Production technology of ultra-high specific surface area and high dispersibility silica for special tires

Abstract

The application provides a production technology of ultra-high specific surface area high-dispersibility silicon dioxide for special tires, and belongs to the technical field of silicon dioxide production; the production method comprises the steps of liquid water glass pretreatment, initial mixing, first-time acid adding, simultaneous acid and alkali adding, and second-time acid adding; the liquid water glass pretreatment step is as follows: liquid water glass is added into deionized water, uniformly stirred, then amino-trimethylene phosphonic acid solution is added, stirring is carried out at 40-50 DEG C for 25-40 min, after the stirring is completed, 1-ethyl-3-methyl imidazole acetate is added, heat preservation stirring is carried out for 18-25 min, then microwave treatment is carried out, and pretreated liquid water glass is obtained; the prepared silicon dioxide has good dispersibility and high specific surface area, and can effectively improve the strength performance and stability of the special tire when used in the special tire.

Description

Technical Field

[0001] This invention belongs to the field of silica production technology, specifically relating to a production technology for ultra-high specific surface area and highly dispersible silica for special tires. Background Technology

[0002] Silica, as an inorganic non-metallic material, has a large number of hydroxyl groups on its surface, giving it good reactivity and adsorption properties. It also has high chemical stability, good high temperature resistance and corrosion resistance, and has wide application value in the fields of special tires, coatings, catalyst carriers, toothpaste, food additives and pharmaceuticals.

[0003] Silica can replace carbon black as a green rubber reinforcing agent in specialty tires. It can enhance the friction between the tire and the ground, improving its anti-skid performance. Silica with an ultra-high specific surface area can form a dense reinforcing network, reducing internal friction between rubber molecular chains and lowering rolling resistance. Furthermore, highly dispersible silica can be uniformly dispersed in the rubber matrix, avoiding cracking caused by localized stress and effectively extending service life. Therefore, silica has significant research value in the tire industry.

[0004] The specific surface area of ​​silica reflects the size of its basic particles and is a major indicator affecting its application performance. A low specific surface area will affect the wear resistance and tear strength of tires, shortening tire life. The smaller the particles and the larger the specific surface area, the better the reinforcing effect in rubber. However, when the specific surface area is too large, the cohesive force between particles is enhanced, making it difficult to disperse in the rubber compound. This results in high viscosity, high heat generation, and easy scorching of the rubber compound during processing. On the other hand, it will adsorb more accelerators, accelerate the decomposition of accelerators, and thus delay the vulcanization time, ultimately limiting its application in special tires.

[0005] CN113905985A discloses a precipitated silica for green tires and its preparation method. Specifically, ammonia is added to a mixed solution of fluorosilicic acid and sodium silicate to obtain a first slurry; the first slurry is mixed with an ammonium salt solution to obtain a second slurry; the second slurry is mixed with ammonia and processed. During the processing, solid-liquid separation is performed every time the pH value decreases by 0.2-0.5, and then the pH value of the filtrate is adjusted to a predetermined pH value and the processing continues until no precipitate is formed. The solid phase obtained from the solid-liquid separation is mixed to obtain the precipitated silica for green tires.

[0006] The silicon dioxide produced by this patent has a specific surface area of ​​210-230 m². 2 The tensile strength of the vulcanizate obtained by [reason] g was 44.2-52.6 MPa, and the abrasion resistance was 0.18-0.3 cm. 3 / 1.6km, with a tear strength of 150-180kN / m.

[0007] It is evident that the silica produced by the aforementioned patent has a low specific surface area, only 210-230 m². 2 / g, the vulcanized rubber produced by it has poor abrasion resistance.

[0008] Furthermore, the specific surface area of ​​silica for special tires produced by existing processes is unlikely to exceed 300 m². 2 / g, and its high specific surface area leads to decreased dispersibility, which in turn affects the overall performance of special tires and shortens their service life. Summary of the Invention

[0009] To address the technical problems existing in the prior art, this invention provides a production technology for ultra-high specific surface area and highly dispersible silica for special tires. The silica has a specific surface area of ​​300 m² / g while possessing excellent dispersibility and stability. When used in special tires, it can effectively enhance the wear resistance and strength performance of the tires.

