Medicament system for alkaline desulfidizing and cyanide leaching of gold from sulfide ore and method for extracting gold

Abstract

The application provides a sulfide ore alkaline desulfurization cyanide leaching gold reagent system and a gold extraction method thereof, and belongs to the technical field of hydrometallurgy. The method constructs a ternary reagent system composed of potassium ferricyanide, low-concentration sodium cyanide and thioguanosine. An efficient "oxidation-inhibition" synergistic system is formed between the auxiliary desulfurization reagent potassium ferricyanide and thioguanosine. The rapid and selective oxidation of potassium ferricyanide is smoothly carried out under the synergistic action of thioguanosine, the mineral is completely decomposed, and the surface remains high activity; at the same time, the presence of thioguanosine can more directly eliminate the risk of local micro-area passivation and catalyze electron transfer. The two complement each other, and together guarantee that the subsequent low-concentration sodium cyanide can smoothly and unobstructedly leach the exposed gold with high efficiency, finally realizing the high recovery rate extraction of gold in the refractory sulfide ore while reducing the total consumption of reagents and environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, specifically to an alkaline desulfurization and cyanidation gold leaching agent system for sulfide ores (especially pyrite, arsenopyrite, and other sulfide ores) and a method for extracting gold from them. Background Technology

[0002] In the gold extraction industry, direct cyanide leaching is a mature and efficient process for conventional oxide ores. However, for ores containing large amounts of sulfide minerals (such as pyrite FeS2, pyrrhotite Fe), direct cyanide leaching is less effective. （1-x） The processing of ores containing sulfur (such as sulfides) has always been a technical challenge. The sulfur components in these ores have a serious negative impact on the cyanide gold extraction process: firstly, sulfides consume large amounts of cyanide and oxygen, generating thiocyanate (SCN). - First, the leaching process significantly increases reagent costs. Second, gold particles are often tightly encapsulated by sulfide minerals in the form of "gold encapsulation" or "solid solution," hindering the contact between the cyanide solution and the gold, resulting in extremely low direct leaching rates. Third, during the leaching process, the oxidation of sulfides forms a dense passivation film (such as sulfur film) on the surface of the gold particles. 0 This further hinders the dissolution of gold.

[0003] To address the aforementioned issues, industrial processes typically employ pretreatment methods such as oxidative roasting, bio-oxidation, and pressure oxidation to break down the structure of sulfide minerals and expose the encapsulated gold. However, these methods suffer from several drawbacks: oxidative roasting generates harmful gases like SO2, causing severe environmental pollution; bio-oxidation is time-consuming and inefficient; and pressure oxidation places high demands on equipment materials, resulting in substantial investment and operating costs. Therefore, developing a mild, efficient, and environmentally friendly integrated chemical desulfurization pretreatment and leaching technology has significant industrial value.

[0004] Chemical oxidative desulfurization under alkaline conditions is a promising alternative. Sodium cyanide (NaCN) itself has a certain oxidative dissolution effect on sulfide ores under alkaline conditions, but its reaction rate is slow, sulfur oxidation is incomplete, and an elemental sulfur passivation layer is easily formed on the mineral surface. Furthermore, the use of high-concentration cyanide poses significant environmental and safety risks. Although some studies have attempted to use other oxidants (such as potassium permanganate, peroxides, and copper-ammonia complexes) in synergy with cyanide, the results are often unsatisfactory, or the introduction of impurity ions interferes with subsequent gold leaching and recovery.

