ES3041049A1 - PROCEDURE FOR THE HYDROMETALLURGICAL PROCESSING OF MINERALS CONTAINING SULFIDES OF Cu, Zn AND/OR Pb (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Hydrometallurgical beneficiation process for ores containing copper, zinc, and/or lead sulfides. This process is suitable for the hydrometallurgical utilization of ores containing copper, zinc, and/or lead sulfides, particularly those from the Iberian Pyrite Belt or similar regions. It allows for the comprehensive recovery of copper, zinc, and lead sulfides through a combination of stages for the selective recovery of copper, zinc, lead, and precious metals (primarily silver and gold, if present). This recovery is achieved by using a ferric compound, preferably ferric sulfate, in one or more of these leaching stages. Oxygen concentration is controlled, and no additional oxygen aeration or bubbling is introduced to prevent the oxidation of sulfur to sulfate in the leaching medium. The process is also carried out in the presence of a carbon adsorbent. The procedure of the invention minimizes the consumption of neutralizing chemical compounds and the waste generated, since the pH remains stable during leaching with Fe3 by controlling the atmosphere in contact with the leaching medium. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Procedure for the hydrometallurgical beneficiation of minerals containing copper, zinc and/or lead sulfides

Field of invention

The present invention falls within the field of extractive metallurgy, sustainability, and the circular economy. Its main objective is a process for the hydrometallurgical beneficiation of complex minerals containing metal sulfides such as zinc, copper, and lead, as well as precious metals, primarily silver (Ag), which is particularly applicable to minerals from the Iberian Pyrite Belt. The invention's process consists of a multi-stage combination that includes, among other things, a Zn and copper leaching stage under specific conditions with limited oxygen. This allows for pH control and reduces the consumption of neutralizing chemical compounds and waste generation. The process also allows for the recovery of sulfur or sulfur compounds generated during the leaching process, further minimizing waste. The leaching conditions also prevent pyrite oxidation.

This invention aims to provide an efficient solution to the mining and metallurgical treatment of minerals preferably located in the metallotect known as the Iberian Pyrite Belt, one of the largest European reserves of base metals (Zn, Cu and Pb) and precious metals (mainly Ag), and by extension to all deposits with similar characteristics.

Background of the invention

The Iberian Pyrite Belt is a vast area of submarine volcanism, 250 km long (east-west) and 70 km wide (north-south), exploited since the Tartessian period. It currently contains economically important deposits such as Aznalcóllar, Minas de Rio Tinto, Almagrera, Masa Valverde, Aguas Teñidas, San Telmo, and Lomero Poyatos in Spain, and Neves Corvo and Ajustrel, among others, in Portugal. Despite its enormous mineral resources (more than 1 billion tons of Cu-Zn-Pb-Au-Ag metallic sulfides), the depletion of the oxidation zone, which is easier to leach and therefore treat hydrometallurgically, the low grades of the deposits, and the complexity of processing complex sulfides mean that many deposits are currently unviable. The problems associated with the exploitation of metals from the Iberian Pyrite Belt have remained unresolved for decades. The present invention represents a significant advance due to the following considerations:

The traditional method for extracting these low-grade ores from the Iberian Pyrite Belt is differential flotation to produce individual concentrates that can be processed using traditional metallurgical methods for copper, zinc, and lead. This differential flotation method has significant limitations in terms of metal recovery and the grade obtainable in the individual copper, zinc, and lead concentrates. Furthermore, the differential concentrates of each metal carry impurities of the other metals, which act as a penalty, reducing their economic value. This is because the constituent mineral species are frequently finely mixed. All of this results in the current economic impossibility of exploiting certain deposits in the Iberian Pyrite Belt, as well as a reduction in the potential economic benefits that could be obtained.

An alternative to differential flotation would be the global flotation process, which was carried out at the time by the state-owned company Almagrera S.A., establishing a grinding to the liberation size of the pyrite, normally between 35 and 55 microns, followed by an aeration stage to oxidize it, thus depressing its floatability, followed by an activation conditioning with copper sulfate, regulation of pH above 10.5 and a collector such as SIBX, dithiophosphinates or thiocarbamates, among others, as shown in Figure 1. This method is optimized in each deposit.