[0010] To address the aforementioned technical problems, the present invention adopts the following technical solution: A production technology for ultra-high specific surface area and highly dispersible silica for special tires, the specific operation of which is as follows: 1. Liquid water glass pretreatment Liquid water glass was added to deionized water and stirred until homogeneous. Then, aminotrimethylenephosphonic acid solution was added, and the temperature was raised to 40-50℃. The mixture was stirred at 70-100 rpm for 25-40 minutes. After stirring, 1-ethyl-3-methylimidazolium acetate was added, and the mixture was kept warm and stirred for 18-25 minutes. Then, microwave treatment was performed with a microwave power of 540-560W for 14-17 minutes. After microwave treatment, pretreated liquid water glass was obtained. The concentration of the liquid water glass is 1.2-1.3 mol / L, and the modulus is 3.2-3.3; The mass ratio of the liquid water glass, deionized water, aminotrimethylenephosphonic acid solution, and 1-ethyl-3-methylimidazolium acetate is 110-130:70:13-18:0.45-0.50. The aminotrimethylenephosphonic acid solution is prepared by mixing aminotrimethylenephosphonic acid with deionized water, wherein the mass ratio of aminotrimethylenephosphonic acid to deionized water is 0.4-0.7:20.

[0011] 2. Initial mixing Add deionized water at 40-50℃ and pretreated liquid water glass to the stirred reactor, then control the stirring speed at 70-90 r / min, increase the temperature to 75-85℃ at a rate of 0.8-1.2℃ / min, add dispersant, stir evenly, and obtain a mixture. The concentration of the liquid water glass is 1.2-1.3 mol / L, and the modulus is 3.2-3.3; The mass ratio of the deionized water, pretreated liquid water glass, and dispersant is 56-60:34-38:0.72-0.75; The dispersant is a mixture of sodium polystyrene sulfonate and sodium hexametaphosphate, wherein the mass ratio of sodium polystyrene sulfonate to sodium hexametaphosphate is 1:0.8-1.2.

[0012] 3. Add acid at once Add sulfuric acid to the mixture at a flow rate of 40-43 kg / h for 20-25 min. Then add rare earth solution and heat the mixture to 88-95℃ at a rate of 0.8-1.2℃ / min. Stop adding sulfuric acid when the pH value is 8.5-9.0 to obtain an acid-added solution. The sulfuric acid has a mass concentration of 8-10%; The rare earth solution is a mixture of deionized water, zirconium nitrate, and cerium nitrate, wherein the mass ratio of the deionized water, zirconium nitrate, and cerium nitrate is 45:5.0-5.5:2.0-2.5. The mass ratio of the rare earth liquid to the mixed liquid is 1:115-125.

[0013] 4. Add acid and alkali simultaneously Sulfuric acid and liquid water glass are added to the acid addition solution simultaneously. The flow rate of liquid water glass is controlled at 18-19 kg / h, the temperature is maintained at 88-95℃, the addition time is 25-35 min, and the pH value is maintained at 8.5-9.0 to obtain an acid-base mixture. The sulfuric acid has a mass concentration of 8-10%; The concentration of the liquid water glass is 1.2-1.3 mol / L, and the modulus is 3.2-3.3.

[0014] 5. Secondary acid addition Sulfuric acid is added to the acid-base mixture, with the flow rate controlled at 20-22 kg / h and the temperature controlled at 88-95℃. When the pH reaches 4.2-4.8, the addition of sulfuric acid is stopped. After aging for 22-25 min, the temperature is lowered to 40-48℃. After pressure filtration, pulping, and drying, the temperature is increased to 345-355℃ at a rate of 2.5-3.5℃ / min and kept at this temperature for 2.3-2.8 h. After natural cooling to room temperature, ultra-high specific surface area highly dispersible silica is obtained.

[0015] This invention pretreats liquid water glass. Aminotrimethylenephosphonic acid can chelate metal ions in the water glass, thereby promoting a smoother, more uniform, and controllable reaction process. 1-Ethyl-3-methylimidazolium acetate can adsorb onto the silicate surface, preventing particle aggregation through steric hindrance and contributing to the formation of a more porous initial structure. Combined with microwave treatment, high-frequency electromagnetic waves cause rapid molecular vibration within the system, generating a uniform internal heating effect, promoting thorough mixing of water glass, aminotrimethylenephosphonic acid, and 1-ethyl-3-methylimidazolium acetate, and activating the reaction system. In the initial mixing step, a dispersant is used to provide a stable dispersion environment for subsequent polymerization. In the first acid addition step, Zr in the rare earth solution... 4+ and Ce 3+ It can be adsorbed on the surface of primary silicon particles, and the positive charge of rare earth ions forms an electrostatic attraction with the negative charge of silicon particles, which enhances the mechanical strength of the silicon dioxide network skeleton, preventing the collapse and shrinkage of the pore structure during subsequent aging and shrinkage, thus enhancing the stability of silicon dioxide, increasing the specific surface area, and improving the dispersion performance of the product.