[0005] Recent studies have found that potassium ferricyanide (K3[Fe(CN)6]), commonly known as hematite, is a mild oxidizing agent that can selectively oxidize sulfides (S under alkaline conditions) 2- ) oxidized into higher oxidation states of sulfides (such as SO3) 2- SO4 2-The sulfur dioxide is reduced to potassium ferrocyanide (K4[Fe(CN)6], commonly known as potassium ferrocyanide). Ferrocyanide can then be re-oxidized back to ferrocyanide in the presence of oxygen in the air, theoretically forming a cyclical redox system. However, in practical applications, the desulfurization rate and depth of this system are still insufficient, and its effect on inhibiting the formation of sulfur films is limited. Summary of the Invention

[0006] In view of the technical problems existing in the background art, this application provides an alkaline desulfurization and cyanide leaching gold reagent system for sulfide ores. The core of this system is to construct a unique ternary reagent system composed of potassium ferrocyanide, low-concentration sodium cyanide and thioguanine nucleoside. The three components produce a synergistic effect, realizing efficient desulfurization of sulfide ores and gold extraction, and forming an efficient chemical cycle, achieving a high recovery rate of gold extraction from refractory sulfide ores.

[0007] This application provides an alkaline desulfurization and cyanidation gold leaching agent system for sulfide ores, comprising a main cyanidating agent and an auxiliary desulfurizing agent; the main cyanidating agent is sodium cyanide; the auxiliary desulfurizing agent is a composite agent composed of potassium ferrocyanide and thioguanine nucleoside.

[0008] Furthermore, in the auxiliary desulfurization agent, the mass ratio of potassium ferricyanide to thioguanine nucleoside is (5~10):1.

[0009] This application also provides a method for extracting gold using the aforementioned alkaline desulfurization and cyanide leaching gold extraction reagent system for sulfide ores, comprising the following steps:

[0010] S1, grinding low-grade, high-sulfur gold ore to obtain slurry;

[0011] S2, adjust the pH of the slurry to pH ≥10; first add the auxiliary desulfurization agent potassium ferricyanide and the compound agent composed of thioguanine nucleoside, stir at room temperature for 1-3 hours, then add the main cyanidation agent sodium cyanide, stir, and obtain the gold-containing solution and solid residue.

[0012] Further, in step S2, the amount of sodium cyanide used is 100~300 g / T, the amount of potassium ferrocyanide used is 50~300 g / T, and the amount of thioguanine nucleoside used is 10~40 g / T.

[0013] Further, in step S2, in the composite agent composed of potassium ferricyanide and thioguanine nucleoside, the mass ratio of potassium ferricyanide to thioguanine nucleoside is (5~10):1.

[0014] Furthermore, in the aforementioned low-grade, high-sulfur gold ore, the gold grade is 0.60 g / t, and the mass of sulfide minerals accounts for 10-20% of the total ore mass.

[0015] Furthermore, during the grinding process, the low-grade, high-sulfur gold ore is crushed to a particle size of -0.074 mm, with the ore powder accounting for 75% to 85% of the total mass of the material. Water is added to adjust the slurry to a mass percentage concentration of 30% to 35%.

[0016] Furthermore, the pH value of the slurry is adjusted by adding a pH adjuster; the pH adjuster is calcium oxide.

[0017] The beneficial effects of this application are as follows:

[0018] This application proposes an alkaline desulfurization and cyanide leaching reagent system for sulfide ores. This system comprises a main cyaniding agent and an auxiliary desulfurization agent. The main cyaniding agent is sodium cyanide, and the auxiliary desulfurization agent is a composite agent composed of potassium ferricyanide and thioguanine nucleoside. A synergistic effect is achieved among potassium ferricyanide, low-concentration sodium cyanide, and thioguanine nucleoside, resulting in highly efficient desulfurization of sulfide ores and gold extraction, forming a highly efficient chemical cycle.

[0019] Specifically, potassium ferricyanide and thioguanine nucleoside form a highly efficient "oxidation-inhibition" synergistic system. Potassium ferricyanide, as the primary oxidant, plays a crucial role in selectively attacking the sulfide mineral lattice, thus reducing S... 2- Directed oxidation produces soluble sulfonates and other products, efficiently dissociating the mineral structure and exposing gold, while avoiding the exposure of elemental sulfur (S). 0 The large-scale formation of sulfur atoms is observed. However, in actual complex mineral phase reactions, a small amount of reactive sulfur atoms inevitably escapes or undergoes local peroxidation. The thiol group (-SH) and electron-rich heterocycle in the molecular structure of thioguanine nucleosides can extremely sensitively capture these newly formed, highly reactive sulfur atoms. 0 The atoms "solidify" and "remove" the sulfur by rapidly forming stable organic sulfur compounds, thereby preventing the formation of a sulfur film and completely eliminating the threat of the passivation layer to the gold particles.

