Production method of white carbon black with high specific surface area and high dispersion

Abstract

The invention relates to the technical field of white carbon black, and provides a production method of high-specific-surface-area high-dispersion white carbon black, which comprises the following steps: S1, adding an acid solution into a sodium silicate solution with the mass of 30-40% to adjust the pH value to 6-7, carrying out a first reaction, and aging to obtain a mixture A; s2, adding 20-30% by mass of a sodium silicate solution into the mixture A, adding an acid solution to adjust the pH value to 7.5-8.5, and carrying out a second reaction to obtain a mixture B; s3, adding the residual mass of the sodium silicate solution into the mixture B, adding an acid solution to adjust the pH value to 3.5-4.5, carrying out a third reaction, and carrying out post-treatment to obtain the white carbon black. According to the technical scheme, the problem that the specific surface area of the white carbon black in the related technology is relatively low is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of white carbon black, and in particular to a method for producing high-specific surface area and highly dispersed white carbon black. Background Art

[0002] As an important inorganic chemical product, silica has excellent properties such as high temperature resistance and electrical insulation. It is widely used in light industry and chemical industry, especially as a reinforcing filler in the rubber industry.

[0003] The production methods of silica include vapor phase method and precipitation method. The process of producing silica by vapor phase method is relatively complicated, with defects such as high cost and high equipment requirements. As a result, the price of silica produced by vapor phase method is relatively high and it is not widely used in actual applications. The precipitation method has the advantages of low cost and simple operation, and is favored by various industries. However, during the precipitation reaction, the parameters such as reaction conditions are not set reasonably, which hinders the improvement of the specific surface area of silica. It makes it difficult for the specific surface area of the produced silica to reach more than 200m² / g, limiting the further application of silica.

[0004] Therefore, a method for producing silica with a high specific surface area is needed. Summary of the Invention

[0005] The present invention provides a method for producing high-specific surface area and highly dispersed white carbon black, which solves the problem of low specific surface area of white carbon black in the related art.

[0006] The technical solutions of the present invention are as follows: The present invention provides a method for producing high-specific-surface-area and highly-dispersed white carbon black, comprising the following steps: S1. Acid solution is added to a 30% to 40% by mass sodium silicate solution to adjust the pH to 6 to 7 for a first reaction, followed by aging to obtain a mixture A; S2. After adding 20% to 30% by weight of sodium silicate solution to the mixture A, an acid solution was added to adjust the pH to 7.5 to 8.5 for a second reaction to obtain a mixture B; S3. After adding the remaining mass of the sodium silicate solution to the mixture B, an acid solution is added to adjust the pH to 3.5-4.5 for a third reaction, and post-processing is performed to obtain white carbon black.

[0007] As a further technical solution, the temperature of the first reaction is 70~90°C, for example, it can be 70°C, 74°C, 76°C, 78°C, 80°C, 86°C, 90°C, etc., preferably 70°C, 80°C, 90°C, and more preferably 80°C.

[0008] As a further technical solution, the time of the first reaction is 10 to 15 minutes, for example, it can be 10 minutes, 11 minutes, 13 minutes, 14 minutes, 15 minutes, etc., preferably 10 minutes, 12 minutes, 15 minutes, and more preferably 12 minutes.

[0009] As a further technical solution, the stirring speed of the first reaction is 120~170rpm, for example, it can be 120rpm, 135rpm, 145rpm, 150rpm, 170rpm, etc., preferably 120rpm, 150rpm, 170rpm, and more preferably 150rpm.

[0010] As a further technical solution, the aging time is 15 to 25 minutes.

[0011] As a further technical solution, the temperature of the second reaction is 70~95°C, for example, it can be 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, etc., preferably 70°C, 75°C, 80°C, 95°C.

[0012] As a further technical solution, the time of the second reaction is 10 to 15 minutes, for example, it can be 10 minutes, 12 minutes, 14 minutes, 15 minutes, etc., preferably 10 minutes, 14 minutes, 15 minutes.

