Method for post-treating carbon black and carbon black post-treated thereby

Abstract

The present invention relates to a method for post-treating carbon black and the carbon black post-treated thereby, and more particularly to a method for post-treating wet-pelleted furnace carbon black and the carbon black post-treated thereby and uses thereof.

Description

[Technical Field]

[0001] The present invention relates to a method for post-treating carbon black and carbon black post-treated thereby, and more particularly to a method for post-treating wet-pelleted furnace carbon black, a type of carbon black, and carbon black post-treated thereby. [Background technology]

[0002] Carbon black is an aggregate of extremely fine spherical particles obtained by incomplete combustion of hydrocarbons or carbon-containing compounds. Carbon black forms primary particles in a reactor, which then fuse together to form grape-like aggregates. Carbon black can be broadly categorized into acetylene carbon black and furnace carbon black. Furnace carbon black has the advantage of being inexpensive, but its disadvantage is that it is difficult to achieve high crystallinity compared to acetylene carbon black.

[0003] Carbon black's physical properties affect the quality of materials it is used in, including crystallinity, specific surface area, structure, and particle size, and the properties can be adjusted through various post-treatments. Carbon black is used in a variety of fields, including industrial paints, coating compositions, and various printed materials. Because of its electrical properties, it can be used as a conductive material in lithium-ion secondary batteries, and if high crystallinity is ensured, it can be used as a catalyst support for fuel cells.

[0004] Meanwhile, carbon black powder or carbon black granules (pellets or beads) are known to be used to manufacture carbon black for industrial and commercial purposes. Carbon black granules can be divided into wet granulated and dry granulated forms.

[0005] Carbon black powder has excellent dispersibility in various solvents, but has the disadvantage of low bulk density, which reduces productivity during processes such as heat treatment. On the other hand, carbon black granules have the advantage of high bulk density, but have the disadvantage of being larger in average particle size than carbon black powder and less dispersible, making them unsuitable for slurry production.

[0006] Carbon black has been used as a material for secondary batteries, which have become more advanced and diversified in recent years. However, there is a need to continuously develop technologies that can improve the physical properties of carbon black depending on the application and efficiently realize the improvement in the properties from the viewpoint of processing. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide a method for efficiently post-treating carbon black having excellent physical properties in an in-process manner using wet-granulated furnace carbon black, and to provide carbon black post-treated thereby.

[0008] An object of the present invention is to provide high-quality carbon black produced using wet-granulated furnace carbon black, which has reduced surface resistance and a reduced content of impurities, and a conductive material for a secondary battery containing the same.

[0009] An object of the present invention is to provide high-quality carbon black that is produced using wet-granulated furnace carbon black and has high crystallinity and a reduced content of impurities, and a catalyst support for fuel cells containing the same.

[0010] The objects of the present invention are not limited to those mentioned above, and other objects and advantages of the present invention not mentioned above can be understood from the following description and can be more clearly understood from the examples of the present invention. Furthermore, it can be easily understood that the objects and advantages of the present invention can be achieved by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0011] In order to achieve the above object, one aspect of the present invention provides a method for post-treating carbon black, including: (a) preparing wet-granulated furnace carbon black; (b) heat-treating the furnace carbon black in a furnace at a high temperature of 1200°C or higher; (c) continuously transferring the high-temperature heat-treated furnace carbon black to a pulverizer; and (d) pulverizing the furnace carbon black transferred to the pulverizer to obtain carbon black having an average particle diameter of 20 μm or less.

[0012] The produced carbon black may have an average particle size of 15 μm or less.

[0013] An atmospheric gas can be introduced during the high-temperature heat treatment in the above step (b).

[0014] The atmospheric gas may include one or more of nitrogen (N2) gas and argon (Ar) gas.

[0015] The produced carbon black may have a total content of metal impurities of 100 ppm or less.

[0016] The heat treatment temperature may be 2000 to 2500° C., and the produced carbon black may be highly crystalline carbon black having an Lc of 4.0 nm or more.

[0017] The heat treatment temperature may be 1000 to 1500° C., and the produced carbon black may be conductive carbon black.

