CN107619929B

CN107619929B - Application of amide compounds, extraction composition containing amide compounds and extraction system

Info

Publication number: CN107619929B
Application number: CN201610560041.5A
Authority: CN
Inventors: 袁承业; 李晋峰
Original assignee: Shanghai Institute of Organic Chemistry of CAS
Current assignee: Shanghai Institute of Organic Chemistry of CAS
Priority date: 2016-07-15
Filing date: 2016-07-15
Publication date: 2020-08-07
Anticipated expiration: 2036-07-15
Also published as: CN107619929A

Abstract

The invention discloses an amideThe amide compound or the extraction composition containing the amide compound can extract and strip lithium from lithium-containing brine, the extraction rate of L i of the lithium-containing brine is more than 83.89%, the lithium-magnesium distribution coefficient is more than 521, and when HCl is used for stripping lithium, the stripping rate is more than 91.74%, the corrosion to equipment is low, and the extraction composition is suitable for industrial operation requirements.

Description

Application of amide compounds, extraction composition containing amide compounds and extraction system

Technical Field

The invention relates to application of an amide compound, an extraction composition containing the amide compound and an extraction system.

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 is an important material for fuel and nuclear fission reaction of a future nuclear fusion reactor, the demand of which as a battery material is increasing, therefore, lithium is called as energy metal of 21 st century, the demand of lithium is continuously increasing at home and abroad, and the research, development and utilization of lithium resources are urgently needed.

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, specifically as follows:

(1) 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 FeC1 into brine₃As co-extraction agent, using 80% diisobutyl ketone-20% tributyl phosphate as organic phase, using L i and Fe as L iFeC1₄Form co-extraction is carried out into an organic phase and a large amount of MgC1 is mixed with an aqueous phase₂And other metals, the system has higher selectivity for L i extraction, but water back extraction produces L iCl and FeC1₃The 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 the operation is complicated, and the application of the mixed solution in industrial production is not seen so far.

(2) In 1979, the research institute of Qinghai salt lake of Chinese academy of sciences proposed a system and a process for extracting lithium from kerosene solution of tributyl phosphate as a single extractant, thereby simplifying the extraction system, and in 1984, a semi-industrial test for extracting lithium from chadan salt lake brine was carried out, and in 1987, a Chinese patent of invention [3. Huangshi Qiang et al, Chinese patent of invention, CN87103431] was applied and granted. However, the extraction agent adopted in the system is tributyl phosphate (TBP), which has strong corrosiveness to extraction equipment, and the tributyl phosphate is not only dissolved and lost in water in long-term operation, but also is easy to degrade 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.

(3) Since 2010, the Qinghai salt lake research institute of Chinese academy of sciences and the Shanghai organic chemistry research institute of Chinese academy of sciences have cooperated to develop a technology and a method for extracting lithium salt from lithium-containing brine, which can reduce the corrosivity to equipment and is suitable for industrial application, wherein the technology and the method adopt a mixture of an amide compound or an amide compound and a neutral phosphorus-oxygen compound as an extractant, ferric trichloride as a co-extractant and aliphatic hydrocarbon or aromatic hydrocarbon as a diluent to extract lithium. Chinese patent application [ yuanyuan et al, chinese patent application, CN103055539A ] was filed in 2011 and granted. The performance of the extractant for extracting lithium is systematically researched, the process test research of an amide and neutral phosphorus-oxygen mixed system is completed, and the optimal process condition of the process flow is determined. The process experiment research of the N523-TBP-sulfonated kerosene extraction system is completed, and the optimal process conditions of the process are determined, but the method has many problems in the industrialization process, such as high water solubility and strong corrosion to equipment due to the existence of TBP. In order to solve the problem of TBP water solubility, a large number of TBP recovery devices and water phase deoiling devices are added at raffinate, strip liquor and each water phase outlet, so that the process flow is greatly lengthened, and the production cost is increased. In order to solve the problem of TBP corrosivity, the material of core equipment has very strict requirements, and equipment made of a large amount of Hastelloy and fluoroplastic materials is selected, so that the equipment investment is very large. In addition, due to the mixed extraction system, the TBP water solubility is larger than that of N523, the TBP amount of an extracting agent in an organic phase is obviously reduced after the organic phase is operated for a period of time, so that the process is unstable, and the TBP needs to be supplemented frequently. The presence of TBP also affects the purification of subsequent products, often with higher phosphorus content.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of long process, complex operation, strong corrosion to equipment, large solvent loss of an extracting agent and the like in the conventional extraction system and process for extracting lithium salt from lithium-containing brine, and provide an application of an amide compound, an extraction composition containing the amide compound and an extraction system. The amide compound can extract and back extract lithium from lithium-containing brine, has high lithium extraction rate and back extraction rate, large separation factor of lithium and sodium, potassium and magnesium, small corrosion to equipment and is suitable for industrial operation requirements.

