A homogeneous extractant for separating platinum ions in aqueous phase, and preparation method and extraction method

Abstract

The present invention relates to the technical field of separation of precious metals, and in particular to a homogeneous extractant for separating platinum ions in aqueous phase, a preparation method and an extraction method. The homogeneous extractant of the present invention is a side-chain functionalized piperazine-based ionic liquid [EA‑Et‑TMEDA‑PIP][Tf2N]2, which has simple synthesis steps, good stability, and low water solubility, thereby avoiding the problem of loss in the aqueous phase during the extraction process, and improving the cyclicity of the system; no additional organic solvent is required, thereby overcoming the problem of environmental pollution during the extraction process; when used as an extractant for platinum ions, by heating a binary mixed system of ionic liquid and water, efficient extraction of platinum ions is achieved when a homogeneous phase is reached, eliminating the resistance effect of the two-phase interface; and selective separation between platinum ions and other metal ions can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of precious metal separation, and in particular to a homogeneous extractant for separating aqueous platinum ions, a preparation method and an extraction method. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] The precious metal platinum has many excellent physical and chemical properties, such as strong thermal stability, excellent electrical conductivity, good ductility, excellent biocompatibility, etc., which makes it widely used in petrochemical, metallurgy, aerospace, precision instruments and other fields. At the same time, it is also closely related to the development of modern high-tech, and has outstanding advantages in the fields of biotechnology, information technology, and new energy materials technology. At present, the sources of platinum mainly include mineral resources and secondary resources. However, the distribution of mineral resources in the world is extremely uneven. Secondary resources involve a wide range of fields, a wide variety, huge output, and high grade purity, which can effectively make up for the problem of insufficient primary resources. Therefore, vigorously promoting the recovery of precious metal platinum from secondary resources is of great significance to the current resource status and the development of the precious metal industry.

[0004] Liquid-liquid extraction is the most commonly used method for recovering various metal resources due to its advantages such as simple operation, low unit energy consumption, high separation efficiency and strong separation selectivity. However, a large amount of toxic, volatile and flammable organic solvents are often used in the traditional liquid-liquid extraction process, thus causing serious environmental pollution problems. Ionic liquids have been widely studied as alternative organic solvents for solvent extraction. However, ionic liquids usually have a high viscosity, and due to the inevitable existence of a two-phase interface between the ionic liquid phase and the aqueous phase, it will slow down the mass transfer and kinetic process. In addition, the actual application environment is relatively complex, and multiple metal ions coexist and have similar properties, making it impossible to separate them from each other, making it difficult to achieve efficient and selective extraction. At the same time, there are also defects such as high water solubility, high extraction loss rate and poor recyclability of ionic liquids, which hinder industrial production. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a homogeneous extractant for separating platinum ions in aqueous phase, a preparation method and an extraction method. The homogeneous extractant of the present invention is an asymmetric piperazine-based ionic liquid [EA-Et-TMEDA-PIP][Tf2N]2, which has simple synthesis steps, good stability, low water solubility, avoids the loss problem in the aqueous phase during the extraction process, and improves the cyclicity of the system; no additional organic solvent is required, which overcomes the problem of environmental pollution during the extraction process; when used as an extractant for platinum ions, by heating the binary mixed system of ionic liquid and water, efficient extraction of platinum ions is achieved when a homogeneous phase is reached, eliminating the resistance effect of the two-phase interface; and can achieve selective separation between platinum ions and other metal ions.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, the present invention provides a homogeneous extractant for separating platinum ions in an aqueous phase, wherein the homogeneous extractant is a side chain functionalized piperazine ionic liquid [EA-Et-TMEDA-PIP][Tf2N]2, and the structure is shown in Formula I:

[0008]

[0009] In a second aspect, the present invention provides a method for preparing a homogeneous extractant for separating aqueous platinum ions as described in the first aspect, comprising the following steps:

[0010] 1-(2-(dimethylamino)ethyl)-4-methylpiperazine and ethyl chloroacetate are mixed in a flask, and heated under reflux to react to obtain an intermediate product; an aqueous solution of lithium bis(trifluoromethylsulfonyl)imide is added to the aqueous solution of the intermediate product, and the reaction is continuously stirred at room temperature to form a two-phase system, and the lower layer of ionic liquid is taken out to wash and remove the reactant, and the homogeneous extraction agent is obtained after washing and vacuum drying.

