EA035935B1 - Method of recovering gold from a gold-bearing concentrated copper chloride solution - Google Patents

Abstract

The invention relates to a method of recovering gold from a gold-bearing concentrated copper chloride solution comprising: a) an electrodeposition step, wherein an external potential or reducing current is applied to an electrode contained in the gold-bearing concentrated copper chloride solution thereby depositing copper and optionally gold on the electrode, b) a redox replacement step, wherein the in step a) applied external potential or reducing current is cut-off or reduced thereby allowing copper deposited on the electrode to be replaced spontaneously by gold contained in the solution thereby obtaining an electrode which contains gold.

Description

Technology area

The present invention relates to a method for recovering gold from a gold-bearing solution, such as a gold-bearing concentrated copper chloride solution.

State of the art

WO 2010/121317 discloses a method for recovering gold from a gold-bearing concentrate, comprising dissolving gold from the concentrate in an aqueous solution to obtain a gold solution; conducting electrolysis of a gold solution in an electrolytic cell to produce metals to obtain gold material associated with the cathode; leaching the gold material associated with the cathode into an aqueous solution under reducing conditions to obtain a treated solid residue; and melting the treated solid residue to recover gold.

WO 2012/081952 discloses a method for recovering gold and silver from thiosulfate and thiourea solutions by means of an electrolysis process with simultaneous deposition on the cathode and anode.

Various documents are known pertaining to the optimization of the formation of nanofilms, nanoparticles, or functional surfaces. Examples include the following documents.

Kirsi Yliniemi, D. Wragg, B.P. Wilson, H. Neil McMurray, D.A. Worsley, P. Schmuki, K. Kontturi, Electrochimica Acta 88 (2013) p. 278. This document describes the preparation of Pt nanoparticles, where Pb is used as a sacrificial metal; the aim is to create surfaces of Pt nanoparticles from synthetic solutions in order to use them as catalysts in dye sensitized solar cells.

S. Cherevko, N. Kulyk, C.-H. Chung, Nanoporous Pt @ AuxCu100-x by hydrogen evolution assisted electrodeposition of AuxCu100-x and galvanic replacement of Cu with Pt: electrocatalytic properties Langmuir, 28 (2012), p. 3306. This document describes the preparation of nanoporous materials for hydrogen evolution catalysts.

S.R. Brankovic, J.X. Wang, R.R. Adzic, Metal monolayer deposition by replacement of metal adlayers on electrode surfaces, Surface Science, 474 (2001), p. L173. This is the original article on Surface Restricted Redox Substitution (SSRD). This document shows that using Cu as the sacrificial metal produced a lower Pt monolayer, an Ag double layer, and a textured Pd monolayer.

M. Faette, Y. Liu, D. Bertrand, J. Nutariya, N. Vasiljevic, N. Dimitrov. From Au to Pt via surface limited redox replacement of Pb UPD in one-cell configuration, Langmuir, 27 (2011), p. 5650. In this document, the one-pot method was used for HHP.

However, in all these documents, the task is not gold recovery, but only the production of nanostructures / thin films. Moreover, these documents only describe the use of pure synthetic solutions; whereas the present invention provides a method that solves the problem of recovering gold from impurity-containing industrial process solutions when the amount of gold is low compared to impurities.

Brief description of the invention

It is an object of the present invention to provide a method that mitigates the disadvantages of conventional gold recovery methods. The objects of the invention are achieved by a method which is characterized by what is set forth in the independent claims. In addition, embodiments of the invention are disclosed in the dependent claims.

The invention is based on the idea of first carrying out the electrodeposition of copper and possibly gold onto the electrode surface from a solution containing gold, copper and chlorides by applying a suitable external potential or reduction current to the electrodes. After a suitable period of time, the external applied potential or reduction current is switched off or reduced, after which a spontaneous redox substitution step is carried out. During the redox substitution step, the electrode is left in solution, thereby allowing spontaneous replacement of the less noble copper deposited on the electrode surface by ions or complexes of more noble gold contained in the solution. Thus, a gold-rich electrode is obtained.

