Titanium-based lithium extraction adsorbent, preparation method and application thereof

Abstract

The application belongs to the technical field of lithium extraction, and particularly relates to a titanium-based lithium extraction adsorbent and a preparation method and application thereof. The preparation method provided by the application comprises the following steps: a) mixing and grinding a lithium compound, a titanium compound, a zirconium compound, a niobium compound, an iron compound, a pore former and water, and drying to obtain a mixed powder; b) placing the mixed powder in a calcination device, first heating from ambient temperature to a first temperature at a first heating rate, then heating from the first temperature to a second temperature at a second heating rate, and calcining at the second temperature to obtain a precursor powder; c) granulating the precursor powder to obtain activated adsorbent particles; and d) placing the activated adsorbent particles in an acid solution for activation treatment to obtain the titanium-based lithium extraction adsorbent. The preparation method provided by the application can improve the adsorption capacity, ion selectivity and structural stability of the lithium extraction adsorbent, reduce the solution loss of the lithium extraction adsorbent, and prolong the service life of the lithium extraction adsorbent.

Description

Technical Field

[0001] This invention belongs to the field of lithium extraction technology, and particularly relates to a titanium-based lithium extraction adsorbent, its preparation method, and its application. Background Technology

[0002] Lithium, the lightest metallic element in nature with the lowest standard electrode potential, is hailed as the "white oil" of the future and is considered the ideal battery material. With the development of new energy power and new energy vehicles, the demand for energy storage batteries and automotive batteries is rapidly increasing, and traditional lithium extraction from lithium ore can no longer meet market demand. Furthermore, lithium is abundant in natural salt lake brines, accounting for approximately 61% of total lithium resources. How to efficiently extract lithium from salt lakes has become a problem that experts both domestically and internationally are dedicated to solving.

[0003] Salt lake brine generally contains Li + Na + K + Ca 2+ Mg 2+ B 3+ SO4 2- Cl - CO3 2- Plasma is currently the main process for extracting lithium from salt lakes, including precipitation, adsorption, extraction, membrane separation, and combinations of these methods. Among them, the adsorption method combined with membrane separation is currently the most suitable for salt lakes in my country with high magnesium and sodium content. The performance of the adsorbent is the key to lithium extraction technology.

[0004] Currently, commonly used adsorbents include aluminum-based, titanium-based, and manganese-based adsorbents. Aluminum-based adsorbents have low adsorption capacity and are suitable for acidic brine in salt lakes. Manganese-based adsorbents have high adsorption capacity but high solubility, making them difficult to apply in engineering. Titanium-based adsorbents have adsorption capacity and solubility between aluminum-based and manganese-based adsorbents, making them suitable for alkaline or neutral brine in salt lakes, and more suitable for the currently planned development of salt lakes in Tibet. Developing titanium-based adsorbents that can further improve adsorption capacity, enhance lithium-ion selective adsorption, reduce magnesium and sodium ion adsorption, decrease solubility, and extend service life has become a pressing issue for the industry. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a titanium-based lithium extraction adsorbent, its preparation method and application. The preparation method provided by this invention can improve the adsorption capacity, ion selectivity and structural stability of the lithium extraction adsorbent, reduce the solubility loss of the lithium extraction adsorbent and extend its service life.

[0006] This invention provides a method for preparing a titanium-based lithium extraction adsorbent, comprising the following steps:

[0007] a) Lithium compound, titanium compound, zirconium compound, niobium compound, iron compound, pore-forming agent and water are mixed, ground and dried to obtain a mixed powder;

[0008] In step a), the molar ratio of Li in the lithium compound, Ti in the titanium compound, Zr in the zirconium compound, Nb in the niobium compound, and Fe in the iron compound is 2:(0.7–0.92):(0.02–0.15):(0.02–0.15):(0.02–0.15); the pore-forming agent includes ammonium sulfate and ammonium bicarbonate; the amount of the pore-forming agent is 5–10 wt% of the total mass of the lithium compound, titanium compound, zirconium compound, niobium compound, and iron compound.

