A method for recovering copper and zinc from acid leaching solution of refractory gold concentrate

Abstract

The invention provides a method for recovering copper and zinc in a difficult-to-treat gold concentrate acid leaching solution, separates the main impurity elements copper and zinc enriched in the wet gold concentrate treatment acid leaching solution, adopts a "hydrophobic functionalized ionic liquid + di(2-ethylhexyl) phosphate (P204) + organic solvent" composite extractant, and achieves rapid phase transfer of copper and zinc ions through multiple synergistic effects such as complexation of ionic liquid functional groups, intermolecular interaction and solvent extraction, thereby realizing efficient extraction and recovery of copper and zinc ions in a complex strong acid solution system. The method involves a simple process, low energy consumption, less waste liquid generation, and a green process, which not only reduces the actual production cost, but also realizes full utilization of resources, and has certain social benefits and economic value.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive resource processing and utilization, and in particular to a method for recovering copper and zinc from acid leaching solution of refractory gold concentrate. Background Art

[0002] High-arsenic gold concentrate is a complex ore that is difficult to smelt. This type of concentrate contains small amounts of metallic elements such as copper and zinc. A two-stage roasting followed by cyanidation can effectively improve gold recovery. The roasting residue undergoes acid leaching before entering the cyanide leaching process, controlling the pH to 0.9-2. During the acid leaching process, impurities such as copper, zinc, and arsenic are introduced into the leaching solution, which circulates in a closed loop, concentrating the copper, zinc, and arsenic ions in the solution to increasing concentrations. If some of this liquid is carried over to the cyanide leaching system, it increases the consumption of auxiliary materials such as sodium hydroxide and sodium cyanide, deteriorates the quality of the gold mud, and significantly increases smelting costs. Furthermore, any liquid leakage during the process can contaminate the circulating water in the process. Efficiently separating the concentrated copper and zinc ions in the leaching solution would address these issues while also providing significant environmental and economic benefits. Conventional methods such as oxidation and flocculation can then be used to separate the arsenic from the solid and liquid phases, ultimately enabling the processing and utilization of the difficult-to-treat gold concentrate.

[0003] Prior art reports have reported on resource-based treatment and utilization of copper and zinc. For example, Chinese patent CN108265177A uses hydrometallurgical zinc smelting furnaces as raw materials and waste acid produced by nonferrous metallurgical enterprises as a leaching agent. After hydrolysis and arsenic precipitation, oxidation, and acid leaching, elements such as copper, zinc, iron, and arsenic in the zinc kiln slag enter the solution. A series of oxidation, neutralization, or displacement reactions are then performed to separate and solidify these elements in the leachate. By fully utilizing the compositional characteristics of hydrometallurgical zinc smelting furnace slag and waste acid, not only is the zinc, copper, and other valuable metals in the zinc kiln slag separated and recovered, but the waste acid is also simultaneously utilized for clean utilization. Chinese patent CN110819814A discloses a method for treating high-arsenic waste acid. This method uses acid leaching to extract copper and zinc, followed by a series of operations such as neutralization and displacement reactions to effectively reduce the copper and zinc content of the sulfuric acid slag and comprehensively recover and utilize the acid, copper, zinc, and arsenic in the high-arsenic waste acid. Ionic liquids, a popular new medium for separation applications, have been widely reported for the extraction of metal ions from aqueous solutions. As excellent extractants, they are widely used in separation processes. Ionic liquids are stable, non-volatile, and highly designable to suit specific tasks. Several studies have demonstrated their excellent extraction efficiency for metal ions in aqueous solutions, exceeding that of traditional organic solvents. Therefore, by leveraging the designability and diverse mechanisms of action of ionic liquids, they offer highly efficient extraction of copper and zinc, demonstrating promising application prospects.

[0004] The paper [Novel thiosalicylate-based ionic liquids for heavy metal extractions [J]. Journal of Hazardous Materials, 2016, 314, 164-171] proposed and studied novel ammonium- and phosphine-based ionic liquids with thiosalicylate derivatives as anions, and evaluated their extraction efficiency for heavy metals from aqueous solutions. Six ionic liquid extractants were synthesized and characterized, and their extraction efficiency for cadmium, copper, and zinc was studied. Liquid-liquid extraction of cadmium, copper, and zinc was performed using a model solution (pH = 7, 0.1 M CaCl2) after 1-24 hours using flame atomic absorption spectrometry.

