A carrier silica gel and its preparation method and application

Abstract

The application provides a carrier silica gel and a preparation method and application thereof, and belongs to the technical field of polyolefin catalyst carrier materials. A silicate aqueous solution and an inorganic acid are mixed to serve as a mother liquor, the silicate aqueous solution and the inorganic acid aqueous solution are added into the mother liquor which is aged through water bath at a certain temperature, an organic alcohol aqueous solution is added for multiple times in small amounts during the formation of the hydrogel, the silicate aqueous solution and the inorganic acid aqueous solution are continuously added after sufficient stirring, ethanol is added during the aging process, the silica gel carrier is obtained through washing, drying and activation after using anhydrous ethanol as a medium for washing and drying in an oven. The method can effectively improve the adding speed of the silicate aqueous solution and the inorganic acid aqueous solution while meeting the requirement of sufficient growth of colloidal particles. The silica gel carrier obtained through the method has good specific surface area, average pore diameter, pore volume and bulk density, and the pore structure is more excellent.

Description

Technical Field

[0001] The present application belongs to the technical field of polyolefin catalyst carrier materials, and more specifically, relates to a carrier silica gel and its preparation method and application. Background Art

[0002] The hallmark and core of technological progress in the polyolefin industry lies in the development of catalysts and catalytic technologies. The technological strength and production level of a country's petrochemical industry can be largely reflected by the scale of its polyolefin production, the number of brands it produces, and the level of its production technology. Polyolefin resins play a vital role in everything from industrial and agricultural production to the construction of national defense facilities and everyday products. A review of the history of the polyolefin industry's development and progress clearly reveals that the expansion of polyolefin production scale, the reduction of production costs, the simplification of production processes, and the improvement of product performance are all closely related to the development and application of new catalysts and catalytic technologies. Metallocene catalysts possess an ideal single active center. By modifying their ligands, the electronegativity and steric environment of the active center can be altered, allowing precise control of molecular weight, molecular weight distribution, comonomer content, distribution along the backbone, and crystal structure. To achieve optimal performance of supported metallocene catalysts, it is essential to control the physical properties of the support, including strength, density, total pore volume, pore distribution, pore size, particle size, and particle shape. These physical properties are closely related to each other. Therefore, when designing a catalyst, in order to optimize its performance under actual application conditions, it is necessary to comprehensively consider and balance its physical or chemical properties.

[0003] As a support material for polyolefin catalysts, silica gel plays a prominent role in catalyst preparation and the synthesis of polyolefin resins. Therefore, research on silica gel, the most important support material for polyolefin catalysts, is crucial for promoting the development of the polyolefin industry. To date, my country's existing Unipol process polyethylene production units and Phillips slurry loop process HDPE production units rely on imported silica gel as catalyst supports. Grace, a US company, is a world leader in this field, with its Davison-955 silica gel commanding nearly the entire global market share for silica gel used in polyethylene catalyst supports. Therefore, research and development of superior silica gel supports is crucial.

[0004] Patent US3959174 uses ammonia, monohydric alcohols, dihydric alcohols, ketones, and salts as additives in the preparation of silica gel carriers to reduce the dielectric constant of the hydrosol system. Patents US4152503, US4436883, US3948806, US3099457, US4081407, US4246139, etc. discuss azeotropic distillation technology, attempting to effectively solve the problem of effectively avoiding shrinkage and collapse of the pore structure when removing water from the hydrogel. Patent CN101624431 introduces a method for preparing a special silica gel carrier for ethylene polymerization catalysts using a slurry process. The method involves reacting a sodium silicate aqueous solution and sulfuric acid in a certain proportion for 1-5 hours, adding an organic solvent (one or more of ethyl acetate, glycerol, acetone, and trichloroethane), adjusting the pH with an inorganic acid, and washing and spray drying to obtain a silica gel carrier.