[0011] In a third aspect, the present invention provides a method for extracting platinum ions, comprising the following steps:

[0012] (1) using the homogeneous extractant for separating platinum ions from the aqueous phase described in the first aspect as an ionic liquid phase;

[0013] (2) taking a mother liquor containing platinum ions, adding hydrochloric acid and diluting it with deionized water to form an aqueous phase;

[0014] (3) heating and mixing the ionic liquid phase and the aqueous phase so that the platinum ions are extracted into the ionic liquid phase;

[0015] (4) Taking the ionic liquid phase, adding a stripping agent to strip the platinum ions, and separating the platinum ions from the ionic liquid phase.

[0016] The beneficial effects achieved by one or more technical solutions of the present invention are as follows:

[0017] The ionic liquid [EA-Et-TMEDA-PIP][Tf2N]2 disclosed in the present invention has simple synthesis steps, good stability and low water solubility, which avoids the loss problem in the aqueous phase during the extraction process and improves the recyclability of the system.

[0018] The homogeneous system extraction process disclosed in the present invention is green, environmentally friendly and sustainable, does not require the addition of additional organic solvents, and overcomes the problem of environmental pollution during the extraction process.

[0019] The extraction and separation method provided by the present invention achieves efficient extraction of platinum ions when a homogeneous phase is achieved by heating a binary mixed system of ionic liquid and water, thereby eliminating the resistance effect of the two-phase interface and accelerating the kinetic process of the system.

[0020] The extractant [EA-Et-TMEDA-PIP][Tf2N]2 has excellent extraction performance and extraction selectivity for platinum ions. The extraction rate of platinum ions in homogeneous extraction can reach more than 95%, while the extraction rate for other metal ions is less than 3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] Figure 1 is the H NMR spectrum of [EA-Et-TMEDA-PIP][Tf2N]2 in Example 1 of the present invention, where f1 represents the chemical shift;

[0023] Figure 2 The figure is a comparison between homogeneous extraction and traditional liquid-liquid extraction in Example 9 of the present invention. DETAILED DESCRIPTION

[0024] The first typical embodiment of the present invention is a homogeneous extractant for separating platinum ions in aqueous phase, wherein the homogeneous extractant is a side chain functionalized piperazine-based ionic liquid [EA-Et-TMEDA-PIP][Tf2N]2, and the structure is shown in Formula I:

[0025]

[0026] The oxygen-containing functional groups of the cationic side chains in the side-chain functionalized piperazine ionic liquid of the present application are easy to interact with water by hydrogen bonds, so that the extraction system can gradually merge into one phase with water when heated; and the anionic bis(trifluoromethylsulfonyl)imide provides a hydrophobic effect, so that the extraction system is easy to separate from water when it returns to room temperature, thereby realizing the extraction process of "homogeneous extraction and heterogeneous separation".

[0027] A second typical embodiment of the present invention is a method for preparing a homogeneous extractant for separating platinum ions in an aqueous phase as described in the first typical embodiment, comprising the following steps:

[0028] 1-(2-(dimethylamino)ethyl)-4-methylpiperazine and ethyl chloroacetate are mixed in a flask, and acetonitrile is added as a solvent to heat and reflux to obtain an intermediate product; an aqueous solution of lithium bis(trifluoromethylsulfonyl)imide is added to the aqueous solution of the intermediate product, and the reaction is continuously stirred at room temperature to form a two-phase system, and the lower layer of ionic liquid is taken out for washing to remove the reactant, and the homogeneous extraction agent is obtained after washing and vacuum drying.