Extracting metals from these global concentrates is difficult and complex, requiring the efficient and viable separation and recovery of Zn, Cu, and Pb in an integrated process. Obtaining high-value refined metals from these polymetallic raw materials necessitates an efficient combination of several stages, while also minimizing waste generation. To date, various processes have been developed for the metallurgical exploitation of global concentrates from the Iberian Pyrite Belt, but none have provided a satisfactory solution for the sustainable exploitation of these deposits. These processes include the following:

1. The COMPREX process consists of the pressure digestion of coarse copper, lead, and zinc concentrates in a sulfuric acid medium. The fundamental problem with this process is that all the sulfur is transformed into sulfate and sulfuric acid, which must be neutralized with CaO or Ca(OH)2, generating an environmental problem related to land use and costs that are impossible to manage. Therefore, the process was abandoned at the time.

2. - Hydrochloric acid leaching processes (Cuzclor processes: Cuprex, Zinclor, or Ledclor) The fundamental problem common to these processes is the high cost of hydrochloric acid, equipment corrosion, and the disposal of the generated waste, composed of chlorinated salts, almost all of which are soluble. Furthermore, leaching regeneration requires the use of membrane or diaphragm electrolysis, with the associated technical difficulties. The application of these processes in the Iberian Pyrite Belt has not yet been implemented.

3. Processes based on ferric leaching in sulfuric acid with leaching agent regeneration via various methods, including bio-oxidation with mesophilic or thermophilic bacteria (BRISA process), or other types of oxidation, and the use of catalysts, generally silver chloride. In general, the leaching kinetics of Zn from sulfides are very rapid and acceptable, as are those of catalyzed Cu. Pb remains in the residue, from which it can be recovered. The main problem lies in the fact that it requires the recovery of Ag, so its use is only justified if the ores contain a sufficient quantity of precious metals.

More recently, several patents have been developed that aim to advance the solution for utilizing these global concentrates.

Patent document ES0414173, "High-Temperature Pressure Leaching Process in Aqueous Medium for Complex Sulfides," refers to the hydrometallurgical treatment of complex sulfides of iron and other non-ferrous metals, and more specifically, to the process of extracting copper (Cu) and zinc (Zn) from these sulfides by pressure oxidation (5.0–18 kg/cm²/g) in an aqueous medium at high temperature (between 175°C and 220°C). The preferred gas used is oxygen, although air and oxygen-enriched air can also be employed. The described method allows for the direct treatment of minerals with low concentrations of Cu and Zn, although it is primarily applied to total flotation concentrates. The procedure can be used to process Cu and Zn concentrates composed of various mineralogical species such as chalcopyrite, covellite, bornite, chalcocite, sphalerite, etc.

Patent document ES0476055A1 describes the extraction of Cu, Pb, Zn, Ag and Au from complex sulfide minerals by a process comprising a pressure reactor with oxygen, operating at 200 °C, where all metal sulfides are oxidized to sulfates, subsequently recovering the various metals separately.

Patent document ES2137871 describes a hydrometallurgical process for the beneficiation of polymetallic pyrite minerals. This process relates to the treatment of polymetallic sulfide minerals of iron and other non-ferrous metals, and specifically, to pyrite-based minerals containing minor amounts of Cu, Zn, Pb, and Ag sulfides, such as the complex pyrites abundant in the Iberian Pyrite Belt. More specifically, it relates to the extraction of Cu, Zn, Pb, and Ag from these sulfides using a hydrometallurgical process that combines oxidation operations in an aqueous medium with oxygen at pressure and high temperature, selective solvent extraction operations for Cu and Zn, cementation operations for the Pb and Ag solubilized in the leaching of the ferrous residue with brine, and membrane separation operations for minimizing and recycling brine and wastewater.

