CN107447109B

CN107447109B - Extraction composition, extraction system, extraction method and back extraction method

Info

Publication number: CN107447109B
Application number: CN201610383005.6A
Authority: CN
Inventors: 袁承业; 李晋锋
Original assignee: Shanghai Institute of Organic Chemistry of CAS
Current assignee: Shanghai Institute of Organic Chemistry of CAS
Priority date: 2016-06-01
Filing date: 2016-06-01
Publication date: 2020-08-07
Anticipated expiration: 2036-06-01
Also published as: CN107447109A

Abstract

The invention discloses an extraction composition, an extraction system, an extraction method and a back extraction method. The extraction composition of the present invention comprises: an extractant and a neutral phosphorus-oxygen compound; the extractant includes N, N-di (2-ethylhexyl) acetamide and N, N-dihexylacetamide. The extraction composition disclosed by the invention has the advantages of good acid-base stability, small water phase solubility, small density and viscosity, no need of complex extraction operation, low corrosion to equipment and suitability for industrial operation requirements.

Description

Extraction composition, extraction system, extraction method and back extraction method

Technical Field

The invention relates to an extraction composition, an extraction system, an extraction method and a back extraction method.

Background

Lithium has important applications not only in the defense industry, but also in the national economy, and in particular in the energy field:⁶l i and⁷l i are important materials for fuel and nuclear fission reaction of nuclear fusion reactor in the future, and the demand for battery materials is increasing, therefore, lithium is called energy metal in 21 st century.

Salt lake brine is an important resource of lithium. China has rich lithium resources in salt lake brine, and the storage quantity of the lithium resources is in the forefront of the world. However, since brine contains many kinds of metal ions, the comprehensive utilization thereof and the technology of separating and extracting lithium from brine are important problems to be studied, and particularly, the technology of separating and extracting lithium from brine containing high-concentration magnesium and low-concentration lithium, namely, high magnesium-lithium ratio, is a recognized worldwide technical problem.

The solvent extraction technology is an effective technology for separating and extracting various metals from a solution, has the advantages of high separation efficiency, simple process and equipment, continuous operation, easy realization of automatic control and the like, and is considered to be one of the most promising methods for extracting and separating lithium from brine with a high magnesium-lithium ratio. Since the mid-sixties of the last century, several extraction systems and processes have been proposed at home and abroad. In 1967, Nelli J.R. et al invented an extraction system and process [1.Nelli J.R. et al.Fr.1,535,818 (1967); U.S. Pat. No. 3,537,813(1970).]: adding FeCl into brine₃As a co-extractant, 80% diisobutyl ketone-20% tributyl phosphate (TBP) is used as an organic phase, L i and Fe are mixed with L iFeCl₄Formal co-extraction into the organic phase, with a large amount of MgCl in the aqueous phase₂And other metalsThis system, although highly selective for extraction of L i, produced L iCl and FeCl by back-extraction with water₃The mixed solution needs to be extracted and separated again L i and Fe by a di (2-ethylhexyl) phosphoric acid-tributyl phosphate system, so that the process is long and complicated to operate, the application of the mixed solution in industrial production is not seen so far, in 1979, the research institute of Qinghai salt lake of Chinese academy proposes a system and a process for extracting lithium by using kerosene solution of single extracting agent tributyl phosphate, so that the extraction system is simplified, semi-industrial tests for extracting lithium from brine of Dachadan salt lake are carried out in 1984, and Chinese patent of invention [3. Huangshi Qiang et al, Chinese patent of invention, 87103431]And authorization is obtained. However, the tributyl phosphate in the system has high concentration and strong corrosivity to extraction equipment, and the extraction agent is not only dissolved and lost in water in long-term operation, but also degraded in an acidic medium, and particularly the severe swelling effect of the tributyl phosphate on materials for manufacturing the extraction equipment limits the industrial large-scale application of the tributyl phosphate.

The Chinese invention patent (CN103055539A) discloses a method for extracting lithium by using an amide compound or a mixture of the amide compound and a neutral phosphorus-oxygen compound as an extracting agent, ferric trichloride as a co-extracting agent and aliphatic hydrocarbon or aromatic hydrocarbon as a diluting agent. However, with respect to the specific method disclosed by the method, the problems are still solved in the industrial process, such as low single-stage extraction rate, influence on yield and yield, and the extraction stages are increased for obtaining high yield; the separation factor of lithium from magnesium, sodium and potassium is not large enough, the directly obtained product cannot meet the requirement of high purity, and the washing grade number or other post-treatment modes must be increased.

Disclosure of Invention

The invention aims to solve the problems that the existing extracting agent for extracting lithium from lithium-containing brine has serious corrosion to equipment, large solvent loss of the extracting agent, low single-stage extraction rate, low yield, long product purification process and the like, and provides an extracting composition, an extracting system, an extracting method and a back-extracting method. The extraction composition disclosed by the invention has the advantages of good acid-base stability, small aqueous phase solubility, small density and viscosity, high lithium extraction rate and back extraction rate, large separation factor of lithium, sodium, potassium and magnesium, small corrosion to equipment and suitability for industrial operation requirements.

The present invention provides an extraction composition comprising: an extractant and a neutral phosphorus-oxygen compound; the extractant comprises: n, N-di (2-ethylhexyl) acetamide and N, N-dihexylacetamide;

the general structure of the neutral phosphorus-oxygen compound is as follows (formula A):

wherein R is¹And R²Independently is a straight chain or C with a branched chain₁-C₁₂Alkyl, straight-chain or branched C₁-C₁₂Alkoxy, thienyl, pyridyl, naphthyl, substituted or unsubstituted phenyl, or substituted or unsubstituted phenoxy;

when said phenyl is substituted, the substituents are selected from one or more of: halogen, C₁-C₆Alkyl, hydroxy, C₁-C₆Alkoxy, trifluoromethyl, trifluoromethoxy, phenoxy, piperidinyl, morpholinyl, pyrrolyl, tetrahydropyrrolyl, nitro, amino; when the phenyl group has a plurality of substituents, the substituents may be the same or different;

when said phenoxy group is substituted, the substituents are selected from one or more of: halogen, C₁-C₆Alkyl, hydroxy, C₁-C₆Alkoxy, trifluoromethyl, trifluoromethoxy, phenoxy, piperidinyl, morpholinyl, pyrrolyl, tetrahydropyrrolyl, nitro, amino; when the number of the substituents on the phenoxy group is plural, the substituents may be the same or different.

