THIODIGLYCOLAMIC ACID EXTRACTANT, AND PREPARATION METHOD AND USE THEREOF

Abstract

The present disclosure provides a thiodiglycolamic acid extractant, and a preparation method and use thereof, belonging to the technical fields of extractant synthesis and extraction separation in the field of hydrometallurgy. In the present disclosure, the preparation method includes: mixing thiodiglycolic anhydride, an alkyl-substituted secondary amine, and an organic reagent in proportion; subjecting a resulting mixed reactant to a reaction I by stirring in an ice-water bath for 10 min to 60 min, and then to a reaction II by stirring at 20 C. to 50 C. for 6 h to 24 h; after the reaction II is completed, conducting extraction on an obtained product, and subjecting an obtained organic phase to washing, drying, suction filtration, and rotary evaporation to obtain the extractant.

Claims

1.-17. (canceled)

18. A thiodiglycolamic acid extractant, having a structural formula shown in formula 1: ##STR00006## wherein in formula 1, R.sub.1 and R.sub.2 are independently linear or branched alkyl, and there are totally six carbon atoms in R.sub.1 and R.sub.2.

19. The thiodiglycolamic acid extractant according to claim 18, wherein there are totally 7 to 24 carbon atoms in R.sub.1 and R.sub.2.

20. The thiodiglycolamic acid extractant according to claim 18, wherein the thiodiglycolamic acid extractant is selected from the group consisting of N,N-diisooctyl-3-thiodiglycolamic acid, N,N-methyloctyl-3-thiodiglycolamic acid, N,N-di-n-octyl-3-thiodiglycolamic acid, and N,N-di-n-hexyl-3-thiodiglycolamic acid.

21. A preparation method of the thiodiglycolamic acid extractant according to claim 18, comprising the following steps: mixing thiodiglycolic anhydride, an alkyl-substituted secondary amine, and an organic reagent in proportion; subjecting a resulting mixed reactant to a reaction I by stirring in an ice-water bath for 10 min to 60 min, and then to a reaction II by stirring at 20 C. to 50 C. for 6 h to 24 h; after the reaction II is completed, subjecting an obtained organic phase to washing, drying, and suction filtration; and subjecting an obtained organic phase filtrate to vacuum distillation to remove a solvent, to obtain the thiodiglycolamic acid extractant.

22. The preparation method according to claim 21, wherein there are totally 7 to 24 carbon atoms in R.sub.1 and R.sub.2.

23. The preparation method according to claim 21, wherein the thiodiglycolamic acid extractant is selected from the group consisting of N,N-diisooctyl-3-thiodiglycolamic acid, N,N-methyloctyl-3-thiodiglycolamic acid, N,N-di-n-octyl-3-thiodiglycolamic acid, and N,N-di-n-hexyl-3-thiodiglycolamic acid.

24. The preparation method according to claim 21, wherein the alkyl-substituted secondary amine has a structural formula shown in formula 2: ##STR00007## wherein R.sub.1 and R.sub.2 are independently linear or branched alkyl, and there are totally 7 to 24 carbon atoms in R.sub.1 and R.sub.2.

25. The preparation method according to claim 21, wherein the alkyl-substituted secondary amine is any one selected from the group consisting of diisooctylamine, di-n-octylamine, di-n-hexylamine, and N-methyloctylamine.

26. The preparation method according to claim 24, wherein the alkyl-substituted secondary amine is any one selected from the group consisting of diisooctylamine, di-n-octylamine, di-n-hexylamine, and N-methyloctylamine.

27. The preparation method according to claim 21, wherein the thiodiglycolic anhydride and the alkyl-substituted secondary amine are at a molar ratio of 1:1 to 1:2.

28. The preparation method according to claim 21, wherein the organic reagent is any one selected from the group consisting of dichloromethane, chloroform, tetrahydrofuran, acetonitrile, N,N-dimethylformamide (DMF), and toluene.

29. The preparation method according to claim 21, wherein the washing specifically comprises: washing the organic phase with a dilute hydrochloric acid solution to remove excess alkyl-substituted secondary amine, and then repeatedly washing with deionized water until a pH value is 3 to 4.