Patent document ES2794298 “Metal extraction process from polymetallic sulfide ores or concentrates” describes the hydrometallurgical metal extraction process from polymetallic sulfide ores or concentrates containing several base metals and precious metals, comprising at least Cu as chalcopyrite, Zn, Pb and Ag, and comprising a first stage of atmospheric pressure leaching in a sulfate medium with oxygen and in the presence of silver in an amount suitable to catalyze the leaching of Cu and Zn, and a second stage of atmospheric pressure leaching in a chloride medium, where Pb and Ag are leached; subsequently, these four metals are recovered separately as high-value products.

Patent document ES2674440A1 describes a hydrometallurgical plant for the treatment of complex sulfides, specifically a process for extracting copper (Cu) and zinc (Zn) from these sulfides by leaching at atmospheric pressure in an aqueous medium and operating at a temperature below 100°C. The described procedure allows for the direct treatment of ore with low Cu and Zn grades, as well as the treatment of aggregate flotation concentrates. Leaching is carried out in one stage, using ferric sulfate as the oxidizing agent for the sulfides. This sulfate is generated in an oxidation-precipitation stage of the leaching solution. To promote oxidation of the ferrous ions generated during the leaching of Cu and Zn with atmospheric air instead of oxygen, the solution is neutralized to pH 4.5–5.0 with ammonia.

Patent document ES2794298 describes a process for extracting metals from polymetallic sulfide minerals or concentrates comprising at least Cu, Zn, Pb and Ag, comprising a first stage of atmospheric leaching in sulfate medium in the presence of recycled silver to extract Cu and Zn and a second stage of atmospheric leaching in chloride medium to extract Pb and Ag.

Patent document CL 2015003189 describes a bioleaching and solvent extraction process with selective recovery of Cu and Zn from polymetallic sulfide concentrates, comprising a ferric ion reduction stage and an arsenic control stage. In this process, the bioleaching and ferric ion reduction stage includes the following steps: a) conditioning a pulp of polymetallic sulfide concentrates; b) bioleaching the pulp of polymetallic sulfide concentrates; c) separation of solids from the pulp from the bioleaching stage and, d) ferric ion reduction transformation while the Cu and Zn solvent extraction stage includes the stages of a) solvent extraction and copper electrolysis b) As control and, c) solvent extraction and Zn electrolysis where the bioleaching stage is carried out using a plurality of stirred tank type bioreactors that have a system for air injection and diffusion, which allows handling a pulp density in solids greater than 15, high efficiency in air distribution, in addition to recovering the water that evaporates during the process.

Patent document ES2017554 describes a procedure for the comprehensive utilization of sulfide minerals. The ore, conditioned to a suitable particle size, is subjected to a wet treatment with an oxidizing agent, preferably ferric chloride, resulting in two streams: a liquid stream containing dissolved non-ferrous metals (Cu, Zn, and Pb) and precious metals in such a way that they can be recovered, simultaneously regenerating the leaching solution, which is suitable for recirculation; and a solid stream that is subjected, in a closed circuit in an inert atmosphere and with indirect heat input, to a fluidized bed distillation at a moderate temperature to distill the sulfur along with the other volatile elements, leaving a residue that is subjected to a third stage of acid leaching in which gaseous hydrogen sulfide is produced, partially usable in the Claus process itself, and a lye that contains pyritic iron in the form of ferrous salt and, once purified, is suitable for regenerating the leaching agent and producing high-quality iron oxide.

The regeneration of the oxidant can be carried out simultaneously with the leaching by incorporating the chlorine released in the metal recovery stages by electrolysis.

In these processes, the use of oxygen at atmospheric pressure or higher pressures, as well as the high amount of easily leachable ZnS, leads to a complete oxidation of sulfides to sulfates, generating a significant decrease in pH, whose neutralization with CaO or Ca(OH)2 involves a significant economic cost and also leads to the production of a huge amount of gypsum waste.

Among the copper minerals present in the global concentrates of the Iberian Pyrite Belt, chalcopyrite stands out. It is a mineral resistant to leaching in acidic media (sulfuric acid, alone or in combination with hydrochloric or nitric acid, or associated with bioleaching), which is the conventional hydrometallurgical process for extracting copper from oxidized ores. In the case of lime

During leaching, different compounds are formed, depending on the conditions of the leaching process, which passivate the surface of the chalcopyrite, slowing down and even stopping the leaching reaction, resulting in very low copper extraction.