In the neutral phosphorus-oxygen compound, the"straight chain or branched C of (1)₁-C₁₂Alkyl is "preferably" straight-chain or branched C₁-C₈Alkyl ", more preferably" straight-chain or branched C₄-C₈Alkyl groups ". Said "straight or branched C₁-C₈Alkyl "is preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 1-methyl-heptyl or 2-ethyl-hexyl.

In the neutral phosphorus-oxygen compound, the' straight chain or branched chain C₁-C₁₂Alkoxy is "preferably" straight-chain or branched C₁-C₈Alkoxy ", more preferably" straight-chain or branched C₄-C₈Alkoxy ". Said "straight or branched C₁-C₈Alkoxy "is preferably methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, 1-methyl-heptyloxy or 2-ethyl-hexyloxy.

The neutral phosphorus-oxygen compound shown in the formula A is preferably one or more of the following compounds:

in the extraction composition, the volume ratio of the extraction agent to the neutral phosphorus-oxygen compound is preferably 7: 1-1: 8, more preferably 5:1-1:5, even more preferably 5:3-1:2, most preferably 2:1-1:1, and even more preferably 3: 2.

In the extractant, the volume ratio of the N, N-di (2-ethylhexyl) acetamide to the N, N-dihexylacetamide is preferably 10:1 to 1:10, more preferably 5:1 to 1:6, and most preferably 3:1 to 1:2.5 (for example, 2:1 to 1:2, 1: 1).

The extractant can also comprise other amide compounds, and the other amide compounds are preferably one or more of N, N-dihexylpropionamide, N-dihexyl-2-methylpropionamide, N-dihexylbenzamide, N-dihexylp-methylbenzamide and N, N-dihexyln-butylamide:

when the extractant contains other amide compounds, the dosage of the other amide compounds has no special requirement as long as the extraction and back-extraction performance of the extractant is not influenced. When other amide compounds are contained in the extracting agent, the content of the N, N-di (2-ethylhexyl) acetamide and the N, N-dihexylacetamide in the extracting agent is preferably 0.01-99.9%, more preferably 70-85.6%, and most preferably 75-80%. When other amide compounds are contained in the extractant, the volume ratio of the total volume of the N, N-di (2-ethylhexyl) acetamide and the N, N-dihexylacetamide to the volume of the other amide compounds is preferably 7:3-6.02:1, and preferably 3:1-4: 1.

The extraction composition preferably further comprises a diluent, which may be a diluent conventional in the art. The diluent is preferably an aliphatic hydrocarbon (for example dodecane) or an aromatic hydrocarbon having a boiling point of 100 ℃ or higher at normal pressure, and may also be kerosene. The amount of said diluent is preferably from 10% to 80%, more preferably from 20% to 60%, most preferably from 30% to 40%, the percentages being volume percentages of the diluent relative to the total volume of the extraction composition.

The extraction composition preferably further comprises a co-extractant, and the co-extractant can be dissolved in the aqueous phase firstly or can be stabilized in the organic phase firstly during extraction. The co-extractant generally refers to ferric salt capable of obviously improving the extraction rate of lithium, and can be ferric chloride, ferric sulfate, ferric nitrate and/or ferric phosphate and the like, and ferric chloride is preferred. The dosage of the co-extraction agent can be determined according to the content of lithium ions in the substance to be extracted, and the molar ratio of ferric ions in the co-extraction agent to lithium ions in the substance to be extracted is preferably 1:1.75-2:1, more preferably 1.3:1-1.75:1, more preferably 1:1-1.5:1, and even more preferably 1.1: 1. The material to be extracted is preferably lithium-containing brine.

When the extraction composition comprises other components in addition to the extractant and neutral phosphorus oxygen species, the total content of the extractant and neutral phosphorus oxygen species in the organic phase of the extraction composition is preferably from 20% to 90%, more preferably from 40% to 80%, most preferably from 60% to 70% (volume percent).

The extractant can be composed of N, N-di (2-ethylhexyl) acetamide and N, N-dihexylacetamide. The extractant can also be composed of N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide and one or more of N, N-dihexylpropionamide, N-dihexyl-2-methylpropionamide, N-dihexylbenzamide, N-dihexyl-p-methylbenzamide and N, N-dihexyl-N-butylamide.

The extraction composition further preferably comprises the extractant, the neutral phosphorus oxygen compound shown in the formula A and the diluent.

The extraction composition more preferably consists of the extractant, the neutral phosphorus oxygen compound shown in the formula A, the diluent and the co-extractant.

The invention also provides an extraction system comprising the extraction composition and a lithium-containing brine.

In the extraction system, the lithium-containing brine can be conventional lithium-containing brine in the field, and the invention preferably selects the lithium-containing brine with high magnesium-lithium ratio, wherein the high magnesium-lithium ratio generally refers to Mg in the lithium-containing brine²⁺/Li⁺The molar ratio of (2) to (30), preferably (16), the lithium-containing brine can contain L i in an amount of 0.02 mol/L-2.0 mol/L⁺2.0 mol/L-5.0 mol/L of Mg²⁺0 mol/L-0.5 mol/L of Na⁺K of 0 mol/L-0.5 mol/L⁺And Cl of not less than 6 mol/L^-0 mol/L-0.90 mol/L of B₂O₃And 0.001 mol/L-0.5 mol/L of H⁺The lithium-containing brine preferably comprises L i of 0.144 mol/L-2.0 mol/L⁺4 mol/L-4.64 mol/L of Mg²⁺0.05 mol/L-0.4 mol/L of Na⁺K of 0.02 mol/L-0.4 mol/L⁺9.2 to 10.7 mol/L of Cl^-0 mol/L-0.1 mol/L of B₂O₃And 0.04 mol/L-0.3 mol/L of H⁺(halogen)Water acidity) the lithium-containing brine more preferably comprises L i of 0.29 mol/L-2.0 mol/L⁺4 mol/L-4.32 mol/L of Mg²⁺0.05 mol/L-0.1 mol/L of Na⁺K of 0.02 mol/L-0.4 mol/L⁺9.8-10.7 mol/L Cl^-0 mol/L-0.01 mol/L of B₂O₃And 0.04 mol/L-0.05 mol/L of H⁺(acidity of brine).

In the extraction system, the volume ratio of the organic phase (organic phase) to the lithium-containing brine (aqueous phase) of the extraction composition is preferably 1:5 to 10:1, more preferably 1:2 to 6:1, most preferably 5:1 to 1:1, and even more preferably 2: 1.

