Lithium extraction extractant and application method thereof

Abstract

The invention discloses a lithium extraction agent and an application method thereof. According to the formula of the lithium extraction agent, LIX54 is matched with isopropyl phenyl ketone, tributyl phosphate (TBP) is matched with tripropyl phosphate (TPP), sulfonated kerosene is matched with petroleum ether and n-heptane, absolute ethyl alcohol is matched with butyl acetate and isopropyl alcohol, and all the components are mixed according to a specific proportion to form a uniform system. The lithium extraction extractant is specially adapted to an oscillatory flow reinforced sleeve type reactor, the emulsification phenomenon in the extraction process can be effectively inhibited, the problem that the sleeve extraction efficiency is weakened is solved, two phases are clearly layered in the extraction process, a phase splitting section in a traditional extraction process is not needed, the technological process is greatly shortened, and the production cost is saved. The extraction agent is used for extracting lithium in the lithium-containing mother liquor, the lithium extraction rate can reach 99% or above, the reverse extraction rate can reach 98% or above, the mass transfer efficiency is remarkably improved, and the extraction agent is suitable for industrial lithium recovery of lithium-containing feed liquid such as salt lake brine and battery recovery wastewater.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgy and solvent extraction technology, specifically relating to a lithium extraction extractant specially adapted to an oscillating flow enhanced tubular reactor, and an application method for separating and extracting lithium from low-concentration lithium-containing liquid using this extractant. It is particularly suitable for efficient and low-cost lithium recovery from salt lake brine, battery recycling wastewater, geothermal brine, oil and gas field produced water, and industrial wastewater, solving the technical problems of poor compatibility and low mass transfer efficiency of existing extractants with oscillating flow reactors. Background Technology

[0002] Lithium is a core strategic resource for the new energy industry, and market demand continues to rise with the development of industries such as lithium batteries. The efficient recovery of low-concentration lithium-containing solutions, such as salt lake brine and battery recycling wastewater, has become a key research focus in the industry. Current mainstream lithium extraction technologies, such as crystallization, electrodialysis, and adsorption, suffer from long separation processes and high costs. While solvent extraction is flexible and adaptable, traditional tubular extractors have inherent drawbacks such as low mass transfer efficiency.

[0003] Oscillating flow enhancement technology can enhance mass transfer by forming eddies through oscillation, thus compensating for the shortcomings of shell-and-tube extractors. However, existing lithium extraction extractants are poorly compatible with this reactor, and suffer from problems such as insufficient selectivity, limited mass transfer rate, and easy emulsification. Moreover, a single extractant is difficult to achieve both high selectivity and high mass transfer efficiency for lithium. The synergistic extraction system also suffers from insufficient optimization of component ratio and poor synergy with the reactor. At the same time, impurities such as sodium and potassium in lithium-containing liquids are difficult to separate. Therefore, there is an urgent need to develop a dedicated lithium extraction extractant with strong compatibility and application methods. Summary of the Invention