In this regard, US patent 8,795,612 B2 describes a hydrometallurgical method for recovering copper from a chalcopyrite concentrate by chemical leaching, using pyrite and silver as catalysts. The catalytic properties of pyrite in the chalcopyrite leaching process are significantly enhanced by pretreating the pyrite with silver ions. Particulate pyrite is exposed to a solution containing silver ions to form silver-treated pyrite. The lime concentrate

The concentrate is mixed with a leaching solution made from sulfuric acid. Copper is leached from the concentrate in the leaching solution in the presence of oxygen gas, under conditions where the pyrite is substantially unoxidized. The leached copper is recovered from the solution by conventional methods. The spent silver-treated pyrite is recycled back into the process.

Patent document JP0006798817B9 proposes a method for leaching and recovering Cu from chalcopyrite that consists of mixing chalcopyrite with a carbon material in an aqueous solution of sulfuric acid; and heating and stirring the aqueous solution of sulfuric acid in the co-presence of oxygen.

Patent document JP 2015130451 describes the process of leaching copper from chalcopyrite, which includes the steps of mixing chalcopyrite with manganese oxide and carbon material, and immersing the resulting mixture in a sulfuric acid solution.

US patent document 2012/0279357 describes the process of leaching Cu from a copper sulfide concentrate comprising copper-arsenic or copper-antimony sulfosalts using different carbons, including activated carbon as a catalyst and O2 to regenerate the leaching agent and facilitate the oxidation of the copper concentrates.

Finally, the publications "Catalytic Activity of Carbon Materials in the Oxidation of Minerals" by Aura Alejandra Burbano et al., in Catalysts 2022, 12(8), 918, "Hydrometallurgical Recovery of Cu and Zn from a Complex Sulfide Mineral by Fe3+/H2SO4 Leaching in the Presence of Carbon-Based Materials", by María Luisa Álvarez et al., in Metals 2021, 11(2), 286 and "Biomass-derived activated carbon as catalyst in the leaching of metals from a copper sulfide concentrate" by A. Méndez et al., in Minerals Engineering, Vol. 183, June 15, 2022, page 107594, show how the use of different carbonaceous materials can increase the recovery of Cu and Zn from differential chalcopyrite concentrates from the Iberian Pyrite Belt.

Brief description of the figures

Figure 1: Standard scheme of the overall flotation process for complex metal sulfides. Figure 2: Flow diagram of the process of the invention for the comprehensive beneficiation of complex sulfides from the Iberian Pyrite Belt.

Figure 3. Extraction (%) of Cu and Zn at different times (1, 2, 5 and 6 hours) according to the procedure of the invention.

Summary of the invention

Therefore, there is still a need to provide new procedures for the hydrometallurgical beneficiation of minerals containing Cu, Zn and/or Pb sulfides that overcome the disadvantages of the procedures known in the state of the art.

Thus, in one main aspect, the invention relates to a process for the hydrometallurgical beneficiation of minerals containing Cu, Zn and/or Pb sulfides such as those found in the Iberian Pyrite Belt, comprising the following stages:

a) grinding the ore to a size smaller than the liberation size of pyrite, b) flotation of the Cu, Zn and/or Pb sulfides with separation of the pyrite by flotation depression by pre-aeration,

c) regrinding of the Cu, Zn and/or Pb sulfide concentrate from the previous stage to a size smaller than the liberation size thereof,

d) Leaching of the concentrate from the previous stage with a sulfuric acid solution at pH between 0.6 and 1 with ferric ion in excess with respect to the total Zn and Cu content in the presence of a carbon adsorbent, with an O2 concentration in the leaching medium that is at most that of the equilibrium of O2(g) at the leaching temperature and without aeration or bubbling of O2, at a temperature between 60°C and 100°C, in a closed container and with stirring of the mixture,

e) size separation of the carbon adsorbent, the pyrite-rich residue, the Pb sulfate and any precious metals present, obtaining a liquid phase rich in Fe2+/Fe3+,

f) extraction with organic solvents or ion exchange of Zn and Cu from the liquid phase of the previous stage,

