Electrochemical method for deposition / electrorefining of copper

Abstract

The invention relates to a method for electrorefining of copper carried out in a two-electrode system from an aqueous solution of CuSO4 and H2SO4 containing Fe, Ni and As ions, in industrial practice preferably at concentrations of 1 g / dm³, and Co, Cd, Sb, Pb and Bi ions, in industrial practice preferably at concentrations of 0.1 g / dm3, using the potentiodynamic method with a linear rate of change of an electrolytic bath potential, characterised in that the linear rate of change of the electrolytic bath potential is from 0.1 V / s to 0.5 V / s, while the bath potential is from 0.2 to 0.4 V.

Description

[0001] Electrochemical method for deposition / electrorefining of copper

[0002] The invention relates to an electrochemical method for deposition / electrorefining copper from industrial electrolytes.

[0003] Copper is an extremely important industrial raw material due to a number of beneficial physical and chemical properties that make it attractive for practical applications. These properties include high electrical conductivity, plasticity and very good thermal conductivity.

[0004] Electrorefining is a unit process that involves the electrochemical dissolution of copper from contaminated copper anodes in an electrolyte containing copper(II) sulphate(VI) and sulphuric acid(VI) (CuSO4 and H2 SO4) and the selective electroplating of pure copper from this electrolyte, eliminating anode impurities. This produces copper that is virtually free of impurities, while separating valuable metals such as gold and silver from the copper, allowing them to be recovered as by-products. Copper anodes with a typical purity of 98.5% to 99.5% Cu are electrorefined to obtain cathodes with a purity of over 99.997% Cu. Electrorefmed copper, after melting and casting, contains less than 20 ppm of impurities and oxygen, which is controlled at a level of 0.018% to 0.025%. An electrical potential is applied between the copper anode and the metal cathode in an electrolyte containing CuSC and H2SO4, an electrical potential is applied, resulting in the electrochemical dissolution of copper from the anode into the electrolyte, forming:

[0005] Cu° -► Cu2++ 2e~ E° = -0.34 V,

[0006] As a result of the reaction, electrons are conducted towards the cathode and Cu2+cations migrate to the cathode by diffusion. Electrons and copper ions combine on the cathode surface to form metallic copper, free of anode impurities.

[0007] Cu2++ 2e~ -► Cu° E° = +0.34 V,

[0008] In general, the electrowinning process is the sum of the reactions described above.

[0009] The applied electrical voltage causes the oxidation of metallic copper at the anode and the reduction of Cu2+to metallic copper at the cathode. This process works effectively because copper is more easily oxidised and reduced than water. Metallic impurities with a lower reduction potential than copper, which are less noble, easily dissolve at the anode. More noble metals with a higher reduction potential do not dissolve at the anode but accumulate at the bottom of the cell as anode slime. Anode slimes can be captured and processed to recover valuable metals.

[0010] Cell voltage and current density are two key parameters in the copper electrowinning process. The total voltage is determined by the equilibrium cell voltage, the anode and cathode overpotentials, and the ohmic potential drop of the electrolyte, equipment and power supply. It is generally accepted that copper production increases with increasing current density, although this comes at the expense of current efficiency.

[0011] Electrochemical processes, such as electrolytic copper deposition and electrorefining of copper obtained in pyrometallurgical processes, are effective methods of increasing the purity of the metal obtained. Virtually all copper produced in pyrometallurgical processes undergoes electrolytic refining. In addition, hydrometal lurgi cal methods based on electrochemical deposition are used not only in refining, but also in the direct extraction of copper from ores.

