Gold leaching agent system for removing arsenic element and method for treating low-grade gold ore rich in arsenopyrite by using gold leaching agent system

Abstract

The invention provides a gold leaching agent system for removing arsenic elements and a method for treating low-grade gold ore rich in arsenopyrite through the gold leaching agent system, and belongs to the technical field of hydrometallurgy. According to the method, ozone, glycine, cyanacetylurea and biotite with the purity being 98% are used as a gold leaching agent system, arsenic enters a slag phase from a safe ore phase through the synergistic effect of a series of agents, and it is guaranteed that a solution system only contains the gold element. The gold leaching process is simple in process and convenient to operate, compared with a traditional cyanide method, the novel agent system can effectively inhibit harmful reaction of arsenopyrite, arsenic and gold are selectively and sectionally leached, arsenic is harmless to the maximum extent by introducing the arsenic removal process, meanwhile, it is guaranteed that gold exists in a single liquid phase system, subsequent gold recovery is facilitated, and the method is suitable for industrial production. The problem of utilization of high-toxicity sand and low-gold resources is solved, the strategic requirement of sustainable development is met, and a solution is provided for treatment of high-arsenic low-grade gold ore through cyanide slow release, electrochemical catalysis and graded gold extraction.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a gold leaching agent system for removing arsenic and a method for treating low-grade gold ore rich in arsenopyrite. Background Art

[0002] Globally, easily accessible, high-grade gold resources are becoming increasingly depleted, leading to persistently tight gold supply. Against this backdrop, resources found in arsenopyrite (arsenopyrite), previously considered "dead 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 as fine particles or inclusions. Unlocking their economic value is crucial to alleviating the imbalance between gold supply and demand.

[0003] The mainstream cyanide leaching process exhibits significant inadaptability and high risks for these low-grade gold resources rich in arsenopyrite. Firstly, arsenopyrite is chemically active in the alkaline cyanidation system, consuming significant amounts of cyanide and dissolved oxygen, significantly reducing the concentration of effective gold leaching reagents. This severely interferes with and inhibits the efficient dissolution of the target gold, resulting in low gold recovery, extended leaching cycles, and dramatically increased production costs. Furthermore, and more seriously, the arsenic in arsenopyrite readily dissolves and releases during the cyanidation process, generating highly toxic soluble arsenic compounds (such as arsenite and arsenate). This not only significantly increases the difficulty and cost of subsequent harmless treatment of wastewater and waste residues, but also poses a significant threat to the ecological environment and human health. This presents formidable technical and environmental barriers to the traditional cyanidation process for treating these resources. Summary of the Invention

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

[0005] In a first aspect, the present application provides a gold leaching agent system for removing arsenic elements, wherein the gold leaching agent system for removing arsenic elements comprises ozone, glycine, cyanamide and biotite with a purity of 98%.

[0006] In the technical solution of the embodiment of the present application, by designing a gold leaching agent system to remove arsenic elements, under the oxidation action of ozone, the arsenopyrite lattice is destroyed to release the encapsulated gold, and at the same time, ozone oxidizes part of the gold into active Au. + Under the condition of introducing glycine, Fe 2+ / Fe 3+ Forms a bifunctional stable complex with glycine: On the one hand, glycine binds Fe via a carboxyl-amino bidentate coordination3+ Generate water-soluble , Fe 3+ / Fe 2+ The electrode couple realizes precise control of the redox potential of the system, catalyzes the alkaline hydrolysis of cyanoacetyl urea through electrochemical circulation, and drives the slow release efficiency of cyanide. 3+ It captures the electrons of the methylene group of cyanoacetyl urea, triggering the cleavage of the C≡N bond to generate free cyanide (CN - ), under the action of excess ozone, Fe 2+ Reoxidized to Fe 3+ Achieve electrochemical balance of the system, achieve slow release of cyanide (concentration stable at 5~10ppm), and the dissolved gold ions form [Au(CN)2] - At the same time, glycine dissolves the As released by arsenopyrite 3+ , forms a soluble chelate with the free glycine anion and enters the liquid phase, eliminating the poisoning effect of arsenic on the ferroelectric pair and promoting the continuous disintegration of the arsenopyrite lattice through the chemical dissociation (dissolution) effect, exposing the wrapped gold and promoting the deep decomposition of the arsenopyrite. Finally, the toxic element arsenic is enriched in the liquid phase. After the gold is dissolved, dilute hydrochloric acid is added to the system to adjust the pH value to acidic. The dissolved pentavalent arsenic (As 5+ ) combines with the iron ions continuously released by biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent fixation of arsenic (fixation rate > 99.5%). The gold complex is converted into a water-soluble cationic species ([Au(Cl)4] - ), stably existing in the liquid phase. Through solid-liquid separation, arsenic enters the slag phase as a safe ore phase, ensuring that the solution system contains only gold, laying the foundation for subsequent efficient gold recovery.

