Extracting agent, preparation method thereof and application of extracting agent in metal separation

Abstract

The invention discloses an extraction agent, a preparation method thereof and application of the extraction agent to metal separation. The invention discloses a phosphoryl compound, which is a compound as shown in a formula I or a salt thereof. The extraction agent provided by the invention is good in selectivity of separating thulium, ytterbium and lutetium elements, and high in extraction rate of extracting gallium, indium, nickel, cobalt and copper elements; the extractant is stable in structure, can be recycled for multiple times and is not easy to decompose.

Description

Technical Field

[0001] This invention relates to the field of extraction and separation technology, and in particular to an extractant, its preparation method, and its application in separating metals. Background Technology

[0002] Solvent extraction, a core separation technology in modern hydrometallurgy, focuses on the highly selective extraction and purification of metal ions from complex, low-grade raw materials. Developed since the nuclear industry in the 1940s, it has become an irreplaceable method for efficient metal separation.

[0003] Thulium, ytterbium, and lutetium, as heavy rare earth elements, have extremely important applications in fields such as fiber optic communication, lasers, nuclear medicine, and catalysis due to their unique physicochemical properties. The global reserves of these heavy rare earth elements are scarce and unevenly distributed, making the development of efficient separation and recovery technologies of great significance.

[0004] Gallium and indium, as rare metals, are listed as strategic critical minerals by many countries worldwide due to their unique physicochemical properties and irreplaceable applications. These two metals are extremely rare in nature, making the development of more mature extraction and separation technologies crucial. They are not only core materials for high-end industries such as semiconductors, optoelectronics, and new energy, but also an invisible pillar of national competitiveness.

[0005] Nickel, cobalt, and copper, as the "three pillars" of the modern industrial system, play an irreplaceable strategic role in the new energy revolution, high-end manufacturing, and national defense security. Their importance lies not only in their massive market size but also in their fundamental support for carbon neutrality goals and technological industrial upgrading. With the obsolescence of previous generations of technological products, the development of nickel, cobalt, and copper recycling technologies is becoming increasingly crucial. Summary of the Invention

[0006] The technical problem this invention aims to solve is to overcome the shortcomings of existing extractants, such as easy decomposition, high back-extraction acidity during recycling, difficult synthesis, high cost, poor extraction selectivity, or low extraction rate. This invention provides an extractant, its preparation method, and its application in metal separation. The phosphoryl compounds provided by this invention are structurally stable as extractants, can be recycled multiple times, and are not prone to decomposition; they exhibit low back-extraction acidity during recycling, reducing pollution; no emulsification occurs during extraction, resulting in good extraction performance; and the extractant is easy to synthesize and inexpensive. Based on these advantages, the extractant of this invention exhibits good selectivity for separating thulium, ytterbium, and lutetium; and high extraction rates for extracting gallium, indium, nickel, cobalt, and copper.

[0007] The present invention solves the above-mentioned technical problems through the following technical solution:

[0008] This invention provides a phosphoryl compound, which is a compound of formula I or a salt thereof:

[0009] ,

[0010] in,

[0011] R1 and R2 are independently selected from C6-C 15 Alkyl, C6-C 15 Alkoxy groups and C6-C substituted with one or more C1-C6 alkyl groups 10 Aryl;

[0012] n is an integer selected from 1 to 6.

[0013] In some embodiments of the present invention, in R1 and R2, C6-C 15 Alkyl groups are C6-C 10 Alkyl groups, preferably C8-C9 straight-chain or branched alkyl groups; more preferably 2-ethylhexyl, 2,4,4-trimethylpentyl, 2,2,4-trimethylpentyl or 2,6-dimethylheptyl.

[0014] In some embodiments of the present invention, in R1 and R2, C6-C 15 Alkyl groups are branched C6-C 15 alkyl.

[0015] In some embodiments of the present invention, in R1 and R2, C6-C 15 The alkoxy group is a branched C6-C. 15 Alkyl group.

[0016] In some embodiments of the present invention, in R1 and R2, C6-C 15 The alkoxy group is C6-C. 10 Alkoxy group; preferably C8-C9 straight-chain or branched alkoxy group; for example, 2-ethylhexyloxy group.

[0017] In some embodiments of the invention, in R1 and R2, the C6-C alkyl group substituted with one or more C1-C6 alkyl groups... 10 The C1-C6 alkyl group in the aryl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, or tert-butyl.

