Preparation method of precipitated silicon dioxide for comfortable new energy vehicle tire

Abstract

The application discloses a preparation method of comfortable new energy vehicle tire precipitated silicon dioxide, and the preparation method comprises the following steps: S1, raw material preparation; S2, preparation of a bottom liquid; S3, a nucleation stage, wherein the water glass solution and the sulfuric acid solution are added dropwise into the bottom liquid; S4, a particle growth stage, wherein the water glass solution and the sulfuric acid solution are continuously added dropwise into the bottom liquid; S5, acidification termination and aging, wherein the water glass solution is stopped from being added dropwise, the sulfuric acid solution is continuously added dropwise and stirring and aging are continued; S6, sulfuric acid supplement after aging; S7, post-treatment, wherein the reaction slurry is subjected to pressure filtration, washing and beating to obtain thick slurry; and S8, drying and crushing, wherein the thick slurry is subjected to spray drying and airflow crushing to obtain high-dispersion precipitated silicon dioxide. Through the process design of supplementing sulfuric acid after aging, compared with a traditional process, the application removes residual impurities in the system, avoids possible side reactions caused by in-situ modification of silane, reduces the product agglomeration risk, and improves the product purity and batch stability.

Description

Technical Field

[0001] This invention relates to the field of silica preparation technology, and in particular to a method for preparing precipitated silica for comfort-type new energy vehicle tires. Background Technology

[0002] Precipitated silica, as a key inorganic reinforcing filler, plays an irreplaceable role in tire manufacturing. Its reinforcing efficiency stems from its ability to form a three-dimensional network structure within the rubber matrix, significantly improving tire wear resistance, tear resistance, and mechanical strength. With the urgent global demand for energy conservation and emission reduction, especially the pursuit of longer driving ranges in new energy vehicles, the market demands lower rolling resistance, higher fuel economy, and superior wear resistance in tires. This correspondingly places higher standards on the performance of precipitated silica, the core reinforcing material: it requires not only a high specific surface area and structure to provide excellent reinforcement, but also excellent dispersibility and precisely controlled surface chemistry to minimize energy loss during dynamic deformation of the rubber.

[0003] Traditional precipitated silica production processes typically rely on the neutralization and precipitation reaction of sodium silicate with inorganic acids, controlling reaction conditions to regulate the nucleation, growth, and aggregation of silica particles. Common processes include single-stage precipitation and co-current precipitation. However, while these traditional or conventionally modified processes are simple to operate, they are prone to problems such as sudden pH drops or localized over-acidification, leading to excessively high and unevenly distributed silanol density on the surface of the formed primary silica particles. Excessive hydroxyl density can cause severe irreversible hard agglomeration of particles before and during drying through strong hydrogen bonding, significantly impairing their final dispersibility in the rubber matrix. Furthermore, the acidification process in traditional processes, used to neutralize residual alkali, is often combined with the pH adjustment of the final product, making it difficult to precisely control the reaction endpoint. This can easily lead to incomplete neutralization or over-acidification, resulting in large fluctuations in product impurity content and affecting batch-to-batch performance stability. Therefore, this paper proposes a method for preparing precipitated silica for comfort-type new energy vehicle tires to address the aforementioned problems. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing precipitated silica for comfort-type new energy vehicle tires, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing precipitated silica for comfort-type new energy vehicle tires, the preparation method comprising the following steps:

