Extractant and method for purifying copper-containing cyanide wastewater

Abstract

The present application provides an extractant and a method for purifying copper-containing cyanide wastewater, belonging to the technical field of wastewater purification. The extractant uses an imidazole ring as the molecular backbone, and through a quaternization reaction, aliphatic chain functional groups are introduced to adjust the hydrophobic property of the extractant, ensuring that the extractant is insoluble in the inorganic aqueous phase. By derivatizing the amino group to form a thioester group, the terminal mercapto group hydrolyzes under alkaline conditions to form an S- activation site, which can effectively bond with cuprous ions (Ⅰ). At the same time, the S- activation site and the lone pair electrons on the adjacent N atom cooperate with each other to chelate cuprous ions (Ⅰ) to the greatest extent, ensuring that the cuprous ions exist in the form of chelates and will not be further converted into the free state. In addition, the lone pair electrons on the N atom and the carboxyl group can cooperate with each other to achieve targeted chelation of cupric ions (Ⅱ) in the solution. The present application realizes the efficient extraction of copper in the cyanide-containing wastewater, achieving the purpose of purifying the copper-containing cyanide wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater purification, and particularly relates to an extractant and a method for purifying copper-containing cyanide wastewater by using the same. Background Art

[0002] Copper-containing wastewater generated in industries such as chemical industry / paint and electroplating often exists in the form of cyanide complexes. The copper element in the copper-containing cyanide wastewater shows different valence states, such as [Cu(CN)2] - , [Cu(CN)3] 2- , [Cu(CN)4] 3- . The copper plating rinse wastewater contains 300 - 450 mg / L of free cyanide ions and 400 - 550 mg / L of [Cu(CN)2] - or [Cu(CN)4] 3- .

[0003] In the prior art, the treatment measures for copper-containing cyanide wastewater mainly include acidification aeration alkali liquor neutralization method, chlorination method, electrolytic oxidation method, ferrous sulfate complexation method, air stripping method, etc. Among them, the alkali chlorination method is prone to cause secondary pollution, the purification degree of the ferrous sulfate complexation method is incomplete, the electrolytic oxidation method has high energy consumption, and the air stripping method pollutes the atmosphere. Compared with the above methods, the extraction process is not easy to cause secondary pollution and has a high purification degree, showing obvious advantages.

[0004] The extraction capacity is defined as the maximum capacity for retaining the target ions. If the total amount of the target ions exceeds the capacity of the extractant, it will lead to incomplete extraction of the target ions, remaining in the inorganic phase, and ultimately affecting the purification effect of the target ions. Since the content in the copper-containing cyanide waste liquid is large and the extraction capacity of the existing extractants is limited, it is difficult to achieve efficient extraction of copper. In order to meet the national discharge standards for the effluent, a large amount of extractant is required.

[0005] In view of this, it is necessary to design an improved extractant and a method for purifying copper-containing cyanide wastewater to solve the above problems. Summary of the Invention

[0006] In view of the technical problems existing in the background art, the present application provides an extractant and a method for purifying copper-containing cyanide wastewater by using the same. The extractant uses an imidazole ring as the molecular skeleton, and through a quaternization reaction, an aliphatic chain functional group is introduced to adjust the hydrophobic property of the extractant, ensuring that the extractant is insoluble in the inorganic aqueous phase. By derivatizing the amino group, a thioester group is formed, and the terminal mercapto group hydrolyzes under alkaline conditions to form S - activation sites, which can effectively bond with copper ions (Ⅰ). At the same time, S -The activation site and the lone pair electrons on the adjacent N atom cooperate with each other to maximize the chelation of cuprous ions (I), ensuring that the cuprous ions exist in the form of chelates and will not be further converted into the free state. In addition, the lone pair electrons on the N atom and the carboxyl group can cooperate with each other to achieve the targeted chelation of cupric ions (II) in the solution. At the same time, the steric effect of the thioester group results in the final chelation product existing in the trans form, and this spatial orientation greatly improves the stability of the copper chelate, which is beneficial to the conversion of cupric ions (II) from the inorganic interface to the organic interface during the extraction process.

