Gold leaching reagent system and heap leaching process for treating low-grade gold ores

Abstract

This application provides a gold leaching reagent system and its heap leaching process for treating low-grade gold ore, belonging to the field of hydrometallurgy. The gold leaching reagent system includes a main leaching agent, a catalytic leaching agent, and a stabilizer; wherein the main leaching agent is glycine, the catalytic leaching agent is anhydrous sodium thiosulfate, and the stabilizer is an organic ammonium salt. This application constructs a ternary stable and synergistic system of sodium thiosulfate-glycine-organic ammonium salt by introducing an organic ammonium salt with a specific structure. This optimizes the traditional thiosulfate gold leaching process from both thermodynamic and kinetic perspectives. The organic ammonium salt cations can dynamically adsorb around the thiosulfate ions in solution through intermolecular interactions, forming an effective shielding layer. This significantly inhibits the side reaction of sodium thiosulfate being oxidized and decomposed into sulfate and other ineffective products by dissolved oxygen, maintaining the long-term stability of the effective components in the leachate. This gold leaching reagent system has comprehensive advantages such as high leaching efficiency, good reagent stability, environmental friendliness, and low operating costs.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, specifically to a gold leaching reagent system and its heap leaching process for treating low-grade gold ore. Background Technology

[0002] Currently, the main method for large-scale industrial extraction of gold from ores is cyanidation. This method relies on the formation of stable complexes between cyanide ions and gold to achieve leaching. Although the technology is mature, it poses environmental risks. Therefore, developing efficient, low-toxicity, and economical non-cyanide gold leaching technologies has become an urgent technological development direction for the industry.

[0003] Among numerous non-cyanide leaching reagents, sodium thiosulfate and amino acid systems have shown significant potential. Sodium thiosulfate gold leaching systems offer advantages such as non-toxicity, rapid leaching rates, and high tolerance to certain impurities. However, their main drawback lies in poor chemical stability. In alkaline aerobic environments, thiosulfate ions readily undergo disproportionation or oxidative decomposition, generating byproducts such as polythionates, sulfides, and sulfates. This leads to significant consumption of effective reagents, increased costs, and potential surface passivation, severely restricting its industrial application, especially in heap leaching processes requiring long-term cycles. Glycine, as an environmentally friendly natural amino acid, can form stable complexes with gold in alkaline solutions, resulting in a clean process. However, its use alone often faces challenges such as slow leaching kinetics, high required alkalinity, and limited adaptability to different ore types. Existing technologies mostly focus on single reagents or simple physical mixtures, failing to fundamentally solve the problem of synergistically improving reagent stability and leaching efficiency.

[0004] In view of this, it is necessary to design a gold leaching reagent system and a heap leaching process for treating low-grade gold ore to solve the above problems. Summary of the Invention

[0005] In view of the technical problems existing in the background art, this application provides a gold leaching reagent system and a heap leaching process for treating low-grade gold ore, aiming to solve the technical problems of poor chemical stability and high reagent consumption of the existing sodium thiosulfate system and slow leaching kinetics and limited adaptability of the glycine system.

[0006] In a first aspect, this application provides a gold leaching agent system, comprising a gold leaching main agent, a catalytic leaching agent, and a stabilizer; the gold leaching main agent is glycine; the catalytic leaching agent is anhydrous sodium thiosulfate; and the stabilizer is an organic ammonium salt with the following molecular structural formula: .

[0007] As a further improvement of this application, in the gold leaching agent system, the mass concentration of the gold leaching agent is 25~50 g / L; the mass concentration of the catalytic leaching agent is 47.5~95 g / L; and the mass concentration of the stabilizer is 1~2 g / L.

[0008] Secondly, this application provides a heap leaching process for processing low-grade gold ore, which uses the gold leaching reagent system described in the first aspect to extract gold from low-grade gold ore, including the following steps: S1. The gold-bearing mineral material is crushed to obtain a crushed sample, and the crushed sample is added to a heap leaching column to obtain heap leaching material; S2. Mix the gold leaching agent, catalytic leaching agent and stabilizer evenly, and adjust the pH value to 8.5~9.5 to obtain the gold leaching agent system; S3. The gold leaching agent system is added from the top of the heap leaching column, and the heap leaching ore is circulated and washed to obtain gold-bearing precious solution and leaching ore tailings; S4. The gold content in the leaching mineral tailings is determined by fire assay, and the leaching rate is calculated.