Traditionally, the more copper there is in the solution from which the gold must be extracted, the more difficult it is to extract the gold. However, the present invention is particularly suitable for recovering gold from solutions that contain large amounts of copper and chloride and very small amounts of gold, because the present invention benefits from the presence of copper in solution. Increasing the amount of copper on the electrode surface gradually creates an improved opportunity for redox substitution. The present method is especially suitable for recovering gold from industrial solution with low gold content and high copper and chloride contents. In addition, the present invention is suitable for recovering gold from solutions that contain a significant amount of impurities such as Na, Ca, K, Pb, Fe, since these impurities do not significantly reduce the amount of recovered gold.

In traditional electroreduction of metals, copper is always inevitably also precipitated in the product if the electrolyte solution has a high copper content and a low gold content. One

- 1 035935 to the proportion of copper in the product can be markedly reduced by the method of the present invention, in which electrodeposition is alternated with a stage of redox substitution, and after the copper is deposited on the electrode, it is replaced with gold.

Another advantage of the present invention is that energy and chemical consumption can be reduced. The spontaneous redox step does not consume or consumes very little electricity, even if a significant portion of the gold is recovered during this step when the applied external potential or current is turned off or markedly reduced. Moreover, the use of extraction chemicals as well as the use of ion exchange resins or precipitation chemicals that are usually required in traditional gold recovery processes can be avoided.

Brief Description of Drawings

The following are the results of the examples with reference to the accompanying drawings, where FIG. 1 shows a comparison of the peak of gold separation (with cyclic voltammetry) after 10 cycles of stages of electrodeposition - redox substitution (EO-OVZ) with different parameters (lines 1-3) and the peak of separation after one stage of electrodeposition (EO) (one stage of EO shows parameters of the traditional type of electroreduction process) (line 4);

in fig. 2A and B, the determination of the degree of gold recovery from an aqueous solution of copper salt (47.3 g / l of copper, 4-5 M chloride and impurities such as 1.4 g / l Zn, 0.5 g / l Pb, 20 mg / L Fe) with 10 ppm (ppm) or 100 ppm gold: (A) the presence of gold enrichment is confirmed by cyclic voltammograms measured in a solution of 20 mM CuCl ₂ +3 M NaCl + 100 ppm Au after 10 EO-HVZ cycles in an aqueous solution of copper salt (EO: -0.27 V, 10 s; HVZ: the potential is turned off until the open circuit potential of 0 V is reached with respect to the NCE (saturated calomel electrode), after which a new stage of EO can be started); (B) an increase for the peak of Au separation in cyclic voltammograms (A);

in fig. 3 shows the purity of the deposits after 10 cycles (example 1) of electrodeposition + redox (EO + RDS) (sample 1) and after one stage of electrodeposition (EO) (one stage of EO shows the parameters of the traditional type of electroreduction) (sample 2); the total deposition time and the applied potential are the same in both cases (sample 1: -0.27 V with respect to LCE 10x10 s = 100 s, sample 2: -0.27 V with respect to LCE, 100 s).

Detailed description of the invention

The present invention relates to a method for recovering gold from a gold-containing concentrated copper chloride solution, comprising:

a) an electrodeposition stage, in which an external potential or reduction current is applied to the electrode located in a gold-containing concentrated solution of copper chloride, whereby copper and possibly gold are deposited on the electrode;

b) a redox substitution stage in which the external potential or reduction current applied in stage (a) is turned off or lowered, thereby allowing spontaneous replacement of the copper deposited on the electrode by gold contained in the solution to obtain an electrode containing gold.

The present method is particularly suitable for recovering gold from industrial solutions with low gold content and high copper and chloride contents. The gold-bearing concentrated copper chloride solution used as the starting material in the present process usually comes from chloride leaching, more specifically, the cyanide-free chloride leaching of gold-bearing mineral (s), gold-bearing ore (s), gold-bearing concentrate (s) ( ore (s), gold-bearing tail (s), gold-copper mineral (s), gold-copper ore (s), gold-copper concentrate (s), waste electrical and electronic equipment (WEEE) and / or other gold-bearing primary or secondary material or materials. The process of the present invention can be carried out after leaching the above materials or during the actual leaching of the above materials. In other words, the gold-bearing concentrated copper chloride solution can also be the leach solution in the actual chloride leaching process, more specifically the cyanide-free chloride leaching of the gold-bearing mineral (s), gold-bearing ore (s), gold-bearing concentrate (s) ), gold-bearing tail (s), gold-copper mineral (s), gold-copper ore (s), gold-copper concentrate (s), waste electrical and electronic equipment (WEEE) and / or other gold-bearing primary or secondary material or materials.