[0018] The transfer in step (c) is carried out by a fluidized medium; The transfer of the furnace carbon black by the fluidizing medium and the separation of the fluidizing medium from the transferred furnace carbon black may be carried out simultaneously.

[0019] The pulverizer in the step (d) can be any of a high-speed mixer, a ball mill, and an air jet mill.

[0020] According to another aspect of the present invention, there is provided carbon black that has been post-treated by the method for post-treating carbon black according to an aspect of the present invention.

[0021] According to another aspect of the present invention, there is provided a conductive material for a lithium ion secondary battery, including carbon black post-treated by the method for post-treating carbon black according to an aspect of the present invention.

[0022] According to another aspect of the present invention, there is provided a catalyst support for a fuel cell, which includes carbon black that has been post-treated by the method for post-treating carbon black according to an aspect of the present invention. [Effects of the Invention]

[0023] According to the present invention, wet-granulated furnace carbon black can be used to provide carbon black with excellent physical properties that can be post-treated in a process- and cost-effective manner.

[0024] The wet-granulated furnace carbon black used in the carbon black production method of the present invention has a high volume density, which allows for a significant increase in the loading amount in the carbon black production process, and since the method includes a series of steps that allow for continuous carbon black production, it can significantly improve productivity.

[0025] The carbon black post-treated by the carbon black post-treatment method of the present invention has the advantage that the content of metal impurities and the content of sulfur can be reduced, while at the same time, the surface resistance can be reduced or the crystallinity can be significantly increased, making it suitable for obtaining carbon black that can be used in various applications for products that require high quality.

[0026] The above-mentioned effects and specific effects of the present invention will be described in conjunction with the following description of the preferred embodiment of the invention. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a simplified flow diagram of a method for producing carbon black according to one embodiment of the present invention. [Figure 2] FIG. 1 is a SEM image of carbon black in Reference Example 1 of the present invention. [Figure 3] FIG. 1 shows an SEM image of the carbon black of Example A of the present invention. [Figure 4] FIG. 1 shows an SEM image of the carbon black of Comparative Example A of the present invention. [Figure 5] FIG. 1 shows an SEM image of the carbon black of Comparative Example B of the present invention. [Figure 6] FIG. 1 is a photograph showing an actual electrode coated with the carbon black slurry of Example A of the present invention. [Figure 7] FIG. 1 is a photograph showing an actual electrode coated with the carbon black slurry of Comparative Example A of the present invention. [Figure 8a]FIG. 2 is a SEM image of the cross section of an electrode produced using the carbon black slurry of Example A of the present invention. [Figure 8b] FIG. 2 is a diagram showing a mapping image obtained by SEM EDS analysis of a cross section of an electrode prepared using the carbon black slurry of Example A of the present invention. [Figure 9a] FIG. 2 is a SEM image of the cross section of an electrode prepared using the carbon black slurry of Comparative Example A of the present invention. [Figure 9b] FIG. 1 is a diagram showing a mapping image obtained by SEM EDS analysis of a cross section of an electrode prepared using the carbon black slurry of Comparative Example A of the present invention. [Figure 10a] FIG. 2 is a SEM image of the surface of an electrode prepared using the carbon black slurry of Example A of the present invention. [Figure 10b] FIG. 2 is a diagram showing a mapping image obtained by SEM EDS analysis of the surface of an electrode prepared using the carbon black slurry of Example A of the present invention. [Figure 11a] FIG. 2 is a SEM image of the surface of an electrode prepared using the carbon black slurry of Comparative Example A of the present invention. [Figure 11b] FIG. 1 is a diagram showing a mapping image obtained by SEM EDS analysis of the surface of an electrode prepared using the carbon black slurry of Comparative Example A of the present invention. [Figure 12] FIG. 1 is a SEM image of an electrode coated with the carbon black slurry of Example X of the present invention. [Figure 13] FIG. 1 is a SEM image of an electrode coated with the carbon black slurry of Comparative Example X of the present invention. [Figure 14] FIG. 1 illustrates an example of a method for analyzing the average particle size of carbon black particles by taking SEM images. DETAILED DESCRIPTION OF THE INVENTION

[0028] The above-mentioned objects, features and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the technical concept of the present invention.