[0004] This invention addresses the problems in existing technologies, such as poor compatibility between lithium extractants and oscillating flow enhanced shell-and-tube reactors, low mass transfer efficiency, insufficient lithium selectivity, easy emulsification, and weakened shell-and-tube efficiency. It provides a lithium extractant for oscillating flow enhanced shell-and-tube reactors and its application method, achieving efficient and high-purity lithium extraction from lithium-containing liquids. The process is easy to scale up and suitable for industrial production.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a lithium-ion extractant, based on a total system volume of 1L and standard conditions of 25°C, comprising the following components (by volume fraction, the sum of the volume fractions of each component is 100%): LIX54 and isopropyl phenyl ketone, wherein the volume fraction of LIX54 is 4%–8%, corresponding to a concentration of 0.122–0.195 mol / L (LIX54 molar mass approximately 320 g / mol, density approximately 0.98 g / mL), and the volume fraction of isopropyl phenyl ketone is 0.1%–0.5%, corresponding to a concentration of 0.01–0.05 mol / L (isopropyl phenyl ketone molar mass approximately 226 g / mol, density approximately 0.92 g / mL); the isopropyl phenyl ketone is an inert component with similar physical properties to LIX54, does not participate in the lithium-ion extraction reaction, and is only used to improve the stability of the system and prevent LIX54 from crystallizing out in an oscillating environment; Tributyl phosphate (TBP) and tripropyl phosphate (TPP) are used, wherein the volume fraction of TBP is 8%–12%, corresponding to a concentration of 0.291–0.437 mol / L (TBP molar mass 266.34 g / mol, density 0.97 g / mL), and the volume fraction of TPP is 0.05%–0.3%, corresponding to a concentration of 0.005–0.03 mol / L (TPP molar mass 220.28 g / mol, density 0.92 g / mL); TPP is an inert component with a structure similar to TBP, does not have a co-extraction function, and is only used to prevent the crystallization of a single component in the system; The mixture comprises sulfonated kerosene, petroleum ether, and n-heptane, wherein the volume fraction of sulfonated kerosene is 50%–80%, the volume fraction of petroleum ether is 10%–50%, and the volume fraction of n-heptane is 0.2%–2%. The sulfonated kerosene is used to provide an acidic environment to promote the lithium-ion extraction reaction, the petroleum ether is used to suppress emulsification during the extraction process (to adapt to the oscillating environment of the oscillating flow reactor and avoid emulsification caused by oscillation), and the n-heptane is an inert diluent component that does not affect the functions of the former two components, can reduce the viscosity of the system, reduce the mass transfer resistance of the oscillating flow sleeve reactor, and thus reduce the weakening of the sleeve extraction efficiency. The mixture comprises anhydrous ethanol, butyl acetate, and isopropanol, wherein the volume fraction of anhydrous ethanol is 2%–4%, the volume fraction of butyl acetate is 3%–6%, and the volume fraction of isopropanol is 2%–4%. The anhydrous ethanol and butyl acetate work synergistically to promote the transfer of the complex formed by lithium ions with the extractant and co-extractant to the oil phase, thereby improving the mass transfer efficiency. Isopropanol is an inert modifying component that does not interfere with the complex transfer process and is only used to improve the homogeneity of the system.

[0006] The preparation method of the lithium-ion extractant of the present invention includes the following steps: weighing each component in sequence according to the above volume fraction, adding them to a container, and magnetically stirring at 25-35°C for 15-25 minutes until the mixture is uniform and transparent, thereby obtaining the lithium-ion extractant; preferably, the stirring temperature is 30°C and the stirring time is 20 minutes. This preparation method is simple, easy to operate, and suitable for industrial mass production.

[0007] This invention also provides a method for applying the above-mentioned lithium extraction agent, using an oscillating flow enhanced shell-and-tube reactor, comprising the following steps: (1) Provide the above-mentioned lithium extraction agent, and provide lithium-containing mother liquor (lithium ion concentration 0.56-0.65 g / L, sodium ion concentration 42.68-45.27 g / L, pH=10-14). (2) The lithium extraction agent and the lithium-containing mother liquor are passed into an oscillating flow enhanced sleeve extractor for extraction treatment. The extracted lithium extraction agent A can be obtained without phase separation. The volume ratio of the lithium extraction agent to the lithium-containing mother liquor is 1:3-3:1, the oscillation frequency is 1Hz-3Hz, the amplitude is 2mm-14mm, the Reynolds number Ren of the two-phase flow in the reactor is 0.5-5, and the reactor length is 50cm-300cm. The oscillating flow sleeve reactor is equipped with a spiral internal component. The internal component is made of stainless steel, the inner tube of the reactor is a PTFE hollow fiber membrane, and the outer tube is made of FEP material. (3) Add 0.5-2 mol / L hydrochloric acid solution to the lithium extraction extractant A after extraction and perform back-extraction. The back-extraction ratio (organic phase: aqueous phase, volume ratio) is 1:1-3:1, the back-extraction temperature is 25℃-45℃, and the back-extraction time is 2min-8min. After back-extraction, back-extraction solution B is obtained. (4) Concentrate and crystallize the back-extraction solution B to obtain the desired lithium-containing product.