In the extraction system, if the extraction composition contains a co-extraction agent, the concentration of the co-extraction agent in the lithium-containing brine is preferably 0.05 mol/L-3.5 mol/L.

The invention also provides an extraction method, which comprises the following steps: the extraction composition is used for extracting lithium-containing brine.

The extraction method may be a method for extracting lithium, which is conventional in the art, and preferably comprises the following steps: mixing organic phase containing diluent, said extractant and neutral phosphorus-oxygen compound with lithium-containing bittern containing co-extractant, oscillating or stirring for balancing, and standing for layering. Wherein mass transfer is by shaking or stirring.

In the extraction method, the temperature of the organic phase and the aqueous phase is preferably 10-50 ℃ (preferably 20-40 ℃, more preferably 25-30 ℃), i.e. the extraction is carried out at 10-50 ℃.

The extraction method can also finish the mass transfer and phase separation processes by means of extraction equipment such as a centrifugal extractor, a mixing and clarifying tank, an extraction tower and the like. The centrifugal extractor, the mixer-settler and the extraction tower can be conventional extraction equipment in the field, and the using conditions and the method can refer to the conventional using conditions and the method for extracting lithium from the lithium-containing aqueous solution.

The invention also provides a back extraction method, which comprises the following steps: mixing the lithium-containing organic phase obtained by the extraction method with an aqueous solution of acid, oscillating or stirring for balancing, and standing for layering. Wherein the lithium carried by the organic phase is transferred to the aqueous phase.

In the stripping method, the molar concentration of the aqueous acid solution is preferably 0.5 mol/L-12 mol/L, more preferably 4-10 mol/L, and most preferably 6-8 mol/L, wherein the molar concentration refers to the ratio of the amount of the substance of the acid to the total volume of the aqueous acid solution.

In the stripping process, the acid in the aqueous acid solution may be an acid conventional in the art, and is preferably an inorganic acid. The inorganic acid is preferably one or more of hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid, and more preferably hydrochloric acid.

In the stripping process, the volume ratio of the lithium-containing organic phase to the aqueous acid solution may be a volume ratio conventional in the art, such as 1:1 to 50:1, preferably 5:1 to 40:1, and more preferably 10:1 to 30: 1.

The stripping process is preferably carried out at a temperature of from 10 to 50 deg.C, more preferably from 24 to 25 deg.C.

In the present invention, the ratio of the organic phase to the aqueous phase refers to the volume ratio of the organic phase to the aqueous phase without containing the co-extractant.

In the invention, the normal pressure refers to 1 atmosphere and 101.325 kPa.

The above preferred conditions can be arbitrarily combined to obtain preferred embodiments of the present invention without departing from the common general knowledge in the art.

The reagents and starting materials used in the present invention are commercially available.

The positive progress effects of the invention are as follows: the extractant has good acid-base stability, and the water solubility, density and viscosity are small, so that the loss in the extraction process is reduced, the purity of the extracted lithium is improved, and the defects that the existing extractant for extracting lithium from lithium-containing brine has serious corrosion to equipment, large solvent loss of the extractant and the like are overcome. The extraction composition, the extraction system and the extraction method have the advantages of high single-stage extraction rate and back extraction rate of lithium, large separation factor of lithium and sodium, potassium and magnesium, high yield, easy product purification and suitability for industrial operation requirements.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.

The parts referred to in the following examples are parts by volume.

Unless specifically defined, the terms referred to in the present invention are explained as follows:

1. compare

For a batch extraction process, the volume of organic phase extracted, V (m)³) And feed liquid water phase L (m)³) The ratio of the two is called the phase ratio; for a continuous extraction process, the extract phase volume flow rate V (m)³S) and liquid phase volume flow rate L (m)³The ratio/s), also referred to as phase ratio or two-phase flow ratio, is herein collectively referred to as O/A for two-phase volume or flow. Compared with the formula shown by R:

in the formula: v_oVolume of the extract phase, V_aIs the volume of the feed liquid phase

2. Extraction rate

The extraction rate is the percentage of the extracted material transferred from the feed liquid phase to the extraction phase in the extraction process to the total amount of the extracted material in the feed liquid phase, and represents the degree of extraction separation. The formula for calculating the extraction rate E (%) is:

in the formula: n is_aN is the amount of extracted material in the feed solution_oThe amount of extracted material in the raffinate.

3. Distribution ratio

The distribution ratio is also called the distribution coefficient. The partitioning behavior of extracted substance a in the two phases can be understood as the overall effect of a partitioning of a in the two phases in the various forms a1, a 2. In general, the experimentally determined values represent the total concentration of the various forms of extracted material present in each phase. The system partition coefficient is defined as the ratio of the total concentration of extracted substances in the extraction organic phase (O) to the total concentration in the feed liquid phase (A) under certain conditions when the system reaches equilibrium, and is represented by D:

the partition ratio represents the actual partition ratio of the extracted substances in the two phases after the extraction system reaches equilibrium and is generally determined experimentally. The larger the distribution ratio of the extracted substance is, the easier the substance is to be extracted, and the distribution ratio is related to the extraction conditions, such as the concentration and acidity of the extracted substance in the aqueous phase, other coexisting substances, the type and concentration of the extractant in the organic substance, the type of the diluent, the temperature during extraction, and the like.

4. Separation factor

When extraction separation is performed under certain conditions, the ratio of the extraction distribution ratio of two substances to be separated between two phases, which is called extraction separation factor, also called extraction separation coefficient, is usually represented by β, if A, B represents two substances to be separated respectively, there are:

in the formula: d_AIs the distribution ratio of A substance, D_BThe distribution ratio of the B substance is shown.

The extraction separation coefficient quantitatively shows the difficulty of separating two substances in a liquid phase of a certain extraction system, when the β value is 1, the two substances cannot be separated, and the larger or smaller the β value is, the better the separation effect is, namely, the higher the separation selectivity of the extractant is.

Example 1

The lithium-containing brine comprises the following components:

organic phase: kerosene is used as a diluent, and the content of compounds N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide and TBP in the kerosene solution is respectively 25%, 5% and 30% (the percentage of each component in the total volume of the organic phase);

taking 1 part of lithium-containing brine, adding FeC1₃As co-extraction agent, Fe in water phase³⁺/Li⁺Adding 2 parts of the organic phase (compared with extraction, the organic phase/water phase, namely O/A is 2:1), fully mixing the two phases at 25 ℃ for extraction, standing for layering after mixing, good phase separation effect, colorless water phase and clear interface of the two phases, and respectively measuring L i in the balanced water phase and the organic phase⁺、Na⁺、K⁺、Mg²⁺From the concentration, the extraction rate of L i was calculated to be 83.75%, L i⁺、Na⁺、K⁺And Mg²⁺The partition ratios of (A) are 2.577, 0.029, 0.036, 0.00621, L i/Mg, L i/Na and L i/K, respectively, and the separation coefficients are 415, 88.9 and 71.6, respectively.

