High-dispersity conductive carbon black, preparation method thereof and high-voltage cable

Abstract

The invention relates to high-dispersity conductive carbon black, a preparation method thereof and a high-voltage cable. The preparation method of the high-dispersity conductive carbon black comprises the following steps: performing wet granulation on furnace carbon black powder to form a carbon black mixture; and carrying out supercritical treatment on the carbon black mixture to obtain the high-dispersity conductive carbon black. According to the preparation method, the carbon black mixture subjected to wet granulation is subjected to supercritical treatment, and the permeability of supercritical carbon dioxide to carbon black particles is further enhanced through the high-pressure condition and the carbon black mixture in a wet state, so that the supercritical carbon dioxide can more easily permeate into internal micropores of the carbon black particles; the high-dispersity conductive carbon black with excellent dispersity and high structural degree can be obtained.

Description

Technical Field

[0001] The present application relates to the field of cable materials, and in particular to a highly dispersed conductive carbon black and a preparation method thereof, and a high-voltage cable. Background Art

[0002] The structure of power cables involves metal conductor cores, insulation layers, semi-conductive shielding layers and sheaths. The main function of the semi-conductive shielding layer is to fill the air gap, form a smooth and uniform connection interface, and then even out the electric field strength on the surface of the core to reduce tip discharge. Conductive carbon black is a key raw material for forming a semi-conductive shielding layer. Improving the structural degree of conductive carbon black helps the semi-conductive shielding layer form a more developed conductive connection network and obtain better electrical properties.

[0003] However, highly structured conductive carbon black usually has a higher surface energy and stronger interaction between particles, which makes it easy for carbon black particles to agglomerate in the matrix and difficult to achieve uniform dispersion. This agglomeration phenomenon not only reduces the effective utilization of carbon black and the contact area between carbon black particles and the matrix, but also may lead to uneven structure of the semi-conductive shielding layer, which in turn causes uneven electric field distribution and significantly deteriorates the electrical performance of the semi-conductive shielding layer. Summary of the invention

[0004] Based on this, it is necessary to provide a highly dispersed conductive carbon black having excellent dispersibility and high structure, a preparation method thereof, and a high-voltage cable.

[0005] In a first aspect of the present application, a method for preparing highly dispersed conductive carbon black is provided.

[0006] A method for preparing highly dispersible conductive carbon black comprises the following steps:

[0007] wet granulating the furnace carbon black powder to form a carbon black mixture;

[0008] Performing supercritical treatment on the carbon black mixture to obtain highly dispersed conductive carbon black;

[0009] The supercritical treatment includes: mixing the carbon black mixture with supercritical carbon dioxide at a pressure of 80 MPa to 120 MPa.

[0010] In some embodiments, the wet granulation step comprises:

[0011] mixing the furnace carbon black powder and water to form an intermediate mixture;

[0012] The intermediate mixture is mixed with a binder to form the carbon black mixture.

[0013] In some of these embodiments, the mass ratio of the furnace black powder to the water is 1:(10 to 20).

[0014] In some of these embodiments, the binder includes one or more of polyacrylic acid, polyvinyl ketone, and lignin; the mass ratio of the intermediate mixture to the binder is 1:(0.05 to 0.1).

[0015] In some of these embodiments, it further includes a step of post-treating the carbon black mixture after the supercritical treatment, and the post-treatment includes drying, desorption, and refining.

[0016] In some of these embodiments, the preparation step of the furnace black powder includes:

[0017] Mixing the feedstock oil, air, and natural gas in a reaction furnace and carrying out a cracking reaction to form the furnace black powder.

[0018] In some of these embodiments, one or more of the following conditions are satisfied:

[0019] (1) The volume ratio of the air to the natural gas is (17 to 20):1;

[0020] (2) The time of the cracking reaction is 30 ms to 60 ms;

[0021] (3) The temperature of the cracking reaction is 1600 °C to 1800 °C;

[0022] (4) The flow rate of the feedstock oil into the reaction furnace is 3000 kg / h to 3500 kg / h.

