A kind of high-purity spherical titanium dioxide and preparation method thereof

Abstract

The invention discloses a high-purity spherical titanium dioxide and a preparation method thereof. The preparation method is as follows: firstly, titanium-containing blast furnace slag is crushed, ground and then sieved; then, it is mixed with a sulfuric acid solution and an additive for heating and reaction to obtain a solution containing impurity sulfuric acid titanyl; then, a polysuccinimide derivative is added for hydrothermal reaction to obtain hydrothermal metatitanic acid; then, it is mixed with a NaOH solution to form a slurry, filtered, washed and dried after reaction to obtain desulfurized metatitanic acid; finally, it is roasted and cooled to obtain the product. The invention uses titanium-containing blast furnace slag as a raw material, adopts a complexing agent, a surfactant and a dispersant in the process flow, effectively removes impurities, obtains a high-purity spherical titanium dioxide product, realizes the resource utilization of industrial waste, improves economic benefits, and has significant technical value and application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of titanium dioxide preparation, and in particular to high-purity spherical titanium dioxide and a preparation method thereof. Background Art

[0002] The titanium-containing blast furnace slag has a complex ore phase, contains a large amount of complex silicates, and the titanium-containing mineral grains are fine, mainly in a complex crystal structure, and it is difficult to improve its grade through effective ore dressing. Over the past few decades, many scholars have conducted extensive research on it, which can be roughly divided into pyrometallurgical processes and hydrometallurgical processes. The hydrometallurgical process mainly uses alkaline leaching or acid hydrolysis, and the acid hydrolysis agents commonly used are sulfuric acid and hydrochloric acid.

[0003] Chinese patent application document CN114014359A discloses a method for extracting titanium dioxide from titanium-containing blast furnace slag, comprising the following steps: A. drying the titanium-containing blast furnace slag and grinding it into powder to obtain blast furnace slag powder; B. adding sulfuric acid to the blast furnace slag powder and stirring it evenly, then adding hydrogen peroxide and letting it stand and soak to obtain a soaked mixture; C. separating the soaked mixture from solid and liquid, and washing the solid phase with hydrogen peroxide to obtain a hydrogen peroxide complex liquid; D. decomposing the hydrogen peroxide complex liquid to obtain titanium dioxide.

[0004] In the existing wet process, the hydrolyzed metatitanic acid obtained by acid hydrolysis of titanium-containing blast furnace slag has a large specific surface area and colloidal properties, which can easily adsorb impurity ions such as ferrous iron and carry them out with the metatitanic acid, affecting the final TiO 2 Purity of the product. Summary of the invention

[0005] In order to solve the shortcomings of the prior art, the purpose of the present invention is to provide a high-purity spherical titanium dioxide and a preparation method thereof, using titanium-containing blast furnace slag as raw material, and effectively removing impurities through acid hydrolysis, hydrothermal reaction, desulfurization and roasting, etc., to finally obtain a high-purity titanium dioxide product, thereby realizing the resource utilization of industrial waste and improving economic benefits, and having significant technical value and application prospects.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for preparing high-purity spherical titanium dioxide comprises the following steps:

[0008] (1) crushing, grinding and sieving titanium-containing blast furnace slag;

[0009] (2) mixing the sieved titanium-containing blast furnace slag with a sulfuric acid solution, adding citric acid and sodium dodecylbenzene sulfonate, heating for reaction, and obtaining an acid hydrolysis slag; adding the acid hydrolysis slag into deionized water, stirring and mixing, and filtering to obtain an impure sulfuric acid-containing titanium oxide solution;

[0010] (3) adding a titanium dioxide solution containing impurities of sulfuric acid and a polysuccinimide derivative into a reaction kettle, sealing the reaction kettle, cooling the product, filtering the product to obtain a filter cake, washing the filter cake, and drying the filter cake to obtain hydrothermal metatitanic acid;

[0011] (4) Mixing hydrothermal titanic acid and NaOH solution to form a slurry, adjusting the pH, stirring at room temperature, filtering, washing, and drying the product to obtain desulfurized titanic acid; calcining the desulfurized titanic acid, and cooling to obtain the high-purity spherical titanium dioxide.

[0012] Preferably, in step (1), the product is sieved through a 200-600 mesh sieve.

