TITLE OF THE INVENTION Procedure for producing germanium concentrate from metallurgical residues FIELD OF THE INVENTION The invention relates to a procedure for producing germanium concentrate from metallurgical residues, in particular, from residues containing copper, iron, lead, and germanium, and which can optionally contain elements such as arsenic, antimony, and bismuth. In a more specific aspect, metallurgical residues are powders from a metal smelting process. In an even more specific aspect, metallurgical residues are powders from a copper smelting process. In an even more specific aspect, metallurgical residues, or in particular smelting powders, contemplate materials which have already been subjected to a leaching process, such as sulfuric leaching. In a broad aspect, the germanium concentrate may be understood as a germanium- rich liquid fraction, consisting mainly in germanium tetrachloride, or in a solid germanium concentrate which, in a more specific aspect may relate to germanium dioxide. In the present disclosure, any metallurgical residue which has been subjected to prior leaching processes shall be considered as sludge. State of the art Copper leaching The copper in the sludge is mainly composed of species such as ferrites and/or spinels in the form of CuFe204 as zinc, ZnFe204 and a relevant part of iron, FeFe204. Leaching of these species is based on temperature, acid concentration and residence time, as described in the study by B. S. Boyanov, et al. in World Academy of Science, Engineering and Technology, Vol 9, 2015, 1592-1598, who carried out a synthetic ferrite leaching study of zinc, copper and cadmium, evaluating the previously mentioned variables. The results of this study show that ferrites are better dissolved in HCI and H2504, at elevated temperatures and high acid concentrations. At high acid concentrations it is observed that copper leaching has an asymptotic behavior regarding the leaching temperature, which, once the 60 minutes reaction time has elapsed in 1 Date recue / Date received 2021-12-20 sulfuric media, reaches copper leaching yields above 90% for the range of temperatures between 85 and 90 C. Lead leaching World lead consumption for the year 2011 was above 10 million tons, of which about 80% of said lead was meant for the manufacturing of acid and lead batteries. These batteries contain lead amounts in the form of Pb, Pb02 and PbSO4. The most traditional way of recovering lead is the pyrometallurgical route, which is characterized by the addition of a reducing agent, such as carbon powder, iron scrap and sodium oxalate. The operation is carried out in ovens at temperatures above 1000 C, which results in a high demand of energy process He et al., Minerals 7, no. 6 (2017): 93. On the other hand, the hydrometallurgical route for recovering lead allows working at reduced temperatures, reducing energy consumption, and in turn sulfur dioxide, which is characterized for being a gas harmful for the environment, is not produced. The hydrometallurgical route uses desulphurizing agents such as sodium carbonate, ammonium carbonate, sodium bicarbonate, ammonium bicarbonate, sodium hydroxide, sodium citrate, acetic acid, sodium acetate, among others. The aim of these processes is to exchange the ion sulphate for other anions in order to form insoluble salts. Once recovered, lead salts such as lead citrate may be calcined in order to produce lead oxide (Zarate-Gutierrez and Lapidus, Hydrometallurgy 144 (2014): 124-128.). Desulphurization with citrate In the particular case of the use of citrates, the citric acid and sodium citrate mixture is beneficial for leaching lead sulfate and the subsequent crystallization of lead citrate. Lead leaching in citrate solutions The solubility product constant of anglesite at 20 C is 6.31- 10-7, indicating that PbSO4 solubility .. is quite reduced. However, in the presence of citrate concentrated solutions, lead forms a series of soluble complexes. In solutions having 0.12 M Pb2 , a great variety of citrate complex species are present in solution in the pH range of 4.6 to 11.5. At a pH lower than 4.6 the presence of lead sulphate is predominant, while at pH higher than 11.5 the lead hydroxide presence is dominant. .. He et al., Minerals 7, no. 6 (2017): 93, studied lead leaching of a paste with a lead sulphate to water weight ratio of 1:10, by the addition of 650 g/L sodium citrate at 35 C. These conditions allowed converting more than 99% lead sulphate into lead citrate once 60 min reaction time had elapsed. The increase in temperature up to 95 C, at a sodium citrate concentration of 300 2 Date recue / Date received 2021-12-20 g/L allowed obtaining an efficiency near 99% once 60 min reaction time had elapsed. However, when introducing citric acid to the mixture a decrease in the lead citrate production was observed. The optimum pH for producing lead citrate was within the range of 6 to 7. At a pH of 5.5 using citric acid and ammonium agents, elevated lead leaching efficiencies are also obtained from acid and lead batteries. Within the pH range of 5.2 to 5.5 the presence of trihydrate lead citrate aPb3(C61-1507)2H3H20]) was reported as the main species. At higher pH within the range of 8 to 10 the lead recovery as citrate salt is lower due to the formation of lead hydroxide. When lead residues are rich in oxides such as Pb0 and Pb02, leaching is performed with a citric acid to lead oxide (II) and (IV) molar ratio of 1:1 and 4:1 at 20 C between 15 and .. 