A method for in-situ absorption enrichment of lithium ions in a leaching solution of a clay-type lithium ore

Abstract

This invention discloses a method for in-situ absorption and enrichment of lithium ions in leaching solutions of clay-type lithium ore, relating to the field of lithium extraction technology. The steps are as follows: add 0.1-2.5% CTAB (purity ≥99.0%) and 0.1-5% L-ascorbic acid (purity ≥99.0%) to the lithium ion leaching solution and mix well; adjust the pH to 8.5 by adding 10-30% alkaline substance dropwise while stirring at 200-400 rpm; centrifuge to remove Ca. 2+ Fe 3+ Continue adding alkaline substances to adjust the pH to 13, then centrifuge to remove Mg. 2+ Adjust the pH to 8.5-10.0 using ≥99.9% pure CO2 (below 35℃) to make Li... + With Al 3+ A mixture containing Li5AlO4 was generated; Na was removed by washing with deionized water at 80℃ and filtration. + The precipitate is dried and dried; the precipitate is mixed with water at a ratio of 1:10 to 1:100 and subjected to a hydrothermal reaction at 130-170℃ for 1-7 hours to obtain high-purity Li. + Solution. This invention reduces reagent consumption and equipment corrosion, lowers solid waste costs, improves lithium recovery rate and purity, and is easily industrialized.

Description

Technical Field

[0001] This invention relates to the field of lithium extraction improvement technology, and more specifically, to a method for enriching lithium ions in clay-type lithium ore leaching solution using an aluminum-based in-situ absorbent. Background Technology

[0002] Against the backdrop of the rapid development of the new energy industry, the demand for lithium, as a key resource, is increasing daily. Clay-type lithium deposits, as one of the important sources of lithium resources, have attracted much attention regarding lithium ion extraction technology from their leachate.

[0003] The composition and properties of salt lake brines (an important source of leaching solutions from clay-type lithium deposits) vary significantly depending on geographical location and environmental conditions, and typically contain Mg. 2+ Ca 2+ K + Na + Al 3+ Cl - The diverse ion matrix presents a significant challenge to the extraction of high-purity lithium, necessitating advanced separation technologies to achieve Li… + Effectively distinguishable from other coexisting ions.

[0004] Currently, technologies for extracting lithium from brine encompass a variety of methods, including precipitation, extraction, adsorption, nanofiltration, selective electrodialysis, and electrochemical insertion / deintercalation. Among these, chemical precipitation is a commonly used recovery method in industrial facilities due to its simplicity, cost-effectiveness, and ease of industrial-scale application. This method achieves ion separation from the brine by adding counterions to reduce the solubility of the target ionic component.

[0005] However, traditional chemical precipitation methods have significant drawbacks: 1. Reagent consumption and equipment corrosion issues: This method requires the consumption of a large amount of chemical reagents, and many of these reagents are highly corrosive. Long-term use can easily lead to aging and failure of equipment materials, increasing equipment maintenance and replacement costs. 2. Solid waste disposal and environmental pressure: The reaction process generates a large amount of solid waste, which is costly to dispose of and may pollute the environment, resulting in significant environmental pressure. 3. Low lithium recovery rate: The separation efficiency of nanoscale precipitates (such as magnesium hydroxide) is low, which can easily cause lithium ion entrainment loss during the precipitation-filtration process, resulting in a decrease in lithium yield and increasing the complexity of the process and overall cost.