[0009] As a further improvement of this application, in step S1, the ore with a particle size ≤10cm accounts for 70~75% of the total mass of the crushed sample.

[0010] As a further improvement of this application, in step S3, the intensity of the cyclic rinsing is 7~13 L / m. 2 ·h.

[0011] As a further improvement to this application, the cyclic rinsing time is 42 to 75 days.

[0012] As a further improvement to this application, the gold-bearing mineral material includes one or more of the following: oxidized heap leaching residue, low-grade roasted sand, and low-grade gold ore.

[0013] The beneficial effects of this application are as follows: This application provides a gold leaching reagent system and its heap leaching process for treating low-grade gold ore. The gold leaching reagent system includes a gold leaching agent, a catalytic leaching agent, and a stabilizer; wherein the gold leaching agent is glycine, the catalytic leaching agent is anhydrous sodium thiosulfate, and the stabilizer is an organic ammonium salt. This application constructs a ternary stable and synergistic system of sodium thiosulfate-glycine-organic ammonium salt by introducing an organic ammonium salt with a specific structure, thus optimizing the traditional thiosulfate gold leaching process from both thermodynamic and kinetic perspectives. This system is particularly suitable for heap leaching of low-grade gold ore, and can operate over a wide range of pH (8.5-9.5) and injection flow rates (7-13 L / m³). 2 Within the range of h), the gold leaching rate is not less than 65%, while the ineffective consumption rate of sodium thiosulfate is significantly reduced to below 22%, which has the comprehensive advantages of high leaching efficiency, good reagent stability, environmental friendliness and low operating cost.

[0014] The organic ammonium salt cations introduced in this system dynamically adsorb around thiosulfate ions in solution through their unique electronic effects, forming a weakly interacting shielding layer. This shielding layer effectively blocks the direct attack of dissolved oxygen on thiosulfate ions, significantly inhibiting their oxidative decomposition pathways to ineffective or harmful products such as sulfate and tetrathiosulfate ions. This maintains the sodium thiosulfate concentration in the leaching system at a stable kinetic plateau, ensuring a continuous supply of thiosulfate ions as a gold oxidation catalyst. This overcomes the fundamental problems of leaching rate fluctuations and excessive reagent consumption caused by rapid degradation of the main agent in traditional processes.

[0015] 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

[0016] 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.

[0017] Figure 1 This is a color illustration of the original mineral distribution in Example 1 of this application; Figure 2 The 1H NMR spectrum of the organic ammonium salt stabilizer prepared in Example 18 of this application; Figure 3 The image shows the XRD pattern of the leaching tailings in Comparative Example 7. Detailed Implementation

[0018] 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.

[0019] 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.

[0020] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0023] Existing technologies in the field of non-cyanide gold extraction mainly use sodium thiosulfate and amino acid systems. However, the sodium thiosulfate system has poor chemical stability and is easy to decompose, resulting in high reagent consumption and easy to cause surface passivation. The glycine system has problems with slow leaching kinetics and limited adaptability, making it difficult to meet the urgent need for long-term reagent stability and synergistic improvement of leaching efficiency in complex scenarios such as heap leaching of low-grade ores.

[0024] To address the technical problems of poor chemical stability and high reagent consumption in existing sodium thiosulfate systems, and slow leaching kinetics and limited adaptability in glycine systems, this application provides a gold leaching reagent system and its heap leaching process for treating low-grade gold ores. By coupling specific functionalized organic ammonium salts with sodium thiosulfate and glycine through molecular design and process, the chemical stability of sodium thiosulfate in alkaline environments can be significantly improved, reagent consumption can be greatly reduced, and the gold leaching kinetic rate can be accelerated, achieving the technical effect of efficient, low-cost, and environmentally friendly long-term heap leaching extraction of low-grade gold ores.