[0005] The literature [Extraction of zinc metal ions from aqueous solution using ionic liquids [J]. Global NEST Journal, 2021, 23(1), 29-34] studies the extraction of transition heavy metal zinc and other metal ions such as copper and cadmium from aqueous hydrochloric acid solutions in the absence of a chelating agent using a novel hydrophobic ionic liquid. The ionic liquid, composed of 1-butyl-3-methylimidazolium cations and hexafluorophosphate anions, was shown to be capable of removing zinc (94.4% extraction efficiency) and other heavy metals such as copper and cadmium from aqueous solutions.

[0006] In the processing of high-arsenic gold concentrates, which contain small amounts of copper, zinc, and other metallic elements, a two-stage roasting followed by cyanidation treatment can effectively improve gold recovery. However, the roasting residue must undergo acid leaching before entering the cyanide leaching process. This acid leaching process produces a highly acidic acid solution with high copper, zinc, and arsenic content. Efficiently separating copper and zinc elements in this highly acidic, complex solution system is difficult, and traditional precipitation or solid-liquid separation methods are cumbersome, complex, and inefficient. Therefore, how to efficiently separate and recover these elements has good environmental and economic benefits, improve existing process routes, and ultimately achieve more efficient processing and utilization of difficult-to-treat gold concentrates. Summary of the Invention

[0007] In view of the shortcomings of the above-mentioned prior art methods, the present invention provides a recycling method. Refractory gold concentrate acid Immersion The method of separating copper and zinc is used to separate the main impurity elements copper and zinc enriched in the acid leaching liquid of wet gold concentrate treatment. The method involves simple process, low energy consumption, less waste liquid generation and green process, which not only reduces the actual production cost, but also realizes the full utilization of resources, and has certain social benefits and economic value.

[0008] To achieve the above object, the present invention discloses a method for recovering copper and zinc from acid leaching solution of refractory gold concentrate, which adopts the following technical scheme:

[0009] A method for separating and recovering copper and zinc from a refractory gold concentrate acid leachate, comprising the following steps:

[0010] (1) The slag from the two-stage roasting of the refractory gold concentrate is subjected to acid leaching treatment, and the pH is controlled at 0.9-2. Impurity elements such as copper and zinc are leached into the acid leaching solution through the acid leaching process, and the acid leaching solution is circulated in a closed circuit to increase the enrichment concentration of impurities in the acid leaching solution;

[0011] (2) The acid leaching liquid obtained in the workshop is passed into a stirring tank for stirring, and a certain amount of composite extractant is pumped into it. After stirring at an appropriate temperature, it is allowed to stand for liquid-liquid phase separation, and finally an upper composite extractant phase (oil phase) in which copper and zinc ions are extracted and a lower acid aqueous solution phase are obtained;

[0012] (3) After the two phases obtained in (2) are separated, the lower layer is pumped back to the acid leaching system, and after replenishing the new acid solution, the roasting slag is further acid leached to enrich the metal elements such as copper and zinc. The upper layer is continued to be used as an extractant in the stirring tank to extract the acid leaching liquid to be treated. After the end, the above operation is continued;

[0013] (4) After a certain number of cycles, liquid-liquid phase separation is performed, and the raffinate phase obtained in (3) is oxidized, flocculated, and subjected to conventional methods to separate arsenic from the solid and liquid phases, and the recovered copper and zinc are obtained in the extract phase.

[0014] As a supplement, the acid leaching solution in the above steps (1) to (3) is obtained in a stable state after running for 102-484 hours, and the copper concentration in the acid leaching solution is greater than 300 mg / L and the zinc concentration is greater than 3000 mg / L.

[0015] In addition, the hydrophobic functionalized ionic liquid is an ionic liquid composed of a hydrophobic anion and a hydroxyl functionalized cation containing a thiourea group, which is prepared by the following steps. The preparation process of this type of ionic liquid is as follows:

[0016] ④ Evenly mix 1-(3-aminopropyl)imidazole and acetonitrile, and add dropwise a solution of isopropyl isothiocyanate in acetonitrile under stirring to react; filter to obtain the white powdery intermediate 1-(3-isopropylthioureidopropyl)imidazole and dry it;

[0017] ⑤ Dissolve an appropriate amount of bromoethanol in acetonitrile, add the 1-(3-isopropylthioureidopropyl)imidazole powder obtained in ①, and stir. After the reaction, remove the acetonitrile and spin to obtain a viscous liquid. Dissolve it in deionized water and wash with anhydrous ether. After spinning, remove the solvent to obtain the intermediate product, 1-hydroxyethyl-3-isopropylthioureidopropylimidazole bromide.

