MySx / ZSH MIXTURE AS A SULFIDIZING AGENT AND PROCESS USING IT TO RECOVER ONE OR MORE METALLIC AND / OR POLYMETALLIC ORES FROM THE GANGUE

Abstract

The description refers to a sulfidizing agent obtainable by mixing M y S x and ZSH in a weight ratio of 90:10 to 10:90, where M is selected from Li + , Na + , K + , Rb + , Cs + , NH + 4, Mg 2+ or Ca 2+ , and is 1 or 2, x is from 1.1 to 5, and Z is selected independently of Li + , Na + , K + , Rb + , Cs + and NH + 4, and a process for using the sulfidizing agent in the recovery of one or more metallic ores and / or polymetallic minerals from the gangue.

Description

MySx / ZSH MIXTURE AS A SULFIDIZING AGENT AND PROCESS USING IT TO RECOVER ONE OR MORE METAL ORES AND / OR POLYMETALLIC GANGUE MINERALS This invention relates to a mixture of MySx / ZSH as a sulfidizing agent and a process for using the same in the recovery of one or more metallic ores and / or polymetallic minerals from gangue. Background Currently, there are two main metal extraction processes used in mining to recover metallic ores and / or polymetallic minerals from gangue. If the ore is in its oxidized form (i.e., minerals formed by the bonding of metals and metalloids with oxygen), recovery is generally through leaching, while froth flotation is generally used for metallic sulfides. The leaching process extracts a species of interest from a mineral sample using reagents that dissolve or transform the species into soluble salts. Therefore, in leaching, the valuable species are recovered from a liquid phase, which corresponds to the substance or a salt of it in aqueous solution. However, leaching processes require high operating acidity and, in some cases, produce toxic waste effluents. Leaching processes can also suffer from reduced efficiency due to the low operating temperatures, which dramatically affect the rates of chemical reactions. Froth flotation separation is based on the ability of air bubbles to selectively bind to particles that have been previously made hydrophobic. The particle-bubble combinations then rise to the froth phase from which they are discharged from the flotation cell, while the hydrophilic particles remain in the cell. The hydrophobicity of the particles, in turn, is induced by special chemicals called collectors. Page 1 of 35 In 1,606,582 of the 36 forward flotation systems, the economically valuable minerals are made hydrophobic by the collector. Similarly, in reverse flotation systems, the collector makes the waste mineral particles hydrophobic. The efficiency of the separation process is quantified in terms of recovery and purity. Recovery refers to the percentage of valuable product contained in the ore that is removed in the concentrate stream after flotation. Purity refers to the percentage of economically valuable product in the concentrate after flotation. A higher recovery or purity value indicates a more efficient flotation system. In addition to collectors, frothing agents (or foaming agents) can also be used in a froth flotation process. Frothing agents have three main functions: they aid in the formation and preservation of small bubbles, reduce the rate at which bubbles rise, and promote froth formation. In this respect, they play a completely different role from collectors, which generally need to impart lipophilicity to the minerals to make them float. Surfactants achieve this by adsorbing onto mineral surfaces, making them water-repellent. This reduces the stability of the hydrated layer separating the mineral from the air bubble to such a degree that particle adhesion to the bubble can occur.For this reason, foaming agents are characterized by the need to have a much lower log P (partition coefficient) value than the collector components, or to put it another way, foaming agents are generally much more hydrophilic than collectors. A problem many mines face is that they have a combination of sulfide and oxide ores. Therefore, they must decide whether to process the mixture through flotation, which increases oxide losses, or through leaching, where some of the sulfide content is lost. In copper mining, for example, oxide and sulfide ores are found mixed in many different proportions. The most common oxide or copper minerals are carbonates (malachite and azurite), sulfates (brochantite and antlerite), and oxychlorides (atacamite and chrysocolla hydrate silicate), while copper minerals Page 2 of 35 1606582 of 36 most common sulfides are chalcopyrite (CuFeSi), bornite (CusFeS4), chalcocite (Cu2S), covellite (CuS) and enargite (CusAsS4). It is traditional for copper mines to recover metallic ores and / or polymetallic minerals from gangue using froth flotation. In some cases, "sulfidizing" is used as an important tool to enhance the recovery of some of the oxides. Here, a sulfidizing agent, such as sodium hydrogen sulfide (NaSH), is added during froth flotation or just before the ground mineral pulp is fed into the flotation cells. This produces a metal-sulfide layer on an oxidized mineral ore surface, allowing sulfide collectors to adhere to the mineral surface and make the mineral particles hydrophobic so they can be recovered by conventional sulfide flotation (i.e., straight flotation). The advantage of this process is that it allows the recovery of significant quantities of metal that would otherwise be lost, without the need to invest in new plants and equipment, since the only difference with traditional flotation is that the sulfidizing agent is added to the process. In the case of sodium hydrogen sulfide, doses exceeding 100 g / ton of ore are necessary to achieve good results. However, overdosing on sodium hydrogen sulfide results in an adverse depressant effect, causing the metal to re-float and be lost in the tailings. Additionally, the use of sodium hydrogen sulfide is associated with handling problems due to potential H₂S emissions. Consequently, there is a need to provide sulfidizing agents and improved processes that have good recovery yields and cause depressant effects and reduced H2S emissions. Page 3 of 35 1606582 of 36 Summary of the description In a first aspect, the invention provides a sulfidizing agent obtainable by mixing MySx and ZSH in a weight ratio of 90:10 to 10:90, wherein M is selected from Li+, Na+, K+, Rb+, Cs+, NH4+, Mg2+ or Ca2+, and is 1 or 2, x is from 1.1 to 5, and Z is selected independently from Li+, Na+, K+, Rb+, Cs+ and NH4+. Advantageously, sulfidizing agents prepared by mixing MySx and ZSH according to the first aspect of the invention have been found to provide recovery yields superior to or similar to NaSH, while exhibiting a very low depressant effect and significantly reducing H2S emissions. These advantages lead to improved safety and mean that the dosage does not have to be continuously adjusted to avoid depressing the ore. The mixtures also allow the use