The invention mainly solves the technical problems through the following technical scheme.

The invention provides an extraction composition, which is characterized by comprising an extracting agent N, N-dihexyl N-butylamide and a diluent, but not comprising neutral phosphorus oxide shown as a formula A,

wherein, in the neutral phosphorus oxygen compound shown as the formula A, R¹And R²Independently is C₁-C₁₂Straight-chain or branched alkyl, C₁-C₁₂Straight chain orA branched alkoxy, phenyl, substituted phenyl, phenoxy, substituted phenoxy, thienyl, pyridyl, or naphthyl group; said substituent of said substituted phenyl or said substituted phenoxy is one or more of the following groups: halogen, C₁-C₆Alkyl, hydroxy, C₁-C₆Alkoxy, trifluoromethyl, trifluoromethoxy, phenoxy, piperidinyl, morpholinyl, pyrrolyl, tetrahydropyrrolyl, nitro and amino; when the substituent is plural, the substituents may be the same or different.

In the neutral phosphorus-oxygen compound shown as the formula A, R¹And R²Preferably C₁-C₈Straight-chain or branched alkyl, or C₁-C₈Linear or branched alkoxy; wherein, said C₁-C₈The linear or branched alkyl group is preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 1-methyl-heptyl or 2-ethyl-hexyl. Said C₁-C₈The linear or branched alkoxy group is preferably methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, 1-methyl-heptoxy or 2-ethyl-hexyloxy.

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

the diluent can be any diluent conventional in the art, preferably an aliphatic hydrocarbon (for example n-dodecane) or an aromatic hydrocarbon with a boiling point greater than or equal to 100 ℃ at atmospheric pressure, and can also be kerosene. The amount of the diluent to be used is not particularly limited as long as the extraction performance of the extractant is not affected. The volume content of the diluent is preferably 5% -95%, and more preferably 20% -95%, and the percentage refers to the volume percentage of the diluent in the total volume of the extraction composition.

The extraction composition may further comprise a co-extractant. The co-extractant can be dissolved in the water phase firstly during extraction, and can also be stabilized in the organic phase firstly. The co-extractant generally refers to ferric salt capable of obviously improving the extraction rate of lithium, and can be one or more of ferric trichloride, ferric sulfate, ferric nitrate and ferric phosphate, and preferably is ferric trichloride. The dosage of the co-extraction agent can be the conventional dosage in the fields of lithium-containing brine extraction and lithium back extraction, and is generally calculated according to the content of lithium in a substance to be extracted, and the substance to be extracted is preferably lithium-containing brine; the amount of the co-extractant used is generally such that the molar ratio of ferric ions to lithium ions is from 1:1 to 2:1, more preferably from 1.1:1 to 1.7:1, and still more preferably from 1.1:1 to 1.3: 1.

The present invention provides the use of an extraction composition as hereinbefore described for extracting or stripping lithium from lithium-containing brines.

The application of extracting lithium from lithium-containing brine preferably comprises the following steps: mixing the extraction composition with lithium-containing brine, oscillating or stirring for balancing, and standing for layering.

The use of stripping lithium from lithium-containing brine preferably comprises the steps of:

(1) mixing the extraction composition with lithium-containing brine, oscillating or stirring for balancing, standing for layering to obtain an organic phase loaded with lithium ions;

(2) and mixing the lithium ion loaded organic phase with an acid aqueous solution, oscillating or stirring for balancing, and standing for layering.

In the application of extracting lithium from lithium-containing brine or the application of back-extracting lithium from lithium-containing brine, mass transfer is carried out by oscillation. In addition, the mass transfer and phase separation process can be completed 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.

In the application of extracting lithium from lithium-containing brine or the application step (1) of extracting lithium from lithium-containing brine, the volume ratio of the extracted organic phase to the lithium-containing brine can be the conventional volume ratio in the field, preferably 1:5-10:1, more preferably 2:1-6: 1; in the present invention, the organic phase of the extraction composition generally refers to the extraction composition when no co-extractant is included.

