Extraction agent and extraction method for lithium precipitation mother liquor

Abstract

The present application discloses a lithium extraction agent and extraction method for lithium mother liquor. The lithium extraction agent includes a solute and an organic solvent, the solute includes at least one of 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraketone and terpyridine, and the organic solvent includes at least one of dichloromethane, chloroform, carbon tetrachloride, bromobenzene, and carbon disulfide. The lithium extraction agent of the present application can be used to extract lithium in a lithium mother liquor with a wide pH range. After entering the lithium extraction agent, the lithium ions are quickly complexed with the solute in the lithium extraction agent to form a solid phase. It is only necessary to stand the extracted mixed solution A for phase separation. Lithium is present in the lithium-containing solid complex of the lower oil phase. The lower oil phase can be filtered to obtain the lithium-containing solid complex, and the residual amount of sodium in the lithium-containing solid complex is small. In addition, the extraction method of the present application can omit the washing and stripping sections of the rear end of the traditional extraction process, greatly shortening the extraction process and saving production costs.

Description

Technical Field

[0001] The present application relates to the technical field of extraction and separation, and in particular to an extraction agent and an extraction method for extracting lithium from lithium precipitated mother liquor. Background Art

[0002] Lithium occupies a pivotal position in the fields of new energy and modern industry. At present, secondary resources such as lithium ore or waste lithium batteries are mostly recovered by wet process. Lithium mother liquor is an alkaline solution with high sodium and low lithium produced after carbon precipitation. It still contains about 2 g / L of lithium. It is a typical low-concentration lithium-containing solution and still has certain economic value. At present, the residual lithium in lithium mother liquor is mainly recovered by crystallization, electrodialysis and resin adsorption, but there are disadvantages of long separation process and high cost.

[0003] The extraction method has the advantages of high separation efficiency and strong continuity. It has been widely reported in the fields of lithium extraction from salt lakes and lithium recovery from lithium precipitation mother liquor. Most of them use traditional extraction agents such as tributyl phosphate and β-diketone, which have the disadvantages of strong water solubility and high price. In addition, it has to go through multiple processes such as extraction, washing, and stripping, resulting in large equipment investment and high operating costs. Summary of the invention

[0004] The embodiments of the present application provide an extracting agent and an extraction method for extracting lithium from a lithium precipitation mother liquor, which can solve the problem of complex extraction process for separating lithium from a lithium precipitation mother liquor by an extraction method.

[0005] In a first aspect, the present application provides an extractant for extracting lithium from a lithium precipitation mother liquor, which is used to extract lithium from a lithium precipitation mother liquor. The lithium extraction extractant includes a solute and an organic solvent, wherein the solute includes at least one of 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone and terpyridine, and the organic solvent includes at least one of dichloromethane, chloroform, carbon tetrachloride, bromobenzene, and carbon disulfide.

[0006] In a second aspect, the present application provides a method for extracting lithium from a lithium precipitated mother liquor, comprising:

[0007] Providing the lithium extraction extractant as described above, and providing a lithium precipitation mother liquor, mixing the lithium extraction extractant with the lithium precipitation mother liquor, performing extraction treatment, and obtaining a mixed solution A;

[0008] The mixed solution A is allowed to stand for phase separation, and the lower oil phase is taken to obtain an extracted organic phase containing lithium-containing insoluble matter;

[0009] The extracted organic phase is filtered to obtain a lithium-containing solid complex.

[0010] In some embodiments, the extraction temperature of the extraction process is Tm, 20°C≤Tm≤50°C; preferably, 30°C≤Tm≤50°C.

[0011] In some embodiments, the extraction treatment time is tm, 10min≤tm≤30min; preferably, 20min≤tm≤30min.

[0012] In some embodiments, the concentration of lithium ions in the lithium precipitation mother solution is A, 2.13 g / L≤A≤2.65 g / L; the concentration of sodium ions in the lithium precipitation mother solution is B, 48.25 g / L≤B≤51.32 g / L;

[0013] In some embodiments, the pH of the lithium precipitation mother solution satisfies: 9≤pH≤14.

[0014] In some embodiments, providing the lithium extraction agent comprises: dissolving the solid solute in the organic solvent until saturation to form a uniform lithium extraction agent;

[0015] The dissolution temperature of the solute in the organic solvent is T0, the extraction temperature of the extraction treatment is Tm, and T0=Tm.

[0016] In some embodiments, filtering the extracted organic phase further comprises: obtaining an organic phase;

[0017] Providing the lithium extraction extractant includes: recycling the organic phase and using it as the organic solvent to dissolve the solute to prepare a new lithium extraction extractant.