of smaller quantities of the sulfidizing agent, thus minimizing the amounts of reagents consumed. Furthermore, the use of a sulfidizing agent according to the first aspect of the invention does not require modification of the plant and / or installation of additional equipment, such as cells (i.e., flotation cells). In a second aspect, the invention provides a process for recovering one or more metallic ores and / or polymetallic minerals from the gangue, the process comprising: (i) treating the one or more metallic ores and / or polymetallic minerals with a sulfidizing agent; and (ii) separating the treated metallic ores and / or polymetallic minerals by using a sulfide flotation process; wherein the sulfidizing agent is obtainable by mixing MySx and ZSH in a weight ratio of 90:10 to 10:90, wherein M is selected from Li+, Na+, K+, Rb+, Cs+, NH4+, Mg2+ or Ca2+, and is 1 or 2, x is from 1.1 to 5, and Z is selected independently from Li+, Na+, K+, Rb+, Cs+ and NH4+. Page 4 of 35 1606582 of 36 This process provides a safer, faster, less expensive, and more reliable route for recovering one or more metallic ores and / or polymetallic minerals from the gangue, including that from a copper mine. In particular, the process increases the yield of a selective sulfide flotation process by sulfidizing at least a portion of the metallic ores and / or oxidized polymetallic minerals contained in the gangue that would otherwise go unrecovered. Figures Figure 1 is a schematic of the flotation stages performed, and the different fractions collected, in Example 1 and Example 4. Figure 2 is a schematic of the flotation stages performed, and the different fractions collected, in Example 2. Figure 3 shows the results of the flotation kinetic tests of Example 2, when using a sulfidizing agent comprising a mixture of Na2S4 and NaSH in a weight ratio of 1:1 compared to no use of sulfidizing agent (Figure 3A showing the total copper recovery and Figure 3B showing the oxidized copper recovery). Detailed description As stated above, the present description is directed to a sulfidizing agent obtainable by mixing MySx and ZSH in a weight ratio of 90:10 to 10:90, wherein M is selected from Li+, Na+, K+, Rb+, Cs+, NH4+, Mg2+ or Ca2+, and is 1 or 2, x is from 1.1 to 5, Z is selected independently from Li+, Na+, K+, Rb+, Cs+ and NH4+. Preferably, x has a value of 1.1 to 4.5, preferably from 2.1 to 4, and most preferably from 3 to 4. To obtain the highest sulfur content while maintaining good stability, x preferably has a value of 4. Page 5 of 35 1606582 of 36 M and / or Z is preferably Li+, Na+, K+, Rb+ or Cs+, with greater preference for K+ or Na+ and with the highest preference for Na+. In a preferred form, MySx is Na2S4 and / or ZSH is NaSH. MySx and ZSH can be mixed in a weight ratio of 90:10 to 10:90, preferably 90:10 to 30:70, with greater preference from 90:10 to 50:50 and with maximum preference from 70:30 to 50:50. When MySx is mixed with ZSH to prepare the sulfidizing agent of the invention, a new polysulfide composition (MySx) is formed, where the value of x varies depending on the weight ratio of the MySx / ZSH mixture used. For example, when NaSH is mixed with Na2S4, the NaSH effectively reduces the x value of Na2S4 from 4, forming a new polysulfide composition with an average x value that depends on the weight ratio of the NaSH / Na2S4 mixture used. This dependence of x on the weight ratio is quantified in the following table: NaSH / Na2S4 mixing ratio resulting x value 10 : 90 3.25 30 : 70 2.23 50 : 50 1.67 70 : 30 1.23 This variation in the resulting x values ​​means that by mixing MySx and ZSH in different weight ratios, the sulfidizing agent of the present invention can be tailored to the requirements of an individual mine. When the sulfidizing agent of the invention is used to aid the recovery of one or more metallic ores and / or polymetallic minerals in a sulfide flotation process, a collector, and optionally a frother, is required to separate the sulfidized metallic ores / polymetallic minerals by flotation, as described above. Therefore, when used with a collector and optional frother, the sulfidizing agent of the invention is a metal promoter. Page 6 of 35 1606582 of 36 oxidized and the combination is able to increase the performance of a selective sulfide flotation process by sulfidizing and floating at least a portion of the metallic ores and / or oxidized polymetallic minerals contained in the gangue that would otherwise not be recovered. The sulfidizing agent may include at least one collector. Preferably, the at least one collector is a monothiophosphate or dithiophosphate collector. Suitable monothiophosphate collectors include sodium diethylmonothiophosphate, sodium di-sec-butylmonothiophosphate, sodium diisobutylmonothiophosphate, and sodium diisoamylmonothiophosphate. Suitable dithiophosphate collectors include monoalkyldithiophosphates, such as sodium ethyldithiophosphate, sodium propyldithiophosphate, sodium isopropyldithiophosphate, sodium butyldithiophosphate, sodium butyldithiophosphate, sodium sec-butyldithiophosphate, and sodium isobutyldithiophosphate; dialkyldithiophosphates, such as sodium diethyldithiophosphate, sodium di-sec-butyldithiophosphate, sodium diisobutyldithiophosphate, and sodium diisoamyldithiophosphate; and diaryldithiophosphates, such as sodium dicresyldithiophosphate. The sulfidizing agent may include a mixture of two or more monothiophosphate and / or dithiophosphate collectors. When included, at least one collector may be present in the sulfidizing agent in an amount of 1 to 20% by weight, more preferably 5 to 10% by weight, based on the total weight of the sulfidizing agent. In particular, the sulfidizing agent may comprise a mixture of MySx, ZSH, and a collector in a weight ratio of (MySx and ZSH) : collector from 99:1 to 80:20, more preferably from 95:5 to 90:10. In particular embodiments, the sulfidizing agent may comprise a mixture of MySx, ZSH, and a collector in a weight ratio of 50:50:0 to 40:40:20, preferably from 49:49:2 to 47:47:6. The sulfidizing agent may include at least one foaming agent. The at least one foaming agent may be selected from the group of phenols, alkyl sulfates, aliphatic alcohols, generally C5-C8 cyclic alcohols, alkoxyalkanes, polypropylene glycol ethers, polyglycol ethers, polyglycol-glycerol ethers, pyridine bases, natural oils such as terpineol (pine oil) and cresols, ethers Page 7 of 35 1606582 of 36 mixed, aldehyde and ketone by-products from the production of oxoalcohols, and ethoxylated alcohols. Preferably, at least one foaming agent is a polyglycol, for example, a polypropylene glycol ether, a polyglycol ether, or a polyglycol-glycerol ether. The sulfidizing agent may include a mixture of two or more foaming agents. When included, at least one foaming agent may be present in the sulfiding