A method for recovering gold and silver from high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction

Abstract

The present invention provides a method for recovering gold and silver from high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction. The method separates the main elements enriched in the leachate from the wet gold concentrate treatment process, achieving efficient and highly selective separation and recovery of gold and silver from a polymetallic acidic solution system in which impurity ions coexist. A homogeneous liquid-liquid extraction system is constructed using upper critical solution temperature-type functionalized ionic liquids (UCST-ILs). Temperature changes promote the formation and breaking of hydrogen bonds between anions and cations contained in the ionic liquid and water, thereby affecting the solution state by adjusting the number and strength of hydrogen bonds, thereby achieving reversible conversion between a homogeneous phase and two phases. The UCST-ILs used have high acid resistance and can effectively avoid the drawbacks of mass transfer limitations caused by high viscosity and excessive ionic liquid usage during liquid-liquid two-phase separation. The process involved in the present invention is simple, has low energy consumption, generates little waste liquid, and is a green process.

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 gold and silver from high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction. Background Art

[0002] High-arsenic gold concentrate is a complex ore that is difficult to smelt. This type of gold concentrate contains high arsenic, and gold and silver are often encapsulated by arsenopyrite. Conventional gold concentrate processing techniques result in extremely low gold and silver recovery rates. For example, the conventional two-stage roasting and pretreatment cyanide gold extraction process results in low recovery rates due to the encapsulation of some gold and silver by iron oxide. Furthermore, the production process produces large amounts of cyanide tailings and arsenic-containing gypsum slag, which is not in line with current national environmental protection policies. Using pyrometallurgical copper smelting processes yields higher gold and silver recovery rates, but requires a large amount of copper-containing material for blending, and strict requirements are imposed on the arsenic content of the blended ore. Excessive arsenic content can seriously affect the quality of the copper product and generate large amounts of arsenic-containing hazardous waste, making it difficult to process. Both of these processing methods are costly, time-consuming, complex, and labor-intensive. If gold and silver could be effectively separated from a polymetallic acidic solution system containing coexisting impurity ions efficiently and selectively after pretreatment, this would address these issues while also providing significant environmental and economic benefits, ultimately enabling the processing and utilization of difficult-to-process gold concentrates.

[0003] Prior reports have explored the resourceful processing and utilization of gold and silver from difficult-to-treat high-arsenic gold concentrates. For example, Chinese patent CN103966450A leaches and separates a series of metals, including copper, selenium, silver, barium, gold, antimony, tin, and platinum, by subjecting a copper anode slime to hot acid leaching, alkaline leaching, and chloride leaching. The barium is then removed and recovered in an open-circuit manner prior to gold and silver extraction through hot acid leaching, thereby increasing the recovery rate of gold and silver. Chinese patent CN103937977A discloses a comprehensive gold recovery process from arsenic-antimony gold concentrates. This process involves pre-alkaline leaching with the addition of a reducing agent to recover antimony, followed by two-stage roasting to recover arsenic and sulfur, and followed by acid leaching and cyanide leaching to recover gold. This process effectively increases the recovery rates of antimony (65%) and gold (80%).

[0004] Ionic liquids, a popular new medium for separation applications, have seen numerous reports on the extraction of metal ions from aqueous solutions. As excellent extractants, they have been widely used in separation processes. Ionic liquids possess unique properties such as non-volatility, high thermal and chemical stability, non-flammability, low vapor pressure, and high solubility. They are considered one of the "three major green solvents," along with supercritical fluids and aqueous two-phase solvents, which have potential applications. Several studies have demonstrated that ionic liquids have excellent extraction effects on metal ions from aqueous solutions, with separation efficiencies exceeding those of traditional organic solvents. Therefore, by leveraging the designability and diverse mechanisms of action of ionic liquids, they have been shown to effectively separate gold and silver from polymetallic acidic solutions containing coexisting impurity ions, improving their separation efficiency and selectivity, and possessing promising application prospects. Based on the extraction and separation process of ionic liquids for metal ion separation, further structural design and mechanism exploration of ionic liquids have effectively improved their efficiency and selectivity in gold and silver separation and recovery.