[0023] In some of these embodiments, when the ash content of the feedstock oil ≤ 0.03%, the supercritical treatment satisfies the following conditions:

[0024] The treatment time of the supercritical treatment is 1 h to 6 h;

[0025] The temperature of the supercritical treatment is 30 °C to 50 °C;

[0026] The mixing rate of the supercritical treatment is 10 rpm to 60 rpm.

[0027] In some of these embodiments, when the ash content of the feedstock oil > 0.03%, the supercritical treatment satisfies the following conditions:

[0028] The treatment time of the supercritical treatment is 6 h to 12 h;

[0029] The temperature of the supercritical treatment is 50 °C to 80 °C;

[0030] The mixing rate of the supercritical treatment is 20 rpm to 80 rpm.

[0031] In the second aspect of the present application, a highly dispersible conductive carbon black is provided.

[0032] A highly dispersible conductive carbon black is prepared by using the preparation method of the highly dispersible conductive carbon black described above.

[0033] In the third aspect of the present application, a high-voltage cable is provided.

[0034] A high-voltage cable includes a conductor, an insulating layer, and a semiconductive shielding layer; the conductor is located inside the insulating layer, and the semiconductive shielding layer is located on at least one surface of the insulating layer; the conductive filler of the semiconductive shielding layer includes the above-mentioned highly dispersible conductive carbon black or the highly dispersible conductive carbon black prepared by the above-mentioned preparation method.

[0035] In the above preparation method of the highly dispersible conductive carbon black, by performing supercritical treatment on the carbon black mixture after wet granulation under high pressure, supercritical carbon dioxide can more easily enter the internal micropores of the carbon black particles and improve the polarity of the carbon black particles, thereby effectively reducing the agglomeration between the carbon black particles. The above preparation method of the highly dispersible conductive carbon black can obtain a highly dispersible conductive carbon black with both excellent dispersibility and high structure degree, and has a simple process and high efficiency, and has the application prospect of industrial batch production. Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0037] Figure 1 It is the preparation flow chart of the highly dispersible conductive carbon black of Embodiment 1 of the present application.

[0038] Reference Signs:

[0039] 101, raw material oil inlet; 102, air inlet; 103, natural gas inlet; 104, auxiliary agent inlet; 105, cooling water inlet; 110, reaction furnace; 120, collection chamber; 130, granulation chamber; 140, supercritical treatment chamber. Detailed Embodiments

[0040] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application. Many specific details are set forth in the following description to facilitate a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0041] In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined. In the present application, the meaning of "at least one kind" is more than one kind, such as one kind, two kinds, and more than two kinds. The meaning of "a variety of" or "several kinds" is at least two, such as two, three, etc.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0043] When a numerical range is disclosed herein, the above range is considered continuous and includes the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Further, when the range refers to integers, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0044] If there is no special indication, all steps of the present application can be carried out in sequence or randomly. For example, the method includes steps (a) and (b), which means that the method can include steps (a) and (b) carried out in sequence, or can also include steps (b) and (a) carried out in sequence. For example, it is mentioned that the method may further include step (c), which means that step (c) can be added to the method in any order. For example, the method can include steps (a), (b), and (c) in sequence, or can also include steps (a), (c), and (b), or can also include steps (c), (a), and (b), etc.

[0045] In the present application, "above" or "below" both include the number itself. For example, below 1 includes 1.

[0046] The temperature parameters in this application, unless otherwise specified, allow for both constant temperature treatment and fluctuations within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0047] The structure of a power cable involves parts such as a metal conductor core, an insulating layer, a semi-conductive shielding layer, and a sheath. In the structure of a power cable, the main function of the semi-conductive shielding layer is to fill air gaps, form a smooth and uniform connection interface, thereby equalizing the electric field strength on the surface of the core and reducing the phenomenon of tip discharge. Conductive carbon black is the key raw material for forming the semi-conductive shielding layer. Improving the structure degree of conductive carbon black helps the semi-conductive shielding layer to form a more developed conductive connection network and obtain more excellent electrical properties.