agent in an amount of 1 to 20% by weight, more preferably 5 to 10% by weight, based on the total weight of the sulfiding agent. In particular, the sulfiding agent may comprise a mixture of MySx, ZSH, and at least one foaming agent in a weight ratio of (MySx and ZSH) : foaming agent from 99:1 to 80:20, more preferably from 95:5 to 90:10. In particular embodiments, the sulfiding agent may comprise a mixture of MySx, ZSH, and foaming agent in a weight ratio of 50:50:0 to 40:40:20, preferably from 49:49:2 to 47:47:6. As explained earlier, when the sulfidizing agent contains a collector and / or a frother, it becomes a promoter of metal oxidation. Furthermore, the inclusion of a collector and / or a frother in the sulfidizing agent optimizes any dosage for a sulfide flotation process and substantially reduces storage requirements. When both a collector and a frother are included, the sulfidizing agent can comprise a mixture of MySx, ZSH, collector, and frother in a weight ratio of (MySx and ZSH) : collector : frother from 98:1:1 to 60:20:20, with a higher preference for 90:5:5 to 80:10:10. In a preferred embodiment, the sulfidizing agent comprises a mixture of MySx, ZSH, collector and foaming agent in a weight ratio of 49:49:1:1 to 35:35:15:15, and more preferably from 45:45:5:5 to 40:40:10:10. The present invention further relates to a process for recovering one or more metallic ores and / or polymetallic minerals from gangue, the process comprising: (i) treating the one or more metallic ores and / or polymetallic minerals with a sulfidizing agent; and Page 8 of 35 1606582 of 36 (ii) separate the treated metallic ores and / or polymetallic minerals by using a sulfide flotation process; wherein the sulfidizing agent is obtainable by mixing MySx and ZSH in a weight ratio of 90:10 to 10:90, wherein M is selected from Li+, Na+, K+, Rb+, Cs+, NH4+, Mg2+ or Ca2+, and is 1 or 2, x is from 1.1 to 5, and Z is selected independently from Li+, Na+, K+, Rb+, Cs+ and NH4+. Preferably, x has a value of 1.1 to 4.5, preferably from 2.1 to 4, and most preferably from 3 to 4. To obtain the highest sulfur content while maintaining good stability, x preferably has a value of 4. M and / or Z is preferably Li+, Na+, K+, Rb+ or Cs+, with greater preference for K+ or Na+ and with the highest preference for Na+. In a preferred form, MySx is Na2S4 and / or ZSH is NaSH. MySx and ZSH can be mixed in a weight ratio of 90:10 to 10:90, preferably 90:10 to 30:70, with a higher preference of 90:10 to 50:50, and with the highest preference of 70:30 to 50:50. As mentioned earlier, the weight ratio of the MySx and ZSH mixture can be varied to adjust the average value of x in the resulting polysulfide composition. This means that the sulfidizing agent can be tailored to the individual requirements of any mine. The sulfidizing agent may include at least one collector and / or at least one foaming agent. Illustrative collectors and foaming agents, and their appropriate quantities, are set forth in connection with the first aspect of the preceding invention. Alternatively, at least one collector and / or at least one foaming agent may be added to one or more metallic ores and / or polymetallic minerals separately from the sulfidizing agent. The process of the present invention is used to recover one or more metallic ores and / or polymetallic minerals from the gangue. The one or more metallic ores may be selected from copper (Cu), molybdenum (Mo), gold (Au), silver (Ag), or lead ores. Page 9 of 35 1606582 of 36 (Pb), nickel (Ni), and cobalt (Co). Preferably, one or more metallic ores are selected from copper, molybdenum, silver, and gold ores, with copper ores being the most preferred. Examples of possible polymetallic ores include Cu-Mo, Cu-Au, Pb-Zn-Cu, Ag-Cu, Zn-Pb-Ag, Cu-Zn-Pb-Ag, Sn-Cu, and Zn-Pb ores. Preferably, the metallic ore and / or polymetallic ores contain at least 1% by weight of oxidized ore relative to the total ore. In stage (i) of the process, one or more metallic ores and / or polymetallic minerals are treated with the sulfidizing agent. The treatment in stage (i) can be carried out by adding the sulfidizing agent to the one or more metallic ores and / or polymetallic minerals in an amount of 1 to 300 g / ton, preferably 10 to 100 g / ton, with greater preference 20 to 70 g / ton, based on a dosage of grams of agent per ton of dry ore / dry mineral treated. When the sulfidizing agent includes at least one collector, the treatment in step (i) can be carried out by adding the sulfidizing agent to one or more metallic ores and / or polymetallic minerals in an amount of 1 to 400 g / ton, preferably 10 to 130 g / ton, more preferably 20 to 90 g / ton, based on a dosage of grams of agent per ton of dry ore / dry mineral treated. When the sulfidizing agent includes at least one foaming agent, the treatment in step (i) can be carried out by adding the sulfidizing agent to one or more metallic ores and / or polymetallic minerals in an amount of 1 to 400 g / ton, preferably 10 to 130 g / ton, more preferably 20 to 90 g / ton, based on a dosage of grams of agent per ton of dry ore / dry mineral treated. When the sulfidizing agent includes at least one collector and at least one frothing agent, the treatment in stage (i) can be carried out by adding the sulfidizing agent to one or more metallic ores and / or polymetallic minerals in an amount of 2 to 500 g / tonne, preferably 10 to 160 g / tonne, with Page 10 of 35 1606582 of 36 greater preference of 20 to 100 g / ton, based on a dose of grams of agent per ton of dry ore / dry mineral treated. The sulfidizing agent is preferably added to one or more metallic ores and / or polymetallic minerals in at least two, preferably at least three, and most preferably at least four additions. The time intervals between the additions and / or the quantity of each addition may be the same or different, preferably different. Each portion of sulfidizing agent added to one or more metallic ores and / or polymetallic minerals requires the addition of at least one collector, and optionally at least one frothing agent, so that the extra “sulfidized” material produced by the sulfidizing agent can be recovered. When the at least one collector and / or at least one frothing agent are added to one or more metallic ores and / or polymetallic minerals separately from the sulfidizing agent, the collector(s), frothing agent(s), and sulfidizing agent may be added in any order. Preferably, the at least one collector and / or at least one frothing agent are added to one or more metallic ores and / or polymetallic minerals before or at the same time as the sulfidizing agent. Preferably, no sulfidizing agent is added to the one or more metallic ores and / or polymetallic minerals before the flotation process begins. Instead, it has been found advantageous to delay the first