Method for cyaniding, smelting and extracting oxidized gold ore carbon slurry

Abstract

The invention relates to a gold oxide ore carbon slurry cyaniding smelting extraction method which comprises the following steps: 1) pretreating ore pulp: adding lime milk into gold oxide ore powder, adjusting the pH value to be greater than 10.5 to obtain ore pulp, then adding a pretreating agent, and fully and uniformly mixing to obtain pretreated ore pulp; (2) synchronous cyaniding leaching and adsorption are conducted, specifically, the pretreated ore pulp is subjected to synchronous leaching and adsorption, in the process, the concentration of free cyanogen is controlled to be 0.04%-0.06%, the PH value is controlled to be larger than 10.5, the concentration of a carbon adsorbent is controlled to be 18-22 g / L, and a gold loading material is obtained; the gold loading material is desorbed till the gold concentration in a desorption solution is smaller than or equal to 0.2 mg / L, desorption is stopped, a pregnant solution is obtained and then electrolyzed, when the gold concentration is smaller than or equal to 0.2 mg / L, electrolysis is stopped, scraping is conducted, and gold mud is obtained, and (4) smelting and aftertreatment are conducted, the gold mud is smelted and subjected to aftertreatment, and gold is obtained.The process has the advantages of being small in cyanide consumption and the like.

Description

Technical Field

[0001] This application relates to the field of mineral smelting and extraction, and in particular to a method for smelting and extracting oxidized gold ore by carbon slurry cyanidation. Background Technology

[0002] As a vital strategic resource and precious metal, gold's efficient extraction technology has always been a core research focus in the mineral processing field. With the long-term development of global gold resources, the reserves of easily processed high-grade gold oxide ores have been continuously decreasing, leading to a trend of "lower grade, greater complexity, and greater difficulty in processing" in mineral resources. Currently, the industry's main processing targets have shifted to complex gold oxide ores that are low-grade, high in clay, carbonaceous, or contain polymetallic compounds. The smelting and extraction of these ores are significantly more difficult than before, placing higher demands on existing technologies. Carbon-in-pulp cyanidation (CIP) has developed against this backdrop and plays a crucial role in the smelting of gold oxide ores. It has provided support for technological advancements in the gold extraction industry and promoted the sustainable development of the gold smelting sector.

[0003] In the smelting and extraction of oxidized gold ores, carbon-in-pulp cyanidation (CIP) is currently the mainstream process for processing oxidized gold ores. This process combines cyanide leaching with activated carbon adsorption to achieve the separation and enrichment of gold. Its core principle is that in an alkaline medium environment, cyanide is used as the leaching agent to react with gold in the ore to form a soluble gold-cyanide complex. Then, activated carbon selectively adsorbs the gold-cyanide complex in the slurry, thus completing the gold extraction. Due to its compact process, convenient operation, and strong adaptability to oxidized gold ores, this process occupies an important position in the gold extraction industry, providing a certain amount of gold resources to the market and meeting some of the market's demand for gold.

[0004] However, existing carbon-in-pulp cyanidation (CIP) processes face significant technical bottlenecks when dealing with increasingly complex gold oxide ores. In practical industrial applications, this process is highly susceptible to the significant impact of impurities in the ore, particularly soluble metal ions such as copper, iron, and zinc. These impurity metal ions preferentially undergo non-targeted complexation or oxidation reactions with cyanides, consuming large amounts of available cyanide ions in the pulverized pulp. This reduces the effective reagent concentration for gold complexation, thus hindering the gold dissolution kinetics. Simultaneously, some impurity complexes compete with gold-cyanide complexes for adsorption sites on activated carbon, reducing the adsorption selectivity and capacity of activated carbon for gold. Ultimately, this results in a low gold concentration in the leaching pulp, making it difficult to improve the overall gold recovery rate.

[0005] This problem is particularly prominent in certain types of oxidized gold ores, such as those rich in copper, iron, and other easily cyanide-complexing metal minerals; oxidized gold ores with excessively high carbonate content that makes it difficult to control the alkalinity of the system; and strongly muddy / clayized oxidized gold ores with high ore mudification and high slurry viscosity. Not only is the cyanide consumption per unit high, but the dissolution and adsorption processes are also hindered, resulting in a significant decrease in gold extraction efficiency and economics. Summary of the Invention

[0006] To reduce problems such as high cyanide consumption and hindered dissolution and adsorption during the extraction process, and to improve gold extraction efficiency, a carbon-in-pulp cyanidation extraction method for oxidized gold ore is provided.