[0025] In a first aspect, embodiments of this application provide a gold leaching agent system, comprising a gold leaching main agent, a catalytic leaching agent, and a stabilizer; the gold leaching main agent is glycine; the catalytic leaching agent is anhydrous sodium thiosulfate; and the stabilizer is an organic ammonium salt, the molecular structural formula of which is: .

[0026] In the technical solution of this application embodiment, organic ammonium salt cations can dynamically adsorb around thiosulfate ions in solution through intermolecular interactions, forming an effective shielding layer. This significantly inhibits the side reaction of sodium thiosulfate being oxidized and decomposed into sulfates and other ineffective products by dissolved oxygen, thereby maintaining the long-term stability of the effective components in the leachate. During the leaching process, monovalent gold ions (Au) generated under the catalysis of sodium thiosulfate... + It will simultaneously react with thiosulfate ions (S2O3) in the system. 2- ) and glycine anion (Gly - Competition for coordination occurs. The presence of the organic ammonium salt stabilizes the thiosulfate concentration, leading to the initial formation of the metastable gold thiosulfate complex (Au(S₂O₃)₂). 3- The gold content is maintained at an appropriate level. Glycine, as a stronger bidentate ligand, and its thermodynamically more stable glycine-gold (Au(Gly)2) complex, have gradually become the dominant products. This ligand substitution process drives the gold dissolution equilibrium to shift continuously to the right, while avoiding the formation of sulfide passivation films that may be caused by excessive accumulation of gold thiosulfate. This achieves efficient and selective leaching of gold and long-term stability of the solution chemical environment, forming a highly efficient synergistic mechanism of catalytic oxidation, stable coordination, and directional substitution.

[0027] Furthermore, in some embodiments, in the gold leaching agent system, the mass concentration of the gold leaching agent is 25~50 g / L; the mass concentration of the catalytic leaching agent is 47.5~95 g / L; and the mass concentration of the stabilizer is 1~2 g / L.

[0028] In the technical solution of this application embodiment, a composite gold leaching environment with stable chemical properties, fast kinetic rate and controllable reagent consumption is constructed through specific concentration synergy, which is particularly suitable for heap leaching processes of low-grade ores with long processing cycles and complex environments.

[0029] Secondly, embodiments of this application provide a heap leaching process for processing low-grade gold ore, employing the aforementioned gold leaching reagent system to extract gold from low-grade gold ore, comprising the following steps: S1. The gold-bearing ore is crushed to obtain a crushed sample. The crushed sample is then added to a heap leaching column to obtain heap leaching material. In the crushed sample, ore particles with a size ≤10cm account for 70-75% of the total mass of the material. S2. Mix the gold leaching agent, catalytic leaching agent and stabilizer evenly, and adjust the pH value to 8.5~9.5 to obtain the gold leaching agent system; S3. The gold leaching reagent system is added from the top of the heap leaching column, and the heap leaching ore is circulated and washed to obtain gold-bearing precious solution and leaching ore tailings; S4. The gold content in the mineral leaching tailings was determined by fire assay, and the leaching rate was calculated.

[0030] in, ; In the formula, η represents the leaching rate of gold; m1 represents the mass of the original leaching sample; β1 represents the grade of the original leaching sample; m2 represents the mass of the residue after leaching; β2 represents the grade of the residue after leaching.

[0031] In the technical solution of this application embodiment, by crushing the mineral material to a specific particle size and using the above-mentioned gold leaching agent system, the gold leaching efficiency is significantly improved; by circulating rinsing to ensure sufficient contact between the agent and the mineral material, the leaching rate is further improved. The gold content in the tailings is tested using the fire assay method, specifically, the testing and analysis method refers to GB / T 7739. The gold-bearing precious solution is detected by ICP-OES (inductively coupled plasma optical emission spectroscopy), and the calculated gold leaching rate is further verified based on the gold concentration in the gold-bearing precious solution. The relative error between the two methods is less than 1% to be considered valid data. By cross-validating two different detection methods, the accuracy of the data is improved.

[0032] Furthermore, in some embodiments, in step S3, the intensity of the cyclic rinsing is 7~13 L / m. 2 •h; the cyclic rinsing time is 42~75 days.