60 min reaction, reaching leaching efficiencies higher than 99% by weight, obtaining Pb(C6H607)-1-120 as the main species (Sonmez and Kumar, Hydrometallurgy 95, no. 1-2 (2009), 82-86.) Pulp density is another import parameter for lead leaching with citrate solutions. Within the range of 10 to 50 g/L anglesite pulp, leachates with a sodium citrate solution 1 M, pH 7 at 600 rpm and 25 C, higher levels of lead extraction of 90 to 94% were reached with a pulp concentration of 10 g/L. At greater pulp concentration, lesser was the extracted lead amount. Therefore, hydrometallurgical desulphurization processes are affected by the citrate ion diffusion in the lead paste within the reactor due to the elevated density of lead paste. In this context it is key to design reactors maximizing the mass transfer in the system. Technology based on lead recovery from lead waste using citric acid has been developed by Cambridge Enterprise Limited (W02008056125A1).This technology basically comprises treating lead residues comprising lead oxide (II), lead oxide (IV) and lead sulphate with a citric acid solution, and which can be alternatively treated in combination with sodium citrate at a pH varying within the range of 1.4 to 6. Eventually, it is possible to add hydrogen peroxide in basic environment as reducing agent in order to accelerate the lead oxide (IV) leaching reaction so as to produce lead citrate (Sonmez and Kumar, Hydrometallurgy 95, no. 1-2 (2009), 82-86.). The present invention differs from application (W02008056125A1) in that the pH required for leaching varies from 5.33 to 8.8, where preferably a pH equal to 7 is used. Additionally, the present invention presents recirculating the citrate solution obtained after a precipitation step with sodium carbonate, so as to again leach output metallurgical residue from the sulfuric leaching step. 3 Date recue / Date received 2021-12-20 Germanium leaching Germanium is a metal which is widely used in the field of optical fiber, infrared fiber, photovoltaic cells, and aeronautic, aerospace and military industry, among others. In general, germanium is not abundant in the Earth's crust, since it constitutes between 1 ยจ 7 ppm of Earth's crust, with a total estimated amount of 8600 tons. Germanium is usually associated with copper, lead, zinc, and carbon deposits, whereas deposits with an elevated content of germanium are limited. Most of the germanium is recovered from vapors of lignite subjected to pyrometallurgical processes, and from lead-zinc mineral smelting. However, pyrometallurgical processes have lost importance every time they generate environmental issues associated with germanium (II) oxide and germanium sulphide volatility. There are various methods for the recovery of germanium from electrolytic solutions of zinc, from which tannin precipitation, germanium tetrachloride distillation, flotation, activated carbon adsortion, precipitation, solvent extraction and chelating resin adsortion stand out (US 455332). Germanium is usually present in the form of germanic acid Ge(OH)4, the most predominant species being within the pH range of pH 1 to 8, whereas between pH 9 to 13 the most predominant species is GeO(OH)31- and at pH greater than 13, the dominant species is Ge02(OH)22-. The first dissociation constant of germanic acid is 4,9-10 mol.L- 1 (log KA = 9,31) (Wood and lain, Ore Geology Reviews 28, no. 1(2006): 57-102.). Ge(OH)44-GeO(OH)3- +1-1 log Kdiss = -9,31 GeO(OH)3-Ge02(OH)22- log Kdiss = -21,9 Acid leaching Germanium may be leached using H2504, at temperatures of between 40 and 60 C, at a H2504 concentration of 100 g/L for a period of 30 min and with a solid:liquid ratio of 1:4, recovering 78% germanium. At higher temperatures, in the order of 85 C, and at a H2504 concentration of 150 g/L and a residence time of 1 h, collective leaching of different metals is produced, wherein the extraction of germanium was of 92.7% (Rutledge et al., Metals 5, no. 3 (2015): 1520-1542.). Patent application CN108486390A describes a process for separating germanium and gallium from a germanium- and gallium-containing material. In a first step, the germanium and gallium material is added to a solution of 50 to 150 g/L H2504 at a ratio of 5 to 10% w/w, and subsequently adjusted to a pH between 1 and 3. The leaching solution is neutralized at pH 1 to 3, for the subsequent addition of zinc powder to the neutralized liquid at a temperature of 40-80 C, in order to obtain germanium concentrates and a liquid solution. To this liquid solution 4 Date recue / Date received 2021-12-20 is again added zinc powder at a temperature of 40-80 C, in order to obtain gallium residues and a liquid solution Alkaline leaching Patent application CN108300876A describes a method for leaching gallium and germanium from slags of processes for obtaining zinc. In a first step, the slag is milled to a size of 50-100 microns, then 0.1-1 mol/L H2SO4 solution