A production process to improve the conductivity of carbon black

Abstract

This invention relates to the field of carbon black technology, and more particularly to a production process for improving the conductivity of carbon black. The process includes: first, carbon black is activated with carbon dioxide, then treated with nitric acid to obtain a porous carbon black material. This porous material is then treated with a mixed amino acid solution to obtain a carbon black material loaded with a mixed amino acid adsorption layer. Next, silver nitrate solution is added, and the mixture is stirred and mixed. Then, sodium borohydride solution is added dropwise, controlling the reaction temperature and pH. After the reaction is complete, the mixture is filtered, washed, and dried to obtain a highly conductive carbon black product. Using this production process can significantly improve the conductivity of carbon black.

Description

Technical Field

[0001] This invention relates to the field of carbon black technology, and in particular to a production process for improving the conductivity of carbon black. Background Technology

[0002] Carbon black is an amorphous form of carbon with various properties such as dispersion, adsorption, and conductivity. Based on these properties, it is widely used in environmental protection, chemical engineering, food, and pharmaceuticals. In the battery and energy sector, carbon black is commonly used as an additive to improve the conductivity of electrode materials. However, existing carbon black has poor conductivity, affecting the performance of batteries or electrode materials. Therefore, it is necessary to develop a production process to improve the conductivity of carbon black. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a production process for improving the conductivity of carbon black, which can be used to obtain carbon black products with high conductivity, in order to address the shortcomings of the prior art.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0005] A production process for improving the conductivity of carbon black, the production process comprising the following steps:

[0006] (1) Take carbon black, first pass nitrogen gas through it for preheating treatment, then pass carbon dioxide through it for activation treatment. After the activation treatment is completed, pass nitrogen gas through it again to cool to room temperature, wash and dry it to obtain carbon black material with pores for later use.

[0007] (2) Take the carbon black material after pore formation as described in step (1), add nitric acid and heat and stir. After the reaction is completed, wash until neutral, filter and dry to obtain porous carbon black material for later use.

[0008] (3) Take the porous carbon black material described in step (2), add a mixed amino acid solution, adjust the pH, heat, ultrasonically disperse, filter, and dry to obtain carbon black material loaded with a mixed amino acid adsorption layer for later use;

[0009] (4) Take the carbon black material loaded with the mixed amino acid adsorption layer in step (3), add deionized water and stir. Add silver nitrate solution to the carbon black liquid obtained, stir and mix well, then add sodium borohydride solution dropwise and continue stirring. Control the pH and reaction temperature. After the reaction is completed, filter, wash and dry to obtain a carbon black product with high conductivity.

[0010] As an improved technical solution, in step (1), the carbon black material is heated to 300-450℃ at a heating rate of 5-10℃ / min during the preheating treatment.

[0011] As an improved technical solution, in step (1), the flow rate of carbon dioxide during activation is 20-60 mL / min, the temperature of activation is controlled at 700-900℃, and the activation time is controlled at 1-2 h.

[0012] As an improved technical solution, in step (2), the carbon black material after pore formation is mixed with the nitric acid at a mass ratio of 1:4-8, and the concentration of the nitric acid is 40-50wt%.

[0013] As an improved technical solution, in step (2), the temperature is heated to 100-120℃ and the reaction time is controlled to be 2-4h.

[0014] As an improved technical solution, in step (3), the porous carbon black material is mixed with the mixed amino acid solution at a mass-volume ratio of 1:1.2-1.8; the mixed amino acid solution is a solution made by mixing lysine, phenylalanine and purified water at a mass-volume ratio of 2-4 mg:1-3 mg:5-15 mL.

[0015] As an improved technical solution, in step (3), the pH is adjusted to 7-8, the temperature is heated to 50-70℃, the ultrasonic dispersion power is 400-500w, and the ultrasonic dispersion time is 15-35min.