[0005] The above methods still have some shortcomings, such as the use of additives to reduce the dielectric constant of the hydrosol system, cumbersome procedures, high solvent consumption, and difficulty in recovery. Azeotropic distillation also suffers from long distillation times, expensive solvents, and high energy consumption. Thermal spray drying also suffers from high costs, long experimental cycles, and low yields. Summary of the Invention

[0006] The purpose of this application is to provide a carrier silica gel and its preparation method and application. The silica gel carrier provided in this application has good specific surface area, average pore size, pore volume and bulk density, and has a better pore structure.

[0007] To achieve the above-mentioned objectives, the first aspect of the present application provides a method for preparing a carrier silica gel, wherein a silicate aqueous solution and an inorganic acid are mixed as a mother liquor, aged in a water bath at a certain temperature, and the silicate and inorganic acid aqueous solutions are added to the water bath-aged mother liquor in parallel. During the hydrogel formation process, an organic alcohol aqueous solution is added in small amounts multiple times, and after sufficient stirring, the silicate aqueous solution and the inorganic acid aqueous solution are continued to be added. Ethanol is added during the aging process, and anhydrous ethanol is used as a medium for washing and drying in an oven. After washing, drying, and activation, a silica gel product is obtained, and then silica gel particles with a suitable particle size are screened through a molecular sieve to be used as a carrier silica gel for a polyolefin metallocene catalyst. The preparation method comprises the following steps:

[0008] S1. Adding a mixed mother liquor containing silicate and inorganic acid to a reactor, adjusting the pH value of the mixed mother liquor to 9-13 under stirring conditions, and pre-reacting the mixed mother liquor at 30-70° C. for 0.5-1 h;

[0009] S2, adding a silicate aqueous solution and an inorganic acid aqueous solution to the mixed mother liquor after the pre-reaction in parallel, and reacting the reaction system at 50-100° C.;

[0010] S3. After observing the formation of hydrogel in the reaction kettle, stop adding the silicate aqueous solution and the inorganic acid aqueous solution, add an organic alcohol aqueous solution containing 20-30% of organic alcohol, stir and mix, and then continue to add the silicate aqueous solution and the inorganic acid aqueous solution to allow the reaction system to continue reacting;

[0011] S4, repeating step S3 at least twice. After the reaction is completed, lowering the temperature of the reaction system by 5 to 15° C., adding 20 to 100% ethanol aqueous solution, adjusting the pH to 11 to 12, and aging the reaction for 1 to 5 hours to obtain a hydrogel;

[0012] S5. Wash the prepared hydrogel multiple times with anhydrous ethanol, add anhydrous ethanol to the washed hydrogel, and evenly disperse the hydrogel in the anhydrous ethanol, then dry it, and activate it at 700-1000° C. to obtain carrier silica gel.

[0013] Furthermore, in step S1, the molar ratio of silicate to inorganic acid in the mixed mother liquor is 1:1 to 1:10.

[0014] Furthermore, in step S2, the ratio of the amount of silicate added to the amount of inorganic acid is 1:1 to 1:10.

[0015] Furthermore, in step S2, the concentration of the silicate aqueous solution is 0.5 to 2 mol / L, and the concentration of the inorganic acid aqueous solution is 0.5 to 2 mol / L.

[0016] Furthermore, the flow rates of the silicate aqueous solution and the inorganic acid aqueous solution are both controlled at 10 to 1000 mL / min.

[0017] Furthermore, the stirring speed is 100 to 500 rpm.

[0018] Furthermore, in step S1, the silicate is at least one of sodium silicate and potassium silicate, and the inorganic acid is at least one of sulfuric acid and hydrochloric acid.

[0019] Furthermore, in step S3, the organic alcohol is any one of ethanol and n-butanol.

[0020] In a second aspect of the present application, a carrier silica gel is provided, which is obtained by any of the preparation methods described above.

[0021] The third aspect of the present application provides the use of the carrier silica gel prepared above in the preparation of polyolefin catalysts.