is added in a liquid-solid ratio of 4- 10: 1 ml/g, at a leaching temperature of 25-80 C, stirring at 100-600 rpm for 0.25-4 h. Then the liquid-solid separation is carried out to obtain leaching residues with H2SO4 to which a solution of 0.2-2 mol/L hydrogen peroxide is added at a liquid-solid ratio of 4-10: 1 mL/g, adding 0.1-1 mol / L NaOH to adjust the pH of the leaching solution to 5.0 - 8.0. This alkaline leaching is carried out at 25-80 C, stirring at 100-600 rpm for 0.25-4 h, in order to obtain a germanium-rich leaching solution. In the case of the present invention, in order to be able to leach germanium values, the sulfuric leaching and citric leaching steps are necessary in order to remove the elevated levels of lead in the metallurgical residue and thus increase the content of germanium in the .. residue due to the loss of metallurgical residue mass in the citric leaching step. Further, the presence of lead in the metallurgical residue by generating a process such as the one of the application would result in a greater consumption of soda, due to the conversion of lead sulfate into lead hydroxide, which would affect germanium leaching yield. Ion exchange Subsequent to the leaching step, the obtained germanium must be concentrated by different alternatives such as solvent extraction, precipitation with chelating agents or ion exchange. For the present invention, the ion exchange step has been considered every time since it is the one with better recovery levels and it also allows increasing the germanium concentration ratio vs. other metals present in the leaching solution such as lead, aluminum, silicon and arsenic. Patent U54525332 describes the adsortion of germanium-containing solutions in ion exchange resins consisting of a polymer having functional groups selected from secondary, tertiary and quaternary ammonium groups, which have a relative selectivity of germanium to antimony of 50:1, followed by an elution of germanium collected by the resin in an aqueous medium. The present invention makes use of a resin containing N-methylglucamines as functional group. Patent U54525332 does not specify that the charge solution may contain silicon. In the application examples of patent U54525332, the charge is carried out with acid or slightly acid solutions, and not with alkaline solutions, as shown by the present invention. By being an element belonging to the same group as germanium, silicon may interfere when recirculating 5 Date recue / Date received 2021-12-20 charge solutions used within the process. In the same way, the elution of the resin used in the examples of patent US4525332 is carried out with H2SO4 or sodium hydroxide, depending of the resin used, in contrast with the elution with HCI which is carried out herein, and which is necessary for the subsequent step of germanium tetrachloride distillation. Further, the present invention differs from patent US4525332 in that the latter does not teach how to remove silicon from alkaline solutions in order to recirculate the solution as a leaching medium of metallurgical residues to obtain germanium. Patent application GB933563A teaches the processing of aqueous, neutral or slightly acid solutions of germanium in ion exchange resins containing hydroxy phenyl groups in which .. germanium is collected, for it to be later eluted with hydrochloric solutions on 7 N for it to be later distilled and the germanium tetrachloride hydrolyzed to produce germanium dioxide. Patent application GB933563A does not teach how to carry out the charge of strongly alkaline solutions with the presence of silicon. Since there is silicon present in solution, the neutralization of the solution in order to carry out the charge of germanium in the resin is not obvious, since when lowering the pH the silicon would precipitate and drag the germanium. In this scenario, it is necessary to carry out the charge without the prior precipitation and remove the silicon once the solution has passed through the column and is deficient of germanium. In addition, unlike patent application GB933563, in this invention the elution may be carried out with solutions with Ge concentrations of less than 6 N with no evidences of considerable loss of germanium. Germanium distillation Powell et al. J. Appl. Chem. 1951, 541-551, teaches the leaching of smelting powders with HCI, in order to generate germanium tetrachloride in situ which could be distilled at a temperature of 84 C. One of the problems of this method is the presence of arsenic trichloride .. because, even though it boils at 130 C, its vapor pressure at 84 C is high enough so as to co- distill with germanium tetrachloride. In this sense the present invention differs from the teachings of Powell in the sense that there is a series of prior leaching steps and ion exchange separation which prevent elements such as arsenic to be present in elevated concentrations which interfere with germanium distillation. Patent U53102786 teaches a continuous process for purifying germanium tetrachloride using an HCI solution with a minimum concentration of 6 N, and keeping the column at a temperature of between 83 and 110 C. The present invention differs from US3102786 in that the distillation may be carried out at acid concentrations of less than 6 N, allowing to distill germanium in an effective way with distillation rates over 95%. 