Method for comprehensive utilization of lithium-containing brine

Abstract

The present application relates to the field of lithium ion enrichment and extraction of lithium-containing energy mineral resources, and particularly relates to a method for comprehensive utilization of lithium-containing brine. The method comprises the following steps: adding NaAlO2 solution into the lithium-containing brine, adjusting the pH to be acidic (pH=4.5-6.5) to realize selective separation of lithium ions; then separating calcium and magnesium ions in the form of step-by-step precipitation, and separating sodium and potassium ions in the form of crystallization. The method is not only beneficial to the front-end selective separation of lithium resources in the brine, but also beneficial to the comprehensive utilization of calcium, magnesium, potassium and other resources in the brine.

Description

Technical Field

[0001] This invention relates to the field of lithium ion enrichment and extraction from lithium-containing energy minerals, and particularly to a method for the comprehensive utilization of lithium-containing brine. Background Technology

[0002] With the accelerated global energy structure transformation, the demand for lithium resources from the new energy industry is experiencing explosive growth. Lithium and its compounds, as key components of energy storage materials, have become strategic resources supporting the development of electric vehicles, portable electronic devices, and large-scale energy storage systems. my country possesses abundant lithium-bearing brine resources, and their green and efficient development is of great practical significance for alleviating lithium resource supply pressure and reducing dependence on imports. Compared with hard-rock lithium deposits, brine-type lithium resources are widely distributed, have lower energy consumption for extraction, and offer a significant competitive advantage in lithium extraction costs. Therefore, the comprehensive utilization of liquid lithium resources such as salt lake brines, underground brines, and associated brine from oil fields has become a core issue of common concern to both academia and industry in recent years.

[0003] Currently, the mainstream technical routes for lithium extraction from brine can be summarized into three major stages: evaporation and concentration, stepwise impurity removal, and precipitation conversion. Specific methods encompass unit operations such as evaporation crystallization, chemical precipitation, solvent extraction, selective adsorption, and membrane separation. The basic logic of these processes is "concentration and desalination first, followed by lithium extraction and impurity removal," placing lithium recovery at the end of the entire process. However, this process architecture has revealed inherent flaws in practical applications: on the one hand, during the evaporation and salt precipitation process, a large number of lithium ions are ineffectively separated due to entrainment in the mother liquor from the precipitated salts, resulting in significant one-time lithium loss; on the other hand, with the increase in concentration factor, the concentration of calcium and magnesium ions in the brine increases simultaneously, significantly increasing the consumption of chemical reagents and operational load required for subsequent calcium and magnesium removal. Furthermore, during the precipitation process to remove calcium and magnesium, lithium ions are easily co-precipitated or physically entrained, further exacerbating lithium dispersion losses, making it difficult to overcome the technical bottleneck in overall lithium recovery rate. Especially under conditions of low original lithium concentration, the energy and material consumption for lithium extraction rises sharply, leading to particularly significant economic degradation.

[0004] In view of this, there is an urgent need to explore a new separation path that can avoid the drawbacks of the traditional "concentration before lithium extraction" process, starting from the source of the process logic. This aims to achieve effective separation of lithium and impurity ions in the early stages, reduce lithium loss in intermediate stages, and improve lithium recovery efficiency. This invention is proposed under this technical requirement, aiming to provide an economically feasible and easily industrially implementable new solution for the efficient utilization of low-concentration lithium-containing brine.

[0005] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the inventors studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0006] This invention relates to the field of lithium ion enrichment and extraction from lithium-containing energy minerals, and particularly to a method for the comprehensive utilization of lithium-containing brine.