[0006] S1, Raw material preparation: Prepare water glass solution using solid sodium silicate, filter and set aside; at the same time, prepare sulfuric acid as an acidifying agent. S2, Preparation of the base solution: Water is added to the reaction vessel as the base water, and the temperature is kept constant by heating. The water glass solution is added dropwise to the base water and stirred to mix, so that the pH of the base solution is controlled at 9.5-10.5. S3, nucleation stage: Continue to add the water glass solution and sulfuric acid solution dropwise to the base liquid, keeping the reaction temperature and stirring speed constant, and controlling the pH value of the reaction system to be maintained within the range of 10.0-11.0, until the volume of the reaction system reaches 60% of the total volume of the reactor; S4, the particle growth stage, the reaction temperature is gradually increased, and the water glass solution and sulfuric acid solution are continued to be added dropwise to the bottom liquid until the volume of the reaction system reaches 80% of the total volume of the reactor; S5, Acidification Termination and Aging: When the volume of the reaction system reaches 80% of the total volume of the reactor, stop adding water glass solution and continue adding sulfuric acid solution to adjust the pH of the reaction system to 6.5-7.5. Then, stir and age at 90-100℃. S6. After aging, sulfuric acid is added. After aging, sulfuric acid is added dropwise to the reaction system to adjust the pH of the system to 4.5-6.5. Then, the temperature is maintained and the mixture is stirred to generate a reaction slurry. S7, Post-processing: The reaction slurry is subjected to pressure filtration, washing, and pulping to obtain a concentrated slurry; S8, Drying and pulverizing: The concentrated slurry is spray-dried and air-jet pulverized to obtain precipitated silica.

[0007] Preferably, the solid sodium silicate has a modulus of 3.0-3.5, the water glass solution has a concentration of 20-25 wt%, and the acidifying agent is sulfuric acid with a concentration of 98 wt% or diluted to 20-30 wt%.

[0008] Preferably, the bottom liquid preparation and nucleation stage reactor is heated by steam to control the temperature of the bottom water in the reactor within the range of 80-90°C, and the temperature is kept constant after stabilization.

[0009] Preferably, in the nucleation stage and the particle growth stage, the water glass solution and the sulfuric acid solution are added dropwise in a continuous and parallel manner, and the flow rate of the water glass solution is always greater than that of the sulfuric acid solution.

[0010] Preferably, the flow rate difference between the water glass solution and the sulfuric acid solution is controlled to be 2-3 L / min, and during the dripping process, the feed tubes of both solutions are inserted below the surface of the bottom liquid.

[0011] Preferably, the heating process during the particle growth stage is slow and stable, with the heating rate controlled at 0.5-1℃ / min, and the stirring speed of the reactor is simultaneously adjusted to 90-100r / min.

[0012] Preferably, when the pH of the reaction system is adjusted to the range of 6.5-7.5, the addition of acid is stopped, and the reaction system is aged for 30 minutes. During the aging period, the state of the slurry in the reactor is observed regularly. The slurry is a uniform milky white suspension with no particle sedimentation or flocculent agglomeration.

[0013] Preferably, after aging, 20-30 wt% dilute sulfuric acid is slowly added dropwise while maintaining the reaction temperature and stirring rate constant, and controlling the pH of the system to decrease by ≤0.2 per minute.

[0014] Preferably, after adjusting the pH of the system to 4.5-6.5, the non-reaction temperature of the reactor is maintained at 90-100°C, and the stirring rate of the reactor is 90-100 r / min, and stirring is continued for 10-15 min.

[0015] Preferably, the reaction slurry is filtered and washed using a plate and frame filter press, and the sodium sulfate content in the filter cake is determined by the conductivity of the washing water, so that the sodium sulfate content in the final product is controlled to be less than 2%.