In this context, a concentrated solution means that the concentration of chloride is high enough for the formation of a copper complex in solution, which leads to an increase in the redox potential for leaching gold, usually present in gold-bearing minerals, gold-bearing ores, gold-bearing concentrates, gold-bearing tailings, gold-copper minerals, gold-copper ores, gold-copper concentrates, waste electrical and electronic equipment (WEEE) and / or other gold-bearing primary or secondary material or materials. The chloride concentration is usually greater than 0.5 M, preferably 0.5 to 12 M, more preferably 1 to 6 M, and even more preferably 2 to 5 M.

- 2 035935 concentrated copper chloride solution, copper is usually in the form of bivalent or cuprous ions or chloride complexes in solution. Gold is usually in the form of chloride complexes of monovalent or divalent gold. The gold-bearing concentrated copper chloride solution usually has a high chloride concentration, usually greater than 0.5 M, preferably 0.5 to 12 M, more preferably 1 to 6 M, even more preferably 2 to 5 M. The copper concentration in solution is usually high, usually more than 1 g / l, usually 1-100 g / l, preferably 5-90 g / l, more preferably 10-80 g / l, even more preferably 20-70 g / l.

The concentration of gold in solution is generally low, typically 0.1-100 ppm, more preferably 0.1-20 ppm, even more preferably 0.5-5 ppm. The present invention is particularly suitable for the recovery of gold from feedstocks containing gold as low as 0.1-20 ppm. The solution may also contain bromides in an amount of 0-20 g / L, preferably 1-10 g / L, more preferably 2-6 g / L. In addition, in addition to this, gold-bearing concentrated copper chloride solution usually contains impurity metals such as Fe, Zn, Pb, usually in an amount of less than 2 g / L, while the amount of Ca and Na can usually be relatively high, depending on the source of chlorides ( even more than 80 g / l).

Of note is the fact that gold can be recovered from a gold-bearing concentrated copper chloride solution using the present method. Recovery of gold from source material can be very difficult and economically impractical due to the very low Au concentration. In addition, it is known that copper in a chloride leach solution, i. E. bivalent copper ions or chloride complexes of bivalent copper are able to dissolve Au, and gold dissolves in the form of chloride complexes of gold. However, during the electrodeposition step, copper precipitates, and during the redox step, the deposited copper is replaced by gold from dissolved gold, such as a gold chloride complex.

The method includes, as step (a), an electrodeposition step in which an external potential or reduction current is applied to the electrode. Typically, the potential of the electrode is within the range that allows copper deposition, i.e. less than +0.2 V relative to LCE (saturated calomel electrode), typically +0.2 V to -1.2 V relative to LCE, preferably +0.2 to -0.9 V relative to LCE, and even more preferably -0 , 1 to -0.5 V relative to NCE. The absolute value of the current density (reduction current in the electrodeposition step) is usually 0.1-1000 mA / cm ² , preferably 10-300 mA / cm ² , more preferably 20-200 mA / cm ² , even more preferably 50-100 mA / cm ² . The residence time of the electrodes in solution at an applied external potential or applied reduction current in the electrodeposition step is usually less than 1 hour, usually 1 s to 1 hour, more preferably 1 s to 1 min, and even more preferably 1 to 20 s. It is also possible to interrupt the electrodeposition stage when it is not completed. The electrodeposition step is carried out by a galvanostatic or potentiostatic method. The galvanostatic method means that a direct current is applied. Potentiostatic means that a constant potential is applied. It is possible, but not traditional, to use potentiodynamic or galvanodynamic deposition for copper deposition. Potentiodynamic means that the potential is changed in a limited range of potential, in which copper is deposited on the electrode, and galvanodynamic means that the current is changed in a limited range of current, in which copper is deposited on the surface of the electrode.

The electrode is in electrical contact with a source of external potential or current. The electrodes can be made of any suitable material that is conductive and resistant to chlorides to avoid corrosion. Typically, in the electrodeposition step, copper, and possibly gold, is deposited on a conductive electrode such as a metal oxide, titanium, stainless steel, duplex steel, or Pt cathode. The electrodes can be of any suitable shape such as a plate, ring, sheet, mesh, rod, or any other suitable shape.

The gold-bearing concentrated copper chloride solution can be stationary, agitated or pumped.