[0007] To address the aforementioned technical problems, one objective of this invention is to provide a method for the comprehensive utilization of lithium-containing brine, comprising the following steps: (1) Sodium aluminate (NaAlO2) is mixed with water and stirred at 100~150℃ until dissolved. After cooling, a sodium aluminate solution is obtained. (2) Add sodium aluminate solution to lithium-containing raw brine, adjust pH to 4.5~6.5, stir reaction at room temperature, filter and wash to obtain solid phase 1# and brine 1#, solid phase 1# is aluminum lithium layered hydroxide; (3) Mix solid phase 1# with water, shake and filter to obtain solid phase 2# and filtrate A; (4) After treating filtrate A with a divalent cation exchange resin, the solution is evaporated and concentrated, and sodium carbonate solution is added to carry out a precipitation reaction to obtain lithium carbonate; (5) Add sodium sulfate solution to brine 1#, stir and react, then filter to obtain solid phase 3# and brine 2#; (6) Add sodium hydroxide solution to brine 2# to adjust the pH to 12~13, stir and react, then filter to obtain solid phase 4# and brine 3#; (7) Mix solid phase 2# with sodium hydroxide solution and stir at 100~150℃ until dissolved. The resulting solution is returned to step (1) for recycling.

[0008] According to a preferred embodiment, in step (1), the mass ratio of sodium aluminate to water is 5~10:100. Preferably, the mass ratio of sodium aluminate to water is 5:100. The mass ratio of sodium aluminate to water is 8:100. The mass ratio of sodium aluminate to water is 10:100.

[0009] According to a preferred embodiment, in step (2), the volume ratio of sodium aluminate solution to lithium-containing primary halogen is 8-15:1000. Preferably, the volume ratio of sodium aluminate solution to lithium-containing primary halogen is 8:1000. Alternatively, the volume ratio of sodium aluminate solution to lithium-containing primary halogen is 15:1000. Or, the volume ratio of sodium aluminate solution to lithium-containing primary halogen is 10:1000.

[0010] According to a preferred embodiment, in step (2), the stirring reaction time is 3 to 6 hours.

[0011] According to a preferred embodiment, in step (3), the mass-to-volume ratio of solid phase 1# to water is 1:10~20. Preferably, the mass-to-volume ratio of solid phase 1# to water is 1:10. The mass-to-volume ratio of solid phase 1# to water is 1:15. The mass-to-volume ratio of solid phase 1# to water is 1:20.

[0012] According to a preferred embodiment, in step (3), the oscillation time is 4 to 8 hours.

[0013] According to a preferred embodiment, in step (4), the divalent cation exchange resin used to remove residual calcium and magnesium ions in filtrate A is any one of D401 resin, D418 resin, Amberlite IRC 748 resin, Purolite S940 resin, and Lewatit TP 208 resin. Preferably, the divalent cation exchange resin is D418 resin.

[0014] According to a preferred embodiment, in steps (4) and (5), the sodium carbonate solution is a saturated sodium carbonate solution.

[0015] According to a preferred embodiment, in step (5), solid phase 3# is calcium sulfate. Preferably, in step (5), the stirring reaction time is 3~6 h.

[0016] According to a preferred embodiment, in step (6), the concentration of the sodium hydroxide solution is 0.5~1.0 mol / L. Preferably, the concentration of the sodium hydroxide solution is 0.5 mol / L. Alternatively, the concentration of the sodium hydroxide solution is 0.8 mol / L. Or, the concentration of the sodium hydroxide solution is 1.0 mol / L.

[0017] According to a preferred embodiment, in step (6), solid phase 4# is magnesium hydroxide.

[0018] According to a preferred embodiment, in step (6), the stirring reaction time is 3 to 6 hours.

[0019] According to a preferred embodiment, in step (7), the concentration of the sodium hydroxide solution is 10~50 g / L. Preferably, the amount of sodium hydroxide solution used is 8~15 mL.

[0020] One objective of this invention is to provide a method for selectively separating lithium ions at the front end of lithium-containing brine, comprising the following steps: (1) Mix sodium aluminate with water and stir at 100~150℃ until dissolved. After cooling, a sodium aluminate solution is obtained. (2) Add sodium aluminate solution to lithium-containing raw brine, adjust pH to 4.5~6.5, stir reaction at room temperature, filter and wash to obtain lithium-containing solid phase and delithiated brine, the lithium-containing solid phase is aluminum lithium layered hydroxide; (3) Mix the lithium-containing solid phase with water, shake and filter to obtain lithium-containing filtrate and aluminum hydroxide solid phase.