[0007] In a second aspect, the present application provides a method for treating low-grade gold ore rich in arsenopyrite by using a gold leaching agent system for removing arsenic, comprising the following steps: S1. Crushing low-grade gold ore rich in arsenopyrite to obtain a crushed sample; S2 was added to the crushed sample having a purity of 98% biotite, stirred, and then added to the heap leaching column to obtain a heap leaching ore; S3. A mixed solution of glycine and cyanoacetyl urea is added from the upper portion of the heap leach column to leach the heap leached ore from top to bottom. The effluent leachate is collected and pumped back to the upper portion of the heap leach column for circulated leaching. After the circulated leaching is completed, a noble solution containing gold and arsenic and leached mineral tailings are obtained. During the leaching, ozone is introduced into the leachate via an aeration device. S4. The pH value of the gold- and arsenic-containing noble solution is adjusted to obtain ferric arsenate precipitate, and then solid-liquid separation is performed to obtain a gold leaching solution.

[0008] In the technical solution of the embodiment of the present application, a method for treating low-grade gold ore rich in arsenopyrite is designed by removing the arsenic element gold leaching agent system. The above-mentioned arsenic element 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 reactions of arsenopyrite, selectively leach arsenic and gold in stages, and by introducing the arsenic removal process, the arsenic is rendered harmless to the greatest extent, while ensuring the single existence of gold in the liquid phase system, which facilitates the subsequent gold recovery, overcomes the difficult problem of high-arsenopyrite and low-gold resource utilization, and meets the strategic needs of sustainable development.

[0009] 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 particle size of the biotite with a purity of 98% is -0.074 mm and the content is 75-85%.

[0010] In this embodiment, the Fe that can be dissolved continuously from biotite is 2+ / Fe 3+ , continuously providing the ions required for the reaction in the gold immersion system.

[0011] 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 cyanoacetyl urea in the mixed solution is 1-10 g / L.

[0012] In this example, glycine binds Fe via a carboxyl-amino bidentate coordination. 3+ Generate water-soluble At the same time, glycine dissolves the As released by arsenopyrite 3+ , forming a soluble chelate with the free glycine anion and entering the liquid phase, which not only eliminates the poisoning effect of arsenic on the ferroelectric couple, but also promotes the continuous disintegration of the arsenopyrite lattice through the chemical dissociation (dissolution) effect, exposing the wrapped gold and promoting the deep decomposition of the arsenopyrite, and finally the toxic element arsenic is enriched in the liquid phase. 3+ / Fe 2+ The electrode couple realizes precise control of the redox potential of the system, catalyzes the alkaline hydrolysis of cyanoacetyl urea through electrochemical circulation, and drives the slow release efficiency of cyanide. 3+ It captures the electrons of the methylene group of cyanoacetyl urea, triggering the cleavage of the C≡N bond to generate free cyanide (CN - ), under the action of excess ozone, Fe 2+ Reoxidized to Fe 3+ Achieve electrochemical balance of the system and achieve slow release of cyanide (concentration stable at 5~10ppm).

[0013] In some embodiments, in step S3, the pH value of the mixed solution is ≥10.

[0014] In this embodiment, the gold leaching system is carried out in a strong alkaline environment to ensure that glycine exists in the form of glycine anions and that the cyanide released by cyanoacetyl urea is stably present in the solution system to prevent the generation of cyanide gas. In some embodiments, in step S3, the aeration flow rate of the ozone is 0.05~0.1m 3 / h·L.

[0015] In this embodiment, under the oxidizing effect of ozone, the arsenopyrite lattice is destroyed to release the encapsulated gold, and at the same time, ozone oxidizes part of the gold into active Au. + .

[0016] In some embodiments, in step S3, the intensity of the circulating elution is 10 L / m 2 h, the circulating elution time is 720 h, and the total volume of the mixed solution in the circulating elution is 10 L.

[0017] In this embodiment, the leaching reaction is fully carried out through the circulating elution.

[0018] In some embodiments, in step S1, the ore particle size in the crushed sample is -0.074 mm and the content is 75-85%.

[0019] In this embodiment, the sample is crushed to facilitate the subsequent leaching reaction.

[0020] In some embodiments, in step S3, the outlet of the aeration device is buried at the bottom of the heap leaching material.

[0021] In this embodiment, the aeration device is buried at the bottom, and ozone is injected directly from the bottom. Bubbles naturally move upward due to buoyancy. This creates 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 in the middle and upper areas. This is much more efficient than relying solely on top aeration or natural diffusion.

[0022] 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 adjusted is 2-3.

[0023] In this embodiment, the gold leaching solution is adjusted to acidic, and the dissolved pentavalent arsenic (As 5+ ) combines with the iron ions continuously released by biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent fixation of arsenic (fixation rate > 99.5%). The gold complex is converted into a water-soluble cationic species ([Au(Cl)4] - ), exists stably in the liquid phase.

