A process for gold extraction by intensified alkaline leaching pretreatment with reduced sodium cyanide consumption

Abstract

The application discloses a kind of gold extraction processes of reinforced alkali leaching pretreatment for reducing sodium cyanide consumption, it is related to metallurgical technical field, including the following steps: the tellurium-containing gold material is mixed with water, and the treated slurry is obtained;Sodium hydroxide is added to the treated slurry, and the pH of the treated slurry is adjusted, so that the treated slurry is in alkaline conditions;Sodium sulfide is added to the treated slurry in alkaline conditions, and alkali leaching pretreatment is carried out, so that at least part of the tellurium-containing components on the surface of the tellurium-containing gold material are converted into dissolved tellurium-containing species and enter the alkali leaching solution;The application adds and continuously stirs the separable tellurium-containing species adsorption particles during the alkali leaching pretreatment stage, so that the dissolved tellurium-containing species in the alkali leaching solution are synchronously adsorbed and removed, thereby promoting the tellurium-containing gold material surface to continue to dissolve the tellurium-containing cover layer, and to form a gold exposed surface that is more easily leached by cyanide before cyanidation.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, specifically to an enhanced alkaline leaching pretreatment gold extraction process that reduces sodium cyanide consumption. Background Technology

[0002] Tellurium-bearing gold materials are a special type of gold ore resource, where gold can exist as native gold, tellurized gold, tellurium-silver gold, or tellurium-bearing associated mineral phases. For this type of material, the industrial process typically combines alkaline pretreatment with cyanide leaching. First, the material is pretreated under alkaline conditions, allowing some associated components to enter the liquid phase or undergo surface transformation. Then, the pretreated solid material is subjected to cyanide leaching to obtain a gold-bearing leachate for further gold recovery.

[0003] In tellurium gold concentrate, tellurium gold tailings, or tellurium gold sulfide materials, conventional alkaline leaching pretreatment can allow some tellurium components to enter the alkaline leaching solution. However, as the concentration of dissolved tellurium species in the alkaline leaching solution increases, the tellurium hydration layer or tellurium oxide layer on the gold telluride surface tends to remain, causing the subsequent cyanidation leaching stage to rely on higher sodium cyanide concentrations, longer leaching times, or stronger alkalinity to break through this surface coating. This results in high sodium cyanide consumption and unstable gold leaching rates under low cyanide conditions. Therefore, there is a need in the art for an enhanced alkaline leaching pretreatment gold extraction process that can weaken the tellurium surface coating before cyanidation and reduce the ineffective consumption of subsequent sodium cyanide. Summary of the Invention

[0004] The purpose of this invention is to provide an enhanced alkaline leaching pretreatment gold extraction process that reduces sodium cyanide consumption, thereby solving the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an enhanced alkaline leaching pretreatment gold extraction process that reduces sodium cyanide consumption, comprising the following steps: The tellurium-containing material is mixed with water to obtain the slurry to be processed; Sodium hydroxide is added to the slurry to be treated to adjust the pH of the slurry and make it alkaline. Sodium sulfide is added to the slurry to be treated under alkaline conditions for alkaline leaching pretreatment, so that at least part of the tellurium-containing components on the surface of the tellurium-containing gold material are converted into dissolved tellurium-containing species and enter the alkaline leaching solution. During the alkaline leaching pretreatment process, tellurium-containing species adsorption particles are added, and the slurry to be treated is continuously stirred so that the tellurium-containing species adsorption particles come into contact with the alkaline leaching solution to adsorb dissolved tellurium-containing species in the alkaline leaching solution. By adsorbing the dissolved tellurium species by the tellurium species adsorption particles, the concentration of dissolved tellurium species in the alkaline leaching solution is reduced, allowing the tellurium-containing coating layer on the surface of the tellurium-containing gold material to continue dissolving into the alkaline leaching solution, thus obtaining a pretreated slurry. The tellurium-containing species adsorbed particles are separated from the pretreated slurry to obtain a pretreated slurry after the tellurium-containing species adsorbed particles have been removed. The pretreated slurry after removing the adsorbed particles containing tellurium species is subjected to solid-liquid separation and washing to obtain the pretreated solid material. Sodium cyanide was added to the pretreated solid material to perform cyanide leaching, resulting in a gold-containing leachate. The dissolved tellurium species are tellurium-containing anions or tellurium-containing oxygen anions that enter the alkaline leaching solution during the alkaline leaching pretreatment of the tellurium-containing gold material; the tellurium-containing species adsorbent particles are particulate materials that maintain a solid particle morphology under alkaline conditions and are capable of adsorbing the dissolved tellurium species.

[0006] According to the above technical solution, the tellurium-containing gold material is tellurium-containing gold concentrate, tellurium-containing gold tailings, or tellurium-containing gold sulfide material, wherein the tellurium-containing gold material contains at least one of gold telluride, silver-gold telluride, and lead telluride associated phases; the tellurium-containing capping layer is a tellurium-containing hydration layer, a tellurium-containing oxide layer, or a tellurium-containing sulfide conversion layer formed on the surface of the tellurium-containing gold material particles, wherein the tellurium-containing capping layer covers the outside of the gold exposure site and prevents subsequent contact between sodium cyanide and gold.