[0018] In some embodiments of the invention, in R1 and R2, the C6-C alkyl group substituted with one or more C1-C6 alkyl groups... 10 C6-C in aryl 10 The aryl group is either phenyl or naphthyl.

[0019] In some embodiments of the present invention, R1 and R2 are independently selected from C6-C. 15 Alkyl or C6-C15 Alkoxy; preferably 2-ethylhexyl, 2,4,4-trimethylpentyl or 2-ethylhexyloxy.

[0020] In some embodiments of the present invention, n is 1 or 2; preferably 1.

[0021] In some embodiments of the present invention, the compound represented by Formula I is a compound represented by Formula III, Formula IV, or Formula V:

[0022] , , .

[0023] The present invention provides an extractant composition comprising a phosphoryl compound as described above, and a diluent.

[0024] In some embodiments of the present invention, the diluent is kerosene, heptane, octane, or dodecane; for example, dodecane.

[0025] In some embodiments of the present invention, the volume ratio of the phosphoryl compound to the diluent is 1:(1~20); preferably 1:(1~5); for example 1:3 or 1:4.

[0026] In some embodiments of the present invention, the molar volume ratio of the phosphoryl compound to the diluent is 0.01~2 mol / L; preferably 0.1~2 mol / L.

[0027] This invention provides a method for preparing a compound as described above, represented by Formula I, comprising the following steps:

[0028] Step 1: In a solvent and in the presence of a base, the compound shown in Formula II undergoes a substitution reaction with a halocarboxylic acid ester to obtain a reaction intermediate.

[0029] Step 2: In a solvent, in the presence of an acid or a base, the reaction intermediate undergoes a hydrolysis reaction to obtain the compound shown in Formula I.

[0030] ,

[0031] R1 and R2 are as described above.

[0032] In some embodiments of the present invention, in step 1, the solvent is an ether solvent; preferably diethyl ether, tetrahydrofuran, tert-butyl methyl ether or cyclopentyl methyl ether; for example, tetrahydrofuran, tert-butyl methyl ether or cyclopentyl methyl ether.

[0033] In some embodiments of the present invention, in step 1, the amount of solvent used is the conventional amount used in such reactions in the art; preferably, the molar volume ratio of the solvent to the compound shown in Formula II is 0.5 to 3 mol / L; for example, 1 mol / L.

[0034] In some embodiments of the present invention, in step 1, the alkali is selected from one or more of alkali metal hydroxides, alkali metal alkoxides, and alkali metal hydrides; preferably one or more of sodium hydroxide, potassium hydroxide, sodium ethoxide, and sodium hydride; for example, sodium hydroxide, sodium ethoxide, or sodium hydride.

[0035] In some embodiments of the present invention, in step 1, the molar ratio of the base to the compound as shown in Formula II is (1~3):1; preferably (1.2~1.8):1; for example, 1.05:1 or 1.2:1.

[0036] In some embodiments of the present invention, in step 1, the halocarboxylic acid ester is ethyl chloroacetate, tert-butyl bromoacetate, ethyl 3-bromopropionate, or tert-butyl 4-chlorobutyrate; for example, tert-butyl chloroacetate or tert-butyl bromoacetate.

[0037] In some embodiments of the present invention, in step 1, the molar ratio of the halocarboxylic acid ester to the compound shown in Formula II is (1~3):1; preferably (1.2~1.5):1; for example, 1.25:1 or 1.5:1.

[0038] In some embodiments of the present invention, in step 1, the temperature of the substitution reaction is 60~120°C, preferably 80~100°C; for example, 80°C or 90°C.

[0039] In some embodiments of the present invention, in step 1, the substitution reaction generally ends when the compound shown in Formula II disappears or the reaction intermediate no longer increases; the substitution reaction time is preferably 2 to 24 hours; more preferably 12 to 18 hours; for example, 8 hours.

[0040] In some embodiments of the present invention, in step 2, the solvent is a conventional solvent for such reactions in the art; preferably a haloalkane solvent; more preferably dichloromethane, 1,2-dichloroethane, trichloromethane or carbon tetrachloride; for example dichloromethane or 1,2-dichloroethane.

[0041] In some embodiments of the present invention, in step 2, the amount of the reaction intermediate depends on the amount of the compound shown in Formula II in step 1.

[0042] In some embodiments of the present invention, in step 2, the amount of solvent used is the conventional amount used in such reactions in the art; preferably, the molar volume ratio of the solvent to the compound shown in Formula II is 0.2~2 mol / L; for example, 0.8 mol / L.