[0013] Preferably, in step (2), the concentration of the sulfuric acid solution is 85-98wt%; the heating reaction conditions are 70-130°C for 1-6h; the dosage ratio of the titanium-containing blast furnace slag to the sulfuric acid solution is 1:1.5-2.2; the dosage of citric acid and sodium dodecylbenzene sulfonate is 0.01-0.5wt% and 0.5-2wt% of the titanium-containing blast furnace slag, respectively; and the dosage ratio of the acid hydrolysis slag to deionized water is 1:1-2.

[0014] Preferably, in step (3), the sealed reaction conditions are hydrothermal reaction at 110-160° C. and 0.2-1 MPa for 1-12 h; and the mass ratio of the heterosulfate-containing titanyl solution to the polysuccinimide derivative is 100:0.1-3.

[0015] Preferably, in step (4), the concentration of the NaOH solution is 0.5-5wt%, and the pH is adjusted to 10-14; the stirring conditions at room temperature are stirring at 400-800 r / min for 30-120 min, the drying conditions are drying at 100-110° C. for 1-3 h; and the calcination conditions are calcining in a muffle furnace at 500-1000° C. for 2-5 h.

[0016] Specifically, the structural formula of the polysuccinimide derivative is as follows:

[0017]

[0018] Preferably, the preparation method of the polysuccinimide derivative comprises the following steps:

[0019] a. Dissolve polysuccinimide in DMSO to obtain a PSI solution; dissolve dopamine hydrochloride in DMSO, then add triethylamine, and ultrasonically oscillate to obtain a dopamine solution; add the dopamine solution to the PSI solution, and reflux under a nitrogen atmosphere to obtain a PSI-DA intermediate reaction solution;

[0020] Preferably, in step a, the dosage ratio of PSI, dopamine hydrochloride and triethylamine is 40 mmol: 10-15 mmol: 8-16 mL; the ultrasonic oscillation time is 10-30 min; and the reflux reaction conditions are reflux reaction at 50-70° C. for 18-30 h.

[0021] b. Dissolve glutamic acid in DMSO, then add triethylamine, and perform ultrasonic oscillation to obtain a glutamic acid solution; add the glutamic acid solution to the reaction solution obtained in step (1), stir the reaction under a nitrogen atmosphere, adjust the pH with an aqueous sodium hydroxide solution, precipitate the product with acetone, filter, wash with acetone, and dry to obtain the polysuccinimide derivative.

[0022] Preferably, in step b, the ratio of glutamic acid to triethylamine is 30 mmol:10-20 mL; the stirring reaction conditions are stirring the reaction at 50-70° C. for 12-20 h, and after the reaction is completed, the pH is adjusted to 7-8.

[0023] Preferably, the molar ratio of polysuccinimide, dopamine hydrochloride and glutamic acid is 40:10-15:30-25.

[0024] The reaction consists of two main steps, first the reaction of polysuccinimide (PSI) with dopamine (DA), and then the reaction of the PSI-DA intermediate with glutamic acid. In the first step, triethylamine acts as a strong base to neutralize dopamine hydrochloride and release free dopamine. The primary amine group (-NH 2 ) followed by nucleophilic addition to the imide ring of PSI. This process involves the attack of the nitrogen atom of the amino group on the carbonyl carbon of the imide ring to form a tetrahedral intermediate, which then collapses, leading to the opening of the imide ring and ultimately grafting dopamine onto the polysuccinimide molecular chain.

[0025] In the second step, the α-amino group of glutamic acid undergoes a similar nucleophilic addition reaction to the remaining PSI imide ring. This process is similar to the first step, and also includes the amino group attacking the carbonyl carbon of the imide ring to form a tetrahedral intermediate, the intermediate collapses, the imide ring opens, and glutamic acid is grafted onto the polysuccinimide molecule.

[0026] The result of the whole reaction is that part of the imide rings on the PSI main chain are opened by dopamine, and dopamine side chains are introduced, and the remaining imide rings are opened by glutamic acid, and glutamic acid side chains are introduced. The final product is a polymer containing dopamine and glutamic acid side chains, and some unreacted imide rings may remain on the main chain.

