Lithium zirconate titanate lithium ion sieve as well as preparation method and application thereof

Abstract

The invention discloses a lithium zirconate titanate lithium ion sieve as well as a preparation method and application thereof, and the preparation method of the lithium zirconate titanate lithium ion sieve comprises the following steps: a, preparing metatitanic acid slurry; b, filtering the metatitanic acid slurry in the step a, washing with water to obtain a filter cake, and adding a lithium salt solution into the filter cake to prepare slurry C; c, adding zirconium carbonate and lithium carbonate into the slurry C obtained in the step b, and uniformly stirring to obtain slurry D; d, adding isopropanol, acrylamide and aluminum sol into the slurry D, and uniformly stirring to obtain slurry E; and e, adding an initiator into a mixed solution of polymethylsilicone oil and polyether silicone oil, heating, dropwise adding the slurry E into the mixed solution in the form of liquid drops to obtain precursor rubber balls of the ion sieve, cleaning, drying, calcining and activating to obtain the ion sieve. The prepared lithium zirconate titanate lithium ion sieve is high in lithium ion adsorption capacity, high in selectivity and long in service life.

Description

Technical Field

[0001] The present invention relates to the field of ion sieves, and in particular to a lithium zirconate titanate ion sieve and a preparation method and application thereof. The lithium zirconate titanate ion sieve has high selectivity and high capacity. Background Art

[0002] With the continuous deepening of scientific research and the continuous innovation of science and technology, the prospects of lithium in the civilian field are becoming more and more broad. Globally, China is one of the countries with the fastest growth in lithium consumption and the largest demand. With the continuous maturity and development of lithium battery technology, a new and huge market has been opened up for lithium.

[0003] At present, the global lithium resources are mainly salt lake brine lithium resources, whose reserves account for 72.31% of the global total, and ore lithium resources account for 20.26% of the global lithium resource reserves. 70% of the raw materials for lithium carbonate produced globally come from salt lake brine, and only 30% come from ores. However, the proportion of lithium extraction from brine in my country is relatively low, and the proportion of lithium extraction from ores is as high as 80%.

[0004] The salt lake brine extraction technologies currently used in the world mainly include precipitation method, calcination leaching method, solvent extraction method, adsorption method, electrodialysis method, etc.

[0005] The Chinese patent application with publication number CN117983178A discloses a method for preparing a self-excited perovskite-based composite lithium ion sieve, wherein the A-site material, the B-site material and the lithium salt template are mixed evenly, sintered in one step and subjected to a delithiation step to prepare a self-excited perovskite-based composite lithium ion sieve with high selective adsorption of lithium ions, wherein the A-site material is a carbonate of strontium, barium, bismuth, iron, cobalt, nickel, etc., the B-site material includes a carbonate of manganese, iron, cobalt, nickel, zirconium, niobium, antimony, tantalum, tin, titanium, etc., and the lithium salt template includes one or a mixture of two or more of lithium sulfate, lithium carbonate, lithium bicarbonate, lithium chloride, lithium nitrate, lithium silicate, lithium phosphate, lithium acetate, lithium oxalate or lithium hydroxide. The ion sieve prepared by this scheme is in powder form, and there are the following difficulties in subsequent industrial production:

[0006] 1. During the acid leaching analysis process, the ion sieve has a high dissolution loss.

[0007] 2. After being filled into the loading tower, there is basically no space between the powders, the salt lake brine cannot flow and cannot be used for industrial production.

[0008] 3. When the reactor is used for stirring and extracting lithium, solid-liquid separation is required, and some nano-scale powders cannot be recovered during the separation.