[0012] Electrorefining technology has been known since the 19th century, and the first patents for copper electrorefining appeared between 1865 and 1870. Today, this method is widely used in industry. Commonly used methods of copper electrowinning and electrorefining are based on direct cunent electrolysis carried out under galvanostatic conditions, i.e. with strict control of the current intensity in the system. In these processes, the cathode current density is maintained at a level of 2.4 A / dm2to 4 A / dm2, with a bath voltage of 0.25 V to 0.40 V, the electrochemical efficiency of copper recovery is 93% to 98%, and energy consumption is approximately 290 kWh / t to 435 kWh / t. The copper electrorefining process is carried out at a temperature of approximately 60°C with a copper ion concentration in the electrolyte of 45 g / 1 to 50 g / 1 and a sulphuric acid concentration of 160 g / 1 to 200 g / 1.

[0013] A modification of standard galvanostatic electrolysis is a method of electrolytic extraction of copper with increased hardness and electrical conductivity, known from US20060021878 patent description. The described electrolytic process is carried out in a pulsed mode with currents ranging from 4 to 10 A / dm2and pulse durations from 10 ms to 50 ms, interrupted by intervals (in open circuit conditions) lasting from 1 s to 3 s.

[0014] A separate technological category is represented by electro-deposition methods based on electrolysis carried out under conditions of constant, precisely controlled voltage, also known as controlled potential conditions. These methods, using stable electrode potentials, enable increased selectivity and energy efficiency of the process. The process of electrolytic copper deposition under constant cathode potential conditions, maintained in the range of -1.0 V to -1.5 V relative to an anode made of acid-resistant steel, is described in PL396693 patent.

[0015] Patent descriptions US20120093680A1 and PL212865B1 present a method for the electrochemical deposition of copper in the form of powders and nanopowders from waste solutions containing copper ions. In this approach, electrodeposition is earned out under controlled potential conditions, using one or more potential pulses of a specified voltage and duration. In this process, copper deposition occurs on a cathode made of steel, gold or platinum, relative to a soluble copper anode. According to patent description PL238274 and patent application P-427456, the electrochemical deposition method has been further developed, in particular for the deposition of other metals. It has been demonstrated that this method has been successfully used to purify phosphoric acid from heavy metals and to obtain zinc powders and nanopowders. According to the publication by S. Luchcinska, J. Lach, K. Wrobel, A. Lukomska and P. Los entitled "The recovery of metals as high value powders and nanopowders from industrial wastewaters using potential-controlled electrolysis", published in the International Journal of Environmental Science and Technology (2022), DOI: 0.1007 / sl3762-022-04401-7, potential-controlled electrolysis has been successfully used to recover cobalt and chromium powders from industrial wastewaters. Additionally, according to a publication by P. Los, A. Labuza, A. Sobianowska-Turek, A. Fornalczyk, M. Zygmunt, M. Janosz entitled "Potentiodynamic copper electrowinning. Laboratory and pilot scale studies" published in the journal Przemysl Chemiczny (2024), DOI: 10.15199 / 62.2024.1.12, the authors demonstrated that it is possible to potency-dynamically de-copper very special solutions obtained as a result of acid reduction leaching of lithium-ion battery masses to a level below 20 ppm of copper. The cathode copper obtained in the process was in the form of a solid cathode, foil or powders (or nanopowders).

[0016] The patent description WO2013075889A1 disclosed a method for electrorefining copper under controlled cathode potential conditions, maintained in the range of -0.30 to -0.55V relative to a copper anode, which simultaneously acts as a source of refined metal. According to the description, this method also includes potentiostatic positive electrolysis and periodic reversal of the electrode potential to produce a copper coating with a controlled structure, for example in terms of roughness or porosity.

[0017] The invention relates to a method of copper electrorefining carried out in a two-electrode system from an aqueous solution of CuSCU and H2SO4 containing Fe, Ni, As ions, in industrial practice preferably at concentrations of 1 g / dm3, and Co, Cd, Sb, Pb and Bi ions, in industrial practice preferably at concentrations of 0.1 g / dm3, using the potentiodynamic method with a linear rate of change of a electrolytic bath potential, characterised in that the linear rate of change of the electrolytic bath potential is from 0.1 V / s to 0.5 V / s, while the bath potential is from 0.2 to 0.4 V.