[0043] In some embodiments of the present invention, in step 2, the acid or base is a conventional hydrolysis promoter for such reactions in the art; preferably sulfuric acid, hydrochloric acid, acetic acid, trifluoroacetic acid, sodium hydroxide, sodium carbonate or sodium ethoxide; for example, trifluoroacetic acid.

[0044] In some embodiments of the present invention, in step 2, the molar ratio of the acid or base to the compound as shown in Formula II is (1~5):1; for example, 3:1.

[0045] In some embodiments of the present invention, in step 2, the temperature of the hydrolysis reaction is 20~80℃, preferably 40~60℃; for example, 40℃.

[0046] In some embodiments of the present invention, in step 2, the hydrolysis reaction generally ends when the reaction intermediate disappears or the compound shown in Formula I no longer increases; the hydrolysis reaction time is preferably 1 to 12 hours; more preferably 2 to 6 hours; for example, 6 hours.

[0047] This invention provides a method for extracting metal ions, comprising the following steps:

[0048] The aforementioned extractant composition was used to extract a feed solution containing metal ions to obtain an organic phase containing metal ions.

[0049] The metal ions are selected from one or more of rare earth metal ions, gallium ions, indium ions, nickel ions, cobalt ions, and copper ions.

[0050] The valence state of the metal ions can be a common valence state of such metal ions in the art; preferably, the rare earth metal ions are trivalent; the gallium ions are trivalent; the indium ions are trivalent; the nickel ions are divalent; the cobalt ions are divalent; and the copper ions are divalent.

[0051] The raffinate obtained from the extraction can be used as the extraction target.

[0052] In some embodiments of the present invention, the volume ratio of the extractant composition to the feed liquid in the extraction is 1:(1~3); for example, 1:1 or 1:2.

[0053] In some embodiments of the present invention, the rare earth metal ions are selected from one or more of lanthanum (La) ions, cerium (Ce) ions, praseodymium (Pr) ions, neodymium (Nd) ions, samarium (Sm) ions, europium (Eu) ions, gadolinium (Gd) ions, terbium (Tb) ions, dysprosium (Dy) ions, holmium (Ho) ions, erbium (Er) ions, thulium (Tm) ions, ytterbium (Yb) ions, lutetium (Lu) ions, and yttrium (Y) ions; preferably selected from one or more of thulium (Tm) ions, ytterbium (Yb) ions, and lutetium (Lu) ions.

[0054] In some embodiments of the present invention, the concentration of the metal ions in the feed solution is ≥0.01 ppm; preferably, ≥0.1 mol / L.

[0055] In some embodiments of the present invention, the feed solution further comprises one or more of lithium ions, sodium ions, potassium ions, magnesium ions, calcium ions, strontium ions, and barium ions.

[0056] In some embodiments of the present invention, the feed solution further comprises an inorganic acid, preferably hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid; for example, hydrochloric acid.

[0057] In some embodiments of the present invention, when the extracted metal ions are gallium ions and / or indium ions, the pH of the feed solution is 0.5 to 8; preferably 1 to 6.

[0058] In some embodiments of the present invention, when the extracted metal ions are selected from one or more of nickel ions, cobalt ions and copper ions, the pH of the feed solution is 5 to 8; preferably 6 to 8.

[0059] In some embodiments of the present invention, when the extracted metal ions are selected from one or more rare earth metal ions, the pH of the feed solution is 0.5 to 3; for example, 1.

[0060] In some embodiments of the present invention, the extraction temperature is 20-80°C, preferably 30-40°C, for example 20-30°C.

[0061] In some embodiments of the present invention, the extraction time is 2-30 minutes, preferably 5-8 minutes, and more preferably 10-30 minutes.

[0062] In some embodiments of the present invention, the method for extracting metal ions further includes the following steps: mixing an organic phase containing metal ions with an aqueous solution of acid to obtain an aqueous phase containing metal ions and a regenerated organic phase.

[0063] The regenerated organic phase can be used as the extractant composition to extract the feed solution containing metal ions for recycling, or it can be further mixed and back-extracted with the aqueous solution of the acid.

[0064] In some embodiments of the present invention, during the back-extraction, the volume ratio of the organic phase containing metal ions to the aqueous solution of the acid is 1:(1~5); preferably 1:(1~2); for example, 1:1.

[0065] In some embodiments of the present invention, in the back-extraction, the aqueous solution of the acid is hydrochloric acid, nitric acid, sulfuric acid, or phosphoric acid; preferably hydrochloric acid.