[0009] The Chinese patent with publication number CN112871126B discloses a method for preparing lithium ion sieve particles with high adsorption capacity, wherein the lithium ion sieve powder is slurried with deionized water, a dispersant is added and then sanded with a sand mill, an inorganic binder is added to the slurry after sanding, and micron-sized lithium ion sieve particles are obtained after spray drying; the inorganic binder includes silica sol, aluminum sol, sodium silicate, potassium silicate, and aluminum phosphate, and the amount of inorganic binder added is 1%-10% of the mass of the micron-sized lithium ion sieve particles. This scheme uses ion sieve powder and then processes it into plastic particles for industrial use through secondary processing, and the process flow is relatively complicated. Summary of the invention

[0010] The purpose of the present invention is to provide a lithium zirconate titanate lithium ion sieve and a preparation method thereof, which has high lithium ion adsorption capacity, high selectivity and long service life.

[0011] The present invention also provides the use of the lithium zirconate titanate lithium ion sieve in separating lithium from salt lake brine, which has high lithium ion adsorption capacity and high selectivity.

[0012] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0013] A method for preparing a lithium zirconate titanate lithium ion sieve comprises the following steps:

[0014] Step a. preparing titanate slurry;

[0015] Step b. filtering the titanate slurry in step a, washing with water to obtain a filter cake, and adding a lithium salt solution to the filter cake to prepare a slurry C;

[0016] Step c. Add zirconium carbonate and lithium salt to the slurry C obtained in step b, stir evenly to obtain slurry D;

[0017] Step d. Add isopropanol, acrylamide and aluminum sol to slurry D and stir evenly to obtain slurry E;

[0018] Step e. adding an initiator to a mixed solution of polymethyl silicone oil and polyether silicone oil and heating the mixture, and then dripping slurry E into the mixture in the form of droplets to obtain ion sieve precursor colloid balls;

[0019] Step f. Washing the precursor colloid ball in step e with an ethanol aqueous solution;

[0020] Step g. Drying the cleaned precursor rubber balls;

[0021] Step h. placing the dried precursor rubber balls into a rotary kiln for calcination;

[0022] Step i. Step h: adding a dilute acid solution to activate the microbeads obtained after calcination.

[0023] The present invention does not need to prepare ion sieve powder in advance. The present invention uses titanic acid to form ion sieve microbeads through one-time molding, and does not need secondary processing. The prepared ion sieve has high lithium ion adsorption capacity and high selectivity.

[0024] In a preferred embodiment of the present invention, in step e, the mass ratio of polymethyl silicone oil to polyether silicone oil in the mixed solution of polymethyl silicone oil and polyether silicone oil is 50-70wt%:20-50wt%; preferably, the mass ratio of polymethyl silicone oil to polyether silicone oil in the mixed solution of polymethyl silicone oil and polyether silicone oil is 60-70wt%:20-40wt%.

[0025] The mixed solution of methyl silicone oil and polyether silicone oil in this mass ratio range can ensure that when the subsequent droplets enter the organic phase from the aqueous phase, the droplets are formed to maintain a granular shape and will not fall apart, while taking the cost into consideration.

[0026] In a preferred embodiment of the present invention, in step e, the heating temperature is 70-90° C. This temperature range is conducive to droplet formation, and the droplets are not easy to form at a temperature below 70° C.

[0027] In a preferred embodiment of the present invention, in step e, the diameter of the droplets of slurry E is 4 mm to 5 mm.

[0028] Select a needle with a suitable aperture and control the diameter of the dripping droplets to be 4mm to 5mm. If the droplet diameter is less than 4mm, the diameter of the formed ion sieve will be too small, which will not be conducive to water flow after loading into the loading tower. If the droplet diameter is too large, it will affect the adsorption capacity and selectivity. The droplets within the diameter range of the present application are beneficial to improving the adsorption capacity and selectivity of lithium zirconate titanate lithium ion sieve.

[0029] In a preferred embodiment of the present invention, in step h, calcination is carried out in two steps, first calcination at 400-600° C. for 1-2 h, and then calcination at 800-900° C. for 2-3 h.