[0008] The beneficial effects of this invention are as follows: 1. High adaptability: Specifically designed for oscillating flow enhanced shell-and-tube reactors, it effectively reduces the weakening of shell-and-tube extraction efficiency by inhibiting emulsification with petroleum ether and reducing system viscosity with n-heptane, thus solving the technical problem of poor compatibility between existing extractants and oscillating flow reactors. 2. High extraction efficiency: The synergistic effect of LIX54 and TBP, combined with the promoting effect of phase modifiers, achieves a lithium extraction rate of over 99% and a back-extraction rate of over 98%. The mass transfer coefficient is more than twice that of traditional extraction systems (e.g., the mass transfer coefficient in Example 2 is 2.48458 × 10⁻⁶). -6 m / s, much higher than the comparative example of 8.394 × 10 -7 m / s); 3. Simplified process: The two phases are clearly separated during the extraction process, eliminating the need for the phase separation section in traditional extraction processes, which can shorten the process flow by more than 30% and significantly reduce production costs; 4. Good stability: By adding inert similar components (isopropyl phenyl ketone, TPP, etc.), the crystallization of effective components is avoided, and the cycle stability of the extractant is improved. After being recycled more than 10 times, the extraction rate still remains above 95%. 5. Wide range of applications: It is suitable for various lithium-containing liquids such as salt lake brine and battery recycling wastewater, and is especially suitable for lithium extraction from low-concentration, high-impurity (such as high sodium) lithium-containing liquids, making it highly practical. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0010] Figure 1 is a schematic diagram of the structure of the oscillating flow sleeve reactor of the present invention; In the diagram: 1 - Lithium-containing aqueous phase collection tank, 2 - Shell-and-tube reactor, 3 - Spiral internal component (stainless steel), 4 - Inner tube (PTFE hollow fiber membrane), 5 - Outer tube (FEP), 6 - Shaking device (diaphragm pump), 7 - Organic phase collection tank, 8 - Flow pump, 9 - Back pressure valve, 10 - Pressure gauge, 11 - Lithium-containing aqueous phase raw material, 12 - Organic phase raw material. Detailed Implementation

[0011] The present invention will be further described in detail below through specific embodiments, and the scope of protection of the present invention is not limited to the following embodiments.

[0012] Example 1 Preparation of lithium extractant

[0013] Weigh out 6 ml of LIX54 (98% purity, Sinopharm Group) (5% volume fraction, corresponding to a concentration of 0.184 mol / L), 0.3 ml of isopropyl phenyl ketone (99% purity, Aladdin) (0.25% volume fraction, corresponding to a concentration of 0.03 mol / L), 12 ml of tributyl phosphate (TBP, 99% purity, Sinopharm Group) (10% volume fraction, corresponding to a concentration of 0.437 mol / L), and 0.18 ml of tripropyl phosphate (TPP, 98% purity, Aladdin) (0.15% volume fraction, corresponding to a concentration of 0.018 mol / L). 66 ml (volume fraction 55%) of sulfonated kerosene (industrial grade, purity 95%), 24 ml (volume fraction 20%) of petroleum ether (60-90℃, purity 99%), 0.72 ml (volume fraction 0.6%) of n-heptane (purity 99%, Aladdin); 3.6 ml (volume fraction 3%) of anhydrous ethanol (purity 99.7%), 3.6 ml (volume fraction 3%) of butyl acetate (purity 99%), and 3.6 ml (volume fraction 3%) of isopropanol (purity 99.7%); the total volume of the above components is 120 ml, and the sum of the volume fractions of each component is 100%.