[0016] When the silica prepared by this invention is used in special tires, it has a large contact area with rubber, good bonding, good dispersibility, and good compatibility in the rubber system. Furthermore, it can uniformly transfer external stress to the rubber matrix through stress dispersion, reducing local stress concentration, thereby enhancing the strength performance of the tire and ensuring its stability.

[0017] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. The silicon dioxide prepared by this invention has a specific surface area of ​​213-322 m². 2 / g, loss on heating at 115℃ is 1.54-1.68%, loss on ignition at 1100℃ is 3.12-3.34%, oil absorption value is 238-245 10 -5 m 3 / kg; 2. The silica obtained by this invention was used to prepare tire rubber sheets, and the Akron wear of the tire rubber sheets was measured to be 0.032-0.045 cm. 3 / 1.61km, 300% constant tensile stress is 13.2-13.8MPa, tensile strength is 24.7-25.6MPa, and elongation at break is 475-486%; After the tire rubber sheet was left to stand at 90℃ for 168 hours, the 300% constant elongation stress of the tire rubber sheet was measured again to be 12.4-13.1 MPa, the tensile strength was 23.0-24.2 MPa, and the elongation at break was 450-468%. Detailed Implementation

[0018] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention are now described.

[0019] Example 1 1. Liquid water glass pretreatment 110g of liquid water glass was added to 70g of deionized water and stirred evenly. Then, 13g of aminotrimethylenephosphonic acid solution was added, the temperature was raised to 40℃, and the mixture was stirred at 70rpm for 40min. After stirring, 0.45g of 1-ethyl-3-methylimidazolium acetate was added, and the mixture was kept warm and stirred for 25min. Then, it was microwaved at a power of 540W for 14min. After the microwave treatment, pretreated liquid water glass was obtained. The concentration of the liquid water glass is 1.2 mol / L, and the modulus is 3.2; The aminotrimethylenephosphonic acid solution is prepared by mixing aminotrimethylenephosphonic acid with deionized water, wherein the mass ratio of aminotrimethylenephosphonic acid to deionized water is 0.4:20.

[0020] 2. Initial mixing Add 56 kg of deionized water at 40°C and 34 kg of pretreated liquid water glass to a stirred reactor. Then, control the stirring speed at 70 r / min, increase the temperature to 75°C at a rate of 0.8°C / min, add 0.72 kg of dispersant, and stir evenly to obtain a mixture. The concentration of the liquid water glass is 1.2 mol / L, and the modulus is 3.2; The dispersant is a mixture of sodium polystyrene sulfonate and sodium hexametaphosphate, wherein the mass ratio of sodium polystyrene sulfonate to sodium hexametaphosphate is 1:0.8.

[0021] 3. Add acid at once Sulfuric acid was added to the mixture at a flow rate of 40 kg / h for 20 min. Rare earth solution was then added, and the temperature was increased to 88°C at a rate of 0.8°C / min. When the pH value reached 8.5, the addition of sulfuric acid was stopped, resulting in an acid-added solution. The sulfuric acid has a mass concentration of 8%; The rare earth solution is a mixture of deionized water, zirconium nitrate, and cerium nitrate, wherein the mass ratio of the deionized water, zirconium nitrate, and cerium nitrate is 45:5.0:2.5. The mass ratio of the rare earth liquid to the mixed liquid is 1:115.

[0022] 4. Add acid and alkali simultaneously Sulfuric acid and liquid water glass were added to the acid addition solution at the same time. The flow rate of liquid water glass was controlled at 18 kg / h, the temperature was maintained at 88℃, the addition time was 25 min, and the pH value was maintained at 8.5 to obtain an acid-base mixture. The sulfuric acid has a mass concentration of 8%; The concentration of the liquid water glass is 1.2 mol / L, and the modulus is 3.2.

[0023] 5. Secondary acid addition Sulfuric acid was added to the acid-base mixture, with the flow rate controlled at 20 kg / h and the temperature controlled at 88℃. When the pH reached 4.2, the addition of sulfuric acid was stopped. After aging for 22 min, the temperature was lowered to 40℃. After pressure filtration, pulping, and drying, the temperature was increased to 345℃ at a rate of 2.5℃ / min and kept at that temperature for 2.8 h. After natural cooling to room temperature, ultra-high specific surface area highly dispersible silica was obtained.