[0027] By introducing side chains with specific functions onto the PSI skeleton, an amphiphilic polymer with good dispersion properties was successfully synthesized. It also combined multiple action mechanisms such as electrostatic stabilization, stereo stabilization and chemical adsorption to achieve an efficient and stable dispersion effect.

[0028] The present invention also claims to protect high-purity spherical titanium dioxide prepared by the preparation method.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1) The present invention provides a method for preparing high-purity spherical titanium dioxide, which uses titanium-containing blast furnace slag as raw material, effectively removes impurities through acid hydrolysis, hydrothermal reaction, desulfurization and roasting, and finally obtains a high-purity titanium dioxide product, realizing the resource utilization of industrial waste, improving economic benefits, and having significant technical value and application prospects. In terms of process optimization, the addition of citric acid and sodium dodecylbenzene sulfonate significantly reduces the content of impurity ions and improves the acid hydrolysis efficiency, while the use of polysuccinimide derivative dispersants reduces agglomeration during the hydrolysis of metatitanic acid, which is conducive to the subsequent formation of titanium dioxide with good dispersibility and sphericity.

[0031] 2) The present invention provides a polysuccinimide derivative dispersant, wherein the glutamic acid side chain contains a large number of carboxylic acid groups, which form carboxylates under alkaline conditions, so that the surface of the hydrothermal titanate colloidal particles is negatively charged, resulting in electrostatic repulsion, effectively preventing the particles from approaching and aggregating, and improving the dispersion stability; in addition, the π bond of the dopamine side chain can form a coordination bond with the d empty orbital of the metal atom, so that the dopamine side chain is firmly adsorbed on the surface of the titanate particles, and when the amide group in the dopamine side chain is close to the π bond, a larger π bond system is formed due to the conjugation effect, which significantly enhances the adsorption force of the derivative on the metal atom, thereby firmly anchoring the derivative on the surface of the titanate colloidal particles, preventing the loss of the dispersant, and maintaining a stable and long-lasting dispersion effect; finally, the spatial structure of the polymer main chain and the side chain forms a protective layer on the particle surface, further preventing the particles from aggregating through a steric barrier effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show schematic diagrams of certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 This is a SEM photograph of the high-purity titanium dioxide prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0035] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from raw materials purchased from commercial sources.

[0036] Polysuccinimide with a molecular weight of 5000 was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0037] The titanium-containing blast furnace slag used in the embodiments and comparative examples comes from a domestic factory, and its chemical composition is shown in Table 1:

[0038] Table 1 Main components of titanium-containing blast furnace slag

[0039] composition <![CDATA[TiO 2 ]]> CaO <![CDATA[SiO 2 ]]> MgO <![CDATA[Al 2 THE 3 ]]> MnO <![CDATA[Fe 2 THE 3 ]]> <![CDATA[SO 3 ]]> <![CDATA[K 2 The]]> Content (wt%) 22.47 30.54 25.59 8.72 11.45 0.71 0.94 1.49 0.68

[0040] A method for preparing high-purity spherical titanium dioxide comprises the following steps:

[0041] (1) Dissolve 40 mmol polysuccinimide in 15 mL DMSO to obtain a PSI solution; dissolve 10-15 mmol dopamine hydrochloride in 15 mL DMSO, then add 8-16 mL triethylamine, and ultrasonically oscillate for 10-30 min to obtain a dopamine solution; add the dopamine solution to the PSI solution, reflux under a nitrogen atmosphere at 50-70°C for 18-30 h to obtain a PSI-DA intermediate reaction solution;

[0042] (2) Dissolve 30-25 mmol of glutamic acid in DMSO, then add 10-20 mL of triethylamine, and ultrasonically oscillate for 10-30 min to obtain a glutamic acid solution; add the glutamic acid solution to the intermediate reaction solution, stir and react at 50-70 °C in a nitrogen atmosphere for 12-20 h, adjust the pH to 7-8 with an aqueous sodium hydroxide solution, precipitate the product with acetone, filter, wash with acetone, and dry to obtain a polysuccinimide derivative;

[0043] (3) crushing and grinding the titanium-containing blast furnace slag and passing it through a 200-600 mesh sieve;