[0007] This application provides a method for extracting oxidized gold ore by carbon-in-pulp cyanidation smelting, wherein the ore is prepared by the following method: 1) Pre-treated slurry: Lime milk is added to gold oxide ore powder to adjust the pH to greater than 10.5 to obtain a slurry. Then, a pre-treatment agent is added and mixed thoroughly to obtain a pre-treated slurry. The effective components of the pre-treatment agent are activated sepiolite fiber, active modified nanocellulose, and hydrogen-terminated hyperbranched polyamide in a weight ratio of 1:(1.8-3.2):(1.2-2.5):(0.8-1.5). 2) Simultaneous cyanide leaching and adsorption: The pretreated slurry is subjected to simultaneous leaching and adsorption. During this process, the free cyanide concentration is controlled at 0.04%-0.06%, the pH value is greater than 10.5, and the carbon adsorbent concentration is 18-22 g / L to obtain gold-loaded material. 3) Desorption and electrolysis: Desorption of the gold-loaded material is carried out until the gold concentration in the desorption solution is ≤0.2mg / L, then desorption is stopped to obtain a precious solution. Electrolysis is then carried out until the gold concentration is ≤0.2mg / L, then electrolysis is stopped and the gold mud is scraped off. 5) Smelting and post-processing: The gold mud is smelted and post-processed to obtain gold.

[0008] This method establishes a stable extraction process through raw material synergy and process enhancement, achieving reduced cyanide consumption and increased gold extraction rate, as detailed below: A synergistic system is formed by activating sepiolite fibers, modifying nanocellulose, and terminal hydrogen-based hyperbranched polyamide in a specific weight ratio. Activated sepiolite fibers capture free metal ions through physical adsorption and reduce slurry viscosity; modified nanocellulose targets and complexes impurity ions; and terminal hydrogen-based hyperbranched polyamide enhances the synergistic effect of the two, regulates the slurry environment, and slowly releases effective CN⁻. This synergistic effect significantly reduces the ineffective consumption of cyanide caused by impurity ions. Combined with simultaneous cyanide leaching and adsorption in step 2, and controlling the free cyanide concentration at 0.04%-0.06%, reagent utilization is improved. Controlling the pH value to be greater than 10.5 and the carbon adsorbent concentration to 18-22 g / L, this precise control of process parameters and efficient integration with the pretreatment agent synergistically maintains a stable leaching environment and efficient activated carbon adsorption, further improving gold leaching and adsorption rates.

[0009] Step 3 employs a dual control standard of "desorption to a gold concentration ≤ 0.2 mg / L in the desorption solution and electrolysis to a gold concentration ≤ 0.2 mg / L," combined with the specific processes of steps 1) and 2), to achieve deep gold recovery. Finally, combined with the smelting and post-processing processes in step 4), a stable closed-loop system is formed, resulting in lower total cyanide consumption and higher gold purity. Even when further processing is applied to oxidized gold ores rich in easily cyanide-complexing metal minerals such as copper and iron, oxidized gold ores with excessively high carbonate content leading to difficulty in controlling the system's alkalinity, and strongly muddy / clayized oxidized gold ores with high ore mudification and high slurry viscosity, the cyanide content can be further reduced, and higher extraction yield and purity can be obtained.

[0010] In summary, the technological advantages of this application stem from the deep integration of "precise raw material system + adapted process parameters," forming a stable extraction mechanism throughout the entire process from pretreatment to deep recovery. At the raw material level, the pretreatment agent, constructed from activated sepiolite fiber, active modified nanocellulose, and terminal hydrogen-based hyperbranched polyamide in a specific ratio, fixes impurity ions and optimizes the slurry environment from the source through the synergistic effect of "physical adsorption-chemical complexation-system stabilization," laying the foundation for reduced consumption in subsequent processes. At the process level, the precise control of free cyanide concentration, pH value, and carbon adsorbent concentration in step 2 forms an efficient connection with the pretreatment effect, avoiding ineffective consumption of cyanide and ensuring efficient leaching and adsorption of gold. The dual endpoint control of desorption and electrolysis in step 3 achieves deep recovery of gold, reducing gold loss throughout the process. The smelting and post-treatment in step 4) ensure the quality of the final gold.

[0011] This closed-loop system of "coordinated impurity reduction of raw materials - precise efficiency improvement of processes - deep end-stage recovery - impurity removal in smelting" creates positive gains in each link: the impurity control of pretreatment agents reduces the difficulty of process parameter regulation, and the stable process environment improves the efficiency of raw material action.

[0012] Preferably, the active modified nanocellulose is sulfonated modified cellulose nanocrystals and / or EMPO oxidized nanocellulose.

[0013] Preferably, the weight ratio of the sulfonated modified cellulose nanocrystals to the EMPO oxidized cellulose nanocrystals is 1:(0.5-1.5).

[0014] This application further limits the active modified cellulose nanocrystals to sulfonated modified cellulose nanocrystals and / or EMPO oxidized cellulose nanocrystals, which significantly improves the complexation effect of impurity ions. Specifically, sulfonated modified cellulose nanocrystals introduce a large number of highly polar sulfonic acid groups (-SO3H) into their molecular chains through sulfonation. The stability constant of the complexes formed by these sulfonic acid groups and metal ions such as copper, iron, and zinc is increased by 2-3 orders of magnitude compared to ordinary modified cellulose, and their dissociation degree is extremely low in a pretreatment environment of pH 10.5-11.5, enabling long-term fixation of impurity ions.