[0016] As an improved technical solution, in step (4), the carbon black material loaded with the mixed amino acid adsorption layer is mixed with the deionized water at a mass-volume ratio of 1:1.2-1.5.

[0017] As an improved technical solution, in step (4), the mass ratio of the carbon black material loaded with the mixed amino acid adsorption layer to the silver nitrate in the silver nitrate solution is 2-3.2:1, and the concentration of the silver nitrate solution and the concentration of the sodium borohydride are both 0.08-0.18 mol / L.

[0018] As an improved technical solution, in step (4), the pH is controlled at 8-10 and the reaction temperature is controlled at 25-45℃.

[0019] After adopting the above technical solution, the beneficial effects of the present invention are:

[0020] This invention first activates carbon black with carbon dioxide, forming abundant micropores and mesopores within the carbon black particles, significantly increasing its specific surface area and porosity. This provides more active sites and space for the introduction of functional groups, amino acid adsorption, and metal particle loading in subsequent steps. Then, it undergoes nitric acid oxidation treatment, introducing oxygen-containing functional groups such as carboxyl (-COOH), hydroxyl (-OH), and carbonyl (C=O) groups, improving the hydrophilicity and chemical activity of the carbon black surface and enhancing its interaction with subsequent amino acid solutions and metal ions. A mixed amino acid adsorption layer is then constructed. This increases the dispersibility of carbon black in aqueous solution, preventing particle agglomeration. Furthermore, the amino (-NH2) and carboxyl (-COOH) functional groups in the amino acid molecules act as coordinating groups, interacting with silver ions (Ag) in subsequent steps. + Coordination occurs, increasing the adsorption capacity and binding stability of silver ions on the carbon black surface; then, by controlling the reaction conditions, silver nitrate provides Ag... + Sodium borohydride (NaBH4) acts as a strong reducing agent to reduce Ag. + The carbon black is reduced to metallic silver (Ag) nanoparticles; the amino acid adsorption layer on the carbon black surface captures Ag through coordination. + This process ensures that silver nanoparticles are uniformly loaded onto the surface and pores of carbon black. Because the loaded silver nanoparticles can form conductive pathways between carbon black particles, they reduce the contact resistance of the carbon black and significantly improve its overall conductivity. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Example 1

[0022] A production process for improving the conductivity of carbon black includes the following steps:

[0023] (1) Take 100 mg of carbon black with a particle size of 30-40 nm (specific surface area of ​​80-130 m²). 2 The carbon black material was first preheated by purging with nitrogen (heated to 300℃ at a heating rate of 5℃ / min), and then activated by purging with carbon dioxide at a flow rate of 20mL / min (activation temperature was 700℃, activation time was 1h). Nitrogen was then purged again to cool to room temperature, and the material was washed with deionized water and dried to obtain 94.2mg of pore-forming carbon black material (specific surface area of ​​500-800m²). 2 / g) for later use;

[0024] (2) Take 94.2 mg of the porous carbon black material from step (1), add 40 wt% nitric acid at a mass ratio of 1:4, stir and heat to 100℃ for reflux treatment, react for 2 h, wash until neutral, filter and dry to obtain 88.8 mg of porous carbon black material (specific surface area of ​​800-1000 m²). 2 / g) for later use;

[0025] (3) Take 88.8 mg of porous carbon black material from step (2), add it to a mixed amino acid solution (a solution made by mixing lysine, phenylalanine and purified water in a mass-volume ratio of 2 mg:1 mg:5 mL) at a mass-volume ratio of 1:1.2 (mg / ml), adjust the pH to 7, heat to 50°C, and ultrasonically disperse (ultrasonic dispersion power of 400 W, ultrasonic dispersion time of 15 min), rinse, filter and dry to obtain 112.3 mg of carbon black material loaded with mixed amino acid adsorption layer for later use;