[0018] In some embodiments, the extraction treatment includes: the volume ratio of the lithium extraction extractant to the lithium precipitation mother liquor is C, and the range of C is 1:3~3:1.

[0019] Based on the lithium extraction extractant and extraction method for lithium precipitated mother liquor of the embodiments of the present application, the lithium extraction extractant can be used to extract lithium from lithium precipitated mother liquor in a wide pH range. After entering the lithium extraction extractant, the lithium ions quickly complex with the solute in the lithium extraction extractant to form a solid phase. The mixed solution A after extraction only needs to be allowed to stand for phase separation. The lithium exists in the lithium-containing solid complex in the lower oil phase. The lithium-containing solid complex can be obtained by filtering the lower oil phase, and the residual sodium in the lithium-containing solid complex is small. The extraction method of the present application can omit the washing, stripping and other steps at the back end of the traditional extraction process, greatly shorten the extraction process flow, and save production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a flow chart of a method for extracting lithium from lithium precipitated mother liquor according to an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] An embodiment of the present application provides an extractant for extracting lithium from a lithium precipitation mother liquor. The lithium extractant includes a solute and an organic solvent. The solute includes at least one of 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraketone (TAPT) and terpyridine, and the organic solvent includes at least one of dichloromethane, chloroform, carbon tetrachloride, bromobenzene, and carbon disulfide.

[0024] When the lithium extraction agent of the embodiment of the present application is used to extract lithium from the lithium precipitation mother liquor, it can be used to extract lithium from the lithium precipitation mother liquor in a wide pH range. After entering the lithium extraction extractant, the lithium ions quickly complex with the solute in the lithium extraction extractant to form a solid phase (i.e., a lithium-containing solid complex). In addition, the organic solvent selected in the present application can not only dissolve the solute well, but also has a large specific gravity. The mixed solution A after extraction only needs to be left to stand for phase separation to separate the oil phase (i.e., the extracted organic phase) and the water phase. The water phase exists in the upper layer, the oil phase exists in the lower layer, the lithium exists in the lithium-containing solid complex of the lower oil phase, and the sodium exists in the upper water phase. Take the lower layer of oil, filter the lower oil phase to obtain the lithium-containing solid complex, and the residual amount of sodium in the lithium-containing solid complex is small. The extraction method of the present application can save the washing and stripping steps of the traditional extraction process, greatly shorten the extraction process flow, and save production costs. The organic phase obtained by filtering the lower oil phase can be recycled and used as an organic solvent to dissolve the solute again and prepare a new lithium extraction agent.

[0025] like Figure 1 As shown, the present application embodiment also provides a method for extracting lithium from lithium precipitated mother liquor, comprising:

[0026] Step S100, providing the lithium extraction extractant as described above, and providing a lithium precipitation mother liquor, mixing the lithium extraction extractant with the lithium precipitation mother liquor, performing extraction treatment, and obtaining a mixed solution A.

[0027] Step S200, allowing the mixed solution A to stand for phase separation, taking out the lower oil phase, and obtaining an extracted organic phase containing lithium-containing insoluble matter.

[0028] Step S300, filtering the extracted organic phase to obtain a lithium-containing solid complex.

[0029] The method for extracting lithium from lithium precipitated mother liquor in the embodiment of the present application can extract lithium from lithium precipitated mother liquor in a wider pH range by adopting the lithium extraction extractant as described above. The extracted lithium exists in the lithium-containing solid complex in solid form, thereby realizing lithium and sodium separation. After the extraction is completed, there is no need to go through traditional extraction processes such as washing and back extraction. Only the extracted organic phase needs to be filtered to obtain the lithium-containing solid complex and the organic phase. The organic phase can be regenerated for preparing a new lithium extraction extractant. The lithium extraction process is simple, the extraction process is shortened to a great extent, and the production cost is saved.

[0030] In some embodiments, providing an organic phase includes: dissolving a solid solute in an organic solvent until saturation to form a uniform organic phase. The solute in a saturated state can allow lithium to contact the solute more fully, thereby improving the extraction rate of lithium.

[0031] The dissolution temperature of the solute in the organic solvent is T0, the extraction temperature of the extraction treatment is Tm, and T0=Tm. In this way, during the extraction process, the stability of the solute and the organic solvent in the lithium extraction agent can be maintained.

[0032] In some embodiments, filtering the mixed solution A further comprises: obtaining an organic phase. Providing a lithium extraction agent comprises: using the organic phase as an organic solvent to dissolve the solute, so that all substances obtained after the extraction process can be utilized, no waste is discharged, and resources are saved.