[0015] EMPO-oxidized nanocellulose constructs high-density carboxyl (-COOH) and aldehyde (-CHO) active sites on the cellulose surface through the oxidation reaction of 2,2,6,6-tetramethylpiperidine-1-oxygen free radical (TEMPO). The chelation reaction rate of its carboxyl groups with metal ions is improved, which can quickly capture metal ions that are instantaneously dissolved in the slurry and avoid their secondary dissociation during the pretreatment stage.

[0016] The two types of modified cellulose can be used alone or in combination. Sulfonated modified cellulose nanocrystals achieve long-term fixation of impurities due to their high stability, while EMPO oxidized cellulose nanocrystals achieve rapid capture of impurities due to their high reactivity. When the two are combined, they form a "fast capture-stable" synergistic complexation system. This precise structural modification makes the complexation selectivity of the active modified cellulose nanocrystals for metal ions such as copper and iron significantly higher than that for gold ions. It can form stable chelates with dissolved metal ions in the slurry during the pretreatment stage, and the chelates will not decompose in the subsequent alkaline cyanidation environment. Thus, impurity ions are chemically fixed efficiently, minimizing their competitive reaction with cyanide.

[0017] Preferably, the effective component content in the pretreatment agent is 20-30 wt%; the ratio of the amount of gold oxide ore powder to the effective component of the pretreatment agent is 1000:(1-5).

[0018] Furthermore, the content of the effective ingredient in the pretreatment agent is limited to 20-30 wt%, and the ratio of oxidized gold ore powder to the effective ingredient in the pretreatment agent is specified as 1000:(1-5). This dual limitation achieves an optimal balance between the efficiency and economy of the pretreatment agent, significantly improving the technical effect. The value of optimizing the effective ingredient content: An effective ingredient content of 20-30 wt% is based on a precise match between "efficiency and cost control." If the effective ingredient content is below 20 wt%, the concentration of core components such as activated sepiolite fiber and specifically modified nanocellulose will be insufficient. When faced with a large number of impurity ions in complex slurries, the adsorption and complexation sites are easily saturated, making it difficult to achieve efficient impurity fixation, which will weaken the subsequent cyanide consumption control effect. If the content is above 30 wt%, on the one hand, it will increase the preparation cost of the pretreatment agent, and the excess effective ingredient is prone to agglomeration in the slurry, which will reduce the exposure efficiency of the active sites. On the other hand, it will cause the slurry viscosity to increase abnormally, affecting the mass transfer effect during subsequent cyanide leaching. The content range of 20-30 wt% can ensure that the effective ingredient is uniformly dispersed in the slurry, so that each active site can efficiently contact impurity ions, while avoiding raw material waste and reducing the economic cost of the pretreatment stage.

[0019] The above raw material dosage range, and the matching effect of the ratio of gold oxide ore powder to effective ingredient dosage, achieves a dynamic match between "impurity loading and processing capacity". This limitation is deeply matched with the pretreatment agent component synergistic system and subsequent process parameters. The effective ingredient content of 20-30wt% can ensure the stability of the physicochemical properties of the slurry after pretreatment, providing favorable conditions for the precise control of the free cyanide concentration (0.04%-0.06%) in step 2 - avoiding frequent adjustments to the cyanide concentration due to fluctuations in impurity residue; while the dosage ratio of 1000:(1-5) increases the gold exposure of the slurry after pretreatment, matching the carbon adsorbent concentration of 18-22 g / L in step 2, allowing activated carbon to preferentially adsorb gold-cyanide complexes, further improving the gold adsorption efficiency.

[0020] Preferably, the mixing conditions in step 1) are: ultrasonic dispersion, total time 20-30 min, and pressure 0.05-1.5 MPa.

[0021] During the pretreatment slurry stage, ultrasonic dispersion for 20-30 minutes at a pressure of 0.05-1.5 MPa ensures thorough and uniform mixing of gold oxide ore powder, lime slurry, and pretreatment agent to form a suspension, which is beneficial for subsequent adsorption processes. Adding lime slurry to the gold oxide ore powder to adjust the pH to greater than 10.5, followed by the addition of a pretreatment agent composed of activated sepiolite fiber, activated modified nanocellulose, and terminal hydrogen-based hyperbranched polyamide in a specific weight ratio, effectively fixes impurity ions and optimizes the slurry environment from the source. Simultaneous cyanide leaching and adsorption processes control the free cyanide concentration at 0.04%-0.06%, the pH value to greater than 10.5, and the carbon adsorbent concentration at 18-22 g / L, improving reagent utilization and maintaining a stable leaching environment and efficient activated carbon adsorption. Desorption and electrolysis employ dual control standards to achieve deep gold recovery. The smelting and post-treatment form a stable closed-loop system, resulting in lower total cyanide consumption, higher gold purity, and improved gold extraction efficiency.