[0018] ⑥ The 1-hydroxyethyl-3-isopropylthiourea propyl imidazole bromide obtained in step ② is re-dissolved in deionized water and ion-exchanged with a hydrophobic anionic salt (lithium bistrifluoromethanesulfonyl imide or potassium hexafluorophosphate) to produce the corresponding ionic liquid. Two separate phases are obtained. After removing the upper phase, the lower phase is washed with water until no precipitation occurs upon addition of AgNO₃ to the water. The water is then removed by rotary evaporation to obtain the 1-hydroxyethyl-3-isopropylthiourea propyl imidazole bistrifluoromethanesulfonyl imide ionic liquid or the 1-hydroxyethyl-3-isopropylthiourea propyl imidazole hexafluorophosphate ionic liquid extractant.

[0019] As a supplement, the acid used in the acid leaching operation in the above step (1) is a sulfuric acid solution of a certain concentration or waste acid produced in a related process; during the acid leaching process, the pH of the acid leaching solution is controlled between 0.9 and 2.

[0020] As a supplement, the composite extractant used in the above step (2) is a homogeneous composite extractant obtained by "hydrophobic functionalized ionic liquid + di(2-ethylhexyl) phosphate (P204) + dichloromethane / ethyl acetate solvent" in a certain proportion.

[0021] As a supplement, in the above step (2), the mass content of P204 in the composite extractant is between 5% and 35%; the mass content of the ionic liquid is between 25% and 5%.

[0022] As a supplement, in the above step (2), the ratio of the composite extractant to the acid leaching solution is 1:10-1:50.

[0023] As a supplement, the extraction time in the above step (2) is 1-60 min.

[0024] As a supplement, the extraction temperature in the above step (2) is 20-50°C.

[0025] In addition, the number of cycles in the above step (3) is 5-12 times.

[0026] The technical features and beneficial effects of the present invention are as follows:

[0027] 1. This invention targets the recovery of small amounts of copper and zinc impurities from difficult-to-treat high-arsenic gold concentrates. It utilizes a composite extractant consisting of a hydrophobic functionalized ionic liquid, di(2-ethylhexyl) phosphate (P2O4), and an organic solvent to treat the acid leachate. Through the effective design of the ionic liquid's functional structure and the rational combination of P2O4 and the solvent, it achieves highly efficient extraction and separation of copper and zinc ions in complex solution systems under strongly acidic conditions. This process not only recovers the copper and zinc valuable metals, but also effectively avoids potential problems associated with subsequent cyanide leaching systems.

[0028] 2. The method of the present invention involves a simple process, low energy consumption, little waste liquid generation, and an environmentally friendly process, which not only reduces actual production costs but also achieves full utilization of resources, thus having certain social benefits and economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0030] Figure 1 It is a schematic diagram of the principle of the present invention. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] The present invention is further described below with reference to specific examples. This invention utilizes a composite extractant system consisting of a hydrophobic functionalized ionic liquid, di(2-ethylhexyl) phosphate (P204), and an organic solvent to recover copper and zinc from acid leachate from refractory gold concentrate. However, this invention is not limited to the following examples; variations within the spirit and scope of the present invention are encompassed. The methods described in the examples are conventional unless otherwise noted; all materials and equipment used are currently available and commercially available.

[0033] A hydroxyl-functionalized hydrophobic ionic liquid containing thiourea complexing sites and a P204 acidic phosphate extractant were used to simultaneously extract copper and zinc ions. Dichloromethane or ethyl acetate, which have good solubility for both the ionic liquid and P204, was selected as the composite extractant solvent. The study found that the "hydrophobic ionic liquid-acidic phosphate P204-solvent" extraction system exhibited excellent extraction performance for copper and zinc.