[0022] Compared with the existing technology, this application has the following technical effects:

[0023] The present invention discloses a method for preparing a carrier silica gel. A silicate aqueous solution and an inorganic acid aqueous solution are mixed as a mother liquor. The inorganic acid in the mother liquor pre-reacts with the silicate to form primary particles, which facilitates the subsequent formation and growth of a hydrogel. In this method, after the silicate aqueous solution and the inorganic acid aqueous solution form a hydrogel with the primary particles as the core, an organic alcohol aqueous solution is added in small amounts multiple times. After thorough stirring, the silicate and inorganic acid aqueous solutions are continued to be added. The addition of the organic alcohol aqueous solution increases the repulsive potential between the colloid particles, preventing aggregation, while thorough stirring promotes continued growth. The organic alcohol expands the spacing between the hydrogel's network structure, making the prepared hydrogel structure more porous, which contributes to a better pore structure in the resulting silica gel. During the reaction, small particles dissolve easily, while areas with curvature on the gel or particle surface are prone to aggregation. Areas where two particles contact each other are also susceptible to the aggregation of other particles due to their low solubility. The repeated addition of small amounts of the organic alcohol aqueous solution improves the uniformity of the hydrogel particles.

[0024] Most existing silica gel carrier preparation methods reduce the addition rate of the silicate solution and the inorganic acid solution to ensure sufficient growth of the colloid particles. However, this reduction in addition rate prolongs the reaction cycle, increases production costs, and is not conducive to continuous production. The present method, by adding small amounts of organic alcohol solution multiple times during the hydrogel formation stage and thoroughly stirring, can effectively increase the addition rate of the silicate solution and the inorganic acid solution while ensuring sufficient growth of the colloid particles.

[0025] The present method also makes full use of the aging time to create pores in the carrier silica gel in a relatively gentle manner through the volatility of ethanol. Furthermore, when anhydrous ethanol is used as the drying medium, the resulting silica gel carrier has a good specific surface area, average pore diameter, pore volume, and bulk density, and a more excellent pore structure. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0027] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0028] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0029] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0030] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.

[0031] Example 1

[0032] Example 1 of the present application provides a carrier silica gel and a preparation method thereof, comprising the following steps:

[0033] a. Take 10 mL of 40° Baume waterglass and 1 mL of 16.25% dilute sulfuric acid, diluted 100-fold, as the mother liquor. Place the mother liquor in a reactor and heat in a 70°C waterbath for 0.5 h. While heating in the waterbath, use mechanical stirring at 300 rpm. Add 100 mL each of 40° Baume waterglass and 16.25% dilute sulfuric acid to the reactor using a constant flow pump at a rate of 50 mL / min. The reaction temperature is 60°C, and the reaction time is 30 min. After a hydrogel appears in the reactor, stop adding the waterglass and dilute sulfuric acid. Add 10 mL of a 25% ethanol solution. Set the mechanical stirring speed to 300 rpm. After thorough stirring, continue adding the waterglass and dilute sulfuric acid. After the hydrogel appears, stop adding the waterglass and dilute sulfuric acid. Add 30 mL of a 25% ethanol solution and stir thoroughly. Repeat this process three times.

[0034] b. Continue adding 10 mL of anhydrous ethanol and maintain the water bath temperature at 60°C for 3.0 hours to allow sufficient aging time for the generated hydrogel. After aging, the hydrogel was washed three times with anhydrous ethanol. Anhydrous ethanol was then added to the washed hydrogel. The hydrogel was evenly dispersed in the anhydrous ethanol using a homogenizer and then dried in an oven at 50°C. The sample was placed in a tube furnace and heated at 600°C for 2 hours for activation to obtain a polyolefin metallocene catalyst support silica gel.