[0022] Preferably, the particle size of the gold oxide ore powder is 200-300 mesh.

[0023] In the carbon-in-pulp cyanidation smelting and extraction of gold oxide ore, the particle size of the gold oxide ore powder is controlled at 200-300 mesh. This avoids the problems of gold oxide ore powder with too large a particle size easily settling, and too small a particle size being unfavorable for subsequent dispersion and easy agglomeration during ultrasonic treatment.

[0024] Preferably, the specific process in step 2) is as follows: the pretreated slurry is pumped into a 6-8 stage series leaching and adsorption system. Starting from the second stage leaching tank, sodium cyanide solution is added to control the free cyanide concentration of the entire system at 0.04%-0.06%, the pH value at more than 10.5, the carbon adsorbent concentration at 18-22 g / L, and the total leaching time of the slurry at 20-30 h to obtain gold-loaded material.

[0025] In the carbon-in-pulp smelting extraction method for oxidized gold ore, after adding lime slurry and pretreatment agent, the pretreated slurry is pumped into a 6-8 stage series leaching and adsorption system. Sodium cyanide solution is added starting from the second stage leaching tank. The concentration of free cyanide, pH value, and carbon adsorbent concentration are controlled so that within a total leaching time of 20-30 hours, the elemental gold in the gold ore dissolves under the action of cyanide and oxygen to generate gold-cyanide complex anions, which are immediately captured by the counter-moving composite carbon adsorbent. This maximizes the mass transfer driving force, reduces excessive cyanide consumption, ensures improved leaching and adsorption efficiency, stabilizes the extraction process, and achieves reduced cyanide consumption and increased gold extraction rate.

[0026] Preferably, the carbon adsorbent is one or more of activated carbon, ion exchange resin, mesoporous silica, and diatomaceous earth, and contains at least activated carbon.

[0027] The carbon adsorbent employs a combination of one or more of activated carbon, ion exchange resin, mesoporous silica, and diatomaceous earth, with at least activated carbon included. This approach leverages the strengths of each material: activated carbon possesses a rich pore structure and a large specific surface area, enabling effective adsorption of gold-cyanide complexes; ion exchange resin selectively adsorbs gold ions through ion exchange; mesoporous silica has a regular mesoporous structure, providing more adsorption sites; and diatomaceous earth exhibits excellent adsorption and filtration properties. The synergistic effect of these materials significantly improves the adsorption efficiency and selectivity for gold-cyanide complexes, effectively reducing gold loss and increasing gold recovery. Furthermore, by combining specific pretreatment agents in the pretreatment slurry to reduce the ineffective consumption of cyanide by impurity ions, precise control of process parameters during simultaneous cyanide leaching and adsorption, dual control standards during desorption and electrolysis, and processes such as smelting and post-treatment, the system collectively achieves reduced cyanide consumption and increased gold extraction rate, forming a stable closed-loop system for gold extraction.

[0028] Preferably, the activated sepiolite fiber is acidified sepiolite fiber. The specific steps for acidifying sepiolite fiber are as follows: after drying, the sepiolite fiber is added to a dilute hydrochloric acid solution and stirred at 60°C for 1 hour to remove carbonate and metal oxide impurities from the fiber surface.

[0029] In the process of carbon-slurry cyanidation smelting and extraction of oxidized gold ore, acidification treatment of sepiolite fiber can remove carbonate and metal oxide impurities from the fiber surface, improve the performance of pretreatment agents, and thus facilitate the physical adsorption and capture of free metal ions, reduce slurry viscosity, reduce the interference of slurry and impurities on gold extraction, and improve the gold recovery rate.

[0030] Preferably, the pyrometallurgical refining process in step 4) is as follows: the crude gold powder after impurity removal is mixed with flux at a weight ratio of 10:(1-1.5), and the resulting mixture is heated to 1100-1200℃ and smelted for 1-2 hours. The impurities and flux form slag that floats on the surface. After removing the slag, gold ingots are obtained. The solvents include: borax, sodium carbonate, and quartz sand.

[0031] First, the pH of the gold oxide ore powder is adjusted by adding lime milk, and then a pretreatment agent is added to obtain a pretreated slurry. Then, simultaneous cyanide leaching and adsorption are carried out to obtain gold-loaded material. Next, the gold-loaded material is desorbed and electrolyzed to obtain gold mud. Finally, during pyrometallurgical refining, the impurity-removed coarse gold powder is mixed with a flux containing borax, sodium carbonate, and quartz sand at a weight ratio of 10:(1-1.5), and the mixture is heated to 1100-1200℃ and smelted for 1-2 hours. This allows impurities and flux to form slag that floats on the surface. After removing the slag, gold ingots are obtained. This process maximizes the recovery of gold from the solid phase to the liquid phase and back to the solid phase, minimizing process losses. It also facilitates the regeneration of desorbed lean material and the recycling of lean liquor.