[0024] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings used in this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0026] Figure 1 The SEM images of biotite before and after leaching and the energy spectrum of each element in biotite in the examples of this application are shown; Figure 2 The electron microscope-energy spectrum analysis diagram in the embodiment of the present application, (a) is the morphology of arsenopyrite before leaching, (b) is the morphology of arsenopyrite 24 hours after leaching, (c) is the morphology of arsenopyrite 48 hours after leaching, and (d) is the energy spectrum analysis diagram of arsenopyrite 48 hours after leaching; Figure 3 This is a schematic diagram of the process for treating low-grade gold ore rich in arsenopyrite by using the arsenic removal gold leaching agent system in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The following embodiments of the technical solution of the present application are described in detail. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only used as examples and are not intended to limit the scope of protection of the present application.

[0028] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0029] In order to solve the problems of low leaching efficiency, high cost and serious pollution of low-grade gold ore rich in arsenopyrite in existing gold leaching reagent systems, this application provides a gold leaching reagent system for removing arsenic and a method for treating low-grade gold ore rich in arsenopyrite. By designing a gold leaching reagent system for removing arsenic, under the oxidation action of ozone, the arsenopyrite crystal lattice is destroyed to release the encapsulated gold, and at the same time, ozone oxidizes part of the gold into active Au. + Under the condition of introducing glycine, Fe 2+ / Fe 3+Forms a bifunctional stable complex with glycine: On the one hand, glycine binds Fe via a carboxyl-amino bidentate coordination 3+ Generate water-soluble , Fe 3+ / Fe 2+ The electrode couple realizes precise control of the redox potential of the system, catalyzes the alkaline hydrolysis of cyanoacetyl urea through electrochemical circulation, and drives the slow release efficiency of cyanide. 3+ It captures the electrons of the methylene group of cyanoacetyl urea, triggering the cleavage of the C≡N bond to generate free cyanide (CN - ), under the action of excess ozone, Fe 2+ Reoxidized to Fe 3+ Achieve electrochemical balance of the system, achieve slow release of cyanide (concentration stable at 5~10ppm), and the dissolved gold ions form [Au(CN)2] - At the same time, glycine dissolves the As released by arsenopyrite 3+ , forms a soluble chelate with the free glycine anion and enters the liquid phase, eliminating the poisoning effect of arsenic on the ferroelectric pair and promoting the continuous disintegration of the arsenopyrite lattice through the chemical dissociation (dissolution) effect, exposing the wrapped gold and promoting the deep decomposition of the arsenopyrite. Finally, the toxic element arsenic is enriched in the liquid phase. After the gold is dissolved, dilute hydrochloric acid is added to the system to adjust the pH value to acidic. The dissolved pentavalent arsenic (As 5+ ) combines with the iron ions continuously released by biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent fixation of arsenic (fixation rate > 99.5%). The gold complex is converted into a water-soluble cationic species ([Au(Cl)4] - ), stably existing in the liquid phase. Through solid-liquid separation, arsenic enters the slag phase in a safe mineral phase, ensuring that the solution system contains only gold elements, laying the foundation for the subsequent efficient recovery of gold. This gold leaching process is simple and easy to operate. Compared with the traditional cyanide method, this new reagent system can effectively inhibit the harmful reactions of arsenopyrite, selectively leach arsenic and gold in stages, and introduce a dearsenicization process to maximize the harmlessness of arsenic. At the same time, it ensures that gold exists only in the liquid phase system, facilitating subsequent gold recovery. This overcomes the difficult problem of high-arsenopyrite and low-gold resource utilization, meets the strategic needs of sustainable development, and provides a solution for the treatment of high-arsenic, low-grade gold mines through "cyanide slow release-electrochemical catalysis-graded gold extraction."

[0030] In a first aspect, the present application provides a gold leaching agent system for removing arsenic elements, wherein the gold leaching agent system for removing arsenic elements comprises ozone, glycine, cyanamide and biotite with a purity of 98%.

[0031] In the technical solution of the embodiment of the present application, by removing the arsenic element gold leaching agent system, under the oxidation effect of ozone, the arsenopyrite lattice is destroyed to release the wrapped gold, and at the same time, ozone oxidizes part of the gold into active Au. +Under the condition of introducing glycine, Fe 2+ / Fe 3+ Forms a bifunctional stable complex with glycine: On the one hand, glycine binds Fe via a carboxyl-amino bidentate coordination 3+ Generate water-soluble , Fe 3+ / Fe 2+ The electrode couple realizes precise control of the redox potential of the system, catalyzes the alkaline hydrolysis of cyanoacetyl urea through electrochemical circulation, and drives the slow release efficiency of cyanide. 3+ It captures the electrons of the methylene group of cyanoacetyl urea, triggering the cleavage of the C≡N bond to generate free cyanide (CN - ), under the action of excess ozone, Fe 2+ Reoxidized to Fe 3+ Achieve electrochemical balance of the system, achieve slow release of cyanide (concentration stable at 5~10ppm), and the dissolved gold ions form [Au(CN)2] - At the same time, glycine dissolves the As released by arsenopyrite 3+ , forms a soluble chelate with the free glycine anion and enters the liquid phase, eliminating the poisoning effect of arsenic on the ferroelectric pair and promoting the continuous disintegration of the arsenopyrite lattice through the chemical dissociation (dissolution) effect, exposing the wrapped gold and promoting the deep decomposition of the arsenopyrite. Finally, the toxic element arsenic is enriched in the liquid phase. After the gold is dissolved, dilute hydrochloric acid is added to the system to adjust the pH value to acidic. The dissolved pentavalent arsenic (As 5+ ) combines with the iron ions continuously released by biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent fixation of arsenic (fixation rate > 99.5%). The gold complex is converted into a water-soluble cationic species ([Au(Cl)4] - ), stably existing in the liquid phase. Through solid-liquid separation, arsenic enters the slag phase as a safe ore phase, ensuring that the solution system contains only gold, laying the foundation for subsequent efficient gold recovery.