In the application of extracting lithium from lithium-containing brine or the application of back-extracting lithium from lithium-containing brine, the temperature of the extraction composition and the lithium-containing brine is preferably 10 ℃ to 50 ℃, and more preferably 20 ℃ to 40 ℃ (for example 24 ℃ to 25 ℃), namely, the operation of oscillating or stirring balance is carried out at 10 ℃ to 50 ℃ (preferably 20 ℃ to 40 ℃). The period of said shaking or stirring equilibration may be a period conventional in the art, preferably from 5 to 30 minutes. (e.g., 10 minutes)

In the application of the back extraction of lithium from lithium-containing brine, in the step (2), the molar concentration of the aqueous solution of the acid is preferably 0.5 mol/L-12.0 mol/L, more preferably 4 mol/L-10 mol/L, more preferably 6 mol/L-8 mol/L, the molar concentration refers to the ratio of the amount of the substance of the acid to the total volume of the aqueous solution of the acid, the acid in the aqueous solution of the acid can be conventional acid in the art, preferably inorganic acid, the inorganic acid is preferably one or more of hydrochloric acid, sulfuric acid and nitric acid, more preferably hydrochloric acid, and the volume ratio of the organic phase carrying lithium ions to the aqueous solution of the acid can be conventional volume ratio in the art, preferably 1:1-50:1, more preferably 5:1-40:1, more preferably 10:1-30: 1.

In the present invention, the lithium-containing brine may be lithium-containing brine containing lithium ions which is conventional in the art, and the present invention preferably selects lithium-containing brine containing high magnesium-lithium ratio, the molar ratio of Mg/L i in the lithium-containing brine containing high magnesium-lithium ratio is preferably 1.5 to 240 (for example, 16), and the lithium-containing brine preferably contains L i of 0.02 mol/L to 2.0 mol/L⁺2.0 mol/L-5.0 mol/L of Mg²⁺(e.g., 3 mol/L-4.8 mol/L), 0 mol/L-0.5 mol/L of Na⁺(e.g., 0.1 mol/L-0.4 mol/L), 0 mol/L-0.5 mol/L K⁺(e.g., 0.02 mol/L-0.4 mol/L) and ≧ 6 mol/L of Cl^-(e.g., 9.0 mol/L-10.2 mol/L), 0 mol/L-0.90 mol/L of B₂O₃(e.g., 0-0.1 mol/L) and 0.001 mol/L-0.5 mol/L of H⁺(e.g., 0.005 mol/L-0.5 mol/L) (acidity of brine), and the balance water.

The above-mentionedIn lithium-containing brine of (1)⁺The concentration of (B) is preferably 0.005 mol/L-0.5 mol/L.

The invention provides application of an amide compound in extraction or back extraction of lithium from lithium-containing brine, wherein the amide compound is N, N-dihexyl N-butylamide.

The application of extracting lithium from lithium-containing brine preferably comprises the following steps: mixing N, N-dihexyl N-butylamide with lithium-containing brine, oscillating for balancing, and standing for layering.

(1) mixing N, N-dihexyl N-butylamide and lithium-containing brine, oscillating or stirring for balancing, and standing for layering to obtain an organic phase loaded with lithium ions;

In the application of extracting lithium from lithium-containing brine or the application step (1) of extracting lithium from lithium-containing brine, the volume ratio of N, N-dihexyl N-butylamide to the lithium-containing brine can be the volume ratio conventional in the art, and is preferably 1:5-10:1, and more preferably 2:1-6: 1.

In the application of extracting lithium from lithium-containing brine or the application of back-extracting lithium from lithium-containing brine, the temperature of the N, N-dihexyl N-butylamide and the lithium-containing brine is preferably 10-50 ℃ during the oscillating or stirring balancing, and is further preferably 20-40 ℃ (such as 24-25 ℃), namely the oscillating or stirring balancing operation is carried out at 10-50 ℃ (preferably 20-40 ℃). The period of said shaking or stirring equilibration may be a period conventional in the art, preferably from 5 to 30 minutes. (e.g., 10 minutes)

In the present invention, the lithium-containing brine may be lithium-containing brine containing lithium ions which is conventional in the art, and the present invention preferably selects lithium-containing brine containing high magnesium-lithium ratio, the molar ratio of Mg/L i in the lithium-containing brine containing high magnesium-lithium ratio is preferably 1.5 to 240 (for example, 16), and the lithium-containing brine preferably contains L i of 0.02 mol/L to 2.0 mol/L⁺2.0 mol/L-5.0 mol/L of Mg²⁺(e.g., 3 mol/L-4.8 mol/L), 0 mol/L-0.5 mol/L of Na⁺(e.g., 0.05 mol/L-0.4 mol/L), 0 mol/L-0.5 mol/L K⁺(e.g., 0.02 mol/L-0.4 mol/L) and ≧ 6 mol/L of Cl^-(e.g., 9.0 mol/L-10.2 mol/L), 0 mol/L-0.90 mol/L of B₂O₃(e.g., 0-0.1 mol/L) and 0.001 mol/L-0.5 mol/L of H⁺(e.g., 0.005 mol/L-0.5 mol/L) (acidity of brine), and the balance water.