addition of a sulfidizing agent to the one or more metallic ores and / or polymetallic minerals until at least 1 minute, preferably at least 2 minutes, and more preferably at least 3 minutes after the flotation process begins. Preferably, the delay is no longer than 5 minutes, and more preferably no longer than 4 minutes. In a preferred embodiment, a first portion of sulfidizing agent is added to one or more metallic and / or polymetallic ores in a more severe flotation stage of the sulfide flotation process, and an additional portion of Page 11 of 35 1606582 of 36 sulfidizing agent to one or more metallic ores and / or polymetallic minerals in at least one cleaning stage of the sulfide flotation process. Preferably, an additional portion of sulfidizing agent is added to one or more metallic ores and / or polymetallic minerals in each cleaning stage of the sulfide flotation process. In a preferred embodiment, at least a first and a second portion of sulfidizing agent is added to one or more metallic and / or polymetallic ores in the most severe flotation stage of the sulfide flotation process. In particular, at least two, three, four, six, or eight portions of sulfidizing agent may be added to the most severe flotation stage of the sulfide flotation process. When at least a first and a second portion of sulfidizing agent are added to one or more metallic and / or polymetallic ores in the most severe flotation stage of the sulfide flotation process, these portions can be separated by a more severe concentrate grinding (refining) stage downstream of the most severe flotation and upstream of the cleaning flotation. In processes with intermediate grinding (refining), the surface effect obtained by the sulfidizing agent is partially eliminated, and therefore a subsequent dose of sulfidizing agent is advantageous to recover the yield lost in this stage. The sulfidizing agent (when free of collector and frother) can be added to the more severe flotation stage and cleaning stages in amounts proportional to the solubility ratio (oxidized copper to total copper) of the ore / mineral as shown in Table A: Page 12 of 35 1606582 of 36 Table A Solubility ratio Dosage in a more severe flotation stage Dosage in cleaning stages 3-10% 10-50 g / ton 3-8 g / ton 10-20% 30-100 g / ton 7-12 g / ton >20% >70 g / ton >15 g / ton As explained earlier, the dosage amount for each stage shown in Table A can be divided into two or more portions. The amount of each dosage portion can be the same or different, preferably different. In stage (ii) of the process, the treated metallic ores and / or polymetallic minerals are separated from the gangue using a sulfide flotation process. Preferably, the process is a direct flotation of the treated metallic ores and / or polymetallic minerals. More specifically, in a preferred embodiment where the sulfidizing agent does not contain a collector or a foaming agent, the process comprises the following steps: a) mixing a ground ore / mineral with an aqueous medium to form a pulp; b) condition the pulp with a collector, and optionally a foaming agent, as described above; c) feed the conditioned ore / mineral mixture into a more severe flotation cell; d) introduce air into the most severe flotation cell to initiate the froth flotation process to recover the ore / mineral; e) after a delay of at least 1 minute, add a portion of the sulfidizing agent as described above to the most severe flotation cell along with additional collector and frothing agent; f) Optionally, add a second portion of the sulfidizing agent along with a collector and foaming agent to the more severe flotation cell; g) remove the foam formed (more severe concentrate) and feed it to a cleaning cell; and Page 13 of 35 1606582 of 36 h) Add an additional portion of the sulfidizing agent along with a collector and a foaming agent in the cleaning cell. It is observed that several elements of the present invention, including, but not limited to, the preferred ranges for the various parameters, can be combined unless they are mutually exclusive. The invention will be clarified by the following examples, without being limited to these or in this manner. Examples Example 1: Copper and gold recovery from mineral samples from the Coquimbo region, Chile Example 1 was performed using a mineral sample with the following composition: Sample Total Copper (%) Oxidized Copper (%) Solubility Ratio (%) Au (g / t) Ag (g / t) Example 1 1.93 0.261 13.52 1.0 6.45 Page 14 of 35 1606582 of 36 The Standard Float Protocol that was used was the following: Parameter Unit Flotation Machine - Type Agitair Cell Volume L 2.7 Agitation rpm 1100 Percent Solids % 30 Flotation pH - 10.00 (with calcium oxide) Feed Particle Size 70% through a 200 mesh (74 μm), in accordance with ASTM E11-20 (Standard Specification for Woven Wire Test Mesh Cloth and Test Sieves, 2020) Conditioning Time minutes 3 Paddle Frequency seconds 15 Air Flow L / minute 0 - 3 minutes: 1.5 3 - 10 minutes: 2.5 10 - 16 minutes: 4.0 Extraction Times minutes 2 (first), 16 (second) Water Type - Potable Water Water Temperature °C 20 (±1) Collector 208* (g / t) 48 (Conditioning) Collector 3894* (g / t) 24 (Conditioning) D-400§ Foam (g / t) 30 (Conditioning) *Supplied by Solvay §Supplied by Dow Chemicals Details of the work protocol: 1.1 Mechanical preparation An ore sample containing 1.93% copper (of which 0.261% was oxidized copper) and 1.0 g / t gold was ground to a particle size of 100% through a 10 mesh (2000 μm) according to ASTM E11-20. Subsequently, the sample was homogenized and fractionated in a prodivider cutter (“carousel”), to generate the containers for the rectification and flotation tests. Page 15 of 35 1606582 of 36 1.2 Mineralogical analysis The following mineralogical species were observed, listed in order of relative abundance - Majority: magnetite - In smaller quantities: pyrite, chalcopyrite, hematite, bornite - Minority: digenite, covellite, chalcocite, tennantite-tetrahedrite - In traces: limonite, galena, sphalerite, native Cu, brandsite, pyrhotine Summary table of mineralogical compositions (expressed as % by weight): SPECIES FORMULA Cu sulfides Chalcopyrite 4.31 CuFeS2 Chalcosine 0.13 Cu2S Digenite 0.16 Cu9S5 Coveline Tr (1) CuS Bornite 0.18 Cu5FeS4 Native Copper Tr (1) Cu Other sulfides Pyrite 2.09 FeS2 Molybdenite 0.02 MoS2 Sphalerite Tr (1) (Zn, Fe)S Galena Tr (1) PbS Marcasite Tr (1) FeS2 Pyrrhotite Tr (1) FeS Metal oxides Magnetite 33.24 Fe2+Fe3+2 O4 Hematite 0.62 Fe2O3 Limonite 0.06 FeO(OH)nH2O Rutile 0.04 TiO2 Non-metallic minerals (gangue) 59.16 Undetermined TOTAL 100 (1) trace mineral that cannot be quantified As can be seen in this summary table, for copper, the useful species in this example, the ore is formed primarily from primary sulfides. It was not possible to observe gold particles under the optical microscope. This is attributed to the excessively low purity (1.0 g / t Au). Page 16 of 35 1606582 of 36 1.3 More severe kinetic flotation tests 1.3.1 Ten kilograms of single-size, 1-inch steel ball grinding media were placed in a laboratory batch mill, and potable water was added in sufficient quantity to obtain the 66.67% solids required for grinding. The ore was then charged (with a charge of 1000 g) into the mill and ground to obtain a grain size of 70% passing a 200-mesh screen (ASTM E11-20). (Summary of Mill Additions: ore = 1000 g; water = 500 mL). 