An adsorbent precursor for lithium ion recovery, a preparation method thereof, and an adsorbent

Abstract

The present application discloses an adsorbent precursor for lithium ion recovery, a preparation method thereof, and an adsorbent. The preparation method of the adsorbent precursor includes the following steps: S1: Mix a titanium source and a lithium source in a dispersion medium to obtain a raw material slurry; S2: Spray-dry the raw material slurry and crush the dried powder to obtain a raw material powder; S3: Place the raw material powder in a chemical vapor deposition furnace, introduce a gaseous carbon source at high temperature for reaction and carbon film deposition to obtain an adsorbent precursor for lithium ion recovery. The adsorbent precursor for lithium ion recovery of the present application utilizes chemical vapor deposition to modify a dense carbon film in the adsorbent, which is beneficial to improving the service life and stability of the adsorbent.

Description

Technical Field

[0001] This application relates to the technical field of lithium extraction from salt lakes, and specifically relates to an adsorbent precursor for lithium ion recovery, a preparation method thereof, and an adsorbent. Background Art

[0002] China has a huge reserve of lithium resources, and there are rich lithium resources in salt lakes in Qinghai and Tibet. In the technology of lithium extraction from salt lakes, lithium adsorbents play a crucial role. Lithium adsorbents can effectively selectively adsorb lithium ions from brine and achieve separation from other metal ions such as magnesium ions. Currently, the lithium adsorbents used in China are mainly divided into organic adsorbents and inorganic adsorbents. Inorganic adsorbents can be further subdivided into types such as ion sieve adsorbents, titanium-based adsorbents, and natural mineral adsorbents.

[0003] As a new type of adsorbent for lithium extraction from salt lakes, the main application system of titanium-based adsorbents is the hydrochloric acid desorption system. The core skeleton of titanium-based adsorbents is prone to dissolution damage, rupture, or collapse during desorption in solution, seriously affecting the recycling of the adsorbent. Therefore, it is necessary to design a titanium-based adsorbent with a long service life. Summary of the Invention

[0004] The purpose of this application is to provide a titanium-based adsorbent with a long service life.

[0005] To achieve the above object, the technical solution adopted in this application is as follows: providing a preparation method for an adsorbent precursor for lithium ion recovery, including the following steps: S1: Mix a titanium source and a lithium source in a dispersion medium to obtain a raw material slurry; S2: Spray-dry the raw material slurry and crush the dried powder to obtain a raw material powder; S3: Place the raw material powder in a chemical vapor deposition furnace, and introduce a gaseous carbon source at high temperature for reaction and carbon film deposition to obtain the adsorbent precursor for lithium ion recovery.

[0006] As a preference, the lithium source and the titanium source are mixed according to a molar ratio of lithium to titanium of 0.8 to 2.0.

[0007] As another preference, the lithium source and the titanium source are mixed according to a molar ratio of lithium to titanium of 2.

[0008] As another preference, the gaseous carbon source is one of methane, ethylene, acetylene, vaporized ethanol, vaporized acetone, and vaporized toluene.

[0009] As another preference, the gaseous carbon source is acetylene.

[0010] As another preference, the reaction temperature in step S3 is 500 to 900 °C, and the reaction time is 3 to 10 h.

[0011] As another preference, an inert gas is further introduced into the chemical vapor deposition furnace in the step S3.

[0012] More preferably, in the step S1, through wet grinding, the titanium source and the lithium source are uniformly mixed in the dispersion medium.

[0013] Provided is an adsorbent precursor for lithium ion recovery, which is prepared by any of the above-mentioned preparation methods.

[0014] An adsorbent for lithium ion recovery is obtained by activating the above-mentioned adsorbent precursor for lithium ion recovery with an acid solution.

[0015] Compared with the prior art, the beneficial effects of the present application are as follows:

[0016] (1) For the adsorbent precursor for lithium ion recovery of the present application, a dense carbon film is modified on the adsorbent by chemical vapor deposition, which is beneficial to improving the service life and stability of the adsorbent;

[0017] (2) For the adsorbent precursor for lithium ion recovery of the present application, the preparation method is simple, the raw materials are easy to obtain, it is suitable for large-scale production, and the adsorbent is applicable to lithium extraction and lithium recovery fields such as salt lake brine, lithium precipitation mother liquor, and lithium-containing waste liquid, with wide applications. Specific Embodiments

[0018] Next, in combination with specific embodiments, the present application will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be combined arbitrarily to form new embodiments.

