Arsenic Removal Gold Leaching Reagent System and Method for Treating Low-Grade Gold Ores Rich in Arsenopyrite

Abstract

This application provides a gold leaching reagent system for removing arsenic and a method for treating low-grade gold ore rich in arsenopyrite, belonging to the field of hydrometallurgical technology. The invention uses ozone, glycine, cyanoacetylurea, and 98% pure biotite as the gold leaching reagent system. Through the synergistic effect of a series of reagents, arsenic is safely introduced into the slag phase, ensuring that the solution system contains only gold. This gold leaching process is simple and easy to operate. Compared with the traditional cyanidation method, this novel reagent system can effectively inhibit the harmful reactions of arsenopyrite, selectively leach arsenic and gold in stages, and maximize the deharmonization of arsenic by introducing an arsenic removal process. Simultaneously, it ensures the singular presence of gold in the liquid phase, facilitating subsequent gold recovery. This overcomes the challenge of utilizing high-toxicity arsenopyrite and low-gold resources, meeting the strategic needs of sustainable development. This application provides a solution for treating high-arsenic, low-grade gold ore through "cyanide slow release-electrochemical catalysis-stage gold extraction".

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, specifically to a gold leaching reagent system for removing arsenic and a method for treating low-grade gold ore rich in arsenopyrite. Background Technology

[0002] Globally, easily exploitable high-grade gold resources are dwindling, leading to a persistently tight gold supply. Against this backdrop, resources abundant in arsenopyrite (arsenic pyrite), previously considered "untapped" or "useless" due to their low grade and processing difficulties, have regained strategic significance due to their enormous potential gold reserves. These resources typically contain a high proportion of arsenopyrite (FeAsS), with gold occurring in fine grains or inclusions. Unlocking their economic value is crucial for alleviating the gold supply-demand imbalance.

[0003] For the aforementioned low-grade gold resources rich in arsenopyrite, the mainstream cyanidation leaching process exhibits significant inadequacy and high risk. On the one hand, arsenopyrite is chemically reactive in alkaline cyanidation systems, consuming large amounts of cyanide and dissolved oxygen, significantly reducing the effective concentration of leaching reagents, severely interfering with and inhibiting the efficient dissolution of the target gold, resulting in low gold recovery rates, prolonged leaching cycles, and dramatically increased production costs. On the other hand, and more seriously, the arsenic in arsenopyrite readily dissolves and is released during cyanidation, generating highly toxic soluble arsenic compounds (such as arsenites and arsenates). This not only significantly increases the difficulty and cost of subsequent wastewater and waste residue treatment but also poses a major threat to the ecological environment and human health, making the traditional cyanidation method face insurmountable technical and environmental barriers when processing such resources. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides a gold leaching agent system for removing arsenic and a method for treating low-grade gold ore rich in arsenopyrite, aiming to solve the problems of low leaching efficiency, high cost and serious pollution of existing gold leaching agent systems for low-grade gold ore rich in arsenopyrite.

[0005] In a first aspect, this application provides a gold leaching agent system for removing arsenic, the gold leaching agent system comprising ozone, glycine, cyanoacetylurea and biotite with a purity of 98%.

[0006] In the technical solution of this application embodiment, by designing a gold leaching agent system for removing arsenic, the arsenic lattice is destroyed and the encapsulated gold is released under the oxidation of ozone. At the same time, ozone oxidizes part of the gold into active Au. + Under the condition of introducing glycine, Fe is continuously dissolved from biotite in the mineral. 2+ / Fe 3+ It forms a bifunctional stable complex with glycine: on the one hand, glycine binds Fe through carboxyl-amino bidentate coordination.3+ Generate water-soluble Fe 3+ / Fe 2+ The redox potential of the system is precisely controlled by an electrochemical cyclic catalysis method to catalyze the alkaline hydrolysis of cyanoacetamide, thereby driving the slow release efficiency of cyanide ions. Fe 3+ The electron is extracted from the methylene group of cyanoacetylurea, triggering the breaking of the C≡N bond and generating a free cyanide ion (CN). - Under the influence of excess ozone, Fe 2+ Re-oxidized to Fe 3+ To achieve electrochemical equilibrium in the system, cyanide ions are released gradually (concentration stabilized at 5-10 ppm), and dissolved gold ions form [Au(CN)2]. - Complex. Simultaneously, glycine dissolves the As released from the dissolution of arsenopyrite. 3+ Arsenic reacts with free glycine anions to form a soluble chelate, which enters the liquid phase. This not only eliminates the poisoning effect of arsenic on the ferroelectric pair but also promotes the continuous disintegration of the arsenopyrite lattice through chemical dissociation (dissolution), exposing the gold inclusions and promoting the deep decomposition of arsenopyrite. Ultimately, the toxic element arsenic is directionally enriched in the liquid phase. After gold dissolution is complete, dilute hydrochloric acid is added to the system to adjust the pH to acidic, allowing the dissolved pentavalent arsenic (As...) to... 5+ The gold complex combines with the iron ions continuously released from biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent arsenic fixation (fixation rate > 99.5%). Meanwhile, the gold complex transforms into a water-soluble cationic species ([Au(Cl)4)) under acidic conditions. - Arsenic exists stably in the liquid phase. Through solid-liquid separation, arsenic enters the slag phase as a safe mineral phase, ensuring that the solution system contains only gold, thus laying the foundation for efficient gold recovery in the future.