[0033] In the technical solution of this application embodiment, rinsing is performed from top to bottom at normal temperature and pressure, and the injection flow rate is controlled to be 7~13L / m. 2 •h, reduces ineffective decomposition of reagents and promotes uniform penetration. The leaching solution is collected at the bottom and circulated to the top of the heap leaching column by a pump. The circulation rinsing lasts for 42 to 75 days, which helps to fully leach the target metal.

[0034] Furthermore, in some embodiments, the gold-bearing mineral material includes one or more of the following: oxidized heap leaching residue, low-grade roasted sand, and low-grade gold ore.

[0035] In the technical solution of this application embodiment, the unique chemical properties of the gold leaching agent system enable efficient leaching of difficult-to-process low-grade resources. This has important practical significance and technical value for promoting the industrial application of non-cyanide gold extraction technology, especially heap leaching technology.

[0036] 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.

[0037] Example 1 This embodiment provides a heap leaching process for processing low-grade gold ore. The multi-element content of the gold-bearing ore used in the experiment is shown in Table 1, the relative content measurement results of the ore minerals are shown in Table 2, and the color map of the original mineral distribution is shown in the figure. Figure 1 As shown, the specific steps include: S1. The gold-bearing mineral material is crushed until the ore particle size ≤10cm accounts for 75% of the total mass of the material to obtain the crushed sample. The crushed sample is added into a heap leaching column with a height of 1m and an inner diameter of 100cm, and the stacking height is 0.8m to obtain the heap leaching material. S2. Glycine, anhydrous sodium thiosulfate, and an organic ammonium salt stabilizer are mixed evenly to prepare a 50L reagent solution. Sodium hydroxide is added to adjust the pH to 9.2 to obtain the gold leaching reagent system. The mass concentration of glycine is 25 g / L, the mass concentration of anhydrous sodium thiosulfate is 47.5 g / L, and the mass concentration of the organic ammonium salt stabilizer is 1 g / L. The structural formula of the organic ammonium salt stabilizer is: ; S3. Add the gold leaching reagent system from the top of the heap leaching column at a flow rate of 10 L / m. 2 •h, the heap leaching material is circulated and washed, the leaching liquid flowing out from the bottom is collected and circulated to the top of the heap leaching column by a pump, and the circulation and washing is carried out for 54 days to obtain gold-bearing solution and leaching mineral tailings; S4. The gold content in the mineral leaching tailings was determined by fire assay, and the leaching rate was calculated.

[0038] Table 1. Results of multi-element analysis of raw ore Table 2. Measurement results of relative mineral content in ores Examples 2-4 and Comparative Examples 1-3 Examples 2-4 and Comparative Examples 1-3 each provide a heap leaching process for processing low-grade gold ore. Compared with Example 1, the only difference is that the concentration of glycine is different in step S2. The rest is roughly the same as Example 1, and will not be repeated here.

[0039] To accurately monitor the concentration change of sodium thiosulfate, a key component, during the leaching process, iodometric titration was used. The test method is as follows: Take 5.0 mL of the leaching solution to be tested, add 4 drops of 10% starch indicator, and immediately titrate with a 0.1000 mol / L iodine standard titration solution. The endpoint is reached when the solution changes from colorless to blue and does not fade within 30 seconds. Record the volume of iodine standard solution consumed as V. This titration result corresponds to the total amount of sodium thiosulfate and sodium sulfite in the leaching solution. To eliminate the interference of sodium sulfite, take another 20.0 mL of the same leaching solution to be tested, add 2.0 g of solid magnesium sulfate, shake to fully dissolve and selectively precipitate and mask sulfite ions. After standing, take 5.0 mL of the supernatant, add 4 drops of starch indicator, and titrate with the same iodine standard solution to the blue endpoint. Record the volume consumed as V1. This result is the amount of iodine consumed by sodium thiosulfate alone, as shown in the following formula: W1 = (0.1 × V1 × 248.2) / 5; W2 = 0.1 × (V - V1) × 126 / 5; In the formula, W1 is the concentration of sodium thiosulfate, W2 is the concentration of sodium sulfite, and V1 and V are the volumes of iodine standard titration solution consumed in the titration. The change in sodium thiosulfate concentration (i.e., consumption) in the leaching system can be calculated using the following formula: ΔC 硫代硫酸钠 =C0-C t =0.1×(V 1,0 -V 1,t) ×248.25 / 5; Where: ΔC 硫代硫酸钠 This represents the concentration of sodium thiosulfate consumed within time t. A positive value indicates a decrease in concentration. C0 represents the concentration of sodium thiosulfate in the leachate at the start of leaching (t=0) or at a certain initial moment, expressed by the formula C0=0.1×V. 1,0 The result is calculated as ×248.2 / 5; C t The concentration of sodium thiosulfate in the leachate at time t during leaching is expressed by formula C. t =0.1×V 1,t The result is calculated as ×248.2 / 5; V 1,0 This represents the volume of iodine standard titration solution consumed by sodium thiosulfate in the sample at the initial titration time (or control blank). V 1,t The volume of iodine standard titration solution consumed in titrating sodium thiosulfate in a sample taken at time t; The consumption rate (η) of sodium thiosulfate can be calculated using the following formula and is a key indicator for evaluating reagent stability and leaching system efficiency: η=(C0-C t ) / C0×100%=(1-V 1,t / V 1,0 ) × 100%; η represents the consumption rate of sodium thiosulfate from the start of leaching to time t.