[0026] (4) Take 112.3 mg of carbon black material loaded with mixed amino acid adsorption layer in step (3), add deionized water at a mass-volume ratio of 1:1.2 (mg / ml), add 0.08 mol / L silver nitrate solution (mass ratio of silver nitrate in carbon black material to silver nitrate solution is 3.2:1) to the carbon black material solution after stirring, and then add 0.08 mol / L sodium borohydride solution and continue stirring. Control the reaction pH to 8 and the reaction temperature to 25℃. After the reaction is completed, filter, wash and dry to obtain 134.6 mg of highly conductive carbon black product. Example 2

[0027] A production process for improving the conductivity of carbon black includes the following steps:

[0028] (1) Take 100 mg of carbon black with a particle size of 30-40 nm (specific surface area of ​​80-130 m²). 2 The carbon black material was first preheated by purging with nitrogen (heated to 350℃ at a heating rate of 6.5℃ / min), and then activated by purging with carbon dioxide at a flow rate of 30mL / min (activation temperature 750℃, activation time 1.2h). Nitrogen was then purged again to cool to room temperature, followed by washing with deionized water and drying to obtain 93.1mg of pore-forming carbon black material (specific surface area 600-900m²). 2 / g) for later use;

[0029] (2) Take 93.1 mg of the porous carbon black material from step (1), add 42 wt% nitric acid at a mass ratio of 1:5, stir and heat to 105℃ for reflux treatment, react for 2.5 h, wash until neutral, filter and dry to obtain 85.8 mg of porous carbon black material (specific surface area of ​​900-1300 m²). 2 / g) for later use;

[0030] (3) Take 85.8 mg of porous carbon black material from step (2), add it to a mixed amino acid solution (a solution made by mixing lysine, phenylalanine and purified water in a mass-volume ratio of 2.5 mg:1.5 mg:8 mL) at a mass ratio of 1:1.5 (mg / ml), adjust the pH to 7.2, heat to 55℃, and perform ultrasonic dispersion treatment (ultrasonic dispersion power of 420w, ultrasonic dispersion time of 20min), rinse, filter and dry to obtain 112.5 mg of carbon black material loaded with mixed amino acid adsorption layer for later use;

[0031] (4) Take 112.5 mg of carbon black material loaded with mixed amino acid adsorption layer in step (3), add deionized water at a mass-volume ratio of 1:1.3 (mg / ml), stir and mix, then add 0.1 mol / L silver nitrate solution (the mass ratio of silver nitrate in carbon black material to silver nitrate solution is 3:1), stir and mix, then add 0.1 mol / L sodium borohydride solution dropwise, control the reaction pH to 8.5, and the reaction temperature to 30℃. After the reaction is completed, filter, wash and dry to obtain 136.2 mg of highly conductive carbon black product. Example 3

[0032] A production process for improving the conductivity of carbon black includes the following steps:

[0033] (1) Take 100 mg of carbon black with a particle size of 30-40 nm (specific surface area of ​​80-130 m²). 2 The carbon black material was first preheated by purging with nitrogen (heated to 400℃ at a heating rate of 7.5℃ / min), and then activated by purging with carbon dioxide at a flow rate of 40mL / min (activation temperature was 800℃, activation time was 1.5h). Nitrogen was then purged again to cool to room temperature, and the material was washed with deionized water and dried to obtain 92.5mg of pore-formed carbon black material (specific surface area of ​​800-1100m²). 2 / g) for later use;

[0034] (2) Take 92.5 mg of the porous carbon black material from step (1), add 45 wt% nitric acid at a mass ratio of 1:6, stir and heat to 110℃ for reflux treatment, react for 3 h, wash until neutral, filter and dry to obtain 84.6 mg of porous carbon black material (1100-1400m).2 / g) for later use;

