A preparation method for improving the tap density and particle size yield of carbide materials

Abstract

This invention discloses a method for preparing carbonized materials with improved tap density and particle size yield, comprising the following steps: mixing a dispersion of amino-grafted carbon fibers with pitch, removing organic solvents, granulating and shaping with raw coke to obtain intermediate particles, carbonizing the intermediate particles four times, and then shaping to obtain carbonized materials. This invention can improve the tap density and particle size yield of carbonized materials, which is beneficial for the later production of artificial graphite.

Description

Technical Field

[0001] This invention relates to the field of artificial graphite technology, and in particular to a method for preparing carbonized materials with improved tap density and particle size yield. Background Technology

[0002] Artificial graphite typically refers to a blocky solid material made by using raw material coke as aggregate and asphalt as binder, and through processes such as grinding, mixing, granulation, carbonization and graphitization. It is often used in the negative electrode material of lithium-ion batteries.

[0003] Tap density has a significant impact on the electrochemical properties of artificial graphite, and the tap density and particle size of materials in each step of granulation, carbonization, and graphitization all affect the tap density and production process of artificial graphite. Therefore, it is necessary to improve the performance of materials in each step. However, currently, the tap density of the material obtained in the carbonization stage is relatively low, and the particle size is generally large, resulting in a low particle size yield, which is not conducive to material shaping and production, nor to improving the tap density of artificial graphite. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, this invention proposes a high-performance artificial graphite, its preparation method and application. This invention can improve the tap density and particle size yield of carbonized materials, which is beneficial to the subsequent production of artificial graphite.

[0005] This invention proposes a method for improving the tap density and particle size yield of carbonized materials, comprising the following steps: mixing a dispersion of amino-grafted carbon fibers with asphalt, removing organic solvents, granulating and shaping with raw coke to obtain intermediate particles, carbonizing the intermediate particles four times, and then shaping to obtain carbonized materials.

[0006] Preferably, the solvent for the dispersion of amino-grafted carbon fibers is toluene.

[0007] Preferably, the dispersion of amino-grafted carbon fibers is mixed with asphalt at 140-160°C and 500-1000 rpm for 1-2 hours.

[0008] Preferably, the amino-grafted carbon fiber is a carbon fiber modified by grafting with an amino-containing silane coupling agent; the amino-grafted carbon fiber accounts for 0.5-1 wt% of the weight of the pitch.

[0009] The aforementioned amino-containing silane coupling agents can be γ-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, etc.

[0010] Preferably, the organic solvent is removed by heating at 80-90°C.

[0011] Preferably, the raw material coke is at least one of needle coke or petroleum coke; the asphalt is petroleum asphalt; and the granulation temperature is 600-650℃.

[0012] Preferably, the intermediate particles have a volatile matter content of 5-6 wt% and a tap density of 0.5-0.6 g / cm³. 3 ; intermediate particles with D0 ≥ 2μm, D 10 ≥7.5μm, D 50 14-17μm, D 90 ≤28μm, D 99 ≤48μm.

[0013] Preferably, four carbonization processes are carried out in the carbonization equipment, which has a rotary motor and 12 temperature zones.

[0014] Preferably, the temperatures of the first carbonization zones 1-12 are as follows: 180-220℃, 380-420℃, 640-660℃, 640-660℃, 640-660℃, 640-660℃, 640-660℃, 590-610℃, 540-560℃, 380-420℃, and 280-320℃.

[0015] The temperatures of the secondary carbonization zones 1-12 are as follows: 180-220℃, 380-420℃, 640-660℃, 740-760℃, 740-760℃, 740-760℃, 740-760℃, 690-710℃, 640-660℃, 480-520℃, and 280-320℃.

[0016] The temperatures of the three carbonization zones 1-12 are as follows: 180-220℃, 380-420℃, 640-660℃, 840-860℃, 840-860℃, 840-860℃, 840-860℃, 790-810℃, 740-760℃, 580-620℃, and 380-420℃.

[0017] The temperatures for the four carbonization stages 1-12 are as follows: 180-220℃, 380-420℃, 640-660℃, 840-860℃, 940-960℃, 940-960℃, 940-960℃, 890-910℃, 840-860℃, 680-720℃, and 480-520℃.

[0018] Preferably, the feeding frequency for each of the four carbonization processes is 10-20Hz, and the frequency of the rotary motor is 35-45Hz.