[0029] In describing the present invention, if a detailed description of known techniques relating to the present invention is deemed to obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings are used to indicate the same or similar components.

[0030] When elements in this specification are referred to as "comprising," "having," "consisting of," "arranged," "comprising," etc., other parts can be added unless "only" is used. When elements are expressed in the singular, this also includes the plural, unless otherwise expressly stated.

[0031] When interpreting the elements in this specification, they are interpreted as including a margin of error unless otherwise explicitly stated.

[0032] The present invention will be described in more detail below.

[0033] The carbon black post-treatment method of the present invention is characterized by the use of wet-pelletized furnace carbon black. As described above, wet-pelletized furnace carbon black has drawbacks such as low dispersibility and difficulty in preparing a slurry. Despite its cost and process advantages, it is not used in the production of carbon black for battery materials. In fact, carbon black powder is used in the production of industrial carbon black.

[0034] As a result of extensive research, the inventors have found that while wet-pelletized furnace carbon black has the advantages of high volume density, high process loading, and improved productivity, its drawback of poor dispersibility can be overcome by post-treating the carbon black by adjusting the heat treatment and pulverization conditions. Specifically, the present inventors experimentally identified an optimal carbon black particle size that significantly improves dispersibility during slurry preparation. Furthermore, the present inventors have found that post-treated carbon black can be made environmentally friendly by increasing its purity and reducing its sulfur content, and can also ensure various physical properties, such as increased crystallinity or reduced surface resistance to provide conductivity, depending on the application of the post-treated carbon black.

[0035] Specifically, as shown in FIG. 1, a method for post-treating carbon black according to one embodiment of the present invention may include the following steps: (a) providing a wet granulated furnace carbon black; (b) subjecting the furnace carbon black to a high-temperature heat treatment in a furnace at a temperature of 1200°C or higher; (c) continuously transferring the high-temperature heat-treated furnace carbon black to a pulverizer; and (d) pulverizing the furnace carbon black transferred to the pulverizer to obtain the final post-treated carbon black.

[0036] In particular, the average particle size of the carbon black finally obtained by the carbon black post-treatment method of the present invention is preferably, for example, 20 μm or less, and more preferably 15 μm or less, from the viewpoint of improving dispersibility. Since a smaller particle size of the post-treated carbon black is more advantageous, the lower limit of the average particle size is not particularly specified. Carbon black having an average particle size within the above range has excellent dispersibility in a solvent and can improve processability during slurry production.

[0037] The wet-granulated furnace carbon black used in the present invention in step (a) is wet-pelletized in a pelletizing machine and is not particularly limited as long as it is a furnace carbon black used in the technical field. For example, the wet-granulated furnace carbon black may have an average particle size of about 0.25 to 2.0 mm and an average volume density of about 0.2 to 0.3 g / cm. 3 However, it is not necessarily limited to this.

[0038] Step (b) is a heat treatment step for modifying the physical properties of carbon black. By performing heat treatment at a high temperature of 1200°C or higher, impurities such as metals can be removed and the purity can be increased.

[0039] In the high-temperature heat treatment in step (b), an atmospheric gas may be introduced to more effectively remove impurities. The atmospheric gas may include at least one of nitrogen (N2) gas and argon (Ar) gas, and preferably nitrogen gas.

[0040] According to one embodiment of the present invention, the purity of the post-treated carbon black can be increased, and the content of metal impurities and / or sulfur can be reduced.

[0041] According to one embodiment of the present invention, the total content of metal impurities in the post-treated carbon black may be, for example, 100 ppm or less, for example, 90 ppm or less, for example, 80 ppm or less, for example, 70 ppm or less, for example, 60 ppm or less, for example, 50 ppm or less, for example, 40 ppm or less, for example, 30 ppm or less, for example, 20 ppm or less, or for example, 10 ppm or less.

[0042] The metal impurities are metal elements that may be contained in carbon black, and specifically may include Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Sn, Sr, Ti, V, and Zn, and can be measured by inductively coupled plasma-optical emission spectroscopy (ICP-OES).