6 Date recue / Date received 2021-12-20 Patent US2811418 teaches a process for purifying germanium tetrachloride, using an HCL solution, of 12 N concentration, and saturated with chlorine gas, allowing the mixture to separate in two phases, wherein the heavier phase contains purified germanium tetrachloride. The present invention differs from US2811418 in that the distillation may be carried out at acid concentrations lower than 12 N, in particular lower than 5 N, allowing to distill germanium in an effective way with distillation rates over 95%, minimizing arsenic drags. Germanium hydrolysis Patent US3455645 discloses a process for the production of amorphous germanium dioxide, characterized in that it precipitates germanium present in the aqueous solution wherein the pH is at least 5 and at most 9. In particular, the experiments disclosed by US3455645 teach about the addition of germanium tetrachloride to a solution containing 10 parts NaOH by 90 parts water up to a pH lower than 8, or preferably lower than 6. Patent US3455645 differs from the present invention in that the distillation solutions obtained are sent directly to a cooling reactor wherein germanium dioxide precipitation is verified, with no need of controlling the pH at the values stated by US3455645. James E. Hoffmann in Extracting and Refining Germanium, Journal of Metals, June 1987, 42- 45, states that at HCI concentrations of less than 5.5, germanium is mainly found as germanic acid, and that 3 grams of water are enough to hydrolyze 1 g germanium with a yield of 95%. In addition, it states that it is preferable for the precipitation to be carried out at a temperature close to 0 C, and that it is possible to use germanium dioxide to act as center of nucleation of germanium precipitation. The present invention shows that it is possible to obtain elevated germanium precipitation yields with no need to use germanium dioxide as a seed to verify germanium precipitation. The present invention proves that by using sufficiently concentrated solutions of germanium it is possible to precipitate germanium dioxide, and that low HCI .. concentrations negatively affect germanium dioxide precipitation process compared to HCI concentrations close to 3.7 N (135 g/L HCI). Description of the figures Figure I shows the process diagram of the procedure disclosed by the present invention. Figure II shows the distillation curve of germanium from ionic exchange solutions. Figure III shows the second distillation curve of germanium from primary distillation solutions. Second distillation refers to a distillate solution which has been collected following a first distillation cycle. 7 Date recue / Date received 2021-12-20 Figure IV shows the third distillation curve of germanium from secondary distillation solutions. Third distillation refers to a distillate solution which has been collected following a second distillation cycle. Description of the invention In a broad sense, the invention describes a procedure for the production of germanium from metallurgical residues. In one preferred option, the invention describes a procedure for the production of germanium tetrachloride. In a still more preferred option, the invention describes a procedure for the production of a solid-state germanium concentrate. In a still more preferred option, the invention describes a procedure for producing technical- grade germanium dioxide, with a concentration ranging from 60 and 70%. In one broad aspect, the invention describes a procedure for producing germanium concentrate from metallurgical residues, in particular, from residues containing copper, iron, lead, silicon, and germanium, and which can optionally contain elements such as arsenic, antimony and bismuth, characterized in that it comprises: a step (i) of copper leaching with a first acid solution (2) of the metallurgical residue (1), in order to obtain a first leaching solution rich in copper and iron, and optionally arsenic, antimony and bismuth (3) and a first leached sludge having a content reduced in copper and iron, and optionally reduced in arsenic and rich in lead, silicon and germanium (4), a step (ii) of leaching the first leached sludge (4) wherein said first leached sludge (4) is processed with a first solution of a carboxylic acid salt (5), in order to obtain a second leached sludge deficient of lead (6) and a second leaching solution rich in lead (7), a step (iii) of alkaline leaching of the second leached sludge, wherein a base (8) is added in order to form an alkaline leaching solution, in order to obtain a third leached sludge having a content reduced in silicon and germanium (9), and a third leaching solution rich in germanium and silicon, and optionally arsenic (10), a step (iv) of charging the third leaching solution rich in germanium and silicon (10), and optionally arsenic in an ion exchange column, wherein the germanium is captured by the resin, in order to obtain a fourth alkaline solution deficient of germanium and rich in silicon (11), 8 Date recue / Date received 