[0030] Calcination at 400-600℃ for 1-2h is for debinding. Using a rotary kiln for calcination can maintain continuous production and prevent the micro-beads from sintering. Calcination in two temperature ranges, especially calcination in the low temperature range for 1-2h, can ensure that the final product is a regular spherical shape. Otherwise, the calcined product will have an irregular shape, which is beneficial to improving the application performance of lithium zirconate titanate lithium ion sieve.

[0031] In a preferred embodiment of the present invention, in order to dry the water and ethanol therein, in step g, the drying temperature is 120-140° C. and the drying time is not less than 2 hours.

[0032] In a preferred embodiment of the present invention, in step e, the initiator is a mixture of one or more of benzoyl, phenylacetyl and styrene; preferably, the mass percentage of the initiator is 5 to 15 wt%.

[0033] The initiator is added to make the droplets easier to form and the surface of the formed rubber balls smoother.

[0034] The lithium salt solution in step b and step c is one or more of lithium sulfate, lithium carbonate, lithium bicarbonate, lithium chloride, lithium nitrate, lithium silicate, lithium phosphate, lithium acetate, lithium oxalate or lithium hydroxide. The lithium salt solution in step b is preferably a saturated lithium carbonate solution, and the lithium salt solution in step c is preferably lithium carbonate powder. The carbonate radical is converted into CO in the subsequent calcination process. 2 Volatile, no residue.

[0035] In a preferred embodiment of the present invention, in step c, the added lithium salt is lithium carbonate, and the TiO 2 The mass ratio of lithium carbonate and zirconium carbonate added is m (TiO2) :m (碳酸锂) :m (碳酸锆) =90-100:70-90:10-20, and the fineness of zirconium carbonate and lithium carbonate needs to be controlled, and the residue on the 100-mesh sieve needs to be ≤0.1%;

[0036] In step d, TiO 2 The mass ratio of isopropanol, acrylamide and aluminum sol added is m(TiO 2 ): m (isopropanol): m (acrylamide): m (aluminum sol) = 900-1000: 5-10: 5-8: 3-6, and the stirring and mixing time is not less than 2h.

[0037] m (TiO2) :m (锂盐) :m (碳酸锆) If the lithium salt content is too small, the crystal form will be incomplete and contain more impurities.

[0038] Step a: The method for preparing the titanic acid slurry comprises preparing a slurry A with titanic acid, heating the slurry A to 50-70° C., adding concentrated ammonia water under stirring, controlling the pH value to be in the range of 7.0-9.0, and aging for 2-3 hours.

[0039] Titanic acid can be obtained from the production process of titanium dioxide using the sulfuric acid method.

[0040] The raw material metatitanic acid contains a large amount of sulfuric acid. Ammonia water is used to neutralize the sulfuric acid to avoid the reaction and dissolution of zirconium carbonate and lithium carbonate with sulfuric acid when zirconium carbonate and lithium carbonate are added later, thus saving materials.

[0041] TiO in slurry A in step a 2The concentration is 300-500g / L.

[0042] Step b: washing with water until the conductivity of the filtrate is less than 100 μS / cm, preferably 60-95 μS / cm.

[0043] In step b, the TiO 2 Concentration 500~600g / L.

[0044] The mass concentration of the ethanol aqueous solution in step f is 55-65%, and the temperature is 35-55°C.

[0045] In step i, the calcined microspheres are (微珠) :m (去离子水) =1:(2-4) in deionized water at 50-65°C, dilute acid solution is slowly added to the deionized water, and the pH value is controlled between 1.0 and 2.0 at the end point of the addition. After the pH value stabilizes, the microbeads are separated to obtain activated lithium zirconate titanate lithium ion sieve microbeads.

[0046] The dilute acid solution used for activation is a 15-25% dilute sulfuric acid solution or a 15-25% dilute hydrochloric acid solution. The activation operation is repeated 2 to 3 times to obtain fully activated lithium zirconate titanate lithium ion sieve microbeads.

[0047] The invention also discloses a lithium zirconate titanate lithium ion sieve obtained by the preparation method.