[0006] To address the aforementioned technical bottlenecks, this invention proposes a method for enriching lithium ions in clay-type lithium ore leaching solutions using an aluminum-based in-situ absorbent. By optimizing process parameters and reaction conditions, this method achieves efficient, low-cost, and environmentally friendly enrichment and extraction of lithium ions. Summary of the Invention

[0007] The core objective of this invention is to provide a method for in-situ absorption and enrichment of lithium ions in clay-type lithium ore leaching solutions, in order to solve the problems of high reagent consumption, severe equipment corrosion, high solid waste disposal costs, and low yield due to lithium ion entrainment loss in traditional chemical precipitation methods, thereby achieving efficient, economical, and environmentally friendly enrichment of lithium ions in clay-type lithium ore leaching solutions.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A method for in-situ absorption and enrichment of lithium ions in leaching solutions of clay-type lithium ore includes the following steps: Step 1: Pretreatment of Leachate Add 0.1-2.5% by mass of CTAB (hexadecyltrimethylammonium bromide) and 0.1-5% by mass of L-ascorbic acid (vitamin C) to the lithium ion leaching solution and mix thoroughly.

[0009] The active ingredient CTAB comprises no less than 99.0% by mass, with a melting point of 248-251℃, a flash point of 244℃, and a density of 1.1107 g / ml (approximate value); the active ingredient L-ascorbic acid comprises no less than 99.0% by mass, with a melting point of 190-194℃ (which is also the decomposition temperature), a flash point of 238.2±23.6℃, ​​and a density of 1.65 g / cm³. 3 Furthermore, its water solubility at 20℃ is 333g / L.

[0010] In addition, depending on the required concentration of the leaching solution, an equal amount of water can be added to the lithium ion leaching solution for dilution before adding the aforementioned CTAB and L-ascorbic acid to optimize subsequent reaction conditions.

[0011] Step 2: Remove Ca 2+ Fe 3+ ion Place the mixture obtained in step one into a stirring device and stir continuously at a speed of 200-400 rpm. Simultaneously, rapidly add 10-30% (w / w) of an alkaline substance to adjust the pH of the solution to 8.5. After the reaction is complete, remove the Ca from the solution by centrifugation. 2+ Fe 3+ The precipitate formed by the ionic reaction yields a product containing Mg. 2+ Li + Al 3+ Na + A mixed solution.

[0012] The alkaline substance is at least one of NH3·H2O, NaOH, and Na2CO3; when NaOH is selected as the alkaline substance, the purity of the NaOH is not less than 97%, and the NaOH can completely dissociate into Na+. + and OH - It can provide a high concentration of OH- in the solution. - Ions, ensuring Ca 2+ Fe 3+ The ionic reaction is thorough and fast, improving the removal of impurities.

[0013] Step 3: Remove Mg 2+ ion While maintaining a stirring speed of 200-400 rpm, continue to rapidly add 10-30% (w / w) of the aforementioned alkaline substance to the mixed solution obtained in step two, adjusting the pH of the solution to 13. After the reaction is complete, centrifuge again to remove the Mg... 2+ The precipitate formed by the ionic reaction yields a product containing only Li. + A 3+ Na + A mixed solution.

[0014] Step 4: In-situ enrichment of lithium ions CO2 gas is bubbled into the mixed solution obtained in step three to adjust the pH of the solution to 8.5-10.0, thereby reducing the concentration of Li in the solution. + With Al 3+ The reaction proceeds completely, producing a mixture containing Li5AlO4, AlO (OH), and Al2O3, thus achieving in-situ absorption and enrichment of lithium ions.

[0015] The purity of the introduced CO2 is not less than 99.9%, and the CO2 introduced and Li + With Al 3+ The reaction absorption process needs to be carried out below 35°C to ensure the stability of the reaction and the enrichment efficiency of lithium ions.

[0016] Step 5: Remove Na + Ionize and dry the precipitate The mixture obtained in step four was washed and filtered multiple times with deionized water at 80°C to separate and remove most of the Na from the precipitate. + Ions; after washing, the precipitate is dried in an oven at 80℃ for later use.

[0017] Step Six: Hydrothermal Reaction to Prepare High-Purity Li + solution The precipitate dried in step five was mixed with water at a mass ratio of 1:10 to 1:100 and placed in a homogeneous reactor. The mixture was then subjected to a hydrothermal reaction at 130℃-170℃ for 1-7 hours. After the reaction was completed, high-purity Li was obtained. + Solution.