[0018] Preferably, anode is made of copper with a purity of 98%, and cathode is made of steel or copper.

[0019] Preferably, the concentration of copper ions in the electrolyte is above 40 g / dm3and that of sulphuric acid is above 150 g / dm3.

[0020] Preferably, the process is carried out without stirring.

[0021] Preferably, the process is carried out at room temperature or at elevated temperatures up to 50°C.

[0022] Preferably, the cathode current density at room temperature is between 1.92 and 2.28 A / dm2and at 50°C between 3.83 A / dm3and 5.51 A / dm2.

[0023] The subject of this invention is a method for the electrochemical deposition of high-purity copper in metallic form by cathodic reduction from solution. In the described method, the electrochemical deposition of copper on the cathode is carried out in a two-electrode system, in the presence of a soluble anode (counter electrode) and acidic electrolytes based on copper(II) sulphate (VI). This process takes place under potentiodynamic conditions, where the electrode potential is cyclically modified at a fixed rate. The electrochemical conditions used lead to the maintenance of the diffusion layer under conditions of constant disturbance, which results in accelerated mass transport to the electrode area. As a result, the described solution enables a significant reduction in energy consumption throughout the electrochemical process by eliminating the need for stirring and maintaining an elevated electrolyte temperature, as well as by achieving conditions of high electrochemical efficiency (Faraday efficiency). Under the experimental conditions described in the Examples below, both at room temperature and at 50°C, energy consumption ranges between 256 kWh / t and 260 kWh / t. The use of a two- electrode system, compared to a three-electrode system, offers high potential in terms of scaling and implementing the technology for industrial applications.

[0024] In the case of electrochemical copper extraction or electrorefining, high-power industrial rectifiers allow the right electrical conditions to be maintained throughout the process, which is crucial for obtaining high-quality cathode copper with the desired purity and electrochemical efficiency.

[0025] High-power industrial rectifiers are key devices in large-scale electrochemical processes such as the electrochemical deposition or electrorefining of metals, including copper. In the context of the previous content, industrial rectifiers play an important role in ensuring the appropriate voltage and current flow in electrolysis. Advances in power electronics enable the creation of systems that provide smooth conversion and control of electrical energy without connection losses, and microprocessor techniques allow for the generation of a precise control signal.

[0026] The state of knowledge on industrial rectifiers for electrorefining in the context of the present invention includes their technical ability to maintain a linear potential change within a narrow range while simultaneously flowing a high electrolysis current, typical of commercial operating conditions. Implementing such a function requires solving several key technical problems. One of the main challenges is to ensure process stability at varying potentials in order to avoid undesirable fluctuations in current or electrode potential. Currently existing rectifiers are capable of providing adequate voltage and current stability under high load conditions or when conducting the process in accordance with the assumed potential changes. In order to meet these challenges, the technical solutions currently in use include advanced control algorithms, the use of high-quality power electronic components, and continuous improvement of the design and operating parameters of industrial rectifiers. In the context of controlling industrial rectifiers for electrorefining, it is important to use advanced algorithms that enable precise control of the electrolysis process. The first key element is to ensure voltage and current stability under conditions of changing electrode potential. For this purpose, advanced control systems are used, which monitor electrical parameters and dynamically adjust the operation of the rectifier in real time in accordance with the process assumptions.

[0027] The control algorithms must also take into account the specific requirements of the electrolysis process, such as maintaining a constant rate of potential change within a specified range, preventing current oscillations and minimising power losses. For this purpose, advanced control techniques or advanced adaptive algorithms are used, which allow for optimal control of voltage and current depending on changing operating conditions.

[0028] In addition, it is important to monitor and diagnose the rectifier's operation in real time in order to detect any faults or malfunctions. For this purpose, supervision and control systems are used to analyse the rectifier's operating parameters and record not only the entire process, but also any anomalies or malfunctions, allowing for a quick response and elimination of problems.