[0013] As a further technical solution, the stirring speed of the second reaction is 120-170 rpm, for example, it can be 120 rpm, 125 rpm, 130 rpm, 140 rpm, 150 rpm, 170 rpm, etc.

[0014] As a further technical solution, the temperature of the third reaction is 80~95°C, for example, it can be 80°C, 82°C, 85°C, 90°C, 92°C, 95°C, etc., preferably 80°C, 90°C, 95°C, and more preferably 90°C.

[0015] As a further technical solution, the time of the third reaction is 20 to 40 min, for example, it can be 20 min, 24 min, 30 min, 34 min, 40 min, etc., preferably 20 min, 30 min, 40 min, and more preferably 30 min.

[0016] As a further technical solution, the stirring speed of the third reaction is 120~170rpm, for example, it can be 120rpm, 130rpm, 135rpm, 140rpm, 145rpm, 155rpm, 165rpm, 170rpm, etc.

[0017] As a further technical solution, the temperature of the first reaction is greater than the temperature of the second reaction.

[0018] In the preparation process of silica, on the basis of the temperature of the first reaction being 70-90° C. and the temperature of the second reaction being 70-95° C., the temperature of the first reaction is adjusted to be higher than the temperature of the second reaction, so that the molecules move smoothly during the reaction, which is conducive to the formation of smaller primary particles and the increase of the specific surface area of the final silica.

[0019] As a further technical solution, the stirring speed of the second reaction is lower than the stirring speed of the third reaction.

[0020] In the present invention, during the preparation of silica, the stirring speed of the second reaction is made lower than the stirring speed of the third reaction, so that the sodium silicate solution and the sulfuric acid solution are fully mixed and reacted, thereby promoting uniform precipitation and obtaining uniformly distributed silica particles with a high specific surface area, thereby avoiding the problem of uneven mixing of raw materials due to excessively slow stirring speed, insufficient reaction, and a reduction in the specific surface area of silica.

[0021] As a further technical solution, the stirring speed of the second reaction is 130-140 rpm, and the stirring speed of the third reaction is 145-155 rpm.

[0022] In the present invention, in the process of preparing white carbon black, especially when the stirring speed of the second reaction is 130-140 rpm and the stirring speed of the third reaction is 145-155 rpm, the specific surface area of the prepared white carbon black can reach 270 m 2 / g or above.

[0023] Different reaction temperatures and stirring speeds during the preparation of silica can lead to differences in the structure and properties of silica. Therefore, by controlling the stirring speed and reaction temperature within the ranges of the present invention, on the one hand, the reactants can be fully contacted, the uniformity of the reaction can be improved, the occurrence of side reactions can be reduced, and the aggravation of particle agglomeration can be avoided. On the other hand, it is conducive to the preparation of silica with a high specific surface area, thereby affecting its adsorption and dispersion properties, etc., broadening the application range of silica in fields such as rubber and ensuring that silica performs optimally during application.

[0024] As a further technical solution, the post-processing includes filtration, washing, and drying in sequence.

[0025] During the preparation of silica, post-treatment can separate the silica generated by the reaction from the reaction mixture and remove a large amount of soluble impurities and solvents, thereby improving the purity and stability of silica, and facilitating the subsequent processing and application of silica in various fields.

[0026] As a further technical solution, in step S1, step S2 and step S3, the acid solution independently includes a sulfuric acid solution.

[0027] As a further technical solution, in step S1, step S2 and step S3, the mass fraction of the sodium silicate solution is independently 10% to 15%; The mass fraction of the acid solution is independently 20% to 25%.

[0028] As a further technical solution, dinonylphenol is added during the third reaction.

[0029] As a further technical solution, the mass of the dinonylphenol is 5% to 8% of the total mass of the sodium silicate solutions in steps S1 to S3.