[0007] According to the above technical solution, the tellurium-containing species adsorption particles include at least one of magnesium-aluminum layered hydroxide particles, magnesium-aluminum composite oxide particles, iron oxide particles, and iron hydroxide particles; or, the tellurium-containing species adsorption particles include a particle matrix and a tellurium-containing species adsorption layer disposed on the surface of the particle matrix, wherein the particle matrix is ​​used to maintain the tellurium-containing species adsorption particles in a separable particle morphology, and the tellurium-containing species adsorption layer is used to contact and adsorb the dissolved tellurium-containing species.

[0008] According to the above technical solution, the particle matrix is ​​a magnetic particle matrix, and the tellurium-containing species adsorbed particles are separated from the pretreated slurry by magnetic separation; or, the particle matrix is ​​a large-particle-size inert particle matrix, and the particle size of the tellurium-containing species adsorbed particles is larger than the average particle size of the mineral particles formed after grinding the tellurium-containing gold material, and the tellurium-containing species adsorbed particles are separated from the pretreated slurry by screening or sedimentation classification.

[0009] According to the above technical solution, during the alkaline leaching pretreatment, the pH of the slurry to be treated is maintained above pH 12, so that the tellurium-containing components are converted into dissolved tellurium-containing species under alkaline conditions; and, sodium hydroxide is added first and stirred to make the slurry to be treated reach alkaline conditions before adding sodium sulfide, so as to reduce the ineffective decomposition of sodium sulfide under non-alkaline conditions.

[0010] According to the above technical solution, the tellurium-containing species adsorbent particles undergo alkali pre-wetting and washing treatment before being added to the slurry to be treated. The alkali pre-wetting treatment is used to remove air from the pores of the tellurium-containing species adsorbent particles and to ensure that the tellurium-containing species adsorbent particles can fully contact the alkali leaching solution after entering the slurry to be treated. The washing treatment is used to remove soluble impurities from the surface of the tellurium-containing species adsorbent particles to reduce the entry of soluble impurities into the subsequent cyanide leaching stage.

[0011] According to the above technical solution, the tellurium-containing species adsorption particles are added to the slurry to be treated after the sodium sulfide is added, so that the tellurium-containing components on the surface of the tellurium-containing gold material are first converted into dissolved tellurium-containing species, and then the dissolved tellurium-containing species are adsorbed by the tellurium-containing species adsorption particles; or, the tellurium-containing species adsorption particles are added to the slurry to be treated in batches, with the next batch of tellurium-containing species adsorption particles added after the previous batch of tellurium-containing species adsorption particles adsorbed the dissolved tellurium-containing species, so as to maintain the adsorption capacity of the alkaline leaching solution for the dissolved tellurium-containing species.

[0012] According to the above technical solution, during the alkaline leaching pretreatment process, the concentration of dissolved tellurium in the alkaline leaching solution is detected, and the completion of the alkaline leaching pretreatment is determined based on the concentration of dissolved tellurium. The alkaline leaching pretreatment ends when the change in the concentration of dissolved tellurium obtained from two consecutive detections is less than a preset change; or, the alkaline leaching pretreatment ends when the concentration of dissolved tellurium in the alkaline leaching solution decreases after the addition of the tellurium-containing adsorbent particles and remains stable after continued stirring. Before cyanide leaching, the tellurium content on the surface of the pretreated solid material or the dissolved tellurium concentration in the corresponding washing solution is detected. When the tellurium content on the surface of the pretreated solid material is lower than the preset tellurium content, or the dissolved tellurium concentration in the washing solution is lower than the preset tellurium concentration in the washing solution, the cyanide leaching step is initiated. After the alkaline leaching pretreatment, the tellurium-containing coating thickness on the surface of the pretreated solid material is less than the tellurium-containing coating thickness on the surface of the tellurium-containing gold material before the alkaline leaching pretreatment.

[0013] According to the above technical solution, the step of separating the tellurium-containing species adsorbent particles from the pretreated slurry is completed before the cyanide leaching to prevent the tellurium-containing species adsorbent particles from entering the cyanide leaching system and adsorbing gold-cyanide complexes; the washing includes washing the pretreated solid material with clean water or dilute alkali solution at least once to reduce the content of residual dissolved tellurium-containing species in the pretreated solid material; the amount of tellurium-containing species adsorbent particles added is determined according to the tellurium content in the tellurium-containing gold material, so that the adsorption capacity of the tellurium-containing species adsorbent particles for the dissolved tellurium-containing species is greater than the amount of dissolved tellurium-containing species released by the tellurium-containing gold material during the alkali leaching pretreatment.