[0043] Furthermore, the sulfur content of the post-treated carbon black is not particularly limited and can be significantly reduced compared to the furnace carbon black before post-treatment. The specific sulfur content can be adjusted depending on the application of the post-treated carbon black.

[0044] According to one embodiment of the present invention, the sulfur content of the post-treated carbon black may be, for example, 3000 ppm or less, for example, 2000 ppm or less, for example, 1000 ppm or less, or for example, 500 ppm or less.

[0045] In addition, by adjusting the heat treatment temperature in the heat treatment step (b), the surface properties of the carbon black can be adjusted depending on the application of the carbon black.

[0046] According to one embodiment of the present invention, in order to reduce the surface resistance compared to before the post-treatment and ensure conductivity, the heat treatment temperature in the above step (b) is preferably 1200 to 1800°C, more preferably 1200 to 1500°C.

[0047] On the other hand, in order to increase the crystallinity of the carbon black, the heat treatment temperature in step (b) is preferably 2000 to 2500° C., more preferably 2300 to 2500° C. As an index for confirming high crystallinity of carbon black, a large Lc value, which is the microcrystal size, is particularly preferred.

[0048] Specifically, the carbon black post-treated according to the present invention may have an Lc of, for example, 4.0 nm or more, for example, an Lc of 5.0 nm or more, or for example, an Lc of 6.0 nm or more. If the Lc is 4.0 nm or more, it can be evaluated as having very high crystallinity. The carbon black post-treatment method of the present invention has the advantage of being able to produce highly crystalline carbon black.

[0049] In step (c), the heat-treated furnace carbon black is transferred to a pulverizer for pulverization. In the present invention, transfer can be performed using a fluidized medium. The fluidized medium is not particularly limited, but may include air for process convenience. Furthermore, by simultaneously transferring the furnace carbon black using the fluidized medium and separating the fluidized medium from the transferred furnace carbon black, the carbon black can be continuously post-treated, thereby increasing process productivity. Furthermore, in the carbon black post-treatment method of the present invention, the loading amount per post-treatment process can be significantly increased by using wet-granulated carbon black. Furthermore, even when a large loading amount (input amount) is post-treated at one time, the desired physical properties of the carbon black can be maintained. Therefore, these process advantages can be simultaneously realized, resulting in increased process convenience and productivity.

[0050] As an apparatus for continuously transferring and separating the heat-treated furnace carbon black, for example, a pulse jet bag filter apparatus is preferably used. This apparatus has the advantage that it can continuously transfer the furnace carbon black using air as a medium under vacuum and automatically separates the air after transfer, thereby allowing the process to be carried out efficiently and continuously.

[0051] In step (d), the heat-treated furnace carbon black is pulverized, and the average particle size of the pulverized carbon black is preferably 20 μm or less, more preferably 15 μm or less, as described above. The pulverization method or apparatus is not particularly limited, but examples of pulverizers that can be used include high-speed mixers, ball mills, and air jet mills. From the viewpoint of ease of pulverization, an air jet mill is preferably used.

[0052] The carbon black of the present invention that has been post-treated as described above can be suitably used in products that require high-quality carbon black, such as conductive materials for lithium-ion secondary batteries or catalyst supports for fuel cells. [Example]

[0053] The present invention will be described in more detail below with reference to examples and experimental examples. However, the following examples and experimental examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

[0054] <Example> PART 1 - Heat Treatment Process Test: Examples 1 to 8 and Comparative Examples 1 to 3 Wet-pelletized furnace carbon black (DC3501 (OCI)) or powder furnace carbon black (DC3501 (OCI)) was prepared and heat-treated in a batch mode in a heat resistance furnace. Specifically, the carbon black was loaded into a graphite crucible at approximately 70 vol%. Heat treatment was performed for 1 hour at a temperature increase rate of 5°C / min to the maximum temperature listed in Table 1, with nitrogen or argon gas introduced as the atmospheric gas.

[0055] [Table 1]

[0056] The physical properties of each of the heat-treated carbon blacks in Examples 1 to 8 and Comparative Examples 1 to 3 were measured according to the following (1) to (5), and are shown in Table 2 below.