[0020] Furthermore, the synergy between potassium ferricyanide and thioguanine nucleoside goes far beyond simple functional complementarity, extending to mutual promotion at the cyanide leaching kinetics level, forming a positive feedback enhancement cycle.

[0021] Specifically, thioguanine nucleoside is not only a passive sulfur scavenger, but also a highly efficient electron transport medium, bridging the gap between potassium ferricyanide and the sulfide mineral surface. This significantly accelerates the rate at which potassium ferricyanide extracts electrons from the sulfide, thereby greatly enhancing the overall desulfurization reaction kinetics. The increased reaction rate means more gold is exposed per unit time, and potassium ferricyanide is reduced to potassium ferrocyanide more quickly. This reduction product, potassium ferrocyanide, is then regenerated back to potassium ferricyanide through electron transport, making the entire ferricyanide / ferrocyanide catalytic cycle faster and more efficient, maximizing reagent utilization.

[0022] Ultimately, this deep synergistic effect couples desulfurization and gold leaching, achieving a perfect unity of "cell wall breaking" and "obstacle removal." The rapid and selective oxidation of potassium ferricyanide proceeds smoothly under the synergistic effect of thioguanine nucleoside, resulting in thorough mineral decomposition while maintaining high surface activity. Simultaneously, the presence of thioguanine nucleoside can more specifically eliminate the risk of localized micro-area passivation and catalyze electron transfer. These two factors complement each other, ensuring that subsequent low-concentration sodium cyanide can efficiently leach the exposed gold without hindrance. Ultimately, this achieves high gold recovery rates from refractory sulfide ores while reducing total reagent consumption and environmental pollution.

[0023] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0025] Figure 1 This is a reflected light microscope image of the low-grade, high-sulfur gold ore (originating from a gold mine in a mining area in Inner Mongolia) used in this invention.

[0026] Figure 2 This is a surface distribution map of gold, copper, and iron elements in a low-grade, high-sulfur gold ore as described in this invention.

[0027] Figure 3 These are reflective microscope images of the sulfide encapsulation process in Example 1, where (a) is before dissociation and (b) is after dissociation.

[0028] Figure 4The image shows a reflection microscope image of the sulfide minerals in the ultraviolet wavelength range of 356–365 nm, as shown in Comparative Example 4.

[0029] Figure 5 The image shows a reflection microscope image of the sulfide minerals in Comparative Example 9 in the ultraviolet wavelength range of 356–365 nm. Detailed Implementation

[0030] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] This application provides an alkaline desulfurization and cyanidation gold leaching agent system for sulfide ores, comprising a main cyanidating agent and an auxiliary desulfurizing agent; the main cyanidating agent is sodium cyanide; the auxiliary desulfurizing agent is a composite agent composed of potassium ferrocyanide and thioguanine nucleoside.

[0033] In the auxiliary desulfurization agent, the mass ratio of potassium ferricyanide to thioguanine nucleoside is (5~10):1.

[0034] This application also provides a method for extracting gold using the aforementioned alkaline desulfurization and cyanide leaching gold extraction reagent system for sulfide ores, comprising the following steps:

[0035] S1, grinding low-grade, high-sulfur gold ore to obtain slurry;

[0036] In low-grade, high-sulfur gold ore, the gold grade is 0.60 g / t, and the mass of sulfide minerals accounts for 10-20% of the total ore mass.

[0037] During the grinding process, the low-grade, high-sulfur gold ore is crushed to a particle size of -0.074mm, with the ore powder accounting for 75% to 85% of the total mass of the material. Water is added to adjust the slurry to a mass percentage concentration of 30% to 35%.