[0066] In some embodiments of the present invention, during the back-extraction, the concentration of the acid in the aqueous solution is 0.1~3 mol / L; preferably 0.5~2 mol / L; for example, 0.5~1 mol / L.

[0067] In some embodiments of the present invention, the back-extraction temperature is 20-80°C, preferably 30-40°C, for example 20-30°C.

[0068] In some embodiments of the present invention, the back-extraction time is 2-30 minutes, preferably 5-8 minutes; more preferably 10-30 minutes; for example, 10 minutes, 20 minutes or 30 minutes.

[0069] The present invention also provides the application of the above-mentioned phosphoryl compounds or the above-mentioned extractant compositions as extractants.

[0070] In the aforementioned application, the extractant can be used to extract metal ions in hydrometallurgy; the metal ions are selected from one or more of lanthanum ions, cerium ions, praseodymium ions, neodymium ions, samarium ions, europium ions, gadolinium ions, terbium ions, dysprosium ions, holmium ions, erbium ions, thulium ions, ytterbium ions, lutetium ions, and yttrium ions, preferably selected from one or more of thulium ions, ytterbium ions, and lutetium ions; or, the metal ions are selected from one or more of gallium ions, indium ions, nickel ions, cobalt ions, and copper ions. The metal ions may originate from the waste residue of discarded technological products.

[0071] In the aforementioned application, the method for extracting metal ions is as described above.

[0072] In this invention, the above-mentioned phosphoryl compounds or the above-mentioned extractant compositions can be used for multi-stage extraction.

[0073] In some embodiments of the present invention, the number of extraction stages in the multi-stage extraction is 1-100; preferably 30-60.

[0074] In some embodiments of the present invention, the number of back-extraction stages in the multi-stage extraction is 1-50; preferably 10-30.

[0075] In some embodiments of the present invention, in the multi-stage extraction, the extractant composition is preferably added from the first stage; the feed solution is preferably added from the first to the 100th stages; and the aqueous solution of the acid is preferably added from the second to the 100th stages.

[0076] In this invention, a solution containing metal ions with a purity of 99.99% can be obtained through multi-stage extraction. After crystallization and evaporation, the corresponding metal salt can be obtained.

[0077] The positive and progressive effects of this invention are as follows:

[0078] The phosphoryl compounds prepared according to the present invention can achieve a purity of over 90%, and the raw materials used in the present invention, namely the compounds shown in Formula II, have already been industrially produced in several forms, making the raw materials of the present invention widely available and inexpensive.

[0079] The phosphoryl compounds prepared according to the present invention are stable as extractants, and are not prone to side reactions that would reduce the extractant concentration during use; they exhibit good extraction properties and no emulsification occurs; they have advantages such as simple synthesis, low cost, and good selectivity for metal ions.

[0080] The extractant provided by this invention exhibits good selectivity in separating thulium, ytterbium, and lutetium elements.

[0081] The extractant provided by this invention has a high extraction rate for gallium, indium, nickel, cobalt and copper.

[0082] Using the extractant described in this invention can reduce the cost of the extraction process, reduce pollution caused by the extraction process, and obtain products with high yield and high purity. Attached Figure Description

[0083] Figure 1 Gallium extraction rate at different pH values ​​in Example 5

[0084] Figure 2 Indium extraction rate at different pH values ​​in Example 5

[0085] Figure 3 Nickel extraction rate at different pH values ​​in Example 6

[0086] Figure 4 Cobalt extraction rate at different pH values ​​in Example 6

[0087] Figure 5 The copper extraction rate at different pH values ​​in Example 6

[0088] Figure 6 Cyclic loading diagram of the extractant in Example 1

[0089] Figure 7 The cyclic loading diagram of the extractant in Example 2.

[0090] Figure 8 The cyclic loading diagram of the extractant in Example 3. Detailed Implementation

[0091] The following provides clearer and more complete embodiments based on the present invention to illustrate the performance of the extractant provided by the present invention. Obviously, the embodiments described in this invention are only a part of the embodiments, not all of them. Based on the embodiments mentioned in this invention, all other embodiments that can be obtained by those skilled in the art without creative effort are also within the scope of protection of this invention.

[0092] Example 1: Synthesis of 2-(di(2-ethylhexyloxy))phosphoryloxyacetic acid

[0093] 25.79 g of di(2-ethylhexyl)phosphoric acid and 80 mL of tetrahydrofuran were added to a reaction vessel. Then, 3.36 g of 60% sodium hydride was added in several portions while stirring at room temperature. Next, 15.06 g of tert-butyl chloroacetate was added, and the mixture was heated to 90 °C for 8 hours. Afterward, the temperature was increased, and the solvent was distilled off to obtain a viscous, turbid liquid. 100 mL of dichloromethane and 100 mL of saturated brine were added, and the mixture was washed with shaking. After standing and phase separation, a dichloromethane solution containing the intermediate was obtained.

