Preparation method of precipitated silicon dioxide for heavy truck

Abstract

The invention discloses a method for preparing precipitated silicon dioxide for a heavy truck, and belongs to the technical field of silicon dioxide preparation, the method comprises the following steps: S1, selecting solid sodium silicate with modulus of 3.3-3.5, preparing a sodium silicate solution with concentration of 30-35 wt%, in the preparation process, firstly putting the solid sodium silicate into a crusher for crushing, and then putting the crushed solid sodium silicate into a stirrer for stirring; then adding the crushed solid sodium silicate into deionized water, stirring, and heating in the stirring process; the specific surface area of the target product is high and reaches 200-240 m < 2 > / g, the dispersion grade reaches 9.8 or above, meanwhile, the mechanical strength is remarkably improved, the tensile strength reaches 25 MPa or above, the 300% stress at definite elongation reaches 7.0 MPa or above, a two-step seed crystal method preparation process is adopted, the regularity of the microstructure of the product is higher, and the product has the higher surface area and higher mechanical performance.

Description

Technical Field

[0001] The invention belongs to the technical field of silicon dioxide preparation, and in particular relates to a method for preparing silicon dioxide for heavy trucks using a precipitation method. Background Art

[0002] With the development of the road transport industry, rising oil prices, and intensified nationwide load management efforts, logistics companies are increasingly focused on the efficiency and economy of road transport. This has driven the rapid development of heavy-duty trucks towards higher-end and higher-powered models. Since 2015, the global heavy-duty truck industry has generally shown steady growth. According to statistics from the International Organization of Motor Vehicle Manufacturers (OICA), global heavy-duty truck production is expected to increase from 3.3975 million units to 3.7744 million units from 2015 to 2023, with a compound annual growth rate of 1.32%. The Chinese truck market is generally developing steadily and positively. According to data released by the China Association of Automobile Manufacturers, the number of medium and heavy-duty trucks in my country will increase from 751,000 units in 2015 to 1.018 million units in 2023, with a compound annual growth rate of 3.88%. With the continued recovery of the global economy, road transport demand in various countries is expected to steadily recover. The gradual introduction of new energy vehicle models and the large-scale infrastructure development in emerging economies around the world will significantly drive demand for truck capacity, and the truck tire market is expected to maintain steady growth.

[0003] Due to the unique operating environment, heavy-duty trucks place high demands on load-bearing capacity, braking performance, and driving comfort. Tires, as key components for their normal operation, play a vital role. Consequently, high performance requirements are placed on heavy-duty truck tires, requiring them to possess superior strength, wear resistance, and grip. To address this, we propose a method for preparing precipitated silica for heavy-duty trucks. Summary of the Invention

[0004] The present invention provides a method for preparing precipitated silica for heavy trucks to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing precipitated silica for heavy trucks, comprising the following steps:

[0006] S1. Select solid sodium silicate with a modulus of 3.3 to 3.5 and prepare a sodium silicate solution with a concentration of 30 wt% to 35 wt%. During the preparation process, first put the solid sodium silicate into a crusher for crushing, then add the crushed solid sodium silicate into deionized water for stirring, and heat during the stirring process;

[0007] Prepare sulfuric acid with a concentration of 8% to 10%. During the preparation process, use a magnetic stirrer to stir the concentrated sulfuric acid and water, and control the temperature of the solution during the stirring process. Both are used to prepare reaction seed crystals;

[0008] S2. When adding industrial water to the reactor, the reactor needs to be cleaned first, rinsed with clean water, and then rinsed multiple times with deionized water. Industrial water accounting for 10% of the volume of the reactor is added to the reactor as reaction bottom water, and the prepared sodium silicate solution is added. During the process of adding the sodium silicate solution to the reactor, the stirring device of the reactor is started to stir the sodium silicate solution and the industrial water to mix the sodium silicate solution and the industrial water;

[0009] The reaction temperature was set at 80°C, the stirring rate was within the range of 70 r / min to 100 r / min, and the sulfuric acid solution was added dropwise. During the reaction, the pH value of the reaction system was monitored in real time using an online pH monitor until the pH value of the reaction system reached the range of 7.5 to 8.5. Then, the acid addition was stopped and the reaction system volume was controlled to occupy 20% of the reactor. The reaction time was 20 min to complete the seed crystal preparation.