[0057] (1) Specific surface area The specific surface area was analyzed by nitrogen adsorption using the Brunauer-Emmett-Teller (BET) equation (analysis equipment: Micromeritics ASAP2460).

[0058] (2) Crystallinity, Lc(200) : X-ray diffraction (XRD) analysis was performed (analysis equipment: Panalytical Empyrean Alpha1) and the calculation was performed using the Scherrer equation in the following [Equation 1].

[0059] [Formula 1] Scherrer equation: Lc=0.89λ / (Bc Cos θ)

[0060] λ = Wavelength of anode, 1.540998 (constant) Bc=FWHM (Full Width at Half Maximum) θ = XRD002 peak position (measured value)

[0061] (3) Measurement of metal impurity content : Inductively Coupled Plasma-Optical Emission Spectrometer (Analysis equipment: Inductively Coupled Plasma-Optical Emission Spectrometer)

[0062] (4) Measurement of sulfur content :Elemental analysis method (Analysis equipment: LECO CS-200 analyzer)

[0063] (5) Surface resistance The post-treated carbon black was dispersed in an isopropyl alcohol (IPA) solvent at a concentration of about 10 wt% to prepare a slurry. The slurry was then coated onto an aluminum (Al) electrode plate with a doctor blade to a thickness of about 50 μm, and dried at about 100°C for 1 hour to prepare an electrode. The surface resistance of the electrode was measured using a resistance tester (analysis equipment: Mitsubishi MCP-T610).

[0064] [Table 2]

[0065] As can be seen from Tables 1 and 2, the Lc value, which indicates crystallinity, increased significantly with increasing heat treatment temperature, and the content of metal impurities and sulfur decreased. It was also found that using nitrogen gas as the ambient gas during the heat treatment process significantly reduced the content of metal impurities. This is presumably because argon gas is a monoatomic Ar molecule, while nitrogen is a diatomic N2 molecule. Therefore, at high temperatures, the nitrogen gas dissociates into nitrogen ions, which then bond with the metal impurities, resulting in the metal elements being gasified and released. Furthermore, compared to the use of conventional powdered carbon black, the use of wet-pelletized carbon black did not result in any change in physical properties due to the heat treatment temperature. This suggests that by adjusting the heat treatment conditions, even wet-pelletized carbon black, which has not previously been used as a battery material, can be heat-treated to achieve properties equivalent to those of powdered carbon black.

[0066] Furthermore, after forming a slurry using heat-treated carbon black and coating it, it was confirmed that the surface resistance value decreased when the heat treatment temperature was in the range of approximately 1200 to 1500°C, but it was also found from the experiment that the surface resistance value actually increased when the heat treatment temperature exceeded 1500°C.

[0067] The most important physical property of carbon black for use as a conductive material in lithium-ion secondary batteries is conductivity (electrical conductivity), and low surface resistance is required. Therefore, it was confirmed through experiments that a heat treatment temperature of 1200 to 1500°C is suitable for obtaining conductive carbon black.

[0068] Furthermore, for carbon black used as a catalyst support in fuel cells, durability is a more important physical property than electrical conductivity. Therefore, the above experimental results confirmed that carbon black with a high level of crystallinity, i.e., Lc of 4 nm or more, requires a heat treatment temperature of 2000°C or higher.

[0069] PART 2: Testing of slurries for lithium-ion secondary batteries An experiment was conducted to confirm the manufacturing state of the slurry for lithium ion secondary batteries, and the relationship between the average particle size of the post-treated carbon black after pulverization and the manufacturing state of the slurry.

[0070] Reference Example 1: The above Comparative Example 2 was used as Reference Example 1 to compare the performance with powder carbon black.

[0071] Example A: The carbon black heat-treated in Example 2 above was pulverized using an air jet mill to an average particle size of 10.8 μm, and this was used as Example A.

[0072] Comparative Example A: The material heat-treated in Example 2 was used as is (without being crushed) to prepare Comparative Example A.

[0073] Comparative Example B: The carbon black heat-treated in Example 2 was pulverized to an average particle size of 25.2 μm using a high-speed stirring pulverizer, which is a type of high-speed mixer.