30. A use method of the thiodiglycolamic acid extractant according to claim 18 in extraction of precious metal ions in an acidic feed liquid, comprising the following steps: (1) dissolving the thiodiglycolamic acid extractant in a diluent to obtain an extractant solution; and (2) mixing the extractant solution obtained in step (1) with an acidic precious metal feed liquid in a constant-temperature oscillator to conduct extraction, such that a precious metal is extracted into the extractant solution to allow for enrichment.

31. The use method according to claim 30, wherein in step (1), the diluent is one or more selected from the group consisting of toluene, dichloromethane, kerosene, and n-heptane.

32. The use method according to claim 30, wherein in step (1), the extractant solution has a concentration of 0.05 mol/L to 0.2 mol/L.

33. The use method according to claim 30, wherein in step (2), the acidic precious metal feed liquid comprises one or more of gold ions, palladium ions, copper ions, lead ions, cobalt ions, nickel ions, calcium ions, and magnesium ions.

34. The use method according to claim 30, wherein in step (2), the acidic precious metal feed liquid has a pH value of 0 to 5.

35. The use method according to claim 31, wherein in step (2), the extractant solution and the acidic precious metal feed liquid are at a volume ratio of 1:10.

36. The use method according to claim 30, wherein in step (2), the constant-temperature oscillator has an operating temperature of 20 C. to 30 C.

37. The use method according to claim 30, wherein in step (2), the constant-temperature oscillator has a rotational speed of 100 rpm to 300 rpm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 shows an infrared spectrum of N,N-diisooctyl-3-thiodiglycolamic acid prepared in Example 1 of the present disclosure;

[0042] FIG. 2 shows an .sup.1H-NMR spectrogram of the N,N-diisooctyl-3-thiodiglycolamic acid prepared in Example 1 of the present disclosure in deuterated chloroform;

[0043] FIG. 3 shows an infrared spectrum of N,N-methyloctyl-3-thiodiglycolamic acid prepared in Example 2 of the present disclosure;

[0044] FIG. 4 shows an .sup.1H-NMR spectrogram of the N,N-methyloctyl-3-thiodiglycolamic acid prepared in Example 2 of the present disclosure in deuterated chloroform;

[0045] FIG. 5 shows an infrared spectrum of N,N-di-n-octyl-3-thiodiglycolamic acid prepared in Example 3 of the present disclosure;

[0046] FIG. 6 shows an .sup.1H-NMR spectrogram of the N,N-di-n-octyl-3-thiodiglycolamic acid prepared in Example 3 of the present disclosure in deuterated chloroform;

[0047] FIG. 7 shows an infrared spectrum of N,N-di-n-hexyl-3-thiodiglycolamic acid prepared in Example 4 of the present disclosure; and

[0048] FIG. 8 shows an .sup.1H-NMR spectrogram of the N,N-di-n-hexyl-3-thiodiglycolamic acid prepared in Example 4 of the present disclosure in deuterated chloroform.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] The present disclosure provides a thiodiglycolamic acid extractant, having a structural formula as follows:

##STR00004## [0050] R.sub.1 and R.sub.2 are independently linear or branched alkyl, and there are totally greater than six, preferably 7 to 24 carbon atoms in R.sub.1 and R.sub.2.

[0051] The present disclosure further provides a preparation method of the thiodiglycolamic acid extractant, including the following steps: [0052] mixing thiodiglycolic anhydride, an alkyl-substituted secondary amine, and an organic reagent in proportion in a 500 mL round-bottom flask; subjecting a resulting mixed reactant to a reaction I by stirring in an ice-water bath for 10 min to 60 min, and then to a reaction II by stirring at 20 C. to 50 C. for 6 h to 24 h; after the reaction II is completed, subjecting an obtained organic phase to washing with a dilute hydrochloric acid solution to remove excess secondary amine, repeated washing with deionized water to a pH value of 3 to 4, drying with anhydrous magnesium sulfate, and vacuum suction filtration; and subjecting an obtained organic phase filtrate to rotary evaporation to remove a solvent, to obtain the thiodiglycolamic acid extractant. The alkyl-substituted secondary amine has a structural formula as follows:

##STR00005##

where [0053] R.sub.1 and R.sub.2 are independently linear or branched alkyl, and there are totally 7 to 24 carbon atoms in R.sub.1 and R.sub.2.