[0035] Example 2

[0036] Example 2 of the present application provides a carrier silica gel and a preparation method thereof, comprising the following steps:

[0037] a. Take 10 mL of 40° Baume waterglass and 1 mL of 16.25% dilute sulfuric acid, diluted 100-fold, as the mother liquor. Place the mother liquor in a reactor and heat in a 70°C waterbath for 0.5 h. While heating in the waterbath, use mechanical stirring at 300 rpm. Add 100 mL each of 40° Baume waterglass and 16.25% dilute sulfuric acid to the reactor using a constant flow pump at a rate of 50 mL / min. The reaction temperature is 60°C, and the reaction time is 30 min. After a hydrogel appears in the reactor, stop adding the waterglass and dilute sulfuric acid. Add 20 mL of a 25% ethanol solution. Set the mechanical stirring speed to 300 rpm. After thorough stirring, continue adding the waterglass and dilute sulfuric acid. After the hydrogel appears, stop adding the waterglass and dilute sulfuric acid. Add 30 mL of a 25% ethanol solution and stir thoroughly. Repeat this process three times.

[0038] b. Continue adding 10 mL of anhydrous ethanol and maintain the water bath temperature at 60°C for 3.0 hours to allow sufficient aging time for the generated hydrogel. After aging, the hydrogel was washed three times with anhydrous ethanol. Anhydrous ethanol was then added to the washed hydrogel. The hydrogel was evenly dispersed in the anhydrous ethanol using a homogenizer and then dried in an oven at 50°C. The sample was placed in a tube furnace and heated at 600°C for 2 hours for activation to obtain a polyolefin metallocene catalyst support silica gel.

[0039] Example 3

[0040] Example 3 of the present application provides a carrier silica gel and a preparation method thereof, comprising the following steps:

[0041] a. Take 10 mL of 40° Baume waterglass and 1 mL of 16.25% dilute sulfuric acid, diluted 100-fold, as the mother liquor. Place the mother liquor in a reactor and heat in a 70°C waterbath for 0.5 h. While heating in the waterbath, use mechanical stirring at 300 rpm. Add 100 mL each of 40° Baume waterglass and 16.25% dilute sulfuric acid to the reactor using a constant flow pump at a rate of 50 mL / min. The reaction temperature is 60°C, and the reaction time is 30 min. After a hydrogel appears in the reactor, stop adding the waterglass and dilute sulfuric acid. Add 30 mL of a 25% ethanol solution. Set the mechanical stirring speed to 300 rpm. After thorough stirring, continue adding the waterglass and dilute sulfuric acid. After a hydrogel appears, stop adding the waterglass and dilute sulfuric acid. Add 30 mL of a 25% ethanol solution and stir thoroughly. Repeat this process three times.

[0042] b, continue to add 10 mL of anhydrous ethanol, keep the water bath temperature at 60°C, and water bath for 3.0 h to give the hydrogel sufficient aging time. After aging, the hydrogel is washed with anhydrous ethanol for three times, then anhydrous ethanol is added to the washed hydrogel, and the hydrogel is uniformly dispersed in anhydrous ethanol using a homogenizer, and then placed in an oven for drying at 50°C. The sample is placed in a tube furnace and heated at 600°C for 2 h to obtain a polyolefin metallocene catalyst carrier silica gel.

[0043] Example 4

[0044] The example 4 of the present application provides a carrier silica gel and a preparation method thereof, comprising the following steps:

[0045] a, take 10 mL of water glass with a Baume degree of 40 and 1 mL of dilute sulfuric acid with a concentration of 16.25% diluted 100 times as a mother liquor, and place the mother liquor in a reaction kettle, and water bath at 70°C for 0.5 h. While water bath heating, mechanical stirring is used with a stirring speed of 300 rpm. Take 100 mL of water glass with a Baume degree of 40 and 100 mL of dilute sulfuric acid with a concentration of 16.25%, and use a constant flow pump to add them into the reaction kettle at a speed of 50 mL / min. The reaction temperature is 60°C, and the reaction time is 30 min. After the hydrogel appears in the reaction kettle, stop adding the water glass and the dilute sulfuric acid, add 40 mL of an ethanol solution with a concentration of 25%, set the mechanical stirring speed to 300 rpm, fully stir, and then continue to add the water glass and the dilute sulfuric acid. After the hydrogel appears, stop adding the water glass and the dilute sulfuric acid, add 40 mL of an ethanol solution with a concentration of 25%, fully stir, and repeat the process three times.