[0014] According to the above technical solution, the cyanide leaching includes the following steps: mixing the pretreated solid material with water to obtain a cyanide slurry; adjusting the pH of the cyanide slurry to place it under alkaline cyanidation conditions; adding sodium cyanide to the cyanide slurry and introducing air or oxygen to allow gold in the pretreated solid material to enter the liquid phase, obtaining the gold-containing leaching solution; the cyanide leaching is carried out after the tellurium-containing capping layer has been weakened by the alkaline leaching pretreatment, allowing the sodium cyanide to react with the pretreated solid material. The gold in the solid material is exposed on the surface and forms a gold-cyanide complex. The separated tellurium-containing species adsorbed particles are washed and then regenerated. The regeneration process is used to remove the tellurium-containing species adsorbed on the tellurium-containing species adsorbed particles and to reuse the tellurium-containing species adsorbed particles for the alkaline leaching pretreatment of the next batch of tellurium-containing gold material. The regeneration process includes eluting the tellurium-containing species adsorbed particles with alkaline solution, salt solution or alkaline salt solution to obtain tellurium-containing eluent and regenerated tellurium-containing species adsorbed particles.

[0015] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: By simultaneously removing dissolved tellurium species in the alkaline leaching solution during the alkaline leaching pretreatment stage, the dissolution process of the tellurium-containing coating layer continues, reducing the retention of the tellurium-containing hydration layer or tellurium-containing oxide layer on the gold surface. This reduces the sodium cyanide consumption required to destroy the coating layer during the subsequent cyanidation stage from the source. Since the tellurium-containing species adsorbed particles are separated before cyanidation, they are prevented from adsorbing gold-cyanide complexes or interfering with the gold leaching process after entering the cyanidation system, thereby improving the gold leaching stability of tellurium-containing gold materials with a lower sodium cyanide dosage. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1 The present invention provides a technical solution: an enhanced alkaline leaching pretreatment gold extraction process that reduces sodium cyanide consumption, comprising the following steps: The tellurium-containing material is mixed with water to obtain the slurry to be processed; Sodium hydroxide is added to the slurry to adjust its pH to make it alkaline. Sodium sulfide is added to the slurry to be treated under alkaline conditions for alkaline leaching pretreatment, so that at least part of the tellurium-containing components on the surface of the tellurium-containing gold material are converted into dissolved tellurium-containing species and enter the alkaline leaching solution. During the alkaline leaching pretreatment process, tellurium-containing species adsorption particles are added and the slurry to be treated is continuously stirred so that the tellurium-containing species adsorption particles come into contact with the alkaline leaching solution to adsorb the dissolved tellurium-containing species in the alkaline leaching solution. By adsorbing dissolved tellurium species by tellurium species adsorption particles, the concentration of dissolved tellurium species in the alkaline leaching solution is reduced, allowing the tellurium-containing coating layer on the surface of tellurium-containing gold material to continue to dissolve into the alkaline leaching solution, thus obtaining a pretreated slurry. Tellurium-containing adsorbed particles are separated from the pretreated slurry to obtain the pretreated slurry after the tellurium-containing adsorbed particles have been removed. The pretreated slurry, after removing adsorbed particles containing tellurium species, was subjected to solid-liquid separation and washing to obtain the pretreated solid material. Sodium cyanide was added to the pretreated solid material for cyanide leaching to obtain a gold-containing leachate. Among them, dissolved tellurium species are tellurium-containing anions or tellurium-containing oxygen anions that enter the alkaline leaching solution during the alkaline leaching pretreatment of tellurium-containing gold materials; tellurium-containing species adsorbent particles are particulate materials that maintain a solid particle morphology under alkaline conditions and can adsorb dissolved tellurium species. The tellurium-containing gold material is tellurium-containing gold concentrate, tellurium-containing gold tailings, or tellurium-containing gold sulfide material. The tellurium-containing gold material contains at least one of the following associated phases: gold telluride, silver-gold telluride, and lead telluride. The tellurium-containing capping layer is a tellurium-containing hydration layer, a tellurium-containing oxide layer, or a tellurium-containing sulfide conversion layer formed on the surface of the tellurium-containing gold material particles. The tellurium-containing capping layer covers the outside of the gold exposure site and prevents subsequent contact between sodium cyanide and gold. The tellurium-containing species adsorption particles include at least one of magnesium-aluminum layered hydroxide particles, magnesium-aluminum composite oxide particles, iron oxide particles, and iron hydroxide particles; or, the tellurium-containing species adsorption particles include a particle matrix and a tellurium-containing species adsorption layer disposed on the surface of the particle matrix, wherein the particle matrix is ​​used to maintain the tellurium-containing species adsorption particles in a separable particle morphology, and the tellurium-containing species adsorption layer is used to contact and adsorb dissolved tellurium-containing species. The particle matrix is ​​a magnetic particle matrix, and tellurium-containing species adsorbed particles are separated from the pretreated slurry by magnetic separation; or, the particle matrix is ​​a large-particle-size inert particle matrix, and the particle size of the tellurium-containing species adsorbed particles is larger than the average particle size of the mineral particles formed after grinding the tellurium-containing gold material, and the tellurium-containing species adsorbed particles are separated from the pretreated slurry by screening or sedimentation classification. During alkaline leaching pretreatment, the pH of the slurry to be treated is maintained above 12, so that the tellurium-containing components are converted into dissolved tellurium-containing species under alkaline conditions. Furthermore, sodium hydroxide is added first and stirred to bring the slurry to be treated to alkaline conditions before adding sodium sulfide to reduce the ineffective decomposition of sodium sulfide under non-alkaline conditions. Before being added to the slurry to be treated, the tellurium-containing adsorbent particles undergo alkali pre-wetting and washing treatment. The alkali pre-wetting treatment is used to remove air from the pores of the tellurium-containing adsorbent particles and to ensure that the tellurium-containing adsorbent particles can fully contact the alkali leaching solution after entering the slurry to be treated. The washing treatment is used to remove soluble impurities from the surface of the tellurium-containing adsorbent particles to reduce the amount of soluble impurities entering the subsequent cyanide leaching stage. Tellurium-containing species adsorbent particles are added to the slurry to be treated after sodium sulfide is added. This allows the tellurium-containing components on the surface of the tellurium-containing gold material to first be converted into dissolved tellurium-containing species, which are then adsorbed by the tellurium-containing species adsorbent particles. Alternatively, tellurium-containing species adsorbent particles are added to the slurry to be treated in batches, with the next batch added after the previous batch has adsorbed the dissolved tellurium-containing species, in order to maintain the adsorption capacity of the alkaline leaching solution for dissolved tellurium-containing species. During the alkaline leaching pretreatment, the concentration of dissolved tellurium in the alkaline leaching solution is detected, and the completion of the alkaline leaching pretreatment is determined based on the dissolved tellurium concentration. The alkaline leaching pretreatment ends when the change in dissolved tellurium concentration between two consecutive detections is less than a preset change. Alternatively, the alkaline leaching pretreatment ends when the dissolved tellurium concentration in the alkaline leaching solution decreases after the addition of tellurium-containing adsorbent particles and remains stable after continued stirring. Before cyanide leaching of the pretreated solid material, the tellurium content on the surface of the pretreated solid material or the dissolved tellurium concentration in the corresponding washing solution is detected. The cyanide leaching step begins when the tellurium content on the surface of the pretreated solid material is lower than a preset tellurium content, or the dissolved tellurium concentration in the washing solution is lower than a preset tellurium concentration in the washing solution. After the alkaline leaching pretreatment, the tellurium-containing coating thickness on the surface of the pretreated solid material is less than the tellurium-containing coating thickness on the surface of the tellurium-containing gold material before the alkaline leaching pretreatment.