[0009] b) The mixed powder is placed in a calcination device, and the temperature is first raised from the ambient temperature to the first temperature at a first heating rate, and then raised from the first temperature to the second temperature at a second heating rate, and calcined at the second temperature to obtain the precursor powder.

[0010] In step b), the first heating rate is 15–20 °C / min; the first temperature is 250–350 °C; the second heating rate is 2–10 °C / min; and the second temperature is 750–850 °C.

[0011] c) Granulate the precursor powder to obtain adsorbent particles to be activated;

[0012] d) The adsorbent particles to be activated are placed in an acid solution for activation treatment to obtain a titanium-based lithium extraction adsorbent.

[0013] Preferably, in step a), the lithium compound is one or more of lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate, and lithium chloride; the titanium compound is one or more of titanium dioxide, metatitanic acid, and titanium tetrachloride; the zirconium compound is zirconium oxide and / or zirconium nitrate; the niobium compound is one or more of niobium oxide, niobium nitrate, and niobium carbonate; and the iron compound is one or more of ferric oxide, iron(II,III) oxide, and ferric nitrate.

[0014] Preferably, in step b), the heat preservation and calcination time is 6 to 10 hours.

[0015] Preferably, step c) specifically includes:

[0016] c1) The precursor powder and colloidal solution are mixed to obtain a granulated slurry;

[0017] c2) The granulation slurry is sprayed into the molding solution to form granules by spraying.

[0018] c3) The particles are dried to obtain adsorbent particles to be activated.

[0019] Preferably, in step c1), the colloidal solution comprises a polymeric material and an organic solvent; the polymeric material is one or more of polyvinyl butyral, polyvinyl alcohol, polyvinyl chloride, polyethylene glycol, polyvinylidene fluoride, ethyl cellulose, and hydroxyethyl cellulose; the organic solvent is one or more of dicarboxylic acid ester, N,N-dimethylacetamide, propylene glycol methyl ether acetate, N,N-dimethylformamide, ethylene glycol tert-butyl ether, propylene glycol methyl ether, dimethyl sulfoxide, tetrahydrofuran, and isopropyl acetate; the mass-to-volume ratio of the polymeric material to the organic solvent is (5-50) g: 100 mL; the mass-to-volume ratio of the precursor powder to the organic solvent is (1000-2500) g: 2.5 L.

[0020] Preferably, in step c2), the molding solution is an aqueous solution containing an additive; the additive is one or more of methanol, ethanol, propanol, isobutanol, n-butanol, acetone, cyclohexanone, and butanone; the content of the additive in the molding solution is 1-50 vol%.

[0021] Preferably, in step c2), the particle size is 0.3 to 0.8 mm.

[0022] Preferably, in step d), the adsorbent particles to be activated are first subjected to heat curing before activation treatment; the heat curing temperature is 150-180℃; and the heat curing time is 2-6 hours.

[0023] This invention provides a titanium-based lithium extraction adsorbent, which is prepared according to the preparation method described in the above technical solution.

[0024] This invention provides a method for lithium extraction from water, comprising the following steps:

[0025] The titanium-based lithium extraction adsorbent described in the above technical solution is used to adsorb and extract lithium from water.