g) oxidation of the Fe2+ from the liquid phase resulting from the previous stage to Fe3+ and separation of the excess Fe3+ for regeneration of the leaching agent,

h) Thermal treatment of the concentrate resulting from the previous stage for the recovery of sulfur at a temperature above the melting point of sulfur, and at a temperature above the boiling point of the impurities for their extraction, and regeneration of the carbon adsorbent by physical or chemical oxidation for its subsequent reuse,

i) treatment of the solid mineral residue resulting from the previous stage with a metal complexing compound containing Au and/or Ag for the selective recovery of precious metals, if present, and the separation of pyrite, and

j) separation of Pb sulfate from the final residue by physical methods.

The present invention is based on utilizing coarse concentrates of Zn, Cu, and Pb, minimizing the losses that occur in differential flotation to obtain differentiated concentrates of Cu, Pb, and Zn, while also reducing the fine grinding costs required for differential flotation. As mentioned, currently the only concentrates that can be commercially sold are the differentiated concentrates of Cu, Zn, and Pb. However, considering metal recovery, the reduced selling price due to impurities, and the grinding process, coarse flotation is much more advantageous. Therefore, the present invention, by starting with coarse concentrates, would achieve a significantly better economic recovery of the mineral resources characteristic of the Iberian Pyrite Belt.

Detailed description of the invention

The overall concentrates from the Iberian Pyrite Belt typically have a pyrite content between 15% and 30%, with a sum of non-ferrous metal grades ranging from 30% to 50%. Zinc (Zn) is the predominant metal compared to copper (Cu), a ratio that varies depending on the deposit and flotation process, but can exceed 15:1 by weight. Furthermore, these overall concentrates often contain silver (Ag) derived from the metal content of the original deposits, which is usually found at concentrations of 70 g/t.

The process of the present invention allows for the comprehensive utilization of copper, zinc, and lead sulfides, such as those found in the Iberian Pyrite Belt, through the combination of several stages for the selective recovery of copper, zinc, lead, and precious metals (primarily silver and gold, if present). This is achieved by using a ferric compound, preferably ferric sulfate, in one or more of these leaching stages. The oxygen concentration is controlled, reaching a maximum of the equilibrium concentration of oxygen(s) at the leaching temperature. No additional aeration or bubbling of oxygen is used to prevent the oxidation of sulfur to sulfate in the leaching medium, which would generate protons and acidify the leaching liquor. The process is also carried out in the presence of a carbon adsorbent, preferably activated carbon with a high adsorption capacity for hydrogen sulfide (H₂S) and other sulfur compounds. The invention's procedure minimizes the consumption of neutralizing chemical compounds and the waste generated, since the pH remains stable during leaching with Fe3+ without aeration or O2 bubbling (controlling the atmosphere in contact with the leaching medium).

The reactions that take place in this leaching stage are as follows:

ZnS Fe2(SO4)3 = ZnSO4 2 FeSO4 S°

CuFeS2 2 Fe2(SO4)3 = CuSO4 5 FeSO4 2 S°

PbS Fe2(SO4)3 = PbSO4(s) 2 FeSO4 S°

Ag2S Fe2(SO4)3 = Ag2SO4(s) 2 FeSO4 S°

The reaction that is prevented, due to the limitation of O2, is the following:

2S°+ 3O2 4H2O= 2 SO42- 8H+

The main new features of this method are:

a) the hydrometallurgical treatment of global concentrates, ideally from the Iberian Pyrite Belt, instead of individual Zn or Cu concentrates.

b) During the leaching stage, a carbon adsorbent is combined with an excess of ferric ion as an oxidizing agent in a sulfuric acid medium, without aeration or O2 supply. This prevents the over-oxidation of elemental sulfur to sulfate and removes sulfur from the medium through the presence of the carbon adsorbent, thus avoiding acidification of the leaching medium. The initial pH of the medium must be below 1.0 to prevent iron precipitation due to the high ferric concentrations used. The first stage of the process described herein yields a Zn/Cu-rich leaching liquor with a pH between 0.6 and 1.0, depending on the initial leaching pH, elemental sulfur, and a residue rich in pyrite, lead sulfate, and any precious metals present, which is treated in a subsequent stage.