[0038] S2, adjust the pH of the slurry to pH ≥10; first add the auxiliary desulfurization agent potassium ferricyanide and the compound agent composed of thioguanine nucleoside, stir at room temperature for 1-3 hours, then add the main cyanidation agent sodium cyanide, stir, and obtain the gold-containing solution and solid residue.

[0039] The method for adjusting the pH value of the slurry is to add calcium oxide as a pH adjuster.

[0040] In the compound agent composed of potassium ferricyanide and thioguanine nucleoside, the mass ratio of potassium ferricyanide to thioguanine nucleoside is (5~10):1.

[0041] The mineral weight of sodium cyanide is 100~300g / T, the mineral weight of potassium ferrocyanide is 50~300g / T, and the mineral weight of thioguanine nucleoside is 10~40g / T.

[0042] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0043] Example 1

[0044] The low-grade, high-sulfur gold ore in this embodiment comes from a gold mine in a mining area in Inner Mongolia. The gold grade is 0.60 g / t, and the mass of sulfide minerals accounts for 10-20% of the total ore mass.

[0045] A reflective microscope image of this low-grade, high-sulfur gold ore is shown below. Figure 1 As shown.

[0046] The surface distribution diagrams of gold, copper, and iron elements in this low-grade, high-sulfur gold deposit are as follows: Figure 2 As shown.

[0047] This embodiment provides a method for extracting gold from sulfide ore using an alkaline desulfurization and cyanide leaching reagent system, comprising the following steps:

[0048] S1, low-grade high-sulfur gold ore is crushed to a particle size of -0.074mm, with the ore powder accounting for 80% of the total mass of the material, and water is added to adjust the slurry to a mass percentage concentration of 35%.

[0049] S2, the pH of the slurry prepared in step S1 is adjusted to 10.5 using calcium oxide. Then, an auxiliary desulfurization agent (a composite agent of potassium ferricyanide and thioguanine nucleoside) is added; the mass ratio of potassium ferricyanide to thioguanine nucleoside in the auxiliary desulfurization agent is 7:1, with a potassium ferricyanide ore content of 70 g / T and a thioguanine nucleoside ore content of 10 g / T. The mixture is stirred at room temperature for 2 hours, followed by the addition of the main cyaniding agent (sodium cyanide), with a sodium cyanide ore content of 200 g / T. Leaching is then carried out at room temperature with stirring for 12 hours. Solid-liquid separation is performed to obtain a precious metal-bearing solution and a solid residue (leaching tailings).

[0050] The gold concentration in the precious metal solution was tested using an ICP-OES analyzer. The gold content in the leaching residue was tested using the fire assay method, and the analytical method was in accordance with GB / T 7739.

[0051] Specifically, the gold content in solid residues is tested using the fire assay method, and the testing and analysis methods refer to GB / T7739.

[0052] Calculate the gold leaching rate to determine the extent of gold leaching.

[0053] ;

[0054] In the formula, η represents the gold leaching rate, in %; m1 represents the mass of the original low-grade high-sulfur gold ore, in g; β1 represents the grade of the original low-grade high-sulfur gold ore, in g / t; m2 represents the mass of the solid residue after leaching of the low-grade high-sulfur gold ore, in g; and β2 represents the grade of the solid residue after leaching, in g / t.

[0055] The gold-containing precious liquor was tested by ICP-OES. The gold concentration in the precious liquor was used to further prove the gold leaching rate obtained by the method of this application. It can be seen that the error of the above two methods is less than 1%, indicating that the test value of this method is valid data.

[0056] Comparative Example 1

[0057] Compared with Example 1, the difference is that no auxiliary desulfurization agent was added in step S2, and the amount of sodium cyanide ore used was 5000g / T (the amount of sodium cyanide used follows the recommended amount of reagent in the industrial feasibility assessment report). The rest is roughly the same as Example 1, and will not be repeated here.