[0040] Table 3 Test results of Examples 1-4 and Comparative Examples 1-3 As shown in Table 3, the glycine-sodium thiosulfate-organic ammonium salt synergistic leaching system constructed in this application has a gold leaching rate of over 65%. In Comparative Example 1, when no glycine is added to the system, sodium thiosulfate exists as the only gold complexing agent and oxidizing medium, with a consumption rate as high as 32%, while the gold leaching rate is only 29%. This indicates that in the absence of competitive coordination by glycine anions, sodium thiosulfate is mainly consumed in large quantities due to chemical oxidation decomposition (such as being oxidized to sulfite by dissolved oxygen). At the same time, due to the lack of catalytic redox media such as copper ions, the oxidation-dissolution kinetics of sodium thiosulfate on gold is extremely slow, resulting in a large amount of decomposition but failing to effectively drive the gold leaching reaction. This highlights the inherent defects of the single thiosulfate system in terms of low efficiency and instability under catalyst-free conditions.

[0041] Examples 5-9 and Comparative Examples 4-6 Examples 5-9 and Comparative Examples 4-6 each provide a heap leaching process for processing low-grade gold ore. Compared with Example 1, the only difference is that the concentration of anhydrous sodium thiosulfate is different in step S2. The rest is roughly the same as Example 1, and will not be repeated here.

[0042] Table 4. Test results of Examples 5-9 and Comparative Examples 4-6 Table 4 shows that the gold leaching rate is significantly limited when anhydrous sodium thiosulfate is not added or its concentration is too low. This indicates that insufficient concentration of sodium thiosulfate, as a necessary catalytic oxidant for gold oxidation and dissolution, directly leads to a weak oxidation driving force, making it impossible to effectively convert elemental gold into complexable monovalent gold ions. Even with strong subsequent coordination ability of glycine, it is difficult to play a role. When the sodium thiosulfate concentration is too high, the gold leaching rate stabilizes at a high plateau of 74%, but the consumption rate of sodium thiosulfate increases.

[0043] Examples 10-11 and Comparative Examples 7-9 Examples 10-11 and Comparative Examples 7-9 each provide a heap leaching process for processing low-grade gold ore. Compared with Example 1, the only difference is that the concentration of the organic ammonium salt stabilizer is different in step S2. The rest is roughly the same as Example 1, and will not be repeated here.

[0044] Table 5. Test results of Examples 10-11 and Comparative Examples 7-9 As shown in Table 5, the specific organic ammonium salt introduced in this application plays a decisive role in the stability and efficiency of the entire leaching system. When the organic ammonium salt is not added to the system at all, the consumption rate of sodium thiosulfate is as high as 54%, while the gold leaching rate is only 56%. This indicates that in the absence of this stabilizer, most of the sodium thiosulfate is not used for effective gold leaching, but is rapidly consumed through ineffective pathways such as oxidative decomposition, leading to system instability and low efficiency. When the concentration of the organic ammonium salt is too high, neither the sodium thiosulfate consumption rate nor the gold leaching rate is further improved, indicating that its stabilizing effect has reached saturation, and excessive addition only increases costs without improving performance.