2021-12-20 a step (v) of washing the ion exchange column, which is carried out with water (12), wherein a fifth solution of column charge wash (13) is obtained, a step (vi) of eluting the ion exchange column, which is carried out with an HCI solution (14), in order to obtain a sixth elution solution rich in germanium (15), a step (vii) of distillation, wherein the sixth elution solution rich in germanium (15) is distilled in order to obtain a seventh solution of germanium (16) and an eighth solution deficient in germanium (17), and a step (viii) of hydrolysis, wherein the seventh solution of germanium (16) is contacted with a solution of water (18) to produce a first germanium dioxide concentrate (19) and a ninth solution deficient of germanium (20). In one preferred optional, the metallurgical residue to be processed is powder obtained by a metal smelting process or powder obtained by a copper smelting process. In an even more preferred option, the metallurgical residue has been subjected to a copper leaching process. In an even more preferred option, said metallurgical residue has been subjected to leaching with H2SO4. In one preferred option, the metallurgical residue to be processed comprises the mineral species anglesite, covelline, cuprospinel in the form of Cu0Fe203, zinc spinels in the form of Zn0Fe203, magnetite, iron oxide (III), pirite, scorodite, mucovite, kaolinite and lead sulphate (II). In an even more preferred option, the copper contained in the metallurgical residue is present as copper sulphate, calcosine, covelline and cuprospinel in the form of Cu0Fe203. In an even more preferred option, the copper contained in the metallurgical residue is present in at least 50% in the form of cuprospinel in the form of Cu0Fe203. In one preferred option, the silicon contained in the metallurgical residue is present as muscovite and kaolinite. In another preferred option, the lead contained in the metallurgical residue is present as lead sulphate (II), galena or lead oxide (II). In an even more preferred option, the lead is in at least 95% as lead sulphate (II). 9 Date recue / Date received 2021-12-20 In one preferred option, the first H2SO4 solution of step (i) may comprise H2SO4 and/or a refinery effluent. In one preferred option, step (i) is performed at a H2SO4 concentration of between 150 and 300 g/L, more preferably at a concentration of H2SO4 of 250 g/L. In one preferred option, step (i) is performed at a temperature of between 50 and 130 C, more preferably at a temperature of 85 C. In one preferred option, step (i) is performed for a period of between 3 and 12 hours, more preferably for a residence time of 6 hours. In one preferred option, step (i) is performed at a solid concentration of between 5 and 20% w/w, more preferably at a solid concentration of 15% w/w. In one preferred option, in step (ii) of leaching, the carboxylic acid salt is sodium citrate. In one preferred option, in step (ii) the sodium citrate solution has a molar concentration of sodium citrate between 0.5 and 1 M. In one preferred option, in step (ii) the first leached sludge is fed to the sodium citrate solution in a mass ratio of 1:9. In one preferred option, step (ii) is performed at a temperature of between 20 and 60 C, more preferably at 40 C. In one preferred option, step (ii) is performed for a residence time of between 1 and 23 h. In one preferred option, step (ii) is performed at a pH of between 5.3 and 8.8, more preferably at a pH of 7.0. In one preferred option, in step (ii), the corresponding acid of the carboxylic acid salt is added for adjusting the pH. In an even more preferred option, in step (ii), a citric acid is added for adjusting the pH. In an even more preferred option, the pH adjustment in step (ii) is performed with a citric acid solution of between 600 and 900 g/L. In one preferred option, step (iii) is a germanium leaching step. In one preferred option, the second base used in the leaching of step iv is selected between Mg(OH)2, KOH or NaOH. Date recue / Date received 2021-12-20 In one preferred option, the base added in step (iii) is added in a ratio of between 5 and 10% w/w regarding the total mass of alkaline leaching solution, more preferably in a ratio of 6.0% w/w. In one preferred option, the leaching reaction of step (iii) is performed at a temperature of between 70 and 150 C, more preferably at a temperature of 130 C. In one preferred option, the leaching reaction of step (iii) is performed for a residence time of between 1 and 12 hours, more preferably for a residence time of 3 hours. In one preferred option, step (iv) is performed with a resin with a nitrogen atom group (N-donor group). .. In one preferred option, step (iv) is performed charging the third leaching solution rich in germanium and silicon at a ratio of between 2 and 3 bed volumes. In an even more preferred option, step (iv) is performed charging the third leaching solution rich in germanium and silicon at a ratio of 10 bed volumes. In one preferred option, step (v) is performed charging the fourth solution of charge wash at a ratio of between 5 and 15 bed volumes. In one preferred option, step (vi) of elution is performed with a HCI solution. In an even more