[0029] It is also worth noting that the development of control technology for industrial rectifiers for electrorefining also includes work on process automation, integration with monitoring and control systems, and the use of loT (Internet of Things) and artificial intelligence technologies for even more efficient and reliable management of the electrolysis process.

[0030] In the electrochemical process described above, it is essential to maintain a controlled and variable voltage between the cathode and anode. Advances in power electronics and microprocessor systems allow the specified parameters to be maintained, as modem industrial rectifiers ensure a stable supply of electrical voltage, which, with the appropriate control systems, enables precise control of the process in accordance with the requirements of this invention. In addition, rectifiers must be sufficiently efficient to provide the power needed to carry out electrolysis on an industrial scale, and appropriately selected algorithms in control systems allow for complex process conditions and the production of high-purity, high-quality products.

[0031] It is worth noting the challenges associated with digital signal processing, especially in the context of recording and mapping data from the designed process. The recorded characteristics of the rectifier for three different values of voltage rise are shown in Fig. 1, where: a) shows a rise of 0.1 V / s, b) shows a rise of 0.3 V / s, and c) shows a rise of 0.5 V / s.

[0032] The graphs presented illustrate the negative phenomenon of aliasing, which occurs in the field of digital signal processing and can lead to incorrect signal representation. Aliasing occurs when the signal frequency is too high in relation to the sampling frequency. When sampling an analogue signal at too low a frequency, false frequencies may appear which are a representation of the actual signal frequencies but are outside the Nyquist range, resulting in incorrect signal reconstruction after digital processing.

[0033] The recorded signals were obtained for an idealised reception system with only resistive load, and the resistance values were selected empirically for the given voltage. The test was carried out using proprietary software to control the rectifier and with the assumption of signal recording at a frequency of 2.5Hz.

[0034] These issues were taken into account when designing the rectifier, its controller and the control algorithms for the reported invention. The electrochemical method of separating / electro-refining copper from acidic solutions based on copper(VI) sulphate, which allows high-purity cathode copper to be obtained, according to the present invention, is characterised by conducting the process in a two-electrode system (anode-cathode) under potentiodynamic conditions. This means that the voltage is controlled and cyclically changed over time. In this method, a stable metal electrode is used as the cathode, while the anode is a soluble electrode made of industrial copper, for example, smelting copper. Additionally, the electrochemical process takes place without mixing the electrolyte.

[0035] In the method according to the described invention, the electrochemical process is carried out under controlled, time-varying voltage conditions, where the cathode potential is cyclically modified in the range from -0.2 V to -0.4 V at a fixed rate (polarisation) in the range from 0.1 V / s to 0.5 V / s.

[0036] In the method described in this invention, the electrochemical process is carried out without the need to stir the electrolyte, occurring at room temperature or under elevated temperature conditions, particularly favourable at a temperature of 50°C.

[0037] As mentioned earlier, in the method according to the present invention, the electrolyser consists of a two-electrode system comprising an insoluble (stable under the operating conditions of the system) cathode and a soluble anode. The ratio of the cathode surface area to the anode surface area is 1 : 1. Preferably, acid-resistant steel is used as the cathode material, while metallurgical copper (with a purity of approximately 98%) or anode copper (with a purity of approximately 99.0% - 99.5%) can be used as the anode material.

[0038] According to the invention, it has been found that in the process of potentiodynamic copper electrowinning, the cathode current densities achieved can be up to 30% higher than the highest current densities (approximately 4 A / dm2) used in the industrial process of galvanostatic copper electrowinning.