[0034] Example 1

[0035] A method for recovering copper and zinc from a refractory gold concentrate acid leachate comprises the following steps:

[0036] ① The gold concentrate roasting slag after two-stage roasting in the workshop is subjected to acid leaching treatment. The pH is controlled at 1. Impurity elements such as copper and zinc are leached into the acid leaching solution during the acid leaching process. After closed-circuit circulation, the concentrations of copper ions and zinc ions enriched in the acid leaching solution are copper concentration = 320 mg / L and zinc concentration = 3500 mg / L respectively;

[0037] ② The acid extract was passed into a stirring tank for stirring, and a composite extractant (ILs: P204: ethyl acetate = 5:35:60, wt%) was pumped into the tank at a reagent-liquid ratio (O / A) of 1:10. The mixture was stirred and extracted at 25°C for 20 minutes, and then allowed to stand for liquid-liquid phase separation to obtain an upper extract phase (composite extractant phase) rich in copper and zinc metal ions and a lower acid aqueous solution phase;

[0038] ③ The lower acid aqueous solution phase is pumped back to the acid leaching system. After replenishing the new acid solution, the roasted slag is continued to be acid leached to enrich copper, zinc and other elements. The upper composite extractant phase is continued to be used as an extractant in the stirring tank to extract the acid leaching solution. The above operation is repeated 5 times;

[0039] ④ After 5 cycles, perform liquid-liquid phase separation and calculate the extraction rates of copper and zinc recovered in the extraction phase.

[0040] The copper ion extraction and separation efficiency in the acid leaching solution in this embodiment is 98.5%, and the zinc ion extraction and separation efficiency is 98.9%.

[0041] Example 2

[0042] A method for recovering copper and zinc from a refractory gold concentrate acid leachate comprises the following steps:

[0043] ① The gold concentrate roasting slag after two-stage roasting in the workshop is subjected to acid leaching treatment, and the pH is controlled at 1.5. Impurity elements such as copper and zinc are leached into the acid leaching solution during the acid leaching process. After closed-circuit circulation, the concentrations of copper ions and zinc ions enriched in the acid leaching solution are copper concentration = 320 mg / L and zinc concentration = 3500 mg / L respectively;

[0044] ② The acid extract was passed into a stirring tank for stirring, and a composite extractant (ILs: P204: ethyl acetate = 25:5:70, wt%) was pumped into the tank at a ratio of 1:10. The mixture was stirred and extracted at 25°C for 20 minutes, and then allowed to stand for liquid-liquid phase separation to obtain an upper extract phase (composite extractant phase) rich in copper and zinc metal ions and a lower acid aqueous solution phase.

[0045] ③ The lower acid aqueous solution phase is pumped back to the acid leaching system. After replenishing the new acid solution, the roasted slag is continued to be acid leached to enrich copper, zinc and other elements. The upper composite extractant phase is continued to be used as an extractant in the stirring tank to extract the acid leaching solution. The above operation is repeated 5 times;

[0046] ④ After 5 cycles, perform liquid-liquid phase separation and calculate the extraction rates of copper and zinc recovered in the extraction phase.

[0047] The copper ion extraction and separation efficiency in the acid leaching solution in this embodiment is 99.8%, and the zinc ion extraction and separation efficiency is 90.1%.

[0048] Example 3

[0049] A method for recovering copper and zinc from a refractory gold concentrate acid leachate comprises the following steps:

[0050] ① The gold concentrate roasting slag after two-stage roasting in the workshop is subjected to acid leaching treatment, and the pH is controlled at 2. During the acid leaching process, impurity elements such as copper and zinc are leached into the acid leaching solution. After closed-circuit circulation, the concentrations of copper ions and zinc ions enriched in the acid leaching solution are copper concentration = 320 mg / L and zinc concentration = 3500 mg / L respectively;

[0051] ② The acid extract was passed into a stirring tank for stirring, and a composite extractant (ILs: P204: ethyl acetate = 5:35:60, wt%) was pumped into the tank at a reagent-liquid ratio (O / A) of 1:10. The mixture was stirred and extracted at 25°C for 20 minutes, and then allowed to stand for liquid-liquid phase separation to obtain an upper extract phase (composite extractant phase) rich in copper and zinc metal ions and a lower acid aqueous solution phase;

[0052] ③ The lower acid aqueous solution phase is pumped back to the acid leaching system. After replenishing the new acid solution, the roasted slag is continued to be acid leached to enrich copper, zinc and other elements. The upper composite extractant phase is continued to be used as an extractant in the stirring tank to extract the acid leaching solution. The above operation is repeated 5 times;

[0053] ④ After 5 cycles, perform liquid-liquid phase separation and calculate the extraction rates of copper and zinc recovered in the extraction phase.

[0054] The copper ion extraction and separation efficiency in the acid leaching solution in this embodiment is 99.0%, and the zinc ion extraction and separation efficiency is 99.2%.