H in the lithium-containing brine⁺The concentration of (B) is preferably 0.005 mol/L-0.5 mol/L.

The invention also provides an extraction system comprising lithium-containing brine and N, N-dihexyl N-butylamide; or a lithium-containing brine and the extraction composition.

Wherein, the volume ratio of the N, N-dihexyl N-butylamide to the lithium-containing brine can be the conventional volume ratio in the field, preferably 1:5-10:1, more preferably 2:1-6: 1; the volume ratio of the extraction composition to the lithium-containing brine can be conventional in the art, preferably 1:5 to 10:1, more preferably 2:1 to 6: 1.

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.

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

In the present invention, the volume ratio or volume fraction refers to the volume ratio or volume fraction of each substance at room temperature.

In the present invention, room temperature means 10 ℃ to 30 ℃.

The extraction agent and the extraction system adopted by the invention have the positive effects that the extraction rate of L i of the brine lithium is more than 83.89 percent and can reach 94.35 percent at most, the lithium-magnesium separation factor is more than 521 and can reach 728, when the concentrated HCl is used for back extraction of lithium, the back extraction rate is more than 91.74 percent, the extraction and back extraction performances of extracting lithium salt from the brine lithium are greatly improved, the use of TBP is avoided, the water solubility and the corrosivity of the extraction agent are greatly reduced, the cost is saved, and the method is more suitable for industrial production.

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.

In the following examples, the basic concepts of phase comparison, partition ratio, extraction ratio and extraction separation factor.

(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.

Examples 1 to 3

Organic phase: n, N-dihexyl N-butylamide plus diluent

Water phase: a lithium-containing brine;

comparison (O: A): refers to the volume ratio of the organic phase to the aqueous phase;

the specific operation is as follows:

adding a certain amount of FeCl₃Adding the co-extraction agent into lithium-containing brine, shaking to dissolve, adding organic phase, oscillating for 5-30 min, standing for layering to obtain equilibrium water phase and organic phase containing loaded lithium ions, and measuring L i in the equilibrium water phase and organic phase respectively⁺、Na⁺、K⁺And Mg²⁺The extraction rate of L i, L i, was calculated from the concentration of (b)⁺、Mg²⁺、Na⁺And K⁺Partition ratio of L i/Mg, L i/Na, and L i/K.

Example 4

Organic phase: n, N-dihexyl N-butylamide

Water phase: a lithium-containing brine;

the specific operation is as follows:

adding a certain amount of FeCl₃(Co-extractant) additionShaking to dissolve in lithium-containing brine, adding organic phase, oscillating for 30 min, standing for layering to obtain balanced water phase and organic phase containing loaded lithium ions, and measuring L i in the balanced water phase and the organic phase respectively⁺、Na⁺、K⁺And Mg²⁺The extraction rate of L i, L i, was calculated from the concentration of (b)⁺、Mg²⁺、Na⁺And K⁺Partition ratio of L i/Mg, L i/Na, and L i/K.

The contents of each ion in the lithium-containing brine in examples 1 to 4 are shown in table 1:

TABLE 1 content of each ion in the lithium-containing brine in examples 1 to 4 (mol/L)

Numbering	Li⁺	Mg²⁺	Na⁺	K⁺	Cl^-	B₂O₃	H⁺	Ratio of magnesium to lithium
									1	0.29	4.64	0.1	0.02	9.8	0.01	0.037	16
2	0.02	4.8	0.1	0.4	10.2	0.1	0.005	240
									3	2	3	0.4	0.02	9.0	0	0.5	1.5
4	0.29	4.64	0.1	0.02	9.8	0.01	0.037	16

Examples 1-4 extraction conditions and parameters are shown in table 2:

1. 50% N, N-dihexyl N-butylamide-50% kerosene

2. 5% N, N-dihexyl N-butylamide 95% N-dodecane

3. 80% N, N-dihexyl N-butylamide-20% kerosene

4. 100% N, N-dihexyl N-butylamide

TABLE 2 extraction conditions and parameters of examples 1-4

Numbering	Extraction phase ratio O/A	Fe/L i molar ratio	Extraction temperature (. degree.C.)
				1	2	1.3	25
2	5	1.1	10
				3	10	1.75	40
4	2	1.3	25

The results of the extraction of examples 1 to 4 are shown in table 3:

TABLE 3 extraction results of examples 1 to 4

Comparative example 1

The organic phase was replaced with N, N-dihexylacetamide plus kerosene, respectively, and the other operations and conditions were the same as in example 1. The results of the experiment are shown in table 4.