[0044] (4) 1 kg of sieved titanium-containing blast furnace slag is mixed with 1.5-2.2 kg of 85-98 wt% sulfuric acid solution, and 0.1-5 g of citric acid and 5-20 g of sodium dodecylbenzene sulfonate are added, and the mixture is reacted at 70-130° C. for 1-6 h to obtain acid hydrolysis slag; 1 kg of the acid hydrolysis slag is added into 1-2 kg of deionized water, stirred and mixed, and filtered to obtain a solution containing impure sulfuric acid titanium oxide;

[0045] (5) Add 1 kg of the titanium dioxide solution containing impurities of sulfuric acid and 1-30 g of a polysuccinimide derivative into a reaction kettle, and perform a sealed hydrothermal reaction at 110-160° C. and 0.2-1 MPa for 1-12 h. Cool and filter the product to obtain a filter cake, wash and dry the filter cake to obtain hydrothermal metatitanic acid.

[0046] (6) Mixing hydrothermal titanic acid with 0.5-5wt% NaOH solution to form a slurry, adjusting the pH to 10-14, stirring at room temperature at 400-800 r / min for 30-120 min, filtering and washing the product, and drying at 100-110° C. for 1-3 h to obtain desulfurized titanic acid; calcining the desulfurized titanic acid in a muffle furnace at 500-1000° C. for 2-5 h, and cooling to obtain the high-purity spherical titanium dioxide.

[0047] The present invention will be further described below through specific embodiments. Example 1

[0048] A method for preparing high-purity spherical titanium dioxide comprises the following steps:

[0049] (1) Dissolve 40 mmol polysuccinimide in 15 mL DMSO to obtain a PSI solution; dissolve 15 mmol dopamine hydrochloride in 15 mL DMSO, then add 12 mL triethylamine, and ultrasonically oscillate for 30 min to obtain a dopamine solution; add the dopamine solution to the PSI solution, reflux at 60 °C under a nitrogen atmosphere for 26 h to obtain a PSI-DA intermediate reaction solution;

[0050] (2) Dissolve 25 mmol of glutamic acid in DMSO, then add 14 mL of triethylamine, and ultrasonically oscillate for 30 min to obtain a glutamic acid solution; add the glutamic acid solution to the intermediate reaction solution, stir and react at 60 °C in a nitrogen atmosphere for 16 h, adjust the pH to 8 with an aqueous sodium hydroxide solution, precipitate the product with acetone, filter, wash with acetone, and dry to obtain a polysuccinimide derivative;

[0051] (3) crushing and grinding the titanium-containing blast furnace slag and passing it through a 500-mesh sieve;

[0052] (4) 1 kg of sieved titanium-containing blast furnace slag was mixed with 2.2 kg of 95 wt% sulfuric acid solution, and 5 g of citric acid and 20 g of sodium dodecylbenzene sulfonate were added, and the mixture was reacted at 130° C. for 1 h to obtain acid hydrolysis slag; 1 kg of the acid hydrolysis slag was added into 2 kg of deionized water, stirred and mixed, and filtered to obtain a solution containing impure sulfuric acid titanium oxide;

[0053] (5) 1 kg of the titanium dioxide solution containing impurities of sulfuric acid and 15 g of a polysuccinimide derivative were added to a reactor, and the reaction was carried out in a sealed manner under 160° C. and 1 MPa for 1 h. The product was cooled and filtered to obtain a filter cake, and the filter cake was washed and dried to obtain hydrothermal metatitanic acid;

[0054] (6) Mix hydrothermal titanic acid with 5 wt% NaOH solution to form a slurry, adjust the pH to 12, stir at room temperature for 120 min at 600 r / min, filter and wash the product, and dry it at 110°C for 1 h to obtain desulfurized titanic acid; calcine the desulfurized titanic acid in a muffle furnace at 800°C for 3 h, and cool it to obtain anatase-type high-purity spherical titanium dioxide with a purity of 99.87% and a D50 of 54 nm.