[0010] S3, selecting solid sodium silicate with a modulus of 3.3 to 3.5 and preparing a water glass solution with a concentration of 15 wt% to 20 wt%. During the preparation process, the solid sodium silicate is first placed in a crusher for crushing, and then the crushed solid sodium silicate is added to deionized water for stirring, and heating is performed during the stirring process;

[0011] A dilute sulfuric acid solution with a concentration of 10wt% to 15wt% is prepared by using a magnetic stirrer to stir the concentrated sulfuric acid and water, and the temperature of the solution is controlled during the stirring process. Both are reserved for the subsequent reaction section;

[0012] S4, keeping the reaction stirring rate unchanged, the reaction temperature is reduced to within the range of 50°C to 60°C, and then the sulfuric acid solution and the water glass solution configured in step S3 are added, the addition rate of the alkali solution is kept greater than the addition rate of the acid solution, the pH value of the reaction system is controlled within the range of 9.0 to 10.0, and the pH value of the reaction system is monitored in real time using a high-precision pH monitor until the volume of the reaction system accounts for 70% of the reactor, and the reaction time is controlled to be completed within 60min to 80min;

[0013] S5. After the reaction is completed, sulfuric acid solution is continued to be added until the pH value of the reaction system is controlled within the range of 4.0 to 5.0, and acid addition is stopped. The reaction system is aged for 20 to 30 minutes. During the aging process, the temperature in the reactor is kept stable at 30° C. to 35° C., and the reaction is completed.

[0014] S6. After filter pressing and washing, the reaction liquid is sent to a pulper to obtain a thick slurry. During the filter pressing, a filter cloth with a pore size of 0.1 μm to 0.3 μm is used for filter pressing, and deionized water is used for washing multiple times during the washing process;

[0015] S7. The concentrated slurry is sent to a spray dryer for drying, using hot air from natural gas combustion as a heat source to obtain the target product.

[0016] Furthermore, in step S1, solid sodium silicate is crushed to a particle size of 5 mm, sieved through an 80-mesh sieve, and continuously stirred at a speed of 150 r / min to 200 r / min using a mechanical stirrer. During the stirring process, the temperature is heated to 50° C., and the stirring time is continued for 1 h to 1.5 h.

[0017] When preparing sulfuric acid with a concentration of 8% to 10%, use a magnetic stirrer to stir at a speed of 100 r / min to 120 r / min, and cool the solution at the same time to maintain the solution temperature at 20° C. to 25° C., and continue stirring for 30 minutes to 45 minutes.

[0018] Furthermore, in step S2, the industrial water is softened using a membrane softening method to reduce the content of calcium and magnesium ions in the water;

[0019] Rinse 3 to 5 times with deionized water;

[0020] When adding sulfuric acid solution, the dropping speed is 5ml / min~8ml / min;

[0021] When the volume of the reaction system reaches 20% of the reactor, a liquid level sensor is used to monitor the volume change in real time.

[0022] Furthermore, in step S3, the solid sodium silicate is crushed to a particle size of 5 mm, sieved through an 80-mesh sieve, and continuously stirred at a speed of 120 r / min to 150 r / min using a mechanical stirrer. During the stirring process, the temperature is heated to 50° C., and the stirring time is continued for 1.5 h to 2 h;

[0023] When preparing sulfuric acid with a concentration of 10% to 15%, use a magnetic stirrer to stir at a speed of 100 r / min to 130 r / min, while cooling the solution to maintain the solution temperature at 20° C. to 25° C., and continue stirring for 40 minutes to 50 minutes.

[0024] Furthermore, in step S4, the cooling rate is controlled at 1°C / min to 2°C / min;

[0025] The addition rate of sodium silicate solution is 10% to 20% faster than that of dilute sulfuric acid solution;

[0026] High-precision pH monitor with a monitoring frequency of once every 20 seconds.