[0055] Example 4

[0056] A method for recovering copper and zinc from a refractory gold concentrate acid leachate comprises the following steps:

[0057] ① The gold concentrate roasting slag after two-stage roasting in the workshop is subjected to acid leaching treatment, and the pH is controlled at 2. During the acid leaching process, impurity elements such as copper and zinc are leached into the acid leaching solution. After closed-circuit circulation, the concentrations of copper ions and zinc ions enriched in the acid leaching solution are copper concentration = 320 mg / L and zinc concentration = 3500 mg / L respectively;

[0058] ② The acid extract was passed into a stirring tank for stirring, and a composite extractant (ILs: P204: ethyl acetate = 5:35:60, wt%) was pumped into the tank at a reagent-liquid ratio (O / A) of 1:50. The mixture was stirred and extracted at 25°C for 20 minutes, and then allowed to stand for liquid-liquid phase separation to obtain an upper extract phase (composite extractant phase) rich in copper and zinc metal ions and a lower acid aqueous solution phase;

[0059] ③ The lower acid aqueous solution phase is pumped back to the acid leaching system. After replenishing the new acid solution, the roasted slag is continued to be acid leached to enrich copper, zinc and other elements. The upper composite extractant phase is continued to be used as an extractant in the stirring tank to extract the acid leaching solution. The above operation is repeated 5 times;

[0060] ④ After 5 cycles, perform liquid-liquid phase separation and calculate the extraction rates of copper and zinc recovered in the extraction phase.

[0061] The copper ion extraction and separation efficiency in the acid leaching solution in this embodiment is 97.5%, and the zinc ion extraction and separation efficiency is 97.9%.

[0062] Example 5

[0063] A method for recovering copper and zinc from a refractory gold concentrate acid leachate comprises the following steps:

[0064] ① The gold concentrate roasting slag after two-stage roasting in the workshop is subjected to acid leaching treatment, and the pH is controlled at 2. During the acid leaching process, impurity elements such as copper and zinc are leached into the acid leaching solution. After closed-circuit circulation, the concentrations of copper ions and zinc ions enriched in the acid leaching solution are copper concentration = 320 mg / L and zinc concentration = 3500 mg / L respectively;

[0065] ② The acid extract was passed into a stirring tank for stirring, and a composite extractant (ILs: P204: ethyl acetate = 10:20:70, wt%) was pumped into the tank at a reagent-liquid ratio (O / A) of 1:30. The mixture was stirred and extracted at 25°C for 20 minutes, and then allowed to stand for liquid-liquid phase separation to obtain an upper extract phase (composite extractant phase) rich in copper and zinc metal ions and a lower acid aqueous solution phase;

[0066] ③ The lower acid aqueous solution phase is pumped back to the acid leaching system. After replenishing the new acid solution, the roasted slag is continued to be acid leached to enrich copper, zinc and other elements. The upper composite extractant phase is continued to be used as an extractant in the stirring tank to extract the acid leaching solution. The above operation is repeated 5 times;

[0067] ④ After 5 cycles, perform liquid-liquid phase separation and calculate the extraction rates of copper and zinc recovered in the extraction phase.

[0068] In this embodiment, the copper ion extraction and separation efficiency in the acid leaching solution is 98.5%, and the zinc ion extraction and separation efficiency is 97.9%.

[0069] Example 6

[0070] A method for recovering copper and zinc from a refractory gold concentrate acid leachate comprises the following steps:

[0071] ① The gold concentrate roasting slag after two-stage roasting in the workshop is subjected to acid leaching treatment, and the pH is controlled at 2. During the acid leaching process, impurity elements such as copper and zinc are leached into the acid leaching solution. After closed-circuit circulation, the concentrations of copper ions and zinc ions enriched in the acid leaching solution are copper concentration = 320 mg / L and zinc concentration = 3500 mg / L respectively;

[0072] ② The acid extract was passed into a stirring tank for stirring, and a composite extractant (ILs: P204: ethyl acetate = 10:20:70, wt%) was pumped into the tank at a reagent-liquid ratio (O / A) of 1:30. The mixture was stirred and extracted at 25°C for 20 minutes, and then allowed to stand for liquid-liquid phase separation to obtain an upper extract phase (composite extractant phase) rich in copper and zinc metal ions and a lower acid aqueous solution phase;

[0073] ③ The lower acid solution phase is pumped back to the acid leaching system. After replenishing the new acid solution, the roasted slag is continued to be acid leached to enrich copper, zinc and other elements. The upper composite extractant phase is continued to be used as an extractant in the stirring tank to extract the acid leaching solution. The above operation is repeated 12 times;

[0074] ④ After 12 cycles, perform liquid-liquid phase separation and calculate the extraction rates of copper and zinc recovered in the extraction phase.