TABLE 4 extraction results of comparative example 1

Example 5

Adding a certain amount of FeCl₃(Co-extraction agent) 60 parts by volume of lithium-containing brine (FeCl) was added₃The dosage and the content of each component in the lithium-containing brine are shown in examples 1 and 4), after shaking for dissolving, 30 parts by volume of the organic phase in examples 1 and 4 are added, shaking is carried out for 10 minutes, extraction is carried out, and the organic phase loaded with lithium ions is obtained, 30 parts by volume of the organic phase loaded with lithium ions is mixed with 1 part by volume of 6 mol/L hydrochloric acid aqueous solution, shaking is carried out for 10 minutes at 24 ℃, back extraction is carried out, standing and layering are carried out, and L i in two phases of back extraction equilibrium is measured⁺The concentrations, specific parameters are shown in table 5 below, and the specific conditions and parameters for the back-extraction of comparative examples 2 and 3 are described in patent CN 103055539A.

TABLE 5 back extraction results data sheet

The preparation of the extractant referred to in the examples is as follows:

experiment general procedure in a three-necked flask equipped with thermometer, constant pressure dropping funnel, mechanically stirred 2L, dialkylamine 1mol, 400m L dichloromethane and 153m L (1.1mol) triethylamine were added, stirring was turned on, the system was cooled to 0 ℃ and 1.05mol of acid chloride and about 200m L dichloromethane solution were put into the dropping funnel and started to drop at a temperature not exceeding 15 ℃ for about 30 minutes, the ice bath was removed, the reaction was carried out overnight at room temperature, an equal volume of water was added to dissolve the resulting solid, the organic phase was washed with dilute hydrochloric acid and saturated brine after the separation in the separating funnel, dried over anhydrous sodium sulfate, the solvent was removed, and distilled under reduced pressure.

Wherein Yield is Yield, IR (thin film) is infrared (thin film method), EA is elementary analysis, calcd.

N, N-dihexylacetamide

(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-dihexyl N-butylamide

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(thin film):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 which is N, N-dihexyl N-butylamide and a diluent, but which does not comprise neutral phosphorus oxide as shown in formula a;

wherein, in the neutral phosphorus oxygen compound shown as the formula A, R¹And R²Independently is C₁-C₁₂Straight-chain or branched alkyl, C₁-C₁₂Linear or branched alkoxy, phenyl, substituted phenyl, phenoxy, substituted phenoxy, thienyl, pyridyl or naphthyl; said substituent of said substituted phenyl or said substituted phenoxy is one or more of the following groups: halogen, C₁-C₆Alkyl, hydroxy, C₁-C₆Alkoxy, trifluoromethyl, trifluoromethoxy, phenoxy, piperidinyl, morpholinyl, pyrrolyl, tetrahydropyrrolyl, nitro and amino; when the substituent is plural, the substituents may be the same or different.

2. The extraction composition of claim 1, wherein the diluent is one or more of an aliphatic hydrocarbon having a boiling point at atmospheric pressure of greater than or equal to 100 ℃, an aromatic hydrocarbon having a boiling point at atmospheric pressure of greater than or equal to 100 ℃, and kerosene.

3. The extraction composition of claim 2, wherein the diluent is kerosene and/or n-dodecane.

4. The extraction composition of claim 1, wherein the diluent comprises about 5% to about 95% by volume of the total extraction composition.

5. The extraction composition of claim 4, wherein the diluent is present in an amount of from 20% to 95% by volume, the volume being the percentage of the volume of diluent to the total volume of the extraction composition.

6. The extraction composition of any one of claims 1 to 4, further comprising a co-extractant.

7. The extraction composition of claim 6, wherein the co-extractant is one or more of ferric chloride, ferric sulfate, ferric nitrate, and ferric phosphate; the dosage of the co-extraction agent is calculated by the content of lithium in the material to be extracted, and the material to be extracted is lithium-containing brine; the dosage of the co-extraction agent ensures that the molar ratio of ferric ions to lithium ions is 1:1-2: 1.