[0055] Figure 1 This is a SEM photograph of the high-purity spherical titanium dioxide prepared in Example 1. Example 2

[0056] A method for preparing high-purity spherical titanium dioxide comprises the following steps:

[0057] (1) Dissolve 40 mmol polysuccinimide in 15 mL DMSO to obtain a PSI solution; dissolve 13 mmol dopamine hydrochloride in 15 mL DMSO, then add 12 mL triethylamine, and ultrasonically oscillate for 30 min to obtain a dopamine solution; add the dopamine solution to the PSI solution, reflux at 60 ° C under a nitrogen atmosphere for 26 h to obtain a PSI-DA intermediate reaction solution;

[0058] (2) Dissolve 25 mmol of glutamic acid in DMSO, then add 14 mL of triethylamine, and ultrasonically oscillate for 30 min to obtain a glutamic acid solution; add the glutamic acid solution to the intermediate reaction solution, stir and react at 60 °C in a nitrogen atmosphere for 16 h, adjust the pH to 8 with an aqueous sodium hydroxide solution, precipitate the product with acetone, filter, wash with acetone, and dry to obtain a polysuccinimide derivative;

[0059] (3) crushing and grinding the titanium-containing blast furnace slag and passing it through a 500-mesh sieve;

[0060] (4) 1 kg of sieved titanium-containing blast furnace slag was mixed with 1.8 kg of 95 wt% sulfuric acid solution, and 2.5 g of citric acid and 12 g of sodium dodecylbenzene sulfonate were added, and the mixture was reacted at 100° C. for 4 h to obtain acid hydrolysis slag; 1 kg of the acid hydrolysis slag was added into 1.5 kg of deionized water, stirred and mixed, and filtered to obtain a solution containing impure sulfuric acid titanium oxide;

[0061] (5) Add 1 kg of the impurity sulfate-containing titanium dioxide solution and 30 g of the polysuccinimide derivative into a reactor, and perform a sealed hydrothermal reaction at 140° C. and 0.6 MPa for 66 h. The product is cooled and filtered to obtain a filter cake. The filter cake is washed and dried to obtain hydrothermal metatitanic acid.

[0062] (6) Mix hydrothermal titanic acid with 2.5 wt% NaOH solution to form a slurry, adjust the pH to 12, stir at room temperature at 600 r / min for 80 min, filter and wash the product, and dry it at 105°C for 2 h to obtain desulfurized titanic acid; calcine the desulfurized titanic acid in a muffle furnace at 700°C for 4 h, and cool it to obtain anatase-type high-purity spherical titanium dioxide with a purity of 99.95% and a D50 of 63 nm. Example 3

[0063] A method for preparing high-purity spherical titanium dioxide comprises the following steps:

[0064] (1) Dissolve 40 mmol polysuccinimide in 15 mL DMSO to obtain a PSI solution; dissolve 10 mmol dopamine hydrochloride in 15 mL DMSO, then add 12 mL triethylamine, and ultrasonically oscillate for 30 min to obtain a dopamine solution; add the dopamine solution to the PSI solution, reflux at 60 °C under a nitrogen atmosphere for 26 h to obtain a PSI-DA intermediate reaction solution;

[0065] (2) 30 mmol of glutamic acid was dissolved in DMSO, and then 14 mL of triethylamine was added, and ultrasonic oscillation was performed for 30 min to obtain a glutamic acid solution; the glutamic acid solution was added to the intermediate reaction solution, and the reaction was stirred at 60 ° C for 16 h under a nitrogen atmosphere, and the pH was adjusted to 8 with a sodium hydroxide aqueous solution. The product was precipitated with acetone, filtered, washed with acetone, and dried to obtain a polysuccinimide derivative;

[0066] (3) crushing and grinding the titanium-containing blast furnace slag and passing it through a 500-mesh sieve;

[0067] (4) 1 kg of sieved titanium-containing blast furnace slag was mixed with 1.5 kg of 95 wt% sulfuric acid solution, and 0.1 g of citric acid and 5 g of sodium dodecylbenzene sulfonate were added, and the mixture was reacted at 70° C. for 6 h to obtain acid hydrolysis slag; 1 kg of the acid hydrolysis slag was added to 1 kg of deionized water, stirred and mixed, and filtered to obtain a solution containing impure sulfuric acid titanium oxide;

[0068] (5) Add 1 kg of the titanium dioxide solution containing impurities of sulfuric acid and 10 g of the polysuccinimide derivative into a reactor, and conduct a sealed hydrothermal reaction at 110° C. and 0.2 MPa for 12 h. The product is cooled and filtered to obtain a filter cake. The filter cake is washed and dried to obtain hydrothermal metatitanic acid.