[0032] In a second aspect, the present application provides a method for treating low-grade gold ore rich in arsenopyrite by using a gold leaching agent system for removing arsenic, comprising the following steps: S1. Crushing low-grade gold ore rich in arsenopyrite to obtain a crushed sample; S2 was added to the crushed sample having a purity of 98% biotite, stirred, and then added to the heap leaching column to obtain a heap leaching ore; S3. A mixed solution of glycine and cyanoacetyl urea is added from the upper portion of the heap leach column to leach the heap leached ore from top to bottom. The effluent leachate is collected and pumped back to the upper portion of the heap leach column for circulated leaching. After the circulated leaching is completed, a noble solution containing gold and arsenic and leached mineral tailings are obtained. During the leaching, ozone is introduced into the leachate via an aeration device. S4. The pH value of the gold- and arsenic-containing noble solution is adjusted to obtain ferric arsenate precipitate, and then solid-liquid separation is performed to obtain a gold leaching solution.

[0033] In the technical solution of the embodiment of the present application, a method for treating low-grade gold ore rich in arsenopyrite is designed by removing the arsenic element gold leaching agent system. The above-mentioned arsenic element 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 reactions of arsenopyrite, selectively leach arsenic and gold in stages, and by introducing the arsenic removal process, the arsenic is rendered harmless to the greatest extent, while ensuring the single existence of gold in the liquid phase system, which facilitates the subsequent gold recovery, overcomes the difficult problem of high-arsenopyrite and low-gold resource utilization, and meets the strategic needs of sustainable development.

[0034] 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 particle size of the biotite with a purity of 98% is -0.074 mm and the content is 75-85%.

[0035] In the technical solution of the embodiment of the present application, the Fe that can be continuously dissolved from biotite 2+ / Fe 3+ , continuously providing the ions required for the reaction in the gold immersion system.

[0036] 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 cyanoacetyl urea in the mixed solution is 1-10 g / L.

[0037] In the technical solution of the embodiment of the present application, glycine binds Fe via a carboxyl-amino bidentate coordination. 3+ Generate water-soluble At the same time, glycine dissolves the As released by arsenopyrite 3+ , forming a soluble chelate with the free glycine anion and entering the liquid phase, which not only eliminates the poisoning effect of arsenic on the ferroelectric couple, but also promotes the continuous disintegration of the arsenopyrite lattice through the chemical dissociation (dissolution) effect, exposing the wrapped gold and promoting the deep decomposition of the arsenopyrite, and finally the toxic element arsenic is enriched in the liquid phase. 3+ / Fe 2+ The electrode couple realizes precise control of the redox potential of the system, catalyzes the alkaline hydrolysis of cyanoacetyl urea through electrochemical circulation, and drives the slow release efficiency of cyanide.3+ It captures the electrons of the methylene group of cyanoacetyl urea, triggering the cleavage of the C≡N bond to generate free cyanide (CN - ), under the action of excess ozone, Fe 2+ Reoxidized to Fe 3+ Achieve electrochemical balance of the system and achieve slow release of cyanide (concentration stable at 5~10ppm).

[0038] Furthermore, in some embodiments, in step S3, the pH value of the mixed solution is ≥10.

[0039] In the technical solution of the embodiment of the present application, the gold leaching system is carried out in a strongly alkaline environment to ensure that glycine exists in the form of glycine anions and the cyanide released by the slow-release cyanoacetyl urea is stably present in the solution system to prevent the generation of cyanide gas.

[0040] Furthermore, in some embodiments, in step S3, the ozone aeration flow rate is 0.05~0.1m 3 / h·L.

[0041] In the technical solution of the embodiment of the present application, under the oxidation effect of ozone, the arsenopyrite lattice is destroyed to release the wrapped gold, and at the same time, ozone oxidizes part of the gold into active Au. + .

[0042] Furthermore, in some embodiments, in step S3, the intensity of the circulating elution is 10 L / m 2 h, the circulating elution time is 720 h, and the total volume of the mixed solution in the circulating elution is 10 L.

[0043] In the technical solution of the embodiment of the present application, the leaching reaction is fully carried out through cyclic elution.

[0044] Furthermore, in some embodiments, in step S1, the ore particle size in the crushed sample is -0.074 mm and the content is 75-85%.