[0029] In one or more examples of this embodiment, the molar ratio of 1-(2-(dimethylamino)ethyl)-4-methylpiperazine to ethyl chloroacetate is 1:1-3.

[0030] In one or more examples of this embodiment, the heating reflux temperature is 85° C. and the time is 12-24 hours.

[0031] In one or more examples of this embodiment, the molar ratio of the intermediate product to lithium bis(trifluoromethylsulfonyl)imide is 1:1-3.

[0032] In one or more examples of this embodiment, the stirring time at room temperature is 12-24 hours.

[0033] In one or more embodiments of this embodiment, the washing is performed by washing with deionized water until no Cl is detected. - until.

[0034] In one or more examples of this embodiment, the vacuum drying temperature is 50-70° C. and the time is 24-48 hours.

[0035] In a third typical embodiment of the present invention, a method for extracting platinum ions comprises the following steps:

[0036] (1) using the homogeneous extractant for separating platinum ions from the aqueous phase described in the first exemplary embodiment as an ionic liquid phase;

[0037] (2) taking a mother liquor containing platinum ions, adding hydrochloric acid and diluting it with deionized water to form an aqueous phase;

[0038] (3) heating and mixing the ionic liquid phase and the aqueous phase so that the platinum ions are extracted into the ionic liquid phase;

[0039] (4) Taking the ionic liquid phase, adding a stripping agent to strip the platinum ions, and separating the platinum ions from the ionic liquid phase.

[0040] In one or more examples of this embodiment, in step (2), the concentration of platinum ions in the aqueous phase is 4-6 mmol / L, and the concentration of hydrochloric acid in the aqueous phase is 0.1-3 mmol / L.

[0041] In one or more examples of this embodiment, in step (3), the mass ratio of the ionic liquid phase to the aqueous phase is 1:20-100.

[0042] In one or more examples of this embodiment, the heating temperature is 10-90° C. and the heating time is 1-60 min.

[0043] In one or more examples of this embodiment, the mother liquor further contains metal ions, and the metal is one or more of Ir, Cu, Al, Sn, Zn, Ce, Fe, and Ni.

[0044] In one or more examples of this embodiment, the stripping agent in step (4) is one or more of H2C2O4, CS(NH2)2, and Na2S2O3.

[0045] After the extraction and separation process is completed, the metal ion concentration in the extract is measured by ICP-OES (inductively coupled plasma emission spectrometer), and the calculation formula of the extraction rate used is as follows:

[0046]

[0047] Among them, C in and C eq (mol / L) represents the concentration of platinum ions in the aqueous phase before and after extraction, respectively.

[0048] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in combination with specific embodiments and comparative examples.

[0049] Example 1

[0050] 1-(2-(dimethylamino)ethyl)-4-methylpiperazine and ethyl chloroacetate were mixed in a flask at a molar ratio of 1:1, and acetonitrile was added as a solvent and heated to reflux for 24 hours. After the reaction was completed, it was cooled and restored to room temperature. The product was washed with ether to remove the residual raw materials to obtain the intermediate product [EA-Et-TMEDA-PIP][Cl]2. Then, an aqueous solution of lithium bis(trifluoromethylsulfonyl)imide was added to the aqueous solution of the intermediate product [EA-Et-TMEDA-PIP][Cl]2, and the molar ratio of lithium bis(trifluoromethylsulfonyl)imide and [EA-Et-TMEDA-PIP][Cl]2 was 1:1. The reaction was stirred continuously at room temperature for 24 hours until a two-phase system was formed. The lower ionic liquid phase was taken and washed with water to remove the unreacted intermediate product [EA-Et-TMEDA-PIP][Cl]2 and lithium bis(trifluoromethylsulfonyl)imide until Cl could not be detected. - Finally, the mixture was dried in a vacuum oven at 50°C for 24 hours to obtain a homogeneous extractant [EA-Et-TMEDA-PIP][Tf2N]2. The H NMR spectrum of [EA-Et-TMEDA-PIP][Tf2N]2 is shown in Figure 1 As shown, H NMR spectrum verified the successful synthesis of [EA-Et-TMEDA-PIP][Tf2N]2.