[0007] That is, through the design of the extractant molecular skeleton, the types of functional group derivatization, and the regulation of steric hindrance, the present application ensures the efficient chelation of the activation site of the extractant molecule with cupric ions of different valence states, realizes the efficient extraction of copper in cyanide-containing wastewater, and achieves the purpose of purifying copper-containing cyanide wastewater.

[0008] In the first aspect, the present application provides an extractant, and the structural formula of the extractant is as follows:

[0009] 。

[0010] In the second aspect, the present application provides a method for purifying copper-containing cyanide wastewater with an extractant. The extraction is carried out using the aforementioned extractant, and the method includes the following steps:

[0011] S1, mixing and dissolving the extractant with a diluent to obtain an extractant diluent;

[0012] S2, adding the extractant diluent to the copper-containing cyanide alkaline solution to achieve the selective extraction of copper in the cyanide solution.

[0013] Further, the pH range of the copper-containing cyanide alkaline solution is 9 - 11.

[0014] Further, the diluent is sulfonated kerosene.

[0015] Further, copper exists in the form of [Cu(CN)2] - , [Cu(CN)3] 2- , [Cu(CN)4] 3- in the solution.

[0016] Further, in the extractant diluent, the volume ratio of the extractant to the diluent is 1:(10 - 100).

[0017] Further, the concentration range of free cyanide in the copper-containing cyanide alkaline solution is 100 mg / L - 1000 mg / L, and the concentration range of total cyanide is 100 mg / L - 2000 mg / L.

[0018] Further, the cyanide-containing copper wastewater is one or more of the copper-containing cyanide waste liquid remaining after the activated carbon adsorption of the cyanide gold extraction solution, the copper-containing cyanide waste liquid remaining after the ion exchange resin adsorption of the cyanide gold extraction solution, the copper-containing cyanide electroplating waste liquid, and the copper plating rinsing wastewater.

[0019] Further, the volume ratio of the diluent of the extractant to the cyanide alkaline solution containing copper is 1:(1 - 10).

[0020] The beneficial effects of this application are as follows:

[0021] 1) This application provides an extractant. This extractant uses an imidazole ring as the molecular backbone. Through quaternization reaction, aliphatic chain functional groups are introduced to adjust the hydrophobic property of the extractant, ensuring that the extractant is insoluble in the inorganic aqueous phase. By derivatizing the amino group to form a thioester group, the terminal mercapto group hydrolyzes under alkaline conditions to form an S - activation site, which can effectively bond with cuprous ions (Ⅰ). At the same time, the S - activation site and the lone pair electrons on the adjacent N atom cooperate with each other to chelate cuprous ions (Ⅰ) to the greatest extent, ensuring that the cuprous ions exist in the form of chelates and will not be further converted into the free state. Moreover, the lone pair electrons on the N atom and the carboxyl group can cooperate with each other to achieve targeted chelation of cupric ions (Ⅱ) in the solution. At the same time, the steric effect of the thioester group results in the final chelation product existing in the trans form, and this spatial orientation greatly improves the stability of the copper chelate, which is beneficial to the transformation of cupric ions (Ⅱ) from the inorganic interface to the organic interface during the extraction process.

[0022] 2) By designing the molecular backbone of the extractant, the types of functional group derivatization, and the regulation of steric hindrance, this application ensures the efficient chelation of the activation sites of the extractant molecules with cuprous ions of different valences, realizes the efficient extraction of copper in the cyanide-containing wastewater, and achieves the purpose of purifying the cyanide-containing copper wastewater.

[0023] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of this application more obvious and understandable, the following specifically gives the specific implementation manners of this application. Description of the Drawings

[0024] In order to more clearly illustrate the technical solution of this application, the drawings used in this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is the synthesis route diagram of the extractant provided by this application.

[0026] Figure 2 The physical diagram of the extractant provided for this application.

[0027] Figure 3 The 1H NMR spectrum of the extractant provided for this application; wherein, (a) is the full 1H NMR spectrum, and (b) is the enlarged spectrum in the range of chemical shift 0.5 - 4 ppm of the 1H NMR spectrum.

[0028] Figure 4 The mechanism diagram of the interaction between the extractant provided for this application and copper ions. Detailed implementation manners

[0029] Next, the embodiments of the technical solution of this application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of this application more clearly, so they are only examples and cannot be used to limit the protection scope of this application.