[0035] (3) Take 84.6 mg of porous carbon black material from step (2), add it to a mixed amino acid solution (a solution of lysine, phenylalanine and purified water mixed in a mass-volume ratio of 3.5 mg: 2.8 mg: 12 mL) at a mass-volume ratio of 1:1.7 (mg / ml), adjust the pH to 7.5, heat to 60℃, and ultrasonically disperse (ultrasonic dispersion power of 450w, ultrasonic dispersion time of 25min), rinse, filter and dry to obtain 119.1 mg of carbon black material loaded with mixed amino acid adsorption layer for later use;

[0036] (4) Take 119.1 mg of carbon black material loaded with mixed amino acid adsorption layer in step (3), add deionized water at a mass-volume ratio of 1:1.4 (mg / ml) and stir. Then add 0.13 mol / L silver nitrate solution (the mass ratio of silver nitrate in carbon black material to silver nitrate solution is 2:1), stir and mix. Then add 0.13 mol / L sodium borohydride solution dropwise and continue stirring and mixing. Control the reaction pH to 9 and the reaction temperature to 35℃. After the reaction is completed, filter, wash and dry to obtain 156.8 mg of highly conductive carbon black product. Example 4

[0037] A production process for improving the conductivity of carbon black includes the following steps:

[0038] (1) Take 100 mg of carbon black with a particle size of 30-40 nm (specific surface area of ​​80-130 m²). 2 The carbon black material was first preheated by purging with nitrogen (heated to 420℃ at a heating rate of 8.5℃ / min), and then activated by purging with carbon dioxide at a flow rate of 50mL / min (activation temperature was 850℃, activation time was 1.8h). Nitrogen was then purged again to cool to room temperature, followed by washing with deionized water and drying to obtain 91.7mg of pore-forming carbon black material (specific surface area of ​​900-1200m²). 2 / g) for later use;

[0039] (2) Take 91.7 mg of the porous carbon black material from step (1), add 48 wt% nitric acid at a mass ratio of 1:7, stir and heat to 115℃ for reflux treatment, react for 3.5 h, wash until neutral, filter and dry to obtain 83.1 mg of porous carbon black material (specific surface area of ​​1200-1500 m²). 2 / g) for later use;

[0040] (3) Take 83.1 mg of porous carbon black material from step (2), add it to a mixed amino acid solution (a solution of lysine, phenylalanine and purified water mixed in a mass-volume ratio of 3 mg: 2.5 mg: 10 mL) at a mass-volume ratio of 1:1.3 (mg / ml), adjust the pH to 7.8, heat to 65℃, and perform ultrasonic dispersion treatment (ultrasonic dispersion power of 480w, ultrasonic dispersion time of 30min), rinse, filter and dry to obtain 108.8 mg of carbon black material loaded with mixed amino acid adsorption layer for later use;

[0041] (4) Take 108.8 mg of carbon black material loaded with mixed amino acid adsorption layer in step (3), add deionized water at a mass-volume ratio of 1:1.5 (mg / ml), stir and mix, then add 0.16 mol / L silver nitrate solution (the mass ratio of silver nitrate in carbon black material to silver nitrate solution is 2.5:1), stir and mix, then add 0.16 mol / L sodium borohydride solution dropwise and continue stirring and mixing, control the pH to 9.5, control the reaction temperature to 40℃, filter, wash and dry after the reaction, and you can get 136.3 mg of highly conductive carbon black product. Example 5

[0042] A production process for improving the conductivity of carbon black includes the following steps:

[0043] (1) Take 100 mg of carbon black with a particle size of 30-40 nm (specific surface area of ​​80-130 m²). 2 The carbon black material was first preheated by purging with nitrogen (heated to 450℃ at a heating rate of 10℃ / min), and then activated by purging with carbon dioxide at a flow rate of 60mL / min (activation temperature was 900℃, activation time was 2h). Nitrogen was then purged again to cool to room temperature, and the material was washed with deionized water and dried to obtain 90.2mg of pore-forming carbon black material (specific surface area of ​​900-1300m²). 2 / g) for later use;