[0021] The beneficial effects of this technical solution are: 1. Selective lithium separation at the front end reduces lithium dispersion loss. This invention employs a front-end lithium extraction process logic, directly adding sodium aluminate solution to the lithium-containing raw brine that has not been purified. Under acidic conditions, lithium ions are fixed in the solid phase in the form of lithium aluminum layered hydroxide (LiCl·2Al(OH)3·nH2O) through reaction adsorption, achieving early separation of lithium ions from calcium, magnesium, sodium, potassium, and other ions. This avoids the dispersion loss of lithium ions caused by evaporation salt entrainment and calcium and magnesium co-precipitation in the existing technology of first concentrating and then extracting lithium.

[0022] 2. Strong adaptability to low-lithium, high-calcium, and high-magnesium brines The lithium ion concentration used in this invention is only 6.3 mg / L, while the calcium ion concentration is 5452.6 mg / L and the magnesium ion concentration is 7954.8 mg / L, with calcium and magnesium concentrations being much higher than lithium. Under these conditions, the lithium ion concentration in brine #1 after the reaction in Example 3 decreased to 0.5 mg / L, in Example 1 it decreased to 0.7 mg / L, and in Example 2 it decreased to 0.9 mg / L, demonstrating a significant lithium ion separation effect. Comparative Example 3 shows that when the pH is controlled at 10, the lithium ion concentration in brine #1 is 6.1 mg / L, with almost no separation, further confirming the crucial role of reaction adsorption under acidic conditions in the front-end separation of lithium ions.

[0023] 3. Calcium and magnesium are recovered in stages to achieve comprehensive utilization of brine. After separating lithium at the front end, this invention adds sodium sulfate to brine 1# to precipitate and separate calcium ions to obtain calcium sulfate (solid phase 3#), and then adds sodium hydroxide to brine 2# to precipitate and separate magnesium ions to obtain magnesium hydroxide (solid phase 4#). This realizes the stepwise recovery of calcium and magnesium resources in the brine and creates conditions for the subsequent separation and utilization of sodium and potassium ions.

[0024] 4. Sodium aluminate can be recycled and reused. This invention dissolves the aluminum hydroxide solid phase (solid phase 2#) after water washing and desorption in sodium hydroxide solution at 100~150℃, and the resulting solution is returned to the sodium aluminate solution preparation step for recycling. This achieves the recovery and reuse of reaction reagents to a certain extent and reduces reagent consumption.

[0025] 5. The process is simple, the cost is low, and it is easy to implement. The reagents used in this invention are common chemical reagents such as sodium aluminate, sodium sulfate, and sodium hydroxide. The core reaction is carried out at room temperature. Only the solution preparation and reagent regeneration steps require heating. The process route is simple, the operating load is low, and it has the potential for environmental protection and industrial implementation. Attached Figure Description

[0026] Figure 1 This is a process flow diagram of the present invention; Figure 2 The XRD pattern of solid phase 1# in step (1) of Example 3; Figure 3 The XRD pattern of Li2CO3 in step (4) of Example 3; Figure 4 The XRD pattern of calcium sulfate in step (5) of Example 3; Figure 5 The image shows the XRD pattern of magnesium hydroxide from step (6) in Example 3. Detailed Implementation

[0027] In the description of this invention, terminology is used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0028] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the materials, reagents or instruments used, unless otherwise specified by the manufacturer, are all commercially available reagents and materials; the conditions not specified in the examples are all carried out according to conventional conditions or conditions recommended by the manufacturer. At the same time, the present invention does not limit the source of the raw materials used. Unless otherwise specified, the raw materials used in the present invention are all commercially available products in this technical field.

[0029] The main cation composition of the real brine (raw brine) used in this technology is shown in Table 1.