[0014] The above components were added to a beaker in sequence and magnetically stirred at 30°C for 20 minutes until the mixture was homogeneous and transparent, thus obtaining the lithium extraction agent of the present invention.

[0015] Example 2 Extraction and separation of lithium

[0016] The lithium extraction extractant prepared in Example 1 was used to recover lithium from the lithium-containing mother liquor in an oscillating flow enhanced tubular reactor. The specific steps are as follows: 1. Select a lithium-containing mother liquor with a lithium ion concentration of 0.6 g / L and a sodium ion concentration of 43 g / L as the lithium-containing aqueous phase, and adjust the pH value to 13; 2. The lithium-containing mother liquor is fed into the outer tube of the oscillating flow sleeve reactor, and the lithium extraction extractant is fed into the inner tube of the reactor. The countercurrent flow mode is adopted, and the ratio (organic phase: aqueous phase, volume ratio) is controlled at 1:1, the Reynolds number of the aqueous phase is Ren=0.653, and the reactor length is 100cm. 3. Turn on the oscillation device (diaphragm pump), and control the oscillation frequency to 1.5Hz and the amplitude to 11.925mm; 4. After extraction equilibrium is reached, the loaded organic phase and the raffinate aqueous phase are obtained from the two-phase outlet; 5. Use 1 mol / L hydrochloric acid solution as the back-extraction agent and back-extract it with the supported organic phase at a ratio of 1:1. The back-extraction temperature is 25℃ and the back-extraction time is 5 minutes. The back-extracted organic phase is washed and recycled.

[0017] The lithium extraction rate in this embodiment was 99.2%, and the mass transfer coefficient was 2.48458 × 10⁻⁶. -6 With a speed of m / s and a back-extraction rate of 98.3%, there was no emulsification during the extraction process. After the reactor had been running for 24 hours, the extraction efficiency decreased by only 1.2%, demonstrating good adaptability and stability.

[0018] Example 3: Effect of different oscillation parameters on extraction efficiency

[0019] The lithium extraction extractant prepared in Example 1 was used. A lithium-containing mother liquor with a lithium ion concentration of 0.6 g / L and a sodium ion concentration of 43 g / L was used as the lithium-containing aqueous phase. The pH was adjusted to 13, the phase ratio was 1:1, the Reynolds number of the aqueous phase was Ren = 0.653, and the reactor length was 100 cm. The effects of different oscillation frequencies and amplitudes on the lithium extraction rate were investigated. The results are shown in the table below.

[0020] The results show that increasing the oscillation frequency and amplitude can significantly improve the lithium extraction rate, and the extractant of the present invention does not exhibit emulsification under different oscillation parameters. Considering the energy consumption and extraction effect in industrial production, the preferred oscillation frequency is 1.5 Hz and the amplitude is 11.925 mm.

[0021] Comparative Example

[0022] Control Group 1: Extraction experiments were conducted using LIX54+TBP+TPP extractant (LIX54 volume fraction 5%, TBP volume fraction 10%, TPP volume fraction 0.15%, isopropyl phenyl ketone-free, sulfonated kerosene volume fraction 55.25%, petroleum ether volume fraction 20%, n-heptane volume fraction 0.6%, anhydrous ethanol volume fraction 3%, butyl acetate volume fraction 3%, isopropanol volume fraction 3%) in an oscillating flow enhanced tubular reactor under the conditions of Example 2.

[0023] Testing showed that the lithium extraction rate was 94.5% and the mass transfer coefficient was 1.52 × 10⁻⁶. -6 m / s, the back-extraction rate was 96.2%, there was no emulsification during the extraction process, and the shell efficiency decreased by 1.2% after the reactor had been running for 24 hours.