[0027] Furthermore, in step S5, during the aging process, the stirring speed is maintained at 10 r / min to 20 r / min;

[0028] The pH value was monitored in real time using an online pH monitor at a frequency of every 15 seconds.

[0029] Furthermore, in step S6, during the filter press, the applied pressure is 0.3 MPa to 0.5 MPa, and the pressure is gradually increased in stages, with the initial pressure being 0.1 MPa, and increasing by 0.1 MPa every 5 to 10 minutes;

[0030] During washing, use deionized water for 3 to 5 times, and the amount of deionized water used in each washing is 1 to 1.5 times the volume of the reaction solution;

[0031] During beating, the speed of the beater is set to 800r / min to 1000r / min, and the beating time is 10min to 15min;

[0032] During the beating process, a high-speed stirrer is used for stirring, the stirring speed is 500r / min to 600r / min, and the stirring time is 20min to 30min.

[0033] Furthermore, in step S7, during the spray drying process, the temperature of the hot air is controlled to be between 150° C. and 200° C., the air inlet speed is 5 m / s to 8 m / s, and the air outlet speed is 3 m / s to 5 m / s.

[0034] The beneficial effects of the present invention are:

[0035] 1. The target product of the present invention has a high specific surface area, reaching the range of 200-240m2 / g, and a dispersion grade of 9.8 or above.

[0036] 2. The mechanical strength of the present invention is significantly improved, with the tensile strength reaching above 25 MPa and the 300% elongation stress reaching above 7.0 MPa.

[0037] 3. The present invention adopts a two-step seed crystal preparation process to make the product microstructure more regular, obtain a higher surface area and higher mechanical properties. DETAILED DESCRIPTION

[0038] In order to further understand the content, characteristics and effects of the present invention, the following examples are given and described in detail as follows.

[0039] Example 1:

[0040] A method for preparing precipitated silica for heavy trucks comprises the following steps:

[0041] The following steps are involved:

[0042] S1. Select solid sodium silicate with a modulus of 3.3 and prepare a sodium silicate solution with a concentration of 30 wt%. During the preparation process, first put the solid sodium silicate into a crusher for crushing, crush the solid sodium silicate to a particle size of 5 mm, then sieve it through an 80-mesh sieve, and then add the crushed solid sodium silicate to deionized water for stirring. Use a mechanical stirrer to continuously stir at a speed of 150 r / min. During the stirring process, heat the temperature to 50° C. and stir for 1 hour.

[0043] Prepare 8% sulfuric acid. During the preparation process, use a magnetic stirrer to stir the concentrated sulfuric acid and water at a speed of 100 r / min. During the stirring process, control the temperature of the solution to maintain the solution temperature at 20°C. Stir continuously for 30 minutes. Both are used for preparing reaction seed crystals.

[0044] S2. First, the industrial water is softened using a membrane softening method to reduce the content of calcium and magnesium ions in the water. When the industrial water is added to the reactor, the reactor needs to be cleaned first, rinsed with clean water, and then rinsed with deionized water for 3 to 5 times. Industrial water accounting for 10% of the volume of the reactor is added to the reactor as reaction bottom water, and the prepared sodium silicate solution is added. During the process of adding the sodium silicate solution to the reactor, the stirring device of the reactor is started to stir the sodium silicate solution and the industrial water to mix the sodium silicate solution and the industrial water;

[0045] The reaction temperature was set at 80°C, the stirring rate was within the range of 70 r / min, and the sulfuric acid solution was added dropwise at a rate of 5 ml / min. During the reaction, the pH value of the reaction system was monitored in real time using an online pH monitor until the pH value of the reaction system reached a range of 7.5 to 8.5, at which time the addition of acid was stopped. The volume of the reaction system was controlled to occupy 20% of the reactor, and when the volume of the reaction system reached 20% of the reactor, the volume change was monitored in real time using a liquid level sensor. The reaction time was 20 minutes, and the seed crystal preparation was completed.