[0075] The copper ion extraction and separation efficiency in the acid leaching solution in this embodiment is 95.5%, and the zinc ion extraction and separation efficiency is 93.9%.

[0076] Example 7

[0077] A method for recovering copper and zinc from a refractory gold concentrate acid leachate comprises the following steps:

[0078] ① The gold concentrate roasting slag after two-stage roasting in the workshop is subjected to acid leaching treatment, and the pH is controlled at 1.5. During the acid leaching process, impurity elements such as copper and zinc are leached into the acid leaching solution. After closed-circuit circulation, the concentrations of copper ions and zinc ions enriched in the acid leaching solution are copper concentration = 300 mg / L and zinc concentration = 3000 mg / L respectively;

[0079] ② The acid extract was passed into a stirring tank for stirring, and a composite extractant (ILs: P204: ethyl acetate = 15:15:70, wt%) was pumped into the tank at a ratio of 1:30. The mixture was stirred and extracted at 25°C for 10 minutes, and then allowed to stand for liquid-liquid phase separation to obtain an upper extract phase (composite extractant phase) rich in copper and zinc metal ions and a lower acid aqueous solution phase.

[0080] ③ The lower acid solution phase is pumped back to the acid leaching system. After replenishing the new acid solution, the roasted slag is continued to be acid leached to enrich copper, zinc and other elements. The upper composite extractant phase is continued to be used as an extractant in the stirring tank to extract the acid leaching solution. The above operation is repeated 12 times;

[0081] ④ After 12 cycles, perform liquid-liquid phase separation and calculate the extraction rates of copper and zinc recovered in the extraction phase.

[0082] In this embodiment, the copper ion extraction and separation efficiency in the acid leaching solution is 94.8%, and the zinc ion extraction and separation efficiency is 94.9%.

[0083] Example 8

[0084] A method for recovering copper and zinc from a refractory gold concentrate acid leachate comprises the following steps:

[0085] ① The gold concentrate roasting slag after two-stage roasting in the workshop is subjected to acid leaching treatment, and the pH is controlled at 2. During the acid leaching process, impurity elements such as copper and zinc are leached into the acid leaching solution. After closed-circuit circulation, the concentrations of copper ions and zinc ions enriched in the acid leaching solution are copper concentration = 350mg / L and zinc concentration = 3900mg / L respectively;

[0086] ② The acid extract was passed into a stirring tank for stirring, and a composite extractant (ILs: P204: ethyl acetate = 15:15:70, wt%) was pumped into the tank at a ratio of 1:40. The mixture was stirred and extracted at 45°C for 20 minutes, and then allowed to stand for liquid-liquid phase separation to obtain an upper extract phase (composite extractant phase) rich in copper and zinc metal ions and a lower acid aqueous solution phase.

[0087] ③ The lower acid aqueous solution phase is pumped back to the acid leaching system. After replenishing the new acid solution, the roasted slag is continued to be acid leached to enrich copper, zinc and other elements. The upper composite extractant phase is continued to be used as an extractant in the stirring tank to extract the acid leaching solution. The above operation is repeated 5 times;

[0088] ④ After 5 cycles, perform liquid-liquid phase separation and calculate the extraction rates of copper and zinc recovered in the extraction phase.