[0058] Comparative Example 2

[0059] Compared with Example 1, the difference is that no auxiliary desulfurization agent was added in step S2. Otherwise, it is roughly the same as Example 1 and will not be described again here.

[0060] Comparative Example 3

[0061] The difference between Example 1 and Example 2 is that the potassium ferricyanide component in the auxiliary desulfurization agent was not added in step S2. Everything else is largely the same as in Example 1 and will not be repeated here.

[0062] Comparative Example 4

[0063] The difference from Example 1 is that the thioguanine nucleoside component in the auxiliary desulfurization agent was not added in step S2. Everything else is largely the same as in Example 1 and will not be repeated here.

[0064] Comparative Example 5

[0065] The difference from Example 1 is that the main cyaniding agent (sodium cyanide) was not added in step S2. Everything else is largely the same as in Example 1 and will not be repeated here.

[0066] The gold leaching rates of Example 1 and Comparative Examples 1-5 are shown in Table 1.

[0067] Table 1. Gold leaching effects of Example 1 and Comparative Examples 1-5

[0068]

[0069] As shown in Table 1, potassium ferricyanide, thioguanine nucleoside, and sodium cyanide form an indispensable organic whole and are key to efficient gold extraction.

[0070] Figure 3 This is a reflective microscope image of the sulfide encapsulation process in Example 1. It can be clearly seen that the originally dense sulfide minerals undergo chemical dissociation under the action of the "potassium ferrocyanide-thioguanine nucleoside" composite desulfurization agent. The agent reacts with the sulfide minerals to form pulverized ring-shaped bands, while simultaneously exhibiting a tendency for core dissolution.

[0071] In Comparative Example 3, when potassium ferricyanide was missing from the auxiliary desulfurization agent, the gold leaching rate plummeted from 92% to 14%; in Comparative Example 4, when thioguanine nucleoside was missing from the auxiliary desulfurization agent, the gold leaching rate plummeted from 92% to 21%. This indicates that the "potassium ferricyanide-thioguanine nucleoside" composite auxiliary desulfurization agent is indispensable, and the two work synergistically to effectively overcome the hindrance of sulfides to gold leaching.

[0072] Figure 4 The image shows a reflected light microscope image of the sulfide minerals in Comparative Example 4 in the ultraviolet wavelength range of 356–365 nm. It can be seen that without the introduction of thioguanine nucleosides, partially dissolved sulfide minerals form new inclusions, hindering subsequent gold leaching.

[0073] Compare Figure 3 and Figure 4 It is known that thioguanine nucleosides can rapidly form stable organic sulfur compounds that "solidify" and "remove" sulfide minerals, thereby preventing the formation of sulfur films and completely eliminating the passivation layer's effect on gold particles.

[0074] In Comparative Example 5, the gold leaching rate was 0 when sodium cyanide, the main cyaniding agent, was not used. This indicates that sodium cyanide is indispensable as the main agent for gold leaching; without sodium cyanide, the gold leaching process cannot proceed.

[0075] Furthermore, as shown in Table 1, in Example 1, a high leaching rate of 92% can be achieved with only a very low amount of sodium cyanide (200 g / T). Conversely, if the auxiliary desulfurization agent is missing (Comparative Example 1), the cost of a 25-fold increase in sodium cyanide dosage (5000 g / T) and a lower leaching rate (75%) must be paid. This demonstrates that potassium ferrocyanide, thioguanine nucleoside, and sodium cyanide work synergistically to maximize both economy and efficiency.

[0076] Examples 2-8 and Comparative Examples 6-13

[0077] Examples 2-8 and Comparative Examples 6-13 provide a method for extracting gold from sulfide ore using an alkaline desulfurization and cyanidation gold leaching reagent system. The difference between this method and Example 1 is that the amounts of potassium ferricyanide and thioguanine nucleoside in the auxiliary desulfurization reagent are different, as shown in Table 2. Other experimental parameters and conditions are basically the same as in Example 1 and will not be repeated here.