[0030] Since silica has a high specific surface area, it easily absorbs moisture, resulting in an abundant number of surface hydroxyl groups, which causes silica to easily agglomerate, affecting the further application effect of silica. In the prior art, organic siloxanes (such as hexamethyldisiloxane) or long-chain alkanol surfactants (such as dodecanol) are often used to treat silica to improve the dispersibility of silica. However, the improvement in the dispersion effect of silica is limited, and silica still has the problem of large particle size caused by easy agglomeration. Therefore, in the present invention, dinonylphenol is used to treat silica during the production of silica. Compared with the prior art, the particle size D50 of the silica after dinonylphenol treatment can be reduced to below 2μm, which greatly improves the easy agglomeration of silica. In addition, the silica prepared by the present invention has the characteristics of excellent dispersibility and high specific surface area.

[0031] The working principle and beneficial effects of the present invention are: In the present invention, the production method of high-specific surface area and highly dispersed white carbon black comprises first reacting 30% to 40% by mass of a sodium silicate solution with an acid solution, then adding 20% to 30% by mass of the sodium silicate solution for a second reaction, and finally adding the remaining mass of the sodium silicate solution for a third reaction. The white carbon black obtained by the three-step reaction has the characteristic of a higher specific surface area. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Figure 1 This is a particle size distribution diagram of white carbon black prepared in Example 10 of the present invention.

[0034] Figure 2 This is a particle size distribution diagram of white carbon black prepared in Example 11 of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] Example 1 The production method of high specific surface area and highly dispersed white carbon black comprises the following steps: S1. Add sulfuric acid solution to a 30% by mass sodium silicate solution to adjust the pH to 6, mix at 70° C. and a stirring speed of 120 rpm, react for 15 minutes, and age for 25 minutes to obtain a mixture A; S2. After adding 30% by weight of sodium silicate solution to mixture A, sulfuric acid solution was added to adjust the pH to 7.5, and the mixture was mixed at a temperature of 75° C. and a stirring speed of 120 rpm, and reacted for 15 minutes to obtain mixture B; S3. After adding the remaining mass of sodium silicate solution to mixture B, sulfuric acid solution was added to adjust the pH to 3.5, the mixture was mixed at a temperature of 80° C. and a stirring speed of 120 rpm, reacted for 40 minutes, filtered, and the filter cake was rinsed with distilled water until the pH reached 6.5. The filter cake was placed in an oven at 110° C. and dried for 20 hours to obtain white carbon black; wherein the mass fraction of the sodium silicate solution is 20%, and the mass fraction of the sulfuric acid solution is 12%.

[0037] Example 2 The production method of high specific surface area and highly dispersed white carbon black comprises the following steps: S1. Add sulfuric acid solution to a 40% by mass sodium silicate solution to adjust the pH to 7, mix at 90° C. and a stirring speed of 170 rpm, react for 10 minutes, and age for 15 minutes to obtain a mixture A; S2. After adding 20% by weight of sodium silicate solution to mixture A, sulfuric acid solution was added to adjust the pH to 8.5, and the mixture was mixed at a temperature of 95° C. and a stirring speed of 170 rpm for 10 minutes to obtain mixture B; S3. After adding the remaining mass of sodium silicate solution to mixture B, sulfuric acid solution was added to adjust the pH to 4.5, the mixture was mixed at a temperature of 95° C. and a stirring speed of 170 rpm, reacted for 20 minutes, filtered, and the filter cake was rinsed with distilled water until the pH reached 7. The filter cake was placed in an oven at 110° C. and dried for 20 hours to obtain white carbon black; wherein the mass fraction of the sodium silicate solution is 25%, and the mass fraction of the sulfuric acid solution is 15%.