[0054] The disclosure will be further described in detail in conjunction with examples. The examples are implemented on the premise of the technology of the disclosure, and detailed embodiments and specific operating procedures are now given to illustrate that the disclosure is inventive, but the scope of protection of the disclosure is not limited to the following examples.

[0055] In the present disclosure, all equipment and raw materials used are commercially available or are commonly used in the art. All methods in the following examples are conventional methods in the art, unless otherwise specified.

Example 1

[0056] In this example, a preparation method of an N,N-diisooctyl-3-thiodiglycolamic acid extractant included the following steps: [0057] 0.2 mmol of thiodiglycolic anhydride, 0.22 mmol of diisooctylamine, and 200 mL of tetrahydrofuran were mixed in a 500 mL round-bottom flask; a resulting mixed reactant was subjected to a reaction I by stirring in an ice-water bath for 30 min, and then to a reaction II by stirring at 40 C. for 24 h; after the reaction II was completed, an obtained organic phase was subjected to washing with a dilute hydrochloric acid solution to remove excess diisooctylamine, followed by washing with deionized water until a pH value was 4, drying with anhydrous magnesium sulfate, and suction filtration; and an obtained organic phase filtrate was subjected to vacuum distillation to remove a solvent, to obtain the N,N-diisooctyl-3-thiodiglycolamic acid extractant.

[0058] The product prepared in this example was characterized, and the results were shown in FIG. 1 to FIG. 2.

[0059] FIG. 1 showed an infrared spectrum of the product prepared in Example 1. The main characteristic absorption peak was a peak at 2,926 cm.sup.1, indicating that there was stretching vibration of a saturated CH bond. The peak at 1,723 cm.sup.1 was a stretching vibration absorption peak of a CO bond of the carboxyl, the peak at 1,599 cm.sup.1 was a stretching vibration absorption peak of a CO bond of the amide, the peak at 1,457 cm.sup.1 was a stretching vibration absorption peak of a CN bond of the amide, and the peak at 1,269 cm.sup.1 was an asymmetric stretching vibration absorption peak of CSC. These characteristic peaks indicated the presence of carboxylic acid, amide, and thioether functional groups.

[0060] FIG. 2 showed an .sup.1H-NMR spectrogram of the product prepared in Example 1 in deuterated chloroform. The chemical shifts of each proton were as follows: 9.55 (s, 1H, COOH), 3.52 (s, 2H, SCH.sub.2), 3.37 (s, 2H, CH.sub.2S), 3.20-3.33 (m, 4H, 2CH.sub.2N), 2.86-2.88 (m, 2H, 2CH), 1.24-1.33 (m, 16H, 8CH.sub.2), 0.86-0.91 (m, 12H, 4CH.sub.3).

[0061] It was known from the data in FIG. 1 and FIG. 2 that the product prepared in Example 1 of the present disclosure was the N,N-diisooctyl-3-thiodiglycolamic acid.

Example 2

[0062] In this example, a preparation method of an N,N-methyloctyl-3-thiodiglycolamic acid extractant included the following steps: [0063] 0.2 mmol of thiodiglycolic anhydride, 0.4 mmol of N-methyloctylamine, and 300 mL of DMF were mixed in a 500 mL round-bottom flask; a resulting mixed reactant was subjected to a reaction I by stirring in an ice-water bath for 30 min, and then to a reaction II by stirring at 20 C. for 24 h; after the reaction II was completed, an obtained organic phase was subjected to washing with a dilute hydrochloric acid solution to remove excess N-methyloctylamine, followed by washing with deionized water until a pH value was 4, drying with anhydrous magnesium sulfate, and suction filtration; and an obtained organic phase filtrate was subjected to vacuum distillation to remove a solvent, to obtain the N,N-methyloctyl-3-thiodiglycolamic acid extractant.

[0064] The extractant prepared in this example was characterized, and the results were shown in FIG. 3 to FIG. 4.

[0065] FIG. 3 showed an infrared spectrum of the product prepared in this example. The main characteristic absorption peak was a peak at 2,924 cm.sup.1, indicating that there was stretching vibration of a saturated CH bond. The peak at 1,723 cm.sup.1 was a stretching vibration absorption peak of a CO bond of the carboxyl, the peak at 1,600 cm.sup.1 was a stretching vibration absorption peak of a CO bond of the amide, the peak at 1,403 cm.sup.1 was a stretching vibration absorption peak of a CN bond of the amide, and the peak at 1,261 cm.sup.1 was an asymmetric stretching vibration absorption peak of CSC. These characteristic peaks indicated the presence of carboxylic acid, amide, and thioether functional groups.