[0019] Adjusting the frequency of the rotary motor in the carbonization equipment can control the carbonization time in each temperature zone. The aforementioned carbonization equipment can be a rotary kiln, etc.

[0020] The carbonized material obtained above has D0≥2μm and D 10 ≥7.5μm, D 50 16-19μm, D 90 ≤35μm, D 99 ≤45μm, D 100 ≤55μm.

[0021] This invention involves four low-temperature carbonization processes, and adjusting the carbonization parameters for each process can reduce gas release during carbonization and promote material shrinkage. This, combined with carbon fibers, improves the material's density, tap density, and particle size yield.

[0022] Beneficial effects:

[0023] This invention uses a silane coupling agent to graft and modify carbon fibers, which improves the dispersibility of carbon fibers in asphalt. The grafted amino groups can bond with active groups such as carboxyl groups in the asphalt during mixing, further enhancing the bonding force. Furthermore, the carbon fibers form a complex chain-like network structure in the asphalt, which can suppress the volume expansion of intermediate particles during carbonization, reduce porosity, and increase density, thereby improving the tap density of the carbonized material and ensuring that the particle size meets requirements, thus improving particle size yield. In addition, this invention involves four low-temperature carbonization processes, adjusting the carbonization parameters for each process to reduce gas release during carbonization and promote material shrinkage. This, combined with the carbon fibers, improves the material's density, tap density, and particle size yield. After four carbonization processes, the material becomes dry, free of lumps, and has the required particle size, facilitating production. Detailed Implementation

[0024] The technical solution of the present invention will be described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0025] Example 1

[0026] A method for improving the tap density and particle size yield of carbonized materials includes the following steps:

[0027] A toluene dispersion of γ-aminopropyltriethoxysilane-modified carbon fiber was added to petroleum asphalt, heated to 150°C, stirred at 800 rpm for 1.5 h, and heated at 80-90°C for 2 days to remove organic solvents; wherein, the γ-aminopropyltriethoxysilane-modified carbon fiber accounted for 0.7 wt% of the weight of petroleum asphalt.

[0028] Then, needle coke is added and mixed thoroughly. Granulation and shaping are then carried out at 625℃ to obtain intermediate particles. The weight ratio of needle coke to petroleum asphalt is 8:2. The volatile matter content of the intermediate particles is 5.5 wt%, and the tapped density is 0.55 g / cm³. 3; intermediate particles with D0 ≥ 2μm, D 10 ≥7.5μm, D 50 14-17μm, D 90 ≤28μm, D 99 ≤48μm;

[0029] 5.0 tons of intermediate particles were added to a rotary kiln, which has a rotary motor and 12 temperature zones, and carbonized four times. The carbonized material was then shaped. The parameters of the four carbonization processes are shown in Table 1.

[0030] Example 2

[0031] A method for improving the tap density and particle size yield of carbonized materials includes the following steps:

[0032] A toluene dispersion of N-2-aminoethyl-3-aminopropyltrimethoxysilane-modified carbon fiber was added to petroleum asphalt, heated to 140°C, stirred at 1000 rpm for 1 hour, and heated at 80-90°C for 2 days to remove the organic solvent; wherein, the N-2-aminoethyl-3-aminopropyltrimethoxysilane-modified carbon fiber accounted for 0.5 wt% of the weight of petroleum asphalt.

[0033] Then, needle coke is added and mixed thoroughly. Granulation and shaping are then carried out at 650℃ to obtain intermediate particles. The weight ratio of needle coke to petroleum asphalt is 8:2. The volatile matter content of the intermediate particles is 5 wt%, and the tapped density is 0.5 g / cm³. 3 ; intermediate particles with D0 ≥ 2μm, D 10 ≥7.5μm, D 50 14-17μm, D 90 ≤28μm, D 99 ≤48μm;

[0034] 4.5 tons of intermediate particles were added to a rotary kiln, which has a rotary motor and 12 temperature zones, and carbonized four times. The carbonized material was then shaped. The parameters of the four carbonization processes are shown in Table 1.

[0035] Example 3

[0036] A method for improving the tap density and particle size yield of carbonized materials includes the following steps:

[0037] A toluene dispersion of γ-aminopropyltriethoxysilane-modified carbon fiber was added to petroleum asphalt, heated to 160°C, stirred at 500 rpm for 2 hours, and heated at 80-90°C for 2 days to remove organic solvents; wherein, the γ-aminopropyltriethoxysilane-modified carbon fiber accounted for 1 wt% of the weight of petroleum asphalt.