[0038] Example 3 The production method of high specific surface area and highly dispersed white carbon black comprises the following steps: S1. Add sulfuric acid solution to a 35% by mass sodium silicate solution to adjust the pH to 6.5, mix at 80° C. and a stirring speed of 150 rpm, react for 12 minutes, and age for 20 minutes to obtain a mixture A; S2. After adding 25% by weight of sodium silicate solution to mixture A, sulfuric acid solution was added to adjust the pH to 8, and the mixture was mixed at a temperature of 80° C. and a stirring speed of 125 rpm for 14 minutes to obtain mixture B; S3. After adding the remaining mass of sodium silicate solution to mixture B, sulfuric acid solution was added to adjust the pH to 4, the mixture was mixed at a temperature of 90° C. and a stirring speed of 125 rpm, reacted for 30 minutes, filtered, and the filter cake was rinsed with distilled water until the pH reached 7. The filter cake was placed in an oven at 110° C. and dried for 20 hours to obtain white carbon black; wherein the mass fraction of the sodium silicate solution is 22%, and the mass fraction of the sulfuric acid solution is 14wt%.

[0039] Example 4 The only difference between this embodiment and embodiment 3 is that the temperature in step S1 is 70°C.

[0040] Example 5 The only difference between this embodiment and embodiment 3 is that the temperature in step S2 is 70°C.

[0041] Example 6 The only difference between this embodiment and embodiment 5 is that the stirring speed in step S3 is 165 rpm.

[0042] Example 7 The only difference between this embodiment and embodiment 5 is that the stirring speed in step S3 is 145 rpm.

[0043] Example 8 The only difference between this embodiment and embodiment 5 is that the stirring speed in step S3 is 155 rpm.

[0044] Example 9 The only difference between this embodiment and embodiment 8 is that the stirring speed in step S2 is 150 rpm.

[0045] Example 10 The only difference between this embodiment and embodiment 8 is that the stirring speed in step S2 is 130 rpm.

[0046] Example 11 The only difference between this embodiment and embodiment 8 is that the stirring speed in step S2 is 140 rpm.

[0047] Example 12 The production method of high specific surface area and highly dispersed white carbon black comprises the following steps: S1. Add sulfuric acid solution to a 35% by mass sodium silicate solution to adjust the pH to 6.5, mix at 80° C. and a stirring speed of 150 rpm, react for 12 minutes, and age for 20 minutes to obtain a mixture A; S2. After adding 25% by weight of sodium silicate solution to mixture A, sulfuric acid solution was added to adjust the pH to 8, and the mixture was mixed at a temperature of 70° C. and a stirring speed of 140 rpm for 14 minutes to obtain mixture B; S3. After adding the remaining mass of sodium silicate solution and dinonylphenol to mixture B, sulfuric acid solution was added to adjust the pH to 4, the mixture was mixed at a temperature of 90° C. and a stirring speed of 155 rpm, reacted for 30 minutes, filtered, and the filter cake was rinsed with distilled water until the pH reached 7. The filter cake was placed in an oven at 110° C. and dried for 20 hours to obtain white carbon black; wherein the mass fraction of the sodium silicate solution is 22%, the mass fraction of the sulfuric acid solution is 14wt%; the mass of the dinonylphenol is 5% of the total mass of the sodium silicate solutions in steps S1 to S3; and the dinonylphenol is 2,3-dinonylphenol.

[0048] Example 13 The only difference between this embodiment and embodiment 12 is that the mass of dinonylphenol is 8% of the total mass of the sodium silicate solutions in steps S1 to S3.

[0049] Example 14 The only difference between this example and Example 12 is that dinonylphenol is replaced by hexamethyldisiloxane.

[0050] Example 15 The only difference between this example and Example 12 is that dinonylphenol is replaced by 1-dodecanol.