[0048] However, the surface energy of high-structure conductive carbon black is usually high, and there is a stronger interaction force between particles, making the carbon black particles prone to agglomeration in the matrix and difficult to achieve uniform dispersion. This agglomeration phenomenon not only reduces the effective utilization rate of carbon black, decreases the contact area between carbon black particles and the matrix, but also may lead to non-uniformity in the structure of the semi-conductive shielding layer, thereby causing uneven electric field distribution and significantly deteriorating the electrical properties of the semi-conductive shielding layer.

[0049] To overcome the agglomeration problem of high-structure conductive carbon black, researchers have tried various dispersion techniques and methods, such as surface modification method, polymerization coating method, high-shear dispersion method, additive-assisted dispersion method, temperature-controlled dispersion method, etc. However, these dispersion methods often have problems such as complex operation, high energy consumption, and unstable dispersion effect in practical applications, and it is difficult to fully meet the preparation requirements of high-performance shielding materials.

[0050] Based on this, in the first aspect of this application, a highly dispersible conductive carbon black and its preparation method are provided. Through this preparation method, conductive carbon black with both excellent dispersibility and high structure degree can be obtained.

[0051] The preparation method of the highly dispersible conductive carbon black includes the following steps:

[0052] Perform wet granulation on the furnace black powder to form a carbon black mixture;

[0053] Perform supercritical treatment on the carbon black mixture to obtain highly dispersible conductive carbon black;

[0054] Among them, the supercritical treatment includes: mixing the carbon black mixture with supercritical carbon dioxide under a pressure of 80 Mpa to 120 Mpa.

[0055] The preparation method of the above high-dispersion conductive carbon black performs supercritical treatment on the carbon black mixture after wet granulation. Through high-pressure conditions and the carbon black mixture in a wet state, the permeability of supercritical carbon dioxide to carbon black particles is further enhanced, enabling supercritical carbon dioxide to more easily penetrate into the internal micropores of carbon black particles. Furthermore, the surface of carbon black particles can be modified by supercritical carbon dioxide, reducing the agglomeration phenomenon between carbon black particles.

[0056] In some of these embodiments, the mixing pressure during supercritical treatment can be, but is not limited to, 80 Mpa, 85 Mpa, 90 Mpa, 95 Mpa, 100 Mpa, 110 Mpa, 120 Mpa, or other values within the range of 80 Mpa to 120 Mpa. When the pressure is relatively low, the penetration ability of supercritical carbon dioxide into the interior of carbon black is limited, and it is difficult to play an effective modification role; however, when the pressure is too high, not only is the improvement of the penetration ability limited, but it may even cause the destruction of the branched-chain structure of carbon black. Maintaining the above pressure range helps to obtain conductive carbon black with both excellent dispersibility and high structure.

[0057] It can be understood that the carbon black mixture in the above method is a carbon black mixture with a wet surface that has not been dried after wet granulation. Using the carbon black mixture as the modification basis for supercritical treatment can not only improve the modification effect of supercritical treatment but also protect the intrinsic structure of carbon black particles from the influence of high pressure to a certain extent.

[0058] In some of these embodiments, the temperature of supercritical treatment can be, but is not limited to, 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, or other values within the range of 30 °C to 80 °C. Temperature affects the density of supercritical carbon dioxide and the ease of elution of functional groups on the surface of carbon black particles. Keeping the temperature within the above range helps to improve the ability of supercritical carbon dioxide to remove impurities on the surface of carbon black particles.

[0059] In some of these embodiments, the mixing rate of supercritical treatment is 10 rpm to 40 rpm. It can be understood that the mixing rate is the stirring rate.

[0060] In some of these embodiments, the steps of wet granulation include:

[0061] Mix furnace black powder and water to form an intermediate mixture;

[0062] Mix the intermediate mixture with a binder to form a carbon black mixture.

[0063] In some of these embodiments, the mass ratio of furnace black powder to water is 1:(10 - 20). Optionally, the mass ratio of furnace black powder to water can be, but is not limited to, 1:10, 1:12, 1:14, 1:16, 1:18, 1:20, or other values within the range of 1:(10 - 20).