Example 2

The lithium-containing brine comprises the following components:

organic phase: kerosene is used as a diluent, and the content of compounds N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide and TBP in the kerosene solution is respectively 25%, 25% and 30% (the percentage of each component in the total volume of the organic phase);

adding 1 part of lithium-containing brine into a one-liquid funnel, and adding FeC1₃As co-extraction agent, Fe in water phase³⁺/Li⁺Adding 1 part of the organic phase (compared with the O/A (1/1)) at a molar ratio of 1.1, fully mixing the two phases at 25 ℃ for extraction, standing for layering after mixing is finished, achieving good phase separation effect, colorless aqueous phase and clear interface of the two phases, and respectively measuring L i in a balanced aqueous phase and L i in an organic phase⁺、Na⁺、K⁺And Mg²⁺From this, the extraction rate of L i was calculated to be 86.44%, L i⁺、Na⁺、K⁺And Mg²⁺The partition ratios of (A) to (B) of 6.375, 0.067, 0.079, 0.0137, L i/Mg, L i/Na and L i/K have separation coefficients of 465, 95.1 and 80.7, respectively.

Example 3

The lithium-containing brine comprises the following components:

organic phase: kerosene is used as a diluent, and the content of compounds N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide and TBP in the kerosene solution is respectively 5%, 5% and 80% (the percentage of each component in the total volume of the organic phase);

adding 1 part of lithium-containing brine into a one-liquid funnel, and adding FeC1₃As co-extraction agent, Fe in water phase³⁺/Li⁺Adding 5 parts of the organic phase as an extraction composition (compared with O/A5/1) at a molar ratio of 1.75, fully mixing the two phases at 40 ℃ for extraction, standing for layering after mixing, achieving good phase separation effect, colorless aqueous phase and clear interface of the two phases, and respectively measuring L i in a balanced aqueous phase and an organic phase⁺、Na⁺、K⁺And Mg²⁺From this, the extraction rate of L i was calculated to be 91.25%, L i⁺、Na⁺、K⁺And Mg² ⁺The partition ratios of (A) to (B) are respectively 2.086, 0.025, 0.026, 0.00322, the separation coefficients of L i/Mg, L i/Na and L i/K are respectively 648, 83.4 and 80.2.

Example 4

The lithium-containing brine comprises the following components:

organic phase: kerosene is used as a diluent, and the content of compounds N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide and trioctyl phosphate in the kerosene solution is respectively 25%, 25% and 10% (the percentage of each component in the total volume of the organic phase);

taking 1 part of lithium-containing brine, adding FeC1₃As co-extraction agent, Fe in water phase³⁺/Li⁺Adding 2 parts of the organic phase (the ratio of O/A to O/A is 2:1) at 25 ℃, fully mixing the two phases for extraction, standing for layering after the mixing is finished, having good phase separation effect, colorless aqueous phase and clear interface of the two phases, and respectively measuring L i in the balanced aqueous phase and the organic phase⁺、Na⁺、K⁺、Mg²⁺From the concentration, the extraction rate of L i was calculated to be 84.28%, L i⁺、Na⁺、K⁺And Mg²⁺The partition ratios of (A) are 2.681, 0.031, 0.045, 0.00489, L i/Mg, L i/Na and L i/K, respectively, and the separation coefficients are 548, 86.5 and 59.6, respectively.

Example 5

The lithium-containing brine comprises the following components:

organic phase: kerosene is used as a diluent, and the content of the compounds N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide and diisoamyl methyl phosphate in the kerosene is respectively 10%, 10% and 20% (the percentage of each component in the total volume of the organic phase).

Taking 1 part of lithium-containing brine, adding FeC1₃As co-extraction agent, Fe in water phase³⁺/Li⁺Adding 2 parts of the organic phase (the ratio of O/A to O/A is 2:1) at 25 ℃, fully mixing the two phases for extraction, standing for layering after the mixing is finished, having good phase separation effect, colorless aqueous phase and clear interface of the two phases, and respectively measuring L i in the balanced aqueous phase and the organic phase⁺、Na⁺、K⁺、Mg²⁺From the concentration, the extraction rate of L i was 81.96%, L i⁺、Na⁺、K⁺And Mg²⁺The partition ratios of (A) are 2.272, 0.036, 0.051, 0.00368, the separation coefficients of L i/Mg, L i/Na and L i/K are 617, 63.1 and 44.5, respectively.

Example 6

The lithium-containing brine comprises the following components:

organic phase: kerosene is taken as a diluent, and the content of compounds N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide, N-dihexylpropionamide and TBP in the kerosene is respectively 10%, 25%, 15% and 10% (the percentage of each component in the total volume of an organic phase);

taking 1 part of lithium-containing brine, adding FeC1₃As co-extraction agent, Fe in water phase³⁺/Li⁺Adding 2 parts of the organic phase (the ratio of O/A to O/A is 2:1) at 25 ℃, fully mixing the two phases for extraction, standing for layering after the mixing is finished, having good phase separation effect, colorless aqueous phase and clear interface of the two phases, and respectively measuring L i in the balanced aqueous phase and the organic phase⁺、Na⁺、K⁺、Mg²⁺From the concentration, the extraction rate of L i was calculated to be 89.79%, L i⁺、Na⁺、K⁺And Mg²⁺The partition ratios of (A) are 4.397, 0.048, 0.053, 0.0069, L i/Mg, L i/Na and L i/K, and the separation coefficients are 637, 91.6 and 83.0, respectively.

Example 7

The lithium-containing brine comprises the following components:

organic phase: kerosene is taken as a diluent, and the contents of compounds N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide, N-dihexylbenzamide and TBP in a kerosene solution are respectively 30%, 10% and 10% (the percentage of each component in the total volume of an organic phase);

taking 2 parts of the organic phase, and adding Fe into the aqueous phase³⁺/Li⁺At a molar ratio of 1.1, FeC1 was added to the organic phase₃.1 part of lithium-containing brine is taken to be mixed with the FeC1₃Mixing the organic phases (the extraction phase ratio is 2:1) and fully mixing the two phases at 25 ℃ for extraction, standing for layering after the mixing is finished, having good phase separation effect, colorless aqueous phase and clear interface of the two phases, and respectively measuring L i in the equilibrium aqueous phase and the organic phase⁺、Na⁺、K⁺、Mg²⁺From the concentration, the extraction rate of L i was calculated to be 83.26%, L i⁺、Na⁺、K⁺And Mg²⁺The partition ratios of (A) are respectively 2.487, 0.039, 0.042, 0.0047, L i/Mg, L i/Na and L i/K, and the separation coefficients are respectively 529, 63.8 and 59.2.