[0032] In summary, this application includes at least one of the following beneficial technical effects: 1. A synergistic system is formed by activated sepiolite fiber, active modified nanocellulose, and terminal hydrogen-based hyperbranched polyamide in a specific weight ratio. Activated sepiolite fiber physically adsorbs and captures free metal ions and reduces slurry viscosity. Active modified nanocellulose targets and complexes impurity ions. Terminal hydrogen-based hyperbranched polyamide enhances synergy, regulates the slurry environment, and slowly releases effective CN⁻. Combined with simultaneous cyanide leaching and adsorption, as well as the control of free cyanide concentration, pH value, and carbon adsorbent concentration, the ineffective consumption of cyanide caused by impurity ions is significantly reduced, and the reagent utilization rate is greatly improved. 2. Precisely control process parameters such as free cyanide concentration, pH value, and carbon adsorbent concentration during the simultaneous leaching and adsorption process, and work efficiently with pretreatment agents to create a stable leaching environment, ensuring efficient adsorption of activated carbon and effectively improving the leaching and adsorption rates of gold. 3. Adopting a dual control standard of "desorption to gold concentration ≤0.2mg / L in the desorption solution and electrolysis to gold concentration ≤0.2mg / L", combined with specific processes such as pretreatment and simultaneous leaching and adsorption, deep gold recovery is achieved. Combined with smelting and post-processing processes, the total consumption of cyanide is effectively reduced and the purity of gold is significantly improved. Detailed Implementation

[0033] The present application will be further described in detail below with reference to the embodiments.

[0034] Raw material introduction;

[0035] Sepiolite fiber, density 2.0-2.3g / cm², purity 90%, thickness 4-5mm; Sulfonated modified cellulose nanocrystals are Tianlu Nano TL010-2 EMPO oxidized nanocellulose is Tianlu Nano TL-005; The hydrogen-terminated hyperbranched polyamide is Maidehao MDH25410; Activated carbon, mesoporous silica, and diatomaceous earth were all sieved through a 200-mesh sieve; Mesoporous silica has a pore size of 2-50 nm and a porosity of 68-78%. Oxide gold ore powder: Type A, common gold ore, with the following chemical composition: Gold (Au): 20-30 g / t; Silica: 60%-70%; Alumina: 10%-15%; Calcium carbonate: 3%-10%; Iron oxide: 2%-5%, Copper (Cu): 0.01%-0.5%; Zinc (Zn): 0.01%-0.3%; Lead (Pb): 0.005%-0.2%; other components 1-3%; Type B: Oxide gold ore rich in easily cyanidated complexing metal minerals such as copper and iron, gold (Au) 10-15 g / t; main easily cyanidated complexing impurities (copper, iron), copper (Cu): 3-5%; iron (Fe): 25-30%; zinc (Zn): 0.1%-1%; lead (Pb): 0.05%-0.5%; arsenic (As) content is usually <0.5%; arsenic ore can reach 1%-2%; silicon dioxide: 45%-60%; aluminum oxide 1%-10%; calcium carbonate: 2%-8%, with the balance being other components (approximately 1%). Type C: Target element (gold) 5-8g / t; Montmorillonite: 5%-20%; Kaolinite: 3%-15%; Chlorite: 2%-8%; Iron (Fe): 8%-15%; Copper (Cu): 0.1%-1%; Zinc (Zn) / Lead (Pb): content is 0.05%-0.5% and 0.02%-0.3% respectively; Silicon dioxide: 30%-55%; Aluminum oxide: 8%-20%; Calcium carbonate (CaCO3): 2%-5%; Magnesium, potassium, and sodium oxides: 1%-6% in total; the balance is other chemical components (approximately 1%). Example

[0036] Example 1 A method for extracting oxidized gold ore by carbon-in-pulp cyanidation smelting, comprising the following steps: Type A, Type B, and Type C gold oxide powders were extracted using the following preparation methods. 1) Pre-treated slurry: Weigh 200-mesh gold oxide ore powder (Type A / Type B / Type C), add 15% lime milk (by mass), adjust the pH to 11, stir at 100 r / min for 10 min to obtain the slurry, then add the pre-treatment agent and mix thoroughly with the slurry. Disperse using ultrasound for a total time of 30 min at a pressure of 1 MPa and a frequency of 60 kHz to obtain the pre-treated slurry. Pre-treatment agent: The effective components of the pre-treatment agent consist of activated sepiolite fiber, active modified nanocellulose, and terminal hydrogen-based hyperbranched polyamide in a weight ratio of 1:2.5:2:1.5; the content of the effective components in the pre-treatment agent is 25 wt%; the active modified nanocellulose is sulfonated modified cellulose nanocrystals.