[0007] Secondly, this application provides a method for treating low-grade gold ore rich in arsenopyrite using an arsenic removal gold leaching reagent system, comprising the following steps:

[0008] S1. The low-grade gold ore rich in arsenopyrite is crushed to obtain the crushed sample;

[0009] S2. Add biotite with a purity of 98% to the crushed sample, stir evenly, and then add it to the heap leaching column to obtain heap leaching ore;

[0010] S3. A mixed solution of glycine and cyanoacetamide is added from the top of the heap leaching column to leach the heap leaching material from top to bottom. The outflowing leachate is collected and pumped back to the top of the heap leaching column for circulating leaching. After the circulating leaching is completed, a gold- and arsenic-containing precious solution and leaching tailings are obtained. During the leaching, ozone is introduced into the leachate through an aeration device.

[0011] S4. Adjust the pH of the gold- and arsenic-containing precious solution to obtain ferric arsenate precipitate, and then separate the solid and liquid to obtain a gold immersion solution.

[0012] In the technical solution of this application embodiment, a method for treating low-grade gold ore rich in arsenopyrite is designed by using an arsenic removal gold leaching agent system. The above-mentioned arsenic removal gold leaching agent system is used to treat low-grade gold ore rich in arsenopyrite. The gold leaching process is simple and easy to operate. Compared with the traditional cyanidation method, this new agent system can effectively inhibit the harmful reaction of arsenopyrite, selectively leach arsenic and gold in stages, and maximize the harmlessness of arsenic by introducing an arsenic removal process. At the same time, it ensures that gold exists in the liquid phase system, which is convenient for subsequent gold recovery. This method overcomes the problem of high-toxicity arsenopyrite and low gold resource utilization and meets the strategic needs of sustainable development.

[0013] In some embodiments, in step S2, the biotite with a purity of 98% accounts for 5-10% of the mass of the crushed sample, and the biotite with a purity of 98% has a particle size of -0.074 mm and a content of 75-85%.

[0014] In this embodiment, Fe can be continuously dissolved from biotite. 2+ / Fe 3+ This provides a continuous supply of the ions required for the reaction in the gold immersion system.

[0015] In some embodiments, in step S3, the mass concentration of glycine in the mixed solution is 10~50 g / L, and the mass concentration of cyanoacetamide in the mixed solution is 1~10 g / L.

[0016] In this embodiment, glycine binds to Fe via carboxyl-amino bidentate coordination. 3+ Generate water-soluble Simultaneously, glycine dissolves the As released from the dissolved arsenopyrite. 3+ It forms a soluble chelate with free glycine anions, enters the liquid phase, and not only eliminates the poisoning effect of arsenic on the ferroelectric pair, but also promotes the continuous disintegration of the arsenopyrite lattice through chemical dissociation (dissolution) effect, exposing the gold coating and promoting the deep decomposition of arsenopyrite. Ultimately, the toxic element arsenic is directionally enriched in the liquid phase. 3+ / Fe 2+ The redox potential of the system is precisely controlled by an electrochemical cyclic catalysis method to catalyze the alkaline hydrolysis of cyanoacetamide, thereby driving the slow release efficiency of cyanide ions. Fe 3+ The electron is extracted from the methylene group of cyanoacetylurea, triggering the breaking of the C≡N bond and generating a free cyanide ion (CN). - Under the influence of excess ozone, Fe 2+ Re-oxidized to Fe 3+ Achieve electrochemical equilibrium in the system to achieve sustained cyanide release (concentration stabilized at 5-10 ppm).

[0017] In some embodiments, in step S3, the pH value of the mixed solution is ≥10.

[0018] In this embodiment, the gold leaching system is carried out in a strongly alkaline environment to ensure that glycine exists in the form of glycine anions and that the cyanide ions released by the slow-release cyanoacetamide remain stably present in the solution system, preventing the generation of cyanide gas. In some embodiments, in step S3, the ozone aeration flow rate is 0.05~0.1m³. 3 / h·L.

[0019] In this embodiment, under the oxidizing effect of ozone, the lattice of the arsenopyrite crystal is destroyed, releasing the encapsulated gold. At the same time, ozone oxidizes some of the gold into active Au. + .

[0020] In some embodiments, in step S3, the intensity of the cyclic rinsing is 10 L / m. 2 The rinsing time is 720 h, and the total volume of the mixed solution in the rinsing is 10 L.

[0021] In this embodiment, the leaching reaction is fully carried out through cyclic rinsing.

[0022] In some embodiments, in step S1, the ore particle size of the crushed sample is -0.074 mm and the content is 75~85%.

[0023] In this embodiment, the sample is crushed to facilitate the subsequent leaching reaction.

[0024] In some embodiments, in step S3, the outlet of the aeration device is buried at the bottom of the heap leaching material.

[0025] In this embodiment, the aeration device is buried at the bottom, and ozone is injected directly from the bottom. The bubbles move upward naturally under the influence of buoyancy. This creates a forced convection path across the entire height of the ore pile, allowing the bubbles to penetrate the pore network of the ore pile and deliver ozone more evenly to all levels of the pile, especially the upper and middle areas. This is much more efficient than relying solely on top aeration or natural diffusion.

[0026] In some embodiments, in step S4, the pH-adjusting agent is dilute hydrochloric acid with a concentration of 0.1~1 mol / L, and the pH value is adjusted to 2~3.