[0019] The step of separating tellurium-containing species adsorbent particles from the pretreated slurry is completed before cyanide leaching to prevent tellurium-containing species adsorbent particles from entering the cyanide leaching system and adsorbing gold-cyanide complexes. Washing includes washing the pretreated solid material with clean water or dilute alkali solution at least once to reduce the content of residual dissolved tellurium-containing species in the pretreated solid material. The amount of tellurium-containing species adsorbent particles added is determined according to the tellurium content in the tellurium-containing gold material, so that the adsorption capacity of the tellurium-containing species adsorbent particles for dissolved tellurium-containing species is greater than the amount of dissolved tellurium-containing species released by the tellurium-containing gold material during the alkali leaching pretreatment.

[0020] Cyanide leaching includes the following steps: mixing pretreated solid materials with water to obtain cyanide slurry; adjusting the pH of the cyanide slurry to place it under alkaline cyanidation conditions; adding sodium cyanide to the cyanide slurry and introducing air or oxygen to allow gold in the pretreated solid materials to enter the liquid phase, obtaining a gold-containing leaching solution; cyanide leaching is carried out after the tellurium-containing capping layer has been weakened by alkaline leaching pretreatment, allowing sodium cyanide to contact the exposed gold surface in the pretreated solid materials and form a gold-cyanide complex; the separated tellurium-containing species adsorbed particles are washed and then regenerated. The regeneration treatment is used to remove tellurium-containing species adsorbed on the tellurium-containing species adsorbed particles and to reuse the tellurium-containing species adsorbed particles for the alkaline leaching pretreatment of the next batch of tellurium-containing gold materials; the regeneration treatment includes eluting the tellurium-containing species adsorbed particles with alkaline solution, salt solution, or alkaline salt solution to obtain a tellurium-containing eluent and regenerated tellurium-containing species adsorbed particles.

[0021] In this embodiment, tellurium-containing gold material refers to gold mineral material in which gold and tellurium coexist, specifically tellurium-containing gold concentrate, tellurium-containing gold tailings, or tellurium-containing gold sulfide material. The gold in the tellurium-containing gold material can exist in the form of native gold, gold telluride, tellurium-silver-gold, or tellurium-lead associated phases. When this type of material is directly subjected to cyanide leaching, a tellurium hydration layer, a tellurium oxide layer, or a tellurium sulfide conversion layer easily forms on the surface of the tellurium-containing mineral phase. This tellurium capping layer hinders the contact between sodium cyanide and the exposed gold sites, causing a portion of the sodium cyanide to be consumed in the process of destroying the surface capping layer and side reactions, resulting in an increase in the amount of sodium cyanide used.