[0048] The present invention also discloses an application of the lithium zirconate titanate lithium ion sieve in separating lithium from salt lake brine. The lithium zirconate titanate lithium ion sieve is placed in the salt lake brine, and after the pH value of the brine remains unchanged, the lithium zirconate titanate lithium ion sieve with lithium extracted is separated, and lithium is removed to obtain a lithium-rich solution and a regenerated lithium zirconate titanate lithium ion sieve.

[0049] The application process specifically includes the following steps:

[0050] In step j, the salt lake brine needs to be filtered to remove impurities before use to make it clear, so as to avoid particulate impurities or colloidal impurities from mixing into the ion sieve microbeads, thereby affecting the lithium extraction efficiency.

[0051] Step h. After activating the lithium zirconate titanate lithium ion sieve, place it into salt lake brine, and after the pH value of the brine remains unchanged, separate the lithium zirconate titanate lithium ion sieve from which lithium has been extracted.

[0052] Step k. Immerse the lithium zirconate titanate lithium ion sieve microbeads after lithium extraction in deionized water at 50-65° C., slowly add a dilute acid solution to the deionized water, and control the pH value between 1.0 and 2.0 at the end point of the addition. After the pH stabilizes, take out the lithium zirconate titanate lithium ion sieve after lithium extraction, and obtain a lithium-rich solution with a high lithium content and a regenerated lithium zirconate titanate lithium ion sieve.

[0053] In step k, the ratio of ion sieve microbeads to deionized water is preferably m (离子筛) :m (去离子水) =(1-2):(1-2). The added dilute acid solution is a 15-25% dilute sulfuric acid solution or a 15-25% dilute hydrochloric acid solution.

[0054] Compared with the Chinese patent application with publication number CN117983178A, the lithium zirconate titanate lithium ion sieve of the present application has lower dissolution loss and longer service life during desorption and regeneration. The millimeter-sized particles prepared by the present invention can be directly loaded into the loading tower for use, and the water flow is good without clogging.

[0055] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0056] (1) Compared with the manganese-based ion sieve, the aluminum-based ion sieve and the perovskite-based ion sieve, which have dissolution losses during the adsorption and analysis process, the lithium ion sieve prepared by the present invention has basically no dissolution losses during use, has a longer service life, and can be recycled for more than 9,000 times. In addition, the ion sieve has a higher adsorption capacity, and the lithium ion concentration in the lithium-rich solution after delithiation is >16 g / L.

[0057] (2) Compared with conventional powder-type lithium extraction agents, in the process of industrial lithium extraction and delithiation, firstly, they cannot be directly loaded into the reaction tower for use, the powder is directly piled too tightly without gaps, and water cannot pass through. Secondly, if a plate frame is used for solid-liquid separation, some nano-scale powders will flow away with the water flow, and complete solid-liquid separation cannot be achieved, resulting in waste of materials, and secondary processing into plastic particles is required for production and use. The lithium ion sieve prepared by the present invention is formed into 3mm-4mm micro-beads by a single calcination, and can be directly separated from the solid and liquid after conventional stirring for lithium extraction, so as to achieve complete solid-liquid separation. It can also be loaded into the reaction tower for direct use, which greatly saves production costs.

[0058] (3) The ion sieve microbeads prepared by the present invention are regular spherical in shape and have high strength after high-temperature calcination. They are not easy to disperse or deform. After filling and use, water flows more smoothly without the phenomenon of "short circuit" of water channels, and the lithium extraction efficiency is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a photo of a lithium zirconate titanate lithium ion sieve prepared in one embodiment of the present invention. DETAILED DESCRIPTION