[0045] In the technical solution of the embodiment of the present application, the sample is crushed to facilitate the subsequent leaching reaction.

[0046] Furthermore, in some embodiments, in step S3, the outlet of the aeration device is buried at the bottom of the heap leaching material.

[0047] In the technical solution of the present embodiment, the aeration device is buried at the bottom, and ozone is injected directly from the bottom. Bubbles naturally move upward under the action of buoyancy. This creates a forced convection path throughout the entire height of the ore pile, allowing bubbles to penetrate the pore network of the ore pile and deliver ozone more evenly to all levels of the ore pile, especially in the middle and upper areas. This is much more efficient than relying solely on top aeration or natural diffusion.

[0048] 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 of the pH adjustment is 2-3.

[0049] In the technical solution of the embodiment of the present application, the gold leaching solution is adjusted to acidic, and the dissolved pentavalent arsenic (As 5+ ) combines with the iron ions continuously released by biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent fixation of arsenic (fixation rate > 99.5%). The gold complex is converted into a water-soluble cationic species ([Au(Cl)4] - ), exists stably in the liquid phase.

[0050] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used without manufacturer's indication are all commercially available conventional products.

[0051] Example 1 Example 1 provides a gold leaching agent system for removing arsenic elements, wherein the gold leaching agent system comprises ozone, glycine, cyanamide and biotite with a purity of 98%.

[0052] The above-mentioned gold leaching agent system is used to treat low-grade gold ore rich in arsenopyrite, which specifically includes the following steps: (1) Crushing low-grade gold ore rich in arsenopyrite until the ore powder with a particle size of -0.074 mm accounts for 80% of the total mass of the material to obtain a crushed sample; (2) The crushed sample was mixed evenly with biotite of the same particle size and purity of 98%, and added to a heap leaching column with a height of 1.2 m and an inner diameter of 10 cm. The heap leaching material was piled up to a height of 1 m. Among them, the biotite in the heap leaching material accounted for 7% of the mass of the crushed sample; (3) The pH value of a mixed solution of glycine with a mass concentration of 30 g / L and cyanuric acid urea with a mass concentration of 5 g / L was adjusted to 10, and then added from the upper part of the heap leaching column to leach the heap leaching material. The leaching liquid was collected and pumped to the upper part of the heap leaching column again for circulation leaching. The total volume of the mixed solution in the circulation process was 10 L, and the leaching intensity was 10 L / m 2 h, 720h of circulating leaching. During the circulating leaching process, ozone is introduced into the leachate through the aeration device, wherein the outlet of the aeration device is buried at the bottom of the heap leaching material, and the ozone explosion flow rate is 0.05m 3 / h·L. At the end of the cycle, gold- and arsenic-containing noble liquid and leaching mineral tailings are obtained; (4) Add 1 mol / L dilute hydrochloric acid to the gold and arsenic noble liquid and adjust the pH value to 2 to obtain ferric arsenate precipitate. Then separate the solid and liquid to obtain the gold leaching solution.

[0053] The sources and performance parameters of the raw materials are as follows: The low-grade gold ore rich in arsenopyrite comes from a gold mine in a mining area in Kyrgyzstan. The gold grade is 0.73g / t, and the mass of arsenic accounts for 7-14% of the total ore mass.

[0054] The gold content in the leaching tailings of each embodiment and comparative example was detected by fire assay. The test and analysis method was based on GB / T 7739 "Chemical Analysis Methods for Gold Concentrates". The gold leaching rate η is Wherein, η represents the leaching rate of gold, in units of %; m1 represents the mass of the original low-grade gold ore rich in arsenopyrite, in units of g; β1 represents the grade of the original low-grade gold ore rich in arsenopyrite, in units of g / t; m2 represents the mass of the residue after leaching of the low-grade gold ore rich in arsenopyrite, in units of g; β2 represents the grade of the residue after leaching of the low-grade gold ore rich in arsenopyrite, in units of g / t.

[0055] The gold and arsenic concentrations in the gold- and arsenic-containing noble solutions in each example and comparative example were then measured using ICP-OES. The gold leaching rate test results of the two methods were compared, and valid data were considered when the deviation between the two test results was less than 1%. Finally, the gold leaching rate for each example and comparative example was measured.

[0056] ICP-OES was used to measure the arsenic concentrations in the gold-containing and arsenic-containing noble solutions and the arsenic concentration in the gold leaching solution, and the arsenic removal rate and solidification rate were calculated respectively.

[0057] In Example 1, the arsenic solidification rate was 99.5%, and the gold complex was converted into a water-soluble cationic species ([Au(Cl)4] - ), stably exists in the liquid phase through solid-liquid separation, and arsenic enters the slag phase in the safe mineral phase, ensuring that the solution system contains only gold elements, laying the foundation for the subsequent efficient recovery of gold.

[0058] During the leaching process of Example 1, 50 mL of gold- and arsenic-containing noble solution was collected at different time points, and the cyanide concentration and iron concentration therein were detected by ICP-OES. The results are shown in Table 1.