[0019] The terms "comprising" and "having" in the description and claims of the present application and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0020] The present application provides an adsorbent precursor for lithium ion recovery, which is prepared by using the following steps:

[0021] S1: Mix the titanium source and the lithium source in a dispersion medium to obtain a raw material slurry;

[0022] S2: Spray-dry the raw material slurry and crush the dried powder to obtain a raw material powder;

[0023] S3: Place the raw material powder in a chemical vapor deposition furnace, introduce a gaseous carbon source at high temperature for synthesis and carbon film deposition, to obtain the adsorbent precursor for lithium ion recovery of the present application.

[0024] In some embodiments, the lithium source and the titanium source are mixed according to a molar ratio of lithium to titanium of 0.8 to 2.0.

[0025] In a more preferred embodiment, the lithium source and the titanium source are mixed according to a molar ratio of lithium to titanium of 2, which can enable the adsorbent to have a better adsorption capacity.

[0026] The lithium source can be lithium carbonate, lithium hydroxide or a mixture of the two; the titanium source is titanium dioxide.

[0027] In some embodiments, the dispersion medium includes a dispersion solution and a dispersant, which are used to better uniformly mix the titanium source and the lithium source. The dispersion solution can be water, ethanol, isopropanol, etc., and the dispersant can be polyethylene glycol, polypropylene pyrrolidone, glucose, etc.

[0028] In step S3, the synthesis reaction of lithium metatitanate is carried out on the titanium source and the lithium source in the high-temperature environment of the chemical vapor deposition furnace. At the same time, a gaseous carbon source is introduced into the chemical vapor deposition furnace to deposit a dense carbon film on the synthesized lithium metatitanate.

[0029] In the adsorbent precursor for lithium ion recovery of the present application, by depositing a dense carbon film on the adsorbent during the preparation process, the chemical interfacial reaction of Ti can be reduced, its adsorption capacity for lithium ions can be improved, and it has better stability and a longer service life, and can be applied in more systems.

[0030] In some embodiments, the gaseous carbon source can be methane, ethylene, acetylene, vaporized ethanol, vaporized acetone, vaporized toluene, etc., and the purity of the gaseous carbon source needs to be above 98%.

[0031] In a more preferred embodiment, the gaseous carbon source is acetylene, which can enable the adsorbent to have a better adsorption capacity.

[0032] In some embodiments, in step S3, the chemical vapor deposition furnace is set at 500 - 900 °C, and the reaction time is 3 - 10 h.

[0033] In some embodiments, an inert gas is introduced into the chemical vapor deposition furnace, which is used to discharge the air in the furnace, serve as a carrier for the gaseous carbon source, and control the pressure in the furnace, etc.

[0034] In some embodiments, in step S1, the lithium source and the titanium source are mixed into a raw material slurry by grinding.

[0035] The raw materials of the preparation method of the present application are widely sourced, easy to obtain, low in price, and the process production process is simple and easy to mass-produce on a large scale.

[0036] The present application provides an adsorbent precursor for lithium ion recovery, which is prepared by the above method and has the advantages of strong stability, long service life, good economic practicability, etc.

[0037] The present application also provides an adsorbent, which is obtained by activating the above adsorbent precursor with an acid solution. The adsorbent of the present application can be used in lithium extraction from salt lakes, lithium extraction from mother liquor of lithium precipitation, or lithium recovery from lithium-containing waste liquid, and has wide application, stable properties and long service life.

[0038] Disperse the adsorbent precursor prepared by the above preparation method in a dilute acid solution with a pH value less than or equal to 2, stir and activate for a period of time, separate and dry the powder to obtain an adsorbent for lithium ion recovery.

[0039] Example 1

[0040] An adsorbent precursor for lithium ion recovery, according to the following preparation steps:

[0041] S1: Dissolve 554.4 g of lithium carbonate, 600.0 g of titanium dioxide and 30.0 g of polyvinylpyrrolidone in 4 L of ultrapure water, transfer to a ball mill for wet grinding and mixing. The grinding material is zirconia balls with a diameter of 0.1 - 1 mm, the rotation speed is 800 rpm, and the grinding and mixing time is 3 h to obtain a raw material slurry;

[0042] S2: Spray-dry the raw material slurry, set the inlet temperature to 220 ± 40 °C and the outlet temperature to 100 ± 10 °C, and then perform jet milling on the dried powder to obtain a raw material powder;

[0043] S3: Place the raw material powder in a chemical vapor deposition furnace, introduce nitrogen and use acetylene as the gaseous carbon source, and react at 700 °C for 8 h to obtain the adsorbent precursor for lithium ion recovery of the present application.