[0074] <Measurement of average particle size> The average particle size was determined by analyzing approximately 100 carbon black particles in an SEM image observed using a scanning electron microscope (SEM), and is shown in Table 3 below. An example of a method for measuring the average particle size is shown in Figure 14.

[0075] SEM images were taken using a scanning electron microscope for each of Reference Example 1, Example A, Comparative Example A, and Comparative Example B, and are shown in FIGS.

[0076] <Coating properties of slurry for lithium-ion batteries and evaluation of electrodes> Preparation of Slurry: Slurries were prepared using the carbon blacks of Reference Example 1, Example A, Comparative Example A, and Comparative Example B by the following method, and the preparation state of the slurries was visually evaluated. The results are shown in Table 3 below.

[0077] NCM523 (cathode active material): Carbon black (conductive material): PVDF (binder) were mixed at a ratio of 95:2.5:2.5 (by weight), and NMP was used as the solvent to prepare a 50 wt% slurry solution based on the solid content. The slurry was dispersed at room temperature for approximately 30 minutes using a Thinky mixer.

[0078] Electrode fabrication: The slurry was coated onto an Al (aluminum) electrode plate with a doctor blade to a thickness of approximately 50 to 60 μm, and then dried for approximately 3 hours at 80° C. The dried electrode was then compressed with two rolls and further dried in a vacuum atmosphere at a temperature of approximately 100° C. for 12 hours to fabricate a cathode.

[0079] [Table 3]

[0080] Actual photographs of the slurries coated on the electrodes for Example A and Comparative Example A are shown in FIGS. 6 and 7, respectively.

[0081] For each of Example A and Comparative Example A, SEM images of the electrode cross sections were observed using a scanning electron microscope, and are shown in FIGS. 8(a) and 9(a), respectively. SEM EDS analysis using the SEM images revealed that only the carbon components (green or mint colored areas) representing carbon black were mapped, and these are shown in FIGS. 8(b) and 9(b), respectively.

[0082] For each of Example A and Comparative Example A, the electrode surface was observed using a scanning electron microscope (SEM) images, which are shown in FIGS. 10(a) and 11(a), respectively. SEM EDS analysis using the SEM images revealed that only the carbon components (green or mint colored areas) representing carbon black were mapped, which are shown in FIGS. 10(b) and 11(b), respectively.

[0083] Furthermore, as can be seen from the SEM images taken during the electrode manufacturing evaluation and the analysis results shown in Figures 2 to 11, when sufficiently pulverized carbon black was used, as in Example A, the slurry applicability (coatability) was good, and it was also confirmed that the dispersibility of the carbon black was high on the cross section and surface of the actually manufactured electrode.

[0084] For reference, the high-speed stirring pulverizer used in Comparative Example B is based on the principle that the carbon black is pulverized into powder by physical collision of the SUS blade with the blade at high speed. The collision with the blade at high speed makes it highly likely that the carbon black will be contaminated with metal impurities such as Fe and Ni. In addition, heat generated during operation makes it difficult to operate for long periods of time, and although the particle size was small, it was still larger than the level of powdered carbon black (see Reference Example).

[0085] On the other hand, air jet mills use high-pressure air to pulverize carbon black, so there is very little risk of contamination with metal impurities. Furthermore, they have the advantage of not generating heat and being able to operate for long periods of time. Furthermore, they are suitable for pulverizing carbon black to the powder level.

[0086] PART 3: Testing of fuel cell slurries An experiment was conducted to confirm the manufacturing state of the slurry for fuel cells, and the relationship between the average particle size of the post-processed carbon black after pulverization and the manufacturing state of the slurry.

[0087] Reference Example 2: The above Comparative Example 3 was used in Reference Example 2 to compare the performance with powder carbon black.

[0088] Example X: The carbon black heat-treated in Example 4 was pulverized using an air jet mill to an average particle size of 13.2 μm, and this was used as Example A.

[0089] Comparative Example X: The material heat-treated in Example 4 was used as is (without being crushed) to prepare Comparative Example X.

[0090] Comparative Example Y: The carbon black heat-treated in Example 4 was pulverized to an average particle size of 21.2 μm using a high-speed stirring pulverizer, which is a type of high-speed mixer.