[0051] Example 2

[0052] 1-(2-(dimethylamino)ethyl)-4-methylpiperazine and ethyl chloroacetate were mixed in a flask at a molar ratio of 1:2, and acetonitrile was added as a solvent and heated to reflux for 20 hours. After the reaction was completed, it was cooled and restored to room temperature. The product was washed with ether to remove the residual raw materials to obtain the intermediate product [EA-Et-TMEDA-PIP][Cl]2. Then, an aqueous solution of lithium bis(trifluoromethylsulfonyl)imide was added to the aqueous solution of the intermediate product [EA-Et-TMEDA-PIP][Cl]2, and the molar ratio of lithium bis(trifluoromethylsulfonyl)imide and [EA-Et-TMEDA-PIP][Cl]2 was 1:2. The reaction was stirred continuously at room temperature for 20 hours until a two-phase system was formed. The lower ionic liquid phase was taken and washed with water to remove the unreacted intermediate product [EA-Et-TMEDA-PIP][Cl]2 and lithium bis(trifluoromethylsulfonyl)imide until Cl could not be detected. - Finally, the mixture was dried in a vacuum oven at 60°C for 36 hours to obtain a homogeneous extractant [EA-Et-TMEDA-PIP][Tf2N]2.

[0053] Example 3

[0054] 1-(2-(dimethylamino)ethyl)-4-methylpiperazine and ethyl chloroacetate were mixed in a flask at a molar ratio of 1:3, and acetonitrile was added as a solvent and heated to reflux for 18 hours. After the reaction was completed, it was cooled and restored to room temperature. The product was washed with ether to remove the residual raw materials to obtain the intermediate product [EA-Et-TMEDA-PIP][Cl]2. Then, an aqueous solution of lithium bis(trifluoromethylsulfonyl)imide was added to the aqueous solution of the intermediate product [EA-Et-TMEDA-PIP][Cl]2, and the molar ratio of lithium bis(trifluoromethylsulfonyl)imide and [EA-Et-TMEDA-PIP][Cl]2 was 1:3. The reaction was stirred continuously at room temperature for 18 hours until a two-phase system was formed. The lower ionic liquid phase was taken and washed with water to remove the unreacted intermediate product [EA-Et-TMEDA-PIP][Cl]2 and lithium bis(trifluoromethylsulfonyl)imide until Cl could not be detected. - Finally, it was dried in a vacuum oven at 70°C for 40 hours to obtain a homogeneous extractant [EA-Et-TMEDA-PIP][Tf2N]2.

[0055] Example 4

[0056] Preparation of ionic liquid phase: Weigh 30 mg of the homogeneous extractant synthesized in Example 1 as the ionic liquid phase.

[0057] Prepare the aqueous phase: take the mother liquor containing platinum ions, add hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a platinum ion concentration of 5 mmol / L and a hydrochloric acid concentration of 0.1 mol / L.

[0058] The mass ratio of the ionic liquid phase to the aqueous phase is 1:30. The temperature is raised to 70°C to form a homogeneous solution, so that the aqueous phase and the ionic liquid phase are fully in contact. After heating for 1-60 minutes, the solution is cooled to room temperature to separate the phases. The aqueous phase solution is taken to determine the content of platinum ions and calculate the extraction rate.

[0059] In the above extraction and separation process, when the extraction equilibrium time is 1min, 5min, 10min, 15min, 30min and 60min, the extraction rates of platinum ions are 65.9%, 79.7%, 89.6%, 97.6%, 97.6% and 97.6% respectively.

[0060] Example 5

[0061] Preparation of ionic liquid phase: Weigh 30 mg of the homogeneous extractant synthesized in Example 1 as the ionic liquid phase.