[0094] Then, 27.36 g of trifluoroacetic acid was added dropwise to the reaction vessel, and the mixture was heated at 40°C for 6 hours. After that, the temperature was increased, and the solvent and trifluoroacetic acid were distilled off to obtain a viscous liquid. 100 mL of ethyl acetate and 100 mL of saturated brine were added, the mixture was shaken and washed, allowed to stand for phase separation, and finally the ethyl acetate phase was evaporated to dryness to obtain 2-(di(2-ethylhexyloxy))phosphoryloxyacetic acid as shown in Formula III.

[0095] 2-(Di(2-ethylhexyloxy))phosphoryloxyacetic acid: 1 H NMR (400MHz, CDCl3) δ: 9.97 (s,1H), 4.55 (d, J = 11.7 Hz, 2H), 4.01 (t, J = 2.1 Hz, 4H), 1.69 – 1.49 (m,2H), 1.43 – 1.20 (m, 16H), 0.86 (t, J = 7.3 Hz, 12H); 31 P NMR (162MHz, CDCl3)δ: -1.10 (s).

[0096] .

[0097] Example 2: Synthesis of 2-((2-ethylhexyl)(2-ethylhexyloxy))phosphooxyacetic acid

[0098] 24.48 g of 2-ethylhexyl phosphate mono(2-ethylhexyl) ester and 80 mL of cyclopentyl methyl ether were added to a reaction vessel. 3.84 g of sodium hydroxide was added in several portions while stirring at room temperature. Then, 23.40 g of tert-butyl bromoacetate was added, and the mixture was heated to 80 °C for 8 hours. Afterward, the temperature was increased, and the solvent was distilled off to obtain a viscous, turbid liquid. 100 mL of 1,2-dichloroethane and 100 mL of saturated brine were added, and the mixture was washed by shaking. After standing and phase separation, a 1,2-dichloroethane solution containing the intermediate was obtained.

[0099] Then, 27.36 g of trifluoroacetic acid was added dropwise to the reaction vessel, and the mixture was heated at 40°C for 6 hours. After that, the temperature was increased, and the solvent and trifluoroacetic acid were distilled off to obtain a viscous liquid. 100 mL of ethyl acetate and 100 mL of saturated brine were added, the mixture was shaken and washed, allowed to stand for phase separation, and finally the ethyl acetate phase was evaporated to dryness to obtain 2-((2-ethylhexyl)(2-ethylhexyloxy))phosphooxyacetic acid as shown in Formula IV.

[0100] 2-((2-ethylhexyl)(2-ethylhexyloxy))phosphooxyacetic acid: 1 H NMR (400MHz, CDCl3) δ:10.81 (s, 1H), 4.77 – 4.38 (m, 2H), 4.11 – 3.93 (m, 2H), 1.86 (d, J = 20.8,4.8 Hz, 2H), 1.80 – 1.66 (m, 2H), 1.64 – 1.05 (m, 16H), 1.04 – 0.71 (m, 12H); 31 P NMR (162MHz, CDCl3) δ:35.57 (s).

[0101] .

[0102] Example 3: Synthesis of 2-(bis(2,4,4-trimethylpentyl))phosphoryloxyacetic acid

[0103] 23.20 g of bis(2,4,4-trimethylpentyl)phosphoryloxyacetic acid and 80 mL of tert-butyl methyl ether were added to a reaction vessel. 6.53 g of sodium ethoxide was added in several portions while stirring continuously at room temperature. Then, 23.40 g of tert-butyl bromoacetate was added, and the mixture was heated to 80 °C for 8 hours. Afterward, the temperature was increased, and the solvent was distilled off to obtain a viscous, turbid liquid. 100 mL of dichloromethane and 100 mL of saturated brine were added, and the mixture was washed with shaking. After standing and phase separation, a dichloromethane solution containing the intermediate was obtained.

[0104] Then, 27.36 g of trifluoroacetic acid was added dropwise to the reaction vessel, and the mixture was heated at 40°C for 6 hours. After that, the temperature was increased, and the solvent and trifluoroacetic acid were distilled off to obtain a viscous liquid. 100 mL of ethyl acetate and 100 mL of saturated brine were added, the mixture was shaken and washed, allowed to stand for phase separation, and finally the ethyl acetate phase was evaporated to dryness to obtain 2-(bis(2,4,4-trimethylpentyl))phosphoryloxyacetic acid as shown in Formula V.