[0046] S3. Select solid sodium silicate with a modulus of 3.3 and prepare a water glass solution with a concentration of 15 wt%. During the preparation process, first put the solid sodium silicate into a crusher for crushing, crush the solid sodium silicate to a particle size of 5 mm, then add the crushed solid sodium silicate to deionized water and stir, use a mechanical stirrer to continuously stir at a speed of 120 r / min, and heat during the stirring process to 50° C., and stir for 1.5 hours;

[0047] A 10 wt% dilute sulfuric acid solution was prepared by stirring the concentrated sulfuric acid and water using a magnetic stirrer at a stirring speed of 100 r / min. The temperature of the solution was controlled during the stirring process and maintained at 20°C. Stirring was continued for 40 minutes. Both were reserved for the subsequent reaction section.

[0048] S4, keeping the reaction stirring speed constant, the reaction temperature was reduced to within 50 ℃, the cooling rate was controlled at 1 ℃ / min~2 ℃ / min, the sulfuric acid solution and the water glass solution configured in step S3 were subsequently added, the addition rate of the alkali solution was kept greater than the addition rate of the acid solution, the addition rate of the sodium silicate solution was 10% faster than the addition rate of the dilute sulfuric acid solution, the pH value of the reaction system was controlled within the range of 9.0~10.0, a high-precision pH monitor was used to monitor the pH value of the reaction system in real time, the monitoring frequency was once every 20 seconds, until the volume of the reaction system accounted for 70% of the reactor, and the reaction time was controlled to complete within 60min~80min;

[0049] S5. After the reaction is completed, sulfuric acid solution is continued to be added, and the pH value is monitored in real time using an online pH monitor at a frequency of once every 15 seconds until the pH value of the reaction system is controlled within the range of 4.0 to 5.0. The addition of acid is stopped, and the reaction system is aged for 20 minutes. During the aging process, the temperature in the reactor is kept stable at 30° C., and the stirring speed is maintained at 10 r / min. The reaction is completed;

[0050] S6. After filter pressing and washing, the reaction liquid is sent to a pulper to obtain a thick slurry. During the filter pressing, a filter cloth with a pore size of 0.1 μm to 0.3 μm is used for filter pressing. The pressure applied during filtration is 0.3 MPa to 0.5 MPa. The pressure is gradually increased in stages. The initial pressure is 0.1 MPa, and it is increased by 0.1 MPa every 5 min to 10 min. During the washing process, deionized water is used for washing 3 to 5 times. During each washing, the amount of deionized water used is 1 to 1.5 times the volume of the reaction liquid.

[0051] During beating, the speed of the beater is set to 800r / min~1000r / min, the beating time is 10min~15min, and during the beating process, a high-speed stirrer is used for stirring, the stirring speed is 500r / min~600r / min, and the stirring time is 20min~30min;

[0052] S7. The concentrated slurry is sent to the spray dryer for drying. Hot air from natural gas combustion is used as the heat source. The temperature of the hot air is controlled between 150℃ and 200℃, the air inlet speed is 5m / s to 8m / s, and the air outlet speed is 3m / s to 5m / s to obtain the target product.

[0053] Example 2:

[0054] A method for preparing precipitated silica for heavy trucks comprises the following steps:

[0055] S1. Select solid sodium silicate with a modulus of 3.4 and prepare a sodium silicate solution with a concentration of 32 wt%. During the preparation process, first place the solid sodium silicate in a crusher for crushing, crush the solid sodium silicate to a particle size of 5 mm, then sieve through an 80-mesh sieve, and then add the crushed solid sodium silicate to deionized water for stirring. Use a mechanical stirrer to continuously stir at a speed of 170 r / min. During the stirring process, the temperature is heated to 50° C. and the stirring time is continued for 1.7 hours.