[0066] FIG. 4 showed an .sup.1H-NMR spectrogram of the product prepared in this example in deuterated chloroform. The chemical shifts of each proton were as follows: 10.0 (s, 1H, COOH), 3.53 (s, 2H, SCH.sub.2), 3.40 (s, 2H, CH.sub.2S), 3.30-3.37 (m, 2H, CH.sub.2N), 2.96-3.07 (m, 3H, CH.sub.3N), 1.28-1.29 (m, 8H, 4CH.sub.2), 0.87-0.89 (m, 3H, CH.sub.3).

[0067] It was known from the data in FIG. 3 and FIG. 4 that the product prepared in this example was the N,N-methyloctyl-3-thiodiglycolamic acid.

Example 3

[0068] In this example, a preparation method of an N,N-di-n-octyl-3-thiodiglycolamic acid extractant included the following steps: [0069] 0.2 mmol of thiodiglycolic anhydride, 0.3 mmol of di-n-octylamine, and 250 mL of dichloromethane were mixed in a 500 mL round-bottom flask; a resulting mixed reactant was subjected to a reaction I by stirring in an ice-water bath for 30 min, and then to a reaction II by stirring at 50 C. for 24 h; after the reaction II was completed, an obtained organic phase was subjected to washing with a dilute hydrochloric acid solution to remove excess di-n-octylamine, followed by washing with deionized water until a pH value was 4, drying with anhydrous magnesium sulfate, and suction filtration; and an obtained organic phase filtrate was subjected to vacuum distillation to remove a solvent, to obtain the N,N-di-n-octyl-3-thiodiglycolamic acid extractant.

[0070] The extractant prepared in this example was characterized, and the results were shown in FIG. 5 to FIG. 6.

[0071] FIG. 5 showed an infrared spectrum of the product prepared in Example 3. The main characteristic absorption peak was a peak at 2,923 cm.sup.1, indicating that there was stretching vibration of a saturated CH bond. The peak at 1,724 cm.sup.1 was a stretching vibration absorption peak of a CO bond of the carboxyl, the peak at 1,600 cm.sup.1 was a stretching vibration absorption peak of a CO bond of the amide, the peak at 1,464 cm.sup.1 was a stretching vibration absorption peak of a CN bond of the amide, and the peak at 1,277 cm.sup.1 was an asymmetric stretching vibration absorption peak of CSC. These characteristic peaks indicated the presence of carboxylic acid, amide, and thioether functional groups.

[0072] FIG. 6 showed an .sup.1H-NMR spectrogram of the product prepared in Example 3 in deuterated chloroform. The chemical shifts of each proton were as follows: 9.9 (s, 1H, COOH), 3.50 (s, 2H, SCH.sub.2), 3.38 (s, 2H, CH.sub.2S), 3.25-3.34 (m, 4H, 2CH.sub.2N), 1.54-1.61 (m, 4H, 2-CH.sub.2CH.sub.2N), 1.28-1.29 (m, 10H, 5CH.sub.2), 0.88-0.90 (m, 6H, 2CH.sub.3).

[0073] It was known from the data in FIG. 5 and FIG. 6 that the product prepared in this example was the N,N-di-n-octyl-3-thiodiglycolamic acid.

Example 4

[0074] In this example, a preparation method of an N,N-di-n-hexyl-3-thiodiglycolamic acid extractant included the following steps: [0075] 0.2 mmol of thiodiglycolic anhydride, 0.2 mmol of di-n-hexylamine, and 200 mL of chloroform were mixed in a 500 mL round-bottom flask; a resulting mixed reactant was subjected to a reaction I by stirring in an ice-water bath for 30 min, and then to a reaction II by stirring at 30 C. for 24 h; after the reaction II was completed, an obtained organic phase was subjected to washing with a dilute hydrochloric acid solution to remove excess di-n-hexylamine, followed by washing with deionized water until a pH value was 4, drying with anhydrous magnesium sulfate, and suction filtration; and an obtained organic phase filtrate was subjected to vacuum distillation to remove a solvent, to obtain the N,N-di-n-hexyl-3-thiodiglycolamic acid extractant.