[0059] Table 1 Concentrations of free cyanide and iron in gold and arsenic-containing noble liquors As shown in Table 1, no cyanide was added to the entire system, but the presence of free cyanide was detected, proving that cyanate urea continuously hydrolyzed in the alkaline slurry to generate free cyanide, and its concentration changed dynamically: in the early stage (36~144h): the cyanide concentration increased from 8.2mg / L to 16.3mg / L (peak), reflecting that cyanate urea gradually decomposed and released active cyanide, providing a stable coordination source for gold dissolution; in the middle stage (216~432h): the concentration was maintained at 10.5~14.2mg / L, confirming that the sustained release effect ensured the continuous gold leaching reaction; in the late stage (576~748h): the concentration dropped sharply from 10.3mg / L to 5.42mg / L, because cyanide was consumed by other dissolved metal ions and the decomposition of cyanate urea was almost complete.

[0060] After the leaching was completed, the residual solids were collected and the state of the biotite and the distribution of iron content before and after leaching were observed by SEM combined with energy spectrum analysis. Figure 1 As shown in Tables 2 and 3.

[0061] Table 2 Distribution of iron content in biotite before leaching Table 3 Distribution of iron content in biotite after leaching pass Figure 1 From Tables 2 and 3, we can see the migration pattern of iron in biotite during the reaction process. The average iron content changes from high content (14.98%) to low content (1.52%). The low iron content surface peels off, revealing a new high iron content surface. Biotite, as a source of iron, forms Fe 3+ / Fe 2+ The redox couple promotes the forward progress of gold and arsenic leaching in the reagent system. Therefore, biotite dissolves and continuously releases iron to form Fe 3+ / Fe 2+ The redox couple drives the coordinated leaching of gold and arsenic through the surface alteration and stripping mechanism, ensuring the efficient leaching of the reagent system.

[0062] In the leaching process of this embodiment, the leachate and the leaching tailings were taken at leaching time points of 6 h, 12 h, 24 h, 36 h and 48 h, and the concentrations of arsenic and iron in the leachate were tested by ICP-OES analyzer, as shown in Table 4; and the changes in the occurrence form of arsenopyrite were observed by scanning electron microscopy combined with energy spectrum analysis, as shown in Table 4. Figure 2 shown.

[0063] Table 4 Concentrations of arsenic and iron in the leachate at different time points Deep decomposition of arsenopyrite and directional removal of arsenic: Under the synergistic effect of ozone oxidation and alkaline glycine reagent, the arsenopyrite (FeAsS) lattice is directionally attacked by ozone, and the As-S bond is broken to release the encapsulated gold and arsenic species; glycine simultaneously chelates the dissolved As 3+ / As 5+ A water-soluble [As(Gly)3] complex is formed to achieve liquid phase arsenic enrichment (ICP-OES detects arsenic concentration in the precious liquid > 2000ppm), and the residual arsenic in the tailings is significantly reduced.

[0064] Evidence of arsenopyrite morphological alteration: Electron microscopy-energy spectrum analysis will show that the surface of arsenopyrite particles is honeycombed with corrosion (the original dense structure collapses), and the arsenic content in the residual arsenopyrite decreases by >90% compared with the initial value, confirming the selective dissolution ability of the ozone-glycine system for arsenopyrite.

[0065] Examples 2-3 Comparative Examples 1-2 Examples 2-3 and Comparative Examples 1-2 respectively provide a method for treating low-grade gold ore rich in arsenopyrite by using a gold leaching agent system for removing arsenic. Compared with Example 1, the difference is that the pH value of the mixed solution in step (3) is different, as shown in Table 5. The other steps are substantially the same as those in Example 1 and will not be repeated here.

[0066] Table 5 pH value of the mixed solution and the gold leaching rate and arsenic removal rate in Examples 1 to 3 and Comparative Examples 1 to 2 Table 5 shows that the pH of the mixed solution significantly affects the gold leaching rate and arsenic removal rate. When the pH is ≥10, the system can efficiently leach gold (≥92%) and simultaneously achieve deep arsenic removal (≥95%). However, if the pH is ≤9 (Comparative Examples 1-2), the gold leaching rate drops sharply (≤7%). Although the arsenic removal rate can reach 92% at pH 9, gold is almost completely leached at this point.

[0067] Examples 4-5 and Comparative Examples 3-4 Examples 4-5 and Comparative Examples 3-4 respectively provide a method for treating low-grade gold ore rich in arsenopyrite by using a gold leaching agent system for removing arsenic. Compared with Example 1, the difference is that the mass concentration of glycine in step (3) is different, as shown in Table 6. The other steps are substantially the same as those in Example 1 and are not described again here.