[0016] The technical effects and advantages of this invention are as follows: This invention, through a process design involving the addition of sulfuric acid after aging, removes residual impurities from the system compared to traditional processes. This avoids potential side reactions from in-situ silane modification, reduces the risk of product agglomeration, and improves product purity and batch stability. It effectively reduces internal friction and wear between rubber molecules, decreases rolling resistance between the tire tread and the ground, thereby increasing vehicle range. Simultaneously, it optimizes the tire tread profile design, resulting in a more uniform contact area and more reasonable pressure distribution during tire operation. While ensuring good grip, it reduces localized tire wear, improves ride stability, and meets the requirements for low rolling resistance, high comfort, and long lifespan. It is suitable for new energy vehicles and various application scenarios requiring low hysteresis and highly dispersed reinforcement. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the operational implementation of the preparation method of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0019] Example 1: The present invention provides, as follows Figure 1 The method for preparing precipitated silica for comfort-type new energy vehicle tires, as shown, includes the following steps: S1, Raw material preparation: Prepare water glass solution using solid sodium silicate, filter and set aside; at the same time, prepare sulfuric acid as an acidifying agent. The modulus of solid sodium silicate is 3.0-3.5, the concentration of water glass solution is 20-25 wt%, and the sulfuric acid used as the acidifying agent is 98 wt% or diluted to 20-30 wt% dilute sulfuric acid; It should be noted that, for raw material preparation, solid sodium silicate with a modulus of 3.0-3.5 is selected. The reaction vessel is cleaned, and a measured amount of deionized water is added. Stirring is started, and the stirring speed of the reaction vessel is 100-200 rpm. Crushed solid sodium silicate is added while stirring to prevent clumping and bridging. The mixture is heated to 70-90℃ and stirred to dissolve. The mixture is kept at this temperature and stirred for 1-2 hours until the solution is completely transparent and free of particles. The solution is then cooled to below 50℃, and a sample is taken to test the sodium silicate content. If the concentration is >25wt%, deionized water is added for dilution. If the concentration is <20wt%, solid sodium silicate is added or the solution is concentrated to finally prepare a water glass solution with a concentration of 20-25wt%. The solution is then filtered through a 100-200 mesh to remove insoluble impurities, resulting in a clear water glass solution for later use. 98wt% sulfuric acid is selected as the acidifying agent for later use. 98wt% sulfuric acid can be used directly or diluted to 20-30wt% dilute sulfuric acid and then cooled for later use. S2, Preparation of the base solution: Water is added to the reaction vessel as the base water, and the temperature is kept constant by heating. The water glass solution is added dropwise to the base water and stirred to mix, so that the pH of the base solution is controlled at 9.5-10.5. The temperature of the bottom water in the reactor during the preparation of the bottom liquid and the subsequent nucleation stage is controlled within the range of 80-90℃ by steam heating, and the temperature is kept constant after stabilization. It should be noted that during the preparation of the base solution, industrial water, accounting for 1 / 6 of the total volume of the reactor, is first added as the base water. After the base water is added, the feed valve is closed to prevent heat loss and impurities from entering during subsequent heating. Then, the indirect steam heating system of the reactor is started, and the base water is slowly heated through the jacket to avoid local overheating or violent boiling caused by direct steam impact. The temperature of the base water is stably controlled within the range of 80-90℃, and maintained at a constant temperature after