[0026] Compared with existing technologies, this invention provides a titanium-based lithium extraction adsorbent, its preparation method, and its application. The preparation method provided by this invention includes the following steps: a) mixing and grinding a lithium compound, a titanium compound, a zirconium compound, a niobium compound, an iron compound, a pore-forming agent, and water, then drying to obtain a mixed powder; in step a), the molar ratio of Li in the lithium compound, Ti in the titanium compound, Zr in the zirconium compound, Nb in the niobium compound, and Fe in the iron compound is 2:(0.7~0.92):(0.02~0.15):(0.02~0.15):(0.02~0.15); the pore-forming agent includes ammonium sulfate and ammonium bicarbonate; the amount of the pore-forming agent is [amount missing] of the total mass of the lithium compound, titanium compound, zirconium compound, niobium compound, and iron compound. a) The mixed powder is placed in a calcining device, and the temperature is first raised from the ambient temperature to a first temperature at a first heating rate, and then raised from the first temperature to a second temperature at a second heating rate, and calcined at the second temperature to obtain precursor powder; in step b), the first heating rate is 15-20℃ / min; the first temperature is 250-350℃; the second heating rate is 2-10℃ / min; the second temperature is 750-850℃; c) The precursor powder is granulated to obtain adsorbent particles to be activated; d) The adsorbent particles to be activated are placed in an acid solution for activation treatment to obtain a titanium-based lithium extraction adsorbent. The method provided by the present invention mixes lithium compounds, titanium compounds, zirconium compounds, niobium compounds and iron compounds in a certain proportion and then calcines them to generate the precursor Li2Ti. X Zr Y Nb z Fe 4 / 3(1-X-Y-Z) O3; then the precursor is granulated to obtain adsorbent particles; subsequently, the Li in the adsorbent is activated by replacing it with hydrogen in an acid solution, enabling it to adsorb Li from water. The generated precursor, Li2Ti, is... X Zr Y Nb z Fe 4 / 3(1-X-Y-Z) After acid substitution, the more positively charged Fe, Zr, and Nb elements of O3 align in Li2Ti. X Zr Y Nb z Fe 4 / 3(1-X-Y-Z) O3 lattice surface, relative to monovalent Li + It is more likely to repel divalent Mg 2+ This improves the adsorbent's ability to adsorb Li + / Mg 2+ The selectivity is achieved by adding ammonium sulfate and ammonium bicarbonate as pore-forming agents before calcination. During calcination, ammonium sulfate and ammonium bicarbonate decompose into gases such as SO2, N2, H2O, and CO2, which are then released, thus enabling the calcined Li2Ti to be pore-forming.X Zr Y Nb z Fe 4 / 3(1-X-Y-Z) The O3 precursor has a loose porous structure, which helps to reduce the adsorption of Li by the adsorbent. + This reduces mass transfer resistance, increases adsorption capacity and rate, and because ammonium sulfate and ammonium bicarbonate decompose at different rates and produce different gases, choosing these two components as porogens helps to form a rich and unique pore structure inside the precursor, which is beneficial for improving the Li- content of the adsorbent. + Adsorption properties; rapid heating in the low-temperature range during calcination facilitates the rapid decomposition and removal of the pore-forming agent, thereby enhancing the adsorption performance of Li₂Ti. X Zr Y Nb z Fe 4 / 3(1-X-Y-Z) The richer porous structure of the O3 precursor and the reduced heating rate in the high-temperature range contribute to the stability of the precursor lattice, thereby reducing adsorbent solubility and extending its service life. In summary, the preparation method provided by this invention can significantly improve the adsorption capacity, ion selectivity, and structural stability of lithium extraction adsorbents, reduce solubility, and extend their service life, showing broad application prospects in the field of lithium extraction from salt lakes. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a method for preparing a titanium-based lithium extraction adsorbent, comprising the following steps:

[0029] a) Lithium compound, titanium compound, zirconium compound, niobium compound, iron compound, pore-forming agent and water are mixed, ground and dried to obtain a mixed powder;

[0030] b) The mixed powder is placed in a calcination device, and the temperature is first raised from the ambient temperature to the first temperature at a first heating rate, and then raised from the first temperature to the second temperature at a second heating rate, and calcined at the second temperature to obtain the precursor powder.

[0031] c) Granulate the precursor powder to obtain adsorbent particles to be activated;

[0032] d) The adsorbent particles to be activated are placed in an acid solution for activation treatment to obtain a titanium-based lithium extraction adsorbent.

[0033] In the preparation method provided by the present invention, in step a), the lithium compound is preferably one or more of lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate, and lithium chloride; the preferred titanium compound is one or more of titanium dioxide, metatitanic acid, and titanium tetrachloride; the zirconium compound is preferably zirconium oxide and / or zirconium nitrate; the niobium compound is preferably one or more of niobium oxide, niobium nitrate, and niobium carbonate; and the iron compound is preferably one or more of ferric oxide, iron(II,III) oxide, and ferric nitrate.