8. The extraction composition of claim 7, wherein said co-extractant is ferric chloride.

9. The extraction composition of claim 7, wherein the co-extractant is used in an amount such that the molar ratio of ferric ion to lithium ion is from 1:1 to 1.75: 1.

10. Use of an extraction composition according to any one of claims 1 to 9 for extracting or stripping lithium from a lithium-containing brine.

11. The use of claim 10, wherein the use of extracting lithium from a lithium-containing brine comprises the steps of: mixing the extraction composition of any of claims 1-9 with a lithium-containing brine, equilibrating with shaking or stirring, and allowing to stand for layering.

12. The use of claim 10, wherein the use of stripping lithium from a lithium-containing brine comprises the steps of:

(1) mixing the extraction composition of any of claims 1-9 with a lithium-containing brine, shaking or stirring to equilibrate, standing to stratify to obtain a lithium ion-loaded organic phase;

13. The use of claim 11 or 12, wherein in said step (1) of extracting lithium from a lithium-containing brine, or said step of back-extracting lithium from a lithium-containing brine, the volume ratio of the organic phase of the extraction composition to said lithium-containing brine is from 1:5 to 10: 1; the organic phase of the extraction composition refers to the extraction composition without the co-extractant.

14. The use of claim 13, wherein the volume ratio of the extraction composition organic phase to the lithium-containing brine is from 2:1 to 6: 1.

15. The use according to claim 12, wherein in step (2) of the use for stripping lithium from lithium-containing brine, the molar concentration of the aqueous acid solution is 0.5 mol/L-12.0 mol/L, the molar concentration being the ratio of the amount of acid material to the total volume of the aqueous acid solution;

and/or, in the application of back extracting lithium from lithium-containing brine, in the step (2), the acid in the acid aqueous solution is inorganic acid;

and/or in the application of back extracting lithium from the lithium-containing brine, in the step (2), the volume ratio of the lithium ion-loaded organic phase to the acid aqueous solution is 1:1-50: 1.

16. The use according to claim 15, wherein in the step (2) of stripping lithium from lithium-containing brine, the molar concentration of the aqueous acid solution is from 4 mol/L to 10 mol/L, the molar concentration being the ratio of the amount of acid species to the total volume of the aqueous acid solution.

17. The use according to claim 15, wherein in the step (2) of stripping lithium from lithium-containing brine, the molar concentration of the aqueous acid solution is from 6 mol/L to 8 mol/L, the molar concentration being the ratio of the amount of acid species to the total volume of the aqueous acid solution.

18. The use of claim 15, wherein in the step (2) of stripping lithium from lithium-containing brine, the acid in the aqueous acid solution is a mineral acid, and the mineral acid is one or more of hydrochloric acid, sulfuric acid and nitric acid.

19. The use according to claim 15, wherein in the use for stripping lithium from lithium-containing brine, in step (2), the volume ratio of the lithium ion-laden organic phase to the aqueous acid solution is from 5:1 to 40: 1.

20. The use according to claim 15, wherein in the use for stripping lithium from lithium-containing brine, in step (2), the volume ratio of the lithium ion-laden organic phase to the aqueous acid solution is from 10:1 to 30: 1.

21. The use of claim 11 or 12, wherein in said use for extracting or stripping lithium from a lithium-containing brine, the temperature of said extraction composition and said lithium-containing brine at said equilibrium with shaking or stirring is in the range of 10 ℃ to 50 ℃;

and/or, in the application of extracting lithium or stripping lithium from lithium-containing brine, the oscillating or stirring balancing time is 5-30 minutes;

and/or in the application of extracting or back-extracting lithium from the lithium-containing brine, the molar ratio of Mg/L i is 1.5-240, and 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⁺、0mol/L-0.5mK of ol/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 the balance of water.

22. The use of claim 21, wherein the lithium-containing brine comprises L i at 0.02 mol/L-2.0 mol/L⁺3 mol/L-4.8 mol/L of Mg²⁺0.1 mol/L-0.4 mol/L of Na⁺K of 0.02 mol/L-0.4 mol/L⁺9.0 mol/L-10.2 mol/L Cl^-0-0.1 mol/L of B₂O₃And 0.005 mol/L-0.5 mol/L of H⁺And the balance of water.

23. An extraction system comprising lithium-containing brine and an extraction composition as claimed in any one of claims 1 to 9.