stabilization to provide a stable temperature environment for the subsequent nucleation reaction. Under constant temperature conditions, a pre-prepared and filtered water glass solution is added dropwise to the reactor at a uniform rate using a metering pump. The dropping rate is monitored in real time by an online pH meter and finely adjusted to ensure that the pH value of the base solution is stably controlled within the range of 9.5-10.5. While adding water glass dropwise, start the stirring device and set the stirring speed of the reactor to 80-90 r / min. Under continuous and uniform stirring, ensure that the water glass solution and the bottom water are quickly and evenly mixed, avoiding excessively high local concentrations or uneven pH distribution. This ensures that the bottom liquid system is homogeneous and stable, laying a good foundation for subsequent co-current reactions and crystal nucleation. S3, nucleation stage: Continue to add the water glass solution and sulfuric acid solution dropwise to the base liquid, keeping the reaction temperature and stirring speed constant, and controlling the pH value of the reaction system to be maintained within the range of 10.0-11.0, until the volume of the reaction system reaches 60% of the total volume of the reactor; During the nucleation and particle growth stages, the water glass solution and sulfuric acid solution are added dropwise in a continuous and parallel manner, ensuring that the flow rate of the water glass solution is always greater than that of the sulfuric acid solution. Furthermore, the flow rate difference between the water glass solution and the sulfuric acid solution is controlled to be 2-3 L / min, and during the dripping process, the feed tubes of both solutions are inserted below the surface of the bottom liquid; It should be noted that during the nucleation stage, dual metering pumps are used to deliver water glass solution and sulfuric acid solution separately, achieving continuous and parallel droplet addition of water glass solution and sulfuric acid solution into the reactor. The droplet rates of the two solutions are controlled to ensure that the flow rate of water glass solution is always greater than that of sulfuric acid solution, with the flow rate difference controlled at 2-3 L / min. This avoids drastic fluctuations in the system pH due to flow rate imbalance. During the droplet addition, the feed pipes of both solutions are inserted below the bottom liquid surface, and the feed inlets are close to the stir bar to ensure that the solutions are quickly and evenly stirred as soon as they enter the reactor, preventing the formation of excessively acidic or alkaline areas and eliminating explosive nucleation phenomena. This keeps the system in a weakly alkaline stable range, facilitating the nucleation reaction. During the reaction, maintain the reaction temperature consistently within the range of 80-90℃, and keep the stirring speed of the reactor at 80-90 r / min. Keep the pH value of the reaction system within the range of 10.0-11.0. Monitor the system volume in real time using the reactor level gauge until the system volume reaches 60% of the total reactor volume. Control the reaction time within 40-60 min. If the reaction time is less than 40 min when the specified volume is reached, reduce the dropping rate of both solutions to ensure a complete reaction. If the reaction time is close to 60 min but the volume does not meet the requirements, increase the dropping rate while maintaining the flow rate ratio and pH stability to avoid excessive crystal growth due to excessive reaction time. S4, the particle growth stage, the reaction temperature is gradually increased, and the water glass solution and sulfuric acid solution are continued to be added dropwise to the bottom liquid until the volume of the reaction system reaches 80% of the total volume of the reactor; The temperature rise during the particle growth stage is slow and steady, with the heating rate controlled at 0.5-1℃ / min, and the stirring speed of the reactor is adjusted to 90-100r / min simultaneously. It should be noted that the dual metering pumps used in the nucleation stage continue to be