[0056] Prepare 9% sulfuric acid. During the preparation process, use a magnetic stirrer to stir the concentrated sulfuric acid and water at a speed of 110 r / min. During the stirring process, control the temperature of the solution to maintain the solution temperature at 22° C. and continue stirring for 40 minutes. Both are used for preparing reaction seed crystals;

[0057] S2. First, the industrial water is softened using a membrane softening method to reduce the content of calcium and magnesium ions in the water. When the industrial water is added to the reactor, the reactor needs to be cleaned first, rinsed with clean water, and then rinsed with deionized water for 3 to 5 times. Industrial water accounting for 10% of the volume of the reactor is added to the reactor as reaction bottom water, and the prepared sodium silicate solution is added. During the process of adding the sodium silicate solution to the reactor, the stirring device of the reactor is started to stir the sodium silicate solution and the industrial water to mix the sodium silicate solution and the industrial water;

[0058] The reaction temperature was set at 80°C, the stirring rate was within the range of 85 r / min, and the sulfuric acid solution was added dropwise at a rate of 7 ml / min. During the reaction, the pH value of the reaction system was monitored in real time using an online pH monitor until the pH value of the reaction system reached a range of 7.5 to 8.5, at which time the addition of acid was stopped. The volume of the reaction system was controlled to occupy 20% of the reactor, and when the volume of the reaction system reached 20% of the reactor, the volume change was monitored in real time using a liquid level sensor. The reaction time was 20 minutes, and the seed crystal preparation was completed.

[0059] S3. Select solid sodium silicate with a modulus of 3.2 and prepare a water glass solution with a concentration of 17 wt%. During the preparation process, first put the solid sodium silicate into a crusher for crushing, crushing the solid sodium silicate to a particle size of 5 mm, then add the crushed solid sodium silicate to deionized water and stir, use a mechanical stirrer to continuously stir at a speed of 135 r / min, and heat during the stirring process to 50° C., and stir for 1.7 hours;

[0060] A 13wt% dilute sulfuric acid solution was prepared by stirring the concentrated sulfuric acid and water using a magnetic stirrer at a stirring speed of 110 r / min. The temperature of the solution was controlled during the stirring process and maintained at 23°C. Stirring was continued for 45 minutes. Both were reserved for the subsequent reaction section.

[0061] S4, keeping the reaction stirring speed constant, the reaction temperature was reduced to within the range of 55 ℃, the cooling rate was controlled at 1 ℃ / min~2 ℃ / min, the sulfuric acid solution and the water glass solution configured in step S3 were subsequently added, the addition rate of the alkali solution was kept greater than the addition rate of the acid solution, the addition rate of the sodium silicate solution was 15% faster than the addition rate of the dilute sulfuric acid solution, the pH value of the reaction system was controlled within the range of 9.0~10.0, a high-precision pH monitor was used to monitor the pH value of the reaction system in real time, the monitoring frequency was once every 20 seconds, until the volume of the reaction system accounted for 70% of the reactor, and the reaction time was controlled to complete within 60min~80min;

[0062] S5. After the reaction is completed, sulfuric acid solution is continued to be added, and the pH value is monitored in real time using an online pH monitor at a frequency of once every 15 seconds until the pH value of the reaction system is controlled within the range of 4.0 to 5.0. Then, the addition of acid is stopped, and the reaction system is aged for 15 minutes. During the aging process, the temperature in the reactor is kept stable at 32° C., and the stirring speed is maintained at 15 r / min. The reaction is completed;

[0063] S6. After filter pressing and washing, the reaction liquid is sent to a pulper to obtain a thick slurry. During the filter pressing, a filter cloth with a pore size of 0.1 μm to 0.3 μm is used for filter pressing. The pressure applied during filtration is 0.3 MPa to 0.5 MPa. The pressure is gradually increased in stages. The initial pressure is 0.1 MPa, and it is increased by 0.1 MPa every 5 min to 10 min. During the washing process, deionized water is used for washing 3 to 5 times. During each washing, the amount of deionized water used is 1 to 1.5 times the volume of the reaction liquid.

[0064] During beating, the speed of the beater is set to 800r / min~1000r / min, the beating time is 10min~15min, and during the beating process, a high-speed stirrer is used for stirring, the stirring speed is 500r / min~600r / min, and the stirring time is 20min~30min;

[0065] S7. The concentrated slurry is sent to the spray dryer for drying. Hot air from natural gas combustion is used as the heat source. The temperature of the hot air is controlled between 150℃ and 200℃, the air inlet speed is 5m / s to 8m / s, and the air outlet speed is 3m / s to 5m / s to obtain the target product.