[0045] To clarify the decomposition pathway and mineral phase changes of sodium thiosulfate during leaching, the leaching tailings of Comparative Example 7 were analyzed: the slag after leaching was filtered and thoroughly washed with deionized water. The suspended fine particles generated during washing were collected, dried at 60℃, and ground into powder. X-ray diffraction (XRD) analysis was performed on the powder sample, as shown... Figure 3 As shown in the spectrum, the characteristic diffraction peaks of ferrous sulfite and sodium thiosulfate were clearly observed. This result indicates that sodium thiosulfate did indeed undergo oxidative decomposition in the leaching system, with ferrous sulfite being one of its final products. This directly confirms, at the phase level, the main chemical pathway for the ineffective consumption of sodium thiosulfate. Simultaneously, the appearance of the characteristic peak of ferrous sulfite indicates that some iron minerals in the ore underwent chemical reactions under alkaline leaching conditions.

[0046] Examples 12-15 and Comparative Examples 10-12 Examples 12-15 and Comparative Examples 10-12 respectively provide a heap leaching process for processing low-grade gold ore. Compared with Example 1, the only difference is that the pH value of the gold leaching agent system is different in step S2. The rest is roughly the same as Example 1, and will not be repeated here.

[0047] Table 6. Test results of Examples 12-15 and Comparative Examples 10-12 As shown in Table 6, the consumption rate of sodium thiosulfate increases significantly in the lower pH range. This is mainly because the stabilizing function of organic ammonium salts is not fully utilized under near-neutral to weakly alkaline conditions, and their shielding protection of thiosulfate is weakened, leading to an accelerated rate of oxidative decomposition. When the pH value is too high, the consumption rate of sodium thiosulfate is inhibited, but the leaching rate of gold begins to decrease significantly. The core mechanism is that excessive alkalinity will rapidly promote the conversion of iron ions in the solution into ferric hydroxide precipitate. This newly formed solid will physically cover or coat the surface of gold particles, severely hindering the dissolution reaction kinetics of gold. At this time, the low consumption of sodium thiosulfate actually reflects its underutilization due to the blockage of the reaction interface, rather than a simple improvement in its own stability.

[0048] Examples 16-17 Examples 16-17 provide a heap leaching process for processing low-grade gold ore. Compared with Example 1, the only difference is that the injection flow rate and the number of days of circulating leaching are different in step S3. The rest are roughly the same as Example 1, and will not be described again here.

[0049] Table 7 Test Results of Examples 16-17 As shown in Table 7, within a wide range of operating parameters, by adjusting the injection flow rate and the corresponding leaching time, this reagent system can still maintain stable and efficient leaching performance, demonstrating its operational flexibility and process robustness in actual heap leaching applications.