[0044] Activate the adsorbent precursor: Weigh 20 g of the adsorbent precursor, add 1 L of 0.05 mol / L dilute sulfuric acid solution, stir, control the pH value = 1.00, separate and dry after activation for 4 h to obtain an adsorbent for lithium ion recovery.

[0045] Example 2

[0046] Adjust the addition amount of lithium carbonate in step S1 to 416.4 g, and keep other preparation steps the same as in Example 1.

[0047] Example 3

[0048] Adjust the addition amount of lithium carbonate in step S1 to 346.5 g, and keep other preparation steps the same as in Example 1.

[0049] Example 4

[0050] An adsorbent precursor for lithium ion recovery is prepared according to the following steps:

[0051] S1: Dissolve 221.7 g of lithium carbonate, 600.0 g of titanium dioxide and 35.0 g of polyvinylpyrrolidone in 2.5 L of ultrapure water, transfer it to a ball mill for wet grinding and mixing. The grinding medium is zirconia balls with a diameter of 0.1 - 1 mm, the rotation speed is 800 rpm, and the grinding and mixing time is 2 h to obtain a raw material slurry.

[0052] S2: Spray dry the raw material slurry, set the inlet temperature to 220 ± 40 °C and the outlet temperature to 100 ± 10 °C. Then, air-grind the dried powder to obtain a raw material powder.

[0053] S3: Place the raw material powder in a chemical vapor deposition furnace, introduce argon and use vaporized ethanol as a gaseous carbon source, and react at 700 °C for 8 h to obtain the adsorbent precursor for lithium ion recovery in this application.

[0054] The activation of the adsorbent precursor is the same as the steps in Example 1.

[0055] Example 5

[0056] Adjust the reaction time in step S3 to 6.5 h, and keep the other preparation steps the same as in Example 4.

[0057] Example 6

[0058] Adjust the reaction temperature in step S3 to 900 °C and the reaction time to 8 h, and keep the other preparation steps the same as in Example 1.

[0059] Comparative Example 1

[0060] Synthesize lithium metatitanate using lithium carbonate and titanium dioxide. Place the lithium metatitanate in a chemical vapor deposition furnace, introduce nitrogen and use acetylene as a gaseous carbon source, and react at 700 °C for 8 h to obtain an adsorbent precursor in a post-deposition form.

[0061] The activation of the adsorbent precursor is the same as the steps in Example 1.

[0062] Performance Test

[0063] Prepare simulated brine according to the concentrations of each ion in Table 1 below. Weigh 20 g of the lithium ion adsorbent materials prepared in Examples 1 - 6 and Comparative Example 1, add them to 2 L of brine for adsorption, and the adsorption time is 2 h. Test the lithium content in the tail liquid after adsorption by the adsorbent.

[0064] Table 1 Contents of Each Ion in Simulated Brine

[0065] Element <![CDATA[Na + > <![CDATA[K + > <![CDATA[Li + > <![CDATA[Mg 2+ > <![CDATA[Ca 2+ > B Content (mg / L) 16501.5 2513.0 312.2 523.0 48.3 230.2

[0066] The adsorbent is desorbed. Sulfuric acid with a concentration of 0.1 mol / L is used. The adsorbent after adsorbing lithium ions is dispersed in 1 L of sulfuric acid, and the desorption time is 4 h. After desorption is completed, the adsorbent and sulfuric acid are separated to obtain a desorption solution, and the contents of lithium and titanium in the desorption solution are tested.

[0067] The above adsorption-desorption process is repeated 5 times for the adsorbents of each example and comparative example, and the attenuation of the adsorbent capacity is observed.

