A room temperature ionic liquid for separating gold and a preparation method and application thereof

Abstract

This invention discloses a room-temperature ionic liquid for separating gold, its preparation method, and its application, belonging to the field of precious metal separation technology. This invention provides a room-temperature ionic liquid for separating gold, wherein the cation is a tetramethylguanidine derivative cation, and the anion is a bis(trifluoromethanesulfonyl)imide anion; the structural formula of the tetramethylguanidine derivative cation is as follows: wherein R1 and R2 are both selected from C6-C6. 10 One of the alkyl groups. The guanidine ionic liquid provided by this invention has a novel structure and good stability. As an extractant, this guanidine ionic liquid exhibits excellent extraction efficiency and selectivity for gold, with an extraction rate reaching 99.6%. Furthermore, this guanidine ionic liquid is a room-temperature ionic liquid, avoiding the use of volatile and toxic organic reagents as diluents during gold extraction, making it environmentally friendly and in line with green chemistry principles.

Description

Technical Field

[0001] This invention belongs to the field of precious metal separation technology, and relates to the synthesis of a novel guanidine ionic liquid and a method for selectively extracting gold using it as an extractant. Specifically, it relates to a room temperature ionic liquid for separating gold, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Patent CN1196095 discloses a method for recovering gold using an extractant with guanidine functional groups. The extractant used is a solid adsorbent loaded with guanidine functional groups. The extraction time is long, with the adsorption process requiring 16-24 hours and the elution process requiring 24 or 48 hours, resulting in low gold recovery efficiency.

[0004] Currently, industrial gold extraction and separation mainly rely on solvent extraction. Solvent extraction offers advantages such as simplicity, ease of operation, and the ability to be continuously produced. However, it also has disadvantages, including solvent evaporation and the use of toxic diluents, which pollute the environment. With the development of green chemistry and the emergence of room-temperature ionic liquids, traditional solvent extraction has been revitalized. Ionic liquids possess advantages such as low volatility, high conductivity, high viscosity, stability, and high designability, thus showing promising application prospects in extraction separation, catalysis, and electrolytes.

[0005] However, the inventors' research revealed that most guanidine ionic liquids currently have two main applications. One is for the extraction and separation of organic compounds. For example, patent CN114105853A discloses a tetramethylguanidine ionic liquid for separating neutral nitrogen compounds from coal tar, patent CN116440538A discloses a guanidine ionic liquid for extracting refined tea tree oil, and patent CN106404707A discloses a guanidine acetate ionic liquid for extracting petroleum and animal / vegetable oils from water. The other application is for separating rare earth metals, such as patent CN116623020A which discloses a hydrophobic guanidine ionic liquid for extracting and separating rare earth elements lanthanum and yttrium. Currently, no guanidine ionic liquids have been reported for separating gold. Therefore, to expand the applications of guanidine ionic liquids, there is an urgent need to develop a new guanidine ionic liquid for separating gold. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a room-temperature ionic liquid for separating gold, its preparation method, and its application. The room-temperature ionic liquid provided by the present invention has a novel structure, good stability, and exhibits excellent extraction effect and selectivity for gold as an extractant.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a room-temperature ionic liquid for separating gold, wherein the cation is a tetramethylguanidine derivative cation and the anion is a bis(trifluoromethanesulfonyl)imide anion;

[0009] The structural formula of the tetramethylguanidinyl derivative cation is as follows:

[0010]

[0011] R1 and R2 are both selected from C6-C 10 One of the alkyl groups.

[0012] Preferably, R1 and R2 are the same substituents.

[0013] A second aspect of the present invention provides a method for preparing the above-mentioned room-temperature ionic liquid, comprising the following steps:

[0014] Tetramethylguanidine, potassium carbonate, phase transfer agent, and functional reagent are dissolved in an organic solvent and reacted under a protective atmosphere by heating.

[0015] After the reaction was completed, the mixture was filtered and deionized water was added to the filtrate. The filtrate was extracted, saturated sodium bromide was added to the aqueous phase, and the mixture was extracted. The organic phase was dried and the solvent was removed to obtain the intermediate.

[0016] The intermediate was dissolved in deionized water, and lithium bis(trifluoromethanesulfonyl)imide salt was added. The mixture was stirred at room temperature and centrifuged to obtain a room temperature ionic liquid for gold separation.

[0017] The phase transfer agent is tetrabutylammonium bromide;

[0018] The functional reagent is either bromooctane or 2-ethylhexyl bromide.

