Preparation method of high specific surface large pore volume white carbon black

Abstract

The application discloses a preparation method of white carbon black with high specific surface and large pore volume, and comprises the following steps: (1) adding water and dilute sulfuric acid solution into a reaction kettle, stirring, uniformly mixing the water and the dilute sulfuric acid, and heating; (2) continuously adding dilute sulfuric acid and sodium silicate solution into the reaction kettle to react; (3) adding sodium hydroxide solution into the reaction kettle until the solution in the reaction kettle turns into light blue; (4) adding ammonia water into the reaction kettle, adjusting the pH value of the solution, carrying out gel reaction, and then dispersing the gel; (5) carrying out solid-liquid separation, deionized water washing, beating and drying to obtain the white carbon black product. In the application, the ammonia water is added into the light blue silica sol system, NH4 + will become gas and leave the silica gel inside, and a large number of fine pores are left inside, so that the white carbon black has the characteristics of large pore volume.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of white carbon black preparation, and particularly relates to a preparation method of white carbon black with high specific surface and large pore volume. BACKGROUND

[0002] White carbon black is an amorphous white powder, and its main component is silicon dioxide, and its chemical formula is SiO2·nH2O. According to different production processes, white carbon black is divided into two types of fumed white carbon black and precipitated white carbon black. White carbon black is also known as industrial MSG, and is widely used in tires, soles, silicone rubber, coatings and plastics as a filler and adsorbent.

[0003] Since the fumed white carbon black has a large specific surface area and a porous structure, it has strong adsorption, and therefore can obtain a large loading capacity, increase the interfacial concentration in the reaction system, accelerate the reaction speed, and prolong the service life of the catalyst. The fumed white carbon black mainly serves the purposes of reducing cost, improving the mechanical strength of the catalyst, and increasing the activity of the catalyst.

[0004] The fumed white carbon black is mainly prepared by hydrolysis of chlorosilane and hydrogen and oxygen at a high temperature of 1800 DEG C to generate fumed silica particles, mixing the fumed silica with air to form a sol, and then gathering the sol through a gatherer to generate large particles, and then collecting the large particles through a cyclone to obtain the finished product.

[0005] However, the fumed white carbon black has problems of complex production process, high price of chlorosilane, and low yield. The specific surface area and pore volume of the precipitated white carbon black are lower than those of the fumed white carbon black, thereby limiting the use of the precipitated white carbon black in high-end application fields such as catalyst carriers. SUMMARY

[0006] To solve the problems in the background, the application provides a preparation method of white carbon black with high specific surface and large pore volume, which has the characteristics of simple production process, low raw material cost, and simple production equipment.

[0007] To achieve the above-mentioned purposes, the application provides the following technical scheme: a preparation method of white carbon black with high specific surface and large pore volume, comprising the following steps:

[0008] (1) adding water and dilute sulfuric acid solution into a reaction kettle, then starting the stirring system of the reaction kettle, mixing the water and dilute sulfuric acid uniformly, and heating the liquid in the reaction kettle;

[0009] (2) continuously adding dilute sulfuric acid and sodium silicate solution into the reaction kettle to react, the reaction time is 30-60 min, after the dropping of the reaction material is completed, the stirring is continued for 20-30 min;

[0010] (3) adding sodium hydroxide solution into the reactor until the solution in the reactor becomes light blue, and stopping adding sodium hydroxide solution;

[0011] (4) adding ammonia water into the reactor to adjust the pH value of the solution to 8.0-10.0, then stopping stirring, and allowing the gel to react for 30-60 min, and then dispersing the gel;

[0012] (5) performing solid-liquid separation, deionized water washing, beating-up and drying on the solution obtained in step (4) to obtain the ultra-high specific surface white carbon black product.

[0013] Further in the application, in step (1), the concentration of the dilute sulfuric acid solution is 0.5-2 mol / L.

[0014] Further in the application, in step (1), the pH value of the mixed liquid is 1-3.

[0015] Further in the application, in step (1), the temperature is raised to 40-60℃.

[0016] Further in the application, in step (2), the concentration of the sodium silicate solution is 1.0-2.5 mol / L.

[0017] Further in the application, in step (2), the pH value in the reactor during the reaction is 1-3.

[0018] Further in the application, in step (3), the concentration of the sodium hydroxide is 1.0-5.0 mol / L.

[0019] Further in the application, in step (4), after the gel is dispersed, the temperature is raised to 80-95℃, and then aging is performed for 10-30 min.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] 1. In the application, sodium silicate solution is added into the reactor for reaction, and the pH value in the reactor is controlled to be 1-3 during the reaction, so that the sodium silicate is rapidly hydrolyzed to form silicate ions under the acidic condition, and the silicate ions are condensed with each other to form colorless and transparent silica sol;

[0022] 2. In steps (1) and (2) of the application, the pH value in the reactor is controlled to be 1-3 to keep the sol in a stable state, so that the solid content of the system can be increased by increasing the flow of the reactant and prolonging the reaction time, thereby improving the production efficiency of the product;