[0046] b, continue to add 10 mL of anhydrous ethanol, keep the water bath temperature at 60°C, and water bath for 3.0 h to give the hydrogel sufficient aging time. After aging, the hydrogel is washed with anhydrous ethanol for three times, then anhydrous ethanol is added to the washed hydrogel, and the hydrogel is uniformly dispersed in anhydrous ethanol using a homogenizer, and then placed in an oven for drying at 50°C. The sample is placed in a tube furnace and heated at 600°C for 2 h to obtain a polyolefin metallocene catalyst carrier silica gel.

[0047] Comparative Example 1

[0048] a. Take 10 mL of 40° Baume waterglass and 1 mL of 16.25% dilute sulfuric acid, diluted 100-fold, as the mother liquor. Place the mother liquor in a reactor and heat in a 70°C waterbath for 0.5 h. While heating in the waterbath, use mechanical stirring at 300 rpm. Add 100 mL each of 40° Baume waterglass and 16.25% dilute sulfuric acid to the reactor using a constant flow pump at a rate of 50 mL / min. The reaction temperature is 60°C, and the reaction time is 30 min. After a hydrogel appears in the reactor, stop adding the waterglass and dilute sulfuric acid. Add 30 mL of a 25% ethanol solution. Set the mechanical stirring speed to 300 rpm. After thorough stirring, continue adding the waterglass and dilute sulfuric acid. After a hydrogel appears, stop adding the waterglass and dilute sulfuric acid. Add 30 mL of a 25% ethanol solution and stir thoroughly. Repeat this process three times.

[0049] b. Maintain the water bath temperature at 60°C for 3.0 hours to allow sufficient aging time for the generated hydrogel. After aging, wash the hydrogel three times with anhydrous ethanol. Add anhydrous ethanol to the washed hydrogel, homogenize it in the anhydrous ethanol, and dry it in an oven at 50°C. Activate the sample by heating it in a tube furnace at 600°C for 2 hours to obtain a polyolefin metallocene catalyst support silica gel.

[0050] Comparative Example 2

[0051] a. Take 10 mL of 40° Baume water glass and 1 mL of 16.25% dilute sulfuric acid, diluted 100-fold, as the mother liquor. Place the mother liquor in a reactor and heat in a 70°C water bath for 0.5 h. While heating in the water bath, use mechanical stirring at 300 rpm. Take 100 mL each of 40° Baume water glass and 16.25% dilute sulfuric acid and add them to the reactor at a constant flow rate of 50 mL / min using a constant flow pump. The reaction temperature is 60°C and the reaction time is 30 min.

[0052] b. After adding 10 mL of anhydrous ethanol, maintain the water bath temperature at 60°C for 3.0 hours to allow sufficient aging time for the resulting hydrogel. After aging, the hydrogel was washed three times with anhydrous ethanol. Anhydrous ethanol was then added to the washed hydrogel. The hydrogel was evenly dispersed in the anhydrous ethanol using a homogenizer and then dried in an oven at 50°C. The sample was placed in a tube furnace and heated at 600°C for 2 hours for activation to obtain a polyolefin metallocene catalyst support silica gel.