[0030] In the first aspect, an embodiment of this application provides an extractant, and the structural formula of the extractant is as follows:

[0031] .

[0032] In the second aspect, this application provides a method for purifying copper-containing cyanide wastewater with an extractant. The extraction is carried out using the aforementioned extractant, and the method includes the following steps:

[0033] S1. Mix and dissolve the extractant with a diluent to obtain a diluted extractant solution;

[0034] Among them, the diluent is sulfonated kerosene. In the diluted extractant solution, the volume ratio of the extractant to the diluent is 1:(10 - 100).

[0035] S2. Add the diluted extractant solution to the copper-containing cyanide alkaline solution to achieve selective extraction of copper in the cyanide solution.

[0036] Among them, in step S2, sodium hydroxide is used to adjust the pH range of the copper-containing cyanide alkaline solution to 9 - 11.

[0037] Copper exists in the solution in the form of [Cu(CN)2] - , [Cu(CN)3] 2- , [Cu(CN)4] 3- .

[0038] The concentration range of free cyanide in the copper-containing cyanide alkaline solution is 100 mg / L - 1000 mg / L, and the concentration range of total cyanide is 100 mg / L - 2000 mg / L.

[0039] The volume ratio of the diluent of the extractant to the copper-containing alkaline cyanide solution is 1:(1 - 10).

[0040] In the technical solution of the embodiment of the present application, the extractant takes the imidazole ring as the molecular backbone. Through the quaternization reaction, aliphatic chain functional groups are introduced to adjust the hydrophobic property of the extractant, ensuring that the extractant is insoluble in the inorganic aqueous phase. By derivatizing the amino group, a thioester group is formed, and the terminal mercapto group hydrolyzes under alkaline conditions to form S - activation sites, which can effectively bond with cuprous ions (Ⅰ). At the same time, S - The activation sites and the lone pair electrons on the adjacent N atoms cooperate with each other to chelate cuprous ions (Ⅰ) to the greatest extent, ensuring that the cuprous ions exist in the form of chelates and will not be further converted into the free state. Moreover, the lone pair electrons on the N atom and the carboxyl group can cooperate with each other to achieve the targeted chelation of cupric ions (Ⅱ) in the solution. At the same time, the steric effect of the thioester group causes the final chelation product to exist in the trans form, and this spatial orientation greatly improves the stability of the copper chelate, which is beneficial to the conversion of cupric ions (Ⅱ) from the inorganic interface to the organic interface during the extraction process, realizing the efficient extraction of copper in the cyanide-containing wastewater and achieving the purpose of purifying the copper-containing cyanide wastewater.

[0041] In the technical solution of the embodiment of the present application, by using a specific extractant, copper in the solution is selectively extracted. After the extraction is completed, the organic phase is separated, and the concentration of copper in the inorganic liquid phase solution is detected and the extraction rate is calculated. This method can selectively extract copper in the solution, reduce the interference of other impurities, and improve the purity of copper. By recovering valuable metals from the wastewater, environmental pollution is reduced, which is beneficial to achieving sustainable development. This method has simple steps and is easy to operate, which is beneficial to popularization and application in actual production.

[0042] The copper-containing cyanide wastewater is one or more of the copper-containing cyanide waste liquid remaining after the activated carbon adsorption of the cyanide gold extraction solution, the copper-containing cyanide waste liquid remaining after the ion exchange resin adsorption of the cyanide gold extraction solution, the copper-containing cyanide electroplating waste liquid, and the copper plating rinse wastewater.

[0043] In the technical solution of the embodiment of the present application, the extractant can effectively extract copper from different types of wastewater, while ensuring the environmental protection, safety and economic benefits of the process.