[0068] Table 6 Mass concentration of glycine and gold leaching rate and arsenic removal rate in Examples 4-5 and Comparative Examples 3-4 Table 6 shows that glycine concentration significantly regulates arsenic-gold leaching 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%). Excessive glycine, while maintaining a high arsenic removal rate, can compromise the gold leaching rate. This suggests that sufficient glycine can fully chelate the high-valent arsenic produced by ozone oxidation of arsenopyrite, forming a stable water-soluble complex that prevents arsenic from re-coating gold particles. However, when the glycine content is too low, while ozone can partially oxidize the arsenopyrite to release arsenic (gold leaching rate of 79%), the arsenic removal rate plummets to 32%, demonstrating that glycine chelates oxidized arsenic to form a stable water-soluble complex, preventing arsenic re-adsorption or precipitation.

[0069] Examples 6-7 and Comparative Examples 5-6 Examples 6-7 and Comparative Examples 5-6 respectively provide a method for treating low-grade gold ore rich in arsenopyrite by using a gold leaching agent system for removing arsenic. Compared with Example 1, the difference is that the mass concentration of cyanoacetyl urea in step (3) is different, as shown in Table 7. The other steps are substantially the same as those in Example 1 and are not described in detail here.

[0070] Table 7 Mass concentration of cyanurate and gold leaching rate and arsenic removal rate in Examples 6-7 and Comparative Examples 5-6 As can be seen from Table 7, the concentration of cyanoacetyl urea has a significant threshold effect on the gold leaching rate, while the arsenic removal rate remains stable. As a slow-release free cyanide release agent, cyanoacetyl urea needs to reach a critical value (≥1 g / L) in order to efficiently dissolve gold. When the concentration of cyanoacetyl urea 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 in the reaction pathway.

[0071] Examples 8-9 and Comparative Examples 7-8 Examples 8-9 and Comparative Examples 7-8 respectively provide a method for treating low-grade gold ore rich in arsenopyrite by using a gold leaching agent system for removing arsenic. Compared with Example 1, the difference is that the ozone explosion flow rate in step (3) is different, as shown in Table 8. The other steps are roughly the same as those in Example 1 and will not be repeated here.

[0072] Table 8 Ozone explosion flow rate and gold leaching rate and arsenic removal rate in Examples 8-9 and Comparative Examples 7-8 It can be seen from Table 8 that the ozone explosion flow rate significantly affects the gold-arsenic separation efficiency by regulating the degree of mineral oxidation: when the flow rate is ≥0.05m 3 / h·L, the gold leaching rate is ≥92%, and the arsenic removal rate is ≥95%; when the ozone explosion flow rate continues to increase, the gold leaching rate and the arsenic removal rate remain basically unchanged. This is because the sufficient ozone explosive airflow can completely destroy the arsenopyrite mineral lattice, release the encapsulated fine gold particles, and fully oxidize arsenic and gold to a high valence state, promote the efficient chelation of arsenic by glycine, and slowly decompose cyanide urea into cyanide to react with gold ions, which is also beneficial to the balance of the divalent iron / trivalent iron couple in biotite and the circulation of the catalytic system; when the ozone explosion flow rate is too small, the gold leaching rate is only 49% (much lower than 92% in Example 1), which confirms that ozone destroys the arsenopyrite mineral lattice through explosive oxidation, releases the encapsulated fine gold particles, and converts gold into a high valence ion.

[0073] Examples 10-11 and Comparative Examples 9-10 Examples 10-11 and Comparative Examples 9-10 respectively provide a method for treating low-grade gold ore rich in arsenopyrite by using a gold leaching agent system for removing arsenic. Compared with Example 1, the difference is that the mass fraction of biotite in step (3) is different, as shown in Table 9. The other steps are substantially the same as those in Example 1 and are not described again here.

[0074] Table 9 Mass fraction of biotite and gold leaching rate and arsenic extraction rate in Examples 10-11 and Comparative Examples 9-10 It can be seen from Table 9 that when the mass fraction of biotite is 5-10%, its ferroelectric pair catalyzes and promotes the slow-release decomposition of cyanoacetyl urea, with a gold leaching rate ≥90% and an arsenic removal rate ≥95%. When the ratio is lower than 5%, the redox electron density of the ferroelectric pair is insufficient, making it difficult to regulate the pair balance through charge transfer, thus affecting the leaching of gold and the removal of arsenic. When the ratio is higher than 10%, no further improvement is achieved.