In the electrodeposition step, the electrodes are immersed in a gold-containing concentrated copper chloride solution contained in a suitable vessel, pool, tank, etc., and an external potential or reduction current is applied. Also, a gold-bearing concentrated solution of copper chloride can be in the process of leaching. This allows copper and possibly gold to be deposited on the cathode, in other words, under conditions of such a constant potential or current supply, a copper-rich and possibly gold-rich deposited layer is formed on the cathode. If the electrodeposition step is repeated after the redox step, then usually a layer containing copper, gold and possibly impurity metals is formed on top of the previous layer. During the electrodeposition step, typically the majority of the deposited metal is copper and perhaps a minority is gold and impurity metal (s). Usually the thickness of the final product can be measured in micrometers, but more often in millimeters. Copper in chloride solution can oxidize gold from the starting material. Moreover, copper is capable of being deposited in the electrodeposition step, and the redox potential of the solution is such that the redox substitution of gold for copper occurs spontaneously after the electrodeposition step.

- 3 035935 denia.

After step (a), the method includes step (b), which is a redox substitution step in which the applied external potential or reduction current of step (a) is switched off or reduced, whereby spontaneous replacement of the precipitated copper with gold contained in the solution is made possible to obtain an electrode that contains gold, in other words a gold-rich electrode. If the external potential or current is turned off, redox substitution occurs until the predetermined open circuit potential of the copper and gold electrode is reached. This target open circuit potential is selected to be lower than the gold separation potential. Open circuit potential refers to the potential of the electrode when no external potential or current is applied: the open circuit potential is determined by the composition of the solution, the composition of the electrode surface and possible reactions occurring at the electrode. The predetermined value of the open-circuit potential at which the redox step is completed is usually less than 0.8 V with respect to LCE, preferably 0.8-0 V with respect to LCE, more preferably 0.6-0.1 V with respect to LCE, even more preferably 0.3-0.2 V relative to LCE.

Also, the redox step can be completed before this target open circuit potential is reached, and typically this turn-off time is less than 24 hours, preferably 3s-12 hours, more preferably 3s-1h, even more preferably 3s30 min. This time also depends on the mass transfer in the solution and can be changed, for example, by stirring or pumping the solution.

Usually the external potential is turned off. If the external applied potential is reduced, but not turned off, it is usually changed to a value in the range of 0.4-0.7 V with respect to LCE, preferably 0.4-0.6 V with respect to LCE, more preferably 0.5-0.6 V regarding NCE.

Usually, the recovery current is turned off completely. However, it is also possible to reduce the reduction current to a value at which spontaneous redox substitution occurs, usually the absolute value of the current density is less than 50 mA / cm ² , preferably 030 mA / cm ² , more preferably 0-10 mA / cm ² , even more preferably 0-0.5 mA / cm ² .

During the redox stage, copper or possibly impurity metal (s) that were deposited on the electrode surface during the electrodeposition stage donate their electron (s) to the gold ions still in solution, and the copper dissolves at the electrode to go back to solution, and gold is deposited on the electrode instead. Thus, gold can be deposited on the electrode both during the electrodeposition step and during the redox step. The spontaneous redox step does not consume or consumes a very low amount of energy, even if gold is mainly recovered at this step when the applied external potential or current is turned off or markedly reduced. Surprisingly, it has been found that with this method, most of the gold can be recovered during the redox step without the application of external energy (example 3).

After the stage of redox replacement, the electrode is enriched with gold. Surprisingly, it has been found that when the electrodeposition and redox steps are cycled, gold is very efficiently recovered from a highly contaminated concentrated commercial copper chloride solution. For example, only ten times was sufficient, as seen in example 2, in which the solution contained 47.3 g / L Cu, 4-5 M chlorides (and impurities such as 1.4 g / L Zn, 0.5 g / l Pb, 20 mg / l Fe) and Au in the amount of 10 or 100 ppm.

Typically, steps (a) and (b) are repeated sequentially several times (also called cyclic repeating of steps), usually 1 to 100,000 times, preferably 10 to 50,000 times, more preferably 100 to 50,000 times, even more preferably 500 to 5000 to reach the required product containing gold. Thus, after the redox substitution stage (b), a new stage (a) is carried out, in which an external potential or reduction current is applied again, and then a new stage (b) is carried out by turning off the potential or reducing the applied external potential or the applied reduction current ... The parameters used in the second or subsequent stage can be the same or different from the parameters of the first or previous stage, varying within the presented limits.