[0005] The literature [Extraction of Au(iii) from hydrochloric acid media using a novelamide-based ionic liquid, New Journal of Chemistry, 2022, 46, 19824-19833] proposed and studied pyrrole pyridinium-based ionic liquids functionalized with amide groups, and evaluated their separation and recovery efficiency of gold in hydrochloric acid media. After 4 cycles, an extraction efficiency of more than 90% was finally achieved. The paper [A separation strategy of Au(III), Pd(II) and Pt(IV) based on hydrophobic deep eutectic solvent from hydrochloric acid media, Journal of Molecular Liquids, 2022, 365, 120200] investigated the selective extraction and separation of Au(III), Pd(II), and Pt(IV) from secondary resource acidic leachate using a hydrophobic deep eutectic solvent based on lidocaine and thymol. The extraction process, maximum extraction capacity, and competitive extraction experiments were used to investigate the extraction and separation capabilities, and the ion association mechanism during the extraction process was proposed. Based on this, a separation process for Au(III), Pd(II), and Pt(IV) based on acidity and KSCN control was proposed, achieving recoveries of 97.8% for Au(III) and 99.9% for Pd(II).

[0006] In the processing of high-arsenic gold concentrates, which contain small amounts of precious metals such as gold and silver, conventional gold concentrate processing techniques result in extremely low gold and silver recovery rates, generating large amounts of cyanide tailings or arsenic-containing hazardous waste, making treatment difficult. Therefore, efficient separation and recovery of these tailings has significant environmental and economic benefits, improving existing process routes and ultimately achieving more efficient processing and utilization of difficult-to-treat gold concentrates. Summary of the Invention

[0007] In response to the shortcomings of the above-mentioned prior art methods, the present invention provides a method for recovering gold and silver from high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction. After a pretreatment operation, various metal elements are effectively classified and leached. The ionic liquid extraction and separation process is achieved through temperature response control to achieve reversible conversion between homogeneous and two-phase ionic liquids. Based on various synergistic modes such as functional group complexation and intermolecular interaction, a "UCST-ILs-water" temperature-controlled phase change system is constructed to allow rapid transfer of gold and silver, ultimately achieving efficient and highly selective separation and recovery of gold and silver from a polymetallic acidic solution system where impurity ions coexist. The method involves simple processes, low energy consumption, low waste liquid generation, and a green process, which not only reduces actual production costs but also fully utilizes resources, and has certain social benefits and economic value.

[0008] To achieve the above object, the present invention discloses a method for recovering gold and silver from high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction, which adopts the following technical scheme:

[0009] A method for recovering gold and silver from a high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction comprises the following steps:

[0010] (1) The refractory gold concentrate is subjected to conventional roasting, acid leaching and chloride leaching treatments to remove impurity elements such as sulfur and arsenic, and then the corresponding acid leaching solution and chloride leaching solution are obtained. The metal elements including gold and silver in the gold concentrate are immersed in the leaching solution, and the concentration of each metal element is measured;

[0011] (2) The leachate obtained in (1) is pumped into a reactor, stirred, and the pH is adjusted. A certain amount of UCST-ILs is added according to the amount of leachate, and the temperature of the reactor is gradually adjusted so that the ionic liquid-leachate system with different ionic liquid addition amounts reaches a certain concentration and gradually forms a homogeneous phase. In the homogeneous state, the interaction efficiency between gold and silver and the ionic liquid is effectively improved and their rapid transfer is achieved;

[0012] (3) After the homogeneous extraction in (2) is completed, the temperature is gradually lowered to a specified temperature to obtain two phases after the gold and silver are enriched. The acid-water phase is pumped back to the acid leaching system, and after replenishment, the acid leaching and chlorination leaching treatment in step (1) is continued;

[0013] (4) A stripping agent is used to selectively strip the gold and silver in the ionic liquid phase. The stripped ionic liquid is recycled back to step (2) to extract and separate the gold and silver in the leaching solution system again, and the cycle is repeated 5-10 times.

[0014] As a supplement, the refractory gold concentrate in step (1) has a gold content of 5-100 g / t and a silver content of 1-200 g / t.