[0027] In this embodiment, the immersion solution is adjusted to be acidic, and the dissolved pentavalent arsenic (As) 5+ The gold complex combines with the iron ions continuously released from biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent arsenic fixation (fixation rate > 99.5%). Meanwhile, the gold complex transforms into a water-soluble cationic species ([Au(Cl)4)) under acidic conditions. - It exists stably in the liquid phase.

[0028] 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

[0029] 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.

[0030] Figure 1 The images shown are SEM images of biotite before and after leaching, and energy dispersive spectroscopy (EDS) images of various elements in biotite, as presented in the embodiments of this application.

[0031] Figure 2 The following are electron microscopy-energy dispersive spectroscopy (EDS) analysis diagrams in the embodiments of this application: (a) is a morphology diagram of arsenopyrite before leaching, (b) is a morphology diagram of arsenopyrite after leaching for 24 hours, (c) is a morphology diagram of arsenopyrite after leaching for 48 hours, and (d) is an EDS analysis diagram of arsenopyrite after leaching for 48 hours.

[0032] Figure 3 This is a flowchart illustrating the process of using an arsenic removal leaching agent system to treat low-grade gold ore rich in arsenopyrite, as described in this application. Detailed Implementation

[0033] The embodiments of the technical solution of this application are described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.

[0034] 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.

[0035] To address the problems of low leaching efficiency, high cost, and severe pollution associated with existing gold leaching systems for low-grade gold ores rich in arsenopyrite, this application provides an arsenic removal gold leaching system and a method for treating such ores. By designing an arsenic removal gold leaching system, under the oxidation of ozone, the arsenopyrite crystal lattice is destroyed, releasing the encapsulated gold. Simultaneously, ozone oxidizes some of the gold into active Au. +Under the condition of introducing glycine, Fe is continuously dissolved from biotite in the mineral. 2+ / Fe 3+ It forms a bifunctional stable complex with glycine: on the one hand, glycine binds Fe through carboxyl-amino bidentate coordination. 3+ Generate water-soluble Fe 3+ / Fe 2+ The redox potential of the system is precisely controlled by an electrochemical cyclic catalysis method to catalyze the alkaline hydrolysis of cyanoacetamide, thereby driving the slow release efficiency of cyanide ions. Fe 3+ The electron is extracted from the methylene group of cyanoacetylurea, triggering the breaking of the C≡N bond and generating a free cyanide ion (CN). - Under the influence of excess ozone, Fe 2+ Re-oxidized to Fe 3+ To achieve electrochemical equilibrium in the system, cyanide ions are released gradually (concentration stabilized at 5-10 ppm), and dissolved gold ions form [Au(CN)2]. - Complex. Simultaneously, glycine dissolves the As released from the dissolution of arsenopyrite. 3+ Arsenic reacts with free glycine anions to form a soluble chelate, which enters the liquid phase. This not only eliminates the poisoning effect of arsenic on the ferroelectric pair but also promotes the continuous disintegration of the arsenopyrite lattice through chemical dissociation (dissolution), exposing the gold inclusions and promoting the deep decomposition of arsenopyrite. Ultimately, the toxic element arsenic is directionally enriched in the liquid phase. After gold dissolution is complete, dilute hydrochloric acid is added to the system to adjust the pH to acidic, allowing the dissolved pentavalent arsenic (As...) to... 5+ The gold complex combines with the iron ions continuously released from biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent arsenic fixation (fixation rate > 99.5%). Meanwhile, the gold complex transforms into a water-soluble cationic species ([Au(Cl)4)) under acidic conditions. - Arsenic exists stably in the liquid phase. Through solid-liquid separation, arsenic enters the slag phase as a safe mineral phase, ensuring that the solution system contains only gold, laying the foundation for efficient gold recovery. This gold leaching process is simple and easy to operate. Compared with the traditional cyanidation method, this novel reagent system can effectively inhibit the harmful reactions of arsenopyrite, selectively leach arsenic and gold in stages, and maximize the harmlessness of arsenic by introducing an arsenic removal process, while ensuring the single existence of gold in the liquid phase system, facilitating subsequent gold recovery. This overcomes the problem of utilizing high-arsenic and low-gold resources, meets the strategic needs of sustainable development, and provides a solution for the treatment of high-arsenic and low-grade gold ores through "cyanide slow release-electrochemical catalysis-stage gold extraction".

[0036] In a first aspect, this application provides a gold leaching agent system for removing arsenic, the gold leaching agent system comprising ozone, glycine, cyanoacetylurea and biotite with a purity of 98%.