[0050] Example 18 This embodiment provides a method for preparing an organic ammonium salt stabilizer, the structural formula of which is: Specifically, it includes the following steps: S1. Using methyl 5-hydroxymethyl-2-furanoate (HMFC methyl ester) and 2-bromoethyl ethyl ether as starting materials, under nitrogen protection, 0.10 mol of HMFC methyl ester and 0.22 mol of anhydrous potassium carbonate were suspended in 150 mL of anhydrous N,N-dimethylformamide (DMF). While stirring at room temperature, 0.13 mol of 2-bromoethyl ethyl ether was slowly added dropwise. After the addition was complete, the reaction mixture was heated to 80 °C and stirred at this temperature for 14 hours. The reaction was then analyzed by thin-layer chromatography (TLC, developing solvent: petroleum ether / ethyl acetate = ... 3 / 1 (UV or phosphomolybdic acid color development) to monitor the disappearance of the starting material spot; after the reaction is complete, cool the mixture to room temperature, pour it into 300 mL of ice water, extract it three times with 200 mL of ethyl acetate, combine the organic phases, wash them three times with 100 mL of saturated brine to completely remove DMF, dry them with anhydrous sodium sulfate, filter them, concentrate them under reduced pressure to remove the solvent, and obtain a crude oily product. Purify it by silica gel column chromatography (elution gradient: from petroleum ether / ethyl acetate = 10 / 1 to 4 / 1) to obtain a colorless oily product methyl 5-[(2-ethoxyethoxy)methyl]-2-furanoate; S2. Dissolve 0.09 mol of the ether ester obtained in step S1 in a mixed solvent of 100 mL methanol and 20 mL deionized water. Under ice-water bath cooling and stirring, add 0.225 mol of lithium hydroxide monohydrate in portions. After the addition is complete, remove the ice bath, allow the reaction mixture to naturally warm to room temperature and continue stirring for 5 hours. Monitor the disappearance of the ester spot by TLC (evolving solvent: dichloromethane / methanol = 10 / 1). After the reaction is complete, remove most of the methanol by rotary evaporation under reduced pressure. Cool the remaining aqueous solution in an ice-water bath and slowly adjust the pH to 2-3 with dilute hydrochloric acid (1 M) under vigorous stirring. At this point, a solid or oily substance precipitates out. Extract three times with 150 mL ethyl acetate, combine the organic phases, wash with 80 mL saturated brine, dry with anhydrous sodium sulfate, filter and concentrate under reduced pressure to obtain a viscous oily substance 5-[(2-ethoxyethoxy)methyl]-2-furanic acid (intermediate A). S3. Under nitrogen protection, ice-water bath cooling, and light protection, 0.08 mol of intermediate A and 0.096 mol of N-hydroxysuccinimide were dissolved in 150 mL of anhydrous dichloromethane (DCM). The temperature was maintained at 0-5 °C. 0.096 mol of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) was added in portions. After the addition was complete, the ice bath was removed, and the reaction was stirred and activated at room temperature for 2 hours to obtain an activated N-succinimide ester solution for later use. In another dry reaction flask, 0.084 mol of N-tert-butoxycarbonyl-4-amino-2-oxobutyric acid and 0.20 mol of triethylamine were dissolved in 100 mL of anhydrous DCM and cooled in an ice bath. The previously prepared activated ester solution was slowly added dropwise to this amino acid solution through a constant pressure dropping funnel, controlling the dropping rate to maintain the internal temperature below 10 °C. After the addition was complete, the ice bath was removed, and the reaction was stirred overnight at room temperature. After the reaction was completed, the reaction solution was washed once each with 5% citric acid aqueous solution, saturated sodium bicarbonate solution, and saturated brine. The organic phase was dried with anhydrous sodium sulfate, filtered, concentrated, and the crude product was purified by silica gel column chromatography (eluent: dichloromethane / methanol = 30 / 1 to 15 / 1) to obtain the Boc protected product. The Boc protected product was dissolved in 80 mL of dichloromethane and cooled in an ice bath. Then, 20 mL of trifluoroacetic acid (TFA) was slowly added. The ice bath was removed, and the mixture was stirred at room temperature for 3 hours. The disappearance of the starting material spot was monitored by TLC. After the reaction was complete, most of the solvent and excess TFA were removed by concentration under reduced pressure to obtain a viscous oil. This oil was dissolved in 20 mL of methanol and slowly added dropwise to 300 mL of anhydrous diethyl ether with stirring, which precipitated a solid. The solid was collected by filtration, washed with diethyl ether, and dried under vacuum to obtain the trifluoroacetate salt of intermediate B. This salt was dissolved in methanol and passed through a basic ion exchange resin (AOH). - A short column of type ( ) was eluted with methanol, the eluent was collected and concentrated to obtain free amine intermediate B in an oily form; S4. Dissolve 0.06 mol of free amine intermediate B in a mixed solvent of 60 mL isopropanol and 20 mL deionized water, keeping the solution clear; dissolve 0.063 mol of sodium thiosulfate pentahydrate in 40 mL of hot water, and slowly add the sodium thiosulfate aqueous solution to the amine's alcohol aqueous solution under stirring in a water bath at 50-60 °C; after the addition is complete, the solution gradually becomes turbid; remove the water bath, allow the reaction mixture to cool slowly to room temperature naturally, and continue stirring at room temperature for 1 hour to promote complete crystallization; then place the reaction flask in an ice-water bath to cool for 1-2 hours, filter the precipitated solid through a Buchner funnel, wash the filter cake 2-3 times with a small amount of pre-cooled isopropanol / water (1:1, v / v) mixed solvent, and finally wash with a small amount of cold diethyl ether to promote drying; place the obtained white solid in a vacuum drying oven and dry overnight at 30-35 °C to obtain a white target amine salt crystal product, and confirm the structure of the product by ¹H NMR spectroscopy, such as... Figure 2As shown, in the ¹H NMR spectrum of the target compound (deuterated reagent: D₂O), the singlets at chemical shifts δ 7.8 and δ 7.4 ppm are attributed to two aromatic protons in different chemical environments on the furan ring; the doublet at δ 3.8 ppm corresponds to the methylene proton (-O-CO-CH₂-) attached to the carbonyl group, and its splitting originates from coupling with the proton on the adjacent chiral carbon; the singlet at δ 3.6 ppm is attributed to the methylene proton directly attached to the furan ring (furan-CH₂-O-); the doublet in the range of δ 3.4-3.2 ppm, with one high and one low peak, is attributed to the two methylene groups in the ethoxy chain (CH₂ in -O-CH₂-CH₂-O- and CH₂ in -O-CH₂-CH₂), respectively. Due to their similar diastereospatial environments and similar coupling constants, the signals overlap and exhibit a characteristic doublet pattern; δ 2.6 and δ 2.4 The double peaks at ppm correspond to two diastereomeric methylene protons (-CH2-N) adjacent to the chiral center. + The singlet at δ 1.8 ppm may be a signal of trace impurities in the sample; the multiplets in the δ 0.8-1.1 ppm range are attributed to the ethoxy-terminated methyl proton (-CH2-CH3). Due to the use of D2O as a solvent, the active ammonium protons (-N) on the amine salt cation... + H3 undergoes rapid exchange with deuterium, so its signal was not observed in the spectrum.