[0062] Prepare the aqueous phase: take the mother liquor containing platinum ions, add hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a platinum ion concentration of 5 mmol / L and a hydrochloric acid concentration of 0.1 mol / L.

[0063] The masses of the ionic liquid phases were 10 mg, 15 mg, 20 mg, 30 mg, 40 mg, and 50 mg, respectively, and the aqueous phase was 1.0 g. The temperature was raised to 70°C to form a homogeneous solution, so that the aqueous phase and the ionic liquid phase were fully in contact. After heating for 30 minutes, the solution was cooled to room temperature to separate the phases. The aqueous phase solution was taken to determine the platinum ion content and the extraction rate was calculated, as shown in Table 1.

[0064] Table 1 Effect of different amounts of homogeneous extractant [EA-Et-TMEDA-PIP][Tf2N]2 on the extraction rate of platinum ions

[0065]

[0066] Example 6

[0067] Preparation of ionic liquid phase: Weigh 30 mg of the homogeneous extractant synthesized in Example 1 as the ionic liquid phase.

[0068] Prepare the aqueous phase: take the mother liquor containing platinum ions, add hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a platinum ion concentration of 5 mmol / L and a hydrochloric acid concentration of 0.1 mol / L.

[0069] The mass ratio of the ionic liquid phase to the aqueous phase was 1:30. The temperature was raised to 10-80°C to form a homogeneous solution, so that the aqueous phase and the ionic liquid phase were fully in contact. After heating for 30 minutes, the solution was cooled to room temperature to separate the phases. The aqueous phase solution was taken to determine the content of platinum ions and calculate the extraction rate. The results are shown in Table 2.

[0070] Table 2 Extraction rate of platinum ions by [EA-Et-TMEDA-PIP][Tf2N]2 at different extraction temperatures

[0071] Temperature(℃) 10 20 30 40 50 60 70 80 Extraction rate (%) 42.7 50.3 58.7 66.9 78.7 88.9 97.6 97.6

[0072] Example 7

[0073] Preparation of ionic liquid phase: Weigh 30 mg of the homogeneous extractant synthesized in Example 1 as the ionic liquid phase.

[0074] Prepare the aqueous phase: take the mother liquor containing platinum ions, add hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a platinum ion concentration of 5mmol / L and a hydrochloric acid concentration of 0.1-3mol / L.

[0075] The mass ratio of the ionic liquid phase to the aqueous phase was 1:30. The temperature was raised to 70°C to form a homogeneous solution, so that the aqueous phase and the ionic liquid phase were fully in contact. After heating for 30 minutes, the solution was cooled to room temperature to separate the phases. The aqueous phase solution was taken to determine the content of platinum ions and the extraction rate was calculated, as shown in Table 3.

[0076] Table 3 Extraction rate of platinum ions by [EA-Et-TMEDA-PIP][Tf2N]2 at different hydrochloric acid concentrations

[0077] Hydrochloric acid concentration (mol / L) 0.1 0.5 1.0 1.5 2.0 3.0 Extraction rate (%) 97.6 84.5 66.1 50.0 41.5 27.4

[0078] Example 8

[0079] Preparation of ionic liquid phase: Weigh 30 mg of the homogeneous extractant synthesized in Example 1 as the ionic liquid phase.

[0080] Prepare the aqueous phase: take the mother liquor containing platinum ions, add hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a platinum ion concentration of 5mmol / L. Use hydrochloric acid to fix the hydrogen ion concentration in the aqueous phase to 0.1mol / L, and add different masses of sodium chloride to change the chloride ion concentration between 0.1-3mol / L.