[0037] In the technical solution of this application embodiment, by removing the arsenic leaching agent system, the arsenopyrite lattice is destroyed and the encapsulated gold is released under the oxidation of ozone. At the same time, ozone oxidizes some of the gold into active Au. + Under the condition of introducing glycine, Fe is continuously dissolved from biotite in the mineral. 2+ / Fe 3+ It forms a bifunctional stable complex with glycine: on the one hand, glycine binds Fe through carboxyl-amino bidentate coordination. 3+ Generate water-soluble Fe 3+ / Fe 2+ The redox potential of the system is precisely controlled by an electrochemical cyclic catalysis method to catalyze the alkaline hydrolysis of cyanoacetamide, thereby driving the slow release efficiency of cyanide ions. Fe 3+ The electron is extracted from the methylene group of cyanoacetylurea, triggering the breaking of the C≡N bond and generating a free cyanide ion (CN). - Under the influence of excess ozone, Fe 2+ Re-oxidized to Fe 3+ To achieve electrochemical equilibrium in the system, cyanide ions are released gradually (concentration stabilized at 5-10 ppm), and dissolved gold ions form [Au(CN)2]. - Complex. Simultaneously, glycine dissolves the As released from the dissolution of arsenopyrite. 3+ Arsenic reacts with free glycine anions to form a soluble chelate, which enters the liquid phase. This not only eliminates the poisoning effect of arsenic on the ferroelectric pair but also promotes the continuous disintegration of the arsenopyrite lattice through chemical dissociation (dissolution), exposing the gold inclusions and promoting the deep decomposition of arsenopyrite. Ultimately, the toxic element arsenic is directionally enriched in the liquid phase. After gold dissolution is complete, dilute hydrochloric acid is added to the system to adjust the pH to acidic, allowing the dissolved pentavalent arsenic (As...) to... 5+ The gold complex combines with the iron ions continuously released from biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent arsenic fixation (fixation rate > 99.5%). Meanwhile, the gold complex transforms into a water-soluble cationic species ([Au(Cl)4)) under acidic conditions. - Arsenic exists stably in the liquid phase. Through solid-liquid separation, arsenic enters the slag phase as a safe mineral phase, ensuring that the solution system contains only gold, thus laying the foundation for efficient gold recovery in the future.

[0038] Secondly, this application provides a method for treating low-grade gold ore rich in arsenopyrite using an arsenic removal gold leaching reagent system, comprising the following steps:

[0039] S1. The low-grade gold ore rich in arsenopyrite is crushed to obtain the crushed sample;

[0040] S2. Add biotite with a purity of 98% to the crushed sample, stir evenly, and then add it to the heap leaching column to obtain heap leaching ore;

[0041] S3. A mixed solution of glycine and cyanoacetamide is added from the top of the heap leaching column to leach the heap leaching material from top to bottom. The outflowing leachate is collected and pumped back to the top of the heap leaching column for circulating leaching. After the circulating leaching is completed, a gold- and arsenic-containing precious solution and leaching tailings are obtained. During the leaching, ozone is introduced into the leachate through an aeration device.

[0042] S4. Adjust the pH of the gold- and arsenic-containing precious solution to obtain ferric arsenate precipitate, and then separate the solid and liquid to obtain a gold immersion solution.

[0043] In the technical solution of this application embodiment, a method for treating low-grade gold ore rich in arsenopyrite is designed by using an arsenic removal gold leaching agent system. The above-mentioned arsenic removal gold leaching agent system is used to treat low-grade gold ore rich in arsenopyrite. The gold leaching process is simple and easy to operate. Compared with the traditional cyanidation method, this new agent system can effectively inhibit the harmful reaction of arsenopyrite, selectively leach arsenic and gold in stages, and maximize the harmlessness of arsenic by introducing an arsenic removal process. At the same time, it ensures that gold exists in the liquid phase system, which is convenient for subsequent gold recovery. This method overcomes the problem of high-toxicity arsenopyrite and low gold resource utilization and meets the strategic needs of sustainable development.

[0044] Furthermore, in some embodiments, in step S2, the biotite with a purity of 98% accounts for 5-10% of the mass of the crushed sample, and the biotite with a purity of 98% has a particle size of -0.074mm and a content of 75-85%.

[0045] In the technical solution of this application embodiment, Fe is continuously dissolved from biotite. 2+ / Fe 3+ This provides a continuous supply of the ions required for the reaction in the gold immersion system.

[0046] Furthermore, in some embodiments, in step S3, the mass concentration of glycine in the mixed solution is 10~50 g / L, and the mass concentration of cyanoacetamide in the mixed solution is 1~10 g / L.

[0047] In the technical solution of this application embodiment, glycine binds to Fe through carboxyl-amino bidentate coordination. 3+ Generate water-soluble Simultaneously, glycine dissolves the As released from the dissolved arsenopyrite. 3+ It forms a soluble chelate with free glycine anions, enters the liquid phase, and not only eliminates the poisoning effect of arsenic on the ferroelectric pair, but also promotes the continuous disintegration of the arsenopyrite lattice through chemical dissociation (dissolution) effect, exposing the gold coating and promoting the deep decomposition of arsenopyrite. Ultimately, the toxic element arsenic is directionally enriched in the liquid phase. 3+ / Fe 2+The redox potential of the system is precisely controlled by an electrochemical cyclic catalysis method to catalyze the alkaline hydrolysis of cyanoacetamide, thereby driving the slow release efficiency of cyanide ions. Fe 3+ The electron is extracted from the methylene group of cyanoacetylurea, triggering the breaking of the C≡N bond and generating a free cyanide ion (CN). - Under the influence of excess ozone, Fe 2+ Re-oxidized to Fe 3+ Achieve electrochemical equilibrium in the system to achieve sustained cyanide release (concentration stabilized at 5-10 ppm).

[0048] Furthermore, in some embodiments, in step S3, the pH value of the mixed solution is ≥10.

[0049] In the technical solution of this application embodiment, the immersion gold system is carried out in a strongly alkaline environment to ensure that glycine exists in the form of glycine anions and that the cyanide ions released by the slow release of cyanoacetylurea are stably present in the solution system, thus preventing the generation of cyanide gas.

[0050] Furthermore, in some embodiments, in step S3, the ozone aeration flow rate is 0.05~0.1m³. 3 / h·L.