[0044] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application and should not be construed as a limitation of the present application. For those without specific techniques or conditions indicated in the embodiments, they shall be carried out according to the techniques or conditions described in the literature in the art or according to the product specifications. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0045] Example 1

[0046] This embodiment provides an extractant, and the structural formula of the extractant is as follows:

[0047] 。

[0048] The synthesis route diagram of the extractant is as Figure 1 shown, and specifically includes the following steps:

[0049] A1. Add 1 mol of histidine (A) and 0.6 mol of copper chloride to 5 L of deionized water at 60 °C, adjust the pH of the solution to 9 with sodium hydroxide, maintain the temperature at 60 °C, and stir for 24 h. Evaporate the solution to a volume of 1 L, filter, and collect the solid. Add the collected solid to 5 L of ethanol solution, heat to 40 °C, stir and dissolve for 36 h, collect the solution phase, and perform vacuum distillation to collect the precipitated bright blue scaly solid (B), with a yield of 18 - 20%.

[0050] A2. Add 0.5 mol of B and 0.7 mol of 1-bromobutane to 1 L of absolute ethanol, add an appropriate amount of sodium hydroxide, and the concentration of sodium hydroxide is 0.1 mol / L. Under the condition of 80 °C, reflux and react for 36 h. After the reaction is completed, use vacuum distillation to remove the solvent ethanol and excess 1-bromobutane, collect the solid (C), add saturated ammonia water, dissolve it by ultrasonic treatment, filter, and remove copper hydroxide. Then add deionized water, dissolve it by ultrasonic treatment, and filter and wash until it is weakly alkaline or neutral. Since the subsequent reaction needs to be carried out under alkaline conditions, it is not necessary to wash repeatedly. Since the product of step A2 contains part of sodium hydroxide, the cumulative yield is calculated together with step A3 in the subsequent steps.

[0051] A3. Add the product of step A2 to an excessive CS2 solution, the mass concentration of the solid in the CS2 solution is 400 g / L, add sodium hydroxide, and the mass concentration of sodium hydroxide in the CS2 solution is 100 g / L. Heat to reflux at 40 °C and react for 3 h. After the reaction is completed, perform vacuum distillation on the solution to remove the excess carbon disulfide. Use dilute hydrochloric acid (V 盐酸 :V 去离子水 = 1:10) to adjust the pH of the residual solution to neutral, and perform vacuum rotary evaporation at 70 °C in a water bath until all the liquid evaporates to obtain a bright yellow oily compound, product D, that is, the extractant, with a yield of 72 - 76%. Its physical diagram is as Figure 2 shown.

[0052] Since the thioester group in the extractant of Example 1 is unstable under neutral and acidic conditions, a small amount of sodium hydroxide solution needs to be added to adjust it to alkaline (pH = 10) before analysis. The nuclear magnetic resonance hydrogen spectrum of the extractant obtained in Example 1 under alkaline conditions (pH = 10) is as Figure 3 shown.

[0053] The extractant prepared in Example 1 was dissolved in deuterated solvent D2O for 1H NMR test, and the test results are as Figure 3 shown in (a) of. It can be seen that the peak intensity of the deuterated solvent is much higher than that of the extractant, indicating that the solubility of the extractant in the aqueous phase is limited under alkaline conditions, which is beneficial to avoiding the residue of the extractant in the aqueous phase and secondary pollution to the water body.

[0054] The range of 1H NMR chemical shift from 0.5 to 4 ppm was magnified, as shown in Figure 3 (b) of. It can be seen that 1HNMR (D2O, 400MHZ): δ8.50 (H, thioamide N-H), δ6.80 - 7.50 (2H, imidazole ring H), δ2.75~2.85(4H, -CH2-CH2-), δ2.90~3.20 (4H, -CH2- fragment of the substituents at the 1,4 positions of the imidazole ring), δ3.70 (1H, -CH).

[0055] Example 2

[0056] This example provides a method for purifying copper-containing cyanide wastewater with an extractant. The extractant used is the extractant prepared in Example 1; the specific steps are as follows:

[0057] S1. Mix the extractant with sulfonated kerosene at a volume ratio of 1:10 and dissolve it by ultrasonic treatment to obtain an extractant dilution.

[0058] S2. Adjust the pH of the copper-containing cyanide solution to 11 with sodium hydroxide;

[0059] At room temperature, take 10 ml of the extractant dilution in step S1 and put it into 50 mL of copper-containing cyanide electroplating wastewater with a copper ion concentration of 100 ppm. In a water bath oscillator at 25 °C, after shaking for 5 min, separate the organic phase, and detect the copper concentration in the inorganic liquid phase solution by ICP-OES, so as to calculate the extraction rate of copper in the solution by the extractant.