1.3.2 The pulp (the mixture of ground ore and water) was placed in an Agitair flotation cell with a volume of 2.7 L. Potable water was added to adjust the pulp to 30% solids and the pH was measured (natural value, pH 8). Then, the flotation machine was started (or energized) to agitate the pulp, and 48 g / t of collector 208, 24 g / t of collector 3894, and 30 g / t of frothing agent were added. The pulp was conditioned for 3 minutes without air injection. After the pulp conditioning stage, froth removal began with 4 paddles per minute (every 15 seconds), ensuring coverage of the entire flotation surface. Concentrates were collected in separate containers (trays) and labeled “2 minutes” and “16 minutes.” The entire test was conducted at room temperature (20 ± 1 °C). In the case of the tests with sulfidizing agents, 130.6 g / t of sulfidizing agent was added after 2 minutes of flotation (after the first concentrate had been extracted), which comprised a mixture of Na2S4 and NaSH in a weight ratio of 1:1. After 30 seconds of airless conditioning, the extraction of the concentrate was continued. 1.3.3 The most severe concentrates and the most severe tailings were collected, filtered, dried and cooled, before being mechanically prepared (100% through 140-105 μm mesh) for chemical analysis according to the usual procedure for such activities (detailed below). Page 17 of 35 1606582 of 36 1. Filter the concentrates and tailings under pressure in the pressure filter equipment (drum); 2. Transfer each filtered solid to a tray and dry in an oven at 100 ± 5 °C; 3. Weigh the concentrates and dry tailings and, by the difference in weight, obtain the recovered mass; 4. Transfer the tailings to a rolling cloth and break them up with a roller to homogenize them; 5. Divide the tailings and obtain a sample for chemical and control testing; 6. Pulverize samples (100% through 140 mesh) of tailings and concentrates for chemical testing. 1.3.4 The chemical composition of the main ore, concentrates, and tailings was established by determining the total Cu, Au, and soluble (oxidized) Cu. Cu and Ag were determined using Atomic Absorption Spectroscopy (with an Atomic Absorption Spectrophotometer). Au was tested using the Fire Refining (Docimasy) method in a furnace. Soluble Cu was obtained using the citric acid etching method (with atomic absorption spectroscopy). The same test was performed without using a sulfidizing agent, and the results of each test are summarized in Table 1. Table 1: Results of metal recovery tests with and without sulfidizing agent of the present invention Sulfidizing Agent Recovery (%) Total Copper Oxidized Copper Gold Na2S4 / NaSH (1:1) 94.03 75.39 93.47 None 88.28 48.83 91.51 The results show that the use of a sulfidizing agent comprising a mixture of Na2S4 and NaSH in a 1:1 weight ratio increases the recovery of Page 18 of 35 1606582 of 36 total copper and total gold from the mineral sample. A significant improvement in the recovery of soluble (i.e., oxidized) copper is also seen. Figure 1 schematically illustrates the flotation process and the different fractions collected. Here: A is the pulp feed, 1 is the mill, 2 and 3 are the more severe flotation cells, 4 is the conditioning stage, where 48 g / t of collector 208, 24 g / t of collector 3894, and 30 g / t of frothing agent (pH 8.0; 30 wt% solids) are added, 5 is in a flotation time of 2 minutes, where 65.3 g / t of Na2S4 and 65.3 g / t of NaSH are added, 6 is the more severe tailings, and 7 is the more severe concentrate. Example 2: Recovery of copper and molybdenum from a mineral sample from the Valparaíso region, Chile Example 2 was performed using a mineral sample with the following composition: Sample Total Copper (%) Oxidized Copper (%) Solubility Ratio (%) Mo (%) Fe (%) Example 2 0.55 0.133 23.63 0.0092 4.35 Page 19 of 35 1606582 of 36 The standard flotation protocol used was as follows: Parameter Unit Flotation Machine - Denver Cell Volume L 4.0 Agitation rpm 1000 Percent Solids % 35 Flotation pH - 10.50 (with calcium oxide) Feed Particle Size P80 = 250 μm (80% passing a 250 μm sieve) Conditioning Time minutes 3 Paddle Frequency seconds 15 Air Flow L / minute 10 Water Temperature °C 20 (±1) Extraction Times minutes 0.5, 1, 3, 4, 7, 10.5, 15 Water Type Process Water Diesel (g / t) 12 Collector Hostaflot-71695 (g / t) 24 total 60% in conditioning 40% in flotation = 4 minutes (30 seconds without air, 30 seconds with air) Foam MatFroth-50¥ (g / t) 24 total 60% in conditioning 40% in flotation = 4 minutes (30 seconds without air, 30 seconds with air) Sse suministro por Clariant; ¥se suministro por Mathiesen Details of the work protocol: 2.1 Mechanical preparation A mineral sample containing 0.55% copper (of which 0.133% was oxidized copper) and 0.0092% Mo was ground to a grain size of 100% through a 10 mesh (2000 μm) ASTM E11-20. Subsequently, the sample was homogenized and fractionated in a prodivider cutter (“carousel”), to generate the containers for the rectification and flotation tests. 2.2 Mineralogical analysis The following mineralogical species were observed: Page 20 of 35 1606582 of 36 Summary table of mineralogical compositions: Mineral % by weight at a granularity of 250 pm Chalcocite 0.19 Covellite 0.06 Chalcopyrite 1.03 Bornite 0.05 Enargite / Tennantite 0.00 Native Copper 0.00 Cuprite / Tenorite 0.00 Malachite / Azurite 0.00 Brochantite 0.01 Atacamite 0.00 Turquoise 0.00 Pseudomalachite 0.00 Cu-Mn Vapor 0.00 Chrysocolla / Dioptase 0.05 Cu-bearing Clays 0.01 Cu-bearing Fe Ox / OH 0.01 Other Cu Minerals 0.01 Pyrite 2.01 Galena 0.00 Sphalerite 0.01 Molybdenite 0.01 Fe Oxides 3.32 Ilmenite 0.44 Rutile 0.50 Corundum 0.00 Quartz 38.94 Orthoclase 5.51 Albite 6.64 Plagioclase 1.53 Muscovite / Sericite 29.78 Kaolinite 0.56 Pyrophyllite / Smectite 0.28 Biotite 1.18 Chlorite 6.86 Hornblende 0.22 Calcite / CO3 0.00 Gypsum / Anhydrite 0.03 Alunite 0.02 Jarosite 0.03 Page 21 of 35 1606582 of 36 Mineral % by weight at a granularity of 250 μm Mg-SO4 0.00 Barite 0.01 Svanbergite 0.00 Fe-Al-PO4 0.01 Apatite 0.37 Monazite 0.01 Zircon 0.01 Other 0.27 Total 100.00 As can be seen in this summary table, for copper, i.e., the useful species in this example, the ore is formed primarily by chalcopyrite (i.e., primary sulfide, 58.20%), with minor fractions of chalcocite, covellite, and