Preparation method of general precipitated silicon dioxide for rubber reinforcement

Abstract

The invention discloses a preparation method of rubber-reinforced general precipitated silica, which belongs to the silica preparation technology, and comprises the following steps: S1, preparing a sodium silicate solution with the concentration of 15-20wt%, adding secondary alkyl sodium sulfonate, and selecting 98% sulfuric acid as an acidifying agent; s2, firstly adding industrial water which is 1 / 6 of the volume of the reaction kettle into the reaction kettle, and heating the water in the reaction kettle; adding materials in the heating process, stirring in the material adding process until the reaction liquid reaches 2 / 3 of the volume of the reaction kettle, controlling the reaction time and keeping the reaction temperature; the pH value of a reaction system in the reaction kettle is regulated and controlled in a stepped manner; a surfactant secondary alkyl sodium sulfonate is added in the initial stage of the reaction as a reaction regulator, so that after the reaction process is finished, the silanol group of the obtained target product is controlled to be 4-6OH / nm < 2 >, and the mass ratio of 90% of particles is controlled to be more than 3mm.

Description

Technical Field

[0001] The invention belongs to the technical field of silicon dioxide preparation, and in particular relates to a method for preparing general precipitated silicon dioxide for rubber reinforcement. Background Art

[0002] Beer is a fermented wine made from malt and water as the main raw materials, hops (including hop products), and yeast fermentation. It contains carbon dioxide and can form foam. Beer is a low-alcohol wine, containing carbon dioxide, multiple amino acids, vitamins, low-molecular sugars, inorganic salts and various enzymes. It has the effects of sterilization, fatigue relief, and digestion. The alcohol content is very low, and drinking beer is not easy to get drunk and hurt the body. Drinking a small amount will be good for your health. Because it contains sensitive proteins and polyphenols and other substances, it is easy to form non-biological turbidity. Turbidity in beer will shorten the shelf life of the product and affect its appearance and taste.

[0003] Silica is a porous material. Its main characteristics are large surface area, many pores, large structural space, low surface tension, small viscosity-temperature coefficient, high compressibility, high gas permeability, etc. Silica has been widely used in the beer industry as a new environmentally friendly adsorbent. It can effectively remove turbid proteins in beer without affecting the quality of beer products. Compared with other filter aids, silica has the advantages of less addition and better effect. For this reason, we propose a method for preparing universal precipitated silica for rubber reinforcement. Summary of the invention

[0004] The present invention provides a method for preparing universal precipitated silica for rubber reinforcement, so as 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 general precipitated silica for rubber reinforcement, comprising the following steps:

[0006] S1, prepare a water glass solution with a concentration of 15-20wt%, add sodium secondary alkyl sulfonate, and select 98% sulfuric acid as an acidulant;

[0007] S2, first add 1 / 6 of the volume of the reactor into the reactor, and heat the water in the reactor; add materials during the heating process, and stir during the adding process until the reaction liquid reaches 2 / 3 of the volume of the reactor, and control the reaction time and maintain the reaction temperature; and the pH value of the reaction system in the reactor is controlled in a step-by-step manner;

[0008] S3, after stirring is completed, stop adding water glass, continue to add sulfuric acid solution to adjust the pH value of the reaction system to within the range of 4-6, stop adding sulfuric acid, and carry out precipitation reaction;

[0009] S4. After the precipitation reaction in S3 is completed, the reaction system is aged for 10-20 minutes while maintaining the stirring speed unchanged;

[0010] S5. The liquid in the reactor is filtered and washed with industrial water to obtain a filter cake, and the content of sodium sulfate in the filter cake is determined by the conductivity of the washing water, and the content of sodium sulfate in the final product is controlled to be less than 2%; the solid content of the filter cake is controlled at 20%-25%, and is directly sent to a pulping machine to form a thick slurry;

[0011] S6, sending the concentrated slurry obtained in S5 into a spray dryer using hot air from natural gas combustion as a heat source for drying to obtain granular silicon dioxide, and controlling the moisture content in the granular silicon dioxide to be 5%-7%;

[0012] S7. Then, the granular silicon dioxide obtained in S6 is fed into a briquetting machine to be made into granular silicon dioxide.

[0013] Furthermore, in the step S1, a surfactant, sodium secondary alkyl sulfonate, is added during the preparation of a water glass solution having a concentration of 15-20 wt %, so that the surfactant, sodium secondary alkyl sulfonate, is used as a reaction regulator.

[0014] Furthermore, in S2, the temperature of water in the reactor is controlled within the range of 85°C-95°C by steam heating; sulfuric acid solution and water glass solution are added to the reactor, the stirring speed is controlled within 100r / min-200r / min, and the reaction process is controlled within 60min, and the reaction temperature is maintained at 85°C-95°C.

[0015] Further, in S2, the reaction temperature is controlled in stages as follows:

[0016] The first stage: 0-20min, pH value 10-11;

[0017] The second stage: 20-40 minutes, pH value 8-9;

[0018] The third stage: 40-60 minutes, pH value 10-11.