[0024] Example 2 1. Liquid water glass pretreatment 130g of liquid water glass was added to 70g of deionized water and stirred evenly. Then, 18g of aminotrimethylenephosphonic acid solution was added, the temperature was raised to 50℃, and the mixture was stirred at 100rpm for 25min. After stirring, 0.50g of 1-ethyl-3-methylimidazolium acetate was added, and the mixture was kept warm and stirred for 18min. Then, it was microwaved at a power of 560W for 17min. After the microwave treatment, pretreated liquid water glass was obtained. The concentration of the liquid water glass is 1.3 mol / L, and the modulus is 3.3; The aminotrimethylenephosphonic acid solution is prepared by mixing aminotrimethylenephosphonic acid with deionized water, wherein the mass ratio of aminotrimethylenephosphonic acid to deionized water is 0.7:20.

[0025] 2. Initial mixing Add 60 kg of deionized water at 50°C and 38 kg of pretreated liquid water glass to a stirred reactor. Then, control the stirring speed at 90 r / min and increase the temperature to 85°C at a rate of 1.2°C / min. Add 0.75 kg of dispersant and stir until homogeneous to obtain a mixture. The concentration of the liquid water glass is 1.3 mol / L, and the modulus is 3.3; The dispersant is a mixture of sodium polystyrene sulfonate and sodium hexametaphosphate, wherein the mass ratio of sodium polystyrene sulfonate to sodium hexametaphosphate is 1:1.2.

[0026] 3. Add acid at once Sulfuric acid was added to the mixture at a flow rate of 43 kg / h for 25 min. Rare earth solution was then added, and the temperature was increased to 95℃ at a rate of 1.2℃ / min. When the pH value reached 9.0, the addition of sulfuric acid was stopped, resulting in an acid-added solution. The sulfuric acid has a mass concentration of 10%. The rare earth solution is a mixture of deionized water, zirconium nitrate, and cerium nitrate, wherein the mass ratio of the deionized water, zirconium nitrate, and cerium nitrate is 45:5.5:2.0. The mass ratio of the rare earth liquid to the mixed liquid is 1:125.

[0027] 4. Add acid and alkali simultaneously Sulfuric acid and liquid water glass were added to the acid addition solution at the same time. The flow rate of liquid water glass was controlled at 19 kg / h, the temperature was maintained at 95℃, the addition time was 35 min, and the pH value was maintained at 9.0 to obtain an acid-base mixture. The sulfuric acid has a mass concentration of 10%. The concentration of the liquid water glass is 1.3 mol / L, and the modulus is 3.3.

[0028] 5. Secondary acid addition Sulfuric acid was added to the acid-base mixture, with the flow rate controlled at 22 kg / h and the temperature at 95℃. When the pH reached 4.8, the addition of sulfuric acid was stopped. After aging for 25 min, the temperature was lowered to 48℃. After pressure filtration, pulping, and drying, the temperature was increased to 355℃ at a rate of 3.5℃ / min and held for 2.3 h. After natural cooling to room temperature, ultra-high specific surface area highly dispersible silica was obtained.

[0029] Example 3 1. Liquid water glass pretreatment 120g of liquid water glass was added to 70g of deionized water and stirred evenly. Then, 15g of aminotrimethylenephosphonic acid solution was added, the temperature was raised to 45℃, and the mixture was stirred at 80rpm for 30min. After stirring, 0.47g of 1-ethyl-3-methylimidazolium acetate was added, and the mixture was kept warm and stirred for 20min. Then, it was microwaved at a power of 550W for 15min. After the microwave treatment, pretreated liquid water glass was obtained. The concentration of the liquid water glass is 1.3 mol / L, and the modulus is 3.3; The aminotrimethylenephosphonic acid solution is prepared by mixing aminotrimethylenephosphonic acid with deionized water, wherein the mass ratio of aminotrimethylenephosphonic acid to deionized water is 0.5:20.

[0030] 2. Initial mixing Add 57 kg of deionized water at 45°C and 36 kg of pretreated liquid water glass to a stirred reactor. Then, control the stirring speed at 80 r / min, increase the temperature to 80°C at a rate of 1°C / min, add 0.74 kg of dispersant, and stir evenly to obtain a mixture. The concentration of the liquid water glass is 1.3 mol / L, and the modulus is 3.3; The dispersant is a mixture of sodium polystyrene sulfonate and sodium hexametaphosphate, wherein the mass ratio of sodium polystyrene sulfonate to sodium hexametaphosphate is 1:1.