Example 8

The lithium-containing brine comprises the following components:

organic phase: kerosene is taken as a diluent, and the contents of compounds N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide, N-dihexyln-butylamide and TBP in the kerosene solution are respectively 10%, 20%, 10% and 10% (the percentage of each component in the total volume of the organic phase);

taking 1 part of lithium-containing brine, adding FeC1₃As co-extraction agent, Fe in water phase³⁺/Li⁺Adding 2 parts of the organic phase (the ratio of O/A to O/A is 2:1) at 25 ℃, fully mixing the two phases for extraction, standing for layering after the mixing is finished, having good phase separation effect, colorless aqueous phase and clear interface of the two phases, and respectively measuring L i in the balanced aqueous phase and the organic phase⁺、Na⁺、K⁺、Mg²⁺From the concentration, the extraction rate of L i was 88.91%, L i⁺、Na⁺、K⁺And Mg²⁺The partition ratios of (a) were 4.009, 0.051, 0.066, 0.00503, L i/Mg, L i/Na and L i/K, respectively, and the separation coefficients were 797, 78.6, 60.7, respectively.

Example 9

The lithium-containing brine comprises the following components:

organic phase: the contents of N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide and TBP are respectively 30%, 30% and 40% (the contents of all the components account for the total volume of the organic phase);

taking 1 part of lithium-containing brine, adding FeC1₃As co-extraction agent, Fe in water phase³⁺/Li⁺2 parts of the organic phase (the ratio of O/A to O/A is 2:1) is added, the two phases are fully mixed at 40 ℃ for extraction, standing and layering are carried out after the mixing is finished, the phase separation effect is good, the water phase is colorless, the interfaces of the two phases are clear, and L i in the balanced water phase and the organic phase are respectively measured⁺、Na⁺、K⁺、Mg²⁺From the concentration, the extraction rate of L i was calculated to be 90.03%, L i⁺、Na⁺、K⁺And Mg²⁺The partition ratios of (A) are 4.515, 0.055, 0.049, 0.00679, L i/Mg, L i/Na and L i/K, respectively, and the separation coefficients are 665, 82.1 and 92.1, respectively.

Comparative examples 1 to 3

The organic phase was replaced with kerosene solution of N, N-bis (2-ethylhexyl) acetamide + N, N-bis (2-ethylhexyl) -2-hydroxyacetamide + TBP, kerosene solution of N, N-bis (2-ethylhexyl) acetamide + N, N-bis (2-ethylhexyl) tert-butylamide + TBP, kerosene solution of N, N-bis (2-ethylhexyl) acetamide + N, N-bis (2-ethylhexyl) -2-ethoxyacetamide + TBP, respectively, and the remaining operations and conditions were the same as in example 1. The results of the experiments are shown in the following table:

example 10 (Back extraction)

An efficient extraction system is required to have not only excellent extraction performance but also good back-extraction performance.

Organic phase: the lithium ion-containing organic phases obtained in examples 1, 4 and 8;

water phase: hydrochloric acid aqueous solutions of different molar concentrations;

mixing lithium ion-containing organic phase with hydrochloric acid aqueous solution with different molar concentrations (mixing ratio shown in Table 1), oscillating at 24 deg.C for 10 min, standing for layering, and determining L i in equilibrium two phases⁺And (4) concentration. Specific parameters are shown in table 1 below.

Comparative examples 4 and 5 examples of back extraction of N, N-bis (2-ethylhexyl) acetamide + TBP, TBP in patent CN103055539A, were carried out by taking 30 parts of the lithium loaded organic phase after extraction, adding 1 part of 6 mol/L HCl (compared to O/a. about.30), shaking for 10 minutes at 24 ℃ for back extraction, standing for demixing, and determining L i concentrations in the back-extracted equilibrium organic and aqueous phases.

TABLE 1

EXAMPLE 11 preparation of extractant

The general preparation method comprises the steps of respectively adding 1mol of amine reactants, 400m L dichloromethane and 153m L (1.1mol) of triethylamine into a three-necked bottle of 2L equipped with a thermometer, a constant-pressure dropping funnel and a mechanical stirrer, opening the stirrer, cooling the system to 0 ℃, simultaneously placing 1.05mol of acyl chloride and about 200m L dichloromethane solution into the dropping funnel and starting dropwise adding, keeping the temperature of the system not to exceed 15 ℃, completing dropwise adding within about 30 minutes, removing an ice bath, reacting at room temperature overnight, adding equal volume of water to dissolve generated solid, after the separation of the separating funnel, washing an organic phase with dilute hydrochloric acid and saturated common salt water, drying with anhydrous sodium sulfate, removing the solvent, and distilling under reduced pressure.

N, N-di (2-ethylhexyl) acetamide：

The amine reactant is diisooctylamine, the acyl chloride is acetyl chloride, the yield is 90 percent, 138-143 ℃/9 ×10^-2mba；¹HNMR(400MHz,CDCl₃)3.13-3.34(m,2H),3.14(d,2H),2.09(s,1H),1.59-1.68(m,2H),1.23-1.39(m,16H),0.85-0.91(m,12H)；¹³C NMR(100MHz,CDCl₃)170.903,52.095,48.311,38.284,36.898,30.561,30.473,28.752,28.716,23.859,23.764,23.035,22.991,21.970,14.022,13.985,10.806,10.638；IR(thin film):2961,2929,2873,2857,1651,1463,1379,1234,1185,1037cm^-1；MS(ESI):284.7(M⁺+1),306.3(M⁺+Na)；EA:calcd.for C₁₈H₃₇NO:C,76.26；H,13.14；N,4.94,Found:C,76.29；H,13.19；N,4.91.