[0019] Preferably, the organic solvent includes, but is not limited to, acetonitrile.

[0020] Preferably, the molar ratio of tetramethylguanidine, potassium carbonate and functional reagent is 1:3-5:1-1.5; the molar ratio of tetramethylguanidine to phase transfer agent is 3-5:1.

[0021] Preferably, the heating reaction is carried out at a temperature of 60-70°C.

[0022] A third aspect of the present invention provides the application of the above-described room temperature ionic liquid or the room temperature ionic liquid prepared by the above-described preparation method in the extraction of gold (III).

[0023] A fourth aspect of the present invention provides a method for extracting gold (III), comprising the following steps:

[0024] The room-temperature ionic liquid described above or the room-temperature ionic liquid prepared by the above method is mixed with a gold (III)-containing aqueous phase, and after extraction equilibrium, the two phases are separated by centrifugation.

[0025] Preferably, the concentration of hydrochloric acid in the gold (III) aqueous phase is 0.1-5 mol / L.

[0026] Preferably, the concentration of gold in the gold (III) aqueous phase is 980-990 mg / L, and the ratio of the room temperature ionic liquid to the gold (III) aqueous phase is 1-50:1, mg / mL.

[0027] Preferably, the extraction temperature is 25℃-65℃ and the extraction time is 1-60min.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention provides a room-temperature ionic liquid for separating gold, wherein the cation is a tetramethylguanidine derivative cation and the anion is a bis(trifluoromethanesulfonyl)imide anion. The guanidine ionic liquid provided by this invention has a novel structure and good stability. As an extractant, this guanidine ionic liquid exhibits excellent extraction efficiency and selectivity for gold, achieving an extraction rate of up to 99.6%. Furthermore, since this guanidine ionic liquid is room-temperature ionic, it avoids the use of volatile and toxic organic reagents as diluents during gold extraction, making it environmentally friendly and in line with green chemistry principles. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 The effect of temperature on the extraction of gold (III) by guanidine ionic liquids. Detailed Implementation

[0032] This invention provides a room temperature ionic liquid for separating gold, wherein the cation is a tetramethylguanidine derivative cation and the anion is a bis(trifluoromethanesulfonyl)imide anion;

[0033] The structural formula of the tetramethylguanidinyl derivative cation is as follows:

[0034]

[0035] R1 and R2 are both selected from C6-C 10 One of the alkyl groups.

[0036] The bis(trifluoromethanesulfonyl)imide anion described in this invention is derived from bis(trifluoromethanesulfonyl)imide lithium salt, which is a commercially available product, and its structural formula is as follows:

[0037]

[0038] The room-temperature ionic liquid for separating gold provided by this invention is a guanidine-based ionic liquid, wherein the structural formula of the ion pair is as follows:

[0039]

[0040] Both R1 and R2 are selected from C6-C 10 One of the alkyl groups. The room-temperature ionic liquid provided by this invention has a novel structure and good stability, and as an extractant, it exhibits excellent extraction effect and selectivity for gold.

[0041] In some embodiments of the present invention, the C6-C 10 Alkyl groups include C6-C 10 Straight-chain alkyl groups and branched alkyl groups. The C6-C... 10 The straight-chain alkyl groups include n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl. The C6-C... 10 Branched alkyl groups include, but are not limited to, 2-ethylhexyl.

[0042] In some embodiments of the present invention, R1 and R2 are the same substituents.

[0043] In some embodiments of the present invention, R1 and R2 are both n-octyl groups.

[0044] In some embodiments of the present invention, R1 and R2 are both 2-ethylhexyl.

[0045] A second aspect of the present invention provides a method for preparing the above-mentioned room-temperature ionic liquid, comprising the following steps:

[0046] Tetramethylguanidine, potassium carbonate, phase transfer agent, and functional reagent are dissolved in an organic solvent and reacted under a protective atmosphere by heating.

[0047] After the reaction was completed, the mixture was filtered and deionized water was added to the filtrate. The filtrate was extracted, saturated sodium bromide was added to the aqueous phase, and the mixture was extracted. The organic phase was dried and the solvent was removed to obtain the intermediate.

[0048] The intermediate was dissolved in deionized water, and lithium bis(trifluoromethanesulfonyl)imide salt was added. The mixture was stirred at room temperature and centrifuged to obtain a room temperature ionic liquid for gold separation.