[0037] 2) Simultaneous cyanide leaching and adsorption: The pretreated slurry is pumped into a 6-stage series leaching and adsorption system. Starting from the second stage leaching tank, sodium cyanide solution is added. The free cyanide concentration of the entire system is controlled at 0.05%, the pH value is 11, the carbon adsorbent concentration is maintained at 20 g / L, and the total leaching time of the slurry is 22 h to obtain gold-loaded material. 3) Desorption and electrolysis: The gold-loaded material is placed in the desorption tank for desorption. The gold concentration in the desorption solution is monitored by detection equipment during the desorption process. Desorption agent preparation: The desorption solution was prepared by mixing NaOH and NaCN in a weight ratio of 1:1, wherein the concentration of NaOH was 1.0 wt% and the concentration of NaCN was 0.1 wt%, and the temperature of the desorption solution was heated to 90℃; Desorption equipment: A vertical desorption column (diameter φ1.2m, height 8m) is used, and gold-loaded carbon is loaded into the desorption column (the loading amount is 80% of the column volume). Process parameters: Desorption solution flow rate 2 BV / h (BV is the desorption column volume), desorption pressure 0.15 MPa, total desorption time 12 h, desorption solution is recycled (temperature is maintained by a heater) until the gold concentration in the desorption solution is ≤0.5 mg / L, at which point desorption is stopped (the gold-loaded carbon becomes lean carbon after desorption and is returned to the pretreatment for recycling). The resulting precious solution is then placed in an electrolytic cell containing electrolyte for electrolysis, and the gold concentration is monitored by a detection device. The desorbed precious liquor is filtered through a plate filter press (filter cloth pore size 0.1μm) to remove suspended impurities and then pumped into an electrolytic cell. The electrolysis equipment consists of a stainless steel cathode (plate-shaped, 1000×500×5mm) and a lead-silver alloy anode (Ag content 2%, 1000×500×10mm), with a 100mm electrode spacing. Process parameters include: electrolysis voltage 3V, current density 200A / m², electrolysis temperature 40℃, and electrolysis time 18h. Electrolysis is immediately stopped when the gold concentration in the precious liquor is ≤0.2mg / L. Gold sludge is scraped from the cathode surface, and the lean liquor is returned to the desorbate preparation process for recycling. The obtained gold sludge is used in subsequent processes. The gold mentioned above refers to gold ions.

[0038] 4) Smelting and post-processing: The gold mud is mixed evenly with a solvent (composed of borax, sodium carbonate, and quartz sand in a weight ratio of 1:1:2), and then placed in an oven at 100°C for 10 minutes to remove moisture, resulting in a mixture. The mixture is then placed in a graphite crucible and placed in a medium-frequency induction furnace, heated to 1100~1200°C, and smelted for 1~2 hours. Impurities and flux form slag that floats to the surface. After removing the slag, gold is obtained. The tailings generated during the process are recycled to obtain gold.

[0039] The active modified nanocellulose is a sulfonated modified cellulose nanocrystal.

[0040] The effective component ratio of oxidized gold ore powder to pretreatment agent is 1000:3.3.

[0041] The carbon adsorbent is composed of activated carbon, mesoporous silica, and diatomaceous earth in a weight ratio of 8:1:0.8:0.2.

[0042] Activated sepiolite fiber is acidified sepiolite fiber. The specific steps for acidifying sepiolite fiber are as follows: After drying, the sepiolite fiber is added to a 20% dilute hydrochloric acid solution and stirred at 60°C for 1 hour to remove carbonate and metal oxide impurities from the fiber surface.

[0043] Example 2 The difference between Example 2 and Example 1 lies in the amount of the ingredients used and some process parameters, as detailed below: In step 1), the effective components of the pretreatment agent consist of activated sepiolite fiber, activated modified nanocellulose, and terminal hydrogen-based hyperbranched polyamide in a weight ratio of 1:1.8:1.2:1; the total time is 30 min and the pressure is 0.05 MPa.

[0044] In step 2), the cyanide concentration is 0.04%, the pH value is 11, the carbon adsorbent concentration is maintained at 18 g / L, and the total leaching time of the slurry is 30 h.

[0045] The effective ingredient content in the pretreatment agent is 20wt%; the ratio of the amount of gold oxide ore powder to the effective ingredient in the pretreatment agent is 1000:5.

[0046] In step 4), the coarse gold powder and flux are mixed evenly at a weight ratio of 10:1. The resulting mixture is then heated to 1200℃ and smelted for 1 hour.

[0047] Example 3 The difference between Example 3 and Example 1 lies in the amount of the ingredients used and some process parameters, as detailed below: In step 1), the effective components of the pretreatment agent consist of activated sepiolite fiber, activated modified nanocellulose, and terminal hydrogen-based hyperbranched polyamide in a weight ratio of 1:3.2:2.5:0.8; the total time is 20 min and the pressure is 0.15 MPa.

[0048] In step 2), the cyanide concentration is 0.06%, the pH value is 11, the carbon adsorbent concentration is maintained at 22 g / L, and the total leaching time of the slurry is 20 h.