N, N-dihexylacetamide：

The amine reactant is dihexylamine, the acyl chloride is acetyl chloride, the yield is 97%, 130-142 ℃/6 × 10^-2mba；¹H NMR(400MHz,CDCl₃)3.27(t,2H),3.14(t,2H),2.07(s,3H),1.50-1.53(m,4H),1.27-1.28(m,12H),0.85-0.88(m,6H)；¹³C NMR(100MHz,CDCl₃)170.174,48.866,45.829,31.606,31.490,28.856,27.678,26.679,26.516,22.550,21.404,13.998,13.951；IR(thin film):2957,2929,2873,2858,1648,1458,1422,1378,1260,1108cm^-1；MS(ESI):228.6(M⁺+1),250.3(M⁺+Na)；EA:calcd.for C₁₄H₂₉NO:C,73.95；H,12.86；N,6.16,Found:C,73.00；H,12.87；N,6.15.

N, N-dihexylpropionamide：

The amine reactant is dihexylamine, acyl chloride is propionyl chloride, the yield is 97%, 114-126 ℃/6 × 10^-2mba；¹H NMR(400MHz,CDCl₃)3.13-3.35(m,2H),2.33(dd,2H),1.14-1.16(m,4H),1.20-1.35(m,12H),1.13(t,3H),0.81-0.91(m,6H)；¹³C NMR(100MHz,CDCl₃)173.373,47.913,45.992,31.544,31.464,29.003,27.702,26.609,22.558,13.966,9.682；IR(thin film):2957,2929,2858,1651,1465,1425,1375,1193,1074cm^-1；MS(ESI):242.7(M⁺+1),264.3(M⁺+Na)；EA:calcd.for C₁₅H₃₁NO:C,74.63；H,12.94；N,5.80,Found:C,74.05；H,13.48；N,5.98.

N，N-dihexyl-2-methylpropionamide：

The amine reactant is dihexylamine, the acyl chloride is 2-methylpropanoyl chloride, the yield is 94%, 130-138 ℃/5.8 × 10^- ²mba；¹H NMR(400MHz,CDCl₃)3.19-3.30(m,4H),2.69-2.76(m,1H),1.46-1.55(m,4H),1.21-1.35(m,12H),1.11(s,3H),1.09(s,3H),0.83-0.91(m,6H)；¹³C NMR(100MHz,CDCl₃)176.821,31.544,30.119,26.571,22.558,19.699,13.966；IR(thin film):2959,2929,2858,1644,1470,1425,1378,1135,1085cm^-1；MS(ESI):256.7(M⁺+1),278.3(M⁺+Na)；EA:calcd.for C₁₆H₃₃NO:C,75.23；H,13.02；N,5.48,Found:C,74.88；H,13.40；N,5.87.

N, N-dihexylbenzamide：

The amine reactant is dihexylamine, the acyl chloride is benzoyl chloride, the yield is 95%, 138-148 ℃/7 × 10^-2mba；¹HNMR(400MHz,CDCl₃)7.34-7.37(m,5H),3.35-3.54(m,2H),3.07-3.30(m,2H),1.48-1.63(m,4H),1.00-1.48(m,12H),0.61-0.74(m,6H)；¹³C NMR(100MHz,CDCl₃)171.638,137.296,134.523,130.549,128.992,128.860,128.829,128.310,128.155,126.428,126.304,126.265,48.998,48.874,44.729,44.636,31.598,31.498,31.288,31.157,28.554,28.430,27.585,27.469,27.376,26.780,26.679,26.524,26.253,26.206,22.496,13.959；IR(thin film):2956,2929,2857,1636,1466,1423,1379,1300,1267,1107,1074cm^-1；MS(ESI):290.6(M⁺+1),312.3(M⁺+Na)；EA:calcd.for C₁₉H₃₁NO:C,78.84；H,10.80；N,4.84,Found:C,78.35；H,10.62；N,4.96.

N, N-dihexyl p-methylbenzamide：

The amine reactant is dihexylamine, the acyl chloride is 4-methylbenzoyl chloride, the yield is 96%, and the reaction temperature is 150-170 ℃/7 × 10^- ²mba；¹H NMR(400MHz,CDCl₃)7.16-7.18(m,2H),7.19-7.26(m,2H),3.30-3.48(m,2H),3.19-3.29(m,2H),2.36(s,3H),1.42-1.65(m,4H),1.00-1.39(m,12H),0.75-0.91(m,6H)；¹³C NMR(100MHz,CDCl₃)171.832,138.970,134.322,130.611,129.550,128.891,126.505,49.021,48.959,44.900,44.791,44.737,44.698,31.451,31.226,28.585,28.476,28.438,28.414,28.391,28.329,27.616,27.562,27.500,27.477,27.407,26.811,26.656,26.540,26.540,26.501,26.346,26.299,26.121,22.511,21.318,13.959；IR(thin film):2956,2928,2858,1636,1466,1422,1378,1180,1105,1020cm^-1；MS(ESI):304.7(M⁺+1),326.3(M⁺+Na)；EA:calcd.for C₂₀H₃₃NO:C,79.15；H,10.96；N,4.62,Found:C,78.95；H,11.04；N,4.61.

N, N-dihexyl N-butylamide：

The amine reactant is dihexylamine, the acyl chloride is n-butyl chloride, the yield is 93%, 126-136 ℃/6 × 10^-2mba；¹HNMR(400MHz,CDCl₃)3.12-3.27(m,4H),2.26(t,2H),1.60-1.71(m,2H),1.42-1.55(m,4H),1.20-1.35(m,12H),0.88-1.02(m,9H)；¹³C NMR(100MHz,CDCl₃)172.599,47.991,47.952,45.907,34.953,31.529,29.081,27.717,26.671,26.547,22.558,18.924,13.966；IR(thinfilm):2958,2929,2858,1647,1465,1423,1378,1297,1250,1191,1145,1093cm^-1；MS(ESI):304.7(M⁺+1),326.3(M⁺+Na)；EA:calcd.for C₁₆H₃₃NO:C,75.23；H,13.02；N,5.48,Found:C,74.68；H,13.31；N,5.60.

Claims

1. An extraction composition, comprising: an extractant and a neutral phosphorus-oxygen compound; the extractant comprises: n, N-di (2-ethylhexyl) acetamide and N, N-dihexylacetamide;

the general structure of the neutral phosphorus-oxygen compound is shown as formula A:

2. Such asThe extraction composition of claim 1, wherein: in the neutral phosphorus-oxygen compound, the' straight chain or branched chain C₁-C₁₂Alkyl is "straight-chain or branched C₁-C₈Alkyl groups ";

and/or, in the neutral phosphorus oxygen compound, the' straight chain or branched chain C₁-C₁₂Alkoxy "is" straight-chain or branched C₁-C₈Alkoxy ".