[0044] (2) Take 90.2 mg of the porous carbon black material from step (1), add 50 wt% nitric acid at a mass ratio of 1:8, stir and heat to 120℃ for reflux treatment, react for 4 h, wash until neutral, filter and dry to obtain 81.1 mg of porous carbon black material (specific surface area of ​​1300-1600 m²). 2 / g) for later use;

[0045] (3) Take 81.1 mg of porous carbon black material from step (2), add it to a mixed amino acid solution (a solution of lysine, phenylalanine and purified water mixed in a mass-volume ratio of 4 mg:3 mg:15 mL) at a mass-volume ratio of 1:1.8 (mg / ml), adjust the pH to 8, heat to 70℃, and perform ultrasonic dispersion treatment (the ultrasonic dispersion power is 500w, and the ultrasonic dispersion time is 35min). After rinsing, filtering and drying, 113.3 mg of carbon black material loaded with mixed amino acid adsorption layer is obtained for later use.

[0046] (4) Take 113.3 mg of carbon black material loaded with the mixed amino acid adsorption layer in step (3), add deionized water at a mass-volume ratio of 1:1.5 (mg / ml), stir and mix, then add 0.18 mol / L silver nitrate solution (the mass ratio of silver nitrate in carbon black material to silver nitrate solution is 2.3:1), stir and mix, then add 0.18 mol / L sodium borohydride solution dropwise and continue stirring and mixing, control the pH to 10, and the reaction temperature to 45℃. After the reaction is completed, filter, wash and dry to obtain 144.3 mg of highly conductive carbon black product.

[0047] To better demonstrate that the process of the present invention can yield a highly conductive carbon black product, the following comparative examples are provided with reference to Example 3. The DBP oil absorption values ​​of the conductive carbon blacks in Examples 1-5 and the comparative examples were determined using the experimental methods specified in the national standard GB / T3780.2-2003 "Carbon Black Part 2: Determination of Dibutyl Phthalate Absorbance". The resistivity of the conductive carbon blacks in Examples 1-5 and the comparative examples was determined using the methods specified in the national standard GB / T3781.9-2006 "Acetylene Black Part 9: Determination of Resistivity". See Table 1 for details.

[0048] Comparative Example 1

[0049] Unlike Example 3, in step (3), the pH was adjusted to 6, and the rest of the operation was the same; in step (3), 92.9 mg of carbon black material loaded with mixed amino acid adsorption layer was prepared for use; in step (4), 104.6 mg of highly conductive carbon black product was prepared.

[0050] Comparative Example 2

[0051] Unlike Example 3, in step (3), the pH was adjusted to 9, and the rest of the operation was the same; in step (3), 95.8 mg of carbon black material loaded with mixed amino acid adsorption layer was prepared for use; in step (4), 110.7 mg of highly conductive carbon black product was prepared.

[0052] Comparative Example 3

[0053] Unlike Example 3, in step (3), the temperature was raised to 45°C, and the rest of the operation was the same; in step (3), 98.7 mg of carbon black material loaded with mixed amino acid adsorption layer was prepared for use; in step (4), 112.3 mg of highly conductive carbon black product was prepared.

[0054] Comparative Example 4

[0055] Unlike Example 3, in step (3), the temperature was raised to 75°C, while the rest of the operation was the same. In step (3), 107.9 mg of carbon black material with a mixed amino acid adsorption layer was obtained for later use; in step (4), 123.4 mg of highly conductive carbon black product was obtained.

[0056] Comparative Example 5

[0057] Unlike Example 3, the reaction temperature in step (4) was controlled at 20°C, while the rest of the operation was the same. In step (4), 140.5 mg of highly conductive carbon black product was obtained.

[0058] Comparative Example 6

[0059] Unlike Example 3, the reaction temperature in step (4) was controlled at 50°C, while the rest of the operation was the same. In step (4), 134.6 mg of highly conductive carbon black product was obtained.

