefit stems from the reverse current depleting the elevated copper concentration in the anode boundary layer. This helps to avoid copper sulfate precipitation which is one of the causes of passivation. The main disadvantage of PCR is higher energy costs. This limited the use of this technique.

  Unexpectedly, the above problem of current PCR has been solved by the present invention. Implementation of the present invention using either potential pulse electrolysis (PPE) or periodic reversal potential (PPR) is described, for example, in Org. Lett. , 13 (2) (2011) pp 280-283, a controlled surface area (coarse) that can be used in certain applications, such as in organic chemical catalysis where a copper tube reactor (CTFR) is used. And / or porosity) and a copper deposit having a structure. “The extremely high surface area is suitable for evaluating some electrochemical reactions, but the copper deposit open structure and porous structure obtained at high current density are used in fuel cells, batteries and chemical sensors, etc. Ideally suited for use as an electrode in electrochemical instruments, for example, in the reaction where copper is reduced to nitrate ions and in a solution where nitric acid is reduced to ammonia in acidic aqueous perchlorate and sulfate media. “It was known to show high activity”, Sensors 7 (2007), 1-15.

Thus, the method can include constant voltage pulse electrolysis (PPE) or periodic reversal potential (PPR) copper deposition or a combination of PPR and PPE. Examples of potential pulse electrolysis (PPE) and periodic reversal potential (PPR) pulses applied to the cathode are shown in FIGS. Here E _c is the cathode potential, t _c is the length of the cathode pulse reversal E _a is an inverted pulse (anode) potentials applied to the cathode, t _a is applied to the cathode This is the length of the potential pulse (anode). An advantageous implementation of the PPE and PPR constant voltage electrolysis process is illustrated in FIGS. 3a) -3d). here:

FIG. 3a) shows a time t _k between 5 seconds and 18000 seconds and a pulse (open circuit) potential interruption between 0.1 seconds and 100 seconds with respect to a copper electrode from −0.3 V to −0. It shows the PPE step having a cathode potential pulse _{E k} in the range of 55V. The number of potential pulses and potential interruptions is 3-30.

FIG. 3b) shows −0.3 V to −0.55 V for a copper electrode with a period t _c of 5 seconds to 18000 seconds and a potential interruption (open circuit) between pulses of 0.1 seconds to 100 seconds. PPE processes with different values in the cathode potential pulse E _c in the range The number of potential pulses and potential interruptions is 3-30.

FIG. 3c) shows a cathodic pulse at a cathodic potential E _c in the range of −0.3 V to −0.55 V with respect to the copper electrode for a period t _c of 5 seconds to 18000 seconds, and then at least 50% shorter than the time t _c. A PPR process with an anodic pulse at anodic potential E _a1 in the range of +0.050 V to +0.6 V with respect to a copper electrode having a period t _a1 was shown. The number of potential pulses and potential interruptions is 3-30.

Cathode potential pulse E _{c in} the range of −0.3 V to −0.55 V with respect to the copper electrode for a period t _c of 5 seconds to 18000 seconds, and then anode and cathode pulses ( In combination with a PPE and PPR process with an anode potential pulse E _a0 in the range of +0.050 V to +0.6 V for a copper electrode with a period t _a0 ≦ t _c showed that. The number of potential pulses and potential interruptions is 3-30.

  Specific examples of copper electrorefining by the PPE and PPR processes are described in Examples 8-10 below.

Example 8
In this example, a pair of electrodes was provided in an electrochemical tank made of polyvinyl chloride. The cathode was made of a stainless steel sheet having a thickness of 0.3 mm. The anode (reference electrode) was made of a 0.25 mm thick copper sheet with a surface of 0.22 m ² . This step was performed at room temperature (about 20 ° C.). The container was filled with an electrolyte of the same composition as shown in Example 1.

  Each electrode was connected with the help of a special cable to a commercial rectifier that could be used to program the period of a periodic reversal potential (PPR) electrolysis process. The applied potential period can be controlled from 1 ms to several days using currents up to 500 A flowing between the rectifier and the electrodes. A current that varies with the duration of the electrolysis was measured during the process. This solution was not stirred in this example.