3. The extraction composition of claim 2, wherein: in the neutral phosphorus-oxygen compound, the' straight chain or branched chain C₁-C₁₂Alkyl is "straight-chain or branched C₄-C₈Alkyl groups ";

and/or, in the neutral phosphorus oxygen compound, the' straight chain or branched chain C₁-C₁₂Alkoxy "is" straight-chain or branched C₄-C₈Alkoxy ".

4. The extraction composition of claim 3, wherein: in the neutral phosphorus-oxygen compound, the' straight chain or branched chain C₁-C₁₂Alkyl "is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 1-methyl-heptyl or 2-ethyl-hexyl;

and/or, in the neutral phosphorus oxygen compound, the' straight chain or branched chain C₁-C₁₂Alkoxy "is methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, 1-methyl-heptyloxy or 2-ethyl-hexyloxy.

5. The extraction composition of claim 1, wherein:

the neutral phosphorus-oxygen compound is one or more of the following compounds:

6. the extraction composition of claim 1, wherein: in the extraction composition, the volume ratio of the extraction agent to the neutral phosphorus-oxygen compound is 7: 1-1: 8;

and/or in the extracting agent, the volume ratio of N, N-di (2-ethylhexyl) acetamide to N, N-dihexylacetamide is 10: 1-1: 10;

and/or, the extracting agent can also comprise other amide compounds, and the other amide compounds are one or more of N, N-dihexyl propionamide, N-dihexyl-2-methylpropionamide, N-dihexyl benzamide, N-dihexyl p-methylbenzamide and N, N-dihexyl N-butylamide:

7. the extraction composition of claim 6, wherein: in the extraction composition, the volume ratio of the extracting agent to the neutral phosphorus-oxygen compound is 5:1-1: 5;

and/or the volume ratio of the N, N-di (2-ethylhexyl) acetamide to the N, N-dihexylacetamide in the extractant is 5:1-1: 6.

8. The extraction composition of claim 7, wherein: in the extraction composition, the volume ratio of the extracting agent to the neutral phosphorus-oxygen compound is 5:3-1: 2;

and/or the volume ratio of the N, N-di (2-ethylhexyl) acetamide to the N, N-dihexylacetamide in the extractant is 3:1-1: 2.5.

9. The extraction composition of claim 8, wherein: in the extraction composition, the volume ratio of the extracting agent to the neutral phosphorus-oxygen compound is 2:1-1: 1;

and/or the volume ratio of the N, N-di (2-ethylhexyl) acetamide to the N, N-dihexylacetamide in the extractant is 2:1-1: 2.

10. The extraction composition of claim 9, wherein: in the extraction composition, the volume ratio of the extracting agent to the neutral phosphorus-oxygen compound is 3: 2;

and/or the volume ratio of the N, N-di (2-ethylhexyl) acetamide to the N, N-dihexylacetamide in the extractant is 1:1.

11. The extraction composition of claim 6, wherein: when other amide compounds are contained in the extractant, the content of the N, N-di (2-ethylhexyl) acetamide and the N, N-dihexylacetamide in the extractant is 0.01 to 99.9 percent;

and/or, when other amide compounds are contained in the extracting agent, the volume ratio of the total volume of the N, N-di (2-ethylhexyl) acetamide and the N, N-dihexylacetamide to the other amide compounds is 7:3-6.02: 1;

and/or, the extraction composition further comprises a diluent;

and/or, the extraction composition further comprises a co-extractant;

and/or, when the extraction composition comprises other components besides the extractant and the neutral phosphorus oxygen compound, the total content of the extractant and the neutral phosphorus oxygen compound in the organic phase of the extraction composition is 20-90 percent by volume percent.

12. The extraction composition of claim 11, wherein: when other amide compounds are contained in the extractant, the content of the N, N-di (2-ethylhexyl) acetamide and the N, N-dihexylacetamide in the extractant is 70 to 85.6 percent;

and/or, when other amide compounds are contained in the extracting agent, the volume ratio of the total volume of the N, N-di (2-ethylhexyl) acetamide and the N, N-dihexylacetamide to the other amide compounds is 3:1-4: 1;

and/or, when the extraction composition further comprises a diluent, the diluent is aliphatic hydrocarbon or aromatic hydrocarbon with the boiling point equal to or higher than 100 ℃ under normal pressure, or kerosene;

and/or, when the extraction composition further comprises a co-extractant, the co-extractant is a ferric salt;

and/or, when the extraction composition comprises other components besides the extractant and the neutral phosphorus oxygen compound, the total content of the extractant and the neutral phosphorus oxygen compound in the organic phase of the extraction composition is 40-80 percent, and the percentage is volume percentage.

13. The extraction composition of claim 12, wherein: when other amide compounds are contained in the extractant, the content of the N, N-di (2-ethylhexyl) acetamide and the N, N-dihexylacetamide in the extractant is 75 to 80 percent;

and/or, when the extraction composition further comprises a co-extractant, the co-extractant is ferric trichloride, ferric sulfate, ferric nitrate and/or ferric phosphate;

and/or, when the extraction composition comprises other components besides the extractant and the neutral phosphorus oxygen compound, the total content of the extractant and the neutral phosphorus oxygen compound in the organic phase of the extraction composition is 60 to 70 percent, and the percentage is volume percentage.

14. The extraction composition of claim 13, wherein: when the extraction composition further comprises a co-extractant, the co-extractant is ferric chloride.

15. The extraction composition of claim 11, wherein:

when the extraction composition further comprises a diluent, the amount of the diluent is 10 to 80 percent, and the percentage is the volume percentage of the diluent relative to the total volume of the extraction composition;

when the extraction composition further comprises a co-extraction agent, the dosage of the co-extraction agent ensures that the molar ratio of ferric ions to lithium ions in the substance to be extracted is 1:1.75-2: 1; the material to be extracted is lithium-containing brine.

16. The extraction composition of claim 15, wherein:

when the extraction composition further comprises a diluent, the amount of the diluent is 20 to 60 percent, and the percentage is the volume percentage of the diluent relative to the total volume of the extraction composition;

when the extraction composition further comprises a co-extraction agent, the dosage of the co-extraction agent ensures that the molar ratio of ferric ions to lithium ions in the substance to be extracted is 1.3:1-1.75: 1.

17. The extraction composition of claim 16, wherein:

when the extraction composition further comprises a diluent, the amount of the diluent is 30 to 40 percent, and the percentage is the volume percentage of the diluent relative to the total volume of the extraction composition;

when the extraction composition further comprises a co-extraction agent, the dosage of the co-extraction agent ensures that the molar ratio of ferric ions to lithium ions in the substance to be extracted is 1:1-1.5: 1.