[0049] The phase transfer agent is tetrabutylammonium bromide;

[0050] The functional reagent is either bromooctane or 2-ethylhexyl bromide.

[0051] In some embodiments of the present invention, the organic solvent is acetonitrile.

[0052] In some embodiments of the present invention, the molar ratio of tetramethylguanidine, potassium carbonate and functional reagent is 1:3-5:1-1.5; the molar ratio of tetramethylguanidine and phase transfer agent is 3-5:1.

[0053] In some embodiments of the present invention, the protective atmosphere includes, but is not limited to, nitrogen or helium.

[0054] In some embodiments of the present invention, the heating reaction is carried out at a temperature of 60-70°C for one day.

[0055] In some embodiments of the present invention, after the heating reaction is completed, the mixture is filtered and deionized water is added to the filtrate. Petroleum ether can be used to extract the filtrate multiple times to remove excess raw materials and impurities. Saturated sodium bromide is added to the aqueous phase, and dichloromethane can be used for extraction. After extraction, anhydrous magnesium sulfate can be used to dry the organic phase, and rotary evaporation can be used to remove the solvent to obtain the intermediate.

[0056] In some embodiments of the present invention, an excess of lithium bis(trifluoromethanesulfonyl)imide is added, with a molar ratio of lithium bis(trifluoromethanesulfonyl)imide to tetramethylguanidine of 1.1-1.2:1, i.e., an excess of 10%-20% molar percentage. Maintaining this ratio is beneficial for improving the gold extraction efficiency and increasing the gold recovery rate. If the ratio is too low or too high, the gold extraction efficiency will be reduced.

[0057] In some embodiments of the present invention, the stirring time at room temperature is 1.5-2.5 hours, and the product is obtained by centrifugation after stirring. The rotation speed for ion separation can be selected as 10,000-15,000 rpm.

[0058] A third aspect of the present invention provides the application of the above-described room temperature ionic liquid or the room temperature ionic liquid prepared by the above-described preparation method in the extraction of gold (III).

[0059] A fourth aspect of the present invention provides a method for extracting gold (III), comprising the following steps:

[0060] The room-temperature ionic liquid described above or the room-temperature ionic liquid prepared by the above method is mixed with a gold (III)-containing aqueous phase, and after extraction equilibrium, the two phases are separated by centrifugation.

[0061] In some embodiments of the present invention, in order to improve the extraction effect, the room temperature ionic liquid is mixed with the gold (III)-containing aqueous phase and then placed in a constant temperature oscillator to react fully until extraction equilibrium is reached.

[0062] In some embodiments of the present invention, the gold-containing aqueous phase is obtained by adding concentrated hydrochloric acid to a gold (III)-containing mother liquor and diluting it with deionized water.

[0063] In some embodiments of the present invention, the concentration of hydrochloric acid in the gold (III) aqueous phase is 0.1-5 mol / L.

[0064] In some embodiments of the present invention, the concentration of gold in the gold (III) aqueous phase is 980-990 mg / L, and the ratio of the room temperature ionic liquid to the gold (III) aqueous phase is 1-50:1, mg / mL.

[0065] In some embodiments of the present invention, the extraction temperature is 25℃-65℃ and the extraction time is 1-60min.

[0066] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0067] Unless otherwise specified, the experimental methods described in the following examples are conventional methods.

[0068] The aqueous stock solution used in the following examples is a hydrochloric acid solution containing gold or a mixture of gold and other metal ions.

[0069] After the extraction and separation process, the concentration of residual metals in the aqueous phase was determined by ICP-OES, and the extraction rate was calculated using the following formula:

[0070]

[0071] Among them, C in and C eq (mol / L) represents the concentration of metal ions in the aqueous phase before and after extraction.

[0072] Unless otherwise stated, all reagents and materials required for the following examples are commercially available.

[0073] Example 1

[0074] 1. Synthesis of [DIOTMG][NTf2]

[0075] In a 100 mL round-bottom flask, 10 mmol of 1,1,3,3-tetramethylguanidine, 30 mmol of potassium carbonate, 0.2 mmol of tetrabutylammonium bromide, and 22 mmol of 1-bromooctane were added to 30 mL of acetonitrile solution. The mixture was stirred and heated at 65 °C for one day. After the reaction was complete, the mixture was filtered, and 50 mL of deionized water was added to the filtrate. The filtrate was extracted with 50 mL of petroleum ether several times to remove excess raw materials and impurities. Saturated sodium bromide was added to the aqueous phase, followed by extraction with dichloromethane. The dichloromethane phase was then dried with anhydrous magnesium sulfate for 3 hours, and the solvent was removed by rotary evaporation to obtain the intermediate. The intermediate was dissolved in deionized water, and lithium bis(trifluoromethanesulfonyl)imide salt (1.1-1.2 times the molar amount of the intermediate) was added. After stirring at room temperature for 2 hours, the mixture was centrifuged to obtain the product, which is the room-temperature ionic liquid [DIOTMG][NTf2].