[0051] In the technical solution of this application embodiment, under the oxidation of ozone, the lattice of arsenopyrite is destroyed, releasing the encapsulated gold. At the same time, ozone oxidizes some of the gold into active Au. + .

[0052] Furthermore, in some embodiments, in step S3, the intensity of the cyclic rinsing is 10 L / m. 2 The rinsing time is 720 h, and the total volume of the mixed solution in the rinsing is 10 L.

[0053] In the technical solution of this application embodiment, the leaching reaction is fully carried out through cyclic rinsing.

[0054] Furthermore, in some embodiments, in step S1, the ore particle size of the crushed sample is -0.074 mm and the content is 75~85%.

[0055] In the technical solution of this application embodiment, the sample is crushed to facilitate the subsequent leaching reaction.

[0056] Furthermore, in some embodiments, in step S3, the outlet of the aeration device is buried at the bottom of the heap leaching material.

[0057] In the technical solution of this application embodiment, the aeration device is buried at the bottom, and ozone is injected directly from the bottom. The bubbles move upward naturally under the action of buoyancy. This forms a forced convection path throughout the entire height of the ore pile, allowing the bubbles to penetrate the pore network of the ore pile and deliver ozone more evenly to all levels of the ore pile, especially the middle and upper regions. This is much more efficient than relying solely on top aeration or natural diffusion.

[0058] Furthermore, in some embodiments, in step S4, the pH-adjusting agent is dilute hydrochloric acid with a concentration of 0.1~1 mol / L, and the pH value is adjusted to 2~3.

[0059] In the technical solution of this application embodiment, the immersion solution is adjusted to be acidic, and the dissolved pentavalent arsenic (As) 5+ The gold complex combines with the iron ions continuously released from biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent arsenic fixation (fixation rate > 99.5%). Meanwhile, the gold complex transforms into a water-soluble cationic species ([Au(Cl)4)) under acidic conditions. - It exists stably in the liquid phase.

[0060] 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.

[0061] Example 1

[0062] Example 1 provides a gold leaching agent system for removing arsenic, the gold leaching agent system comprising ozone, glycine, cyanoacetylurea and biotite with a purity of 98%.

[0063] The treatment of low-grade gold ore rich in arsenopyrite using the above-mentioned gold leaching reagent system specifically includes the following steps:

[0064] (1) The low-grade gold ore rich in arsenopyrite was crushed to a particle size of -0.074 mm, with the mineral powder accounting for 80% of the total mass of the material, and the crushed sample was obtained.

[0065] (2) Mix the crushed sample with biotite of the same particle size and purity of 98% evenly, and add it into a heap leaching column with a height of 1.2m and an inner diameter of 10cm. The heap leaching material is piled up to a height of 1m. Biotite accounts for 7% of the mass of the crushed sample in the heap leaching material.

[0066] (3) Adjust the pH of the mixed solution of glycine (30 g / L) and cyanoacetamide (5 g / L) to 10, and then add it from the top of the heap leaching column. Leach the ore through the heap leaching column, collect the outflowing leachate, and pump it back to the top of the heap leaching column for circulation leaching. The total volume of the mixed solution in the circulation process is 10 L, and the leaching intensity is 10 L / m. 2 The leaching process involves circulating ozone for 720 hours. During this process, ozone is introduced into the leachate via an aeration device. The outlet of the aeration device is buried at the bottom of the heap leaching material, and the ozone aeration velocity is 0.05 m / s². 3 / h·L. At the end of the cycle, a gold- and arsenic-containing precious solution and mineral leaching tailings are obtained;

[0067] (4) Add 1 mol / L of dilute hydrochloric acid to the gold and arsenic-containing solution to adjust the pH value to 2, and ferric arsenate precipitate is obtained. Then, solid-liquid separation is performed to obtain the gold immersion solution.

[0068] The source and performance parameters of the raw materials are as follows:

[0069] The low-grade gold ore rich in arsenopyrite comes from a gold mine in Kyrgyzstan. The gold grade is 0.73 g / t, and the arsenic content is 7-14% of the total ore mass.

[0070] The gold content in the leaching tailings of each embodiment and comparative example was determined using the fire assay method, and the testing and analysis methods were in accordance with GB / T 7739 "Chemical Analysis Methods for Gold Concentrates". Therefore, the gold leaching rate η was...

[0071]

[0072] Where η represents the gold leaching rate, in %; m1 represents the mass of the original arsenopyrite-rich low-grade gold ore, in g; β1 represents the grade of the original arsenopyrite-rich low-grade gold ore, in g / t; m2 represents the mass of the residue after leaching the arsenopyrite-rich low-grade gold ore, in g; and β2 represents the grade of the residue after leaching the arsenopyrite-rich low-grade gold ore, in g / t.

[0073] The concentrations of gold and arsenic in the gold- and arsenic-containing solutions of each embodiment and comparative example were then detected by ICP-OES. The gold leaching rate test results of the two methods were compared, and data with a deviation of less than 1% between the test results of the two methods were considered valid. Finally, the gold leaching rate in each embodiment and comparative example was determined.

[0074] The concentration of arsenic in gold-containing and arsenic-containing precious solutions and the concentration of arsenic in gold immersion solutions were measured by ICP-OES, and the arsenic removal rate and curing rate were calculated respectively.