[0066] Example 3:

[0067] A method for preparing precipitated silica for heavy trucks comprises the following steps:

[0068] S1. Select solid sodium silicate with a modulus of 3.5 and prepare a sodium silicate solution with a concentration of 35 wt%. During the preparation process, first put the solid sodium silicate into a crusher for crushing, crush the solid sodium silicate to a particle size of 5 mm, then sieve it through an 80-mesh sieve, and then add the crushed solid sodium silicate to deionized water for stirring. Use a mechanical stirrer to continuously stir at a speed of 200 r / min. During the stirring process, heat the temperature to 50° C. and stir for 1.5 hours.

[0069] Prepare 10% sulfuric acid. During the preparation process, use a magnetic stirrer to stir the concentrated sulfuric acid and water at a speed of 120 r / min. During the stirring process, control the temperature of the solution to maintain the solution temperature at 25°C. Stir continuously for 45 minutes. Both are used for preparing reaction seed crystals.

[0070] S2. First, the industrial water is softened using a membrane softening method to reduce the content of calcium and magnesium ions in the water. When the industrial water is added to the reactor, the reactor needs to be cleaned first, rinsed with clean water, and then rinsed with deionized water for 3 to 5 times. Industrial water accounting for 10% of the volume of the reactor is added to the reactor as reaction bottom water, and the prepared sodium silicate solution is added. During the process of adding the sodium silicate solution to the reactor, the stirring device of the reactor is started to stir the sodium silicate solution and the industrial water to mix the sodium silicate solution and the industrial water;

[0071] The reaction temperature was set at 80°C, the stirring rate was within the range of 100 r / min, and the sulfuric acid solution was added dropwise at a rate of 8 ml / min. During the reaction, the pH value of the reaction system was monitored in real time using an online pH monitor until the pH value of the reaction system reached a range of 7.5 to 8.5, at which time the addition of acid was stopped. The volume of the reaction system was controlled to occupy 20% of the reactor, and when the volume of the reaction system reached 20% of the reactor, the volume change was monitored in real time using a liquid level sensor. The reaction time was 20 min, and the seed crystal preparation was completed.

[0072] S3. Select solid sodium silicate with a modulus of 3.5 and prepare a water glass solution with a concentration of 20 wt%. During the preparation process, first put the solid sodium silicate into a crusher for crushing, crushing the solid sodium silicate to a particle size of 5 mm, then add the crushed solid sodium silicate into deionized water and stir, use a mechanical stirrer to continuously stir at a speed of 150 r / min, and heat during the stirring process to 50° C., and stir for 2 hours;

[0073] A 15wt% dilute sulfuric acid solution was prepared by stirring the concentrated sulfuric acid and water with a magnetic stirrer at a stirring speed of 1130 r / min. The temperature of the solution was controlled during the stirring process and maintained at 25°C. Stirring was continued for 50 minutes. Both were reserved for the subsequent reaction section.

[0074] S4, keeping the reaction stirring speed constant, the reaction temperature was reduced to within 60 ℃, the cooling rate was controlled at 1 ℃ / min~2 ℃ / min, the sulfuric acid solution and the water glass solution configured in step S3 were subsequently added, the addition rate of the alkali solution was kept greater than the addition rate of the acid solution, the addition rate of the sodium silicate solution was 20% faster than the addition rate of the dilute sulfuric acid solution, the pH value of the reaction system was controlled within the range of 9.0~10.0, a high-precision pH monitor was used to monitor the pH value of the reaction system in real time, the monitoring frequency was once every 20 seconds, until the volume of the reaction system accounted for 70% of the reactor, and the reaction time was controlled to complete within 60min~80min;

[0075] S5. After the reaction is completed, sulfuric acid solution is continued to be added, and the pH value is monitored in real time using an online pH monitor at a frequency of once every 15 seconds until the pH value of the reaction system is controlled within the range of 4.0 to 5.0. The addition of acid is stopped, and the reaction system is aged for 30 minutes. During the aging process, the temperature in the reactor is kept stable at 335° C. and the stirring speed is maintained at 20 r / min. The reaction is completed;