[0034] In the preparation method provided by this invention, in step a), the molar ratio of Li in the lithium compound, Ti in the titanium compound, Zr in the zirconium compound, Nb in the niobium compound, and Fe in the iron compound is 2:(0.7~0.92):(0.02~0.15):(0.02~0.15):(0.02~0.15); wherein, the molar ratio of Li in the lithium compound and Ti in the titanium compound can specifically be 2:0.7, 2:0.71, 2:0.72, or 2:0.73. The molar ratios of Li in the lithium compound and Zr in the zirconium compound can be 2:0.74, 2:0.75, 2:0.76, 2:0.77, 2:0.78, 2:0.79, 2:0.8, 2:0.81, 2:0.82, 2:0.83, 2:0.84, 2:0.85, 2:0.86, 2:0.87, 2:0.88, 2:0.89, 2:0.9, 2:0.91, or 2:0.92; specifically, the molar ratio of Li in the lithium compound and Zr in the zirconium compound can be 2:0.02, 2:0.03, or 2:0. The molar ratios of Li in the lithium compound and Nb in the niobium compound can be 2:0.04, 2:0.05, 2:0.06, 2:0.07, 2:0.072, 2:0.08, 2:0.09, 2:0.1, 2:0.11, 2:0.12, 2:0.13, 2:0.14, or 2:0.15; specifically, the molar ratio of Li in the lithium compound and Nb in the niobium compound can be 2:0.02, 2:0.03, 2:0.034, 2:0.04, 2:0.05, 2:0.06, 2:0.07, 2:0.08, or 2:0.15. 09, 2:0.1, 2:0.11, 2:0.12, 2:0.13, 2:0.14 or 2:0.15; the molar ratio of Li in the lithium compound and Fe in the iron compound can specifically be 2:0.02, 2:0.03, 2:0.04, 2:0.05, 2:0.058, 2:0.06, 2:0.07, 2:0.08, 2:0.09, 2:0.1, 2:0.11, 2:0.12, 2:0.13, 2:0.14 or 2:0.15.

[0035] In the preparation method provided by the present invention, in step a), the pore-forming agent includes ammonium sulfate and ammonium bicarbonate; the mass ratio of ammonium sulfate to ammonium bicarbonate is preferably (0.5-2):1, specifically 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.03:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1.

[0036] In the preparation method provided by the present invention, in step a), the amount of the pore-forming agent is 5 to 10 wt% of the total mass of the lithium compound, titanium compound, zirconium compound, niobium compound and iron compound, specifically 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt% or 10 wt%.

[0037] In the preparation method provided by the present invention, in step a), the amount of water is preferably 40-70 wt% of the total mass of the lithium compound, titanium compound, zirconium compound, niobium compound and iron compound, specifically 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt%, 60 wt%, 61 wt%, 62 wt%, 63 wt%, 64 wt%, 65 wt%, 66 wt%, 67 wt%, 68 wt%, 69 wt%, or 70 wt%.

[0038] In the preparation method provided by the present invention, in step a), the grinding time is preferably 3 to 6 hours, specifically 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours.

[0039] In the preparation method provided by the present invention, in step a), the drying temperature is preferably 95-110℃, specifically 95℃, 96℃, 97℃, 98℃, 99℃, 100℃, 101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃ or 110℃; the drying time is not particularly limited, and drying to constant weight is sufficient.

[0040] In the preparation method provided by this invention, in step b), the first heating rate is 15-20℃ / min, specifically 15℃ / min, 16℃ / min, 17℃ / min, 18℃ / min, 19℃ / min, or 20℃ / min; the first temperature is 250-350℃, specifically 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, 295℃, 300℃, 305℃, 310℃, 315℃, 320℃, 325℃, 330℃, 335℃, 340℃, 345℃, or 350℃; the second heating rate is 2-10℃ / min, specifically 2℃ / min. The heating rate is 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, or 10℃ / min; the second temperature is 750~850℃, specifically 750℃, 755℃, 760℃, 765℃, 770℃, 775℃, 780℃, 785℃, 790℃, 795℃, 800℃, 805℃, 810℃, 815℃, 820℃, 825℃, 830℃, 835℃, 840℃, 845℃, or 850℃; the heat preservation and calcination time is preferably 6~10h, specifically 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, or 10h.