[0076] 2. The gold extraction process

[0077] Weigh 40 mg of the synthesized [DIOTMG][NTf2] and place it in a plastic tube as the organic phase.

[0078] Take the stock solution prepared with chloroauric acid, add concentrated hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a gold concentration of 5 mmol / L and a hydrochloric acid concentration of 0.1 mol / L.

[0079] 40 mg of [DIOTMG][NTf2] was mixed with 1 mL of aqueous phase and extracted at 298 K for 30 min. To ensure sufficient contact between the aqueous phase and the ionic liquid phase, mechanical shaking was used to enhance mixing. After extraction, the two phases were completely separated by high-speed centrifugation at 12000 rpm for 5 min. The concentration of residual gold in the upper aqueous phase was analyzed, and the gold extraction rate was calculated. The gold extraction efficiency was 99.2%.

[0080] Example 2

[0081] 1. Synthesis of [DIETMG][NTf2]

[0082] In a 100 mL round-bottom flask, 10 mmol of 1,1,3,3-tetramethylguanidine, 30 mmol of potassium carbonate, 0.2 mmol of tetrabutylammonium bromide, and 22 mmol of 2-ethylhexyl bromide were added to 30 mL of acetonitrile solution. The mixture was stirred and heated at 65 °C for one day. After the reaction was complete, the mixture was filtered, and 50 mL of deionized water was added to the filtrate. The filtrate was extracted several times with 50 mL of petroleum ether to remove excess raw materials and impurities. Saturated sodium bromide was added to the aqueous phase, followed by extraction with dichloromethane. The dichloromethane phase was then dried with anhydrous magnesium sulfate for 3 hours, and the solvent was removed by rotary evaporation to obtain the intermediate. The intermediate was dissolved in deionized water, and a molar amount of the intermediate was added...

[0083] The product, namely the room temperature ionic liquid [DIETMG][NTf2], was obtained by centrifugation after stirring at room temperature for 2 hours with 1.1-1.2 times the amount of lithium bis(trifluoromethanesulfonyl)imide.

[0084] 2. The gold extraction process

[0085] Weigh 50 mg of the synthesized [DIETMG][NTf2] and place it in a plastic tube as the organic phase.

[0086] Take the stock solution prepared with chloroauric acid, add concentrated hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a gold concentration of 5 mmol / L and a hydrochloric acid concentration of 0.1 mol / L.

[0087] 50 mg of [DIETMG][NTf2] was mixed with 1 mL of aqueous phase and extracted at 298 K for 30 min. To ensure sufficient contact between the aqueous phase and the ionic liquid phase, mechanical shaking was used to enhance mixing. After extraction, the two phases were completely separated by high-speed centrifugation at 12000 rpm for 5 min. The concentration of residual gold in the upper aqueous phase was analyzed, and the gold extraction rate was calculated. The gold extraction efficiency was 99.6%.

[0088] Example 3

[0089] 1. Synthesis of [DIOTMG][NTf2]

[0090] The specific synthesis method is described in Example 1.

[0091] 2. The gold extraction process

[0092] 10 mg of the synthesized [DIOTMG][NTf2] was weighed and placed in a plastic tube as the ionic liquid phase.

[0093] Take the stock solution prepared with chloroauric acid, add different volumes of concentrated hydrochloric acid and dilute with deionized water to prepare aqueous phases with gold concentration of 5 mmol / L and hydrochloric acid concentrations of 0.1, 1, 2, 3, 4 and 5 mol / L respectively.

[0094] 10 mg of [DIOTMG][NTf2] was mixed with 1 mL of aqueous phase with different hydrochloric acid concentrations and extracted at 298 K for 30 min. Mechanical shaking was used to enhance mixing to ensure sufficient contact between the aqueous and ionic liquid phases. After extraction, the two phases were completely separated by high-speed centrifugation at 12000 rpm for 5 min. The concentration of residual gold in the upper aqueous phase was analyzed. The extraction efficiency of gold under different hydrochloric acid concentrations is shown in Table 1.