[0068] The relevant calculation formulas involved are as follows:

[0069] Adsorption capacity = (c 卤水Li -c 尾液Li ) × V 卤水 / m 吸附剂

[0070] Desorption capacity = c 解吸液Li × V 解吸液 / m 吸附剂

[0071] Dissolution loss rate = c 解吸液Ti × V 解吸液 / (m 吸附剂 × 0.522) × 100%

[0072] c 卤水Li ----Li concentration in brine, g / L

[0073] c 尾液Li ----Li concentration in adsorption tail liquid, g / L

[0074] V 卤水 ----Brine volume, L

[0075] m 吸附剂 ----Adsorbent mass, g

[0076] c 解吸液Li ----Li concentration in desorption solution, g / L

[0077] V 解吸液 ----Desorption solution volume, L

[0078] c 解吸液Ti ----Ti concentration in desorption solution, g / L

[0079] The adsorption test results and the calculated results of the average dissolution loss rate of each example and comparative example 1 are recorded in Table 2 below.

[0080] Table 2 Performance test results of Examples 1 to 6 and Comparative Example 1

[0081]

[0082] Analyzing the performance test results of Examples 1 to 6 and Comparative Example 1, for an adsorbent for lithium ion recovery in the present application, after surface modification with a dense carbon layer, the dissolution loss rate of the adsorbent is significantly reduced, and the capacity attenuation of the adsorbent in a sulfuric acid environment is slow, indicating that the dense carbon film on the adsorbent surface enhances the sulfuric acid tolerance of the adsorbent and reduces the titanium dissolution loss of the adsorbent during the desorption process.

[0083] Analyzing the performance test results of Examples 1 to 3, the lithium-titanium ratio in the synthesis raw materials affects both the adsorption capacity and the dissolution loss rate of the adsorbent. When the lithium-titanium ratio is 2 in Example 1, a better adsorption capacity of the adsorbent can be obtained.

[0084] Analyzing the performance test results of Examples 4 and 5, by extending the reaction time in Step S3, the dissolution loss rate of the adsorbent is slightly reduced, and the stability of the adsorbent in a sulfuric acid system is slightly enhanced.

[0085] Analyzing the performance test results of Examples 1 and 6, by increasing the reaction temperature in Step S3, the dissolution loss rate of the adsorbent is slightly reduced, and at the same time the adsorption capacity decreases.

[0086] The adsorbent for lithium ion recovery prepared in the present application can still maintain a good adsorption capacity after 5 rounds of cyclic use in a sulfuric acid system, has less dissolution loss, significantly enhanced stability, and significantly improved service life.

[0087] The basic principles, main features and advantages of the present application have been described above. Those skilled in the art of this industry should understand that the present application is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present application. Without departing from the spirit and scope of the present application, the present application will have various changes and improvements, and these changes and improvements all fall within the scope of the present application claimed. The scope of protection required by the present application is defined by the appended claims and their equivalents.

Claims

1. An adsorbent for lithium ion recovery, characterized in that: preparing an adsorbent precursor, and then activating the adsorbent precursor with an acid solution to obtain the adsorbent, Wherein, the adsorbent precursor is prepared by the following steps: S1: mixing a titanium source and a lithium source in a dispersion medium to obtain a raw material slurry; S2: spray drying the raw material slurry and crushing the dried powder to obtain raw material powder; S3: The raw material powder is placed in a chemical vapor deposition furnace, and a gaseous carbon source is introduced at high temperature to carry out reaction and carbon film deposition, so as to obtain the adsorbent precursor for lithium ion recovery.

2. The adsorbent according to claim 1, characterized in that The lithium source and the titanium source are mixed in a molar ratio of lithium to titanium of 0.8 to 2.

0.

3. The adsorbent according to claim 2, characterized in that The lithium source and the titanium source are mixed in a molar ratio of lithium to titanium of 2.

4. The adsorbent according to claim 1, characterized in that The gaseous carbon source is one of methane, ethylene, acetylene, vaporized ethanol, vaporized acetone, and vaporized toluene.

5. The adsorbent according to claim 4, characterized in that The gaseous carbon source is acetylene.

6. The adsorbent according to claim 1, characterized in that The reaction temperature in step S3 is 500-900° C., and the reaction time is 3-10 hours.

7. The adsorbent according to claim 4, characterized in that In the step S3, an inert gas is also introduced into the vapor deposition furnace.

8. The adsorbent according to claim 1, characterized in that In the step S1, the titanium source and the lithium source are uniformly mixed in the dispersion medium by wet grinding.

Images