[0075] In summary, this application provides a gold leaching agent system for removing arsenic and a method for treating low-grade gold ore rich in arsenopyrite. Figure 3 As shown, by designing a gold leaching agent system to remove arsenic elements, under the oxidation effect of ozone, the arsenopyrite lattice is destroyed to release the encapsulated gold, and at the same time, ozone oxidizes part of the gold into active Au. + Under the condition of introducing glycine, Fe 2+ / Fe 3+ Forms a bifunctional stable complex with glycine: On the one hand, glycine binds Fe via a carboxyl-amino bidentate coordination 3+ Generate water-soluble , Fe 3+ / Fe 2+ The electrode couple realizes precise control of the redox potential of the system, catalyzes the alkaline hydrolysis of cyanoacetyl urea through electrochemical circulation, and drives the slow release efficiency of cyanide.3+ It captures the electrons of the methylene group of cyanoacetyl urea, triggering the cleavage of the C≡N bond to generate free cyanide (CN - ), under the action of excess ozone, Fe 2+ Reoxidized to Fe 3+ Achieve electrochemical balance of the system, achieve slow release of cyanide (concentration stable at 5~10ppm), and the dissolved gold ions form [Au(CN)2] - At the same time, glycine dissolves the As released by arsenopyrite 3+ , forms a soluble chelate with the free glycine anion and enters the liquid phase, eliminating the poisoning effect of arsenic on the ferroelectric pair and promoting the continuous disintegration of the arsenopyrite lattice through the chemical dissociation (dissolution) effect, exposing the wrapped gold and promoting the deep decomposition of the arsenopyrite. Finally, the toxic element arsenic is enriched in the liquid phase. After the gold is dissolved, dilute hydrochloric acid is added to the system to adjust the pH value to acidic. The dissolved pentavalent arsenic (As 5+ ) combines with the iron ions continuously released by biotite to form a stable ferric arsenate (FeAsO4) precipitate, achieving permanent fixation of arsenic (fixation rate > 99.5%). The gold complex is converted into a water-soluble cationic species ([Au(Cl)4] - ), stably existing in the liquid phase. Through solid-liquid separation, arsenic enters the slag phase in a safe mineral phase, ensuring that the solution system contains only gold elements, laying the foundation for the subsequent efficient recovery of gold. This gold leaching process is simple and easy to operate. Compared with the traditional cyanide method, this new reagent system can effectively inhibit the harmful reactions of arsenopyrite, selectively leach arsenic and gold in stages, and introduce a dearsenicization process to maximize the harmlessness of arsenic. At the same time, it ensures that gold exists only in the liquid phase system, facilitating subsequent gold recovery. This overcomes the difficult problem of high-arsenopyrite and low-gold resource utilization, meets the strategic needs of sustainable development, and provides a solution for the treatment of high-arsenic, low-grade gold mines through "cyanide slow release-electrochemical catalysis-graded gold extraction."

[0076] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A gold leaching agent system for removing arsenic, characterized in that: The arsenic removal and gold leaching agent system comprises ozone, glycine, cyanamide and biotite with a purity of 98%.

2. A method for treating low-grade gold ore rich in arsenopyrite by using a gold leaching agent system for removing arsenic, characterized in that: The gold leaching process using the arsenic removal gold leaching agent system according to claim 1 comprises the following steps: S1. Crushing low-grade gold ore rich in arsenopyrite to obtain a crushed sample; S2 was added to the crushed sample having a purity of 98% biotite, stirred, and then added to the heap leaching column to obtain a heap leaching ore; S3. A mixed solution of glycine and cyanoacetyl urea is added from the upper portion of the heap leach column to leach the heap leached ore from top to bottom. The effluent leachate is collected and pumped back to the upper portion of the heap leach column for circulated leaching. After the circulated leaching is completed, a noble solution containing gold and arsenic and leached mineral tailings are obtained. During the leaching, ozone is introduced into the leachate via an aeration device. S4. The pH value of the gold- and arsenic-containing noble solution is adjusted to obtain ferric arsenate precipitate, and then solid-liquid separation is performed to obtain a gold leaching solution.

3. The method for treating low-grade gold ore rich in arsenopyrite by using the arsenic removal gold leaching agent system according to claim 2, characterized in that: In step S2, the biotite with a purity of 98% accounts for 5-10% of the mass of the crushed sample, and the particle size of the biotite with a purity of 98% is -0.074 mm and the content is 75-85%.

4. The method for treating low-grade gold ore rich in arsenopyrite by using the arsenic removal gold leaching agent system according to claim 2, characterized in that: In step S3, the mass concentration of glycine in the mixed solution is 10-50 g / L, and the mass concentration of cyanoacetyl urea in the mixed solution is 1-10 g / L.

5. The method for treating low-grade gold ore rich in arsenopyrite by using the arsenic removal gold leaching agent system according to claim 2, characterized in that: In step S3, the pH value of the mixed solution is ≥10.

6. The method for treating low-grade gold ore rich in arsenopyrite by using the arsenic removal gold leaching agent system according to claim 2, characterized in that: In step S3, the ozone aeration flow rate is 0.05~0.1m 3 / h·L.

7. The method for treating low-grade gold ore rich in arsenopyrite by using the arsenic removal gold leaching agent system according to claim 2, characterized in that: In step S3, the intensity of the circulating elution is 10L / m 2 h, the circulating elution time is 720 h, and the total volume of the mixed solution in the circulating elution is 10 L.

8. The method for treating low-grade gold ore rich in arsenopyrite by using the arsenic removal gold leaching agent system according to claim 2, characterized in that: In step S1, the ore particle size in the crushed sample is -0.074 mm and the content is 75-85%.

9. The method for treating low-grade gold ore rich in arsenopyrite by using the arsenic removal gold leaching agent system according to claim 2, characterized in that: In step S3, the outlet of the aeration device is buried at the bottom of the heap leaching material.

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

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