Typically, steps (a) and (b) are performed for a gold-bearing concentrated copper chloride solution after leaching gold-bearing minerals, gold-bearing ores, gold-bearing concentrates, gold-bearing tailings, gold-copper minerals, gold-copper ores, gold-copper concentrates, waste electrical and electronic equipment (WEEE) and / or other gold-bearing primary or secondary materials. Additional steps (a) and (b) can be performed concurrently with the leaching, i. E. EO + HVZ in leaching.

The present method may also comprise an optional gold recovery step, wherein the electrode obtained in step (b) or the electrode obtained after step (a) or after step (b) after cyclically repeating steps (a) and (b), which contains gold , subjected to hydrometallurgical

- 4 035935 process, pyrometallurgical process, chemical etching, machining or electrochemical etching to recover gold from an electrode. Thus, the process according to the invention can be interrupted at any point during the cyclically repeating steps (a) and (b), and the electrode can be withdrawn after step (a) or after step (b) for a further gold recovery step. Typically, the gold contained in the electrode is recovered by leaching the deposited gold from the electrode into a solution capable of dissolving gold, such as chloride, cyanide, thiosulfate, thiourea, glycine, and recovering the gold from the solution by precipitation or electroreduction, or any other suitable method known a person skilled in the art.

Examples of

Example 1.

Studied the extraction of gold from a synthetic gold-containing solution of copper chloride (20 mM CuC1 ₂ + 3M NaCl + 100 ppm Au) using 10 cycles of stages (EO + ODS) electrodeposition (EO) and redox substitution (ODS). A Pt plate (0.32 cm2) was used as a gold collection electrode (cathode), another Pt plate (0.32 cm2) was used as a counter electrode (anode), and a standard calomel electrode was used as a reference electrode.

The EO step was carried out at a potential value of either -0.4 V with respect to LCE, or -0.27 V with respect to LCE, and the EO time was either 10 s or 5 s. The stage of redox substitution, during which the external applied potential was turned off and the deposited copper was spontaneously replaced by gold, was carried out until the open-circuit potential of the electrode (cathode) reached 0 V with respect to the LCE.

As a comparison, one gold extraction was carried out using one electrodeposition step at a deposition potential of -0.27 V with respect to LCE and a time of 100 s.

Immediately after 10 cycles of EO-VZ stages, the cyclic voltammogram was measured in the same solution (25 mV / s, -0.2 V ^ 1.1 V ^ -0.7 V ^ -0.2 V with respect to NCE) and compared the sizes of the Au separation peak in the region 0.75-0.80 V relative to NCE; the size of the peak of the separation indicates the amount of gold on the electrode. These peaks are shown in FIG. 1.

Confirmation of the extraction of gold from synthetic solutions (20 mM CuCl ₂ + 3M NaCl + 100 ppm Au) was found after the stages of EO + VZ (curves 1–3) and one stage of OE (curve 4). Observed the following:

curve 1 versus curve 2: the effect of the electrodeposition potential, a greater decrease in the EO potential (lower potential, -0.4 V, compared to -0.27 V relative to the NCE) increased the amount of gold recovered;

curve 1 versus curve 3: the effect of the electrodeposition time, the longer the deposition time increased the amount of gold recovered;

curve 2 versus curve 4: the effect of the HVD stage, more gold was recovered with the OE + HVD than with one EO stage, even when the applied energy was the same in both cases (the same deposition time, i.e. 10x10 s ( OE + HVZ) or 100 s (one OE stage) and the same deposition potential);

During the HVD stage, no external energy was required to carry out the redox substitution (the external applied potential was turned off during the redox substitution stage, and the HVD stage was completed when the open circuit potential reached 0 V relative to the LCE, after which a new EO stage begins).

Example 2.

In addition, gold recovery from an industrial process solution (HydroCopper ™ process) containing 47.3 g / L copper, 4-5 M chloride (and impurities such as 1.4 g / L Zn, 0.5 g / l Pb, 20 mg / l Fe) and 100 or 10 ppm gold. Carried out 10 cycles of stages (EO + OVZ) electrodeposition (EO) and redox substitution (OVZ). A Pt plate (0.32 cm2) was used as a gold collection electrode (cathode), another Pt plate as a counter electrode (anode), and a standard calomel electrode (NCE) as a reference electrode. The EO step was carried out at -0.27 V relative (NCE) and the duration of each EO step was 10 seconds. The stage of redox substitution, during which the external applied potential was turned off and the deposited copper was spontaneously replaced by gold, was carried out until an open-circuit potential of 0.2 V with respect to LCE was reached.