[0105] 2-(bis(2,4,4-trimethylpentyl))phosphoryloxyacetic acid: 1 H NMR (400MHz, CDCl3) δ: 11.67(s, 1H), 4.52 (dt, J = 11.5, 4.2 Hz, 2H), 2.08 – 1.97 (m, 2H), 1.95 – 1.62(m, 4H), 1.42 – 1.12 (m, 4H), 1.08 (d, J = 6.6 Hz, 6H), 0.89 (s, 18H). 31 P NMR (162MHz, CDCl3) δ: 63.88 – 63.57 (m).

[0106] .

[0107] All the following examples are assumed to be conducted at room temperature (20-30°C).

[0108] Example 4

[0109] The three extractants prepared according to Examples 1, 2, and 3 were diluted with dodecane at a volume ratio of 1:4 to obtain the organic phase for extraction.

[0110] Prepare a hydrochloric acid solution containing 50 mg / L of 15 rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y) and adjust the pH to 1.

[0111] The organic phase and rare earth feed solution were mixed at a volume ratio of 1:1 and extracted by shaking for 30 minutes. After extraction, the organic phase and aqueous phase were separated. The rare earth element content in the aqueous phase was determined by ICP-OES method. Specifically, the test can be performed according to GB / T18114.8-2010 "Chemical Analysis Methods for Rare Earth Concentrates - Part 8: Determination of the Composition of Fifteen Rare Earth Element Oxides". Based on the test results, the separation coefficients of the three extractants were calculated. The calculation results are shown in Table 1.

[0112] Table 1. Separation coefficients of extractants

[0113]

[0114] As shown in Table 1, all three extractants can be used to separate thulium, ytterbium, and lutetium from rare earth elements.

[0115] The extracted organic phase is back-extracted with 0.5M hydrochloric acid at a 1:1 ratio for 30 minutes to obtain an aqueous phase containing thulium, ytterbium, and lutetium, thereby achieving the separation of thulium, ytterbium, and lutetium from other rare earth elements. The back-extracted organic phase can be used again to extract thulium, ytterbium, and lutetium from the feed solution.

[0116] Similar separation effects can be achieved by controlling the pH value between 0.5 and 3.

[0117] Example 5

[0118] The extractant in Example 1 was diluted with dodecane at a volume ratio of 1:3 to obtain the organic phase for extraction.

[0119] A series of feed solutions containing 0.1 M gallium and indium at different pH values ​​were prepared and extracted with an organic phase at a 1:1 ratio using shaking for 30 minutes. After extraction, the organic phase and aqueous phase were separated. The gallium and indium content in the aqueous phase was determined using ICP-OES. Based on the measured data, the extraction rates of gallium and indium at different pH values ​​were calculated (see details). Figure 1 and Figure 2 ).

[0120] The figure shows that the extractant has extremely high extraction rates for gallium and indium between pH 1 and 6, and can be used to extract gallium and indium.

[0121] The organic phase loaded with gallium and indium can be back-extracted for 20 minutes with 1M hydrochloric acid at a 1:1 ratio. The back-extracted organic phase can still be used for extraction.

[0122] Example 6

[0123] The extractant in Example 2 was diluted with dodecane at a volume ratio of 1:4 to obtain the organic phase for extraction.

[0124] A series of feed solutions containing 0.1M nickel, cobalt, and copper at different pH values ​​were prepared. These solutions were then mixed with the organic phase at a 1:1 ratio and extracted with shaking for 30 minutes. After extraction, the organic and aqueous phases were separated. The nickel, cobalt, and copper content in the aqueous phase was determined using ICP-OES. Based on the measured data, the extraction rates of nickel, cobalt, and copper at different pH values ​​were calculated (see details). Figure 3 , Figure 4 and Figure 5 ).

[0125] The graph shows that the extractant has extremely high extraction rates for nickel, cobalt, and copper after pH 6, and can be used to extract nickel, cobalt, and copper.

[0126] Organic phases loaded with nickel, cobalt, and copper can be back-extracted for 10 minutes using 0.5M hydrochloric acid at a 1:1 ratio. The back-extracted organic phase can still be used for extraction.