In preferred embodiments, the present invention provides a process for the beneficiation of metal sulfides of Cu, Zn, and Pb comprising the following steps:

Stage 1. Grinding of ore from the Iberian Pyrite Belt or similar to a size smaller than the liberation size of pyrite, i.e., around 35-55 µm, and flotation in aqueous medium of the overall concentrate of Cu, Zn, and Pb sulfides, with prior aeration to depress the pyrite and adjustment of pH and reagents according to the ore composition. The aeration stage aims to oxidize the pyrite, thus depressing its floatability. In this way, the Cu, Pb, and Zn sulfides float, leaving pyrite and non-sulfide minerals in the flotation residue.

Stage 2. Conditioning of the overall mineral concentrate of Cu, Zn and Pb sulfides by regrinding to the liberation size of the same, normally less than 20-30 pm prior to the leaching stage, which will favor the kinetics of the subsequent leaching processes.

Stage 3. Treatment of the overall concentrate at a temperature between 60 and 100°C, preferably between 80 and 90°C, with a solution of H2SO4 with Fe3+ as an oxidizing agent, preferably in the form of ferric sulfate, added in a molar ratio preferably greater than 2 with respect to the total content of Zn and Cu, with an O2 concentration in the medium that will be at most that of the equilibrium of O2(g) at the leaching temperature, without aeration or bubbling of O2 or air to avoid over-oxidation of sulfur to sulfuric acid, and with pH between 0.6 and 1.0 to avoid precipitation of iron, in a closed container, with stirring of the mixture for a time preferably between approximately 5 and 10 hours.

Step 4. Size separation of the carbon adsorbent and the residue rich in pyrite, Pb sulfate and precious metals (Au and Ag if present).

Step 5. Extraction with organic solvents or ion exchange of Zn and Cu from the aqueous phase rich in Fe2+/Fe3+ for the production of Zn and Cu metal.

Step 6. Oxidation of Fe2+ to Fe3+ from the liquid phase with any oxidizing agent, after the extraction of Zn and Cu, for the regeneration of the leaching agent

Step 7. Heat treatment of the carbon adsorbent, which has retained sulfur as well as impurities, at a temperature above the melting point of sulfur for sulfur recovery, and at a temperature above the boiling point of the impurities for their extraction, followed by regeneration of the carbon adsorbent by physical or chemical oxidation for reuse.

Stage 8. Treatment of the solid mineral residue rich in pyrite, Pb sulfate and precious metals (Ag and Au if present, for the recovery of Au and Ag), with any compound that forms metal complexes with Au and/or Ag such as glycine, cyanide, urea, thiourea among others.

Step 9. Separation of Pb sulfate from the final pyrite-rich residue by physical methods, such as aqueous flotation with foams or by densiometric separation or by valorization or disposal of the pyrite under environmentally acceptable conditions.

The method of the invention starts with a combined concentrate of Zn, Cu, and Pb and combines several stages to achieve greater selectivity in the extraction processes for Zn, Cu, and Pb (and Ag and Au, if present), thereby reducing subsequent purification costs. Furthermore, it reduces the consumption of chemical compounds needed to control the acidic pH that would be generated during the traditional leaching process in the presence of O2, as well as the waste generated for neutralizing the leaching liquor. The proposed method achieves Cu and Zn recoveries exceeding 80-90% in 58 hours and recovers the sulfur or sulfur compounds generated during the leaching process, minimizing their transformation into sulfates. In addition, it prevents the oxidation of pyrite present in the combined concentrate. Therefore, this method allows for the sustainable exploitation of metallic sulfides and is ideally applicable to the minerals of the Iberian Pyrite Belt. The amount of carbon adsorbent required must be optimized based on its composition (primarily the oxygenated groups) and the overall metal complex (especially the sphalerite and chalcopyrite content). Zn and Cu leaching is carried out with excess ferric sulfate, so the pH must be below 1.0 to prevent iron precipitation. Recovering the sulfur fixed on the activated carbon could be another source of revenue in the future.