[0018] In a preferred embodiment of the present invention, the hydrothermal reaction in step six can be performed using the following parameters: Parameter 1: The mass ratio of precipitate to water is 1:10, the hydrothermal reaction temperature is 150℃, and the reaction time is 7h. Under these conditions, the lithium ion leaching rate is optimal. Parameter 2: The mass ratio of precipitate to water is 1:50, the hydrothermal reaction temperature is 130℃, and the reaction time is 4-5 hours. Under these parameters, production efficiency can be improved while ensuring lithium purity.

[0019] The beneficial effects of this invention are as follows: 1. Compared with traditional chemical precipitation methods, this invention significantly reduces reagent consumption by precisely controlling the amount and purity of CTAB, L-ascorbic acid, alkaline substances and CO2; at the same time, by optimizing reaction conditions, it reduces the damage of highly corrosive environments to equipment, extends equipment lifespan, and reduces maintenance costs. 2. The reaction process of the present invention is more selective, removing only impurity ions, reducing the amount of solid waste generated, and lowering the cost of solid waste disposal and environmental pressure; 3. By employing stepwise impurity removal, in-situ enrichment, and hydrothermal reaction optimization, lithium ion entrainment loss during the precipitation-filtration process is effectively avoided, thereby improving lithium recovery rate; the final prepared Li + The solution has high purity and can be directly used for subsequent lithium product processing; 4. The process parameters of this invention are clear and controllable, the reaction conditions are mild, and each step is simple to operate, making it easy to achieve industrial-scale production and possessing high industrial application value. Attached Figure Description

[0020] 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.

[0021] Figure 1: A schematic diagram of the lithium-ion in-situ aluminum-based adsorbent and desorption process of the present invention; Figure 2: XRD pattern of lithium ion precipitate adsorbed by aluminum-based adsorbent; Figure 3: XRD pattern of the aluminum-based adsorbent after desorption of lithium ions; Figure 4: A graph showing the relationship between solution pH change and reaction progress during the CO2 introduction stage in the process of enriching lithium ions with aluminum-based adsorbents. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] A method for in-situ absorption and enrichment of lithium ions in leaching solutions of clay-type lithium ore is provided, comprising the following steps: Step 1: Take 2L of lithium-containing leaching solution with a concentration of 180ppm, and add 2.5% CTAB (99.2% of the effective ingredient by mass) and 0.1% L-ascorbic acid (99.1% of the effective ingredient by mass) to it in sequence, and mix well; Step 2: Stir the solution obtained in Step 1 at 300 rpm while rapidly adding 30% NaOH (97.5% purity) dropwise to adjust the pH to 8.5. Centrifuge to remove Ca. 2+ Fe 3+ Precipitate, yielding Mg 2+ Li + Al 3+ Na + The solution; Step 3: While maintaining a stirring speed of 300 rpm, continue to rapidly add 30% NaOH (97.5% purity) dropwise to the solution obtained in Step 2, adjust the pH to 13, centrifuge to remove Mg. 2+ The precipitate yielded Li-containing material. + Al 3+ Na + The solution; Step 4: At 28℃, introduce 5L of 99.92% pure CO2 gas into the solution obtained in Step 3 to adjust the pH of the solution to 9.2, so that Li + With Al 3+ The reaction completely produces a mixture of Li5AlO4, AlO (OH), and Al2O3. Step 5: Wash and filter the above mixture with deionized water at 80℃ to separate and remove Na. + The precipitate was dried in an 80℃ oven. Step Six: Mix the dried precipitate with water at a mass ratio of 1:15, place the mixture in a homogeneous reactor, and perform a hydrothermal reaction at 150℃ for 7 hours to finally obtain 200 ml of Li-containing solution. + A high-purity solution of 1760 ppm.