[0024] Control Group 2: Extraction experiments were conducted using LIX54 + TBP + isopropyl phenyl ketone extractant (LIX54 volume fraction 5%, TBP volume fraction 10%, isopropyl phenyl ketone volume fraction 0.25%, no TPP, sulfonated kerosene volume fraction 55.15%, petroleum ether volume fraction 20%, n-heptane volume fraction 0.6%, anhydrous ethanol volume fraction 3%, butyl acetate volume fraction 3%, isopropanol volume fraction 3%) in an oscillating flow enhanced tubular reactor under the conditions of Example 2.

[0025] Testing showed that the lithium extraction rate was 95.9% and the mass transfer coefficient was 1.64 × 10⁻⁶. -6 The extraction rate was 96.5% with a flow rate of m / s. No emulsification occurred during the extraction process. After the reactor had been running for 24 hours, the efficiency of the casing decreased by 1.2%.

[0026] Control group 3: Extraction experiments were conducted using LIX54+TBP extractant (LIX54 volume fraction 5%, TBP volume fraction 10%, no isopropyl phenyl ketone, no TPP, sulfonated kerosene volume fraction 55.4%, petroleum ether volume fraction 20%, n-heptane volume fraction 0.6%, anhydrous ethanol volume fraction 3%, butyl acetate volume fraction 3%, isopropanol volume fraction 3%) in an oscillating flow enhanced shell-and-tube reactor under the conditions of Example 2.

[0027] Testing showed that the lithium extraction rate was 92.5% and the mass transfer coefficient was 1.31 × 10⁻⁶. -6 The extraction rate was 94.6% with a flow rate of m / s. No emulsification occurred during the extraction process. After the reactor had been running for 24 hours, the efficiency of the casing decreased by 1.2%.

[0028] Control group 4: Extraction experiments were conducted using LIX54+TBP extractant (LIX54 volume fraction 5%, TBP volume fraction 10%, isopropyl phenyl ketone volume fraction 0.25%, TPP volume fraction 0.15%, sulfonated kerosene volume fraction 75%, petroleum ether-free, n-heptane volume fraction 0.6%, anhydrous ethanol volume fraction 3%, butyl acetate volume fraction 3%, isopropanol volume fraction 3%) in an oscillating flow enhanced shell-and-tube reactor under the conditions of Example 2.

[0029] Testing showed that the lithium extraction rate was 94.5% and the mass transfer coefficient was 1.52 × 10⁻⁶. -6 The extraction rate was 95.9% with a flow rate of m / s. Slight emulsification occurred during the extraction process. After the reactor had been running for 24 hours, the efficiency of the casing decreased by 9.3%.

[0030] Control group 5: Extraction experiments were conducted using LIX54+TBP extractant (LIX54 volume fraction 5%, TBP volume fraction 10%, isopropyl phenyl ketone volume fraction 0.25%, TPP volume fraction 0.15%, sulfonated kerosene volume fraction 55.6%, petroleum ether volume fraction 20%, no n-heptane, anhydrous ethanol volume fraction 3%, butyl acetate volume fraction 3%, isopropanol volume fraction 3%) in an oscillating flow enhanced shell-and-tube reactor under the conditions of Example 2.

[0031] Testing showed that the lithium extraction rate was 94.1% and the mass transfer coefficient was 1.48 × 10⁻⁶. -6 The extraction rate was 95.9% with a flow rate of m / s. No emulsification occurred during the extraction process. After the reactor had been running for 24 hours, the efficiency of the casing decreased by 2.2%.

[0032] Control group 6: The lithium extraction extractant prepared in Example 1 was used to conduct extraction experiments in a conventional tubular reactor without an oscillation device or spiral internal components, under the conditions of Example 2.

[0033] Testing revealed that the lithium extraction rate was only 82.8%, and the mass transfer coefficient was 8.394 × 10⁻⁶. -7 The mass transfer efficiency was 97.0% with a rate of m / s and no emulsification, but the mass transfer efficiency was significantly lower than that of Example 2.