[0078] Table 2. Dosage of each component and gold leaching rate in the pharmaceutical preparations of Examples 2-8 and Comparative Examples 6-13

[0079]

[0080] As shown in Table 2, the ratio of potassium ferricyanide to thioguanine nucleoside has a significant impact on the gold leaching rate. The two need to be maintained within a suitable ratio range to achieve the best synergistic desulfurization and gold leaching effect.

[0081] When the dosage of potassium ferricyanide is in the range of 50-300 g / T and the dosage of thioguanine nucleoside is in the range of 10-40 g / T (Examples 1-8), the gold leaching rate remains stable at a high level of 91% to 95%. This indicates that within this range, potassium ferricyanide can provide sufficient and moderate oxidizing power to effectively destroy the structure of sulfide minerals, while sufficient thioguanine nucleoside can promptly remove any active sulfur atoms that may be generated during the reaction, preventing them from polymerizing into a passivation film. Furthermore, the two promote each other, accelerating the reaction kinetics and the recycling of reagents.

[0082] However, an imbalance in the ratio of the two reagents, whether excessive or insufficient in either, severely disrupts the synergistic effect of the system, leading to a sharp decline in leaching rate. Specifically, when the amount of potassium ferricyanide is insufficient (comparative example 6, 40 g / T), its oxidizing capacity is insufficient to completely dissociate the sulfide ore, resulting in some gold remaining unexposed and the leaching rate dropping to 81%. More critically, when the amount of thioguanine nucleoside is too high (comparative examples 7-9, 50 g / T), even when the amount of potassium ferricyanide is within the effective range of 100-300 g / T, the leaching rate still shows a significant decrease. This is most likely because excessive thioguanine nucleoside, due to its strong adsorption and complexing ability, not only captures sulfur atoms but may also be over-adsorbed onto the surface of the mineral or exposed gold, forming a new organic barrier layer that hinders the leaching of gold by sodium cyanide, leading to a negative effect.

[0083] Figure 5 The image shows a reflection microscope image of the sulfide minerals in Comparative Example 9 in the ultraviolet wavelength range of 356–365 nm.

[0084] Under ultraviolet light excitation at wavelengths of 356–365 nm, thioguanine nucleosides exhibit characteristic fluorescence due to their unique conjugated cyclic structure. Observation of Comparative Example 9 within the ultraviolet wavelength range of 356–365 nm using a reflective microscope reveals the formation of an organic barrier layer on the mineral surface, further confirming the above findings.

[0085] Experiments show that when the dosage of potassium ferricyanide is too high and exceeds the optimal range (comparative example 10-13, 350-400 g / T), it will also have an adverse effect on the system. An excessively strong oxidizing environment may exacerbate side reactions, such as over-oxidizing sulfides to generate more sulfate, or causing non-selective reactions with other components in the slurry, resulting in unnecessary reagent loss, and may even interfere with the structure or function of thioguanine nucleosides. In this case, even with the addition of 10-40 g / T of thioguanine nucleosides, the decline in leaching rate (from 83% to 63%) could not be reversed. This demonstrates that there is a strict, non-linear synergistic window between the two; any excess of any single reagent will disrupt the chemical equilibrium of the system, ultimately leading to gold leaching failure.

[0086] Examples 9-13 and Comparative Examples 14-17

[0087] Examples 9-13 and Comparative Examples 14-17 provide a method for extracting gold from sulfide ore using an alkaline desulfurization and cyanidation gold leaching reagent system. The difference from Example 1 is that the amounts of potassium ferrocyanide, thioguanine nucleoside, and sodium cyanide are different, as shown in Table 3. Other experimental parameters and conditions are basically the same as in Example 1 and will not be repeated here.