[0064] In some of these embodiments, the binder includes one or more of polyacrylic acid, polyvinyl ketone, and lignin.

[0065] In some of these embodiments, the mass ratio of the intermediate mixture to the binder is 1:(0.05 - 0.1).

[0066] In some of these embodiments, it further includes the step of post - treating the carbon black mixture after supercritical treatment, and the post - treatment includes drying, desorption, and refining.

[0067] In some of these embodiments, the carbon black mixture is subjected to supercritical treatment to obtain a modified carbon black mixture, and the modified carbon black mixture is post - treated to obtain highly - dispersed conductive carbon black. Performing supercritical treatment first can not only achieve preliminary impurity removal, but also reduce the electrostatic adsorption between carbon black mixtures, thereby improving the treatment effect of the post - treatment.

[0068] In some of these embodiments, the drying temperature is 100°C - 200°C.

[0069] In some of these embodiments, under an inert gas atmosphere, the dried modified carbon black mixture is subjected to nitrogen desorption at a temperature of 200°C - 400°C. Through desorption, impurities on the carbon black surface are further removed.

[0070] In some of these embodiments, a carbon slag remover, a sieve, an air - sieve, and a multi - stage magnetic separator are used to refine the desorbed modified carbon black mixture to obtain highly - dispersed conductive carbon black.

[0071] In some of these embodiments, the preparation steps of the furnace black powder include:

[0072] Mixing the feedstock oil, air, and natural gas in a reaction furnace and carrying out a cracking reaction to form furnace black powder.

[0073] In some of these embodiments, the volume ratio of air to the natural gas is (17 - 20):1. Optionally, the volume ratio of air to the natural gas can be, but is not limited to, 17:1, 18:1, 19:1, 20:1, or other values within the range of (17 - 20):1.

[0074] In some of these embodiments, the flue gas flow rate in the reaction furnace is 90 m / s - 110 m / s.

[0075] In some of these embodiments, the flow rate of the feedstock oil into the reaction furnace is 3000 kg / h to 3500 kg / h.

[0076] In some of these embodiments, the temperature of the cracking reaction is 1600 °C to 1800 °C, and the time of the cracking reaction is 30 ms to 60 ms. Maintaining the feedstock oil to undergo the cracking reaction at the above temperature and time helps to obtain furnace black with small particle size, long chain-branched structure and not easily broken at high temperature.

[0077] In some of these embodiments, the reaction time is controlled by controlling the reaction temperature. Exemplarily, cooling water is sprayed into the outlet of the reaction furnace through a spraying device to reduce the temperature and terminate the reaction.

[0078] In some of these embodiments, it further includes the step of mixing the feedstock oil, air, natural gas and additives.

[0079] In some of these embodiments, the additives include one or more of metal catalysts, surfactants, polymerization inhibitors and nucleating agents, and the flow rate of the additives is 0.1 L / h to 1 L / h. Optionally, the metal catalyst includes one or more of potassium carbonate and iron nitrate. The surfactant includes Tween-80. The polymerization inhibitor includes sodium sulfide. The nucleating agent includes one or more of silicon oxide and titanate.

[0080] In some of these embodiments, it further includes the step of pre-treating the feedstock oil. The feedstock oil is heated to 60 °C to 90 °C, and after mixing, sedimentation and filtration, the residues and impurities are removed, and then it is preheated to 200 °C to 300 °C.

[0081] In some of these embodiments, the feedstock oil includes one or more of coal tar, anthracene oil and ethylene tar.

[0082] In some of these embodiments, the ash content of the coal tar is ≤0.1%, the moisture content is ≤4%, the toluene-insoluble matter is ≤5.5%, and the density at 20 °C is 1.16 to 1.2 g / cm 3 , and the viscosity is ≤6.0.