[0034] Comparative results show that the lithium extraction agent of this invention, combined with the oscillating flow enhancement technology, can significantly improve lithium recovery efficiency and mass transfer efficiency, while solving the problems of emulsification and reduced casing efficiency, which is significantly better than the combination of conventional extractants and traditional reactors.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Those skilled in the art, based on the teachings provided in this invention, can make various modifications and improvements to the invention, all of which should fall within the protection scope of this invention. The scope of protection claimed by this invention should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A lithium-ion extractant, characterized in that, Under standard conditions at 25°C, the composition, by volume fraction, includes the following components: LIX54 and isopropyl phenyl ketone, wherein the volume fraction of LIX54 is 4%–8% and the volume fraction of isopropyl phenyl ketone is 0.1%–0.5%; Tributyl phosphate (TBP) and tripropyl phosphate (TPP), wherein the volume fraction of TBP is 8%–12% and the volume fraction of TPP is 0.05%–0.3%; The mixture contains sulfonated kerosene, petroleum ether, and n-heptane, wherein the volume fraction of sulfonated kerosene is 50%–80%, the volume fraction of petroleum ether is 10%–50%, and the volume fraction of n-heptane is 0.2%–2%. Anhydrous ethanol, butyl acetate, and isopropanol, wherein the volume fraction of anhydrous ethanol is 2%–4%, the volume fraction of butyl acetate is 3%–6%, and the volume fraction of isopropanol is 2%–4%; The sum of the volume fractions of each component is 100%.

2. The lithium-ion extractant according to claim 1, characterized in that, The volume fraction of LIX54 is 5%, and the volume fraction of isopropyl phenyl ketone is 0.25%.

3. The lithium-ion extractant according to claim 1, characterized in that, The volume fraction of TBP is 10%, and the volume fraction of TPP is 0.15%.

4. The lithium-ion extractant according to claim 1, characterized in that, The volume fraction of sulfonated kerosene is 50%–60%, the volume fraction of petroleum ether is 15%–25%, and the volume fraction of n-heptane is 0.4%–0.8%.

5. The lithium-ion extractant according to claim 1, characterized in that, The volume fraction of anhydrous ethanol is 2%–3%, the volume fraction of butyl acetate is 3%–5%, and the volume fraction of isopropanol is 1.5%–3.5%.

6. The method for preparing the lithium-ion extractant according to any one of claims 1 to 5, characterized in that, Includes the following steps: Weigh each component in the specified proportions and add them to a container. Stir magnetically at 25–35°C for 15–25 minutes until the mixture is homogeneous and transparent to obtain the lithium-ion extractant.

7. The preparation method according to claim 6, characterized in that, The stirring temperature is 30℃ and the stirring time is 20 minutes.

8. The application of the lithium-ion extractant according to any one of claims 1 to 5 in lithium extraction in an oscillating flow-enhanced shell-and-tube reactor, characterized in that, The application targets lithium-containing mother liquor. The lithium-ion extractant and lithium-containing mother liquor are passed into an oscillating flow enhanced shell-and-tube reactor, which can complete the extraction without phase separation and can reduce the weakening of the shell-and-tube extraction efficiency.

9. The application according to claim 8, characterized in that, The oscillating flow enhanced sleeve reactor is equipped with a stainless steel spiral internal component, with the inner tube being a PTFE hollow fiber membrane and the outer tube being made of FEP material. During extraction, the volume ratio of lithium-ion extractant to lithium-containing mother liquor is 1:3 to 3:1, the oscillation frequency is 1 to 3 Hz, the amplitude is 2 to 14 mm, the Reynolds number of the aqueous phase in the reactor is 0.5 to 5, and the reactor length is 50 to 300 cm.

10. The application according to claim 8, characterized in that, The lithium-containing mother liquor has a lithium ion concentration of 0.56–0.65 g / L, a sodium ion concentration of 42.68–45.27 g / L, and a pH of 10–14.

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