[0041] In the preparation method provided by the present invention, step c) preferably includes the following steps:

[0042] c1) The precursor powder and colloidal solution are mixed to obtain a granulated slurry;

[0043] c2) The granulation slurry is sprayed into the molding solution to form granules by spraying.

[0044] c3) The particles are dried to obtain adsorbent particles to be activated.

[0045] In the preparation method provided by this invention, in step c1), the colloidal solution preferably comprises a polymeric material and an organic solvent; wherein, the polymeric material is preferably one or more selected from polyvinyl butyral (PVB), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polyethylene glycol (PEG), polyvinylidene fluoride (PVDF), ethyl cellulose (EC), and hydroxyethyl cellulose (HEC); and the organic solvent is preferably dicarboxylic acid ester (DBE), N,N-dimethylacetamide (DMA), propylene glycol methyl ether acetate (PMA), N,N One or more of dimethylformamide (DMF), ethylene glycol tert-butyl ether (ETB), propylene glycol methyl ether (PM), dimethyl sulfoxide (DMSO), tetrahydrofuran, and isopropyl acetate; the polyvinylidene fluoride is preferably PVDF5000; the mass-to-volume ratio of the polymeric material to the organic solvent is preferably (5-50) g:100 mL, specifically 5 g:100 mL, 6 g:100 mL, 7 g:100 mL, 8 g:100 mL, 9 g:100 mL, 10 g:100 mL, 11 g:100 mL, 12 g:100 mL, etc. g:100mL, 13g:100mL, 14g:100mL, 15g:100mL, 16g:100mL, 17g:100mL, 18g:100mL, 19g:100mL, 20g:100mL, 21g:100mL , 22g:100mL, 23g:100mL, 24g:100mL, 25g:100mL, 26g:100mL, 27g:100mL, 28g:100mL, 29g:100mL, 30g:100mL, 31g:10 0mL, 32g:100mL, 33g:100mL, 34g:100mL, 35g:100mL, 36g:100mL, 37g:100mL, 38g:100mL, 39g:100mL, 40g:100mL, 41g :100mL, 42g:100mL, 43g:100mL, 44g:100mL, 45g:100mL, 46g:100mL, 47g:100mL, 48g:100mL, 49g:100mL or 50g:100mL.

[0046] In the preparation method provided by the present invention, in step c1), the preferred mass-to-volume ratio of the precursor powder to the organic solvent in the colloidal solution is (1000-2500) g:2.5 L, specifically 1000 g:2.5 L, 1100 g:2.5 L, 1200 g:2.5 L, 1300 g:2.5 L, 1400 g:2.5 L, 1500 g:2.5 L, 1600 g:2.5 L, 1700 g:2.5 L, 1800 g:2.5 L, 1900 g:2.5 L, 2000 g:2.5 L, 2100 g:2.5 L, 2200 g:2.5 L, 2300 g:2.5 L, 2400 g:2.5 L, or 2500 g:2.5 L.

[0047] In the preparation method provided by this invention, in step c2), the molding solution is preferably an aqueous solution containing an additive; the additive is preferably one or more selected from methanol, ethanol, propanol, isobutanol, n-butanol, acetone, cyclohexanone, and butanone; the content of the additive in the molding solution is preferably 1-50 vol%, specifically 1 vol%, 2 vol%, 3 vol%, 4 vol%, 5 vol%, 6 vol%, 7 vol%, 8 vol%, 9 vol%, 10 vol%, 11 vol%, 12 vol%, 13 vol%, 14 vol%, 15 vol%, 16 vol%, 17 vol%, 18 vol%. %, 19vol%, 20vol%, 21vol%, 22vol%, 23vol%, 24vol%, 25vol%, 26vol%, 27vol%, 28vol%, 29vol%, 30vol%, 31vol%, 32vol%, 33vol%, 34vol% , 35vol%, 36vol%, 37vol%, 38vol%, 39vol%, 40vol%, 41vol%, 42vol%, 43vol%, 44vol%, 45vol%, 46vol%, 47vol%, 48vol%, 49vol% or 50vol%.