[0089] In this embodiment, the copper ion extraction and separation efficiency in the acid leaching solution was 94.7%, and the zinc ion extraction and separation efficiency was 94.2%. The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solution of the present invention by those skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for separating and recovering copper and zinc from a refractory gold concentrate acid leaching solution, comprising the following steps: (1) The slag of the refractory gold concentrate after two-stage roasting is subjected to acid leaching treatment, and the pH is controlled to be 0.9-2. The impurity elements of copper and zinc are leached into the acid leaching solution through the acid leaching process, and the acid leaching solution is circulated in a closed circuit to increase its enrichment concentration in the acid leaching solution; (2) The acid leaching liquid obtained in the workshop is passed into a stirring tank for stirring, and a certain amount of composite extractant is pumped into the stirring tank. After stirring at an appropriate temperature, the mixture is allowed to stand for liquid-liquid phase separation, and finally an upper composite extractant phase in which copper and zinc ions are extracted and a lower acid aqueous solution phase are obtained; (3) After the two phases obtained in (2) are separated, the lower phase is pumped back to the acid leaching system, and after replenishing the new acid solution, the roasting slag is further acid leached to enrich the copper and zinc metal elements, and the upper phase is continued to be used as an extractant in the stirring tank to extract the acid leaching solution to be treated, and the above operation is continued after completion; (4) After a certain number of cycles, liquid-liquid phase separation is performed, and the raffinate phase obtained in (3) is oxidized and flocculated by conventional methods to separate arsenic from the solid and liquid, and copper and zinc are recovered in the extract phase; The composite extractant is obtained by homogeneously compounding a hydrophobic functionalized ionic liquid, di(2-ethylhexyl) phosphate (P204) and a dichloromethane / ethyl acetate solvent; The hydrophobic functionalized ionic liquid is an ionic liquid composed of a hydrophobic anion and a hydroxyl functionalized cation containing a thiourea group, which is prepared by the following steps. The preparation process of the ionic liquid is as follows: ① Evenly mix 1-(3-aminopropyl)imidazole and acetonitrile, and dropwise add isopropyl isothiocyanate dissolved in acetonitrile under stirring to react; filter to obtain the white powdery intermediate 1-(3-isopropylthioureidopropyl)imidazole and dry; ② Dissolve an appropriate amount of bromoethanol in acetonitrile, add the 1-(3-isopropylthioureapropyl)imidazole powder obtained in ① and stir, remove the acetonitrile after the reaction to obtain a viscous liquid; dissolve it in deionized water and wash it with anhydrous ether, remove the solvent and obtain the intermediate product 1-hydroxyethyl-3-isopropylthioureapropylimidazole bromide; ③ The 1-hydroxyethyl-3-isopropylthiourea propyl imidazole bromide obtained in ② is dissolved again with deionized water, and ion exchange is carried out with a hydrophobic anion salt to prepare a corresponding ionic liquid, wherein the hydrophobic anion salt is selected from lithium bis(trifluoromethanesulfonyl)imide or potassium hexafluorophosphate; two phases are obtained, and the upper phase is removed and the lower phase is washed with water until no precipitation occurs when AgNO3 is added to the water; water is removed by rotary evaporation to obtain 1-hydroxyethyl-3-isopropylthiourea propyl imidazole bis(trifluoromethanesulfonyl)imide salt ionic liquid or 1-hydroxyethyl-3-isopropylthiourea propyl imidazole hexafluorophosphate ionic liquid extractant.

2. The method for separating and recovering copper and zinc from acid leaching solution of refractory gold concentrate according to claim 1, characterized in that: The acid leaching solution in the steps (1) to (3) is obtained in a stable state after running for 102-484 hours, and the copper concentration in the acid leaching solution is greater than 300 mg / L and the zinc concentration is greater than 3000 mg / L.

3. The method for separating and recovering copper and zinc from acid leaching solution of refractory gold concentrate according to claim 1, characterized in that: The acid used in the acid leaching operation in step (1) is a sulfuric acid solution of a certain concentration or waste acid produced in a related process; during the acid leaching process, the pH of the acid leaching solution is controlled between 0.9 and 2.

4. The method for separating and recovering copper and zinc from acid leaching solution of refractory gold concentrate according to claim 1, characterized in that: In the step (2), the mass content of P204 in the composite extractant is between 5% and 35%; the mass content of the ionic liquid is between 25% and 5%.

5. The method for separating and recovering copper and zinc from acid leaching solution of refractory gold concentrate according to claim 1, characterized in that: In step (2), the ratio of the composite extractant to the acid leaching solution is 1:10-1:

50.

6. The method for separating and recovering copper and zinc from acid leaching solution of refractory gold concentrate according to claim 1, characterized in that: The extraction time in step (2) is 1-60 min.

7. The method for separating and recovering copper and zinc from acid leaching solution of refractory gold concentrate according to claim 1, characterized in that: The extraction temperature in step (2) is 20-50°C.

8. The method for separating and recovering copper and zinc from acid leaching solution of refractory gold concentrate according to claim 1, characterized in that: The number of cycles in step (3) is 5-12 times.

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