[0060] Examples 3 - 4 and Comparative Examples 1 - 6

[0061] Examples 3 - 4 and Comparative Examples 1 - 6 respectively provide a method for purifying copper-containing cyanide wastewater with an extractant. Compared with Example 2, the only difference is that the pH value of the wastewater is different (adjust the pH value to a predetermined value with sodium hydroxide or hydrochloric acid). As shown in Table 1, other experimental parameters and conditions are basically the same as those in Example 2, and will not be elaborated here.

[0062] Table 1 pH values and extraction effects of Examples 2 - 4 and Comparative Examples 1 - 6

[0063]

[0064] —Indicates below the detection limit of ICP-OES.

[0065] As can be seen from Table 1, the extractant prepared in Example 1 has high extraction ability for copper in the copper-containing cyanide waste liquid within a specific pH range (9 - 11), and the extraction effect reaches over 96.0%. When pH is greater than or equal to 12, part of the copper in the liquid phase precipitates, separating from the inorganic solution system and unable to undergo mass transfer reaction with the organic solution phase, resulting in the inability to extract the precipitated copper and thus reducing the final extraction effect. When pH rises to 14, most of the copper exists in the form of precipitate (copper hydroxide). Since the solubility of copper hydroxide is low, there is only a small amount of copper hydroxide in the aqueous phase, and the dissolved copper hydroxide in the aqueous phase is extracted by the extractant, with the final extraction rate being only 3%.

[0066] It can be seen that when pH is 8, the carboxyl group of the active site in the extractant is not activated, and the leaching effect of copper is limited, only 43.1%. When pH is less than or equal to 7, the extractant exists in the form of neutral molecules or protons, and the active sites S - and the carboxyl group are not activated and unable to bond with copper ions, resulting in the inability to extract copper.

[0067] Examples 5 - 12

[0068] In Examples 5 - 12, experiments were conducted on extracting and separating copper from the mixed ion solution (a solution with multiple coexisting ions) using the extractant prepared in Example 1. The main difference among Examples 5 - 12 lies in the different concentrations of metal ions in the solution to be treated. The specific operation steps are as follows:

[0069] A series of cyanide co - mixed solutions containing different concentration ratios of copper, gold, silver, arsenic, and iron were prepared, and the pH of the cyanide co - mixed solution was 10 (when pH is 11, part of the arsenic precipitates, so pH was selected as 10).

[0070] The extractant prepared in Example 1 was mixed with sulfonated kerosene at a volume ratio of 1:10 and ultrasonically dissolved to obtain a diluted extractant solution; 10 ml of the diluted extractant solution was added to 50 mL of the solution to be treated with different concentrations respectively. After shaking for 20 min, the inorganic liquid phase was taken, and the concentrations of various metal ions in the inorganic liquid phase solution were detected by ICP - OES, thereby calculating the extraction rate.

[0071] The extraction effects of the extractant prepared in Example 1 on various metal ions in the co - mixed solution are shown in Table 2.

[0072] Table 2 Extraction ability of the extractant for various metal ions in the mixed ion solution

[0073]

[0074] —Indicates below the detection limit of ICP-OES.

[0075] As can be seen from Table 2, the extractant has a selective extraction effect on copper in the cyanide waste liquid, without extracting gold, silver, and arsenic ions. It will extract a small amount of iron ions, and the extraction rate is less than 13%. The main reason is that some divalent iron forms stable ferrocyanide ions with cyanide. The stability of ferrocyanide ions is at the same order of magnitude as the chelation product of ferrous ions and the extractant. Furthermore, some ferrocyanide ions undergo ion exchange reactions with the extractant, resulting in a small amount of co-extraction.

[0076] Examples 13 - 16 and Comparative Examples 7 - 8

[0077] Examples 13 - 16 and Comparative Examples 7 - 8 were used to conduct experiments on extracting copper from copper-containing solutions with different cyanide concentrations using the extractant prepared in Example 1. The main difference between Examples 13 - 16 and Comparative Examples 7 - 8 is the different cyanide concentrations in the solution to be treated. The specific operation steps are as follows:

[0078] A series of copper-containing solutions with different cyanide concentrations were prepared, with the cyanide concentration based on the total cyanide concentration. Among them, the concentration of copper analyzed by ICP - OES was 25 mg / L, and the pH of the cyanide solution was 10.