[0048] In the preparation method provided by the present invention, in step c2), the particle size is preferably 0.3 to 0.8 mm, specifically 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm or 0.8 mm.

[0049] In the preparation method provided by the present invention, in step c3), the drying temperature is preferably 95-105℃, specifically 95℃, 96℃, 97℃, 98℃, 99℃, 100℃, 101℃, 102℃, 103℃, 104℃ or 105℃; the drying time is preferably 2-12h, specifically 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h.

[0050] In the preparation method provided by the present invention, in step d), the adsorbent particles to be activated are preferably heated and cured before activation treatment; the heating and curing temperature is preferably 150-180℃, specifically 150℃, 155℃, 160℃, 165℃, 170℃, 175℃ or 180℃; the heating and curing time is preferably 2-6h, specifically 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h.

[0051] In the preparation method provided by this invention, in step d), the acid solution is one or more of hydrochloric acid solution, nitric acid solution, and sulfuric acid solution; the concentration of the acid solution is preferably 0.1–3 mol / L, specifically 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.7 mol / L, 1 mol / L, 1.2 mol / L, 1.5 mol / L, 1.7 mol / L, 2 mol / L, 2.3 mol / L, etc. The concentration is 2.5 mol / L, 2.7 mol / L, or 3 mol / L; the activation temperature is preferably 10–40℃, specifically 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, or 40℃; the activation time is preferably 10–24 h, specifically 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h, or 24 h.

[0052] The present invention also provides a titanium-based lithium extraction adsorbent, which is prepared according to the preparation method described in the above technical solution.

[0053] This invention also provides a method for lithium extraction from water, comprising the following steps:

[0054] The titanium-based lithium extraction adsorbent described in the above technical solution is used to adsorb and extract lithium from water.

[0055] The technical solution provided by this invention has at least the following advantages:

[0056] 1) By adding zirconium compounds, niobium compounds, and iron compounds to the source material for preparing titanium-based lithium extraction adsorbents, a precursor Li₂Ti was prepared. X ZrY Nb z Fe 4 / 3(1-X-Y-Z) After acidification, O3 forms a more positively charged array of Fe, Zr, and Nb on its crystal lattice surface, thereby repelling Mg from the brine. 2+ Improve Li / Mg selectivity;

[0057] 2) By adding a certain amount of ammonium sulfate and ammonium bicarbonate as pore-forming agents before calcination of the source material, combined with rapid heating in the low-temperature section during calcination, the resulting Li2Ti... X Zr Y Nb z Fe 4 / 3(1-X-Y-Z) O3 has a rich and unique porous structure, which helps to reduce Li. + Mass transfer resistance in the adsorption process, thereby increasing adsorption capacity and adsorption rate;

[0058] 3) During the high-temperature stage of the programmed temperature rise, reducing the heating rate helps improve the structural stability of the precursor, thereby reducing solubility loss and extending the service life of the adsorbent.

[0059] 4) The anti-solvent granulation method is preferred. By adjusting the proportion of additives in the molding solution used for anti-solvent granulation, the surface tension of the molding solution can be controlled, thereby controlling the size and shape of the adsorbent particles, so as to increase the specific surface area of ​​the adsorbent, increase the chance of effective sites in the adsorbent particles contacting the brine, and improve the adsorption capacity.

[0060] 5) After the shaped granules are dried, it is preferable to add a high-temperature curing step, which can improve the strength of the granules and reduce the amount of polymer binder used.

[0061] For clarity, the following examples and comparative models will be used to provide a detailed description.