[0022] The slurry to be treated is obtained by mixing tellurium-gold material with water. The tellurium-gold material can be first crushed and ground to fully expose the gold mineral particles, tellurium-bearing mineral particles, and their associated particles. The particle size of the ground mineral particles can be determined based on the efficiency of subsequent solid-liquid separation and alkaline leaching. As long as the surface of the tellurium-bearing mineral is in sufficient contact with the alkaline leaching solution, it is not required to grind all mineral particles to an extremely fine state, so as to avoid over-grinding leading to mud formation and affecting the subsequent separation of adsorbed particles.

[0023] The purpose of adding sodium hydroxide is to create a stable alkaline environment for subsequent sodium sulfide leaching. Maintaining the pH of the slurry to be treated above 12 reduces the ineffective decomposition of sodium sulfide under non-alkaline conditions and facilitates the conversion of tellurium-containing components into soluble tellurium-containing species that can enter the liquid phase in the alkaline system. The pH can be obtained using an online pH meter or by sampling and is maintained by adding sodium hydroxide.

[0024] Upon addition of sodium sulfide, some tellurium-containing components on the surface of tellurium-containing gold materials undergo transformation under alkaline conditions and enter the alkaline leaching solution as dissolved tellurium species. These dissolved tellurium species include tellurium anions or tellurium oxyanions, such as tellurite, tellurate, or other tellurium-containing ion forms that can migrate in the alkaline liquid phase, formed from the transformation of tellurium-containing mineral surfaces. If these dissolved tellurium species are not removed promptly after entering the alkaline leaching solution, they will increase the tellurium concentration in the solution, thereby reducing the tendency for the tellurium-containing capping layer to continue dissolving.

[0025] The tellurium-containing species adsorbent particles are used to adsorb dissolved tellurium-containing species in the alkaline leaching solution during the alkaline leaching pretreatment stage. The tellurium-containing species adsorbent particles should meet two conditions: first, they should maintain a solid particle form in the alkaline slurry and not completely dissolve due to stirring and alkaline leaching conditions; second, they should be able to contact and adsorb dissolved tellurium-containing species in the alkaline leaching solution. The tellurium-containing species adsorbent particles can be one or more of magnesium-aluminum layered hydroxide particles, magnesium-aluminum composite oxide particles, iron oxide particles, and iron hydroxide particles, or particles formed by combining a particle matrix with a tellurium-containing species adsorption layer.

[0026] In one embodiment, the tellurium-containing species adsorbent particles comprise a particle matrix and a tellurium-containing species adsorption layer disposed on the surface of the particle matrix. The particle matrix primarily provides a separable particle morphology, enabling the adsorbent particles to be removed from the slurry after alkaline leaching via magnetic separation, sieving, or sedimentation. The tellurium-containing species adsorption layer primarily provides adsorption sites, allowing dissolved tellurium-containing species to transfer from the alkaline leaching solution to the surface of the adsorbent particles. With this structure, adsorption and separation functions are simultaneously performed by the same particle, avoiding the addition of difficult-to-recover powdered adsorbent to the slurry system.

[0027] When a magnetic particle matrix is ​​used, the tellurium-containing species adsorbed particles can be recovered by magnetic separation after alkaline leaching. When a large-particle-size inert particle matrix is ​​used, the particle size of the tellurium-containing species adsorbed particles is larger than the average particle size of the mineral particles formed after grinding the tellurium-containing gold material, so that they can be separated by sieving or sedimentation classification. The average particle size of the mineral particles can be obtained by sieving or laser particle size analysis, and the particle size of the adsorbed particles is selected based on this average particle size to ensure a separable particle size difference between the adsorbed particles and the mineral particles.

[0028] The tellurium-containing adsorbent particles can be pre-wetted with an alkaline solution before being added. Alkaline pre-wetting involves contacting the tellurium-containing adsorbent particles with an alkaline solution to expel air from the pores and wet the surface of the particles. After pre-wetting, the adsorbent particles are less likely to float or agglomerate due to air bubbles when they enter the slurry, allowing them to disperse more stably in the slurry and contact the alkaline leaching solution. The tellurium-containing adsorbent particles can also be washed before addition to remove soluble impurities from their surface, reducing the likelihood of these impurities entering the subsequent cyanide leaching stage.

[0029] Regarding the order of addition, sodium hydroxide can be added to the slurry to be treated first and stirred to bring the slurry to alkaline conditions before adding sodium sulfide. After the sodium sulfide is added and begins to transfer the tellurium-containing components into the alkaline leaching solution, tellurium-containing species adsorbent particles are then added. When the above addition order is adopted, the tellurium-containing components on the surface of the tellurium-containing minerals are first transformed in the alkaline sulfide system, and then the adsorbent particles adsorb the dissolved tellurium-containing species that have entered the alkaline leaching solution, thereby maintaining a low concentration of dissolved tellurium-containing species in the alkaline leaching solution.