Immediately after 10 cycles of the OE-HVZ steps, the electrodes were removed from the HydroCopper ™ solution and rinsed with water. After that, the electrodes were placed in a solution of 20 mM CuCl ₂ + 3M NaCl + 100 ppm Au, the cyclic voltammogram was measured (25 mV / s, -0.2 V ^ 1.1 V ^ -0.7 V ^ -0.2 V relative to the NCE) ... Determined the size of the peak of the Au separation in the region of 0.75-0.80 V relative to the LCE, and they confirmed the enrichment of gold on the electrode surface. Such a cyclic voltammogram is shown in FIG. 2a, and the increase for the potential range of the gold separation peak is shown in FIG. 2b.

FIG. 2 shows that when using the EO-OVZ method, it is possible to extract gold from industrial solutions of the hydrometallurgical method, which contain high concentrations of me- 5 035935 di (“47.3 g / l), high chloride concentrations (4-5 M), low concentration of gold (100 or 10 ppm) and impurities. This is particularly notable because most of the gold was recovered during the redox stage in the absence of external energy applied.

Example 3.

The Au recovery was compared for samples obtained by 10 stages of electrodeposition + redox substitution (sample 1) and one stage of electrodeposition (sample 2), performed in a solution of 20 mM CuCl ₂ + 3M NaCl + 100 ppm Au.

The wt% Au (depending on Cu) was determined by SEM-EMF study (scanning electron microscope, LEO 1450 VP, Germany - energy dispersive X-ray spectroscopy, INCA software, UK) using the average of 20 points of the EMF spectra (each spectrum was measured in various places on the electrode surface). Before the study, the samples were first washed with distilled water and dried in air at room temperature. The research results are presented in Fig. 3.

Gold recovery parameters are presented for both samples below.

Sample 1.

Electrodeposition stage: -0.27 V relative to NCE, 10 sec.

The stage of redox substitution: the applied external potential was turned off, the stage of the redox was carried out until the potential of the open circuit of 0 V was reached with respect to the LCE.

Number of cycles: 10.

The total application time of the external potential: 10x10s = 100s.

Sample 2.

Electrodeposition: -0.27 V relative to NCE, 100 sec.

The stage of redox substitution is absent.

Number of stages: 1.

Total application time of external potential: 100 s.

FIG. 3 shows that when using the method according to the invention, surprisingly, the gold content in the deposited layer is definitely higher than when using the same total deposition time and potential application in one electrodeposition step.

One skilled in the art will appreciate that as technology advances, the concept of the invention can be implemented in various ways. The invention and its embodiments are not limited to the examples described above, and the embodiments may be varied within the scope of the claims.

Claims (22)