[0076] The product prepared in this example was characterized, and the results were shown in FIG. 7 to FIG. 8.

[0077] FIG. 7 showed an infrared spectrum of the product prepared in Example 4. The main characteristic absorption peak was a peak at 2,926 cm.sup.1, indicating that there was stretching vibration of a saturated CH bond. The peak at 1,723 cm.sup.1 was a stretching vibration absorption peak of a CO bond of the carboxyl, the peak at 1,598 cm.sup.1 was a stretching vibration absorption peak of a CO bond of the amide, the peak at 1,463 cm.sup.1 was a stretching vibration absorption peak of a CN bond of the amide, and the peak at 1,271 cm.sup.1 was an asymmetric stretching vibration absorption peak of CSC. These characteristic peaks indicated the presence of carboxylic acid, amide, and thioether functional groups.

[0078] FIG. 8 showed an .sup.1H-NMR spectrogram of the product prepared in Example 4 in deuterated chloroform. The chemical shifts of each proton were as follows: 10.1 (s, 1H, COOH), 3.51 (s, 2H, SCH.sub.2), 3.38 (s, 2H, CH.sub.2S), 3.26-3.33 (m, 4H, 2CH.sub.2N), 1.54-1.60 (m, 4H, 2-CH.sub.2CH.sub.2N), 1.29-1.31 (m, 6H, 3CH.sub.2), 0.88-0.90 (m, 6H, 2CH.sub.3).

[0079] It was known from the data in FIG. 7 and FIG. 8 that the product prepared in this example was the N,N-di-n-hexyl-3-thiodiglycolamic acid.

Use Example

[0080] Each of the extractants prepared in the above examples of the present disclosure were used to extract precious metal ions in an acidic feed liquid.

[0081] In the following use examples, a precious metal feed liquid had the same composition, specifically including: gold ions, palladium ions, copper ions, lead ions, cobalt ions, nickel ions, calcium ions, and magnesium ions. Each type of the metal ions had a concentration of 100 mg/L. A configuration method of the feed liquid included: a standard solution of each metal ion with a concentration of 1,000 mg/L was diluted in a volumetric flask, and then the pH value of a resulting diluted solution was adjusted with a 0.5 mol/L HCl solution and a 0.5 mol/L NaOH solution, to obtain precious metal feed liquids with different pH values.

[0082] A calculation method of an extraction rate involved in each of the following use examples was as follows: [0083] the extraction rate was represented by E (%),

[00001]$E=\frac{C_0-C_e}{C_0}100\%;$ where [0084] C.sub.0: a metal ion concentration in an initial aqueous solution (mg/L); and [0085] C.sub.e: a metal ion concentration in an aqueous phase after extraction equilibrium (mg/L).

Use Example 1

[0086] The N,N-methyloctyl-3-thiodiglycolamic acid extractant prepared in Example 2 was used to extract precious metal ions in an acidic feed liquid. A specific use method included the following steps: [0087] 2.75 g of the N,N-methyloctyl-3-thiodiglycolamic acid extractant prepared in Example 2 was dissolved in kerosene to obtain a 0.1 mol/L extractant solution; and [0088] the 0.1 mol/L extractant solution and a precious metal feed liquid with a pH value of 1.03 were mixed in a constant-temperature oscillator at a volume ratio of 1:10, and subjected to extraction by oscillating at 230 rpm and a constant temperature of 25 C. for 15 min; concentrations of metal ions in an aqueous phase were determined before and after the extraction, and an extraction rate of each metal ion was calculated. The specific results were shown in Table 1.

Use Example 2

[0089] The N,N-di-n-hexyl-3-thiodiglycolamic acid extractant prepared in Example 4 was used to extract precious metal ions in an acidic feed liquid. A specific use method included the following steps: [0090] 3.18 g of the N,N-di-n-hexyl-3-thiodiglycolamic acid extractant prepared in Example 4 was dissolved in kerosene to obtain a 0.1 mol/L extractant solution; and [0091] the 0.1 mol/L extractant solution and a precious metal feed liquid with a pH value of 1.03 were mixed in a constant-temperature oscillator at a volume ratio of 1:10, and subjected to extraction by oscillating at 230 rpm and a constant temperature of 25 C. for 15 min; concentrations of metal ions in an aqueous phase were determined before and after the extraction, and an extraction rate of each metal ion was calculated. The specific results were shown in Table 1.