[0069] (6) Mix hydrothermal titanic acid with 0.5 wt% NaOH solution to form a slurry, adjust the pH to 12, stir at room temperature for 30 min at 600 r / min, filter and wash the product, and dry it at 100 °C for 3 h to obtain desulfurized titanic acid; calcine the desulfurized titanic acid in a muffle furnace at 900 °C for 2 h, and cool it to obtain rutile high-purity spherical titanium dioxide with a purity of 99.92% and a D50 of 47 nm.

[0070] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing high-purity spherical titanium dioxide, characterized in that: The steps include: (1) crushing, grinding and sieving titanium-containing blast furnace slag; (2) mixing the sieved titanium-containing blast furnace slag with a sulfuric acid solution, adding citric acid and sodium dodecylbenzene sulfonate, heating for reaction, and obtaining an acid hydrolysis slag; adding the acid hydrolysis slag into deionized water, stirring and mixing, and filtering to obtain an impure sulfuric acid-containing titanium oxide solution; (3) adding a titanium dioxide solution containing impurities of sulfuric acid and a polysuccinimide derivative into a reaction kettle, sealing the reaction kettle, cooling the product, filtering the product to obtain a filter cake, washing the filter cake, and drying the filter cake to obtain hydrothermal metatitanic acid; (4) mixing hydrothermal metatitanic acid and NaOH solution to form a slurry, adjusting the pH, stirring at room temperature, filtering, washing, and drying the product to obtain desulfurized metatitanic acid; calcining the desulfurized metatitanic acid, and cooling to obtain the high-purity spherical titanium dioxide; In step (2), the concentration of the sulfuric acid solution is 85-98 wt %; the heating reaction conditions are 70-130° C. for 1-6 h; the dosage ratio of the titanium-containing blast furnace slag to the sulfuric acid solution is 1:1.5-2.2; The dosage of citric acid and sodium dodecylbenzene sulfonate is 0.01~0.5wt% and 0.5~2wt% of the titanium-containing blast furnace slag respectively; the dosage ratio of acid-lysed slag and deionized water is 1:1~2; In step (3), the sealed reaction conditions are 110-160°C, 0.2-1 MPa, hydrothermal reaction for 1-12 hours; the mass ratio of the heterosulfate-containing titanyl solution to the polysuccinimide derivative is 100:0.1-3; In step (4), the concentration of NaOH solution is 0.5-5wt%, and the pH is adjusted to 10-14; the stirring condition at room temperature is 400-800 r / min for 30-120 min, the drying condition is 100-110° C. for 1-3 h; the calcination condition is 500-1000° C. in a muffle furnace for 2-5 h; The preparation method of the polysuccinimide derivative comprises the following steps: a. Dissolve polysuccinimide in DMSO to obtain a PSI solution; dissolve dopamine hydrochloride in DMSO, then add triethylamine, and perform ultrasonic oscillation to obtain a dopamine solution; The dopamine solution was added to the PSI solution, and the mixture was refluxed under a nitrogen atmosphere to obtain a PSI-DA intermediate reaction solution; b. Dissolve glutamic acid in DMSO, then add triethylamine, and perform ultrasonic oscillation to obtain a glutamic acid solution; Adding the glutamic acid solution to the intermediate reaction solution, stirring the reaction under a nitrogen atmosphere, adjusting the pH with an aqueous sodium hydroxide solution, precipitating the product with acetone, filtering, washing with acetone, and drying to obtain the polysuccinimide derivative; In step a, the dosage ratio of PSI, dopamine hydrochloride and triethylamine is 40mmol:10-15mmol:8-16mL; the ultrasonic oscillation time is 10-30min; the reflux reaction conditions are reflux reaction at 50-70°C for 18-30h; In step b, the ratio of glutamic acid to triethylamine is 30 mmol:10-20 mL; the stirring reaction conditions are 50-70° C. for 12-20 h, and after the reaction, the pH is adjusted to 7-8.

2. The preparation method according to claim 1, characterized in that: In step (1), the product is sieved through a 200-600 mesh sieve.

3. The preparation method according to claim 1, characterized in that: The molar ratio of polysuccinimide, dopamine hydrochloride and glutamic acid is 40:10~15:30~25.

4. A high-purity spherical titanium dioxide prepared by the preparation method according to any one of claims 1 to 3.

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