CLAIM 1. A method of extracting gold from a gold-containing concentrated solution of copper chloride, including: a) an electrodeposition stage, in which an external potential or reduction current is applied to the electrode located in a gold-containing concentrated solution of copper chloride, whereby copper is deposited on the electrode; b) a redox substitution stage in which the external potential or reduction current applied in stage (a) is turned off or lowered, thereby allowing spontaneous replacement of the copper deposited on the electrode by gold contained in the solution to obtain an electrode containing gold. 2. The method according to claim 1, wherein in the electrodeposition step a) gold is additionally deposited together with copper. 3. A method according to claim 1 or 2, wherein the gold-bearing concentrated copper chloride solution comes from chloride leaching, usually cyanide-free chloride leaching, gold-bearing mineral (s), gold-bearing ore (s), gold-bearing concentrate (s) (s), gold-bearing tail (s), gold-copper mineral (s), gold-copper ore (s), gold-copper concentrate (s), waste electrical and electronic equipment (WEEE) and / or other gold-bearing primary or secondary material or materials. 4. A method according to any one of the preceding claims, wherein the gold-containing concentrated copper chloride solution has a chloride concentration of more than 0.5 M, preferably 0.5 to 12 M, more preferably 1 to 6 M, even more preferably 2 to 5 M ... 5. A method according to any one of the preceding claims, in which the gold-containing concentrated copper chloride solution has a copper concentration of more than 1 g / l, preferably 1-100 g / l, more preferably 5-90 g / l, even more preferably 10-80 g / l , even more preferably 20-70 g / l. 6. A method according to any one of the preceding claims, wherein the gold-containing concentrated copper chloride solution has a gold concentration of 0.1-100 ppm, preferably 0.1-20 ppm, more preferably 0.5-5 ppm. 7. A method according to any one of the preceding claims, wherein gold and copper are deposited on a conductive electrode such as a metal oxide, titanium, stainless steel, duplex steel or Pt cathode. - 6 035935 8. A method according to any of the preceding claims, wherein the electrode (s) are (are) in the form of a plate, ring, sheet, mesh or rod. 9. A method according to any of the preceding claims, wherein the potential in the electrodeposition step is less than +0.2 V relative to the saturated calomel electrode (SEC), preferably from +0.2 to -1.2 V relative to the NCE, more preferably from +0 , 2 to -0.9 V relative to LCE, and even more preferably from -0.1 to -0.5 V relative to LCE. 10. A method according to any one of the preceding claims, in which the reduction current in the electrodeposition step has an absolute value of the current density of 0.1-1000 mA / cm ² , preferably 10300 mA / cm ² , more preferably 20-200 mA / cm ² , even more preferably 50-100 mA / cm ² . 11. A method according to any of the preceding claims, wherein the residence time in step (a) is 1 second to 1 hour, preferably 1 second to 1 minute, more preferably less than 30 seconds, most preferably 1 to 20 seconds. 12. A method according to any one of the preceding claims, wherein the electrodeposition step is carried out by a galvanostatic, potentiostatic, potentiodynamic or galvanodynamic method. 13. A method according to any of the preceding claims, wherein the applied external potential is switched off in the redox substitution step (b). 14. A method according to any one of the preceding claims, in which the applied external potential during step (b) is changed to a value of 0.4-0.7 V relative to LCE, preferably 0.4-0.6 V relative to LCE, more preferably 0, 5-0.6 V relative to NCE. 15. A method according to any one of the preceding claims, in which the recovery current is turned off or reduced to an absolute value of current density, usually less than 50 mA / cm ² , preferably 0-30 mA / cm ² , more preferably 0-10 mA / cm ² , even more preferably 0-0.5 mA / cm ² . 16. A method according to any one of the preceding claims, wherein the redox substitution step (b) is completed when the open circuit potential reaches a predetermined value, typically less than 0.8 V with respect to LCE, preferably 0.8-0 V with respect to LCE, more preferably 0.6-0.1 V relative to LCE, even more preferably 0.3-0.2 V relative to LCE. 17. A method according to any one of the preceding claims, wherein the redox step (b) is completed after a predetermined period of time to allow replacement of copper by gold, typically less than 24 hours, preferably 3 seconds to 12 hours, more preferably 3 seconds to 1 hour , even more preferably 3 seconds to 30 minutes. 18. A method according to any one of the preceding claims, in which steps (a) and (b) are repeated sequentially from 1 to 100,000 times, preferably from 10 to 50,000 times, and more preferably from 100 to 50,000 times, even more preferably from 500 to 5000 times ... 19. The method according to any one of the preceding claims, wherein the electrode obtained in step (b) or the electrode obtained after step (a) or after step (b), after cycling steps (a) and (b), containing gold , is subjected to a hydrometallurgical process, a pyrometallurgical process, chemical etching, machining, or electrochemical etching to extract gold from the electrode. 20. A method according to any one of the preceding claims, wherein the gold contained in the electrode is recovered by leaching the precipitated gold from the electrode into a solution capable of dissolving gold such as chloride, cyanide, thiosulfate, thiourea, glycine, and the dissolved gold is recovered from solution by precipitation or electroreduction. 21. A method according to any one of the preceding claims, wherein the gold-bearing concentrated copper chloride solution is stationary, agitated or pumped. 22. The method according to any one of the preceding claims, in which steps (a) and (b) are carried out after leaching or during leaching of gold-bearing mineral (s), gold-bearing ore (s), gold-bearing concentrate (s) ( ore (s), gold-bearing tail (s), gold-copper mineral (s), gold-copper ore (s), gold-copper concentrate (s), waste electrical and electronic equipment (WEEE) and / or other gold-bearing primary or secondary material or materials.