employed during the particle growth stage, delivering water glass solution and sulfuric acid solution separately. Both solutions are continuously and concurrently added to the reactor, maintaining a flow rate of water glass solution greater than that of sulfuric acid solution. The flow rate difference is adjusted to 3-4 L / min to ensure the system remains in a weakly alkaline environment, providing stable reaction conditions for crystal nucleus growth and preventing uneven growth or localized agglomeration due to flow rate imbalance. The reaction temperature is gradually increased from 80-90℃ in the nucleation stage to 90-100℃, with a slow and stable heating process and a heating rate controlled at 0.5-1℃ / min to avoid rapid, explosive growth of crystal nuclei and the formation of large particle agglomerates due to sudden temperature increases. Simultaneously, the stirring speed of the reactor is adjusted from 80-90 r / min in the nucleation stage to 90-100 r / min. To enhance the mixing uniformity of the solution within the reactor, promote full contact between the crystal nuclei and the reactants, ensure consistent crystal growth rates, and effectively prevent crystal nuclei from colliding, agglomerating, or sticking together during growth, the pH of the reaction system should be maintained within the range of 10.0-11.0 until the system volume reaches 80% of the reactor volume. The reaction time should be set at 60-80 minutes. If the reaction time is less than 60 minutes when the specified volume is reached, the dropping rate of both solutions should be reduced, and the reaction time extended to the specified range to ensure sufficient crystal growth and uniform particle size. If the reaction time is close to 80 minutes but the system volume is less than 80% of the reactor volume, the dropping rate can be slightly increased while maintaining a stable flow ratio, pH, and temperature. This prevents the reaction time from exceeding 80 minutes, which could lead to excessive particle growth and densification, affecting the dispersibility of subsequent products. S5, Acidification Termination and Aging: When the volume of the reaction system reaches 80% of the total volume of the reactor, stop adding water glass solution and continue adding sulfuric acid solution to adjust the pH of the reaction system to 6.5-7.5. Then, stir and age at 90-100℃. After adjusting the pH of the reaction system to the range of 6.5-7.5, stop adding acid and age the reaction system for 30 minutes. During the aging period, observe the state of the slurry in the reactor regularly. The slurry should be a uniform milky white suspension with no particle sedimentation or flocculent agglomeration. It should be noted that after the particle growth stage, when the volume of the reaction system reaches 80% of the reactor volume and the reaction time meets 60-80 minutes, Upon receiving the instructions, immediately stop the co-current dripping of the water glass solution, and only continue the dripping of the sulfuric acid solution. Maintain a stable reactor temperature of 90-100℃ throughout the process, and keep the stirring speed at 90-100 r / min to provide a suitable reaction environment for subsequent pH adjustment. After adjusting the pH of the reaction system to the range of 6.5-7.5, stop adding acid and age the reaction system for 30 minutes. During the aging process, observe the state of the slurry in the reactor every 10 minutes. The slurry should be a uniform milky white suspension, without particle sedimentation or flocculent agglomeration. If local turbidity increases or precipitation occurs, immediately check whether the stirring is normal to ensure that the system is mixed evenly. During the aging process, under a weakly alkaline environment with constant temperature and constant stirring, the hydroxyl groups on the surface of the silica particles undergo condensation and rearrangement, the microporous structure inside the particles gradually closes, and the contact interface between particles becomes more stable, thereby effectively eliminating the inherent tendency to agglomerate and further improving the dispersibility and structural regularity of the particles.