[0127] Example 7

[0128] The extractant in Example 1 was diluted with dodecane at a volume ratio of 1:4 to obtain an organic phase for extraction, which was used to extract a small amount of rare earth ions from calcium chloride solution. The impurity content in calcium chloride is shown in Table 2.

[0129] Table 2. Impurity content in calcium chloride before extraction

[0130]

[0131] The pH of the calcium chloride solution was adjusted to around 4 using hydrochloric acid. The ratio of calcium chloride solution to extractant was 1:1. The extraction was performed three times, each time for 30 minutes, to obtain a purified calcium chloride solution. The impurity content in the calcium chloride solution at this time is shown in Table 3.

[0132] Table 3. Impurity content in purified calcium chloride

[0133]

[0134] As can be seen from the comparison of Tables 2 and 3, the extractant in Example 1 can extract rare earth ion impurities in calcium chloride to below the detection line. Then, a 0.5M hydrochloric acid solution with a ratio of 1:1 and a back-extraction time of 20 minutes can be used to back-extract the rare earth ions in the extractant. The organic phase after back-extraction can still be used for extraction.

[0135] Example 8

[0136] The three extractants mentioned in Examples 1, 2, and 3 were prepared into extractant solutions with dodecane at a volume ratio of 1:4. Then, a 0.1M TmCl3 solution was prepared, and the pH was adjusted to 1 using hydrochloric acid.

[0137] The extractant solution and TmCl3 solution were mixed at a ratio of 1:2 and shaken for 30 min to obtain the loaded rare earth extractant. The aqueous and organic phases were then separated. 0.5 M hydrochloric acid was added to the organic phase at a volume ratio of 1:1, and back-extracted for 30 min. This back-extraction was repeated three times, constituting one cycle.

[0138] After ten cycles, no emulsification occurred during extraction, indicating good extraction performance. The aqueous phase from each cycle was collected, and the rare earth element content in the aqueous phase was determined using ICP-OES. The measured data were then processed and calculated to obtain the cyclic loading diagrams for the three extractants. (See details...) Figure 6 , 7 8)

[0139] As shown in the figure, the extraction performance of the three extractants did not decrease significantly after 10 cycles, indicating that the three extractants have good stability and can be recycled.

[0140] Finally, the extractant and diluent mentioned in this invention are mixed at a volume ratio of 1:(1-20) to obtain a product for extracting metallic elements such as thulium, ytterbium, lutetium, gallium, indium, nickel, cobalt, and copper.

[0141] Compared with existing technologies, the extractant provided by this invention exhibits good selectivity in separating thulium, ytterbium, and lutetium, and high extraction rates for gallium, indium, nickel, cobalt, and copper. The extractant has a stable structure, can be recycled multiple times, and is not prone to decomposition; the back-extraction acidity during recycling is low, reducing pollution; no emulsification occurs during extraction, resulting in excellent extraction performance; and the extractant is easy to synthesize and inexpensive.

[0142] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A phosphoryl compound, which is a compound of formula I or a salt thereof: ， in, R1 and R2 are independently selected from C6-C 15 Alkyl, C6-C 15 Alkoxy groups and C6-C substituted with one or more C1-C6 alkyl groups 10 Aryl; n is an integer selected from 1 to 6.

2. The phosphoryl compound according to claim 1, characterized in that, It meets one or more of the following conditions: (1) In R1 and R2, the C6-C 15 Alkyl groups are C6-C 10 Alkyl group, preferably a C8-C9 straight-chain or branched alkyl group; more preferably 2-ethylhexyl, 2,4,4-trimethylpentyl, 2,2,4-trimethylpentyl or 2,6-dimethylheptyl; (2) In R1 and R2, the C6-C 15 The alkoxy group is C6-C. 10 Alkyl group; preferably C8-C9 straight-chain or branched alkoxy group; for example, 2-ethylhexyloxy group; (3) In R1 and R2, the C6-C alkyl group substituted with one or more C1-C6 alkyl groups 10 The C1-C6 alkyl group in the aryl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, or tert-butyl; (4) In R1 and R2, the C6-C alkyl group substituted with one or more C1-C6 alkyl groups 10 C6-C in aryl 10 The aryl group is either phenyl or naphthyl.

3. The phosphoryl compound according to claim 1, characterized in that, It meets one or two of the following conditions: (1) n is 1 or 2; (2) R1 and R2 are independently selected from 2-ethylhexyl, 2,4,4-trimethylpentyl and 2-ethylhexyloxy; Preferably, the compound represented by Formula I is a compound represented by Formula III, Formula IV or Formula V: 、 、 。 4. An extractant composition, characterized in that, It includes the phosphoryl compounds as described in any one of claims 1-3, and a diluent.