preferred option, step (vi) of elution is performed with an HCI solution at a concentration of between 2 and 8 N, more preferably 6 N. In one preferred option, step (vi) is performed by charging the HCI solution at a ratio of between 1 and 5 bed volumes, more preferably at a ratio of 3 bed volumes. In another preferred option, the fourth alkaline solution deficient of germanium is subjected to a silicon removal process. In another preferred option, in said silicon removal process, slaked lime or aluminum sulphate is added. In an even more preferred option, in said silicon removal process, slaked lime is added. In an even more preferred option, slaked lime is added at a molar ratio of 1:1 with respect to the silicon contained in the fourth alkaline solution deficient of germanium, in order to generate a regenerated alkaline solution and a solid consisting of calcium silicate. 11 Date recue / Date received 2021-12-20 In another preferred option, the silicon removal step is performed at a temperature of between 20 and 90 C. In an even more preferred option, the regenerated alkaline solution is recirculated to step (iii) of alkaline leaching. In another preferred option, step (vii) of distillation is performed at a temperature of between 86.5 C and 107 C, and at a bulb temperature of between 86.5 and 108 C. In another preferred option, the seventh germanium solution is redistilled between 1 to 5 times in order to produce a concentrated germanium solution and a distilled HCI solution. In an even more preferred option, the seventh germanium solution is redistilled 3 times in order to produce a concentrated germanium solution and a distilled HCI solution. In one preferred option, the distilled HCI solution is recirculated at a previous distillation step with the purpose of increasing HCI concentration at the entry to the distiller. In another preferred option, the concentrated germanium solution is contacted with deionized water at a volumetric ratio of between 1:1 and 1:6 to precipitate germanium as a germanium concentrate. In an even more preferred option, said germanium concentrate is germanium dioxide. In an even more preferred option, the concentrated germanium solution that is contacted with deionized water in step (viii) is performed at a temperature of between 2 and 15 C. In another preferred option, the concentrated germanium solution sent to the hydrolysis step has a germanium concentration between 8.1 and 24.8 g/L. In another preferred option, the concentrated germanium solution sent to the hydrolysis step has a HCI concentration between 55 and 135 g/L. In one preferred option, the first leaching solution rich in copper is sent to a copper leaching process of smelting powders. .. In one preferred option, the first leaching solution rich in copper is sent to an arsenic abatement process. In one preferred option, the arsenic abatement process is selected from those contemplating the ferric arsenate production. 12 Date recue / Date received 2021-12-20 In an even more preferred option, the arsenic abatement process is a scorodite production process. Application examples The examples below should be considered as embodiments of the present invention and in no case should they be considered as limiting thereof, since different adaptations which may be performed thereto shall be covered within the subject matter claimed by this invention. Sulfuric leaching Examples 1 to 7 Between 2.550 and 2.850 g of a sulfuric acid solution with a con concentration of between 150 and 250 g/L of H2SO4 were prepared, which were arranged in a 5 L glass reactor, wherein the sludge previously subjected to a copper leaching process was added to a solid content of between 5 and 10% w/w. Mineralogy of said sludge is shown in Table 1. The reactor was stirred at 300 rpm for 3 to 6 hours at 85 C. Once the reaction time is ended, the pulp was filtered in a Buchner system. Results are shown in Table 2. Table 1. Sludge mineralogy Species Unit Value Pbso4 12.84 PbS 0.1 POO 0.1 CuSO4 2.54 Cu2S 0.63 CuS 4.02 CuO 0/1 Cu0Fe203 15.09 Zn0Fe203 4.46 ZnS 2.94 Fe304 4.74 Fe2O3 4.91 FeS2 6.32 Ag2S 0.1 FeAs04"2H20 5.18 Bi203 0.59 Sb203 0.5 KAI3Si3010(01-)2 7.01 Al2Si203(OH)4 2.92 Ge g/ton 548 13 Date recue / Date received 2021-12-20 Table 2. Cu leaching results examples 1 to 7 Variable/Example Unit 1 2 3 4 5 6 7 H2SO4 g/L 150 250 150 250 250 150 250 concentration Solid content % w/w 5 5 15 15 15 20 20 Leaching time h 6 6 6 3 6 6 6 Cu leaching yield % 75.9 76.1 68.0 60 69.7 64.8 67.7 Examples 8 to 10 2,550 g of a 250 g/L H2SO4 solution were prepared, which were arranged in a 4 L autoclave, wherein the sludge previously subjected to a copper leaching process was added to a solid content of 15% w/w. The reactor was stirred at 300 rpm for 1 to 6 hours at 130 C. Once the reaction time is ended, the pulp was filtered in a Buchner system. Results are shown in Table 3. Table 3. Cu leaching results examples 8 to 10 Variable/Example Unit 8 9 10 Leaching time h 1 3 6 Cu leaching yield % 75.9 76.1 82.0 Mass loss % 35.0 41.0 42.0 Example 11 A refinery effluent dissolution was prepared (table 4) to which the H2SO4 concentration was adjusted to 250 g/L, which was arranged in a 5 L glass