[0020] S6. After aging, sulfuric acid is added. After aging, sulfuric acid is added dropwise to the reaction system to adjust the pH of the system to 4.5-6.5. Then, the temperature is maintained and the mixture is stirred to generate a reaction slurry. After aging, slowly add 20-30 wt% dilute sulfuric acid, keeping the reaction temperature and stirring rate constant, and control the pH of the system to decrease by ≤0.2 per minute; After adjusting the pH of the system to 4.5-6.5, maintain the non-reaction temperature of the reactor at 90-100℃ and the stirring rate of the reactor at 90-100 r / min, and continue stirring for 10-15 min. It should be noted that after the aging process is completed, a 20-30 wt% dilute sulfuric acid solution is slowly added dropwise to the reaction system. Throughout the process, the reaction temperature and stirring rate are kept constant to maintain the stability of the particle structure. The rate of pH decrease during the dropwise addition is controlled to not exceed 0.2 / min. Low-speed, uniform acid addition avoids excessive local acidity that could damage the preliminarily formed silica pore structure, preventing excessive particle densification or structural collapse. Continue adding dilute sulfuric acid until the pH of the reaction system is stably adjusted to the range of 4.5-6.5, then stop adding acid. The total duration of the entire secondary acidification process is controlled to 30 minutes to ensure a thorough and mildly controllable reaction. After acid addition, continue stirring for 10-15 minutes without changing the reaction temperature (900-100℃) and stirring speed (90-100 r / min). The specific stirring time can be adjusted flexibly according to the state of the slurry. If local uneven concentration or poor dispersion is observed, the stirring time can be appropriately extended to 15 minutes to ensure complete homogenization of the system. The core function of this step is to fully neutralize the trace amounts of unreacted residual sodium silicate in the system with dilute sulfuric acid, converting sodium ions into easily washable sodium sulfate, thereby ensuring that the residual sodium oxide content in the final product is stably controlled below 0.18%. Simultaneously, under the synergistic effect of mild acidity and continuous stirring, the silanol groups on the surface of silica particles undergo moderate condensation and rearrangement, precisely controlling the surface hydroxyl density to a suitable range of 4-6 hydroxyl groups / nm². This hydroxyl density significantly weakens the aggregation tendency caused by hydrogen bonding between particles, improving the dispersion performance of the filler in rubber, while retaining sufficient active sites. This provides a good interfacial foundation for the subsequent bonding reaction with the silane coupling agent in the tire tread compounding stage, achieving an optimal balance between dispersibility, processing fluidity, and rubber reinforcement effect. This makes the product more suitable for the comprehensive performance requirements of comfort-oriented new energy vehicle tires, which demand low rolling resistance, high grip, and a stable ride. S7, Post-processing: The reaction slurry is subjected to pressure filtration, washing, and pulping to obtain a concentrated slurry; The reaction slurry is filtered and washed using a plate and frame filter press. The sodium sulfate content in the filter cake is determined by the conductivity of the washing water, and the sodium sulfate content in the final product is controlled to be less than 2%. It should be noted that after the acidification reaction, the silica slurry is uniformly fed into a plate and frame filter press for solid-liquid separation. After separation, the filter cake is washed with deionized water in a countercurrent cycle to fully remove residual sodium sulfate and other soluble salts. During the washing process, the conductivity of the washing wastewater is monitored in real time. The conductivity value is used to indirectly determine the degree of sodium sulfate removal from the filter cake. By combining multi-stage countercurrent washing with online monitoring, the sodium sulfate content in the final product is controlled to be less than 2%. Through a secondary acidification process after aging, the silica slurry can be further purified. The aggregated form of silicon particles is more loose and porous, which significantly improves the water permeability and washing mass transfer efficiency of the filter cake. Compared with the traditional process, the washing efficiency is increased by 30%-40%, effectively shortening the washing time and the overall production cycle, and improving the efficiency of continuous industrial production. After washing, the filter cake is added to deionized water for re-pulping. Under the action of high-speed stirring, it is fully dispersed and homogenized. The solid content of the system after pulping is controlled within the range of 20%-25%. Then, the uniformly mixed slurry is directly fed into the pulper for further homogenization and refinement to produce a stable concentrated slurry that meets the requirements of subsequent spray drying. S8, Drying and pulverizing: The concentrated slurry is spray-dried and air-jet pulverized to obtain precipitated silica; It should be noted that the concentrated silica slurry after washing is sent to a spray dryer for drying. The drying process uses clean hot air generated by natural gas combustion as a heat source, which avoids impurity contamination and ensures a stable heat supply. The inlet air temperature of the spray dryer is controlled at 200-240℃ and the outlet air temperature at 80-105℃. Under continuous atomization drying conditions, powdered silica with good flowability is obtained, and the product moisture content is controlled within the range of 5-7wt% to prevent excessive moisture from affecting storage stability or excessive moisture from causing excessive powder agglomeration. The dried powder is then sent to an air jet mill for ultrafine dispersion and classification. The powder is fully dispersed by high-speed air jet impact, eliminating soft agglomerates formed during the drying process. At the same time, the particle size D50 is precisely controlled at 5-15μm, and finally a highly dispersed precipitated silica product with uniform particles, excellent dispersibility, and suitable for use in comfortable new energy vehicle tires is obtained. The results of adding sulfuric acid after aging are shown in Table 1 below. Table 1 Advantages Comparison Table