[0019] The beneficial effects of the present invention are:

[0020] By adding the surfactant sodium secondary alkyl sulfonate as a reaction regulator in the initial stage of the reaction, the silanol group of the target product is controlled at 4-6OH / nm2 and the particle length (90% mass ratio) is controlled at more than 3mm after the reaction process is completed. DETAILED DESCRIPTION

[0021] In order to further understand the content, characteristics and effects of the present invention, the following embodiments are given to illustrate in detail.

[0022] Embodiment 1:

[0023] A method for preparing universal precipitated silica for rubber reinforcement comprises the following steps:

[0024] S1, prepare a water glass solution with a concentration of 15-20wt%, add sodium secondary alkyl sulfonate, and select 98% sulfuric acid as an acidulant;

[0025] S2, first add 1 / 6 of the volume of the reactor into the reactor, heat the water in the reactor, and control the temperature of the water in the reactor within 85°C by steam heating; and add sulfuric acid solution and water glass solution into the reactor, and stir the industrial water, sulfuric acid solution and water glass solution in the reactor during the addition process, control the stirring speed at 100r / min, and control the reaction process within 60min, until the reaction solution reaches 2 / 3 of the volume of the reactor, and stop, during the reaction, keep the reaction temperature at 85°C; and the pH value of the reaction system in the reactor is regulated in a step-by-step manner;

[0026] The first stage: 0-20min, pH value 10-11;

[0027] The second stage: 20-40 minutes, pH value 8-9;

[0028] The third stage: 40-60 minutes, pH value 10-11;

[0029] S3, after stirring is completed, stop adding water glass, continue to add sulfuric acid solution to adjust the pH value of the reaction system to within the range of 4-6, stop adding sulfuric acid, and carry out precipitation reaction;

[0030] S4. After the precipitation reaction in S3 is completed, the reaction system is aged for 10 min while maintaining the stirring speed unchanged;

[0031] S5. The liquid in the reactor is filtered and washed with industrial water to obtain a filter cake. The sodium sulfate content in the filter cake is determined by the conductivity of the washing water, and the sodium sulfate content of the final product is controlled to be less than 2%. The solid content of the filter cake is controlled at 20%-25%, and the filter cake is directly sent to a pulping machine to form a thick slurry.

[0032] S6, sending the concentrated slurry obtained in S5 into a spray dryer using hot air from natural gas combustion as a heat source for drying to obtain granular silicon dioxide, and controlling the moisture content in the granular silicon dioxide to be 5%-7%;

[0033] S7. Then, the granular silicon dioxide obtained in S6 is fed into a briquetting machine to be made into granular silicon dioxide.

[0034] Embodiment 2:

[0035] S1, prepare a water glass solution with a concentration of 15-20wt%, add sodium secondary alkyl sulfonate, and select 98% sulfuric acid as an acidulant;

[0036] S2, first add 1 / 6 of the volume of the reactor into the reactor, heat the water in the reactor, and control the temperature of the water in the reactor within 90°C by steam heating; and add sulfuric acid solution and water glass solution into the reactor, and stir the industrial water, sulfuric acid solution and water glass solution in the reactor during the addition process, control the stirring speed at 150r / min, and control the reaction process within 60min, until the reaction solution reaches 2 / 3 of the volume of the reactor, and during the reaction, keep the reaction temperature at 90°C; and the pH value of the reaction system in the reactor is regulated in a step-by-step manner;

[0037] The first stage: 0-20min, pH value 10-11;

[0038] The second stage: 20-40 minutes, pH value 8-9;

[0039] The third stage: 40-60 minutes, pH value 10-11;

[0040] S3, after stirring is completed, stop adding water glass, continue to add sulfuric acid solution to adjust the pH value of the reaction system to within the range of 4-6, stop adding sulfuric acid, and carry out precipitation reaction;

[0041] S4. After the precipitation reaction in S3 is completed, the reaction system is aged for 15 minutes while maintaining the stirring speed unchanged;

[0042] S5. The liquid in the reactor is filtered and washed with industrial water to obtain a filter cake. The sodium sulfate content in the filter cake is determined by the conductivity of the washing water, and the sodium sulfate content of the final product is controlled to be less than 2%. The solid content of the filter cake is controlled at 20%-25%, and the filter cake is directly sent to a pulping machine to form a thick slurry.

[0043] S6, sending the concentrated slurry obtained in S5 into a spray dryer using hot air from natural gas combustion as a heat source for drying to obtain granular silicon dioxide, and controlling the moisture content in the granular silicon dioxide to be 5%-7%;

[0044] S7. Then, the granular silicon dioxide obtained in S6 is fed into a briquetting machine to be made into granular silicon dioxide.