reactor, wherein 450 g of sludge previously subjected to a copper leaching process were added, in order to create a pulp with 15% w/w solids. The reactor was stirred at 300 rpm for 6 hours at 85 C. Once the reaction time is ended, the pulp was filtered in a Buchner system. Results showed a leaching yield of Cu of 72.0%, a leaching yield of Fe of 62.0%, a leaching yield of As of 71.5%, a leaching yield of Zn of 57.0% and a mass loss of 38.5%. Table 4. Refinery effluent composition Elements Unit Value H2SO4 g/L 35.73 Cu g/L 11.37 Fe g/L 0.10 14 Date recue / Date received 2021-12-20 Elements Unit Value As g/L 1.80 Bi g/L 0.00 Zn g/L 0.00 SO4 g/L 53.66 Sb g/L 0.04 Pb g/L 0.00 Al g/L 0.00 Ca g/L 0.51 Ag PPm 0.00 Ge PPm 0.00 Citric leaching Example 12 A solution was prepared with 40 L of distilled water to which it was added 14 kg of sodium citrate and the pH adjusted to 7.0 with a citric acid solution of 800 g/L. Once the reagents are dissolved 6 kg of leached sludge were added pursuant to example 3. The head sludge has a Pb content of 15.4%. Leaching was carried out at 20 C and stirred at 1,000 rpm for a 9 h period. A Pb leaching efficiency of 94% was obtained, thus obtaining a leached sludge reducing its mass in 24% with a Pb content of 1.19%. Examples 13 to 19 A solution was prepared with 2 L of distilled water with a concentration of between 323 and 368 g/L of sodium citrate at a pH between 5.3 and 8.8. The pH was adjusted with a citric acid solution of 800 g/L. Once reagents are dissolved the sludge processed under example 3 at a ratio of between 1.2 and 2.3 g of sodium citrate/g of sludge, is added. The head sludge has a Pb content of between 15.0 and 15.1%. Leaching was carried out between 30 and 60 C and stirred between 500 and 700 rpm for a period between 2 and 4 h. Results are shown in Table 5. Table 5. Citric leaching results examples 13 to 19 Variable/Example Unit 13 14 15 16 17 18 19 Sodium g:g 2.3 2.3 2.3 2.3 1.2 2.3 2.3 citrate:sludge ratio Sodium citrate g/L 350 350 350 350 323 368 368 concentration pH 8.8 8.8 8.8 5.3 5.6 5.3 5.3 Date recue / Date received 2021-12-20 Variable/Example Unit 13 14 15 16 17 18 19 Temperature C 30 40 60 40 40 40 40 Stirring rpm 500 500 500 500 500 500 500 Residence time H 4 2 2 4 4 4 4 Head Pb law % 15.1 15.1 15.1 15.1 15.1 15.0 15.0 Flock Pb law % 2.1 2.2 1.6 0.6 0.9 0.7 0.9 Pb leaching yield % 90 89 92 97 96 97 96 Mass loss % 24 25 24 26 28 32 29 Alkaline leaching Examples 20 to 28 A pulp was prepared with a sodium hydroxide solution with a concentration between 5.4 and 8.7% w/w and leached sludge subjected to copper and lead leaching consecutive processes with a solid content between 5.0 and 7.0 % w/w. The pulp was arranged in a 4 L autoclave and warmed to a temperature of between 100 and 140 C for between 1 and 6 hours at 600 rpm. Once the leaching time is fulfilled, the pulp was cooled and filtered in a Buchner system. Results are shown in Table 6. Table 6. Results examples 20 to 28 Variable/Example Unit 20 18 22 23 24 25 26 27 28 NaOH % w/w 5.6 5.6 5.6 5.6 5.6 7.2 5.4 8/ 5/ Concentration Solid content in % w/w 5.0 5.0 5.0 5.0 5.0 5.0 7.0 5.0 5.0 pulp Temperature C 100 140 120 120 130 130 140 140 130 Residence time h 3 3 1 6 3 3 3 6 3 Stirring rpm 600 600 600 600 600 600 600 600 900 Leaching yield Ge % 78.2 86.4 81.1 84.2 86.0 85.5 77.8 83.7 83.0 Si % 79.5 75.4 75.7 67.1 66.9 68.1 62.0 71.5 77.0 As % 90.9 94.1 92.2 93.1 94.3 93.3 95.0 95.5 90.0 K % 73.6 79.4 76.6 78.9 80.2 81.8 75.3 84.3 91.0 Examples 29 and 30 A pulp was prepared with 6,230 mL of water to which 420 g of sodium hydroxide and 350 g of leached sludge subjected to copper and lead leaching consecutive processes, were added, in order to obtain a concentration of 6.0% w/w of NaOH and 5.0% w/w of solids. The pulp was 16 Date recue / Date received 2021-12-20 arranged in a 10 L glass reactor and warmed at 90 C for between 1 and 6 hours and stirred at 900 rpm. Once the leaching time is fulfilled, the pulp was cooled and filtered in a Buchner system. Table 7. Results examples 29 and 30 Variable/Example Unit 29 30 Residence time h 1 6 Leaching yield Ge % 78.1 82.0 Si % 63.2 63.0 Ion exchange Examples 31 to 38 12,500 mL of a solution derived from alkaline leaching of sludge were taken, with concentrations of 28 to 34 mg/L of Ge and 7.2 to 8.6 g/L of Si, and were passed in an ion exchange column with 400 mL resin with a nitrogen atom group. The charge flow was 67 mL/min to 133 mL/min at a rate of 3.4 to 6.7 cm/min. The column was washed with 2000 mL water, with no germanium elution observed in any of the experiments. Germanium elution was performed with HCI at a rate of 99 g/L passing between 1 and 2 bed volumes. The elution flow was between 20 and 67 mL/min at a rate of between 1 and 3.4 cm/min. Lastly, the column was washed with 2000 mL water, with no Ge drag observed in any of the experiments. Results are shown in Table 8. Table 8. Results experiments 31 to 38 Example/Variable Unit 31 32 33 34 35 36 37 38 Resin IRA743 IRA67 WP-2 IRA743 IRA743 IRA743 IRA743 IRA743 Charge flow mL/min 67 67 67 100 133 67 67 67 Charge rate cm/min 3.4 3.4 3.4 5.1 6.7 3.4 3.4 3.4 Number of elution - 1.5 1.5 1.5 1 1.25 1 2 2 bed volumes Elution flow mL/min 20 