[0021] As shown in Table 1 above, the highly dispersed precipitated silica for comfort-type new energy vehicle tires prepared by this process (Example 1) has comprehensive performance that meets and significantly surpasses that of silica prepared by aging and TESPT, especially in terms of Na2O residue, tanδ@0℃, and dispersion grade. Specifically, the Na2O residue content in the highly dispersed precipitated silica of Example 1 is less than ≤0.18%, which is much lower than the Na2O residue content in silica prepared by traditional processes. Furthermore, the dispersion grade of the highly dispersed precipitated silica of Example 1 is above 98%, while the dispersion grade of silica prepared by aging and TESPT is 85% to 90%. The dispersion grade of the highly dispersed precipitated silica of Example 1 is higher than that of silica prepared by traditional processes.

[0022] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is 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 precipitated silica for comfort-type new energy vehicle tires, characterized in that, The preparation method includes the following steps: S1, Raw material preparation: Prepare water glass solution using solid sodium silicate, filter and set aside; at the same time, prepare sulfuric acid as an acidifying agent. S2, Preparation of the base solution: Water is added to the reaction vessel as the base water, and the temperature is kept constant by heating. The water glass solution is added dropwise to the base water and stirred to mix, so that the pH of the base solution is controlled at 9.5-10.

5. S3, nucleation stage: Continue to add the water glass solution and sulfuric acid solution dropwise to the base liquid, keeping the reaction temperature and stirring speed constant, and controlling the pH value of the reaction system to be maintained within the range of 10.0-11.0, until the volume of the reaction system reaches 60% of the total volume of the reactor; S4, the particle growth stage, the reaction temperature is gradually increased, and the water glass solution and sulfuric acid solution are continued to be added dropwise to the bottom liquid until the volume of the reaction system reaches 80% of the total volume of the reactor; S5, Acidification Termination and Aging: When the volume of the reaction system reaches 80% of the total volume of the reactor, stop adding water glass solution and continue adding sulfuric acid solution to adjust the pH of the reaction system to 6.5-7.

5. Then, stir and age at 90-100℃. S6. After aging, sulfuric acid is added. After aging, sulfuric acid is added dropwise to the reaction system to adjust the pH of the system to 4.5-6.

5. Then, the temperature is maintained and the mixture is stirred to generate a reaction slurry. S7, Post-processing: The reaction slurry is subjected to pressure filtration, washing, and pulping to obtain a concentrated slurry; S8, Drying and pulverizing: The concentrated slurry is spray-dried and air-jet pulverized to obtain precipitated silica.

2. The method for preparing precipitated silica for comfort-type new energy vehicle tires according to claim 1, characterized in that, The solid sodium silicate has a modulus of 3.0-3.5, the water glass solution has a concentration of 20-25 wt%, and the acidifying agent is sulfuric acid with a concentration of 98 wt% or diluted to 20-30 wt%.

3. The method for preparing precipitated silica for comfort-type new energy vehicle tires according to claim 1, characterized in that, The bottom liquid preparation and nucleation stage reactors are heated by steam to control the temperature of the bottom water in the reactor within the range of 80-90℃, and the temperature is kept constant after stabilization.

4. The method for preparing precipitated silica for comfort-type new energy vehicle tires according to claim 1, characterized in that, During the nucleation and particle growth stages, the water glass solution and sulfuric acid solution are added dropwise in a continuous and parallel manner, ensuring that the flow rate of the water glass solution is always greater than that of the sulfuric acid solution.

5. The method for preparing precipitated silica for comfort-type new energy vehicle tires according to claim 4, characterized in that, The flow rate difference between the water glass solution and the sulfuric acid solution is controlled to be 2-3 L / min. During the dripping process, the feed tubes of both solutions are inserted below the surface of the bottom liquid.

6. The method for preparing precipitated silica for comfort-type new energy vehicle tires according to claim 1, characterized in that, The heating process during the particle growth stage is slow and stable, with the heating rate controlled at 0.5-1℃ / min, and the stirring speed of the reactor is adjusted to 90-100r / min simultaneously.

7. The method for preparing precipitated silica for comfort-type new energy vehicle tires according to claim 1, characterized in that, Once the pH of the reaction system is adjusted to the range of 6.5-7.5, stop adding acid and allow the reaction system to age for 30 minutes. During aging, regularly observe the state of the slurry in the reactor. The slurry should be a uniform milky white suspension with no particle sedimentation or flocculent agglomeration.

8. The method for preparing precipitated silica for comfort-type new energy vehicle tires according to claim 1, characterized in that, After aging, 20-30 wt% dilute sulfuric acid is slowly added dropwise while maintaining the reaction temperature and stirring rate constant, and controlling the pH of the system to decrease by ≤0.2 per minute.

9. The method for preparing precipitated silica for comfort-type new energy vehicle tires according to claim 1, characterized in that, After adjusting the pH of the system to 4.5-6.5, maintain the non-reaction temperature of the reactor at 90-100℃ and the stirring rate of the reactor at 90-100 r / min, and continue stirring for 10-15 min.

10. The method for preparing precipitated silica for comfort-type new energy vehicle tires according to claim 1, characterized in that, The reaction slurry is filtered and washed using a plate and frame filter press, and the sodium sulfate content in the filter cake is determined by the conductivity of the washing water, so that the sodium sulfate content in the final product is controlled to be less than 2%.

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