18. The extraction composition of claim 17, wherein: when the extraction composition further comprises a co-extraction agent, the dosage of the co-extraction agent is such that the molar ratio of ferric ions to lithium ions in the substance to be extracted is 1.1: 1.

19. The extraction composition of claim 1, wherein:

the extractant consists of N, N-di (2-ethylhexyl) acetamide and N, N-dihexylacetamide.

20. The extraction composition of claim 1, wherein: the extractant consists of N, N-di (2-ethylhexyl) acetamide, N-dihexylacetamide and one or more of N, N-dihexylpropionamide, N-dihexyl-2-methylpropionamide, N-dihexylbenzamide, N-dihexyl p-methylbenzamide and N, N-dihexyl N-butylamide;

and/or the extraction composition consists of the extractant, the neutral phosphorus-oxygen compound shown as the formula A and a diluent.

21. The extraction composition of claim 1, wherein: the extraction composition consists of the extraction agent, the neutral phosphorus-oxygen compound shown as the formula A, a diluent and a co-extraction agent.

22. An extraction system comprising the extraction composition of any one of claims 1 to 21 and a lithium-containing brine.

23. The extraction system of claim 22, wherein: in the extraction system, the lithium-containing brine is lithium-containing brine with high magnesium-lithium ratio, and the high magnesium-lithium ratio is Mg in the lithium-containing brine²⁺/Li⁺The molar ratio of (A) to (B) is 2-30;

in the extraction system, the volume ratio of the organic phase of the extraction composition to the lithium-containing brine is 1:5-10: 1;

and/or in the extraction system, the extraction composition contains a co-extraction agent, and the concentration of the co-extraction agent in lithium-containing brine is 0.05 mol/L-3.5 mol/L.

24. The extraction system of claim 23, wherein: in the extraction system, the lithium-containing brine is lithium-containing brine with high magnesium-lithium ratio, and the high magnesium-lithium ratio is Mg in the lithium-containing brine²⁺/Li⁺Is 16;

and/or the lithium-containing brine comprises L i of 0.02 mol/L-2.0 mol/L⁺2.0 mol/L-5.0 mol/L of Mg²⁺0 mol/L-0.5 mol/L of Na⁺K of 0 mol/L-0.5 mol/L⁺And Cl of not less than 6 mol/L^-0 mol/L-0.90 mol/L of B₂O₃And 0.001 mol/L-0.5 mol/L of H⁺；

And/or in the extraction system, the volume ratio of the organic phase of the extraction composition to the lithium-containing brine is 1:2-6: 1.

25. The extraction system of claim 24, wherein the lithium-containing brine comprises L i in an amount of 0.144 mol/L to 2.0 mol/L⁺4 mol/L-4.64 mol/L of Mg²⁺0.05 mol/L-0.4 mol/L of Na⁺K of 0.02 mol/L-0.4 mol/L⁺9.2 to 10.7 mol/L of Cl^-0 mol/L-0.1 mol/L of B₂O₃And 0.04 mol/L-0.3 mol/L of H⁺；

And/or in the extraction system, the volume ratio of the organic phase of the extraction composition to the lithium-containing brine is 5:1-1: 1.

26. The extraction system of claim 25, wherein:

the lithium-containing brine comprises L i of 0.29 mol/L-2.0 mol/L⁺4 mol/L-4.32 mol/L of Mg²⁺0.05 mol/L-0.1 mol/L of Na⁺K of 0.02 mol/L-0.4 mol/L⁺9.8-10.7 mol/L Cl^-0 mol/L-0.01 mol/L of B₂O₃And 0.04 mol/L-0.05 mol/L of H⁺；

And/or, in the extraction system, the volume ratio of the organic phase of the extraction composition to the lithium-containing brine is 2: 1.

27. An extraction process comprising the steps of: extracting a lithium-containing brine using the extraction composition of any one of claims 1 to 21.

28. The extraction process of claim 27, wherein: the extraction composition comprises a diluent and a co-extractant, and the extraction method comprises the following steps: mixing the organic phase of the extraction composition containing the diluent, the extracting agent and the neutral phosphorus-oxygen compound with lithium-containing brine containing the co-extracting agent, oscillating or stirring for balancing, and standing for layering.

29. The extraction process of claim 27, wherein:

in the extraction method, the temperature of the extraction composition organic phase and the lithium-containing brine is 10-50 ℃.

30. The extraction process of claim 29, wherein: in the extraction method, the temperature of the extraction composition organic phase and the lithium-containing brine is 20-40 ℃.

31. The extraction process of claim 30, wherein: in the extraction method, the temperature of the extraction composition organic phase and the lithium-containing brine is 25-30 ℃.

32. A stripping process comprising the steps of: mixing the lithium-containing organic phase obtained by the extraction method of any one of claims 27 to 31 with an aqueous acid solution, oscillating or stirring for balancing, and standing for layering.

33. The stripping process of claim 32, wherein:

in the back extraction method, the molar concentration of the aqueous acid solution is 0.5 mol/L-12 mol/L, and the molar concentration refers to the ratio of the amount of the substance of the acid to the total volume of the aqueous acid solution;

and/or, in the back extraction method, the acid in the acid aqueous solution is inorganic acid;

and/or in the back extraction method, the volume ratio of the lithium-containing organic phase to the acid aqueous solution is 1:1-50: 1;

and/or, the back extraction process is carried out at 10-50 ℃.

34. The stripping process of claim 33, wherein:

in the back extraction method, the molar concentration of the aqueous acid solution is 4-10 mol/L, and the molar concentration refers to the ratio of the amount of the substance of the acid to the total volume of the aqueous acid solution;

and/or, in the back extraction method, the inorganic acid is one or more of hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid;

and/or in the back extraction method, the volume ratio of the lithium-containing organic phase to the acid aqueous solution is 5:1-40: 1;

and/or, the stripping process is carried out at 24-25 ℃.

35. The stripping process of claim 34, wherein:

in the back extraction method, the molar concentration of the aqueous acid solution is 6-8 mol/L, and the molar concentration refers to the ratio of the amount of the substance of the acid to the total volume of the aqueous acid solution;

and/or, in the back extraction method, the inorganic acid is hydrochloric acid;

and/or in the back extraction method, the volume ratio of the lithium-containing organic phase to the acid aqueous solution is 10:1-30: 1.