[0088] Table 3. Dosage of each component and gold leaching rate in the pharmaceutical preparations of Examples 9-13 and Comparative Examples 14-17

[0089]

[0090] As shown in Table 3, the amount of sodium cyanide has a threshold effect and an economically optimal range on the gold leaching rate, rather than a simple linear relationship. Under the premise that the synergistic desulfurization system composed of potassium ferricyanide and thioguanine nucleoside is operating effectively, the amount of sodium cyanide can maintain a very high gold leaching rate (90%~95%) within a wide range (100-300 g / T).

[0091] Specifically, when the sodium cyanide dosage was increased from 90 g / T (Comparative Example 14) to 100 g / T (Example 9), the gold leaching rate showed a significant jump (from 85% to 90%), indicating that 100 g / T is the next critical effective concentration threshold for this system. Below this value, the total amount of cyanide ions used for gold complexation and sulfur film removal is insufficient, leading to a decline in the leaching rate. However, once this threshold is exceeded, further increasing the sodium cyanide dosage (e.g., from 100 g / T to 400 g / T) does not significantly improve the leaching rate (Examples 9, 10, and Comparative Examples 15-17 all maintained a high plateau of 90%-94%). This demonstrates that in this ternary synergistic system, the efficient cell disruption of potassium ferricyanide and the perfect inactivation of thioguanine nucleosides greatly reduce the dependence on the amount of sodium cyanide. While adding excessive sodium cyanide (e.g., 400 g / T) has no negative impact on the leaching rate, it is unnecessary from both an economic and environmental perspective.

[0092] In summary, the reagent system of this application, through the precise synergy of potassium ferricyanide and thioguanine nucleoside, successfully optimized and stabilized the dosage of sodium cyanide from the high level of conventional dosage (usually much higher than 200 g / T) to a relatively low economic range (100-300 g / T), significantly reducing reagent costs and environmental risks while ensuring extremely high gold recovery rates.

[0093] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A basic desulfurization and cyanidation gold leaching agent system for sulfide ores, characterized in that, The alkaline desulfurization and cyanidation gold leaching agent system for sulfide ores includes a main cyanidating agent and an auxiliary desulfurizing agent; the main cyanidating agent is sodium cyanide; the auxiliary desulfurizing agent is a composite agent composed of potassium ferricyanide and thioguanine nucleoside; wherein the mass ratio of potassium ferricyanide to thioguanine nucleoside is (5~10):1; the amount of sodium cyanide used is 100~300 g / T based on the ore mass, the amount of potassium ferricyanide used is 50~300 g / T based on the ore mass, and the amount of thioguanine nucleoside used is 10~40 g / T based on the ore mass.

2. A method for extracting gold from sulfide ores using an alkaline desulfurization and cyanidation gold leaching reagent system, characterized in that, The alkaline desulfurization and cyanide leaching reagent system for sulfide ores as described in claim 1 includes the following steps: S1, grinding low-grade, high-sulfur gold ore to obtain slurry; S2, adjust the pH of the slurry to pH ≥10; first add the auxiliary desulfurization agent potassium ferricyanide and the compound agent composed of thioguanine nucleoside, stir at room temperature for 1-3 hours, then add the main cyanidation agent sodium cyanide, stir, and obtain the gold-containing solution and solid residue.

3. The method for extracting gold from sulfide ore using the alkaline desulfurization and cyanidation gold leaching reagent system according to claim 2, characterized in that, In the aforementioned low-grade, high-sulfur gold ore, the gold grade is 0.60 g / t, and the mass of sulfide minerals accounts for 10-20% of the total ore mass.

4. The method for extracting gold from sulfide ore using the alkaline desulfurization and cyanidation gold leaching reagent system according to claim 2, characterized in that, During the grinding process, the low-grade, high-sulfur gold ore is crushed to a particle size of -0.074mm, with the mineral powder accounting for 75% to 85% of the total mass of the material. Water is added to adjust the slurry to a mass percentage concentration of 30% to 35%.

5. The method for extracting gold using the alkaline desulfurization and cyanidation gold leaching reagent system for sulfide ores according to claim 2, characterized in that, The pH value of the slurry is adjusted by adding a pH adjuster; the pH adjuster is calcium oxide.

Images