[0053] Comparative Example 3

[0054] a. Take 10 mL of 40° Baume waterglass and 1 mL of 16.25% dilute sulfuric acid, diluted 100-fold, as the mother liquor. Place the mother liquor in a reactor and heat in a 70°C waterbath for 0.5 h. While heating in the waterbath, use mechanical stirring at 300 rpm. Add 100 mL each of 40° Baume waterglass and 16.25% dilute sulfuric acid to the reactor using a constant flow pump at a rate of 50 mL / min. The reaction temperature is 60°C, and the reaction time is 30 min. After a hydrogel appears in the reactor, stop adding the waterglass and dilute sulfuric acid. Add 30 mL of a 25% ethanol solution. Set the mechanical stirring speed to 300 rpm. After thorough stirring, continue adding the waterglass and dilute sulfuric acid. After a hydrogel appears, stop adding the waterglass and dilute sulfuric acid. Add 30 mL of a 25% ethanol solution and stir thoroughly. Repeat this process three times.

[0055] b. Continue adding 10 mL of anhydrous ethanol and maintain the water bath temperature at 70°C for 3.0 hours to allow sufficient aging time for the resulting hydrogel. After aging, wash the hydrogel three times with deionized water to remove impurities. Oven dry the sample at 50°C for 8 hours using deionized water. Activate the sample in a tube furnace at 600°C for 2 hours to obtain a polyolefin metallocene catalyst support silica gel.

[0056] Comparative Example 4

[0057] a. Take 10mL of 40°Bé waterglass and 1mL of 16.25% dilute sulfuric acid, diluted 100-fold, as the mother liquor. Place the mother liquor in a reactor and heat in a 70°C waterbath for 0.5h. While heating in the waterbath, use mechanical stirring at 300rpm. Add 100mL each of 40°Bé waterglass and 16.25% dilute sulfuric acid to the reactor using a constant flow pump at a rate of 50mL / min. The reaction temperature is 60°C, and the reaction time is 30min. After a hydrogel appears in the reactor, stop adding the waterglass and dilute sulfuric acid. Add 30mL of a 25% ethanol solution. Set the mechanical stirring speed to 300rpm. After thorough stirring, continue adding the waterglass and dilute sulfuric acid. After a hydrogel appears, stop adding the waterglass and dilute sulfuric acid. Add 90mL of a 25% ethanol solution all at once and stir thoroughly.

[0058] b. Continue adding 10 mL of anhydrous ethanol and maintain the water bath temperature at 60°C for 3.0 hours to allow sufficient aging time for the generated hydrogel. After aging, the hydrogel was washed three times with anhydrous ethanol. Anhydrous ethanol was then added to the washed hydrogel. The hydrogel was evenly dispersed in the anhydrous ethanol using a homogenizer and then dried in an oven at 50°C. The sample was placed in a tube furnace and heated at 600°C for 2 hours for activation to obtain a polyolefin metallocene catalyst support silica gel.

[0059] The specific surface area, pore volume, average pore size, particle size and bulk density of the carrier silica gel prepared in Examples 1-4 and Comparative Examples 1-4 of the present application were tested, and the test results are shown in Table 1 below.

[0060] Table 1

[0061]

[0062] The test results of Example 3 and Comparative Example 1 show that the addition of ethanol during the aging stage can fully utilize the aging time and the volatility of ethanol to form pores in the carrier silica gel in a relatively mild manner.

[0063] The test results of Example 3 and Comparative Example 2 show that by adding ethanol aqueous solution multiple times during the hydrogel formation stage, the silica gel prepared has significant improvements in specific surface area, pore volume, and average pore size compared to the silica gel prepared without adding ethanol aqueous solution, and the particle size and packing density of the silica gel carrier that require attention are also improved to a certain extent.

[0064] The test results of Example 3 and Comparative Examples 1-2 show that the effect of adding ethanol in both the hydrosol formation stage and the aging stage on improving the physical and chemical properties of silica gel is significantly better than the effect of adding ethanol in small amounts and multiple times in the hydrogel formation stage or adding ethanol alone in the aging stage on improving the performance of silica gel.