[0030] Table 1

[0031] To address the common problem in existing brine lithium extraction processes that employ a downstream route of first concentrating and desalting, followed by lithium extraction and impurity removal, lithium ions are ineffectively separated during evaporation and salt precipitation because they are entrained in the mother liquor. Furthermore, lithium ions are easily co-precipitated or physically entrained during subsequent calcium and magnesium removal processes, leading to low lithium recovery rates, especially with a sharp increase in energy and material consumption when the original brine lithium concentration is low. This invention provides a method for the comprehensive utilization of lithium-containing brine. This method employs a front-end lithium extraction approach, achieving selective separation of lithium ions from the original brine by directly adding sodium aluminate solution and controlling the reaction conditions, while simultaneously recovering calcium and magnesium resources stepwise and recycling the reaction reagents.

[0032] Example 1 like Figure 1 As shown, a method for extracting lithium from high-calcium lithium-containing brine includes the following steps: Step 1: Add 80 g of sodium aluminate to each liter of water and mix. Stir at 130°C until fully dissolved, then cool to room temperature for later use.

[0033] Step 2: Add 12 mL of sodium aluminate solution from Step 1 to 1000 mL of the original brine, adjust the pH to 5.2, stir at room temperature for 5 hours, vacuum filter, wash, and dry the solid phase at 60℃ to constant weight, labeling it as solid phase 1#, and the liquid phase as brine 1# for later use. Analysis showed that Li... + The concentration is 0.7 mg / L, Ca 2+ The concentration was 5450.8 mg / L, Mg 2+ The concentration was 7950.6 mg / L.

[0034] Step 3: Mix solid phase 1# with deionized water at a ratio of 1 g: 15 mL, shake for 6 h, dry the filtered solid phase at 60℃ to constant weight, and record it as solid phase 2#. Record the filtrate as filtrate A for later use.

[0035] Step 4: After passing filtrate A through divalent cation exchange resin D418 (to remove residual calcium and magnesium ions), the solution is concentrated by evaporation at 80°C and normal pressure. Saturated sodium carbonate solution is added, and after precipitation reaction, Li2CO3 product is obtained.

[0036] Step 5: Add saturated sodium sulfate solution to brine 1#, stir and react at room temperature for 3 hours, then filter to obtain solid phase 3# and brine 2#.

[0037] Step 6: Add 0.8 mol / L NaOH solution to brine 2# to adjust the pH to 12.5, stir and react at room temperature for 4 hours, and obtain solid phase 4# and brine 3# after filtration and washing.

[0038] Step 7: Stir solid phase 2# and 12 mL of 30 g / L NaOH solution at 130℃ until completely dissolved. The filtrate is recorded as solution a and returned to step 1 for recycling as a reaction solution.

[0039] Example 2 A method for extracting lithium from high-calcium lithium-containing brine includes the following steps: Step 1: Add 50 g of sodium aluminate to each liter of water and mix. Stir at 125°C until fully dissolved, then cool to room temperature for later use.

[0040] Step 2: Add 10 mL of sodium aluminate solution from Step 1 to 1000 mL of the original brine, adjust the pH to 5.0, stir at room temperature for 4 h, vacuum filter, wash, and dry the solid phase at 60℃ to constant weight, labeling it as solid phase 1#, and the liquid phase as brine 1# for later use. Analysis showed that Li... + The concentration was 0.9 mg / L, Ca 2+ The concentration was 5451.6 mg / L, Mg 2+ The concentration was 7948.8 mg / L.

[0041] Step 3: Mix solid phase 1# with deionized water at a ratio of 1 g: 10 mL, shake for 5 h, dry the filtered solid phase at 60℃ to constant weight, and record it as solid phase 2#. Record the filtrate as filtrate A for later use.

[0042] Step 4: After passing filtrate A through divalent cation exchange resin D418 (to remove residual calcium and magnesium ions), the solution is concentrated by evaporation at 80°C and normal pressure. Saturated sodium carbonate solution is added, and after precipitation reaction, Li2CO3 product is obtained.