[0091] <Measurement of average particle size> The average particle size is the average value obtained by analyzing about 100 carbon black particles in an SEM image observed with a scanning electron microscope (SEM), and is shown in Table 4 below.

[0092] <Evaluation of Coating Properties of Fuel Cell Anode Slurry> Preparation of Slurry and Coating: Using the carbon blacks of Reference Example 2, Example X, Comparative Example X, and Comparative Example Y as catalyst supports, slurries were prepared by the following method, and the preparation state of the slurries was visually evaluated. The results are shown in Table 4 below.

[0093] Ionomer and carbon black were mixed at a ratio of 50:50 (by weight) and a solvent was prepared by mixing n-butanol and DI-water at a ratio of 50:50 (by weight) to prepare a 10 wt% slurry solution based on solid content. The slurry was dispersed at room temperature for approximately 30 minutes using an Ultra-sonic.

[0094] Slurry coating: The slurry was coated onto a PTFE film with a doctor blade to a thickness of about 10 to 15 μm, and then dried at 40° C. for about 15 minutes to complete the coating of the slurry for a fuel cell anode electrode.

[0095] [Table 4]

[0096] For Example X and Comparative Example X, SEM images of the slurries coated on the electrodes taken by a scanning electron microscope are shown in Figures 12 and 13, respectively. However, as can be seen from Figures 12 and 13, since the slurry is mostly composed of carbon black, the SEM images do not clearly distinguish the slurry coating properties. However, with the naked eye, some unevenness can be observed on the surface, and it can be confirmed that the surface of the slurry coating of Example X is smoother and better dispersed than that of Comparative Example X.

[0097] Although the examples of the present specification have been described in detail above, the present specification is not necessarily limited to these examples, and various modifications can be made within the scope of the technical concept of the present specification. Therefore, the examples disclosed in the present specification are intended to illustrate, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these examples. Therefore, the above-described examples should be understood to be illustrative in all respects and not limiting. The present specification and the scope of protection of the present invention should be interpreted based on the claims, and any technical concept within the scope equivalent thereto should be interpreted as being included in the scope of the present specification and the present invention.

Claims

1. (a) providing a wet granulated furnace carbon black; (b) subjecting the furnace carbon black to a high-temperature heat treatment in a furnace at a temperature of 1200°C or higher; (c) continuously transferring the high-temperature heat-treated furnace carbon black to a pulverizer; and (d) pulverizing the furnace carbon black transferred to the pulverizer to obtain carbon black having an average particle diameter of 20 μm or less; Including, Carbon black post-treatment method.

2. The average particle size of the produced carbon black is 15 μm or less. The method for post-treating carbon black according to claim 1.

3. In the high-temperature heat treatment in the step (b), an atmospheric gas is introduced. The method for post-treating carbon black according to claim 1.

4. The atmospheric gas is nitrogen (N ２ ) gas and argon (Ar) gas, The method for post-treating carbon black according to claim 3.

5. The carbon black produced has a total content of metal impurities of 100 ppm or less. The method for post-treating carbon black according to claim 1.

6. the heat treatment temperature is 2000 to 2500°C, The produced carbon black is a highly crystalline carbon black having an Lc of 4.0 nm or more. The method for post-treating carbon black according to claim 1.

7. the heat treatment temperature is 1000 to 1500°C, The carbon black produced is conductive carbon black. The method for post-treating carbon black according to claim 1.

8. The transfer in step (c) is carried out by a fluid medium; The furnace carbon black is transported by the fluidized medium and the fluidized medium is separated from the transported furnace carbon black simultaneously. The method for post-treating carbon black according to claim 1.

9. The pulverization in the step (d) is carried out using any one of a high-speed mixer, a ball mill, and an air jet mill. The method for post-treating carbon black according to claim 1.

10. Carbon black post-treated by the post-treatment method according to any one of claims 1 to 9. Carbon black.

11. The post-treated carbon black according to any one of claims 1 to 9 is included. Conductive material for lithium-ion secondary batteries.

12. The post-treated carbon black according to any one of claims 1 to 9 is included. Catalyst support for fuel cells.

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