[0081] The mass ratio of the ionic liquid phase to the aqueous phase was 1:30. The temperature was raised to 70°C to form a homogeneous solution, so that the aqueous phase and the ionic liquid phase were fully in contact. After heating for 30 minutes, the solution was cooled to room temperature to separate the phases. The aqueous phase solution was taken to determine the content of platinum ions and calculate the extraction rate, as shown in Table 4. Chloride ions and chloroplatinate anions and [EA-Et-TMEDA-PIP] + The competitive effect of cation binding makes the increase in chloride ion concentration difficult for the extraction reaction to proceed forward.

[0082] Table 4 Extraction rate of platinum ions by [EA-Et-TMEDA-PIP][Tf2N]2 at different chloride ion concentrations

[0083]

[0084]

[0085] Example 9

[0086] Preparation of ionic liquid phase: Weigh 30 mg of the homogeneous extractant synthesized in Example 1 as the ionic liquid phase.

[0087] Prepare the aqueous phase: take the mother liquor containing platinum ions, add hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a platinum ion concentration of 5 mmol / L and a hydrochloric acid concentration of 0.1 mol / L.

[0088] Homogeneous extraction: The mass ratio of the ionic liquid phase to the aqueous phase is 1:30. The temperature is raised to 70°C to form a homogeneous solution so that the aqueous phase and the ionic liquid phase are fully in contact. After heating for 1-60 minutes, the solution is cooled to room temperature to separate the phases. The aqueous phase solution is taken to determine the content of platinum ions and calculate the extraction rate.

[0089] Traditional liquid-liquid extraction system: The ionic liquid is dissolved in chloroform, dichloromethane, and ethyl acetate respectively, then contacted with the aqueous phase and shaken for 1-60 minutes, and the aqueous phase solution is taken to determine the platinum ion content and calculate the extraction rate.

[0090] In the above extraction process, the comparison between the homogeneous extraction system and the traditional liquid-liquid extraction system (adding chloroform / dichloromethane / ethyl acetate) is as follows: Figure 2 As shown. Figure 2 It can be seen that the homogeneous system extraction process is more environmentally friendly and does not require the addition of additional organic solvents, thus overcoming the problem of environmental pollution during the extraction process. At the same time, by heating the binary mixed system of ionic liquid and water, efficient extraction of platinum ions is achieved when a homogeneous phase is reached, eliminating the resistance effect of the two-phase interface and accelerating the mass transfer rate and extraction kinetics of the system.

[0091] Example 10

[0092] Preparation of ionic liquid phase: Weigh 30 mg of the homogeneous extractant synthesized in Example 1 as the ionic liquid phase.

[0093] Prepare the aqueous phase: dissolve various metal ions in 0.1 mol / L HCl solution, fix the concentration of each metal solution to 5 mmol / L, and obtain a multi-metal solution; in addition to platinum ions, the system also contains ions of Ir, Cu, Al, Sn, Zn, Ce, Fe, and Ni.

[0094] The mass ratio of the ionic liquid phase to the aqueous phase was 1:30. The temperature was raised to 70°C to form a homogeneous solution, so that the aqueous phase and the ionic liquid phase were fully in contact. After heating for 30 minutes, the solution was cooled to room temperature to separate the phases. The aqueous phase solution was taken to determine the content of metal ions and the extraction rate was calculated. The extraction rates of various metal ions are shown in Table 5.

[0095] Table 5 Extraction rate of various metal ions by [EA-Et-TMEDA-PIP][Tf2N]2

[0096] Metal ions Pt Ir Cu Al Sn Zn Ce Fe Ni Extraction rate % 97.6 1.02 0.85 0.56 1.13 0.77 0.34 0.95 1.23

[0097] [EA-Et-TMEDA-PIP][Tf2N]2 has excellent extraction effect on platinum ions. In the case of interference from many metal ions, platinum ions can still be selectively extracted, while the extraction rates of other metals remain at a low level. Therefore, the homogeneous system constructed by [EA-Et-TMEDA-PIP][Tf2N]2 ionic liquid has excellent extraction ability for platinum ions.

[0098] Embodiment 11

[0099] Preparation of ionic liquid phase: Weigh 30 mg of the homogeneous extractant synthesized in Example 1 as the ionic liquid phase.