[0076] S6. After filter pressing and washing, the reaction liquid is sent to a pulper to obtain a thick slurry. During the filter pressing, a filter cloth with a pore size of 0.1 μm to 0.3 μm is used for filter pressing. The pressure applied during filtration is 0.3 MPa to 0.5 MPa. The pressure is gradually increased in stages. The initial pressure is 0.1 MPa, and it is increased by 0.1 MPa every 5 min to 10 min. During the washing process, deionized water is used for washing 3 to 5 times. During each washing, the amount of deionized water used is 1 to 1.5 times the volume of the reaction liquid.

[0077] During beating, the speed of the beater is set to 800r / min~1000r / min, the beating time is 10min~15min, and during the beating process, a high-speed stirrer is used for stirring, the stirring speed is 500r / min~600r / min, and the stirring time is 20min~30min;

[0078] S7. The concentrated slurry is sent to the spray dryer for drying. Hot air from natural gas combustion is used as the heat source. The temperature of the hot air is controlled between 150℃ and 200℃, the air inlet speed is 5m / s to 8m / s, and the air outlet speed is 3m / s to 5m / s to obtain the target product.

[0079] Table 1 is a comparison of silicon dioxide in Examples 1 to 3.

[0080]

[0081] From the above embodiments, it can be seen that under the same conditions, the present invention adopts a two-step seed crystal preparation process to make the product microstructure more regular, obtain a higher surface area and higher mechanical properties.

[0082] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing precipitated silica for heavy trucks, characterized by: The following steps are involved: S1. Select solid sodium silicate with a modulus of 3.3 to 3.5 and prepare a sodium silicate solution with a concentration of 30 wt% to 35 wt%. During the preparation process, first put the solid sodium silicate into a crusher for crushing, then add the crushed solid sodium silicate into deionized water for stirring, and heat during the stirring process; Prepare sulfuric acid with a concentration of 8% to 10%. During the preparation process, use a magnetic stirrer to stir the concentrated sulfuric acid and water, and control the temperature of the solution during the stirring process. Both are used to prepare reaction seed crystals; S2. When adding industrial water to the reactor, the reactor needs to be cleaned first, rinsed with clean water, and then rinsed multiple times with deionized water. Industrial water accounting for 10% of the volume of the reactor is added to the reactor as reaction bottom water, and the prepared sodium silicate solution is added. During the process of adding the sodium silicate solution to the reactor, the stirring device of the reactor is started to stir the sodium silicate solution and the industrial water to mix the sodium silicate solution and the industrial water; The reaction temperature was set at 80°C, the stirring rate was within the range of 70 r / min to 100 r / min, and the sulfuric acid solution was added dropwise. During the reaction, the pH value of the reaction system was monitored in real time using an online pH monitor until the pH value of the reaction system reached the range of 7.5 to 8.

5. Then, the acid addition was stopped and the reaction system volume was controlled to occupy 20% of the reactor. The reaction time was 20 min to complete the seed crystal preparation. S3, selecting solid sodium silicate with a modulus of 3.3 to 3.5 and preparing a water glass solution with a concentration of 15 wt% to 20 wt%. During the preparation process, the solid sodium silicate is first placed in a crusher for crushing, and then the crushed solid sodium silicate is added to deionized water for stirring, and heating is performed during the stirring process; A dilute sulfuric acid solution with a concentration of 10wt% to 15wt% is prepared by using a magnetic stirrer to stir the concentrated sulfuric acid and water, and the temperature of the solution is controlled during the stirring process. Both are reserved for the subsequent reaction section; S4, keeping the reaction stirring rate unchanged, the reaction temperature is reduced to within the range of 50°C to 60°C, and then the sulfuric acid solution and the water glass solution configured in step S3 are added, the addition rate of the alkali solution is kept greater than the addition rate of the acid solution, the pH value of the reaction system is controlled within the range of 9.0 to 10.0, and the pH value of the reaction system is monitored in real time using a high-precision pH monitor until the volume of the reaction system accounts for 70% of the reactor, and the reaction time is controlled to be completed within 60min to 80min; S5. After the reaction is completed, sulfuric acid solution is continued to be added until the pH value of the reaction system is controlled within the range of 4.0 to 5.0, and acid addition is stopped. The reaction system is aged for 20 to 30 minutes. During the aging process, the temperature in the reactor is kept stable at 30° C. to 35° C., and the reaction is completed. S6. After filter pressing and washing, the reaction liquid is sent to a pulper to obtain a thick slurry. During the filter pressing, a filter cloth with a pore size of 0.1 μm to 0.3 μm is used for filter pressing, and deionized water is used for washing multiple times during the washing process; S7. The concentrated slurry is sent to a spray dryer for drying, using hot air from natural gas combustion as a heat source to obtain the target product.