[0051] Example 16 The production method of high specific surface area and highly dispersed white carbon black comprises the following steps: S1. Add sulfuric acid solution to a 40% by mass sodium silicate solution to adjust the pH to 6, mix at 70° C. and a stirring speed of 120 rpm, react for 15 minutes, and age for 25 minutes to obtain a mixture A; S2. After adding 20% by weight of sodium silicate solution to mixture A, sulfuric acid solution was added to adjust the pH to 7.5, and the mixture was mixed at a temperature of 75° C. and a stirring speed of 120 rpm for 15 minutes to obtain mixture B; S3. After adding the remaining mass of sodium silicate solution to mixture B, sulfuric acid solution was added to adjust the pH to 3.5, the mixture was mixed at a temperature of 80° C. and a stirring speed of 120 rpm, reacted for 40 minutes, filtered, and the filter cake was rinsed with distilled water until the pH reached 6.5. The filter cake was placed in an oven at 110° C. and dried for 20 hours to obtain white carbon black; wherein the mass fraction of the sodium silicate solution is 20%, and the mass fraction of the sulfuric acid solution is 12%.

[0052] Comparative Example 1 The production method of high specific surface area and highly dispersed white carbon black comprises the following steps: S1. Add sulfuric acid solution to a 35% by mass sodium silicate solution to adjust the pH to 6.5, mix at 80° C. and a stirring speed of 150 rpm, react for 12 minutes, and age for 20 minutes to obtain a mixture A; S2. After adding the remaining mass of sodium silicate solution to mixture A, sulfuric acid solution was added to adjust the pH to 4, the mixture was mixed at a temperature of 90° C. and a stirring speed of 125 rpm, reacted for 30 minutes, filtered, and the filter cake was rinsed with distilled water until the pH reached 7. The filter cake was placed in an oven at 110° C. and dried for 20 hours to obtain white carbon black; wherein the mass fraction of the sodium silicate solution was 22%, and the mass fraction of the sulfuric acid solution was 14 wt%.

[0053] Comparative Example 2 The production method of high specific surface area and highly dispersed white carbon black comprises the following steps: S1. Add sulfuric acid solution to a 20% by mass sodium silicate solution to adjust the pH to 6, mix at 70° C. and a stirring speed of 120 rpm, react for 15 minutes, and age for 25 minutes to obtain a mixture A; S2. After adding 40% by weight of sodium silicate solution to mixture A, sulfuric acid solution was added to adjust the pH to 7.5, and the mixture was mixed at a temperature of 75° C. and a stirring speed of 120 rpm, and reacted for 15 minutes to obtain mixture B; S3. After adding the remaining mass of sodium silicate solution to mixture B, sulfuric acid solution was added to adjust the pH to 3.5, the mixture was mixed at a temperature of 80° C. and a stirring speed of 120 rpm, reacted for 40 minutes, filtered, and the filter cake was rinsed with distilled water until the pH reached 6.5. The filter cake was placed in an oven at 110° C. and dried for 20 hours to obtain white carbon black; wherein the mass fraction of the sodium silicate solution is 20%, and the mass fraction of the sulfuric acid solution is 12%.

[0054] Comparative Example 3 The production method of high specific surface area and highly dispersed white carbon black comprises the following steps: S1. Add sulfuric acid solution to 50% by mass of sodium silicate solution to adjust the pH to 6, mix at 70° C. and stirring at 120 rpm, react for 15 minutes, and age for 25 minutes to obtain mixture A; S2. After adding 10% by weight of sodium silicate solution to mixture A, sulfuric acid solution was added to adjust the pH to 7.5, and the mixture was mixed at a temperature of 75° C. and a stirring speed of 120 rpm, and reacted for 15 minutes to obtain mixture B; S3. After adding the remaining mass of sodium silicate solution to mixture B, sulfuric acid solution was added to adjust the pH to 3.5, the mixture was mixed at a temperature of 80° C. and a stirring speed of 120 rpm, reacted for 40 minutes, filtered, and the filter cake was rinsed with distilled water until the pH reached 6.5. The filter cake was placed in an oven at 110° C. and dried for 20 hours to obtain white carbon black; wherein the mass fraction of the sodium silicate solution is 20%, and the mass fraction of the sulfuric acid solution is 12%.