Parameters of PPR electrolysis:
Cathode pulse 1
E = -300mV
t = 5 minutes j = -360 A / m ²
Cathode pulse 2:
E = -350mV
t = 5 minutes j = −430 A / m ²
Anode pulse:
E = + 400mV
t = 30 seconds I = + 500 A / m ²
The above sequence of pulses was repeated three times.

  After depositing copper on the steel cathode, the cathode deposit was mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition was determined using the EDS / EDX method and X It was studied with the line diffraction (XRD) technique. It was found that the resulting cathode deposit had a fine crystalline structure without dendrites. During the anodic pulse, the electrodeposited copper on the cathode undergoes anodic dissolution (corrosion) at the particle limit, so the copper sheet surface roughness is much higher than in the case of constant voltage electrolysis shown in Examples 1-7. . Oxygen accounted for about 0.05% mass and was the only / single impurity present in the resulting cathode copper. Thus, the resulting cathode copper has a purity greater than 99.95%. Comparing the theoretical copper mass to be deposited using Faraday's law with the deposited copper mass, it was found that the current efficiency of the process was greater than 98%.

Example 9
Experimental settings and electrolysis conditions are the same as in Example 8.

Parameters of PPR electrolysis:
Cathode pulse 1:
E = -300mV
t = 5 minutes j = −490 A / m ²
Cathode pulse 2:
E = -350mV
t = 5 minutes j = −520 A / m ²
Anode pulse:
E = + 600mV
t = 30 seconds I = + 550 A / m ²
The above sequence of pulses was repeated three times.

  After depositing copper on the steel cathode, the cathode deposit was mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition was determined using the EDS / EDX method and X It was studied with the line diffraction (XRD) technique. The resulting cathode deposit was found to have a crude crystal structure without dendrites. During the anodic pulse, the electrodeposited copper undergoes pit corrosion and thus the copper sheet surface roughness / porosity is much higher than for the constant voltage electrolysis shown in Examples 1-7. Oxygen accounted for about 0.05% mass and was the only / single impurity present in the resulting cathode copper. Thus, the resulting cathode copper has a purity greater than 99.95%.

  Comparing the theoretical copper mass to be deposited using Faraday's law with the deposited copper mass, it was found that the current efficiency of the process was greater than 97%.

Example 10
This example uses a PPE process that is the application of a cathodic pulse incorporating short circuit zero potential interruption and no anodic pulse. Experimental settings and electrolysis conditions are the same as in Example 8.

Parameters of PPE electrolysis:
Cathode pulse 1:
E = -300mV
t = 5 minutes j = −460 A / m ²
Potential interruption:
E = 0mV
t = 1 second I = 0 A / m ²
Cathode pulse 2:
E = -450mV
t = 5 minutes j = −560 A / m ²
The above sequence of pulses was repeated three times.

  After depositing copper on the steel cathode, the cathode deposit was mechanically removed from the cathode, washed with water, air dried, and the resulting copper composition was determined using the EDS / EDX method and X It was studied with the line diffraction (XRD) technique. It was found that the resulting cathode deposit had a columnar crystal structure without dendrites, and thus the copper sheet surface roughness was greater than for the constant voltage electrolysis shown in Examples 1-7. Oxygen accounted for about 0.05% mass and was the only / single impurity present in the resulting cathode copper. Thus, the resulting cathode copper has a purity greater than 99.95%. Comparing the theoretical copper mass to be deposited using Faraday's law with the deposited copper mass, it was found that the current efficiency of the process was greater than 98%.

Industrial Implementation It will be understood that each of the above examples represents an industrial application of the present invention. Of course, in carrying out the present invention on an industrial scale, it is preferable to optimize the process by adjusting parameters relating to the process for the specific industrial process of interest. This includes optimization of parameters such as size, shape, and relative position of anode and cathode, control of electrolyte treatment including content and flow, process temperature and of course potential control conditions Can do. Thus, the guidance provided by the above example can be used to achieve the most efficient process for the desired combination of copper deposition rate and quality.