5. The extractant composition according to claim 4, characterized in that, It meets one or more of the following conditions: (1) The diluent is one or more of kerosene, heptane, octane and dodecane; for example, dodecane; (2) The volume ratio of the phosphoryl compound to the diluent is 1:(1~20); preferably 1:(1~5); for example 1:3 or 1:4; (3) The molar volume ratio of the phosphoryl compound to the diluent is 0.01~2 mol / L; preferably 0.1~2 mol / L.

6. A method for preparing a compound of formula I as described in any one of claims 1-3, characterized in that, It includes the following steps: Step 1: In a solvent and in the presence of a base, the compound shown in Formula II undergoes a substitution reaction with a halocarboxylic acid ester to obtain a reaction intermediate. Step 2: In a solvent, in the presence of an acid or a base, the reaction intermediate undergoes a hydrolysis reaction to obtain the compound shown in Formula I. ， Wherein, R1 and R2 are as described in any one of claims 1-3.

7. A method for extracting metal ions, characterized in that, It includes the following steps: The extractant composition as described in claim 4 or 5 is used to extract a liquid containing metal ions to obtain an organic phase containing metal ions. The metal ions are selected from one or more of rare earth metal ions, gallium ions, indium ions, nickel ions, cobalt ions, and copper ions.

8. The method for extracting metal ions according to claim 7, characterized in that, It meets one or more of the following conditions: (1) In the extraction, the volume ratio of the extractant composition to the liquid is 1:(1~3); for example, 1:1 or 1:2; (2) In the feed solution, the concentration of the metal ions is ≥0.01 ppm; preferably ≥0.1 mol / L; (3) The liquid also contains one or more of lithium ions, sodium ions, potassium ions, magnesium ions, calcium ions, strontium ions and barium ions; (4) The liquid also contains inorganic acid, preferably hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid; for example, hydrochloric acid; (5) The rare earth metal ions are selected from one or more of lanthanum ions, cerium ions, praseodymium ions, neodymium ions, samarium ions, europium ions, gadolinium ions, terbium ions, dysprosium ions, holmium ions, erbium ions, thulium ions, ytterbium ions, lutetium ions, and yttrium ions; preferably selected from one or more of thulium ions, ytterbium ions, and lutetium ions. (6) When the extracted metal ions are gallium ions and / or indium ions, the pH of the feed solution is 0.5~8; preferably 1~6; When the extracted metal ions are selected from one or more of nickel ions, cobalt ions, and copper ions, the pH of the feed solution is 5-8; preferably 6-8. When the extracted metal ions are selected from one or more rare earth metal ions, the pH of the feed solution is 0.5~3; for example, 1. (7) The extraction temperature is 20-80℃; preferably 20-30℃; (8) The extraction time is 2-30 minutes; preferably 10-30 minutes.

9. The method for extracting metal ions according to claim 7, characterized in that, The method for extracting metal ions further includes the following steps: back-extracting the organic phase containing metal ions with an aqueous solution of acid to obtain an aqueous phase containing metal ions and a regenerated organic phase. Preferably, it satisfies one or more of the following conditions: (1) In the back-extraction, the volume ratio of the organic phase containing metal ions to the aqueous solution of the acid is 1:(1~5); preferably 1:(1~2); for example 1:1; (2) In the aqueous solution of the acid, the acid is hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid; preferably hydrochloric acid; (3) In the aqueous solution of the acid, the concentration of the acid is 0.1~3 mol / L; preferably 0.5~2 mol / L; for example 0.5~1 mol / L; (4) The back-extraction temperature is 20-80℃; preferably 20-30℃; (5) The back-extraction time is 2-30 minutes; preferably 10-30 minutes.

10. The use of a phosphoryl compound as described in any one of claims 1-3, or an extractant composition as described in claim 4 or 5, as an extractant; Preferably, in the aforementioned application, the extractant is used to extract metal ions in hydrometallurgy; the metal ions are selected from one or more of lanthanum ions, cerium ions, praseodymium ions, neodymium ions, samarium ions, europium ions, gadolinium ions, terbium ions, dysprosium ions, holmium ions, erbium ions, thulium ions, ytterbium ions, lutetium ions, and yttrium ions, preferably selected from one or more of thulium ions, ytterbium ions, and lutetium ions; or, the metal ions are selected from one or more of gallium ions, indium ions, nickel ions, cobalt ions, and copper ions.

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