[0083] In some of these embodiments, the ash content of the anthracene oil is ≤0.02%, the moisture content is ≤0.5%, the toluene-insoluble matter is ≤0.2%, and the density at 20 °C is 1.12 to 1.14 g / cm 3 , and the viscosity is ≤1.5.

[0084] In some of these embodiments, the ash content of the ethylene tar is ≤0.03%, the moisture content is ≤0.5%, the toluene-insoluble matter is ≤0.3%, and the density is 1.06 to 1.10 g / cm 3 , and the viscosity is ≤6.0.

[0085] In some of these embodiments, when the ash content of the feedstock oil is ≤ 0.03%, the temperature of the supercritical treatment is 30°C to 50°C, the mixing rate is 10 rpm to 60 rpm, and the treatment time is 1 h to 6 h. Maintaining the supercritical treatment under the above conditions can better achieve the modification effect on the carbon black prepared from the feedstock oil with a lower impurity content.

[0086] In some of these embodiments, when the ash content of the feedstock oil is > 0.03%, the temperature of the supercritical treatment is 50°C to 80°C, the mixing rate is 20 rpm to 80 rpm, and the treatment time is 6 h to 12 h. Increasing the mixing degree and treatment time of the supercritical treatment can better achieve the dispersibility modification effect on the carbon black prepared from the feedstock oil with a higher impurity content.

[0087] In the second aspect of the present application, there is provided a highly dispersible conductive carbon black prepared by using the preparation method of the above-mentioned highly dispersible conductive carbon black.

[0088] In the third aspect of the present application, there is provided a high-voltage cable. The high-voltage cable includes a conductor, an insulating layer, and a semiconductive shielding layer. Among them, the conductor is located inside the insulating layer, and the semiconductive shielding layer is located on at least one surface of the insulating layer. The conductive filler of the semiconductive shielding layer contains the above-mentioned highly dispersible conductive carbon black or the highly dispersible conductive carbon black prepared by the above-mentioned preparation method.

[0089] The following further describes the present application in detail with specific examples.

[0090] In the following specific examples and comparative examples, the raw materials used are all commercially available products unless otherwise specified; the instruments used are all commercially available products unless otherwise specified; the processes used are all conventional selections by those skilled in the art unless otherwise specified.

[0091] Example 1

[0092] This example provides a highly dispersible conductive carbon black.

[0093] Please refer to Figure 1 , Figure 1 which is the preparation flow chart of the highly dispersible conductive carbon black in Example 1 of the present application. The preparation process of the highly dispersible conductive carbon black is as follows:

[0094] The feedstock oil is heated to 80°C, preheated to 220°C after sedimentation and filtration, and reserved for use. The feedstock oil is passed into the reaction furnace at a flow rate of 3200 kg / h through the feedstock oil inlet 101, air is passed into the reaction furnace 110 at 100 m / s through the air inlet 102, natural gas is passed into the reaction furnace 110 at 100 m / s through the natural gas inlet 103, and the additive is passed into the reaction furnace 110 at 0.5 L / h through the additive inlet 104. The feedstock oil, air, natural gas, and additive are reacted at 1600°C for about 40 ms, cooled at the cooling water inlet 105, and then passed into the collection chamber 120. After filtering and removing impurities in the collection chamber 120, furnace black powder is obtained. Among them, the feedstock oil is anthracene oil, the ash content of anthracene oil is 0.02%, the water content is 0.4%, the toluene-insoluble matter is 0.2%, and the density at 20°C is 1.131 g / cm 3 , and the viscosity is 1.3. The additive is potassium carbonate, Tween-80, sodium sulfide, and silicon oxide.

[0095] The furnace black powder is passed into the granulation chamber 130, the furnace black powder and water are mixed at a mass ratio of 1:15, and an intermediate mixture is obtained after stirring. Then, a granulating agent is added to form a granular carbon black mixture.

[0096] The carbon black mixture is passed into the supercritical treatment chamber 140, continuously mixed with supercritical carbon dioxide at 80 Mpa and 40°C at 40 rpm for 1 h to obtain highly dispersible conductive carbon black.