[0045] Embodiment three:

[0046] S1, prepare a water glass solution with a concentration of 15-20wt%, add sodium secondary alkyl sulfonate, and select 98% sulfuric acid as an acidulant;

[0047] S2, first add 1 / 6 of the volume of the reactor into the reactor, heat the water in the reactor, and control the temperature of the water in the reactor within 95°C by steam heating; and add sulfuric acid solution and water glass solution into the reactor, and stir the industrial water, sulfuric acid solution and water glass solution in the reactor during the addition process, control the stirring speed at 200r / min, and control the reaction process within 60min, until the reaction solution reaches 2 / 3 of the volume of the reactor and stops, and during the reaction, keep the reaction temperature at 95°C; and the pH value of the reaction system in the reactor is regulated in a step-by-step manner;

[0048] The first stage: 0-20min, pH value 10-11;

[0049] The second stage: 20-40 minutes, pH value 8-9;

[0050] The third stage: 40-60 minutes, pH value 10-11;

[0051] S3, after stirring is completed, stop adding water glass, continue to add sulfuric acid solution to adjust the pH value of the reaction system to within the range of 4-6, stop adding sulfuric acid, and carry out precipitation reaction;

[0052] S4. After the precipitation reaction in S3 is completed, the reaction system is aged for another 20 minutes while maintaining the stirring speed unchanged;

[0053] S5. The liquid in the reactor is filtered and washed with industrial water to obtain a filter cake. The sodium sulfate content in the filter cake is determined by the conductivity of the washing water, and the sodium sulfate content of the final product is controlled to be less than 2%. The solid content of the filter cake is controlled at 20%-25%, and the filter cake is directly sent to a pulping machine to form a thick slurry.

[0054] S6, sending the concentrated slurry obtained in S5 into a spray dryer using hot air from natural gas combustion as a heat source for drying to obtain granular silicon dioxide, and controlling the moisture content in the granular silicon dioxide to be 5%-7%;

[0055] S7. Then, the granular silicon dioxide obtained in S6 is fed into a briquetting machine to be made into granular silicon dioxide.

[0056] Table 1 Silicon dioxide of Examples 1 to 3

[0057]

[0058] Based on the above examples, it can be seen that the method of the present invention can achieve the preparation of BET at 1003m 2 / g-13m 2 / g; silanol group 4OH / nm 2 -6OH / nm2 ; Silicon dioxide content ≥95%-98%; Heating loss: 4.0%-8.0%; DBP oil absorption value: Silicon dioxide in the range of 1.5-2.0.

[0059] 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 by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing general precipitated silica for rubber reinforcement, characterized in that: The following steps are involved: S1, prepare a water glass solution with a concentration of 15-20wt%, add sodium secondary alkyl sulfonate, and select 98% sulfuric acid as an acidulant; S2, first add 1 / 6 of the volume of the reactor into the reactor, and heat the water in the reactor; add materials during the heating process, and stir during the adding process until the reaction liquid reaches 2 / 3 of the volume of the reactor, and control the reaction time and maintain the reaction temperature; and the pH value of the reaction system in the reactor is controlled in a step-by-step manner; S3, after stirring is completed, stop adding water glass, continue to add sulfuric acid solution to adjust the pH value of the reaction system to within the range of 4-6, stop adding sulfuric acid, and carry out precipitation reaction; S4. After the precipitation reaction in S3 is completed, the reaction system is aged for 10-20 minutes while maintaining the stirring speed unchanged; S5. The liquid in the reactor is filtered and washed with industrial water to obtain a filter cake, and the content of sodium sulfate in the filter cake is determined by the conductivity of the washing water, and the content of sodium sulfate in the final product is controlled to be less than 2%; the solid content of the filter cake is controlled at 20%-25%, and is directly sent to a pulping machine to form a thick slurry; S6, sending the concentrated slurry obtained in S5 into a spray dryer using hot air from natural gas combustion as a heat source for drying to obtain granular silicon dioxide, and controlling the moisture content of the granular silicon dioxide to be 5%-7%; S7. Then, the granular silicon dioxide obtained in S6 is fed into a briquetting machine to be made into granular silicon dioxide.

2. The method for preparing a general-purpose precipitated silica for rubber reinforcement according to claim 1, characterized in that: In the step S1, a surfactant, sodium secondary alkyl sulfonate, is added during the preparation of a water glass solution having a concentration of 15-20 wt %, so that the surfactant, sodium secondary alkyl sulfonate, is used as a reaction regulator.

3. The method for preparing a general-purpose precipitated silica for rubber reinforcement according to claim 1, characterized in that: In S2, the temperature of water in the reactor is controlled within the range of 85°C-95°C by steam heating; sulfuric acid solution and water glass solution are added to the reactor, the stirring speed is controlled within 100r / min-200r / min, and the reaction process is controlled within 60min, and the reaction temperature is maintained at 85°C-95°C.

4. The method for preparing a general-purpose precipitated silica for rubber reinforcement according to claim 1, characterized in that: In said S2, the reaction temperature is controlled in stages as follows: The first stage: 0-20min, pH value 10-11; The second stage: 20-40 minutes, pH value 8-9; The third stage: 40-60 minutes, pH value 10-11.

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