[0031] 3. Add acid at once Sulfuric acid was added to the mixture at a flow rate of 42 kg / h for 23 min. Rare earth solution was then added, and the temperature was increased to 90°C at a rate of 1°C / min. When the pH value reached 8.8, the addition of sulfuric acid was stopped, resulting in an acid-added solution. The sulfuric acid has a mass concentration of 9%; The rare earth solution is a mixture of deionized water, zirconium nitrate, and cerium nitrate, wherein the mass ratio of the deionized water, zirconium nitrate, and cerium nitrate is 45:5.2:2.3. The mass ratio of the rare earth liquid to the mixed liquid is 1:120.

[0032] 4. Add acid and alkali simultaneously Sulfuric acid and liquid water glass were added to the acid addition solution at the same time. The flow rate of liquid water glass was controlled at 18.5 kg / h, the temperature was maintained at 90℃, the addition time was 30 min, and the pH value was maintained at 8.8 to obtain an acid-base mixture. The sulfuric acid has a mass concentration of 9%; The concentration of the liquid water glass is 1.3 mol / L, and the modulus is 3.3.

[0033] 5. Secondary acid addition Sulfuric acid was added to the acid-base mixture, with the flow rate controlled at 21 kg / h and the temperature controlled at 90℃. When the pH reached 4.6, the addition of sulfuric acid was stopped. After aging for 23 min, the temperature was lowered to 45℃. After pressure filtration, pulping, and drying, the temperature was increased to 350℃ at a rate of 3.0℃ / min and kept at that temperature for 2.5 h. After natural cooling to room temperature, ultra-high specific surface area highly dispersible silica was obtained.

[0034] Comparative Example 1 Based on Example 3, the following changes were made: The liquid water glass pretreatment step is omitted; in the initial mixing step, the pretreated liquid water glass is replaced by an equal amount of untreated liquid water glass, the concentration of which is 1.3 mol / L and the modulus is 3.3. The rest of the operations are exactly the same.

[0035] Comparative Example 2 Based on Example 3, the following changes were made: In the initial mixing step, sodium polystyrene sulfonate in the dispersant is replaced with an equal amount of sodium hexametaphosphate; In one acid addition step, the operation of "adding rare earth solution" is omitted; The rest of the operations are exactly the same.

[0036] 1. Basic performance The performance of the ultra-high specific surface area and highly dispersible silica prepared in Examples 1-3 and Comparative Examples 1-2 was tested, and the details are as follows:

[0037] 2. Application performance The ultra-high specific surface area highly dispersed silica obtained in Examples 1-3 and Comparative Examples 1-2 were respectively used to prepare tire rubber sheets. The formulations of the tire rubber sheets are as follows:

[0038] The preparation method of tire rubber sheets is as follows: According to the formula ratio in the table above, SSBR 2564T and BR9000 are added to a mixing mill. The rotor speed of the mixing mill is controlled at 50 rpm, the mixing temperature at 145℃, the mixing pressure at 0.5 MPa, and the mixing time at 200 s. After mixing, the rubber is discharged and naturally cooled to room temperature to obtain a primary compound. The primary compound, ultra-high specific surface area highly dispersible silica, Si69, environmentally friendly aromatic oil TDAE, zinc oxide, stearic acid, rubber protective wax, and antioxidant 6PPD are added to the mixing mill, and the mixing time is controlled at 50 rpm, 145℃, 0.5 MPa, and 200 s. The mill rotor speed is 50 rpm, the mixing temperature is 125℃, the mixing pressure is 0.35 MPa, and the mixing time is 160 s. After mixing, the rubber is discharged and naturally cooled to room temperature to obtain the second-stage compound. The second-stage compound, sulfur, accelerator CZ, and accelerator DPG are added to the internal mixer. The internal mixer rotor speed is controlled at 50 rpm, the mixing temperature is 105℃, the mixing pressure is 0.2 MPa, and the mixing time is 100 s. After mixing, tire rubber sheets are obtained.