[0030] In another embodiment, tellurium-containing species adsorbent particles can be added to the slurry to be treated in batches. After one batch of tellurium-containing species adsorbent particles adsorbs a certain amount of dissolved tellurium-containing species, another batch of tellurium-containing species adsorbent particles is added, so that the alkaline leaching solution always retains effective adsorption capacity. The batch addition method is particularly suitable for materials with high tellurium content or materials where the release of tellurium-containing species during alkaline leaching is prolonged, and can prevent the adsorbent particles added at once from approaching adsorption saturation too early.

[0031] The amount of tellurium-containing species adsorbent particles added can be determined based on the tellurium content in the tellurium-containing gold material. Specifically, the tellurium content in the tellurium-containing gold material can be detected first, and then, combined with the release ratio of dissolved tellurium-containing species in a small-scale alkaline leaching test, the total amount of tellurium-containing species that may enter the alkaline leaching solution during the alkaline leaching pretreatment can be estimated. Then, the amount added can be determined based on the unit adsorption capacity of the tellurium-containing species adsorbent particles for dissolved tellurium-containing species, so that the total adsorption capacity of the adsorbent particles is greater than the amount of dissolved tellurium-containing species released during the alkaline leaching pretreatment. The unit adsorption capacity can be obtained through preliminary static adsorption tests or slurry adsorption tests.

[0032] During the alkaline leaching pretreatment process, the concentration of dissolved tellurium in the alkaline leaching solution can be sampled and detected periodically. The dissolved tellurium concentration can be obtained through inductively coupled plasma (ICP) detection, atomic absorption spectrometry (AAS), or other methods capable of detecting tellurium content in the liquid phase. When the change in dissolved tellurium concentration between two consecutive measurements is less than a preset change, it indicates that the tendency for tellurium-containing components to continue entering the liquid phase from the material surface has weakened, and the alkaline leaching pretreatment can be terminated. The preset change can be pre-set based on detection accuracy, slurry volume, and process control requirements, as long as it is sufficient to determine that the tellurium concentration in the alkaline leaching solution is approaching stability.

[0033] The alkali leaching state can also be determined by observing the change in dissolved tellurium concentration before and after adding tellurium-containing adsorbent particles. Specifically, after adding tellurium-containing adsorbent particles, if the dissolved tellurium concentration in the alkali leaching solution first decreases and then remains stable after stirring for a period of time, it indicates that the dissolved tellurium-containing species in the liquid phase have been fully adsorbed by the adsorbent particles, and the degree of further dissolution of the tellurium-containing coating layer has stabilized. At this point, the alkali leaching pretreatment can be terminated. This method avoids insufficient or excessive pretreatment caused by simply relying on a fixed alkali leaching time.

[0034] After alkaline leaching pretreatment, tellurium-containing adsorbed particles should be separated from the pretreated slurry before cyanide leaching. This separation step is necessary because if tellurium-containing particles enter the cyanide leaching system, they may occupy space and interfere with the migration of gold-cyanide complexes; some adsorbents may also adsorb gold-cyanide complexes. Therefore, separating the tellurium-containing adsorbed particles before cyanide leaching helps maintain the stability of the subsequent cyanide leaching process.

[0035] After separating tellurium-containing adsorbed particles from the pretreated slurry, the pretreated slurry, after removing the adsorbed particles, undergoes solid-liquid separation and washing. Solid-liquid separation removes the alkaline leaching solution, while washing reduces the residual content of dissolved tellurium-containing species, sodium hydroxide residue, and sodium sulfide residue in the pretreated solid material. Washing can be done with water or a dilute alkaline solution; the number of washes depends on the dissolved tellurium concentration in the washing solution. When the dissolved tellurium concentration in the washing solution is lower than a preset tellurium concentration, the pretreated solid material is considered to meet the conditions for cyanide leaching.

[0036] Before proceeding with cyanide leaching, the tellurium content on the surface of the pretreated solid material can be detected. This surface tellurium content can be obtained through scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS), surface washing solution analysis, or other methods that reflect the degree of tellurium residue on the solid surface. When the tellurium content on the surface of the pretreated solid material is lower than a preset tellurium content, it indicates that the tellurium-containing coating has been weakened, making it easier for gold exposure sites to contact sodium cyanide, thus allowing the cyanide leaching step to proceed.

[0037] In the cyanide leaching step, the pretreated solid material is mixed with water to obtain a cyanide slurry. The cyanide slurry is adjusted to alkaline cyanidation conditions, and then sodium cyanide is added while air or oxygen is introduced. This causes the gold in the pretreated solid material to form a gold-cyanide complex with the sodium cyanide and enter the liquid phase, resulting in a gold-containing leachate. Since the alkaline leaching pretreatment stage has already reduced the concentration of tellurium-containing species in the liquid phase through adsorption particles and promoted the continued dissolution of the tellurium capping layer, the subsequent sodium cyanide is mainly used for the complexation leaching of gold, thereby reducing the consumption of sodium cyanide in destroying the tellurium capping layer.