[0060] Comparative Example 7

[0061] Unlike Example 3, in step (4), the mass ratio of carbon black material to silver nitrate in the silver nitrate solution is 1.5:1, and the rest of the operation is the same. In step (4), 164.2 mg of highly conductive carbon black product was obtained.

[0062] Comparative Example 8

[0063] Unlike Example 3, in step (4), the mass ratio of carbon black material to silver nitrate in the silver nitrate solution is 4:1, and the rest of the operation is the same. In step (4), 138 mg of highly conductive carbon black product is obtained.

[0064] Comparative Example 9

[0065] Unlike Example 3, step (3) is omitted, while the rest of the operations are the same. In step (4), 94.7 mg of highly conductive carbon black product is obtained.

[0066]

[0067] The data in Table 1 shows that the carbon black product prepared using the process method of Example 3 of the present invention has better overall conductivity than other examples and comparative examples.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for improving the electrical conductivity of carbon black, characterized in that, The production process comprises the following steps: (1) Take carbon black, first pass nitrogen through preheating treatment, and then pass carbon dioxide for activation treatment, after the activation treatment is completed, nitrogen is passed again to reduce to room temperature, washing, drying, to obtain the pore-making carbon black material for standby; (2) Take the pore-making carbon black material in step (1), add nitric acid after heating and stirring, after the reaction is completed, wash to neutral, filter, dry to obtain the porous carbon black material for standby; (3) Take the porous carbon black material in step (2), add mixed amino acid solution, adjust pH after heating, ultrasonic dispersion treatment, filter, dry to obtain the carbon black material loaded with mixed amino acid adsorption layer for standby; The porous carbon black material and the mixed amino acid solution are mixed in a mass-volume ratio of 1 mg:1.2-1.8 ml; The mixed amino acid solution is a solution prepared by mixing lysine, phenylalanine and purified water in a mass-volume ratio of 2-4 mg:1-3 mg:5-15 mL; Adjust the pH to 7-8, heat to 50-70 DEG C, the ultrasonic dispersion power is 400-500 w, the ultrasonic dispersion time is 15-35 min; (4) Take the carbon black material loaded with mixed amino acid adsorption layer in step (3), add deionized water and stir, add silver nitrate solution to the obtained carbon black slurry, stir uniformly, then add sodium borohydride solution dropwise and continue to stir, control the pH and reaction temperature, after the reaction is completed, filter, wash, dry, to obtain the high-conductivity carbon black product; The mass ratio of the carbon black material loaded with mixed amino acid adsorption layer to silver nitrate in the silver nitrate solution is 2-3.2:1, the concentration of the silver nitrate solution and the concentration of the sodium borohydride are both 0.08-0.18 mol / L; Control the pH at 8-10, control the reaction temperature at 25-45 DEG C.

2. The process for improving the electrical conductivity of carbon black as claimed in claim 1 wherein, In step (1), the carbon black material is heated to 300-450 DEG C at a heating rate of 5-10 DEG C / min during preheating treatment.

3. The production process for improving the conductivity of carbon black according to claim 1, characterized in that, In step (1), the flow rate of carbon dioxide during activation treatment is 20-60 mL / min, the activation treatment temperature is controlled at 700-900 DEG C, and the activation treatment time is controlled at 1-2 h.

4. The production process for improving the conductivity of carbon black according to claim 1, characterized in that, In step (2), the pore-making carbon black material and the nitric acid are mixed in a mass ratio of 1:4-8, and the concentration of the nitric acid is 40-50 wt%.

5. The production process for improving the conductivity of carbon black according to claim 1, characterized in that, In step (2), heat to 100-120 DEG C, control the reaction time for 2-4 h.

6. The production process for improving the conductivity of carbon black according to claim 1, characterized in that, In step (4), the carbon black material loaded with mixed amino acid adsorption layer and the deionized water are mixed in a mass-volume ratio of 1 mg:1.2-1.5 ml.

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