[0039] According to the invention, the electrochemical process can be carried out until a specific mass of cathode copper is obtained or the anode is completely dissolved. In addition, a detailed description of the invention is provided in the examples of implementation, which present a favourable variant of the invention, without limiting the scope of the protection sought. Example 1. Electrochemical deposition / electrorefining of copper

[0040] Electrochemical deposition / electrorefining of copper was carried out from a CuSCL solution (with a Cu ion content of 40 g / dm3) in a II2SO4 solution (150 g / dm3) with the addition of Fe, Ni and As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0.1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from -0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.1 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at room temperature, without stirring the electrolyte, for 30 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of pure copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to the anode surface area was 1 : 1. As a result of the electrolysis, during which the average cathode current density was 2.28 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. The cathode deposit obtained in the process was examined using the SEM / EDS method. Analysis of the results obtained indicates that the process results in the electrowinning of anode copper, as the process produces metallic cathode copper with a purity of 99.2% with an electrochemical efficiency of 98.0% and energy consumption of 258 kWh / t of copper extracted.

[0041] Example 2. Electrochemical deposition / electrorefining of copper

[0042] Electrochemical deposition / electrorefining of copper was carried out from a Q1SO4 solution (with a Cu ion content of 40 g / dm3) in a H2SO44 solution (150 g / dm3) with the addition of Fe, Ni and As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0.1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from -0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.1 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at room temperature, without stirring the electrolyte, for 30 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of industrial anode copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to the anode surface area was 1 : 1. As a result of the electrolysis, during which the average cathode current density was 1.94 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. The cathode deposit obtained in the process was examined using the SEM / EDS method. Analysis of the results indicates that the process results in the electrowinning of anode copper, as it produces metallic cathode copper with a purity of 99.4% with an electrochemical efficiency of 95.9% and energy consumption of 264 kWh / t of copper extracted.

[0043] Example 3. Electrochemical deposition / electro-refming of copper

[0044] Electrochemical deposition / electro-refming of copper was carried out from a CuSO-i solution (with a Cu ion content of 40 g'dm3) in a H2SO4 solution (150 g / dm3) with the addition of Fe, Ni and As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0.1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper el ectrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the range of potentials from -0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.1 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at room temperature, without stirring the electrolyte, for 60 minutes. A flat steel electrode with a working area of approx. 4.0 cm2was used as the cathode, while a flat electrode made of industrial anode copper with a working area of approx. 4.0 cm2was used as the anode. The ratio of the cathode to anode area was 1 : 1. As a result of the electrolysis, during which the average cathode current density was 1.92 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. The cathode deposit obtained in the process was examined using the SEM / EDS method. Analysis of the results indicates that the process results in the electrowinning of anode copper, as it produces metallic cathode copper with a purity of 99.3% with an electrochemical efficiency of 98.9% and energy consumption of 256 kWh / t of copper extracted.

[0045] Example 4. Electrochemical deposition / electrorefining of copper

[0046] Electrochemical deposition / electrorefining of copper was carried out from a CuSCh solution (with a Cu ion content of 40 g / dm3) in a H2SO4 solution (150 g / dm3) with the addition of Fe, Ni and As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0.1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from - 0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.1 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at a temperature of 50°C, without stirring the electrolyte, for 30 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of pure copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to the anode surface area was 1 : 1. As a result of the electrolysis, during which the average cathode current density was 4.37 A / dm2, a layer of metallic deposit was obtained on the cathode surface. The cathode deposit obtained in the process was examined using the SEMZEDS method. Analysis of the results indicates that the process results in the electrowinning of anode copper, as the process produces metallic cathode copper with a purity of 99.4% and an electrochemical efficiency of 97.5%.