[0062] Example 1

[0063] A method for preparing a titanium-based lithium extraction adsorbent includes the following steps:

[0064] 1) Mixing of source materials: 1000g of lithium carbonate powder, 919g of titanium dioxide powder, 120g of zirconium oxide powder, 50g of niobium oxide powder and 63.2g of iron oxide powder were premixed, with the corresponding molar ratio of Li:Ti:Zr:Nb:Fe = 2.00:0.85:0.072:0.034:0.058; then 1100mL of water, 103g of ammonium sulfate and 100g of ammonium bicarbonate were added, and the mixture was ground in a grinding jar for 3 hours; after grinding, the mixed slurry was taken out and dried in an oven at 105℃ until constant weight to obtain mixed powder.

[0065] 2) Precursor preparation: The dried mixed powder was placed in a muffle furnace and the heating program of the muffle furnace was set as follows: the heating rate was 20℃ / min in the 25~300℃ stage; the heating rate was 8℃ / min in the 300~800℃ stage; when the temperature reached 800℃, it was kept at that temperature for 8h; after the calcination was completed, it was allowed to cool naturally to room temperature to obtain the precursor powder.

[0066] 3) Granulation: Take 450g of PVDF 5000, add 2.5L of DMF solvent, and heat in a 70℃ water bath until completely dissolved to obtain a colloidal solution; add 1700g of the above precursor powder to the colloidal solution, and mechanically stir until uniformly mixed to obtain a granulation slurry; take 5L of water, add 2L of isobutanol to obtain a molding solution; use a rotary spraying method to drop the granulation slurry into the molding solution to form adsorbent particles (elliptical, particle size range 0.3~0.8mm), and then place the above adsorbent particles in an oven at 105℃ to dry for 6h.

[0067] 4) High-temperature curing and activation: The dried adsorbent particles were placed in an oven at 170°C for 4 hours to cure; the cured adsorbent particles were then removed and activated in a 2 mol / L sulfuric acid solution for 12 hours to obtain titanium-based lithium extraction adsorbent particles.

[0068] Comparative Example 1

[0069] Titanium-based lithium extraction adsorbent particles were prepared according to the method of Example 1, except that zirconium oxide powder, niobium oxide powder and iron oxide powder were not added when preparing the mixed powder.

[0070] Comparative Example 2

[0071] Titanium-based lithium extraction adsorbent particles were prepared according to the method in Example 1, except that the curing process in an oven at 170°C for 4 hours was omitted, i.e., the high-temperature curing process.

[0072] Comparative Example 3

[0073] Titanium-based lithium extraction adsorbent particles were prepared according to the method of Example 1, except that when preparing the mixed powder, the pore-forming agent used was changed from 103g of ammonium sulfate and 100g of ammonium bicarbonate to 210g of ammonium sulfate.

[0074] Comparative Example 4

[0075] Titanium-based lithium-extraction adsorbent particles were prepared according to the method in Example 1, except that when preparing the precursor powder, the heating rate was fixed at 10°C / min, and the temperature was raised from room temperature to 800°C. After holding at the temperature for 6 hours, the temperature was naturally cooled to room temperature.

[0076] Effect evaluation

[0077] Simulated Li in Zabuye Salt Lake brine + Na + K + Ca 2+ Mg 2+ B 3+ SO4 2- Cl - CO3 2- The content of the adsorbent was evaluated using four commercially available adsorbents, as well as the adsorption of the adsorbents prepared in Example 1 and Comparative Examples 1-4. The evaluation parameters included adsorption capacity, Li / Mg selectivity, Li / Na selectivity, and titanium dissolution loss. The experimental results are shown in Table 1.

[0078] Table 1. Evaluation results of adsorbent particles

[0079] Adsorbent source Adsorbent capacity, mg / g Li / Mg selectivity Li / Na selectivity Titanium dissolution, ‰ Manufacturer A 22.37 8.55 6.72 0.002 Manufacturer B 18.32 13.23 7.95 0.043 Manufacturer C 26.64 7.87 8.06 0.071 Manufacturer D 20.89 12.74 8.38 0.036 Example 1 35.78 15.61 9.48 0.002 Comparative Example 1 33.16 7.25 8.84 0.005 Comparative Example 2 36.02 15.73 9.89 0.035 Comparative Example 3 28.95 15.62 8.93 0.010 Comparative Example 4 26.75 13.27 7.59 0.023