[0075] In Example 1, the curing rate of arsenic was 99.5%, while the gold complex was converted into a water-soluble cationic species ([Au(Cl)4)) under acidic conditions.- Arsenic exists stably in the liquid phase. Through solid-liquid separation, arsenic enters the slag phase as a safe mineral phase, ensuring that the solution system contains only gold, thus laying the foundation for efficient gold recovery in the future.

[0076] During the leaching process in Example 1, 50 mL of gold and arsenic-containing precious solutions were collected at different time points, and the concentrations of cyanide and iron were detected by ICP-OES. The results are shown in Table 1.

[0077] Table 1. Concentrations of free cyanide and iron in gold- and arsenic-containing precious solutions.

[0078]

[0079] As shown in Table 1, although no cyanide was added to the system, free cyanide was detected, proving that cyanoaceture continuously hydrolyzes in alkaline slurry to generate free cyanide ions, and the concentration of cyanide ions changes dynamically: In the early stage (36~144h): the cyanide concentration increased from 8.2 mg / L to 16.3 mg / L (peak), reflecting the gradual decomposition of cyanoaceture to release active cyano groups, providing a stable coordination source for gold dissolution; in the middle stage (216~432h): the concentration remained at 10.5~14.2 mg / L, confirming the slow-release effect to ensure the continuous progress of the gold leaching reaction; in the late stage (576~748h): the concentration dropped sharply from 10.3 mg / L to 5.42 mg / L, because the cyanide ions were consumed by other dissolved metal ions and the decomposition of cyanoaceture was close to complete.

[0080] After leaching, the residual solids were collected, and the state and iron content distribution of the biotite before and after leaching were observed by SEM combined with energy dispersive spectroscopy. The results are as follows: Figure 1 As shown in Tables 2 and 3.

[0081] Table 2. Distribution of iron content in biotite before leaching.

[0082]

[0083] Table 3. Distribution of iron content in biotite after leaching.

[0084]

[0085] pass Figure 1 Tables 2 and 3 reveal the migration pattern of iron in biotite during the reaction process. The average iron content changes from high (14.98%) to low (1.52%). The low-iron-content surface layer peels off, exposing a new surface layer with a high iron content. Biotite, as the source of iron, forms Fe... 3+ / Fe 2+ The redox couple drives the positive reaction of gold and arsenic in the reagent system. Therefore, the dissolution of biotite continuously releases iron to form Fe. 3+ / Fe2+ Redox couples drive the synergistic leaching of gold and arsenic through a surface etching and stripping mechanism, ensuring the efficient leaching of the reagent system.

[0086] In this embodiment, during the leaching process, leachate and leaching tailings were collected at leaching time points of 6h, 12h, 24h, 36h, and 48h. The concentrations of arsenic and iron in the leachate were tested using an ICP-OES analyzer, as shown in Table 4. Furthermore, the changes in the occurrence speciation of arsenopyrite were observed using scanning electron microscopy combined with energy dispersive spectroscopy. Figure 2 As shown.

[0087] Table 4. Concentrations of arsenic and iron in leachate at different time points

[0088]

[0089] Deep decomposition and targeted removal of arsenopyrite: Under the synergistic effect of ozone oxidation and alkaline glycine, the arsenopyrite (FeAsS) lattice is targeted by ozone, causing the As-S bonds to break and releasing encapsulated gold and arsenic species; glycine simultaneously chelates the dissolved As. 3+ / As 5+ A water-soluble [As(Gly)3] complex is formed, achieving liquid-phase arsenic enrichment (ICP-OES detection of arsenic concentration in the precious solution >2000ppm), and significantly reducing residual arsenic in the tailings.

[0090] Morphological alteration evidence of arsenopyrite: Electron microscopy-energy dispersive spectroscopy analysis will show that the surface of arsenopyrite particles exhibits honeycomb-like corrosion (disintegration of the original dense structure), and the arsenic content in the residual arsenopyrite decreases by more than 90% compared to the initial value, confirming the selective dissolution ability of the ozone-glycine system for arsenopyrite.

[0091] Examples 2-3 and Comparative Examples 1-2

[0092] Examples 2-3 and Comparative Examples 1-2 respectively provide a method for treating low-grade gold ore rich in arsenopyrite using a gold leaching agent system for removing arsenic. The difference between Example 1 and Example 2 is that the pH value of the mixed solution in step (3) is different, as shown in Table 5. The other steps are roughly the same as in Example 1, and will not be repeated here.

[0093] Table 5 shows the pH value, gold leaching rate, and arsenic removal rate of the mixed solutions in Examples 1-3 and Comparative Examples 1-2.

[0094]

[0095] As shown in Table 5, the pH value of the mixed solution has a significant impact on the leaching rate of gold and the removal rate of arsenic. When pH ≥ 10, the system can efficiently leach gold (≥ 92%) and simultaneously remove arsenic at a deep level (≥ 95%); however, if pH ≤ 9 (Comparative Examples 1-2), the leaching rate of gold drops sharply (≤ 7%), and although the removal rate of arsenic can reach 92% at pH = 9, gold can hardly be leached at this point.

[0096] Examples 4-5 and Comparative Examples 3-4

[0097] Examples 4-5 and Comparative Examples 3-4 respectively provide a method for treating low-grade gold ore rich in arsenopyrite using a gold leaching agent system for removing arsenic. The difference from Example 1 is that the mass concentration of glycine in step (3) is different, as shown in Table 6. The other steps are roughly the same as in Example 1, and will not be repeated here.