[0038] The separated tellurium-containing adsorbent particles can be regenerated after washing. Regeneration can be achieved by eluting the adsorbent particles with an alkaline solution, salt solution, or alkaline salt solution, allowing the tellurium-containing species adsorbed on the particles to enter the eluent, resulting in a tellurium-containing eluent and regenerated tellurium-containing adsorbent particles. The regenerated tellurium-containing adsorbent particles can be reused for the alkaline leaching pretreatment of the next batch of tellurium-containing gold materials, and the tellurium-containing eluent can be used as a tellurium-containing byproduct for subsequent centralized processing.

[0039] Through the above implementation method, the alkaline leaching pretreatment stage forms a continuous process: tellurium-containing components enter the alkaline leaching solution—adsorbed particles remove dissolved tellurium-containing species—the tellurium-containing coating layer continues to dissolve, thus weakening the tellurium-containing coating layer on the surface of the tellurium-containing gold material before cyanidation. After this pretreatment, the number of gold exposure sites on the surface of the pretreated solid material increases, allowing sodium cyanide to participate more directly in the complexation leaching of gold, thereby achieving the goal of reducing sodium cyanide consumption and improving the stability of the gold-containing leaching solution.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0041] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gold extraction process using enhanced alkaline leaching pretreatment to reduce sodium cyanide consumption, characterized in that: Includes the following steps: The tellurium-containing material is mixed with water to obtain the slurry to be processed; Sodium hydroxide is added to the slurry to be treated to adjust the pH of the slurry and make it alkaline. Sodium sulfide is added to the slurry to be treated under alkaline conditions for alkaline leaching pretreatment, so that at least part of the tellurium-containing components on the surface of the tellurium-containing gold material are converted into dissolved tellurium-containing species and enter the alkaline leaching solution. During the alkaline leaching pretreatment process, tellurium-containing species adsorption particles are added, and the slurry to be treated is continuously stirred so that the tellurium-containing species adsorption particles come into contact with the alkaline leaching solution to adsorb dissolved tellurium-containing species in the alkaline leaching solution. By adsorbing the dissolved tellurium species by the tellurium species adsorption particles, the concentration of dissolved tellurium species in the alkaline leaching solution is reduced, allowing the tellurium-containing coating layer on the surface of the tellurium-containing gold material to continue dissolving into the alkaline leaching solution, thus obtaining a pretreated slurry. The tellurium-containing species adsorbed particles are separated from the pretreated slurry to obtain a pretreated slurry after the tellurium-containing species adsorbed particles have been removed. The pretreated slurry after removing the adsorbed particles containing tellurium species is subjected to solid-liquid separation and washing to obtain the pretreated solid material. Sodium cyanide was added to the pretreated solid material to perform cyanide leaching, resulting in a gold-containing leachate. The dissolved tellurium species are tellurium-containing anions or tellurium-containing oxygen anions that enter the alkaline leaching solution during the alkaline leaching pretreatment of the tellurium-containing gold material; the tellurium-containing species adsorbent particles are particulate materials that maintain a solid particle morphology under alkaline conditions and are capable of adsorbing the dissolved tellurium species.

2. The enhanced alkaline leaching pretreatment gold extraction process for reducing sodium cyanide consumption according to claim 1, characterized in that: The tellurium-containing gold material is tellurium-containing gold concentrate, tellurium-containing gold tailings, or tellurium-containing gold sulfide material, wherein the tellurium-containing gold material contains at least one of gold telluride, silver-gold telluride, and lead telluride associated phases; the tellurium-containing capping layer is a tellurium-containing hydration layer, a tellurium-containing oxide layer, or a tellurium-containing sulfide conversion layer formed on the surface of the tellurium-containing gold material particles, wherein the tellurium-containing capping layer covers the outside of the gold exposure site and prevents subsequent contact between sodium cyanide and gold.

3. The enhanced alkaline leaching pretreatment gold extraction process for reducing sodium cyanide consumption according to claim 2, characterized in that: The tellurium-containing species adsorbent particles include at least one of magnesium-aluminum layered hydroxide particles, magnesium-aluminum composite oxide particles, iron oxide particles, and iron hydroxide particles; or, the tellurium-containing species adsorbent particles include a particle matrix and a tellurium-containing species adsorbent layer disposed on the surface of the particle matrix, wherein the particle matrix is ​​used to maintain the tellurium-containing species adsorbent particles in a separable particle morphology, and the tellurium-containing species adsorbent layer is used to contact and adsorb the dissolved tellurium-containing species.

4. The enhanced alkaline leaching pretreatment gold extraction process for reducing sodium cyanide consumption according to claim 3, characterized in that: The particle matrix is ​​a magnetic particle matrix, and the tellurium-containing species adsorbed particles are separated from the pretreated slurry by magnetic separation; or, the particle matrix is ​​a large-particle-size inert particle matrix, and the particle size of the tellurium-containing species adsorbed particles is larger than the average particle size of the mineral particles formed after grinding the tellurium-containing gold material, and the tellurium-containing species adsorbed particles are separated from the pretreated slurry by screening or sedimentation classification.