[0015] As a supplement, UCST-ILs are ionic liquids composed of hydrophobic anions and functionalized 1,4,7-triazacyclononane cations modified with polyether groups, prepared by the following steps:

[0016] ① Mix a certain amount of 1,4,7-triazacyclononane and acetonitrile, add lithium bis(trifluoromethanesulfonyl)imide dropwise under stirring and reflux for 3 hours, filter and obtain the ionic liquid intermediate, wash it with distilled water several times, and then vacuum dry it for 48 hours;

[0017] ② The ionic liquid intermediate product in step ① is added to a high-pressure reactor containing an appropriate amount of ethanol solvent, and a certain amount of ethylene oxide is added. After sealing the reactor, nitrogen or inert gas is introduced for replacement. Under a certain pressure of nitrogen or inert atmosphere, the reaction is stirred at 30°C for 5 hours, and then the temperature is raised to 70-75°C and the reaction is continued for 6-10 hours. After the solvent is removed, polyether-modified 1,4,7-triazacyclononane bis(trifluoromethanesulfonyl)imide salt ionic liquids (UCST-ILs) with a certain degree of polymerization are obtained.

[0018] As a supplement, in the above step (2), the pH of the leaching solution is adjusted to 0.5-2, the ratio of UCST-ILs to the leaching solution is 1:50-1:120, and the reaction temperature is 20-80°C.

[0019] As a supplement, the stripping agent used in the above step (4) is potassium oxalate solution (gold stripping agent) or disulfide (silver stripping agent).

[0020] The technical features and beneficial effects of the present invention are as follows:

[0021] 1. This invention addresses the problem of recovering gold and silver from difficult-to-treat high-arsenic gold concentrate leachate by constructing a homogeneous liquid-liquid extraction system using UCST-ILs. This system can achieve reversible transitions between a homogeneous phase and a two-phase phase through appropriate thermal stimulation. Temperature changes promote the formation and breaking of hydrogen bonds between anions and cations in the ionic liquid and water, and the number and strength of these hydrogen bonds influence the solution state, resulting in a reversible transition from phase separation to a homogeneous phase. Furthermore, the ionic liquid exhibits high acid resistance. Using these UCST-ILs, the drawbacks of liquid-liquid two-phase separation processes, such as mass transfer limitations caused by high viscosity and excessive ionic liquid dosage, can be effectively avoided. This allows for efficient and highly selective separation and recovery of gold and silver from polymetallic acidic solutions containing coexisting impurity ions.

[0022] 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. DETAILED DESCRIPTION

[0023] The present invention is further described below with reference to specific examples. The present invention utilizes UCST-ILs to construct a series of UCST-IL-water homogeneous liquid-liquid extraction systems for recovering gold and silver from refractory gold concentrate leachate. However, the present invention is not limited to the following examples; variations thereof are encompassed within the technical scope of the present invention without departing from the spirit and scope of the present invention. The methods described in the examples are conventional unless otherwise noted; all materials and apparatus used are conventional and commercially available unless otherwise noted.

[0024] Example 1

[0025] A method for recovering gold and silver from a high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction comprises the following steps:

[0026] ① The high-arsenic gold concentrate with a gold content of 50g / t and a silver content of 100g / t was subjected to conventional roasting, acid leaching and chloride leaching to remove impurities such as sulfur and arsenic to obtain the corresponding leachate, and the concentration of each metal element was measured;

[0027] ② The leachate obtained in step ① was pumped into the reactor, stirred, and the pH was adjusted to 1. UCST-ILs with a reagent-liquid ratio of 1:50 were added according to the leachate volume. The temperature was gradually raised to 80°C to allow the UCST-ILs-leachate system to reach a homogeneous phase. Gold and silver were quickly transferred to the ionic liquid in the homogeneous state.

[0028] ③ After the extraction is completed, the homogeneous extract obtained in ② is gradually cooled to room temperature to obtain an ionic liquid phase and an acid aqueous solution phase after enrichment of gold and silver. The acid aqueous solution phase is pumped back to the leaching system and then continues with step ① acid leaching and chlorination leaching treatment;

[0029] ④ A stripping agent is used to selectively strip off the gold and silver in the ionic liquid phase. The stripped ionic liquid is recycled back to step ② to extract and separate the gold and silver in the leaching solution system again, and the cycle is repeated 5 times.