[0098] Table 6 shows the mass concentration of glycine and the leaching rates of gold and arsenic in Examples 4-5 and Comparative Examples 3-4.

[0099]

[0100] As shown in Table 6, glycine concentration significantly regulates the leaching of arsenic and gold through a dual mechanism: when the glycine concentration is between 10 and 50 g / L, the system can simultaneously achieve efficient gold leaching (≥90%) and deep arsenic removal (≥92%); while excessive glycine, although maintaining a high arsenic removal rate, affects the gold leaching rate. This indicates that sufficient glycine can fully chelate the high-valence arsenic produced by ozone oxidation of arsenopyrite, forming a stable water-soluble complex and blocking the secondary encapsulation of gold particles by arsenic; while when the glycine content is too low, although ozone can partially oxidize arsenopyrite to release arsenic (gold leaching rate 79%), the arsenic removal rate drops sharply to 32%, proving that glycine can chelate oxidized arsenic to form a stable water-soluble complex, preventing the re-adsorption or precipitation of arsenic.

[0101] Examples 6-7 and Comparative Examples 5-6

[0102] Examples 6-7 and Comparative Examples 5-6 respectively provide a method for treating low-grade gold ore rich in arsenopyrite using a gold leaching agent system for removing arsenic. The difference from Example 1 is that the mass concentration of cyanoacetamide in step (3) is different, as shown in Table 7. The other steps are roughly the same as in Example 1 and will not be repeated here.

[0103] Table 7 shows the mass concentration of cyanoacetamide and the leaching rates of gold and arsenic in Examples 6-7 and Comparative Examples 5-6.

[0104]

[0105] As shown in Table 7, the concentration of cyanoacetamide has a significant threshold effect on the gold leaching rate, while the arsenic removal rate remains stable. As a slow-release agent for free cyanide, cyanoacetamide needs to reach a critical concentration (≥1 g / L) to efficiently dissolve gold. When the concentration of cyanoacetamide is too low, the gold leaching rate drops sharply to 41%, but it does not affect the arsenic removal rate, indicating that this component dissolves free gold through specific coordination and does not compete with arsenic for the reaction pathway.

[0106] Examples 8-9 and Comparative Examples 7-8

[0107] Examples 8-9 and Comparative Examples 7-8 respectively provide a method for treating low-grade gold ore rich in arsenic using a gold leaching agent system for removing arsenic. The difference from Example 1 is that the ozone aeration flow rate in step (3) is different, as shown in Table 8. The other steps are roughly the same as in Example 1, and will not be repeated here.

[0108] Table 8 shows the ozone aeration flow rate and the gold leaching rate and arsenic removal rate in Examples 8-9 and Comparative Examples 7-8.

[0109]

[0110] As shown in Table 8, the ozone aeration flow rate significantly affects the gold-arsenic separation efficiency by regulating the degree of mineral oxidation: when the flow rate is ≥0.05 m... 3 / h·L, gold leaching rate ≥92%, arsenic removal rate ≥95%; when the ozone aeration flow rate continues to increase, the gold leaching rate and arsenic removal rate remain basically unchanged. This is because the sufficient ozone explosive flow can completely destroy the arsenopyrite lattice, release the encapsulated fine gold particles, and at the same time fully oxidize arsenic and gold to high valence states, promote the efficient chelation and fixation of arsenic by glycine, and the slow release and decomposition of cyanoacetylurea into cyanide ions to react with gold ions. At the same time, it is beneficial to the balance of ferrous / ferric couples in biotite and the cycle of the catalytic system. When the ozone aeration flow rate is too low, the gold leaching rate is only 49% (far lower than 92% in Example 1), which confirms that ozone destroys the arsenopyrite lattice through explosive oxidation, releases the encapsulated fine gold particles, and at the same time converts gold into high valence states of ions.

[0111] Examples 10-11 and Comparative Examples 9-10

[0112] Examples 10-11 and Comparative Examples 9-10 respectively provide a method for treating low-grade gold ore rich in arsenopyrite using a gold leaching agent system for removing arsenic. The difference from Example 1 is that the mass fraction of biotite in step (3) is different, as shown in Table 9. The other steps are roughly the same as in Example 1 and will not be repeated here.

[0113] Table 9 shows the mass fraction of biotite and the leaching rates of gold and arsenic in Examples 10-11 and Comparative Examples 9-10.

[0114]

[0115] As shown in Table 9, when the mass fraction of biotite is 5-10%, its ferroelectric pairs catalyze the slow-release decomposition of cyanoacetylurea, with a gold leaching rate ≥90% and an arsenic removal rate ≥95%. When the proportion is below 5%, the redox electron density of the ferroelectric pairs is insufficient, making it difficult to regulate the redox balance through charge transfer, thus affecting the leaching of gold and the removal of arsenic. When the proportion is above 10%, it does not increase further.