[0033] In some embodiments, the extraction temperature of the extraction process is Tm, 20°C≤Tm≤50°C, for example, Tm can be 20°C, 25°C, 30°C, 40°C, 45°C, 50°C or any range thereof. In the above temperature range, the stability of the solute and the organic solvent in the lithium extraction agent can be maintained, and the solute and lithium can be more fully complexed to form a complex.

[0034] In some embodiments, the extraction treatment time is tm, 10min≤tm≤30min, for example, tm can be 10min, 15min, 20min, 25min, 30min or any range thereof. In this temperature range, lithium can be more fully contacted with the solute, thereby improving the extraction rate of lithium.

[0035] In some embodiments, stirring can be used during the extraction process to accelerate the entry of lithium into the solute and increase the efficiency of the solute and lithium forming a complex, wherein the stirring can be performed in a magnetic stirrer. The stirring speed of the extraction process is P, 80rpm≤P≤120rpm, for example, P can be 80rpm, 90rpm, 100rpm, 110rpm, 120rpm or any range thereof.

[0036] In some embodiments, the concentration of lithium ions in the lithium precipitation mother solution is A, 2.13 g / L≤A≤2.65 g / L, for example, A can be 2.13 g / L, 2.25 g / L, 2.38 g / L, 2.46 g / L, 2.55 g / L, 2.65 g / L or any range thereof.

[0037] In some embodiments, the concentration of sodium ions in the lithium precipitation mother liquor is B, 48.25 g / L≤B≤51.32 g / L. For example, B can be 48.25 g / L, 49.30 g / L, 49.88 g / L, 50.21 g / L, 50.80 g / L, 51.32 g / L or any range thereof.

[0038] In some embodiments, the pH of the lithium precipitation mother solution satisfies: 9≤pH≤14, for example, the pH may be 9, 10, 11, 12, 13, 14 or any range thereof. In the above pH range, the solute and the organic solvent in the lithium extraction agent can still maintain a relatively stable state, so that the solute can be fully complexed with lithium.

[0039] In some embodiments, the extraction process includes: the volume ratio of the lithium extraction extractant to the lithium precipitation mother liquor is C, and the range of C is 1:3~3:1. For example, C can be 1:3, 2:3, 3:3, 3:2, 3:1 or any range of the above two. By selecting the volume ratio C of the lithium extraction extractant to the lithium precipitation mother liquor within the above range, the lithium extraction extractant can more fully extract the lithium in the lithium precipitation mother liquor.

[0040] In order to more intuitively understand the lithium extraction effect of the method for extracting lithium from lithium precipitated mother liquor in the embodiment of the present application, the method for extracting lithium from lithium precipitated mother liquor in the present application is further described by way of examples below.

[0041] The lithium ion concentration A in the lithium precipitation mother solution selected in the following examples was measured by ICP-OES (inductively coupled plasma emission spectrometer) to be 2.65 g / L and the sodium ion concentration B to be 51.32 g / L.

[0042] Example 1

[0043] (1) Preparation of lithium extraction agent

[0044] TAPT is selected as the solute and dichloromethane is selected as the organic solvent. TAPT is dissolved in dichloromethane at 35° C. until it reaches a saturated state, thereby obtaining a lithium extracting agent.

[0045] (2) Extraction treatment

[0046] The lithium extraction agent and the lithium precipitation mother liquor were taken in a volume ratio of 1:1, and the pH of the lithium precipitation mother liquor was adjusted to 11 with a sodium hydroxide solution. The lithium precipitation mother liquor was added to the lithium extraction agent, and the mixture was extracted at a stirring speed of 120 rpm and a temperature of 35° C. for 20 minutes to obtain a mixed solution A.

[0047] (3) The mixed solution A is allowed to stand for phase separation, and an upper aqueous phase and a lower oil phase are separated. The lower oil phase is taken to obtain an extracted organic phase containing lithium-containing insoluble matter.

[0048] (4) Filtering the extracted organic phase containing lithium-containing insoluble matter to separate the insoluble matter and the organic phase, and taking the insoluble matter to obtain a lithium-containing solid complex.

[0049] Among them, the concentration of lithium ions in the upper aqueous phase is measured as m1, and the concentration of sodium ions is m2.

[0050] Lithium extraction rate = m1 / A*100%; sodium extraction rate = m2 / B*100%.

[0051] Example 2

[0052] The difference from Example 1 is that chloroform is selected as the organic solvent.