[0097] The carbon black mixture after supercritical treatment is post-treated, and the post-treatment is drying, desorption, and refining. Among them, the drying step is: drying at 150°C for 1 h. The desorption step is: nitrogen desorption at 350°C under a protective gas atmosphere. The refining step is: refining using a carbon slag remover, a screening machine, a pneumatic sieve machine, and a multi-stage magnetic separator.

[0098] Example 2

[0099] This example provides a highly dispersible conductive carbon black.

[0100] The preparation method of the highly dispersible conductive carbon black in this example is basically the same as that in Example 1, except that: the pressure of supercritical treatment is 100 Mpa.

[0101] Example 3

[0102] This example provides a highly dispersible conductive carbon black.

[0103] The preparation method of the highly dispersible conductive carbon black in this example is basically the same as that in Example 1, except that: the pressure of supercritical treatment is 120 Mpa.

[0104] Example 4

[0105] This embodiment provides a highly dispersible conductive carbon black.

[0106] The preparation method of the highly dispersible conductive carbon black in this embodiment is basically the same as that in Embodiment 1, except that the supercritical treatment time is 3 h.

[0107] Embodiment 5

[0108] This embodiment provides a highly dispersible conductive carbon black.

[0109] The preparation method of the highly dispersible conductive carbon black in this embodiment is basically the same as that in Embodiment 1, except that the raw material oil is coal tar, the ash content of the coal tar is 0.1%, the water content is 2%, and the toluene-insoluble matter is 3.5%. During supercritical treatment, the stirring rate is 10 rmp and the treatment time is 6 h.

[0110] Comparative Example 1

[0111] This comparative example provides a conductive carbon black.

[0112] The preparation method of the conductive carbon black in this comparative example is basically the same as that of the highly dispersible conductive carbon black in Embodiment 1, except that supercritical treatment is not performed.

[0113] Comparative Example 2

[0114] This comparative example provides a conductive carbon black.

[0115] The preparation method of the conductive carbon black in this comparative example is basically the same as that of the highly dispersible conductive carbon black in Embodiment 5, except that supercritical treatment is not performed.

[0116] Comparative Example 3

[0117] This comparative example provides a highly dispersible conductive carbon black.

[0118] The preparation method of the highly dispersible conductive carbon black in this comparative example is basically the same as that in Embodiment 1, except that the supercritical treatment pressure is 50 Mpa.

[0119] Comparative Example 4

[0120] This comparative example provides a highly dispersible conductive carbon black.

[0121] The preparation method of the highly dispersible conductive carbon black in this comparative example is basically the same as that in Embodiment 1, except that the supercritical treatment pressure is 140 Mpa.

[0122] Comparative Example 5

[0123] This comparative example provides a highly dispersible conductive carbon black.

[0124] The preparation method of the highly dispersed conductive carbon black in this comparative example is basically the same as that in Example 1, except that: the carbon black mixture is post-treated first to obtain conductive carbon black, and the conductive carbon black is supercritically treated, and the highly dispersed conductive carbon black is obtained after drying.

[0125] Test Example

[0126] The performance of the conductive carbon blacks in Examples 1-6 and Comparative Examples 1-5 was tested, and the test results are shown in Table 1. Among them, the BET test was carried out by the method of GBT19587-2017.

[0127] Table 1 Test Results of Conductive Carbon Black Performance

[0128]

[0129] As can be seen from Table 1, the preparation method of the highly dispersed conductive carbon black of the present application can increase the Zeta potential of the carbon black, making the carbon black particles have a strong repulsive ability, which helps to reduce the agglomeration phenomenon among the carbon blacks. From the test results of the water contact angle, it can be seen that the preparation method of the highly dispersed conductive carbon black of the present application can improve the hydrophilicity of the carbon black surface, which helps to improve the dispersibility and stability of the carbon black, and also indicates that the supercritical treatment can increase the number of polar functional groups on the carbon black surface. From the test results of the DBP value, it can be seen that the preparation method of the highly dispersed conductive carbon black of the present application can avoid damaging the intrinsic structure of the carbon black, and can obtain highly dispersed conductive carbon black with both excellent dispersibility and high structure. By comparing Example 1 and Comparative Example 5, it can be seen that supercritically treating the undried carbon black mixture is more helpful for improving the polarity of the carbon black surface and enhancing the dispersibility. In addition, the results of Example 5 and Comparative Example 2 show that the preparation method of the highly dispersed conductive carbon black of the present application has a more obvious modification effect on the raw material oil with a higher impurity content, probably because the supercritical treatment not only achieves a better impurity removal effect, but also reduces the electrostatic adsorption between the carbon black mixtures during the post-treatment, further improving the post-treatment effect.