Claims (21)

  Arranging at least one anode of the copper material to be refined in contact with the electrolyte solution; Arranging at least one cathode in contact with the electrolyte solution; and electrically connecting the anode and the cathode to a power source Operating the power supply under a controlled condition potential to be between at least a portion of the process and application of the condition, and the potential at the cathode is -0 to the copper material at the anode. Industrial copper electrorefining method comprising: 30V to -0.55V, thereby producing a deposit of electrorefined copper at the cathode.   The method of claim 1, wherein the potential controlled condition comprises application of a combined form of potential.   3. The method of claim 2, wherein one or more of the magnitude and polarity of the potential is adjusted during the conditions.   The method of claim 3, wherein the potential is adjusted as a square wave form having the magnitude of the potential at the cathode from −0.30 V to −0.55 V.   Many cathodic pulses in the range of 3 to 300 are applied, each having a substantially constant potential in the range of −0.30 V to −0.55 V with reference to the copper material at the anode, and each Constant voltage pulse electrolysis (PPE) conditions having a period between 5 and 18000 seconds, the pulses being separated by an open circuit break in time, each having a time in the range of 0.1 to 100 seconds The method according to claim 1, wherein the condition comprises.   A cathodic pulse having a potential in the range of −0.30 V to −0.55 V with reference to the copper material anode is applied for a period in the range of 5 to 18000 seconds, with reference to the copper material anode after the cathodic pulse. An anodic pulse in the range of + 0.05V to + 0.60V follows, whereby the duration of the anodic pulse is at least 50% shorter than the cathodic pulse, and the sequence formed by the cathodic and anodic pulses is 3-30. 4. The method of any one of claims 1-3, wherein the condition comprises a periodic reversal potential (PPR) condition that is repeated times.   A cathodic pulse having a potential in the range of −0.30 V to −0.55 V with reference to the copper material anode is applied for a period in the range of 5 to 18000 seconds, with reference to the copper material anode after the cathodic pulse. Followed by an anodic pulse in the range of +0.05 V to +0.60 V, whereby the duration of the anodic pulse is shorter than the cathodic pulse, and an open circuit condition is applied during the period between the cathodic pulse and the anodic pulse; 4. The method according to any one of claims 1 to 3, wherein the condition includes a periodic reversal potential (PPR) condition, wherein a sequence formed by the cathodic and anodic pulses is repeated 3 to 30 times. .   The method of claim 7, wherein the open circuit condition is applied twice during the sequence as the potential is reversed.   9. The method according to any one of claims 1 to 8, wherein the at least one anode and at least one cathode are arranged in at least a pair, and the distance between the pair of cathodes and the anode is 5 cm or less. .   The method according to claim 1, wherein the current efficiency of the method is 95% or more. Electrolyte containing Cu of 90g ^/ dm ³ ~200g ^/ dm 3 of _H 2 SO ₄ and ^1g / dm ^{3 ~50g} / dm 3 are used, the method according to any one of claims 1 to 10.   The method according to any one of claims 1 to 11, wherein the method is carried out at a temperature of 18C to 65C.   The method according to claim 12, wherein the method is carried out at a temperature of 18C to 30C.   14. The method of any one of claims 1-13, further comprising first forming the at least one anode from a dry smelted, scrap or recycled copper material.   15. A method according to any one of the preceding claims, wherein the method is carried out using a cathode made of stainless steel or copper.   16. The method of any one of claims 1-15, further comprising moving the electrolyte relative to the anode and the cathode during the electrorefining.   17. A method according to any one of claims 1 to 16, wherein the electrolyte is substantially free of any organic additives.   18. A method according to any one of claims 1 to 17, wherein the refined copper has a purity greater than 99.95%. A container for holding an industrial electrolyte;
At least one first electrode made of a copper material placed and refined to be used in contact with the industrial electrolyte in the vessel;
At least one second electrode placed to be used in contact with the industrial electrolyte in the container;
When used for each of the at least one first electrode and at least one second electrode, during at least part of the application of the condition, the potential at the at least one second electrode is at least the at least one Potential control to be -0.30 V to -0.55 V with respect to the copper material at one first electrode, thereby causing electrorefined copper deposition at the at least one second electrode A conditionally and electrically connected power source;
Including industrial copper electric refining system.   The system of claim 19, further comprising an electrolyte management system arranged to control movement of the electrolyte in the vessel and to adjust the composition of the electrolyte during an electrorefining process.   21. An apparatus according to claim 19 or claim 20, further adapted for use in performing the method of any one of claims 1-18.

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