[0025] Example 2

[0026] A method for in-situ absorption and enrichment of lithium ions in leaching solutions of clay-type lithium ore includes the following steps: Step 1: Take 2L of lithium-containing leaching solution with a concentration of 180ppm, first add 2L of water to dilute it, then add 2.0% CTAB (99.0% of the effective ingredient by mass) and 0.1% L-ascorbic acid (99.3% of the effective ingredient by mass) by mass in sequence, and mix well; Step 2: Stir the solution obtained in Step 1 at 300 rpm while rapidly adding 10% NaOH (97.1% purity) dropwise to adjust the pH to 8.5. Centrifuge to remove Ca. 2+ Fe 3+ Precipitate, yielding Mg 2+ Li + Al 3+ Na + The solution; Step 3: While maintaining a stirring speed of 300 rpm, continue to rapidly add 10% NaOH (97.1% purity) dropwise to the solution obtained in Step 2, adjust the pH to 13, centrifuge to remove Mg. 2+ The precipitate yielded Li-containing material. + Al 3+ Na + The solution; Step 4: At 32℃, introduce 5L of 99.9% pure CO2 gas into the solution obtained in Step 3 to adjust the pH of the solution to 8.8. + With Al 3+ The reaction completely produces a mixture of Li5AlO4, AlO (OH), and Al2O3. Step 5: Wash and filter the above mixture with deionized water at 80℃ to separate and remove Na. + The precipitate was dried in an 80℃ oven. Step Six: Mix the dried precipitate with water at a mass ratio of 1:50, place the mixture in a homogeneous reactor, and perform a hydrothermal reaction at 130℃ for 4 hours to finally obtain 300 ml of Li-containing solution. + A high-purity solution of 1160 ppm.

[0027] Example 3

[0028] A method for in-situ absorption and enrichment of lithium ions in leaching solutions of clay-type lithium ore includes the following steps: Step 1: Take 2L of lithium-containing leaching solution with a concentration of 180ppm, and add 1.5% CTAB (99.4% of the effective ingredient by mass) and 0.05% L-ascorbic acid (99.2% of the effective ingredient by mass) to it in sequence, and mix well; Step 2: Stir the solution obtained in Step 1 at 300 rpm while rapidly adding 15% NaOH (97.3% purity) dropwise to adjust the pH to 8.5. Centrifuge to remove Ca. 2+ Fe 3+ Precipitate, yielding Mg 2+ Li + Al 3+ Na + The solution; Step 3: While maintaining a stirring speed of 300 rpm, continue to rapidly add 15% NaOH (97.3% purity) dropwise to the solution obtained in Step 2, adjust the pH to 13, centrifuge to remove Mg. 2+ The precipitate yielded Li-containing material. + Al 3+ Na + The solution; Step 4: At 30℃, introduce 8L of 99.95% pure CO2 gas into the solution obtained in Step 3 to adjust the pH of the solution to 9.5, so that Li + With Al 3+ The reaction completely produces a mixture of Li5AlO4, AlO(OH), and Al2O3. Step 5: Wash and filter the above mixture with deionized water at 80℃ to separate and remove Na. + The precipitate was dried in an 80℃ oven. Step Six: Mix the dried precipitate with water at a mass ratio of 1:60, place the mixture in a homogeneous reactor, and perform a hydrothermal reaction at 160℃ for 1 hour to finally obtain 350 ml of Li-containing solution. + A high-purity solution of 1008 ppm.

[0029] The above embodiments demonstrate that the method of the present invention can effectively enrich lithium ions in clay-type lithium ore leaching solutions, and has the characteristics of low reagent consumption, good environmental performance, high lithium recovery rate, and excellent product purity, which can meet the needs of industrial production.