[0023] 3、The present application adds ammonia water into the light blue silica sol system, because the silicic acid aggregate has a negative charge, under the action of static electricity, the silicic acid aggregate can form an ionic bond with NH4+, which uniformly brings a large amount of NH4+ into the sol system, and in the subsequent gel process, NH4+ will be left in the silica gel + Fixed in the silica gel, NH4+ will become gas and leave the inside of the silica gel during the subsequent drying process, and a large number of fine pores are left inside, forming complex internal channels, so that the white carbon black has the characteristics of large pore volume. + Fixed in the silica gel, NH4+ will become gas and leave the inside of the silica gel during the subsequent drying process, and a large number of fine pores are left inside, forming complex internal channels, so that the white carbon black has the characteristics of large pore volume. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0025] Embodiment 1

[0026] The present application provides the following technical solutions: a preparation method of high specific surface large pore volume white carbon black, comprising the following steps:

[0027] (1) 10L of water and dilute sulfuric acid solution are added to a 30L reaction kettle, the concentration of the dilute sulfuric acid solution is 0.5mol / L, then the stirring system of the reaction kettle is started, the water and the dilute sulfuric acid are mixed uniformly, the pH value of the liquid is controlled at 2.5, and the liquid in the kettle is heated to 60℃;

[0028] (2) 0.5mol / L dilute sulfuric acid and 1.0mol / L sodium silicate solution are continuously added to the reaction kettle for reaction, the pH value in the kettle is controlled at 2.5 during the reaction process, the reaction time is 60min, after the dropping of the reactants is completed, the stirring reaction is continued for 30min;

[0029] (3) 1mol / L sodium hydroxide solution is added to the reaction kettle until the solution in the reaction kettle becomes light blue, and the addition of sodium hydroxide solution is stopped;

[0030] (4) Ammonia water is added to the reaction kettle to adjust the pH value of the solution to 8.0, then the stirring is stopped, the gel reaction is carried out for 30min, then the gel is dispersed, heated to 90℃, and aged for 20min;

[0031] (5) The solution obtained in step (4) is subjected to solid-liquid separation, deionized water washing, beating and drying to obtain an ultra-high specific surface white carbon black product.

[0032] Embodiment 2

[0033] A preparation method of high specific surface large pore volume white carbon black, comprising the following steps:

[0034] (1), in 30L reactor is added 10L water and dilute sulfuric acid solution, the concentration of dilute sulfuric acid solution is 0.5mol / L, then start the stirring system of reactor, mix water and dilute sulfuric acid uniformly, the pH value of liquid is controlled at 2.5, and the liquid in the kettle is heated, and the temperature is raised to 40 DEG C;

[0035] (2), continuously add 0.5mol / L dilute sulfuric acid and 1.0mol / L sodium silicate solution to the reactor for reaction, the pH value in the reactor is controlled to 2.5 during the reaction process, the reaction time is 60 min, after the dropping of reactant is completed, continue to stir for 30 min;

[0036] (3), 1mol / L sodium hydroxide solution is added to the reactor until the solution in the reactor turns light blue, and the addition of sodium hydroxide solution is stopped;

[0037] (4), ammonia is added to the reactor to adjust the pH value of the solution to 8.0, then stop stirring, gel reaction for 30 min, then disperse the gel, heat to 90 DEG C, and age for 20 min;

[0038] (5), the solution obtained in step (4) is subjected to solid-liquid separation, deionized water washing, beating and drying to obtain an ultra-high specific surface white carbon black product.

[0039] Example 3

[0040] A preparation method of high specific surface large pore volume white carbon black, comprising the following steps:

[0041] (1), in 30L reactor is added 10L water and dilute sulfuric acid solution, the concentration of dilute sulfuric acid solution is 0.5mol / L, then start the stirring system of reactor, mix water and dilute sulfuric acid uniformly, the pH value of liquid is controlled at 2.5, and the liquid in the kettle is heated, and the temperature is raised to 40 DEG C;

[0042] (2), continuously add 0.5mol / L dilute sulfuric acid and 1.0mol / L sodium silicate solution to the reactor for reaction, the pH value in the reactor is controlled to 2.5 during the reaction process, the reaction time is 60 min, after the dropping of reactant is completed, continue to stir for 30 min;

[0043] (3), 1mol / L sodium hydroxide solution is added to the reactor until the solution in the reactor turns light blue, and the addition of sodium hydroxide solution is stopped;

[0044] (4), ammonia is added to the reactor to adjust the pH value of the solution to 8.0, then stop stirring, gel reaction for 30 min, then disperse the gel, heat to 80 DEG C, and age for 20 min.

[0045] (5) The solution obtained in step (4) is subjected to solid-liquid separation, deionized water washing, beating and drying to obtain the ultra-high specific surface white carbon black product.