Use Example 3

[0092] The N,N-diisooctyl-3-thiodiglycolamic acid extractant prepared in Example 1 was used to extract precious metal ions in an acidic feed liquid. A specific use method included the following steps: [0093] 3.74 g of the N,N-diisooctyl-3-thiodiglycolamic acid extractant prepared in Example 1 was dissolved in kerosene to obtain a 0.1 mol/L extractant solution; and [0094] the 0.1 mol/L extractant solution and a precious metal feed liquid with a pH value of 1.03 were mixed in a constant-temperature oscillator at a volume ratio of 1:10, and subjected to extraction by oscillating at 230 rpm and a constant temperature of 25 C. for 15 min; concentrations of metal ions in an aqueous phase were determined before and after the extraction, and an extraction rate of each metal ion was calculated. The specific results were shown in Table 1.

Use Example 4

[0095] The N,N-di-n-octyl-3-thiodiglycolamic acid extractant prepared in Example 3 was used to extract precious metal ions in an acidic feed liquid. A specific use method included the following steps: [0096] 3.74 g of the N,N-di-n-octyl-3-thiodiglycolamic acid extractant was dissolved in kerosene to obtain a 0.1 mol/L extractant solution; and [0097] the 0.1 mol/L extractant solution and a precious metal feed liquid with a pH value of 1.03 were mixed in a constant-temperature oscillator at a volume ratio of 1:10, and subjected to extraction by oscillating at 230 rpm and a constant temperature of 25 C. for 15 min; concentrations of metal ions in an aqueous phase were determined before and after the extraction, and an extraction rate of each metal ion was calculated. The specific results were shown in Table 1.

TABLE-US-00001 TABLE 1 Comparison of extraction rate results in Use Examples 1 to 4 E (%) Use Example Au Pd Cu Pb Co Ni Ca Mg Use Example 1 86.68 99.47 10.21 8.21 10.08 10.74 0 16.87 Use Example 2 91.79 99.68 8.14 4.09 9.23 9.61 0 13.59 Use Example 3 98.32 99.93 6.55 1.41 8.55 8.77 0 12.5 Use Example 4 99.98 99.95 0.86 0 7.63 8.09 0 9.88

[0098] It was seen from the results in Table 1 that the longer a carbon chain substituted on the nitrogen atom in an extractant structure was, the higher the extraction rate of precious metal ions could be. Moreover, the higher the degree of branching of the carbon chain of the substituted alkyl was, the lower the extraction rate of precious metal ions could be. The reason was that as the carbon chain of the alkyl substituting on the nitrogen atom in the extractant structure grew, the stability of an extract compound formed between the extractant and the metal ions during the extraction was higher. This was beneficial to the extraction. However, the higher the degree of branching of the carbon chain of the substituted alkyl was, the greater the steric hindrance between the extractant and the metal ions could be, and was more unfavorable for the formation of the extract. Therefore, the extraction rate of metal ions decreased.

Use Example 5

[0099] The N,N-diisooctyl-3-thiodiglycolamic acid extractant prepared in Example 1 was used to extract precious metal ions in an acidic feed liquid. A specific use method included the following steps: [0100] 7.48 g of the N,N-diisooctyl-3-thiodiglycolamic acid extractant prepared in Example 1 was dissolved in kerosene to obtain a 0.2 mol/L extractant solution; and [0101] the 0.2 mol/L extractant solution and a precious metal feed liquid with a pH value of 1.03 were mixed in a constant-temperature oscillator at a volume ratio of 1:10, and subjected to extraction by oscillating at 230 rpm and a constant temperature of 25 C. for 15 min; concentrations of metal ions in an aqueous phase were determined before and after the extraction, and an extraction rate of each metal ion was calculated. The specific results were shown in Table 2.