[0043] Step 5: Add saturated sodium sulfate solution to brine 1#, stir and react at room temperature for 3 hours, then filter to obtain solid phase 3# and brine 2#.

[0044] Step 6: Add 1.0 mol / L NaOH solution to brine 2# to adjust the pH to 13, stir at room temperature for 3 hours, and after filtration and washing, obtain solid phase 4# and brine 3#.

[0045] Step 7: Stir solid phase 2# and 10 mL of 40 g / L NaOH solution at 130℃ until completely dissolved. Record the filtrate as solution a and return it to step 1 for recycling as a reaction solution.

[0046] Example 3: A method for extracting lithium from high-calcium lithium-containing brine includes the following steps: Step 1: Add 100 g of sodium aluminate to each liter of water and mix. Stir at 120°C until fully dissolved, then cool to room temperature for later use.

[0047] Step 2: Add 15 mL of sodium aluminate solution from Step 1 to 1000 mL of the original brine, adjust the pH to 5.5, stir at room temperature for 4 h, vacuum filter, wash, and dry the solid phase at 60℃ to constant weight, labeling it as solid phase 1#, and the liquid phase as brine 1# for later use. Analysis showed that Li in brine 1#... + The concentration is 0.5 mg / L, Ca 2+ The concentration was 5444.6 mg / L, Mg 2+ The concentration was 7942.2 mg / L. (For example...) Figure 2As shown, the XRD results of solid phase 1# indicate that LiCl-2Al(OH)3-nH2O (solid phase 1#) is precipitated by the reaction of sodium aluminate with brine under acidic conditions. Solid phase 1# plays a role in selectively fixing lithium ions in the brine.

[0048] Step 3: Mix solid phase 1# with deionized water at a ratio of 1 g: 20 mL, shake for 5 h, dry the filtered solid phase at 60℃ to constant weight, and record it as solid phase 2#. Record the filtrate as filtrate A for later use.

[0049] Step 4: After passing filtrate A through a divalent cation exchange resin (to remove residual calcium and magnesium ions), the solution is concentrated by evaporation at 80°C and normal pressure. A saturated sodium carbonate solution is then added, and after precipitation, Li₂CO₃ is obtained. Figure 3 As shown, the results indicate the formation of Li2CO3 products.

[0050] Step 5: Add saturated sodium sulfate solution to brine 1#, stir and react at room temperature for 3 hours, then filter to obtain solid phase 3# and brine 2#. (Example: ...) Figure 4 As shown, the XRD results of solid phase 3# indicate that calcium ions are separated in the form of calcium sulfate.

[0051] Step 6: Add a 1.0 mol / L NaOH solution to brine #2 to adjust the pH to 13, stir at room temperature for 3 hours, and after filtration and washing, obtain solid phase #4 and brine #3. Figure 5 As shown, the XRD results of solid phase 4# indicate that magnesium ions are separated in the form of magnesium hydroxide.

[0052] Step 7: Stir solid phase 2# and 10 mL of 50 g / L NaOH solution at 120℃ until completely dissolved. The filtrate is recorded as solution a and returned to step 1 for recycling as a reaction solution.

[0053] Comparative Example 1: The specific method is the same as in Example 3, except that the amount of sodium aluminate solution added in step 2 is adjusted to 5 mL, while all other conditions are the same as in step 1. In step 2, brine #1 is used.

[0054] Tests revealed that Li was present in brine #1. + The concentration was 2.2 mg / L, Ca 2+ The concentration was 5028.8 mg / L, Mg 2+ The concentration was 7348.6 mg / L.

[0055] Comparative Example 2: The specific method is the same as in Example 3, except that the pH is adjusted to 7 in step 2, while all other conditions are the same as in step 1. In step 2, brine #1 is used.

[0056] Tests revealed that Li was present in brine #1. + The concentration was 1.1 mg / L, Ca 2+ The concentration was 5028.8 mg / L, Mg 2+ The concentration was 7348.6 mg / L.