[0079] The extractant prepared in Example 1 was mixed with sulfonated kerosene at a volume ratio of 1:10 and dissolved by ultrasonic to obtain a diluted extractant solution; 100 ml of the diluted extractant solution was added to 50 mL of the solution to be treated with different cyanide concentrations respectively. After shaking for 20 min, the inorganic liquid phase was taken, and the concentration of copper ions in the inorganic liquid phase solution was detected by ICP - OES to calculate the extraction rate.

[0080] The extraction effect of the extractant prepared in Example 1 on copper-containing solutions with different cyanide concentrations is shown in Table 3.

[0081] Table 3 Extraction ability of the extractant for copper in copper-containing solutions with different cyanide concentrations

[0082]

[0083] As can be seen from Table 3, the extractant has a good extraction effect on copper in cyanide waste liquid with a cyanide concentration of 100 - 2000 mg / L, and the extraction rate is greater than 90%. When the cyanide concentration is greater than 2000 mg / L, the extraction rate of copper drops below 90%. The main reason is that the reaction of ion exchange extraction of copper by cyanide and the extractant is essentially a competitive chelation / complexation reaction, and the concentrations of the two substances have a direct impact on the direction of the competitive reaction. The main reason for not conducting comparative experiments with a cyanide concentration less than 100 mg / L is that the amount of cyanide substance cannot fully meet the theoretical value required by copper ions in the copper ion system with complex valence states, and some excess copper ions will exist in the form of precipitation, interfering with the experiment.

[0084] The cyanide-containing copper wastewater can be one or more of the residual copper-containing cyanide waste liquid from the activated carbon adsorption of the cyanide gold extraction solution, the residual copper-containing cyanide waste liquid from the ion exchange resin adsorption of the cyanide gold extraction solution, the copper-containing cyanide electroplating waste liquid, and the copper plating rinsing wastewater.

[0085] It should be noted that this application is not limited to the above embodiments. The above embodiments are only examples, and the embodiments with the same composition and the same effect as the technical idea within the scope of the technical solution of this application are included in the technical scope of this application. In addition, within the scope of not departing from the gist of this application, various modifications that those skilled in the art can think of to the embodiments, and other ways constructed by combining some of the constituent elements in the embodiments are also included in the scope of this application.

Claims

1. An extractant, characterized in that, The structural formula of the extractant is as follows: 。 2. A method for purifying copper-containing cyanide wastewater with an extractant, which uses the extractant described in claim 1 for extraction, and is characterized in that, It includes the following steps: The cyanide-containing copper wastewater is one or more of the copper-containing cyanide waste liquid remaining after the activated carbon adsorption of the cyanide gold extraction solution, the copper-containing cyanide waste liquid remaining after the ion exchange resin adsorption of the cyanide gold extraction solution, the copper-containing cyanide electroplating waste liquid, and the copper plating rinsing wastewater; copper exists in the solution in the form of [Cu(CN)2] - , [Cu(CN)3] 2- , [Cu(CN)4] 3- form; S1. Mix and dissolve the extractant with a diluent to obtain an extractant diluent; the diluent is sulfonated kerosene. S2. Add the extractant diluent to the copper-containing cyanide alkaline solution to achieve selective extraction of copper in the cyanide solution; the pH range of the copper-containing cyanide alkaline solution is 9 - 11.

3. The method for purifying copper cyanide-containing wastewater with an extractant according to claim 2, characterized in that, In the extractant diluent, the volume ratio of the extractant to the diluent is 1:(10 - 100).

4. The method for purifying copper cyanide-containing wastewater with an extractant according to claim 2, characterized in that, In the copper-containing cyanide alkaline solution, the concentration range of free cyanide is 100 mg / L - 1000 mg / L, and the concentration range of total cyanide is 100 mg / L - 2000 mg / L.

5. The method for purifying copper-containing cyanide wastewater with an extractant according to claim 2, characterized in that, The volume ratio of the extractant diluent to the copper-containing cyanide alkaline solution is 1:(1 - 10).

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