[0030] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for enriching lithium ions in clay-type lithium ore leaching solution using an aluminum-based in-situ absorbent, characterized in that, Includes the following steps: Step 1: Add 0.1-2.5% CTAB and 0.1-5% L-ascorbic acid by mass to the lithium ion leaching solution in sequence, and mix well; Step 2: While stirring the solution obtained in Step 1 at a speed of 200-400 rpm, rapidly add an alkaline substance with a mass fraction of 10-30% to adjust the pH of the solution to 8.

5. Centrifuge to remove Ca. 2+ Fe 3+ The precipitate formed by the ions yields a product containing Mg. 2+ Li + Al 3+ Na + A mixed solution; the alkaline substance is at least one of NH3·H2O, NaOH, and Na2CO3; Step 3: While stirring the mixture obtained in Step 2 at a speed of 200-400 rpm, continue to rapidly add the alkaline substance with a mass fraction of 10-30% to adjust the pH of the solution to 13. Centrifuge to remove Mg. 2+ The precipitate formed yields Li-containing products. + Al 3+ Na + A mixed solution; Step 4: Pass CO2 gas into the mixed solution obtained in Step 3 to adjust the pH of the solution to 8.5-10.0, so that Li + With Al 3+ The reaction proceeds completely, producing a mixture containing Li5AlO4, AlO(OH), and Al2O3, thus achieving the absorption and enrichment of lithium ions. Step 5: Wash and filter the mixture obtained in Step 4 with deionized water at 80℃ to separate and remove Na from the precipitate. + The precipitate was then dried in an 80°C oven. Step Six: Mix the dried precipitate from Step Five with water at a mass ratio of 1:10 to 1:100, and perform a hydrothermal reaction in a homogeneous reactor at 130℃-170℃ for 1-7 hours to obtain high-purity Li. + Solution.

2. The method for in-situ absorption and enrichment of lithium ions in clay-type lithium ore leaching solution according to claim 1, characterized in that, In step one, the CTAB active ingredient comprises no less than 99.0% by mass, and the CTAB has a melting point of 248-251℃, a flash point of 244℃, and a density of 1.1107 g / ml; the L-ascorbic acid active ingredient comprises no less than 99.0% by mass, and the L-ascorbic acid has a melting point of 190-194℃, a flash point of 238.2±23.6℃, ​​and a density of 1.65 g / cm³. 3 Furthermore, its water solubility at 20℃ is 333g / L.

3. The method for in-situ absorption and enrichment of lithium ions in clay-type lithium ore leaching solution according to claim 1, characterized in that, When using the alkaline substance NaOH in steps two and three, its purity must be no less than 97%.

4. The method for in-situ absorption and enrichment of lithium ions in clay-type lithium ore leaching solution according to claim 1, characterized in that, The purity of CO2 mentioned in step four is not less than 99.9%, and the introduction of CO2 causes Li... + With Al 3+ The absorption process of the reaction takes place below 35°C.

5. The method for in-situ absorption and enrichment of lithium ions in clay-type lithium ore leaching solution according to claim 1, characterized in that, The alkaline substance mentioned in step two is NaOH; the NaOH can completely dissociate into Na + and OH - Provides high concentrations of OH - ion.

6. The method for in-situ absorption and enrichment of lithium ions in clay-type lithium ore leaching solution according to claim 1, characterized in that, The lithium ion leaching solution described in step one can be diluted with an equal amount of water before adding CTAB and L-ascorbic acid.

7. The method for in-situ absorption and enrichment of lithium ions in clay-type lithium ore leaching solution according to claim 1, characterized in that, In step six, the mass ratio of precipitate to water is 1:10, the hydrothermal reaction temperature is 150℃, and the hydrothermal reaction time is 7h.

8. The method for in-situ absorption and enrichment of lithium ions in clay-type lithium ore leaching solution according to claim 1, characterized in that, In step six, the mass ratio of precipitate to water is 1:50, the hydrothermal reaction temperature is 130℃, and the hydrothermal reaction time is 4-5 hours.

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