[0095] Table 1. Effect of hydrochloric acid concentration on gold extraction by [DIOTMG][NTf2].

[0096]

[0097] Example 4

[0098] 1. Synthesis of [DIETMG][NTf2]

[0099] The specific synthesis method is described in Example 2.

[0100] 2. The gold extraction process

[0101] 10 mg of the synthesized [DIETMG][NTf2] was weighed and placed in a plastic tube as the ionic liquid phase.

[0102] Take the stock solution prepared with chloroauric acid, add different volumes of concentrated hydrochloric acid and dilute with deionized water to prepare aqueous phases with gold concentration of 5 mmol / L and hydrochloric acid concentrations of 0.1, 1, 2, 3, 4 and 5 mol / L respectively.

[0103] 10 mg of [DIETMG][NTf2] was mixed with 1 mL of aqueous phase with different hydrochloric acid concentrations and extracted at 298 K for 30 min. Mechanical shaking was used to enhance mixing to ensure sufficient contact between the aqueous and ionic liquid phases. After extraction, the two phases were completely separated by high-speed centrifugation at 12000 rpm for 5 min. The concentration of residual gold in the upper aqueous phase was analyzed. The extraction efficiency of gold under different hydrochloric acid concentrations is shown in Table 2.

[0104] Table 2. Effect of hydrochloric acid concentration on gold extraction by [DIETMG][NTf2].

[0105]

[0106] Example 5

[0107] 1. Synthesis of [DIOTMG][NTf2]

[0108] The specific synthesis method is described in Example 1.

[0109] 2. The gold extraction process

[0110] 10 mg of the synthesized [DIOTMG][NTf2] was weighed and placed in a plastic tube as the ionic liquid phase.

[0111] Take the stock solution prepared with chloroauric acid, add a certain volume of concentrated hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a gold concentration of 5 mmol / L and a hydrochloric acid concentration of 0.1 mol / L.

[0112] 10 mg of [DIOTMG][NTf2] was mixed with 1 mL of aqueous phase. Extraction was performed at 298, 308, 318, 328, and 338 K for 30 min. Mechanical shaking was used to enhance mixing and ensure sufficient contact between the aqueous and ionic liquid phases. After extraction, the two phases were completely separated by high-speed centrifugation at 12000 rpm for 5 min. The concentration of residual gold in the upper aqueous phase was analyzed. The extraction efficiency of gold at different temperatures is shown in Table 3.

[0113] Table 3. Effect of temperature on gold extraction from [DIOTMG][NTf2]

[0114]

[0115] Example 6

[0116] 1. Synthesis of [DIETMG][NTf2]

[0117] The specific synthesis method is described in Example 2.

[0118] 2. The gold extraction process

[0119] 10 mg of the synthesized [DIETMG][NTf2] was weighed and placed in a plastic tube as the ionic liquid phase.

[0120] Take the stock solution prepared with chloroauric acid, add a certain volume of concentrated hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a gold concentration of 5 mmol / L and a hydrochloric acid concentration of 0.1 mol / L.

[0121] 10 mg of [DIETMG][NTf2] was mixed with 1 mL of aqueous phase. Extraction was performed at 298, 308, 318, 328, and 338 K for 30 min. Mechanical shaking was used to enhance mixing and ensure sufficient contact between the aqueous and ionic liquid phases. After extraction, the two phases were completely separated by high-speed centrifugation at 12000 rpm for 5 min. The concentration of residual gold in the upper aqueous phase was analyzed. The extraction efficiency of gold at different temperatures is shown in Table 4.

[0122] Table 4. Effect of temperature on gold extraction from [DIETMG][NTf2]

[0123]

[0124] Example 7

[0125] 1. Synthesis of [DIETMG][NTf2]

[0126] The specific synthesis method is described in Example 2.

[0127] 2. The gold extraction process

[0128] 10 mg of the synthesized [DIETMG][NTf2] was weighed and placed in a plastic tube as the ionic liquid phase.

[0129] Different volumes of stock solutions prepared with chloroauric acid were taken, a certain volume of concentrated hydrochloric acid was added, and the solutions were diluted with deionized water to prepare aqueous phases with gold concentrations of 5, 9, 12, 18, 21, 28, and 35 mmol / L and hydrochloric acid concentration of 0.1 mol / L.