[0047] Example 5. Electrochemical deposition / electrorefining of copper

[0048] Electrochemical deposition / electrorefining of copper was carried out from a Q1SO4 solution (with a Cu ion content of 40 g / dm3) in a H2SO4 solution (150 g / dm3) with the addition of Fe, Ni, As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi at a level of 0.1 g / dm3) solution with the addition of Fe, Ni, As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi at a level of 0.1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from -0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.1 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at a temperature of 50°C, without stirring the electrolyte, for 30 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of industrial anode copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to anode surface area was 1: 1. As a result of the electrolysis, during which the average cathode current density was 5.51 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. The cathode deposit obtained in the process was examined using the SEMZEDS method. Analysis of the results indicates that the process results in the electrowinning of anode copper, as it produces metallic cathode copper with a purity of 99.2% with an electrochemical efficiency of 98.8% and energy consumption of 256 kWh / t of copper extracted.

[0049] Example 6. Electrochemical deposition / electrorefining of copper

[0050] Electrochemical deposition / electrorefining of copper was carried out from a CuSCh solution (with a Cu ion content of 40 g / dm3) in a H2SO4 solution (150 g / dm3) with the addition of Fe, Ni and As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0. 1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from - 0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.1 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at a temperature of 50°C, without stirring the electrolyte, for 60 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of industrial anode copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to the anode surface area was 1 : 1. As a result of the electrolysis carried out, during which the average cathode current density was 4.35 A / dm2and the average cathode current density was 4.20 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. The cathode deposit obtained in the process was examined using the SEM / EDS method. Analysis of the results indicates that the process results in the electrowinning of anode copper, as the process produces metallic cathode copper with a purity of 99.5% with an electrochemical efficiency of 99.0% and an energy consumption of 256 kWh / t of copper deposited.

[0051] Example 7. Electrochemical deposition / electrorefining of copper

[0052] Electrochemical deposition / electrorefining of copper was carried out from a CuSC solution (with a Cu ion content of 40 g'dm3) in a H2SO4 solution (150 g / dmJ) with the addition of Fe, Ni and As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0.1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from - 0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.1 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at a temperature of 50°C, without stirring the electrolyte, for 300 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of industrial anode copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to anode surface area was 1 : 1. As a result of the electrolysis, during which the average cathode current density was 4.35 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. After the process, the electrode materials (anode and cathode deposit) were examined using SEM / EDS and XRF methods. Analysis of the results indicates that the process results in the electrorefining of anode copper, as the process using an anode with a purity of 97.66% yields metallic cathode copper with a purity of 99.59% with an electrochemical efficiency of 98.5% and energy consumption of 257 kWh / t of copper separated.

[0053] Example 8. Electrochemical deposition / electrorefining of copper

[0054] Electrochemical deposition / electrorefining of copper was carried out from a CuSCh solution (with a Cu ion content of 40 g / dm3) in a H2SO4 solution (150 g / dm3) with the addition of Fe, Ni and As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0. 1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from - 0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.3 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at a temperature of 50°C, without stirring the electrolyte, for 30 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of industrial anode copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to the anode surface area was 1 : 1. As a result of the electrolysis, during which the average cathode current density was 4.39 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. The cathode deposit obtained in the process was examined using the SEM / EDS method. Analysis of the results indicates that the process results in the electrowinning of anode copper, as it produces metallic cathode copper with a purity of 99.2% with an electrochemical efficiency of 98.2% and energy consumption of 258 kWh / t of copper extracted. Example 9. Electrochemical deposition / electrorefining of copper

[0055] Electrochemical deposition / electrorefining of copper was carried out from a CuSCri solution (with a Cu ion content of 40 g / dm3) in a H2SO4 solution (150 g / dm3) with the addition of Fe, Ni, As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi at a level of 0.1 g / dm3) solution with the addition of Fe, Ni, As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0.1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from -0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.5 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at a temperature of 50°C, without stirring the electrolyte, for 30 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of industrial anode copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to anode surface area was 1 : 1. As a result of the electrolysis, during which the average cathode current density was 4.35 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. The cathode deposit obtained in the process was examined using the SEM / EDS method. Analysis of the results indicates that the process results in the electro winning of anode copper, as it produces metallic cathode copper with a purity of 99.5% with an electrochemical efficiency of 94.1% and energy consumption of 269 kWh / t of copper extracted.