[0049] The effective ingredient content in the pretreatment agent is 30 wt%; the ratio of the amount of gold oxide ore powder to the effective ingredient in the pretreatment agent is 1000:1.

[0050] In step 4), the coarse gold powder and flux are mixed evenly at a weight ratio of 10:1. The resulting mixture is then heated to 1200℃ and smelted for 1 hour.

[0051] Example 4 The difference between Example 4 and Example 1 is that the active modified nanocellulose is EMPO oxidized nanocellulose.

[0052] Example 5 The difference between Example 5 and Example 1 is that the active modified nanocellulose is composed of sulfonated modified cellulose nanocrystals and EMPO oxidized nanocellulose in a weight ratio of 1:0.5.

[0053] Example 6 Example 6 differs from Example 1 in that the active modified nanocellulose is composed of sulfonated modified cellulose nanocrystals and EMPO oxidized nanocellulose in a 1:1 weight ratio. Example 7 The difference between Example 7 and Example 1 is that the active modified nanocellulose is composed of sulfonated modified cellulose nanocrystals and EMPO oxidized nanocellulose in a weight ratio of 1:1.5.

[0054] Comparative Example

[0055] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that no pretreatment agent was added in step 1). The specific process of step 1) is as follows: 1) Pre-treated slurry: Weigh 200-mesh gold oxide ore powder and add 15% lime milk by mass. Adjust the pH to 11, stir at 100 r / min for 10 min to obtain the slurry. Then disperse it using ultrasound for a total time of 30 min at a pressure of 1 MPa and a frequency of 60 kHz to obtain the pre-treated slurry.

[0056] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the effective component of the pretreatment agent is a terminal hydrogen-based hyperbranched polyamide.

[0057] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the effective component of the pretreatment agent is active modified nanocellulose.

[0058] Performance testing Test 1; Referring to the method for determining cyanide reagent consumption in the "Test Procedure for Ore Dressing" (YS / T3001-2016), the total consumption was calculated by the difference between "addition amount and residual amount". The residual total cyanide was detected by the distillation-titration method of total cyanide in GB7486-1987. When the cyanide consumption in types A, B, and C is less than 0.5 kg / t, it is considered that the cyanide consumption is qualified. Using Comparative Example 1 as the control group, the cyanide reduction rate of types A, B, and C in Examples 1-7 and Comparative Examples 1-3 was calculated respectively. The cyanide reduction rate is equal to the consumption of the control group minus the consumption of types A / B / C, then divided by the consumption of the control group, and finally 100%.

[0059] The cyanide reduction rate levels are as follows: Level A is greater than 45%; 35% < Level B ≤ 45%; 20% < Level C ≤ 35%; 10% < Level D ≤ 20%; Level E ≤ 10%.

[0060] Test Two: Gold extraction rate: "Methods for chemical analysis of gold ores - Part 1: Determination of gold content" (GB / T 20899.1 - 2019): Fire assay method; "Calculation methods for process technical indicators of ore dressing plants" (ZBY 001 - 1987), the formula is: Gold recovery rate (%) = (finished gold amount + recoverable amount of residual gold in tail liquid / slag) / total gold amount in raw ore × 100%. When the recovery rates of Type A / Type B / Type C gold ores are all greater than 95%, it is recorded as qualified extraction rate.

[0061] Gold purity: Tested according to "Gold ingots" (GB / T 4134 - 2015). When the gold purities obtained from Type A, Type B, and Type C are all greater than 99%, it is recorded as qualified.

[0062] Examples 1 - 7 and Comparative Examples 1 - 3 obtained the gold ingot content and Table 1 Experimental data of Examples 1 - 7 and Comparative Examples 1 - 3

[0063] Combining Example 1 and Comparative Examples 1 - 3 with Table 1, it can be seen that in Comparative Example 1, the extraction rate, gold purity, and cyanide consumption all show unqualified phenomena. In Comparative Example 2, the cyanide consumption shows an unqualified phenomenon. In Comparative Example 3, both the extraction rate and cyanide consumption show unqualified phenomena. And for Comparative Examples 2 - 3, the cyanide reduction rate level of Type A reaches Level B (35% < Level B ≤ 45%) and Level C (20% < Level C ≤ 35%). For Type B and Type C, in Comparative Example 2, it all reaches Level D (10% < Level D ≤ 20%), and in Comparative Example 3, it reaches Level E (Level E ≤ 10%). While in Example 1, the extraction rate (recovery rate is greater than 95%), gold purity (gold purity is greater than 99%), and cyanide consumption (cyanide consumption in Type A, Type B, and Type C is all less than 0.5 kg / t) all show qualified phenomena, indicating that using the production process of this application in combination with the active ingredients of the pretreatment agent composed of activated sepiolite fiber, active modified nanocellulose, and terminal hydrogen - based hyperbranched polyamide in a weight ratio of 1:2.5:2:1.5 can play a better synergistic effect, further reducing the ineffective consumption of cyanide. At the same time, even for oxidized gold ores rich in easily cyanide - complexing metals such as copper and iron, or oxidized gold ores with too high carbonate content resulting in difficult regulation of system alkalinity, it can also greatly reduce the cyanide content and obtain a higher extraction amount and extraction purity.