[0100] Prepare the aqueous phase: take the mother liquor containing platinum ions, add hydrochloric acid and dilute with deionized water to prepare an aqueous phase with a platinum ion concentration of 5 mmol / L and a hydrochloric acid concentration of 0.1 mol / L.

[0101] The mass ratio of the ionic liquid phase to the aqueous phase was 1:30, and the temperature was raised to 70°C to form a homogeneous solution, so that the aqueous phase and the ionic liquid phase were fully in contact, and then cooled to room temperature after heating for 15 minutes to separate the phases, and the aqueous phase was removed. 1 mol / L stripping agent was mixed with the ionic liquid loaded with platinum ions for 30 minutes, and the upper stripping solution was taken to determine the stripping rate of platinum ions. The effects of different stripping agents on the stripping rate of platinum ions are shown in Table 6.

[0102] Table 6 Effect of different stripping agents on the stripping rate of platinum ions

[0103]

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A homogeneous extractant for separating platinum ions in aqueous phase, characterized in that: The homogeneous extractant is a side chain functionalized piperazine-based ionic liquid [EA-Et-TMEDA-PIP][Tf2N]2, the structure of which is shown in Formula I: Formula I.

2. A method for preparing a homogeneous extractant for separating platinum ions in aqueous phase as claimed in claim 1, characterized in that: The following steps are involved: 1-(2-(dimethylamino)ethyl)-4-methylpiperazine and ethyl chloroacetate are mixed in a flask, and acetonitrile is added as a solvent to heat and reflux to obtain an intermediate product; an aqueous solution of lithium bis(trifluoromethylsulfonyl)imide is added to the aqueous solution of the intermediate product, and the reaction is continuously stirred at room temperature to form a two-phase system, and the lower layer of ionic liquid is taken out for washing to remove the reactant, and the homogeneous extraction agent is obtained after washing and vacuum drying.

3. The preparation method according to claim 2, characterized in that: The molar ratio of 1-(2-(dimethylamino)ethyl)-4-methylpiperazine to ethyl chloroacetate is 1:1-3; The heating reflux temperature is 85° C. and the time is 12-24 h.

4. The preparation method according to claim 2, characterized in that: The molar ratio of the intermediate product to lithium bis(trifluoromethylsulfonyl)imide is 1:1-3; The stirring time at room temperature is 12-24 h.

5. The preparation method according to claim 2, characterized in that: The washing is performed by washing with deionized water until no Cl is detected. - until; The vacuum drying temperature is 50-70°C and the time is 24-48 hours.

6. A method for extracting platinum ions, characterized in that: The following steps are involved: (1) using the homogeneous extractant for separating platinum ions from an aqueous phase as claimed in claim 1 as an ionic liquid phase; (2) taking a mother liquor containing platinum ions, adding hydrochloric acid and diluting it with deionized water to form an aqueous phase; (3) heating and mixing the ionic liquid phase and the aqueous phase so that the platinum ions are extracted into the ionic liquid phase; (4) Taking the ionic liquid phase, adding a stripping agent to strip the platinum ions, and separating the platinum ions from the ionic liquid phase; the stripping agent is one or more of H2C2O4, CS(NH2)2, and Na2S2O3.

7. The extraction method according to claim 6, characterized in that In step (2), the platinum ion concentration in the aqueous phase is 4-6 mmol / L, and the hydrochloric acid concentration in the aqueous phase is 0.1-3 mmol / L.

8. The extraction method according to claim 6, characterized in that In step (3), the mass ratio of the ionic liquid phase to the aqueous phase is 1:20-100; In step (3), the heating temperature is 10-90°C and the heating time is 1-60 min.

9. The extraction method according to claim 6, characterized in that The mother liquor also contains other metal ions, and the metal is one or more of Ir, Cu, Al, Sn, Zn, Ce, Fe, and Ni.

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