2. The method for preparing precipitated silica for heavy trucks according to claim 1, wherein: In step S1, solid sodium silicate is crushed to a particle size of 5 mm, sieved through an 80-mesh sieve, and continuously stirred at a speed of 150 r / min to 200 r / min using a mechanical stirrer. During the stirring process, the temperature is heated to 50° C. and the stirring time is continued for 1 hour to 1.5 hours; When preparing sulfuric acid with a concentration of 8% to 10%, use a magnetic stirrer to stir at a speed of 100 r / min to 120 r / min, and cool the solution at the same time to maintain the solution temperature at 20° C. to 25° C., and continue stirring for 30 minutes to 45 minutes.

3. The method for preparing precipitated silica for heavy trucks according to claim 1, wherein: In step S2, the industrial water is softened using a membrane softening method to reduce the content of calcium and magnesium ions in the water; Rinse 3 to 5 times with deionized water; When adding sulfuric acid solution, the dropping speed is 5ml / min~8ml / min; When the volume of the reaction system reaches 20% of the reactor, a liquid level sensor is used to monitor the volume change in real time.

4. The method for preparing precipitated silica for heavy trucks according to claim 1, wherein: In step S3, solid sodium silicate is crushed to a particle size of 5 mm, sieved through an 80-mesh sieve, and continuously stirred at a speed of 120 r / min to 150 r / min using a mechanical stirrer. During the stirring process, the temperature is heated to 50° C. and the stirring time is continued for 1.5 h to 2 h. When preparing sulfuric acid with a concentration of 10% to 15%, use a magnetic stirrer to stir at a speed of 100 r / min to 130 r / min, while cooling the solution to maintain the solution temperature at 20° C. to 25° C., and continue stirring for 40 minutes to 50 minutes.

5. The method for preparing precipitated silica for heavy trucks according to claim 1, wherein: In step S4, the cooling rate is controlled at 1°C / min to 2°C / min; The addition rate of sodium silicate solution is 10% to 20% faster than that of dilute sulfuric acid solution; High-precision pH monitor with a monitoring frequency of once every 20 seconds.

6. The method for preparing precipitated silica for heavy trucks according to claim 1, wherein: In step S5, during the aging process, the stirring speed is maintained at 10 r / min to 20 r / min; The pH value was monitored in real time using an online pH monitor at a frequency of every 15 seconds.

7. The method for preparing precipitated silica for heavy trucks according to claim 1, wherein: In step S6, during the filter press, the applied pressure is 0.3 MPa to 0.5 MPa, and the pressure is gradually increased in stages. The initial pressure is 0.1 MPa, and the pressure is increased by 0.1 MPa every 5 to 10 minutes. During washing, use deionized water for 3 to 5 times, and the amount of deionized water used in each washing is 1 to 1.5 times the volume of the reaction solution; During beating, the speed of the beater is set to 800r / min to 1000r / min, and the beating time is 10min to 15min; During the beating process, a high-speed stirrer is used for stirring, the stirring speed is 500r / min to 600r / min, and the stirring time is 20min to 30min.

8. The method for preparing precipitated silica for heavy trucks according to claim 1, wherein: In step S7, during the spray drying process, the temperature of the hot air is controlled to be between 150° C. and 200° C., the air inlet speed is 5 m / s to 8 m / s, and the air outlet speed is 3 m / s to 5 m / s.

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