[0039] The tire rubber sheets obtained in Examples 1-3 and Comparative Examples 1-2 were used as test samples for comprehensive performance testing, as detailed below:

[0040] As can be seen from the table above, Comparative Example 1 omitted the pretreatment of liquid water glass. Water glass has poor dispersibility of silicon-oxygen tetrahedra and is prone to forming large aggregates locally. In the initial mixing and acid addition steps, the reaction rate of the aggregates is uneven, resulting in uneven particle size of silica and poor dispersibility. The silica obtained during the reaction process has high density, resulting in a low specific surface area of ​​the product. When used in special tires, it has poor compatibility and poor bonding in the rubber matrix, ultimately leading to poor homogeneity, low strength, and poor stability of the tire. Comparative Example 2 used only sodium hexametaphosphate as a dispersant, resulting in poor dispersibility of the mixture and high degree of aggregation of silicon oxide ions during the reaction process, thereby reducing the porosity and specific surface area of ​​the product. Furthermore, the rare earth liquid was omitted in the first acid addition step, causing disordered growth of silicon oxide particles during the reaction. The resulting product had uneven particle size, low specific surface area, and poor dispersibility, which affected its application in special tires and the overall performance of the special tires.

[0041] Unless otherwise specified, all proportions mentioned in this invention are mass proportions, and all percentages are mass percentages.

[0042] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing ultra-high specific surface area highly dispersible silica for special tires, characterized in that, This includes steps such as liquid water glass pretreatment, initial mixing, primary acid addition, simultaneous acid and alkali addition, and secondary acid addition. The liquid water glass pretreatment step is as follows: add liquid water glass to deionized water, stir evenly, add aminotrimethylenephosphonic acid solution, stir at 40-50℃ for 25-40 min, after stirring, add 1-ethyl-3-methylimidazolium acetate, keep warm and stir for 18-25 min, and then perform microwave treatment to obtain pretreated liquid water glass. In the liquid water glass pretreatment step, the concentration of the liquid water glass is 1.2-1.3 mol / L, and the modulus is 3.2-3.3; The mass ratio of the liquid water glass, deionized water, aminotrimethylenephosphonic acid solution, and 1-ethyl-3-methylimidazolium acetate is 110-130:70:13-18:0.45-0.

50. The aminotrimethylenephosphonic acid solution is prepared by mixing aminotrimethylenephosphonic acid with deionized water, wherein the mass ratio of aminotrimethylenephosphonic acid to deionized water is 0.4-0.7:

20. The initial mixing step involves adding deionized water at 40-50°C and pretreated liquid water glass to a stirred reactor, then controlling the stirring speed at 70-90 r / min, increasing the temperature to 75-85°C at a rate of 0.8-1.2°C / min, adding a dispersant, and stirring until homogeneous to obtain a mixed liquid. The concentration of the liquid water glass is 1.2-1.3 mol / L, and the modulus is 3.2-3.3; The mass ratio of the deionized water, pretreated liquid water glass, and dispersant is 56-60:34-38:0.72-0.75; The dispersant is a mixture of sodium polystyrene sulfonate and sodium hexametaphosphate, with a mass ratio of sodium polystyrene sulfonate to sodium hexametaphosphate of 1:0.8-1.2; The first acid addition step is as follows: sulfuric acid is added to the mixture at a flow rate of 40-43 kg / h. When the sulfuric acid is added for 20-25 minutes, rare earth solution is added, and the temperature is raised to 88-95℃ at a rate of 0.8-1.2℃ / min. When the pH value is 8.5-9.0, the addition of sulfuric acid is stopped to obtain the acid-added solution. The sulfuric acid has a mass concentration of 8-10%; In the rare earth solution, the mass ratio of deionized water, zirconium nitrate, and cerium nitrate is 45:5.0-5.5:2.0-2.5; The mass ratio of the rare earth liquid to the mixed liquid is 1:115-125; The step of simultaneously adding acid and alkali is as follows: sulfuric acid and liquid water glass are added to the acid addition solution at the same time, the flow rate of liquid water glass is controlled at 18-19 kg / h, the temperature is maintained at 88-95℃, the addition time is 25-35 min, and the pH value is maintained at 8.5-9.0 to obtain an acid-alkali mixture. The sulfuric acid has a mass concentration of 8-10%; The concentration of the liquid water glass is 1.2-1.3 mol / L, and the modulus is 3.2-3.3; The secondary acid addition step involves adding sulfuric acid to the acid-base mixture, controlling the sulfuric acid flow rate at 20-22 kg / h and the temperature at 88-95℃. When the pH reaches 4.2-4.8, the addition of sulfuric acid is stopped. After aging for 22-25 minutes, the temperature is lowered to 40-48℃. After pressure filtration, pulping, and drying, the temperature is increased to 345-355℃ at a rate of 2.5-3.5℃ / min and held at that temperature for 2.3-2.8 hours. After natural cooling to room temperature, ultra-high specific surface area highly dispersible silica is obtained.

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