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a titanium-based lithium-adsorbing adsorbent, characterized by, The method comprises the following steps: a) mixing, grinding and drying a lithium compound, a titanium compound, a zirconium compound, a niobium compound, an iron compound and a pore-forming agent to obtain a mixed powder; In step a), the molar ratio of Li in the lithium compound, Ti in the titanium compound, Zr in the zirconium compound, Nb in the niobium compound and Fe in the iron compound is 2:(0.7-0.92):(0.02-0.15):(0.02-0.15):(0.02-0.15); the pore-forming agent comprises ammonium sulfate and ammonium bicarbonate, and the mass ratio of the ammonium sulfate to the ammonium bicarbonate is (0.5-2):1; the amount of the pore-forming agent is 5-10 wt% of the total mass of the lithium compound, the titanium compound, the zirconium compound, the niobium compound and the iron compound; b) placing the mixed powder in a calcination device, first heating from ambient temperature to a first temperature at a first heating rate, then heating from the first temperature to a second temperature at a second heating rate, and calcining at the second temperature to obtain a precursor powder; In step b), the first heating rate is 15-20 ℃ / min; the first temperature is 250-350 ℃; the second heating rate is 2-10 ℃ / min; the second temperature is 750-850 ℃; and the calcining time is 6-10 h; c) granulating the precursor powder to obtain activated adsorbent particles; d) activating the activated adsorbent particles in an acid solution to obtain a titanium-based lithium extraction adsorbent.

2. The method according to claim 1, in step a), the lithium compound is one or more of lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate and lithium chloride; the titanium compound is one or more of titanium dioxide, metatitanic acid and titanium tetrachloride; the zirconium compound is zirconium oxide and / or zirconium nitrate; the niobium compound is one or more of niobium oxide, niobium nitrate and niobium carbonate; and the iron compound is one or more of diiron trioxide, magnetite and iron nitrate.

3. The preparation method according to claim 1, characterized in that, Step c) specifically comprises: c1) mixing the precursor powder and a colloidal solution to obtain a granulation slurry; c2) spraying the granulation slurry into a molding solution in a spraying manner to form particles; c3) drying the particles to obtain activated adsorbent particles.

4. The production method according to claim 3, characterized by, In step c1), the components of the colloidal solution include a high molecular material and an organic solvent; the high molecular material is one or more of polyvinyl butyral, polyvinyl alcohol, polyvinyl chloride, polyethylene glycol, polyvinylidene fluoride, ethyl cellulose and hydroxyethyl cellulose; the organic solvent is one or more of a dicarboxylic acid ester, N,N-dimethylacetamide, propylene glycol methyl ether acetate, N,N-dimethylformamide, ethylene glycol tert-butyl ether, propylene glycol methyl ether, dimethyl sulfoxide, tetrahydrofuran and isopropyl acetate; the mass-to-volume ratio of the high molecular material and the organic solvent is (5-50) g:100 mL; and the mass-to-volume ratio of the precursor powder and the organic solvent is (1000-2500) g:2.5 L.

5. The preparation method according to claim 3, characterized in that, In step c2), the forming solution is an aqueous solution containing an additive; the additive is one or more of methanol, ethanol, propanol, isobutyl alcohol, n-butyl alcohol, acetone, cyclohexanone and butanone; the content of the additive in the forming solution is 1-50 vol%.

6. The preparation method according to claim 3, characterized in that, In step c2), the particle size of the particles is 0.3-0.8 mm.

7. The preparation method of claim 1, in step d), the adsorbent particles to be activated are subjected to heat curing before being subjected to the activation treatment; the temperature of the heat curing is 150-180°C; the time of the heat curing is 2-6 h.

8. A titanium-based lithium-adsorbing adsorbent, characterized by, The titanium-based lithium-removing adsorbent is prepared according to the preparation method of any one of claims 1-7.

9. A method for extracting lithium from a water body, characterized in that, comprising the following steps: The titanium-based lithium-removing adsorbent of claim 8 is used to adsorb and remove lithium from a water body.