[0056] Example 10. Electrochemical deposition / electrorefining of copper

[0057] Electrochemical deposition / electrorefining of copper was carried out from a CuSCU solution (with a Cu ion content of 40 g / dm3) in a H2SO4 solution (150 g / dmJ) with the addition of Fe, Ni and As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0.1 g / dm3. The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from - 0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.3 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at a temperature of 50°C, without stirring the electrolyte, for 300 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of industrial anode copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to anode surface area was 1 : 1. As a result of the electrolysis, during which the average cathode current density was 3.83 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. After the process, the electrode materials (anode and cathode deposit) were examined using SEM / EDS and XRF methods. Analysis of the results indicates that the process results in the electrowinning of anode copper, as the process using an anode with a purity of 97.66% yields metallic cathode copper with a purity of 99.50% with an electrochemical efficiency of 98.8% and energy consumption of 256 kWh / t of copper extracted.

[0058] Example 11. Electrochemical deposition / electrorefining of copper

[0059] Electrochemical deposition / electrorefining of copper was carried out from a CuSC solution (with a Cu ion content of 40 g / dm3) in a H2SO4 solution (150 g / dm3) with the addition of Fe, Ni and As ions at a level of 1 g / dm3and Co, Cd, Sb, Pb and Bi ions at a level of 0.1 g / dm< The qualitative and quantitative composition of the solution used was selected to be similar to the composition of the solution used in some industrial copper electrowinning processes. The electrochemical process was carried out in a two-electrode system under potentiodynamic conditions, using a controlled, cyclically variable voltage method, in the potential range from - 0.2 V to -0.4 V (relative to the cathode) with a polarisation rate of 0.5 V / s. The process was carried out using a potentiostat (VoltaLab PGZ 301). Electrolysis was carried out at a temperature of 50°C, without stirring the electrolyte, for 300 minutes. A flat steel electrode with a working surface of approx. 4.0 cm2was used as the cathode, while a flat electrode made of industrial anode copper with a working surface of approx. 4.0 cm2was used as the anode. The ratio of the cathode to anode surface area was 1 : 1. As a result of the electrolysis, during which the average cathode current density was 5.20 A / dm2, a layer of metallic deposit in solid form was obtained on the cathode surface. After the process, the electrode materials (anode and cathode deposit) were examined using SEM / EDS and XRF methods. Analysis of the results indicates that the process results in the electrowinning of anode copper, as the process using an anode with a purity of 97.66% yields metallic cathode copper with a purity of 99.60% with an electrochemical efficiency of 99.5% and energy consumption of 254 kWh / t of copper extracted.

Claims

Patent claims1 . A method for electrorefining of copper carried out in a two-electrode system from an aqueous solution of CuSC and H2SO4 containing Fe, Ni and As ions, in industrial practice preferably at concentrations of 1 g / dm3; and Co, Cd, Sb, Pb and Bi ions, in industrial practice preferably at concentrations of 0.1 g / dm3, using a potentiodynamic method with a linear rate of change of an electrolytic bath potential, characterised in that the linear rate of change of the electrolytic bath potential is from 0.1 V / s to 0.5 V / s, while the bath potential is from 0.2 to 0.4 V.

2. The method according to claim 1, characterised in that anode is made of copper with a purity of 98% and cathode is made of steel or copper.

3. The method according to claim 1, characterised in that the concentration of copper ions in the electrolyte is above 40 g / dm3and a concentration of sulphuric acid is above 150 g m3.

4. The method according to claim 1, characterised in that the process is carried out without stirring.

5. The method according to claim 1, characterised in that the process is carried out at room temperature or at elevated temperatures up to 50°C.

6. The method according to claim 1, characterised in that a cathodic current density at room temperature is between 1.92 and 2.28 A / dnfand at 50°C between 3.83 A / dm and 5.51 A / dm2

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