[0053] Example 3

[0054] The difference from Example 1 is that tetrachloromethane is selected as the organic solvent.

[0055] Example 4

[0056] The difference from Example 1 is that bromobenzene is selected as the organic solvent.

[0057] Example 5

[0058] The difference from Example 1 is that carbon disulfide is selected as the organic solvent.

[0059] Example 6

[0060] The difference from Example 1 is that terpyridine is selected as the solute.

[0061] Example 7

[0062] The difference from Example 6 is that chloroform is selected as the organic solvent.

[0063] Example 8

[0064] The difference from Example 6 is that tetrachloromethane is selected as the organic solvent.

[0065] Example 9

[0066] The difference from Example 6 is that bromobenzene is selected as the organic solvent.

[0067] Example 10

[0068] The difference from Example 6 is that carbon disulfide is selected as the organic solvent.

[0069] Embodiment 11

[0070] The difference from Example 2 is:

[0071] (1) In the preparation of the lithium extraction agent, TAPT is dissolved in chloroform at 20°C until saturated.

[0072] (2) In the extraction treatment, the lithium extraction agent and the lithium precipitation mother liquor are taken in a volume ratio of 3:1, and the pH of the lithium precipitation mother liquor is adjusted to 9, and the extraction is carried out at a temperature of 20° C. for 20 minutes to obtain a mixed solution.

[0073] Example 12

[0074] The difference from Example 11 is:

[0075] (2) In the extraction treatment, the lithium extraction agent and the lithium precipitation mother liquor are taken in a volume ratio of 1:3, and the pH of the lithium precipitation mother liquor is adjusted to 13, and the extraction is carried out at a temperature of 20° C. for 30 minutes to obtain a mixed solution.

[0076] Example 13

[0077] The difference from Example 11 is:

[0078] (2) During the extraction process, the pH of the lithium precipitation mother liquor was adjusted to 14, and the mixture was extracted at 20°C for 30 minutes to obtain a mixed solution.

[0079] Embodiment 14

[0080] The difference from Example 2 is:

[0081] (1) In the preparation of the lithium extraction agent, TAPT was dissolved in chloroform at 50°C until saturated.

[0082] (2) In the extraction treatment, the lithium extraction agent and the lithium precipitation mother liquor are taken in a volume ratio of 3:1, and the pH of the lithium precipitation mother liquor is adjusted to 9, and the extraction is carried out at a temperature of 50° C. for 20 minutes to obtain a mixed solution.

[0083] Embodiment 15

[0084] The difference from Example 14 is:

[0085] (2) In the extraction treatment, the lithium extraction agent and the lithium precipitation mother liquor are taken in a volume ratio of 1:3, and the pH of the lithium precipitation mother liquor is adjusted to 13, and the extraction is carried out at a temperature of 50° C. for 30 minutes to obtain a mixed solution.

[0086] Example 16

[0087] The difference from Example 14 is:

[0088] (2) During the extraction treatment, the pH of the lithium precipitation mother liquor was adjusted to 14, and the mixture was extracted at 50°C for 30 minutes to obtain a mixed solution.

[0089] Embodiment 17

[0090] The difference from Example 8 is that:

[0091] (1) In the preparation of the lithium extraction agent, terpyridine is dissolved in carbon tetrachloride at 20°C until saturated.

[0092] (2) In the extraction treatment, the lithium extraction agent and the lithium precipitation mother liquor are taken in a volume ratio of 3:1, and the pH of the lithium precipitation mother liquor is adjusted to 9, and the extraction is carried out at a temperature of 20° C. for 20 minutes to obtain a mixed solution.

[0093] Embodiment 18

[0094] The difference from Example 17 is that:

[0095] (2) In the extraction treatment, the lithium extraction agent and the lithium precipitation mother liquor are taken in a volume ratio of 1:3, and the pH of the lithium precipitation mother liquor is adjusted to 13, and the extraction is carried out at a temperature of 20° C. for 30 minutes to obtain a mixed solution.

[0096] Embodiment 19

[0097] The difference from Example 17 is that:

[0098] (2) During the extraction process, the pH of the lithium precipitation mother liquor was adjusted to 14, and the mixture was extracted at 20°C for 30 minutes to obtain a mixed solution.

[0099] Embodiment 20

[0100] The difference from Example 8 is that:

[0101] (1) In the preparation of the lithium extraction agent, terpyridine is dissolved in carbon tetrachloride at 50°C until saturated.