[0116] In summary, this application provides a gold leaching reagent system for removing arsenic and a method for treating low-grade gold ore rich in arsenopyrite. The specific principle is as follows: Figure 3 As shown, by designing a gold leaching agent system for removing arsenic, the arsenic lattice is destroyed and gold is released under the oxidation of ozone. At the same time, ozone oxidizes some of the gold into active Au. + Under the condition of introducing glycine, Fe is continuously dissolved from biotite in the mineral. 2+ / Fe 3+ It forms a bifunctional stable complex with glycine: on the one hand, glycine binds Fe through carboxyl-amino bidentate coordination. 3+ Generate water-soluble Fe 3+ / Fe 2+ The redox potential of the system is precisely controlled by an electrochemical cyclic catalysis method to catalyze the alkaline hydrolysis of cyanoacetamide, thereby driving the slow release efficiency of cyanide ions. Fe 3+ The electron is extracted from the methylene group of cyanoacetylurea, triggering the breaking of the C≡N bond and generating a free cyanide ion (CN). - Under the influence of excess ozone, Fe 2+ Re-oxidized to Fe 3+ To achieve electrochemical equilibrium in the system, cyanide ions are released gradually (concentration stabilized at 5-10 ppm), and dissolved gold ions form [Au(CN)2]. - Complex. Simultaneously, glycine dissolves the As released from the dissolution of arsenopyrite. 3+ Arsenic reacts with free glycine anions to form a soluble chelate, which enters the liquid phase. This not only eliminates the poisoning effect of arsenic on the ferroelectric pair but also promotes the continuous disintegration of the arsenopyrite lattice through chemical dissociation (dissolution), exposing the gold inclusions and promoting the deep decomposition of arsenopyrite. Ultimately, the toxic element arsenic is directionally enriched in the liquid phase. After gold dissolution is complete, dilute hydrochloric acid is added to the system to adjust the pH to acidic, allowing the dissolved pentavalent arsenic (As...) to... 5+ The gold complex combines with the iron ions continuously released from biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent arsenic fixation (fixation rate > 99.5%). Meanwhile, the gold complex transforms into a water-soluble cationic species ([Au(Cl)4)) under acidic conditions. -Arsenic exists stably in the liquid phase. Through solid-liquid separation, arsenic enters the slag phase as a safe mineral phase, ensuring that the solution system contains only gold, laying the foundation for efficient gold recovery. This gold leaching process is simple and easy to operate. Compared with the traditional cyanidation method, this novel reagent system can effectively inhibit the harmful reactions of arsenopyrite, selectively leach arsenic and gold in stages, and maximize the harmlessness of arsenic by introducing an arsenic removal process, while ensuring the single existence of gold in the liquid phase system, facilitating subsequent gold recovery. This overcomes the problem of utilizing high-arsenic and low-gold resources, meets the strategic needs of sustainable development, and provides a solution for the treatment of high-arsenic and low-grade gold ores through "cyanide slow release-electrochemical catalysis-stage gold extraction".

[0117] 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 method for treating low-grade gold ore rich in arsenopyrite using a gold leaching reagent system for removing arsenic, characterized in that, Includes the following steps: S1. The low-grade gold ore rich in arsenopyrite is crushed to obtain the crushed sample; S2. Add biotite with a purity of 98% to the crushed sample, stir evenly, and then add it to the heap leaching column to obtain heap leaching ore; S3. A mixed solution of glycine and cyanoacetamide is added from the top of the heap leaching column to leach the heap leaching material from top to bottom. The outflowing leachate is collected and pumped back to the top of the heap leaching column for circulating leaching. After the circulating leaching is completed, a gold- and arsenic-containing precious solution and leaching tailings are obtained. During the leaching, ozone is introduced into the leachate through an aeration device. S4. The pH value of the gold- and arsenic-containing precious solution is adjusted to obtain ferric arsenate precipitate, and then solid-liquid separation is performed to obtain gold leaching solution; The biotite with a purity of 98% accounts for 5-10% of the mass of the crushed sample. The mass concentration of glycine in the mixed solution is 10~50 g / L, and the mass concentration of cyanoacetamide in the mixed solution is 1~10 g / L; The pH value of the mixed solution is ≥10; The ozone aeration flow rate is 0.05~0.1m³. 3 / h·L.

2. The method for treating low-grade gold ore rich in arsenopyrite using the gold leaching reagent system for removing arsenic according to claim 1, characterized in that, In step S2, the content of biotite with a purity of 98% and a particle size of -0.074 mm is 75-85%.

3. The method for treating low-grade gold ore rich in arsenopyrite using the gold leaching reagent system for removing arsenic according to claim 1, characterized in that, In step S3, the intensity of the cyclic rinsing is 10 L / m. 2 The rinsing time is 720 h, and the total volume of the mixed solution in the rinsing is 10 L.

4. The method for treating low-grade gold ore rich in arsenopyrite using the gold leaching reagent system for removing arsenic according to claim 1, characterized in that, In step S1, the content of ore particles with a size of -0.074 mm in the crushed sample is 75-85%.

5. The method for treating low-grade gold ore rich in arsenopyrite using the gold leaching reagent system for removing arsenic according to claim 1, characterized in that, In step S3, the outlet of the aeration device is buried at the bottom of the heap leaching material.

6. The method for treating low-grade gold ore rich in arsenopyrite using the gold leaching reagent system for removing arsenic according to claim 1, characterized in that, In step S4, the pH-adjusting agent is dilute hydrochloric acid with a concentration of 0.1~1 mol / L, and the pH value is adjusted to 2~3.

7. A gold leaching agent system for removing arsenic, characterized in that, A method for treating low-grade gold ore rich in arsenopyrite using the gold leaching agent system for removing arsenic as described in any one of claims 1 to 6, wherein the gold leaching agent system for removing arsenic comprises ozone, glycine, cyanoacetylurea, and biotite with a purity of 98%.

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