Use Example 6

[0102] The N,N-diisooctyl-3-thiodiglycolamic acid extractant prepared in Example 1 was used to extract precious metal ions in an acidic feed liquid. A specific use method included the following steps: [0103] 7.48 g of the N,N-diisooctyl-3-thiodiglycolamic acid extractant was dissolved in kerosene to obtain a 0.2 mol/L extractant solution; and [0104] the 0.2 mol/L extractant solution and a precious metal feed liquid with a pH value of 0.3 were mixed in a constant-temperature oscillator at a volume ratio of 1:10, and subjected to extraction by oscillating at 230 rpm and a constant temperature of 25 C. for 15 min; concentrations of metal ions in an aqueous phase were determined before and after the extraction, and an extraction rate of each metal ion was calculated. The specific results were shown in Table 2.

Use Example 7

[0105] The N,N-diisooctyl-3-thiodiglycolamic acid extractant prepared in Example 1 was used to extract precious metal ions in an acidic feed liquid. A specific use method included the following steps: [0106] 7.48 g of the N,N-diisooctyl-3-thiodiglycolamic acid extractant was dissolved in kerosene to obtain a 0.2 mol/L extractant solution; and [0107] the 0.2 mol/L extractant solution and a precious metal feed liquid with a pH value of 2.43 were mixed in a constant-temperature oscillator at a volume ratio of 1:10, and subjected to extraction by oscillating at 230 rpm and a constant temperature of 25 C. for 15 min; concentrations of metal ions in an aqueous phase were determined before and after the extraction, and an extraction rate of each metal ion was calculated. The specific results were shown in Table 2.

Use Example 8

[0108] The N,N-diisooctyl-3-thiodiglycolamic acid extractant prepared in Example 1 was used to extract precious metal ions in an acidic feed liquid. A specific use method included the following steps: [0109] 7.48 g of the N,N-diisooctyl-3-thiodiglycolamic acid extractant was dissolved in kerosene to obtain a 0.2 mol/L extractant solution; and [0110] the 0.2 mol/L extractant solution and a precious metal feed liquid with a pH value of 3.2 were mixed in a constant-temperature oscillator at a volume ratio of 1:10, and subjected to extraction by oscillating at 230 rpm and a constant temperature of 25 C. for 15 min; concentrations of metal ions in an aqueous phase were determined before and after the extraction, and an extraction rate of each metal ion was calculated. The specific results were shown in Table 2.

Use Example 9

[0111] The N,N-diisooctyl-3-thiodiglycolamic acid extractant prepared in Example 1 was used to extract precious metal ions in an acidic feed liquid. A specific use method included the following steps: [0112] 7.48 g of the N,N-diisooctyl-3-thiodiglycolamic acid extractant was dissolved in kerosene to obtain a 0.2 mol/L extractant solution; and [0113] the 0.2 mol/L extractant solution and a precious metal feed liquid with a pH value of 4.05 were mixed in a constant-temperature oscillator at a volume ratio of 1:10, and subjected to extraction by oscillating at 230 rpm and a constant temperature of 25 C. for 15 min; concentrations of metal ions in an aqueous phase were determined before and after the extraction, and an extraction rate of each metal ion was calculated. The specific results were shown in Table 2.

TABLE-US-00002 TABLE 2 Comparison of extraction rate results in Use Examples 5 to 9 E (%) Use Example Au Pd Cu Pb Co Ni Ca Mg Use Example 99.25 99.97 7.14 2.06 18.14 18.42 0 25.02 5 Use Example 94.73 98.95 9.27 4.91 20.10 20.67 0 25.97 6 Use Example 99.78 100 5.41 0 18.85 18.99 0 23.04 7 Use Example 99.98 100 3.28 0 18.71 18.89 0 23.06 8 Use Example 100 100 2.12 0 15.39 15.65 0 21.37 9

[0114] As shown in the results of Table 2, the N,N-diisooctyl-3-thiodiglycolamic acid extractants of Use Examples 5 to 9 had an extraction rate of precious metals increased with an increase of the pH value, and had an extraction rate of base metals decreased with the increase of the pH value. Therefore, the precious metals could be effectively separated from the base metals by adjusting an appropriate pH value.

[0115] The above are merely preferred implementations of the present disclosure. It should be noted that several improvements and modifications may further be made by a person of ordinary skill in the art without departing from the principle of the present disclosure, and such improvements and modifications should also be deemed as falling within the protection scope of the present disclosure.