bornite (secondary sulfides, 35.57%). The remaining copper is found in oxidized species (cuprite / tenorite, malachite / azurite, chrysocolla / dipotase, brochantite). The copper-bearing species are further detailed below. Page 22 of 35 1606582 of 36 Species containing Cu (expressed as % by weight of the total copper-containing species): Copper ore % by weight at a granularity of 250 pm Chalcocite 24.09 Covellite 6.75 Chalcopyrite 58.20 Bornite 4.73 Enargite / Tennantite 0.01 Native Copper 0.24 Cuprite / Tenorite 0.63 Malachite / Azurite 0.18 Brochantite 0.83 Atacamite 0.01 Turquoise 0.00 Pseudomalachite 0.04 Cu-Mn vapor 0.01 Chrysocolla / Dioptase 3.14 Cu-bearing clays 0.23 Cu-bearing Fe Ox / OH 0.14 Other Cu minerals 0.53 Other 0.25 Total 100.00 2.3 More Severe Kinetic Buoyancy Tests 2.3.1 Ten kilograms of single-size, 1-inch steel ball grinding media were placed in a laboratory batch mill, and potable water was added in sufficient quantity to obtain the 66.67% solids required for grinding. The ore was then charged (with a charge of 1800 g) into the mill and ground to obtain a particle size of Ps0 = 250 pm. (Summary of addition to the mill: ore = 1800 g; water = 900 mL). 2.3.2 The pulp (the mixture of ground ore and water) was loaded into a Denver flotation cell with a volume of 4.0 L, then process water was added to adjust to 35% solids and the pH (natural value) was measured. Page 23 of 35 1606582 of 36 The details of the most severe flotation process are as follows (the entire test is carried out at room temperature (20 ± 1 °C)): a) Start agitating the pulp in the flotation cell (for 15-30 seconds); b) Measure the pH of the pulp and adjust it to 10.5 using 12% calcium hydroxide; c) Add 14.4 g / t of Matfroth 50 foaming agent (60% of a total dose of g / t), 14.4 g / t of Hostaflot-7169 collector (60% of a total dose of 24 g / t) and 12 g / t of diesel oil; d) Condition the pulp for 2 minutes without air injection and for 1 minute with air injection; e) After the conditioning stage, foam extraction began using 4 paddles, ensuring that the entire flotation surface was covered. Taking the first sample sweep should be considered as “0 minutes”; f) Continue foam extraction with 4 paddles every 15 seconds and obtain concentrates in separate containers for the 0.5 - 1 - 3 minute extractions; g) Continue extracting the sample with paddles every 15 seconds for 3 to 10 minutes; h) Cut off the air injection at minute 4 from the start of the float test; i) Add the remaining 40% dose of Matfroth 50 foaming agent and the remaining 40% dose of Hostaflot-7169 collector; j) Condition the pulp for 30 seconds without air injection and with air injection for 30 seconds; k) Restart sample extraction with paddles every 15 seconds and collect concentrates in separate containers for extractions after 4-7 and 10.5-15 minutes. Ensure the entire flotation surface is covered. The first sample sweep should be considered as "0 minutes" of this second flotation stage. In the case of the tests with sulfidizing agents, 27.5 g / t of sulfidizing agent was added after 4 minutes of flotation (after the first concentrate had been extracted), comprising a mixture of Na2S4 and NaSH in a 1:1 weight ratio. After 30 seconds of Page 24 of 35 1606582 of 36 airless conditioning, and 30 seconds with air, the extraction of the concentrate continued. A procedure similar to the 7-minute flotation was carried out, with a readmission of the sulfidizing agent. 2.3.3 The concentrates and tailings were then collected, filtered, dried and cooled, before being mechanically prepared (100% through 140-105 μm mesh) for chemical analysis according to the usual procedure for such activities (described below). 1. Filter the concentrates and tailings obtained under pressure in the pressure filter equipment (drum); 2. Transfer each filtered solid to a tray and dry in an oven at 100 ± 5 °C; 3. Weigh the concentrates and dry tailings and, by the difference in weight, obtain the recovered mass; 4. Transfer the tailings to a rolling cloth and disintegrate with a roller to homogenize; 5. Divide the tailings and obtain a sample for chemical and control testing; 6. Pulverize samples (100% through 140 mesh) of tailings and concentrates for chemical testing. 2.3.4 The chemical composition of the main ore, concentrates, and tailings was established by determining the total Cu, Fe, Mo, and soluble (oxidized) Cu. The elements Cu, Fe, and Mo were determined using atomic absorption spectroscopy (with an atomic absorption spectrophotometer). Soluble Cu was obtained using citric acid etching (with atomic absorption spectroscopy). 2.4 Cleaner kinetic flotation tests 2.4.1 More severe flotation to generate a more severe concentrate To obtain sufficient mass of more severe concentrate to allow the cleaner flotation kinetic test to be carried out, a 3x flotation was performed. Page 25 of 35 1606582 of 36 severe, in a total time of 15 minutes, and the most severe concentrates generated in the tests were combined. 2.4.2 Regrinding of the most severe concentrate Ten kilograms of single-size, 1-inch steel ball grinding media were loaded into a laboratory batch mill, and the most severe concentrated pulp was added and drained to obtain the 50% solids required for grinding. The most severe concentrated pulp was then reground to obtain a granulation of P80 = 44 μm. (Summary of pulp addition to the mill: most severe concentrate = approximately 235 g (dry basis); water = 1071 mL). 2.4.3 The pulp (the mixture of ground coarse concentrate and water) was placed in a Denver flotation cell with a volume of 1.15 L, and process water was added to adjust to 18% solids. The pH was then measured. The details of the cleaner flotation process are as follows (the entire test is carried out at room temperature (20 ± 1 °C)): - Start agitating the pulp in the flotation cell (for 15-30 seconds); - Measure the pH of the pulp and adjust it to 11.0 using 12% calcium hydroxide; - Add 1.12 g / t of Matfroth 50 foaming agent and 0.9 g / t of Hostaflot-7169 collector; - Condition the pulp for 30 seconds without air injection and for 30 seconds with air injection; - After the conditioning stage, begin skimming the foam with 4 paddles, making sure to cover the entire flotation surface. Taking the first sample sweep should be considered as “0 minutes”; - Continue foam extraction with 4 paddles every 10 seconds and obtain concentrates in separate containers for extractions of 0.5 - 1 - 3 - 6 minutes; - Continue sample extraction with paddles every 15 seconds; Page 26 of 35 1606582 of 36 - Cut off the air injection at minute 12 from the start of the float test; - Add 1.12 g / t of Matfroth 50 foaming agent; - Condition the pulp for 30 seconds without air injection and with air injection for 30 seconds; - Restart sample extraction with paddles every 10 seconds and collect concentrates in separate containers for the 12, 18, and 30-minute extractions, ensuring coverage of the entire flotation surface. The first sample sweep should be considered as "0 minutes" of this second flotation stage. In the case of the tests with sulfiding agents, 4.0 g / t of sulfiding agent, comprising a mixture of Na2S4 and NaSH in a 1:1 weight ratio, was added after 12 minutes of flotation (following the extraction of the first concentrate). After 30 seconds of conditioning without air, and 30 seconds with air, the extraction of the concentrate continued. A similar procedure was performed after 18 minutes of flotation, with the re-addition of the sulfiding agent. 