[0060] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0061] Example 1

[0062] Titanium dioxide is prepared from metatitanic acid in the production process of sulfuric acid method titanium dioxide. 2 The content of the slurry is 300g / L, the slurry is heated to 50℃, concentrated ammonia water is slowly added under stirring, the pH value is controlled to 7.0, and the slurry is aged for 2 hours. The slurry is filtered and washed with water until the conductivity of the filtrate is 92μS / cm, and then the washing is stopped. The filter cake is prepared into TiO 2 The content is 500g / L slurry. After stirring evenly, lithium carbonate and zirconium carbonate are added in sequence, with a mass ratio of m (TiO2) :m (碳酸锂) :m (碳酸锆) =100:70:10, after stirring for 1h, add isopropanol, acrylamide and aluminum sol in turn, with a mass ratio of m (TiO2) :m (异丙醇) :m (丙烯酰胺) :m (铝溶胶) =1000:5:5:3, after stirring for 2 hours, the slurry was dripped into a mixture of polymethyl silicone oil and polyether silicone oil containing phenylacetyl at 70°C in the form of liquid drops, wherein phenylacetyl was 10wt%, polymethyl silicone oil was 60wt%, and polyether silicone oil was 30wt%. The separated precursor rubber balls were washed with a 60% ethanol aqueous solution at 50°C; the precursor rubber balls were dried at 120°C for 2h, and the dried precursor rubber balls were calcined at 400°C for 2h and at 800°C for 3h in a rotary kiln to obtain lithium zirconate titanate ion sieve microbeads; the ion sieve microbeads were calcined at m (微珠) :m (去离子水) =1:3 ratio into 50 ℃ deionized water, slowly add 20% dilute sulfuric acid solution under stirring, when pH is maintained stable at 2.0, separate the ion sieve microbeads, repeat this operation twice to obtain fully activated lithium zirconate titanate lithium ion sieve microbeads, such as Figure 1 As shown; the ion sieve microbeads were placed in the clarified salt lake brine, and after the pH value of the brine decreased and remained unchanged, the ion sieve microbeads were separated and washed with deionized water. The lithium ion adsorption capacity can reach 45 mg / g; the washed ion sieve microbeads after lithium extraction were washed with m (离子筛) :m (去离子水) =1:1 into deionized water, slowly add 20% dilute sulfuric acid solution into the deionized water, control the titration endpoint pH to 2.0, and after the pH stabilizes, take out the lithium-free lithium zirconate titanate lithium ion sieve to obtain a lithium-rich solution with a high lithium content and a regenerated lithium zirconate titanate lithium ion sieve.

[0063] Example 2

[0064] Titanium dioxide is prepared from metatitanic acid in the production process of sulfuric acid method titanium dioxide. 2The content of the slurry is 400g / L, the slurry is heated to 60℃, concentrated ammonia water is slowly added under stirring, the pH value is controlled to 8.0, and the slurry is aged for 2 hours. The slurry is filtered and washed with water until the conductivity of the filtrate is 75μS / cm, and then the washing is stopped. The filter cake is prepared into TiO 2 The content is 550g / L slurry. After stirring evenly, lithium carbonate and zirconium carbonate are added in sequence, with a mass ratio of m (TiO2) :m (碳酸锂) :m (碳酸锆) =100:80:20, after stirring for 1h, add isopropanol, acrylamide and aluminum sol in turn, with a mass ratio of m (TiO2) :m (异丙醇) :m (丙烯酰胺) :m (铝溶胶) =1000:8:6:4, after stirring for 2 hours, the slurry was dripped into a mixture of polymethyl silicone oil and polyether silicone oil containing phenylacetyl at 80°C in the form of liquid drops, wherein phenylacetyl was 10wt%, polymethyl silicone oil was 65wt%, and polyether silicone oil was 25wt%. The separated precursor rubber balls were washed with a 60% ethanol aqueous solution at 60°C; the precursor rubber balls were dried at 130°C for 2 hours, and the dried precursor rubber balls were calcined at 500°C for 1 hour and at 850°C for 2 hours in a rotary kiln to obtain lithium zirconate titanate ion sieve microbeads; the ion sieve microbeads were calcined at m (微珠) :m (去离子水) =1:3 is placed in 60°C deionized water, and 20% dilute sulfuric acid solution is slowly added under stirring. When the pH is maintained stable at 1.5, the ion sieve microbeads are separated, and this operation is repeated twice to obtain fully activated lithium zirconate titanate lithium ion sieve microbeads; the ion sieve microbeads are placed in clarified salt lake brine, and when the pH value of the brine decreases and remains unchanged, the ion sieve microbeads are separated and washed with deionized water. The lithium ion adsorption amount can reach 46 mg / g; the ion sieve microbeads washed after lithium extraction are washed with m (离子筛) :m (去离子水) =1:1 into deionized water, slowly add 20% dilute sulfuric acid solution into the deionized water, control the titration endpoint pH to 1.5, and after the pH stabilizes, take out the lithium-free lithium zirconate titanate lithium ion sieve to obtain a lithium-rich solution with a high lithium content and a regenerated lithium zirconate titanate lithium ion sieve.