[0057] Comparative Example 3: The specific method is the same as in Example 3, except that the pH is controlled to 10 in step 2, while all other conditions are the same as in step 1. In step 2, brine #1 is used.

[0058] Tests revealed that Li was present in brine #1. + The concentration was 6.1 mg / L, Ca 2+ The concentration was 4866.0 mg / L, Mg 2+ The concentration was 6982.8 mg / L.

[0059] It should be noted that the specific embodiments described above are exemplary, and those skilled in the art can devise various solutions inspired by the disclosure of this invention, all of which fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification is illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents.

Claims

1. A method for comprehensive utilization of lithium-containing brine, characterized in that, Includes the following steps: (1) Mix sodium aluminate with water and stir at 100~150℃ until dissolved. After cooling, a sodium aluminate solution is obtained. (2) Add the sodium aluminate solution to the lithium-containing brine, adjust the pH to 4.5~6.5, stir the reaction at room temperature, filter and wash to obtain solid phase 1# and brine 1#, wherein solid phase 1# is aluminum lithium layered hydroxide; (3) Mix the solid phase 1# with water, shake and filter to obtain solid phase 2# and filtrate A; (4) The filtrate A is treated with a divalent cation exchange resin and then evaporated and concentrated. Sodium carbonate solution is added to carry out a precipitation reaction to obtain lithium carbonate. (5) Add sodium sulfate solution to the brine 1#, stir and react, then filter to obtain solid phase 3# and brine 2#; (6) Add sodium hydroxide solution to the brine 2# to adjust the pH to 12~13, stir and react, then filter to obtain solid phase 4# and brine 3#; (7) Mix the solid phase 2# with sodium hydroxide solution and stir at 100~150℃ until dissolved. The resulting solution is returned to step (1) for recycling.

2. The method for comprehensive utilization of lithium-containing brine according to claim 1, characterized in that, In step (1), the mass ratio of sodium aluminate to water is 5~10:

100.

3. The method for comprehensive utilization of lithium-containing brine according to claim 1, characterized in that, In step (2), the volume ratio of the sodium aluminate solution to the lithium-containing primary halogen is 8~15:1000.

4. The method for comprehensive utilization of lithium-containing brine according to claim 1, characterized in that, In step (3), the mass-to-volume ratio of solid phase 1# to water is 1:10~20.

5. The method for comprehensive utilization of lithium-containing brine according to claim 1, characterized in that, In step (4), the divalent cation exchange resin used to remove residual calcium and magnesium ions in filtrate A is any one of D401 resin, D418 resin, Amberlite IRC 748 resin, Purolite S940 resin, and Lewatit TP 208 resin.

6. The method for comprehensive utilization of lithium-containing brine according to claim 1, characterized in that, In steps (4) and (5), the sodium carbonate solution is a saturated sodium carbonate solution.

7. The method for comprehensive utilization of lithium-containing brine according to claim 1, characterized in that, In step (5), the solid phase 3# is calcium sulfate.

8. The method for comprehensive utilization of lithium-containing brine according to claim 1, characterized in that, In step (6), the concentration of the sodium hydroxide solution is 0.5~1.0 mol / L.

9. The method for comprehensive utilization of lithium-containing brine according to claim 1, characterized in that, In step (7), the concentration of the sodium hydroxide solution is 10~50 g / L.

10. A method for selectively separating lithium ions at the front end of lithium-containing brine, characterized in that, Includes the following steps: (1) Mix sodium aluminate with water and stir at 100~150℃ until dissolved. After cooling, a sodium aluminate solution is obtained. (2) Add the sodium aluminate solution to the lithium-containing brine, adjust the pH to 4.5~6.5, stir the reaction at room temperature, filter and wash to obtain a lithium-containing solid phase and delithiated brine, wherein the lithium-containing solid phase is lithium aluminum layered hydroxide; (3) The lithium-containing solid phase is mixed with water, shaken and filtered to obtain lithium-containing filtrate and aluminum hydroxide solid phase.

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