[0064] Compared with Example 1, for oxidized gold ores of types B and C that are relatively difficult to extract, when using activated modified nanocellulose composed of sulfonated modified cellulose nanocrystals and EMPO oxidized nanocellulose, and compounding the two of them, a synergistic effect can be achieved, thereby effectively increasing the cyanide reduction rate level of types B and C from grade B (35% < grade B ≤ 45%) to grade A (greater than 45%).

[0065] This specific embodiment is only an interpretation of the present application, and it is not a limitation to the present application. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A method for extracting oxidized gold ore by carbon-in-pulp cyanidation, characterized in that, It is prepared by the following method: Pretreated slurry: Lime milk is added to gold oxide ore powder to adjust the pH to greater than 10.5 to obtain a slurry. Then, a pretreatment agent is added and mixed thoroughly to obtain a pretreated slurry. The effective components of the pretreatment agent are activated sepiolite fiber, active modified nanocellulose, and terminal hydrogen-based hyperbranched polyamide in a weight ratio of 1:(1.8-3.2):(1.2-2.5):(0.8-1.5). 2) Simultaneous cyanide leaching and adsorption: The pretreated slurry is subjected to simultaneous leaching and adsorption. During this process, the free cyanide concentration is controlled at 0.04%-0.06%, the pH value is greater than 10.5, and the carbon adsorbent concentration is 18-22 g / L to obtain gold-loaded material. 3) Desorption and electrolysis: Desorption of the gold-loaded material is carried out until the gold concentration in the desorption solution is ≤0.2mg / L, then desorption is stopped to obtain a precious solution. Electrolysis is then carried out until the gold concentration is ≤0.2mg / L, then electrolysis is stopped and the gold mud is scraped off. 4) Smelting and post-processing: The gold mud is smelted and post-processed to obtain gold.

2. The method for extracting oxidized gold ore by carbon-in-pulp cyanidation according to claim 1, characterized in that: The active modified nanocellulose is sulfonated modified cellulose nanocrystals and / or EMPO oxidized nanocellulose.

3. The method for extracting oxidized gold ore by carbon-in-pulp cyanidation according to claim 2, characterized in that: The weight ratio of the sulfonated modified cellulose nanocrystals to the EMPO oxidized nanocellulose is 1:(0.5-1.5).

4. The method for extracting oxidized gold ore by carbon-in-pulp cyanidation according to claim 1, characterized in that: The effective ingredient content in the pretreatment agent is 20-30 wt%; the ratio of the effective ingredient in the gold oxide ore powder to the effective ingredient in the pretreatment agent is 1000:(1-5).

5. The method for extracting oxidized gold ore by carbon-in-pulp cyanidation according to claim 1, characterized in that, The mixing conditions in step 1) are as follows: ultrasonic dispersion is used, with a total time of 20-30 minutes and a pressure of 0.05-1.5 MPa.

6. The method for extracting oxidized gold ore by carbon-in-pulp cyanidation according to claim 1, characterized in that: The particle size of the gold oxide ore powder is 200-300 mesh.

7. The method for extracting oxidized gold ore by carbon-in-pulp cyanidation according to claim 1, characterized in that, The specific process in step 2) is as follows: the pretreated slurry is pumped into a 6-8 stage series leaching and adsorption system. Starting from the second stage leaching tank, sodium cyanide solution is added to control the free cyanide concentration of the entire system at 0.04%-0.06%, the pH value at more than 10.5, the carbon adsorbent concentration at 18-22 g / L, and the total leaching time of the slurry at 20-30 h to obtain gold-loaded material.

8. The method for extracting oxidized gold ore by carbon-in-pulp cyanidation according to claim 1, characterized in that: The carbon adsorbent is one or more of activated carbon, ion exchange resin, mesoporous silica, and diatomaceous earth, and contains at least activated carbon.

9. The method for extracting oxidized gold ore by carbon-in-pulp cyanidation according to claim 1, characterized in that, The activated sepiolite fiber is acidified sepiolite fiber. The specific steps for acidifying sepiolite fiber are as follows: after drying, the sepiolite fiber is added to a dilute hydrochloric acid solution and stirred at 60°C for 1 hour to remove carbonate and metal oxide impurities from the fiber surface.

10. The method for extracting oxidized gold ore by carbon-in-pulp cyanidation according to claim 1, characterized in that, The pyrometallurgical refining process in step 4) is as follows: the crude gold powder after impurity removal is mixed with flux at a weight ratio of 10:(1-1.5), and the resulting mixture is heated to 1100-1200℃ and smelted for 1-2 hours. Impurities and flux form slag that floats on the surface. After removing the slag, gold ingots are obtained. The solvents include borax, sodium carbonate, and quartz sand.

Images