[0102] (2) In the extraction treatment, the lithium extraction agent and the lithium precipitation mother liquor are taken in a volume ratio of 3:1, and the pH of the lithium precipitation mother liquor is adjusted to 9, and the extraction is carried out at a temperature of 50° C. for 20 minutes to obtain a mixed solution.

[0103] Embodiment 21

[0104] The difference from Example 20 is:

[0105] (2) In the extraction treatment, the lithium extraction agent and the lithium precipitation mother liquor are taken in a volume ratio of 3:1, and the pH of the lithium precipitation mother liquor is adjusted to 13, and the extraction is carried out at a temperature of 50° C. for 30 minutes to obtain a mixed solution.

[0106] Embodiment 22

[0107] The difference from Example 20 is:

[0108] (2) During the extraction treatment, the pH of the lithium precipitation mother liquor was adjusted to 14, and the mixture was extracted at 50°C for 30 minutes to obtain a mixed solution.

[0109] The test parameters and experimental results of Examples 1 to 22 are shown in Table 1.

[0110] Table 1

[0111]

[0112] According to Examples 1 to 10 in Table 1, it can be seen that the solute of the lithium extraction agent is selected from at least one of 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraketone (TAPT) and terpyridine, and the organic solvent is selected from at least one of dichloromethane, chloroform, carbon tetrachloride, bromobenzene, and carbon disulfide, and a good lithium extraction rate can be obtained, and the sodium extraction rate is low, indicating that the lithium extraction method for lithium precipitation mother liquor of the embodiment of the present application can effectively separate the lithium and sodium in the lithium precipitation mother liquor.

[0113] It can be seen from Examples 11 and 13, 14 and 16, 17 and 19, and 20 and 22 that the higher the pH of the lithium precipitation mother liquor and the longer the extraction time, the higher the lithium extraction rate.

[0114] It can be seen from Examples 11 to 13, 14 to 16, 17 to 19, and 20 to 22 that the higher the volume ratio of the lithium extraction agent to the lithium precipitation mother liquor, the higher the lithium extraction rate, and the higher the extraction temperature Tm of the extraction treatment, the higher the lithium extraction rate.

[0115] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of this application, it should be understood that if the terms "upper", "lower", "left", "right", etc. indicate an orientation or position relationship based on the orientation or position relationship shown in the drawings, it is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0116] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for extracting lithium from lithium precipitated mother liquor, characterized in that: include: Providing a solute and an organic solvent, dissolving the solid solute in the organic solvent until saturation, and forming a uniform lithium extraction agent; the solute comprises at least one of 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone and terpyridine, and the organic solvent comprises at least one of dichloromethane, chloroform, carbon tetrachloride, bromobenzene, and carbon disulfide; Providing a lithium precipitation mother liquor, wherein the volume ratio of the lithium extraction extractant to the lithium precipitation mother liquor is C, and the range of C is 1:3~3:1, and the lithium extraction extractant is mixed with the lithium precipitation mother liquor, and an extraction treatment is performed to obtain a mixed solution A; The mixed solution A is allowed to stand for phase separation, and the lower oil phase is taken to obtain an extracted organic phase containing lithium-containing insoluble matter; Providing the lithium extraction extractant includes: dissolving the solid solute in the organic solvent until saturation to form a uniform lithium extraction extractant; Filtering the extracted organic phase to obtain a lithium-containing solid complex and an organic phase; Providing the lithium extraction extractant also includes: recycling the organic phase and using it as the organic solvent to dissolve the solute to prepare a new lithium extraction extractant.

2. The method for extracting lithium from lithium precipitated mother liquor according to claim 1, characterized in that: The extraction temperature of the extraction treatment is Tm, 20°C≤Tm≤50°C; The extraction treatment time is tm, 10min≤tm≤30min.

3. The method for extracting lithium from lithium precipitated mother liquor according to claim 2, characterized in that: 30℃≤Tm≤50℃; 20min≤tm≤30min.

4. The method for extracting lithium from lithium precipitated mother liquor according to claim 1, characterized in that: The concentration of lithium ions in the lithium precipitation mother solution is A, 2.13 g / L≤A≤2.65 g / L; The concentration of sodium ions in the lithium precipitation mother solution is B, 48.25 g / L≤B≤51.32 g / L.

5. The method for extracting lithium from lithium precipitated mother liquor according to claim 1, characterized in that: The pH of the lithium precipitation mother solution satisfies: 9≤pH≤14.

6. The method for extracting lithium from lithium precipitated mother liquor according to claim 1, characterized in that: The dissolution temperature of the solute in the organic solvent is T0, the extraction temperature of the extraction treatment is Tm, and T0=Tm.

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