[0030] In this embodiment, the extraction recovery efficiency of gold is 98.6%, and the extraction recovery efficiency of silver is 98.2%.

[0031] Example 2

[0032] A method for recovering gold and silver from a high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction comprises the following steps:

[0033] ① The high-arsenic gold concentrate with a gold content of 50g / t and a silver content of 100g / t was subjected to conventional roasting, acid leaching and chloride leaching to remove impurities such as sulfur and arsenic to obtain the corresponding leachate, and the concentration of each metal element was measured;

[0034] ② The leachate obtained in step ① was pumped into the reactor, stirred, and the pH was adjusted to 0.5. UCST-ILs with a reagent-liquid ratio of 1:50 were added according to the leachate volume. The temperature was gradually raised to 80°C to allow the UCST-ILs-leachate system to reach a homogeneous phase. Gold and silver were quickly transferred to the ionic liquid in the homogeneous state.

[0035] ③ After the extraction is completed, the homogeneous extract obtained in ② is gradually cooled to room temperature to obtain an ionic liquid phase and an acid aqueous solution phase after enrichment of gold and silver. The acid aqueous solution phase is pumped back to the leaching system and then continues with step ① acid leaching and chlorination leaching treatment;

[0036] ④ A stripping agent is used to selectively strip off the gold and silver in the ionic liquid phase. The stripped ionic liquid is recycled back to step ② to extract and separate the gold and silver in the leaching solution system again, and the cycle is repeated 5 times.

[0037] In this embodiment, the extraction recovery efficiency of gold is 87.8%, and the extraction recovery efficiency of silver is 89.1%.

[0038] Example 3

[0039] A method for recovering gold and silver from a high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction comprises the following steps:

[0040] ① The high-arsenic gold concentrate with a gold content of 50g / t and a silver content of 100g / t was subjected to conventional roasting, acid leaching and chloride leaching to remove impurities such as sulfur and arsenic to obtain the corresponding leachate, and the concentration of each metal element was measured;

[0041] ② The leachate obtained in step ① was pumped into the reactor, stirred, and the pH was adjusted to 1. UCST-ILs with a reagent-liquid ratio of 1:100 was added according to the leachate volume. The temperature was gradually raised to 60°C to allow the UCST-ILs-leachate system to reach a homogeneous phase. Gold and silver were quickly transferred to the ionic liquid in the homogeneous state.

[0042] ③ After the extraction is completed, the homogeneous extract obtained in ② is gradually cooled to room temperature to obtain an ionic liquid phase and an acid aqueous solution phase after enrichment of gold and silver. The acid aqueous solution phase is pumped back to the leaching system and then continues with step ① acid leaching and chlorination leaching treatment;

[0043] ④ A stripping agent is used to selectively strip off the gold and silver in the ionic liquid phase. The stripped ionic liquid is recycled back to step ② to extract and separate the gold and silver in the leaching solution system again, and the cycle is repeated 5 times.

[0044] In this embodiment, the extraction recovery efficiency of gold is 93.2%, and the extraction recovery efficiency of silver is 93.5%.

[0045] Example 4

[0046] A method for recovering gold and silver from a high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction comprises the following steps:

[0047] ① The high-arsenic gold concentrate with a gold content of 50g / t and a silver content of 100g / t was subjected to conventional roasting, acid leaching and chloride leaching to remove impurities such as sulfur and arsenic to obtain the corresponding leachate, and the concentration of each metal element was measured;

[0048] ② The leachate obtained in step ① was pumped into the reactor, stirred, and the pH was adjusted to 1. UCST-ILs with a reagent-liquid ratio of 1:120 were added according to the leachate volume. The temperature was gradually raised to 45°C to allow the UCST-ILs-leachate system to reach a homogeneous phase. Gold and silver were quickly transferred to the ionic liquid in the homogeneous state.