2.4.4 The cleaner concentrate, cleaner tailings and more severe tailings were then collected, filtered, dried and cooled, before being mechanically prepared (pulverized to obtain 100% through a 140 105 μm mesh) for chemical analysis according to the usual procedure for such activities (described in 2.3.3 above). 2.4.5 The chemical composition of the main ore, concentrates and tailings was established by determining the total Cu, Fe, Mo and soluble (oxidized) Cu. The elements Cu, Fe, and Mo were determined by atomic absorption spectroscopy (using an atomic absorption spectrophotometer). Soluble Cu was obtained by citric acid etching (using atomic absorption spectroscopy). Page 27 of 35 1606582 of 36 The same tests were performed without the use of a sulfidizing agent or with the use of NaSH as the sole sulfidizing agent, and the results of each test are summarized in Table 2. Table 2: Results of metal recovery tests with sulfidizing agent of the present invention, NaSH or none Sulfidizing Agent Recovery (%) Total Copper Oxidized Copper Molybdenum Na2S4 / NaSH (1:1) 78.19 54.35 50.63 NaSH 73.50 46.87 48.47 None 64.17 35.87 48.09 The results show that using a sulfidizing agent comprising a mixture of Na2S4 and NaSH in a 1:1 weight ratio increases the recovery of total copper and total molybdenum from the mineral sample compared to using NaSH alone. A significant improvement in the recovery of soluble (i.e., oxidized) copper is also observed. In Figure 2, the flotation process carried out, and the different fractions collected, are illustrated schematically. Here: A is the pulp feed, 1 is the mill, 2, 3, and 4 are more severe flotation cells, 5 is the conditioning stage, where 14.4 g / t of Hostaflot-7169, 14.4 g / t of Matfroth 50, and 12 g / t of diesel oil (pH 10.5, with lime) are added, 6 is in a 4-minute flotation stage, where 9.6 g / t of Hostaflot-7169, 9.6 g / t of Matfroth 50, 13.75 g / t of Na2S4, and 13.75 g / t of NaSH are added, 7 is in a 7-minute flotation stage, where 13.75 g / t of Na2S4 and 13.75 g / t of NaSH are added, 8 is the more severe tailings, 9 is the more severe concentrate, 10 is the mill for regrinding the more severe concentrate, 11, 12 and 13 are cleaner flotation cells, 14 is the cleaner conditioning stage, where 0.9 g / t of Hostaflot-7169 and 1.12 g / t of Matfroth 50 (pH 11.0, with lime) are added, 15 is in a flotation time of 12 minutes,where 1.12 g / t of Matfroth 50, 2 g / t of Na2S4 and 2 g / t of NaSH are added, 16 is in a flotation time of 18 minutes, where the following are added, Page 28 of 35 1606582 of 36 g / t of Na2S4 and 2 g / t of NaSH, 17 are the cleanest tailings and 18 is the cleanest concentrate. The flotation kinetics for total copper recovery and soluble (i.e., oxidized) copper recovery when using a sulfidizing agent comprising a mixture of Na2S4 and NaSH in a weight ratio of 1:1 (“STANDARD + SULFIDIZING”) compared to without the use of a sulfidizing agent (“STANDARD”) are shown in Figure 3. Example 3: Recovery of copper and silver from a mineral sample from the Cuzco region, Peru A mineral sample containing 0.452% copper (of which 0.121% is oxidized copper) and 3.505 ppm silver was ground to a suitable flotation size. The sample was then placed in a Denver flotation cell and mixing was initiated. The sample was subsequently conditioned with a collector and frother. After the conditioning stages, water was added to obtain a total pulp volume of 2.3 L with 35% solids and a pH of 10.5, and flotation was initiated. The most severe flotation was carried out at RT (20 ± 1 °C) with agitation at 1150 rpm. After a slight delay, a sulfidizing agent comprising a mixture of Na2S4 and NaSH in a weight ratio of 70:30 was added to the flotation cell. The most severe flotation was followed by two cleaning stages. The concentrate was collected and analyzed. The process was carried out using different doses of the sulfidizing agent. The recovery results are summarized in Table 3. Page 29 of 35 1606582 of 36 Table 3: Results of metal recovery tests with different doses of sulfidizing agent Na2S4 / NaSH (70:30) Test (g / ton of dry ore) Recovery (%) Copper Concentrate Obtained (%) Copper Silver 3.1 0 60.50 16.10 5.5 3.2 15 70.00 23.00 6.7 3.3 30 79.30 20.20 5.7 The results show that significant improvements in copper and silver recovery were achieved with much lower doses than those required when using NaSH as a sulfidizing agent (i.e., >100 g / ton of dry ore). This is believed to be due to the higher sulfur content in the formulation. The copper concentrate concentrations obtained in tests 3.2 and 3.3 were also higher than those in test 3.1. This means that the sulfidizing agent of the invention produces a higher quality (i.e., more concentrated) final copper product. Test 3.2 was repeated, but an initial and additional dosage of 15 g / ton of dry ore of the sulfidizing agent was added at the grinding stage. The overall copper extraction yield was 59.1%. This result is worse than Test 3.2 and supports the preferred dosing regime, i.e., only after the flotation process has begun and in later flotation and cleaning stages, to improve extraction yields. Dosing at these points is believed to be advantageous because the oxide ores concentrate in the cell as flotation begins. Additionally, it has been found that the depressant power of NaSH in the sulfidizing agent mixture competes with the sulfidizing power (resulting in an undesirable effect) if the addition is made too early in the process. Example 4: Recovery of copper and silver from a mineral sample from the Antofagasta region, Chile Page 30 of 35 1606582 of 36 Example 4 was performed using a mineral sample with the following composition: Sample Total Copper (%) Oxidized Copper (%) Solubility Ratio (%) Ag (%) Fe (%) Example 4 0.642 0.093 14.49 0.0006 4.03 The Standard Float Protocol was as follows: Parameter Unit Flotation Machine - Type Wenco Cell Volume L 2.8 Agitation rpm 1200 Percent Solids % 38 Flotation pH - 10.00 (with calcium oxide) Feed Particle Size P80 = 260 pm (80% through a 260 pm sieve) Conditioning Time minutes 2 Paddle Frequency seconds 10 Air Flow L / Minute 10 Extraction Times