Experimental Examples

Example 1

Leaching conditions: H2SO4 solution with initial pH=0.8, 5g/L of Fe3+, in the presence of a carbonaceous adsorbent (total concentrate/adsorbent weight ratio 1/0.25, temperature 90°C, leaching time 6 hours). Composition of the concentrate obtained: Zn 13.84%; Cu 6.8%; Pb 2.96%; Ag 136 g/kg.

Example 2

Leaching conditions: H2SO4 solution with initial pH=0.89, 10g/L of Fe3+, in the presence of a carbonaceous adsorbent (total concentrate/adsorbent weight ratio 1/0.25, temperature 90°C, leaching time 5 hours). Composition of the concentrate obtained: Zn 12.02%; Cu 3.5%; Pb 1.96%; Ag 87 g/kg.

Therefore, the present invention represents an efficient process that can solve the problems of exploiting the deposits of the Iberian Pyrite Belt, and in general all deposits with similar characteristics, worldwide.

Claims (11)

1. Procedure for the hydrometallurgical beneficiation of minerals containing Cu, Zn and/or Pb sulfides, comprising the following stages: a) grinding the ore to a size smaller than the liberation size of pyrite, b) flotation of the Cu, Zn and/or Pb sulfides with separation of the pyrite by flotation depression by pre-aeration, c) regrinding of the Cu, Zn and/or Pb sulfide concentrate from the previous stage to a size smaller than the liberation size thereof, d) Leaching of the concentrate from the previous stage with a sulfuric acid solution at pH between 0.6 and 1 with ferric ion in excess with respect to the total Zn and Cu content in the presence of a carbon adsorbent, with an O2 concentration in the leaching medium that is at most that of the equilibrium of O2(g) at the leaching temperature and without aeration or bubbling of O2, at a temperature between 60°C and 100°C, in a closed container and with stirring of the mixture, e) size separation of the carbon adsorbent, the pyrite-rich residue, the Pb sulfate and any precious metals present, obtaining a liquid phase rich in Fe2+/Fe3+, f) extraction with organic solvents or ion exchange of Zn and Cu from the liquid phase of the previous stage, g) oxidation of the Fe2+ in the liquid phase resulting from the previous stage to Fe3+ and separation of the excess Fe3+ for regeneration of the leaching agent, h) heat treatment of the carbon adsorbent, which has retained sulfur as well as impurities, at a temperature above the melting point of sulfur for sulfur recovery, and at a temperature above the boiling point of the impurities for their extraction, followed by regeneration of the carbon adsorbent by physical or chemical oxidation for reuse, i) treatment of the solid mineral residue resulting from the previous stage with a metal complexing compound containing Au and/or Ag for the selective recovery of precious metals, if present, and the separation of pyrite, and j) separation of Pb sulfate from the final residue by physical methods. 2. Process according to claim 1 wherein, in step a), the release size of the pyrite is a size less than 55 pm. 3. Process according to claim 1 or 2 wherein, in step c), the liberation size of the Cu, Zn and/or Pb sulfides is a size less than 30 pm. 4. A process according to any of the preceding claims wherein, in step d), the ferric ion is provided in the form of ferric sulfate. 5. Process according to claim 4, wherein the molar ratio of ferric sulfate to the total content of Zn and Cu is greater than 2. 6. A process according to any of the preceding claims wherein, in step d), the carbon adsorbent is activated carbon with a high adsorption capacity of H2S and other sulfur compounds. 7. A process according to any of the preceding claims wherein, in step d), the pH is between 0.8 and 0.9. 8. A process according to any of the preceding claims wherein, in step e), the precious metals are Au and/or Ag. 9. A process according to any of the preceding claims wherein, in step i), the metal complexing compounds with Au and/or Ag are selected from glycine, cyanide, urea, and/or thiourea, alone or in any combination thereof. 10. A process according to any of the preceding claims wherein, after step j), the pyrite is dumped or recovered. 11. A process according to any of the preceding claims wherein the minerals containing Cu, Zn and/or Pb sulfides are obtained from the Iberian Pyrite Belt or from other similar sources.