5. The enhanced alkaline leaching pretreatment gold extraction process for reducing sodium cyanide consumption according to claim 4, characterized in that: During the alkaline leaching pretreatment, the pH of the slurry to be treated is maintained above pH 12, so that the tellurium-containing components are converted into dissolved tellurium-containing species under alkaline conditions. Furthermore, sodium hydroxide is added first and stirred to bring the slurry to be treated to alkaline conditions before adding sodium sulfide, in order to reduce the ineffective decomposition of sodium sulfide under non-alkaline conditions.

6. The enhanced alkaline leaching pretreatment gold extraction process for reducing sodium cyanide consumption according to claim 5, characterized in that: Before being added to the slurry to be treated, the tellurium-containing adsorbent particles undergo alkali pre-wetting and washing treatment. The alkali pre-wetting treatment is used to remove air from the pores of the tellurium-containing adsorbent particles and to ensure that the tellurium-containing adsorbent particles can fully contact the alkali leaching solution after entering the slurry to be treated. The washing treatment is used to remove soluble impurities from the surface of the tellurium-containing adsorbent particles to reduce the amount of soluble impurities entering the subsequent cyanide leaching stage.

7. The enhanced alkaline leaching pretreatment gold extraction process for reducing sodium cyanide consumption according to claim 6, characterized in that: The tellurium-containing species adsorbent particles are added to the slurry to be treated after the sodium sulfide is added, so that the tellurium-containing components on the surface of the tellurium-containing gold material are first converted into dissolved tellurium-containing species, and then the dissolved tellurium-containing species are adsorbed by the tellurium-containing species adsorbent particles; or, the tellurium-containing species adsorbent particles are added to the slurry to be treated in batches, with the next batch of tellurium-containing species adsorbent particles added after the previous batch of tellurium-containing species adsorbent particles adsorbed the dissolved tellurium-containing species, so as to maintain the adsorption capacity of the alkaline leaching solution for the dissolved tellurium-containing species.

8. The enhanced alkaline leaching pretreatment gold extraction process for reducing sodium cyanide consumption according to claim 7, characterized in that: During the alkaline leaching pretreatment, the concentration of dissolved tellurium in the alkaline leaching solution is detected, and the completion of the alkaline leaching pretreatment is determined based on the dissolved tellurium concentration. The alkaline leaching pretreatment ends when the change in dissolved tellurium concentration between two consecutive detections is less than a preset change; or, the alkaline leaching pretreatment ends when the dissolved tellurium concentration in the alkaline leaching solution decreases after the addition of the tellurium-containing adsorbent particles and remains stable after continued stirring. Before cyanide leaching of the pretreated solid material, the tellurium content on the surface of the pretreated solid material or the dissolved tellurium concentration in the corresponding washing solution is detected. The cyanide leaching step proceeds when the tellurium content on the surface of the pretreated solid material is lower than a preset tellurium content, or the dissolved tellurium concentration in the washing solution is lower than a preset washing solution tellurium concentration. After the alkaline leaching pretreatment, the tellurium-containing coating thickness on the surface of the pretreated solid material is less than the tellurium-containing coating thickness on the surface of the tellurium-containing gold material before the alkaline leaching pretreatment.

9. The enhanced alkaline leaching pretreatment gold extraction process for reducing sodium cyanide consumption according to claim 8, characterized in that: The step of separating the tellurium-containing species adsorbent particles from the pretreated slurry is completed before the cyanide leaching to prevent the tellurium-containing species adsorbent particles from entering the cyanide leaching system and adsorbing gold-cyanide complexes; the washing includes washing the pretreated solid material with clean water or dilute alkali solution at least once to reduce the content of residual dissolved tellurium-containing species in the pretreated solid material; the amount of tellurium-containing species adsorbent particles added is determined according to the tellurium content in the tellurium-containing gold material, so that the adsorption capacity of the tellurium-containing species adsorbent particles for the dissolved tellurium-containing species is greater than the amount of dissolved tellurium-containing species released by the tellurium-containing gold material during the alkali leaching pretreatment.

10. The enhanced alkaline leaching pretreatment gold extraction process for reducing sodium cyanide consumption according to claim 9, characterized in that: The cyanide leaching process includes the following steps: mixing the pretreated solid material with water to obtain a cyanide slurry; adjusting the pH of the cyanide slurry to place it under alkaline cyanidation conditions; adding sodium cyanide to the cyanide slurry and introducing air or oxygen to allow gold in the pretreated solid material to enter the liquid phase, resulting in the gold-containing leaching solution; the cyanide leaching is performed after the tellurium-containing capping layer has been weakened by the alkaline leaching pretreatment, allowing the sodium cyanide to contact the exposed gold surface in the pretreated solid material and form a gold-cyanide complex; the separated tellurium-containing species adsorbed particles are washed and then regenerated, the regeneration process removing the tellurium-containing species adsorbed on the particles and allowing them to be reused for the alkaline leaching pretreatment of the next batch of tellurium-containing gold material; the regeneration process includes eluting the tellurium-containing species adsorbed particles with an alkaline solution, a salt solution, or an alkaline salt solution to obtain a tellurium-containing eluent and regenerated tellurium-containing species adsorbed particles.

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