[0065] The test results of Example 3 and Comparative Example 3 show that the preparation method of the embodiment of the present application uses anhydrous ethanol as a medium and uses an oven to dry the silica gel at 50°C. Compared with drying methods such as hot spray drying, it can reduce costs and increase yields; compared with water washing and drying, anhydrous ethanol can effectively form pores during the volatilization process, so that the obtained silica gel has a better pore structure.

[0066] The test results of Example 3 and Comparative Example 4 show that by adding ethanol aqueous solution multiple times during the hydrogel formation stage, the prepared carrier silica gel has certain improvements in specific surface area, pore volume, average pore size, particle size and bulk density compared to adding ethanol aqueous solution once.

[0067] The test results in Table 1 above demonstrate that pausing the reaction during hydrogel formation, adding an ethanol-water solution for thorough stirring, and then continuing the reaction effectively promotes full colloid particle growth, expands the spacing between the hydrogel network, and makes the prepared hydrogel structure more porous. Adding anhydrous ethanol during the aging process has a good pore-forming effect, resulting in a silica gel product with a good pore structure. The silica gel carrier obtained by oven drying using anhydrous ethanol as a medium exhibits superior pore volume, pore diameter, and specific surface area. The polyolefin metallocene catalyst carrier silica gel prepared using this method exhibits excellent specific surface area, average pore diameter, pore volume, particle size, and bulk density.

[0068] The above embodiments only express several implementation ways of the present application, and the description is specific and detailed, but it should not be understood as a limitation to the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing carrier silica gel, characterized in that: The following steps are involved: S1. Add a mixed mother liquor containing silicate and inorganic acid to a reactor, adjust the pH value of the mixed mother liquor to 9-13 under stirring conditions, and pre-react the mixed mother liquor at 30-70° C. for 0.5-1 h; S2. Adding a silicate aqueous solution and an inorganic acid aqueous solution to the mixed mother liquor after the pre-reaction in parallel, and reacting the reaction system at 50-100°C; S3. After observing the formation of hydrogel in the reactor, stop adding the silicate aqueous solution and the inorganic acid aqueous solution, add an organic alcohol aqueous solution containing 20-30% of organic alcohol, stir and mix, and then continue to add the silicate aqueous solution and the inorganic acid aqueous solution to allow the reaction system to continue reacting; S4. Repeat step S3 at least twice. After the reaction is completed, reduce the temperature of the reaction system by 5-15°C, add 20-100% ethanol aqueous solution, adjust the pH to 11-12, and age for 1-5 hours to obtain a hydrogel. S5, washing the prepared hydrogel multiple times with anhydrous ethanol, adding anhydrous ethanol to the washed hydrogel, and uniformly dispersing the hydrogel in the anhydrous ethanol, then drying, and activating at 700-1000° C. to obtain a carrier silica gel; In step S3, the organic alcohol is any one of ethanol and n-butanol.

2. The method for preparing a carrier silica gel according to claim 1, wherein: In step S1, the molar ratio of silicate to inorganic acid in the mixed mother liquor is 1:1 to 1:

10.

3. The method for preparing a carrier silica gel according to claim 1, wherein: In step S2, the ratio of the amount of silicate added to the amount of inorganic acid is 1:1 to 1:

10.

4. The method for preparing a carrier silica gel according to claim 1, wherein: In step S2, the concentration of the silicate aqueous solution is 0.5-2 mol / L, and the concentration of the inorganic acid aqueous solution is 0.5-2 mol / L.

5. The method for preparing a carrier silica gel according to claim 4, wherein: In step S2, the flow rates of the silicate aqueous solution and the inorganic acid aqueous solution are both controlled at 10-1000 mL / min.

6. The method for preparing a carrier silica gel according to claim 4, wherein: In step S1 or S3, the stirring speed is 100-500 rpm.

7. The method for preparing a carrier silica gel according to claim 1, wherein: In step S1, the silicate is at least one of sodium silicate and potassium silicate, and the inorganic acid is at least one of sulfuric acid and hydrochloric acid.

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