[0049] ③ After the extraction is completed, the homogeneous extract obtained in ② is gradually cooled to room temperature to obtain an ionic liquid phase and an acid aqueous solution phase after enrichment of gold and silver. The acid aqueous solution phase is pumped back to the leaching system and then continues with step ① acid leaching and chlorination leaching treatment;

[0050] ④ A stripping agent is used to selectively strip off the gold and silver in the ionic liquid phase. The stripped ionic liquid is recycled back to step ② to extract and separate the gold and silver in the leaching solution system again, and the cycle is repeated 10 times.

[0051] In this embodiment, the extraction recovery efficiency of gold is 83.7%, and the extraction recovery efficiency of silver is 80.3%.

[0052] Example 5

[0053] A method for recovering gold and silver from a high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction comprises the following steps:

[0054] ① The high-arsenic gold concentrate with a gold content of 80g / t and a silver content of 150g / t was subjected to conventional roasting, acid leaching and chloride leaching to remove impurities such as sulfur and arsenic to obtain the corresponding leachate, and the concentration of each metal element was measured;

[0055] ② The leachate obtained in step ① was pumped into the reactor, stirred, and the pH was adjusted to 1.5. UCST-ILs with a reagent-liquid ratio of 1:50 was added according to the leachate volume. The temperature was gradually raised to 80°C to allow the UCST-ILs-leachate system to reach a homogeneous phase. Gold and silver were quickly transferred to the ionic liquid in the homogeneous state.

[0056] ③ After the extraction is completed, the homogeneous extract obtained in ② is gradually cooled to room temperature to obtain an ionic liquid phase and an acid aqueous solution phase after enrichment of gold and silver. The acid aqueous solution phase is pumped back to the leaching system and then continues with step ① acid leaching and chlorination leaching treatment;

[0057] ④ A stripping agent is used to selectively strip off the gold and silver in the ionic liquid phase. The stripped ionic liquid is recycled back to step ② to extract and separate the gold and silver in the leaching solution system again, and the cycle is repeated 6 times.

[0058] In this embodiment, the extraction recovery efficiency of gold is 96.5%, and the extraction recovery efficiency of silver is 94.4%.

[0059] Example 6

[0060] A method for recovering gold and silver from a high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction comprises the following steps:

[0061] ① The high-arsenic gold concentrate with a gold content of 100g / t and a silver content of 150g / t was subjected to conventional roasting, acid leaching and chloride leaching to remove impurities such as sulfur and arsenic to obtain the corresponding leachate, and the concentration of each metal element was measured;

[0062] ② The leachate obtained in step ① was pumped into the reactor, stirred, and the pH was adjusted to 1. UCST-ILs with a reagent-liquid ratio of 1:120 were added according to the leachate volume. The temperature was gradually raised to 50°C to allow the UCST-ILs-leachate system to reach a homogeneous phase. Gold and silver were quickly transferred to the ionic liquid in the homogeneous state.

[0063] ③ After the extraction is completed, the homogeneous extract obtained in ② is gradually cooled to room temperature to obtain an ionic liquid phase and an acid aqueous solution phase after enrichment of gold and silver. The acid aqueous solution phase is pumped back to the leaching system and then continues with step ① acid leaching and chlorination leaching treatment;

[0064] ④ A stripping agent is used to selectively strip off the gold and silver in the ionic liquid phase. The stripped ionic liquid is recycled back to step ② to extract and separate the gold and silver in the leaching solution system again, and the cycle is repeated 6 times.

[0065] In this embodiment, the extraction recovery efficiency of gold is 80.6%, and the extraction recovery efficiency of silver is 78.8%.

[0066] Example 7

[0067] A method for recovering gold and silver from a high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction comprises the following steps:

[0068] ① The high-arsenic gold concentrate with a gold content of 10g / t and a silver content of 60g / t was subjected to conventional roasting, acid leaching and chloride leaching to remove impurities such as sulfur and arsenic to obtain the corresponding leachate, and the concentration of each metal element was measured;

[0069] ② The leachate obtained in step ① was pumped into the reactor, stirred, and the pH was adjusted to 1. UCST-ILs with a reagent-liquid ratio of 1:120 were added according to the leachate volume. The temperature was gradually raised to 45°C to allow the UCST-ILs-leachate system to reach a homogeneous phase. Gold and silver were quickly transferred to the ionic liquid in the homogeneous state.