[0130] 10 mg of [DIETMG][NTf2] was mixed with 1 mL of aqueous phase with different initial gold concentrations. Extraction was performed at 298 K for 30 min. Mechanical shaking was used to enhance mixing to ensure sufficient contact between the aqueous and ionic liquid phases. After extraction, the two phases were completely separated by high-speed centrifugation at 12000 rpm for 5 min. The concentration of residual gold in the upper aqueous phase was analyzed. The extraction efficiency of gold at different initial concentrations is shown in Table 5.

[0131] Table 5. Effect of initial gold concentration on gold extraction by [DIETMG][NTf2].

[0132]

[0133] Example 8

[0134] 1. Synthesis of [DIETMG][NTf2]

[0135] The specific method for synthesizing ionic liquids is described in Example 2.

[0136] 2. Extraction process

[0137] 10 mg of the synthesized [DIETMG][NTf2] was weighed and placed in a plastic tube as the ionic liquid phase.

[0138] Take the stock solution containing gold (III) and other coexisting metals (Mn (II), Al (III), Co (II), Cu (II), Ni (II), Fe (III)), add a certain volume of concentrated hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a concentration of 5 mmol / L for each metal ion and a concentration of 0.1 mol / L for hydrochloric acid.

[0139] 10 mg of [DIETMG][NTf2] was mixed with 1 mL of the aqueous phase containing the mixed metal ions. Extraction was performed at 298 K for 30 min. Mechanical shaking was used to enhance mixing and ensure sufficient contact between the aqueous and ionic liquid phases. After extraction, the two phases were completely separated by high-speed centrifugation at 12000 rpm for 5 min. The concentration of residual metal ions in the upper aqueous phase was analyzed, and the extraction efficiency of each metal ion is shown in Table 6.

[0140] Table 6. Statistical results of extraction rates of various metals by extractants.

[0141]

[0142] As shown in Table 6, the extractant has a high extraction rate for gold (III), while the extraction rates for other metals (Mn (II), Al (III), Co (II), Cu (II), Ni (II), Fe (III)) are all less than 3%. Therefore, the room temperature ionic liquid extraction system provided by this invention has good extraction selectivity for gold.

[0143] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for extracting gold (III), characterized in that, Includes the following steps: A room-temperature ionic liquid was mixed with a gold (III)-containing aqueous phase, and after extraction equilibrium, the two phases were separated by centrifugation. The volume ratio of the room-temperature ionic liquid to the gold (III)-containing aqueous phase was 1-50:1, mg / mL. The concentration of hydrochloric acid in the gold (III)-containing aqueous phase was 0.1-5 mol / L. The extraction temperature was 298-308 K, and the extraction time was 1-60 min. The concentration of gold (III) in the gold (III)-containing aqueous phase was 980-990 mg / L. The preparation method of the room temperature ionic liquid includes the following steps: Tetramethylguanidine, potassium carbonate, phase transfer agent, and functional reagent were dissolved in an organic solvent and heated under a protective atmosphere. After the reaction was completed, the mixture was filtered and deionized water was added to the filtrate. The filtrate was extracted, and saturated sodium bromide was added to the aqueous phase for extraction. The organic phase was dried and the solvent was removed to obtain an intermediate. The intermediate was dissolved in deionized water, and lithium bis(trifluoromethanesulfonyl)imide was added. The mixture was stirred at room temperature and centrifuged to obtain a room temperature ionic liquid for separating gold(III). The phase transfer agent is tetrabutylammonium bromide; The functional reagent is one of bromooctane or 2-ethylhexyl bromide; The molar ratio of tetramethylguanidine to lithium bis(trifluoromethanesulfonyl)imide is 1:1.1-1.2; The room temperature ionic liquid for separating gold (III) has a tetramethylguanidinyl derivative cation and a bis(trifluoromethanesulfonyl)imide anion; The structural formula of the tetramethylguanidinyl derivative cation is as follows: Where R1 and R2 are both n-octyl or both R1 and R2 are 2-ethylhexyl.

2. The method according to claim 1, characterized in that, The organic solvent is acetonitrile.

3. The method according to claim 1, characterized in that, The molar ratio of tetramethylguanidine, potassium carbonate and functional reagent is 1:3-5:1-1.5; the molar ratio of tetramethylguanidine to phase transfer agent is 3-5:

1.

4. The method according to claim 1, characterized in that, The heating reaction is carried out at a temperature of 60-70℃.

Images