minutes Standard: 1, 5, 15, 30 Water Type - Process Water Water Temperature °C 20 (±1) Matcol AP-7156 Collector (g / t) 25 (Grinding) MX-3753* Collector (g / t) 15 (Conditioning) MB-78* Froth (g / t) 20 (Conditioning) MIBC* Froth (g / t) 15 (Conditioning) ¥supplied by Mathiesen; *supplied by Solvay Details of the work protocol: 4.1 Mechanical preparation A mineral sample containing 0.642% copper (of which 0.093% was oxidized copper) and 0.0006% silver was ground to a particle size of 100% through a 10 mesh (2000 μm) according to ASTM E11-20. Subsequently, the sample was homogenized and fractionated in a Pro-Splitter cutter (“carousel”), to generate the containers for the grinding and flotation tests. Page 31 of 35 1606582 of 36 4.2 More severe kinetic flotation tests 4.2.1 Ten kilograms of single-size, 1-inch steel ball grinding media were loaded into a laboratory batch mill, and process water was added in an amount sufficient to obtain 66.67% of the solids required for grinding. The ore (at a charge of 1000 g) and the AP7156 collection reagent (0.025 g) were then loaded into the mill and ground to a particle size of P80 = 250 μm. (Mill Addition Summary: ore = 1000 g; AP-7156 collection reagent = 0.025 g; water = 500 mL). 4.2.2 The pulp (the mixture of ground ore, collector agent AP-7156 and water) was loaded into a Wenco flotation cell with a volume of 4.0 L, then process water was added to adjust to 38% solids and the pH was measured (natural value, on the order of 8). The details of the most severe flotation process are as follows (the entire test is carried out at room temperature (20 ± 1 °C): a) Start agitating the pulp in the flotation cell (for 15-30 seconds); b) Measure the pH of the pulp and adjust to 10 using 12% calcium oxide; c) Add 15 g / t of MX-3753 collector, 20 g / t of MB-78 foaming agent and 15 g / t of MIBC foaming agent; d) Condition the pulp for 2 minutes without injecting air; e) After the conditioning stage, start skimming off the foam with paddles, making sure to cover the entire flotation surface; Taking the first sample sweep should be considered as “0 minutes”; f) Continue foam extraction with 6 paddles every 60 seconds and obtain concentrates in separate containers for the 1 - 5 - 15 - 30 minute extractions; g) Stop the flotation process and thoroughly wash all parts (agitator, sample extraction paddle, etc.) to ensure that the resulting pulp contains all the solid material within the flotation cell. Page 32 of 35 1606582 of 36 4.2.3 In the case of tests with sulfidizing agents: after 7 minutes of flotation (after the first 2 concentrates had been extracted), sulfidizing agent was added according to Table 4. After 30 seconds of conditioning without air, and 30 seconds with air, the extraction of the concentrate continued. 4.2.4 The concentrates and tailings were collected, filtered, dried and cooled, before being mechanically prepared (100% through 140-105 μm mesh) for chemical analysis according to the usual procedure for such activities (described below). 1. Filter the concentrates and tailings obtained under pressure in the pressure filter equipment (drum); 2. Transfer each filtered solid to a tray and dry in an oven at 100 ± 5 °C; 3. Weigh the concentrates and dry tailings and, by the difference in weight, obtain the recovered mass; 4. Transfer the tailings to a rolling cloth and disintegrate with a roller to homogenize; 5. Divide the tailings and obtain a sample for chemical and control testing; 6. Pulverize samples (100% through 140 mesh) of tailings and concentrates for chemical testing. 4.2.5 The chemical composition of the main ore, concentrates, and tailings was established by determining total Cu and soluble (oxidized) Cu. Total Cu was determined using Atomic Absorption Spectroscopy (with an Atomic Absorption Spectrophotometer). Soluble Cu was obtained using the citric acid etching method (with atomic absorption spectroscopy). The same test was performed without the use of a sulfidizing agent, or with the use of NaSH as the only sulfidizing agent, and the results of each test are summarized in Table 4. Page 33 of 35 1606582 of 36 Table 4: Results of metal recovery tests with sulfidizing agent of the present invention, NaSH or none Sulfidizing Agent Dosage (g / t) Recovery (%) Total Copper Oxidized Copper None - 84.67 45.90 Na2S4 / NaSH (1:1) 70 90.53 82.93 Na2S4 / NaSH (3:7) 70 90.38 76.14 NaSH 70 89.61 74.77 Na2S4 / NaSH (1:1) 35 89.88 80.35 The results show that using a sulfidizing agent comprising a mixture of Na₂S₄ and NaSH in a weight ratio of 1:1 and 3:7 increases the overall copper recovery from the mineral sample compared to using neither the sulfidizing agent nor NaSH alone. A significant improvement in the recovery of soluble (oxidized) copper is also observed. Furthermore, as shown in the last row, a dosage of a mixture of Na₂S₄ and NaSH in a weight ratio of 1:1, which is 50% of the NaSH dosage, still demonstrates better performance than NaSH alone. In Figure 1, the flotation process carried out in Example 4, and the different fractions collected, are illustrated schematically. Here: A is the mill feed, 1 is the mill, 2 and 3 are the more severe flotation cells, 4 is the conditioning stage, where 15 g / t of collector MX-3753, 20 g / t of frothing agent MB-78 and 15 g / t of frothing agent MIBC (pH 10.0; 38 wt% solids) are added, 5 is in a flotation time of 7 minutes, where Na2S4 and / or NaSH are added, 6 are the more severe tailings and 7 is the more severe concentrate. In this description, unless expressly stated otherwise, the word 'or' is used in the sense of an operator that returns true when one or both of the stated conditions are met, as opposed to the 'exclusive or' operator, which requires that only one of the conditions be met. The phrase 'comprising' is used in the sense of 'including' rather than 'consisting of'. All previously acknowledged teachings are incorporated into this description by reference. No acknowledgment of any prior teachings should be deemed to constitute an endorsement of any prior teachings. Page 34 of 35 1606582 of 36 document previously published in the present description constitutes an admission or declaration that the teaching thereof was common general knowledge in Europe or elsewhere at the date of the present description. Page 35 of 35 1606582 of 36 PEDRO NICOLÁS MIRANDA HONAINE - 20307560667 Digitally signed by PORTALTRAM ITES - INPI Date: 2021.12.09 12:15:53 ​​-03:00 Reason: Digitally Signed by the INPI Location: Buenos Aires, Argentina 1606582

Claims

1. A sulfidizing agent characterized in that the agent is obtained by mixing MySx and ZSH in a weight ratio of 90:10 to 10:90, wherein M is selected from Li+, Na+, K+, Rb+, Cs+, NH4+, Mg2+ or Ca2+, and is 1 or 2, x is from 2.1 to 5, and Z is independently selected from Li+, Na+, K+, Rb+, Cs+ and NH4+. 14 Claims follow