[0065] Example 3

[0066] Titanium dioxide is prepared from metatitanic acid in the production process of sulfuric acid method titanium dioxide. 2 The content of the slurry is 500g / L, the slurry is heated to 70℃, concentrated ammonia water is slowly added under stirring, the pH value is controlled to 9.0, and the slurry is aged for 2 hours. The slurry is filtered and washed with water until the conductivity of the filtrate is 60μS / cm, and then the washing is stopped; the filter cake is prepared into TiO 2The content is 600g / L slurry. After stirring evenly, lithium carbonate and zirconium carbonate are added in sequence, with a mass ratio of m (TiO2) :m (碳酸锂) :m (碳酸锆) =100:90:30, after stirring for 1h, add isopropanol, acrylamide and aluminum sol in turn, with a mass ratio of m (TiO2) :m (异丙醇) :m (丙烯酰胺) :m (铝溶胶) =1000:10:8:6, after stirring for 2 hours, the slurry was dripped into a mixture of polymethyl silicone oil and polyether silicone oil containing phenylacetyl at 90°C in the form of liquid drops, wherein phenylacetyl was 10wt%, polymethyl silicone oil was 70wt%, and polyether silicone oil was 20wt%. The separated precursor rubber balls were washed with a 60% ethanol aqueous solution at 70°C; the precursor rubber balls were dried at 140°C for 2 hours, and the dried precursor rubber balls were calcined at 600°C for 1 hour and at 900°C for 2 hours in a rotary kiln to obtain lithium zirconate titanate ion sieve microbeads; the ion sieve microbeads were calcined at m (微珠) :m (去离子水) =1:3 is placed in deionized water at 65°C, and a 20% dilute sulfuric acid solution is slowly added under stirring. When the pH is maintained stable at 1.0, the ion sieve microbeads are separated, and this operation is repeated twice to obtain fully activated lithium zirconate titanate lithium ion sieve microbeads; the ion sieve microbeads are placed in clarified salt lake brine, and when the pH value of the brine decreases and remains unchanged, the ion sieve microbeads are separated, and the ion sieve microbeads are washed with deionized water, and the lithium ion adsorption amount can reach 44 mg / g; the ion sieve microbeads washed after lithium extraction are washed with m (离子筛) :m (去离子水) =1:1 into deionized water, slowly add 20% dilute sulfuric acid solution into the deionized water, control the titration endpoint pH to be 1.0, and after the pH stabilizes, take out the lithium-free lithium zirconate titanate lithium ion sieve to obtain a lithium-rich solution with a high lithium content and a regenerated lithium zirconate titanate lithium ion sieve.

[0067] Some results in the example process were tested, wherein the ion concentration was the result of Agilent ICP-OES test.