[0046] Comparative Example 1

[0047] comprising the following steps:

[0048] (1) 10 L of water and a dilute sulfuric acid solution with a concentration of 0.5 mol / L are added to a 30 L reaction kettle, then the stirring system of the reaction kettle is started, the water and the dilute sulfuric acid are mixed uniformly, the pH value of the liquid is controlled at 2.5, and the liquid in the kettle is heated to 60°C;

[0049] (2) 0.5 mol / L dilute sulfuric acid and 1.0 mol / L sodium silicate solution are continuously added to the reaction kettle for reaction, the pH value in the kettle is controlled at 2.5 during the reaction process, the reaction time is 60 min, and after the dropping of the reactants is completed, the stirring reaction is continued for 30 min;

[0050] (3) 1 mol / L sodium hydroxide solution is added to the reaction kettle until the solution in the reaction kettle turns light blue, and the addition of sodium hydroxide solution is stopped;

[0051] (4) Sodium hydroxide solution is added to the reaction kettle to adjust the pH value of the solution to 8.0, then the stirring is stopped, the gel reaction is carried out for 30 min, then the gel is dispersed, the temperature is raised to 90°C, and aging is carried out for 20 min;

[0052] (5) The solution obtained in step (4) is subjected to solid-liquid separation, deionized water washing, beating and drying to obtain the ultra-high specific surface white carbon black product.

[0053] The detection results of the white carbon black prepared in Examples 1-3 and Comparative Example 1 are as follows:

[0054] Test item Example 1 Example 2 Example 3 Comparative Example 1 BET(m 2 / g) 348 420 436 225 Pore volume (mL / g) 2.1 2.4 2.3 1.6

[0055] As can be seen from the above table, adjusting the reaction temperature and using ammonia water can significantly increase the specific surface area and pore volume of the white carbon black.

[0056] In summary, the present application adds sodium silicate solution into the reaction kettle for reaction, and controls the pH value in the kettle to be 1-3 during the reaction process. The sodium silicate is rapidly hydrolyzed to form silicate ions under the acidic condition, and the silicate ions are condensed with each other, so that the colorless and transparent silica sol can be formed. In the step (1) and the step (2), the pH value in the reaction kettle is controlled to be 1-3, so that the sol is in a stable state. Therefore, the solid content of the system can be increased by increasing the flow of the reactant and prolonging the reaction time, so that the production efficiency of the product is improved. The ammonia water is added into the light blue silica sol system. Since the silicic acid aggregate has a negative charge, the silicic acid aggregate can be combined with NH4 + under the action of static electricity, so that the ion bond is formed. A large amount of NH4 + is uniformly brought into the sol system, and in the subsequent gel process, NH4 + is fixed in the silica gel. In the subsequent drying process, NH4 + becomes gas and leaves the inside of the silica gel, and a large number of fine pores are left inside, so that the complex internal channels are formed, so that the white carbon black has the characteristics of large pore volume.

[0057] Finally, it should be pointed out that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the present application is described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing high specific surface large pore volume white carbon black, characterized in that, The method comprises the following steps: (1) adding water and dilute sulfuric acid solution into a reaction kettle, then starting the stirring system of the reaction kettle, mixing the water and dilute sulfuric acid uniformly, and heating the liquid in the reaction kettle; (2) continuously adding dilute sulfuric acid and sodium silicate solution into the reaction kettle for reaction, the concentration of the sodium silicate solution is 1.0-2.5 mol / L, the reaction time is 30-60 min, after the dropping of the reactants is completed, the stirring reaction is continued for 20-30 min, and the pH value in the reaction kettle during the reaction is 1-3; under the acidic condition, the sodium silicate is rapidly hydrolyzed to form silicate ions, and the silicate ions are condensed with each other, so that colorless and transparent silica sol can be formed; (3) adding sodium hydroxide solution into the reaction kettle until the solution in the reaction kettle becomes light blue, and then stopping the addition of the sodium hydroxide solution; (4) adding ammonia water into the reaction kettle to adjust the pH value of the solution to 8.0-10.0, then stopping the stirring, and allowing the gel to react for 30-60 min, and then dispersing the gel; (5) performing solid-liquid separation, deionized water washing, beating and drying on the solution obtained in the step (4) to obtain the ultra-high specific surface white carbon black product. Ammonia is added into the light blue silica sol system. Because the silicic acid aggregate has a negative charge, under the action of static electricity, the silicic acid aggregate can form an ionic bond with NH4+, uniformly bringing a large amount of NH4+ into the sol system, and in the subsequent gel process, NH4+ + Fixed in the silica gel, NH4 + Will become a gas leaving the inside of the silica gel, and leave a large number of fine pores inside, forming a complex internal channel, so that the white carbon black has the characteristics of large pore volume.

2. The method for preparing high specific surface large pore volume white carbon black according to claim 1, characterized in that: In the step (1), the concentration of the dilute sulfuric acid solution is 0.5-2 mol / L.

3. The method according to claim 1, wherein the method is characterized by: In the step (1), the pH value of the mixed liquid is 1-3.

4. The method according to claim 1, wherein the method is characterized by: In the step (1), the temperature is raised to 40-60℃.

5. The method according to claim 1, wherein the method is characterized by: In the step (3), the concentration of the sodium hydroxide is 1.0-5.0 mol / L.

6. The method for preparing high specific surface large pore volume white carbon black according to claim 1, characterized in that: In the step (4), after the gel is dispersed, the temperature is raised to 80-95℃, and then aging is performed for 10-30 min.