[0130] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0131] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the invention patent shall be subject to the appended claims, and the specification can be used to explain the content of the claims.

Claims

1. A preparation method of highly dispersed conductive carbon black, characterized in that, It includes the following steps: Wet granulate the furnace black powder to form a carbon black mixture; Perform supercritical treatment on the carbon black mixture to obtain highly dispersed conductive carbon black; The supercritical treatment includes: mixing the carbon black mixture with supercritical carbon dioxide under a pressure of 80 Mpa to 120 Mpa.

2. The preparation method of the highly dispersed conductive carbon black according to claim 1, characterized in that, The steps of the wet granulation include: Mix the furnace black powder and water to form an intermediate mixture; Mix the intermediate mixture with a binder to form the carbon black mixture.

3. The preparation method of the highly dispersed conductive carbon black according to claim 2, wherein, The mass ratio of the furnace black powder to the water is 1:(10 - 20); and / or The binder includes one or more of polyacrylic acid, polyvinyl ketone, and lignin; the mass ratio of the intermediate mixture to the binder is 1:(0.05 - 0.1).

4. The preparation method of the highly dispersed conductive carbon black according to claim 1, characterized in that, It also includes the step of post - treating the carbon black mixture after the supercritical treatment, and the post - treatment includes drying, desorption, and refining.

5. The preparation method of the highly dispersed conductive carbon black according to any one of claims 1 to 4, characterized in that, The preparation steps of the furnace black powder include: Mix the feedstock oil, air, and natural gas in a reaction furnace and carry out a cracking reaction to form the furnace black powder.

6. The preparation method of the highly dispersed conductive carbon black according to claim 5, characterized in that, Meet one or more of the following conditions: (1) The volume ratio of the air to the natural gas is (17 - 20):1; (2) The time of the cracking reaction is 30 ms to 60 ms; (3) The temperature of the cracking reaction is 1600 °C to 1800 °C; (4) The flow rate of the feedstock oil into the reaction furnace is 3000 kg / h to 3500 kg / h.

7. The preparation method of the highly dispersed conductive carbon black according to claim 5, characterized in that, When the ash content of the feedstock oil ≤ 0.03%, the supercritical treatment meets the following conditions: The treatment time of the supercritical treatment is 1 h to 6 h; The temperature of the supercritical treatment is 30 °C to 50 °C; The mixing rate of the supercritical treatment is 10 rpm to 60 rpm.

8. The preparation method of the highly dispersed conductive carbon black according to claim 5, characterized in that, When the ash content of the feedstock oil > 0.03%, the supercritical treatment meets the following conditions: The treatment time of the supercritical treatment is 6 h to 12 h; The temperature of the supercritical treatment is 50 °C to 80 °C; The mixing rate of the supercritical treatment is 20 rpm to 80 rpm.

9. A highly dispersible conductive carbon black, characterized in that, Prepared by using the preparation method of the highly dispersed conductive carbon black according to any one of claims 1 - 8.

10. A high-voltage cable, characterized in that, It includes a conductor, an insulating layer, and a semi - conductive shielding layer; the conductor is located inside the insulating layer, and the semi - conductive shielding layer is located on at least one surface of the insulating layer; the conductive filler of the semi - conductive shielding layer contains the highly dispersed conductive carbon black according to claim 9 or the highly dispersed conductive carbon black prepared by the preparation method according to any one of claims 1 - 8.

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