[0068] Table 1: Partial test data of Example 1

[0069]

[0070] Table 2: Partial test data of Example 2

[0071]

[0072] Table 3: Partial test data of Example 3

[0073]

Claims

1. A method for preparing a lithium zirconate titanate lithium ion sieve, characterized in that: The following steps are involved: Step a. preparing titanate slurry; Step b. filtering the titanate slurry in step a, washing with water to obtain a filter cake, and adding a lithium salt solution to the filter cake to prepare a slurry C; Step c. Add zirconium carbonate and lithium carbonate to the slurry C obtained in step b, stir evenly to obtain slurry D; Step d. Add isopropanol, acrylamide and aluminum sol to slurry D and stir evenly to obtain slurry E; Step e. adding an initiator to a mixed solution of polymethyl silicone oil and polyether silicone oil and heating the mixture, and then dripping slurry E into the mixture in the form of droplets to obtain ion sieve precursor colloid balls; Step f. Washing the precursor colloid ball in step e with an ethanol aqueous solution; Step g. Drying the cleaned precursor rubber balls; Step h. placing the dried precursor rubber balls into a rotary kiln for calcination; Step i. Step h: adding a dilute acid solution to activate the microbeads obtained after calcination.

2. The method for preparing the lithium zirconate titanate lithium ion sieve according to claim 1, characterized in that: In step e, the mass ratio of polymethyl silicone oil to polyether silicone oil in the mixed solution of polymethyl silicone oil and polyether silicone oil is 50-70wt%:20-50wt%; preferably, the mass ratio of polymethyl silicone oil to polyether silicone oil in the mixed solution of polymethyl silicone oil and polyether silicone oil is 60-70wt%:20-40wt%.

3. The method for preparing the lithium zirconate titanate lithium ion sieve according to claim 1, characterized in that: In step e, the heating temperature is 70-90°C.

4. The method for preparing the lithium zirconate titanate lithium ion sieve according to claim 1, characterized in that: In step e, the droplet diameter of slurry E is 4 mm to 5 mm.

5. The method for preparing the lithium zirconate titanate lithium ion sieve according to claim 1, characterized in that: In step h, calcination is carried out in two steps, first calcination at 400-600° C. for 1-2 hours, and then calcination at 800-900° C. for 2-3 hours.

6. The method for preparing the lithium zirconate titanate lithium ion sieve according to claim 1, characterized in that: In step g, the drying temperature is 120-140° C. and the drying time is not less than 2 hours.

7. The method for preparing the lithium zirconate titanate lithium ion sieve according to any one of claims 1 to 6, characterized in that: In step e, the initiator is a mixture of one or more of benzoyl, phenylacetyl and styrene; preferably, the mass percentage of the initiator is 5 to 15 wt %.

8. The method for preparing the lithium zirconate titanate lithium ion sieve according to any one of claims 1 to 6, characterized in that: In step c, the added lithium salt is lithium carbonate, and the mass ratio of TiO2, added lithium carbonate and zirconium carbonate in the metatitanic acid slurry is m (TiO2) :m (碳酸锂) :m (碳酸锆) =90-100:70-90:10-20, and the fineness of zirconium carbonate and lithium carbonate needs to be controlled, and the residue on the 100-mesh sieve needs to be ≤0.1%; In step d, the mass ratio of TiO2, added isopropanol, acrylamide and aluminum sol in the titanic acid slurry is m (TiO2) :m (异丙醇) :m (丙烯酰胺) :m (铝溶胶) =900-1000:5-10:5-8:3-6, and the stirring and mixing time is not less than 2h.

9. A lithium zirconate titanate lithium ion sieve prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the lithium zirconate titanate lithium ion sieve prepared by the preparation method according to any one of claims 1 to 8 or the lithium zirconate titanate lithium ion sieve according to claim 9 in separating lithium from salt lake brine, characterized in that: The lithium zirconate titanate lithium ion sieve is placed in salt lake brine, and after the pH value of the brine remains unchanged, the lithium zirconate titanate lithium ion sieve with lithium extracted is separated, and lithium is removed to obtain a lithium-rich solution and a regenerated lithium zirconate titanate lithium ion sieve.

Images