[0051] 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 gold immersion reagent system, characterized in that, It includes a gold leaching agent, a catalytic leaching agent, and a stabilizer; the gold leaching agent is glycine; the catalytic leaching agent is anhydrous sodium thiosulfate; and the stabilizer is an organic ammonium salt with the following molecular structure: 。 2. The gold immersion reagent system according to claim 1, characterized in that, In the gold leaching agent system, the mass concentration of the gold leaching agent is 25~50 g / L; the mass concentration of the catalytic leaching agent is 47.5~95 g / L; and the mass concentration of the stabilizer is 1~2 g / L.

3. A heap leaching process for processing low-grade gold ore, characterized in that, Extracting gold from low-grade gold ore using the gold leaching reagent system according to any one of claims 1-2, comprising the following steps: S1. The gold-bearing mineral material is crushed to obtain a crushed sample, and the crushed sample is added to a heap leaching column to obtain heap leaching material; S2. Mix the gold leaching agent, catalytic leaching agent and stabilizer evenly, and adjust the pH value to 8.5~9.5 to obtain the gold leaching agent system; S3. The gold leaching agent system is added from the top of the heap leaching column, and the heap leaching ore is circulated and washed to obtain gold-bearing precious solution and leaching ore tailings; S4. The gold content in the leaching mineral tailings is determined by fire assay, and the leaching rate is calculated.

4. The heap leaching process for treating low-grade gold ore according to claim 3, characterized in that, In step S1, the ore with a particle size ≤10cm accounts for 70-75% of the total mass of the crushed sample.

5. The heap leaching process for treating low-grade gold ore according to claim 3, characterized in that, In step S3, the intensity of the cyclic rinsing is 7~13 L / m. 2 ·h.

6. The heap leaching process for treating low-grade gold ore according to claim 5, characterized in that, The cyclic rinsing time is 42 to 75 days.

7. The heap leaching process for treating low-grade gold ore according to claim 3, characterized in that, The gold-bearing mineral material includes one or more of the following: oxidized heap leaching residue, low-grade roasted sand, and low-grade gold ore.

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