[0055] Experimental Example 1 The CTAB specific surface area of the white carbon black prepared in Examples 1 to 11, Example 16, and Comparative Examples 1 to 3 was tested according to the standard GB / T 23656-2016 “Determination of the specific surface area of precipitated hydrated silica in rubber compounds - CTAB method”. The results are shown in Table 1 below.

[0056] Table 1 Specific surface area test results

[0057] Compared with Comparative Examples 1 to 3, the specific surface area of the white carbon black prepared in Examples 1 to 11 and Example 16 is higher, indicating that the method for preparing white carbon black in three steps of the present invention and controlling the amount of sodium silicate solution added in each step can increase the specific surface area of the white carbon black, and the specific surface area of the white carbon black can be further increased by adjusting the reaction conditions such as the reaction temperature and stirring speed during the production process.

[0058] Experimental Example 2 The dispersibility of the silica prepared in Examples 10-15 was tested: The silica was mixed with water for 5 minutes to obtain a mixed solution. The average particle size of the silica particles in the aqueous phase was measured using a wet laser particle size analyzer (HELOS-SUCELL). The average particle size is the particle size at 50% of the cumulative distribution, recorded as D50. The smaller the D50 particle size, the better the dispersibility of the silica. The results are shown in Table 2 below.

[0059] Table 2 Dispersion test results

[0060] The particle size distribution of the white carbon black obtained in Example 10 is as follows: Figure 1As shown, the particle size distribution of the white carbon black obtained in Example 11 is as shown in FIG. Figure 2 shown.

[0061] Compared with Examples 10-11 and Examples 14-15, the particle size D50 of the silica prepared in Examples 12-13 is smaller, indicating that the treatment of silica with dinonylphenol improves the dispersibility of silica and reduces the agglomeration of silica particles.

[0062] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for producing high specific surface area and highly dispersed white carbon black, characterized in that: The following steps are involved: S1. Acid solution is added to a 30% to 40% by mass sodium silicate solution to adjust the pH to 6 to 7 for a first reaction, followed by aging to obtain a mixture A; S2. After adding 20% to 30% by weight of sodium silicate solution to the mixture A, an acid solution was added to adjust the pH to 7.5 to 8.5 for a second reaction to obtain a mixture B; S3, after adding the remaining mass of sodium silicate solution to the mixture B, adding acid to adjust the pH to 3.5-4.5 for a third reaction, and post-treating to obtain white carbon black; The first reaction temperature is 70-90°C, the time is 10-15 minutes, and the stirring speed is 120-170 rpm; The second reaction temperature is 70-95°C, the time is 10-15 minutes, and the stirring speed is 130-140 rpm; The temperature of the third reaction is 80-95°C, the time is 20-40 minutes, and the stirring speed is 145-155 rpm; The temperature of the first reaction is higher than the temperature of the second reaction.

2. The method for producing high specific surface area and highly dispersed white carbon black according to claim 1, characterized in that: The aging time is 15 to 25 minutes.

3. The method for producing high specific surface area and highly dispersed white carbon black according to claim 1, characterized in that: The post-processing includes filtering, washing and drying in sequence.

4. The method for producing high specific surface area and highly dispersed white carbon black according to claim 1, characterized in that: In step S1, step S2 and step S3, the acid solution independently includes a sulfuric acid solution.

5. The method for producing high specific surface area and highly dispersed white carbon black according to claim 1, characterized in that: In step S1, step S2 and step S3, the mass fraction of the sodium silicate solution is independently 10% to 15%; The mass fraction of the acid solution is independently 20% to 25%.

6. The method for producing high specific surface area and highly dispersed white carbon black according to claim 1, characterized in that: The third reaction is carried out by adding dinonylphenol.

7. The method for producing high specific surface area and highly dispersed white carbon black according to claim 6, characterized in that: The mass of the dinonylphenol is 5% to 8% of the total mass of the sodium silicate solutions in steps S1 to S3.

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