20 20 20 20 20 40 67 Elution rate cm/min 1 1 1 1 1 1 2 3.4 Number of bed - 10 8 7 10 10 10 10 10 volumes for charge breaking point 17 Date recue / Date received 2021-12-20 Maximum mg/L 254 174 135 600 483 331 277 290 concentration of Ge Si charge with % 4 6 5 2 2 0.5 0.7 0.2 respect to the feed Silicon removal Examples 39 to 41 2,000 mL of the charge solution derived from the ion exchange column were taken with a concentration of 18.5 g/L Si and pH 3.7, to which it was added tetradecahydrate aluminum sulphate at a molar ratio Al/Si of 0.43 and 1.0. The mixture was stirred at 400 rpm and a temperature of 80 C for 60 minutes. Once the reaction was finished, the pulp was filtered and a Si removal efficiency of 74% was obtained, lowering the Si concentration to 2.8 g/L and that of Al to 130 mg/L with a pH of 13.4. Table 9. Results examples 39 to 41 Variable/Example Unit 39 40 41 Al/Si ratio h 0.43 0/0 1.00 Si precipitation yield 74 98 99 Si concentration g/L 2.8 041 0.12 following precipitation Al concentration g/L 0.13 1.00 3.5 following precipitation pH following 13.4 13.4 12.5 precipitation Examples 42 to 45 4,200 g of a IX (ion exchange) discharge solution were taken, with 17.4 g/L Si in a 5 L reactor at a temperature within the range of 20 to 70 C, to which calcium hydroxide was added at a molar ratio within the range of 0.9 to 1.1 mol Ca/mol Si, with continuous stirring at 300 rpm for 60 minutes. Once the reaction is concluded, the pulp was filtered in filter paper No.42. Table 10. Results examples 42 to 45 Variable/Example Unit 42 43 44 45 Ca/Si ratio h 0.9 11 11 11 Temperature C 70 20 50 70 18 Date recue / Date received 2021-12-20 Variable/Example Unit 42 43 44 45 Si precipitation yield % 82 70 83 95 Germanium distillation Example 46 18,000 mL of a solution with 454 mg/L Ge, 1,039 mg/L Pb, 294 mg/L Al, 7 mg/L As and 150 g/L HCI were taken as an output solution of the ion exchange column elution. The solution was disposed in a distillation balloon of 20 L and heated to 108 C. Once the bulb temperature reached 108 C, the distillate solution output was observed, which was kept in fractions between 300 and 1,200 mL. The evaporated solution was condensed in a coil through which cold water was circulated at 5 C, and received in a jacketed collecting cup through which water circulated at 5 C. A total of 100% Ge was collected in the distillate, obtaining fractions with up to 1,960 mg/L Ge. 0.02% of the Pb present in the solution passed to the distillate, whereas 0.19 and 50% of Al and As, respectively, were dragged by the distillate. Example 47 14,000 mL of a solution with 1,060 mg/L Ge and 100 g/L HCI were taken as germanium distillation solution. The solution was disposed in a distillation balloon of 20 L and heated to 108 C. Once the bulb temperature reached 108 C, the distillate solution output was observed, which was kept in fractions of 500 mL. The evaporated solution was condensed in a coil through which cold water was circulated at 5 C, and received in a jacketed collecting cup through which water circulated at 5 C. A total of 100% Ge was collected in the distillate, obtaining fractions with up to 4,330 mg/L Ge. Example 48 16,000 mL of a solution with 2,630 mg/L Ge and 117 g/L HCI were taken as germanium distillation solution. The solution was disposed in a distillation balloon of 20 L and heated to 108 C. Once the bulb temperature reached 108 C, the distillate solution output was observed, which was kept in fractions of 1.000 mL. The evaporated solution was condensed in a coil through which cold water was circulated at 5 C, and received in a jacketed collecting cup through which water circulated at 5 C. A total of 100% Ge was collected in the distillate, obtaining fractions with up to 15,000 mg/L Ge. Example 49 .. 16,000 mL of a solution with 10,400 mg/L Ge and 150 g/L HCI were taken as germanium distillation solution. The solution was disposed in a distillation balloon of 20 L and heated to 108 C. Once the bulb temperature reached 108 C, the distillate solution output was observed, 19 Date recue / Date received 2021-12-20 which was kept in fractions of 1.000 mL. The evaporated solution was condensed in a coil through which cold water was circulated at 5 C, and received in a jacketed collecting cup through which water circulated at 5 C. A total of 100% Ge was collected in the distillate, obtaining fractions with up to 25,000 mg/L Ge. Germanium hydrolysis Examples 50 to 57 250 mL of a germanium solution with a concentration within the range of 4.1 to 24.8 g/L Ge and an HCI concentration between 54 and 134 g/L were taken, which were disposed in a jacketed 500 mL reactor, through which 5,000 mL of water were circulated in a 1% volume mixture of ethylene glycol and cooled by a cooling equipment at 1 C. The solution was mechanically stirred at 250 rpm for 5 h at a temperature between 2 and 3 C. At the end of the process the solution was filtered in filter paper of 0.45 pm. Table 11. Results examples 50 to 57 Variable/Example Unit 50 51 52 53 54 55 56 57 Start Ge g/L 4.1 4.1 83 83 16.5 16.5 24.8 24.8 HCI g/L 54 134 54 134 54 134 54 134 Precipitate g s/p s/p s/p 1.1 2/ 4.6 4.5 7.8 Ge 69 66 66 63 68 Date recue / Date received 2021-12-20