[0070] ③ After the extraction is completed, the homogeneous extract obtained in ② is gradually cooled to room temperature to obtain an ionic liquid phase and an acid aqueous solution phase after enrichment of gold and silver. The acid aqueous solution phase is pumped back to the leaching system and then continues with step ① acid leaching and chlorination leaching treatment;

[0071] ④ A stripping agent is used to selectively strip off the gold and silver in the ionic liquid phase. The stripped ionic liquid is recycled back to step ② to extract and separate the gold and silver in the leaching solution system again, and the cycle is repeated 6 times.

[0072] In this example, the gold extraction recovery efficiency was 97.2%, and the silver extraction recovery efficiency was 96.8%. 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 examples are merely illustrative of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention are intended to fall within the scope of protection defined by the claims.

Claims

1. A method for recovering gold and silver from a high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction, comprising the following steps: (1) The refractory gold concentrate is subjected to conventional roasting, acid leaching and chloride leaching treatments to remove the sulfur and arsenic impurities and then treated to obtain the corresponding acid leaching solution and chloride leaching solution. The metal elements including gold and silver in the gold concentrate are immersed in the leaching solution and the concentration of each metal element is measured; (2) The leachate obtained in (1) is pumped into a reactor, stirred, and the pH is adjusted. A certain amount of UCST-ILs is added according to the amount of leachate, and the temperature of the reactor is gradually adjusted so that the ionic liquid-leachate system with different ionic liquid addition amounts reaches a certain concentration and gradually forms a homogeneous phase. In the homogeneous state, the interaction efficiency between gold and silver and the ionic liquid is effectively improved and their rapid transfer is achieved; (3) After the homogeneous extraction in (2) is completed, the temperature is gradually lowered to a specified temperature to obtain two phases after the gold and silver are enriched. The acid-water phase is pumped back to the acid leaching system, and after replenishment, the acid leaching and chlorination leaching treatment in step (1) is continued; (4) using a stripping agent to selectively strip the gold and silver in the ionic liquid phase, and recycling the stripped ionic liquid back to step (2) to extract and separate the gold and silver in the leaching solution system again, for 5-10 cycles; The UCST-ILs are ionic liquids composed of a hydrophobic anion and a functionalized 1,4,7-triazacyclononane cation modified with a polyether group.

2. The method for recovering gold and silver from high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction according to claim 1, characterized in that: The refractory gold concentrate in step (1) has a gold content of 5-100 g / t and a silver content of 1-200 g / t.

3. The method for recovering gold and silver from high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction according to claim 1, characterized in that: The UCST-ILs in step (2) are prepared by the following steps: ① Mix a certain amount of 1,4,7-triazacyclononane and acetonitrile, add lithium bis(trifluoromethanesulfonyl)imide dropwise under stirring and reflux for 3 hours, filter and obtain the ionic liquid intermediate, wash it with distilled water several times, and then vacuum dry it for 48 hours; ② The ionic liquid intermediate product in ① is added to a high-pressure reactor containing an appropriate amount of ethanol solvent, and a certain amount of ethylene oxide is added. After sealing the reactor, nitrogen or inert gas is introduced for replacement. Under a certain pressure of nitrogen or inert atmosphere, the reaction is stirred at 30°C for 5 hours, and then the temperature is raised to 70-75°C and the reaction is continued for 6-10 hours. After the solvent is removed, a polyether-modified 1,4,7-triazacyclononane bis(trifluoromethanesulfonyl)imide salt ionic liquid with a certain degree of polymerization is obtained.

4. The method for recovering gold and silver from high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction according to claim 1, characterized in that: In step (2), the pH of the leaching solution is adjusted to 0.5-2, the ratio of UCST-ILs to the leaching solution is 1:50-1:120, and the reaction temperature is 20-80°C.

5. The method for recovering gold and silver from high-arsenic gold concentrate leachate by homogeneous liquid-liquid extraction according to claim 1, characterized in that: The gold stripping agent used in step (4) is potassium oxalate solution, and the silver stripping agent is disulfide.