[0038] Then, needle coke is added and mixed thoroughly. Granulation and shaping are then carried out at 600℃ to obtain intermediate particles. The weight ratio of needle coke to petroleum asphalt is 8:2. The volatile matter content of the intermediate particles is 6 wt%, and the tapped density is 0.6 g / cm³. 3 ; intermediate particles with D0 ≥ 2μm, D 10 ≥7.5μm, D 50 14-17μm, D 90 ≤28μm, D 99 ≤48μm;

[0039] 4.7 tons of intermediate particles were added to a rotary kiln, which has a rotary motor and 12 temperature zones, and carbonized four times. The carbonized material was then shaped. The parameters of the four carbonization processes are shown in Table 1.

[0040] Comparative Example 1

[0041] The carbon fiber was modified without the addition of γ-aminopropyltriethoxysilane, and was directly granulated by mixing petroleum pitch and needle coke, with the other steps being the same as in Example 1.

[0042] Comparative Example 2

[0043] A carbonization process was carried out, and the parameters for the carbonization are shown in Table 1.

[0044] Comparative Example 3

[0045] Carbon fibers were modified without the addition of γ-aminopropyltriethoxysilane, and were directly granulated by mixing petroleum pitch and needle coke, and only one carbonization was performed. The carbonization parameters are shown in Table 1.

[0046] Comparative Example 4

[0047] Carbon fibers were modified without the addition of γ-aminopropyltriethoxysilane, and were directly granulated by mixing petroleum pitch and needle coke, and only one carbonization was performed. The carbonization parameters are shown in Table 1.

[0048] Table 1. Carbonization parameters of Examples 1-3 and Comparative Examples 1-4

[0049]

[0050]

[0051] Six parallel experiments were conducted in each group, and the performance results of the carbonized materials obtained in each group were statistically analyzed, as shown in Table 2. The results are average values.

[0052] Table 2 Detection Results

[0053]

[0054] Note: The particle size requirement for carbonized materials is: D0 ≥ 2μm, D 10 ≥7.5μm, D50 16-19μm, D 90 ≤35μm, D 99 ≤45μm, D 100 ≤55μm.

[0055] As can be seen from Table 2, the addition of carbon fiber and the combination of a suitable carbonization process in this invention result in carbonized materials with high tap density and good particle size yield.

[0056] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A production method for improving the tap density and particle size yield of a carbide material, characterized by, The method comprises the following steps: mixing a dispersion of amino-grafted carbon fibers with pitch, removing organic solvents, granulating and shaping raw coke to obtain intermediate particles, carbonizing the intermediate particles four times, and then shaping the carbonized material; The amino-grafted carbon fibers are carbon fibers modified by a silane coupling agent containing amino groups; the amino-grafted carbon fibers account for 0.5-1wt% of the pitch. The intermediate granules have a volatile content of 5-6 wt%, a tapped density of 0.5-0.6 g / cm3 3 ; the intermediate granules have a D0≥ 2 μm, a D 10 7.5 μm, a D 50 14-17 μm, a D 90 ≤ 28 μm, a D 99 ≤ 48 μm; The four times of carbonization are performed in a carbonization device with a rotary motor and 12 temperature zones. The temperatures of the 1st carbonization in the 1st-12th temperature zones are 180-220℃, 380-420℃, 640-660℃, 640-660℃, 640-660℃, 640-660℃, 640-660℃, 640-660℃, 590-610℃, 540-560℃, 380-420℃, and 280-320℃, respectively. The temperatures of the 2nd carbonization in the 1st-12th temperature zones are 180-220℃, 380-420℃, 640-660℃, 740-760℃, 740-760℃, 740-760℃, 740-760℃, 740-760℃, 690-710℃, 640-660℃, 480-520℃, and 280-320℃, respectively. The temperatures of the 3rd carbonization in the 1st-12th temperature zones are 180-220℃, 380-420℃, 640-660℃, 840-860℃, 840-860℃, 840-860℃, 840-860℃, 840-860℃, 790-810℃, 740-760℃, 580-620℃, and 380-420℃, respectively. The temperatures of the 4th carbonization in the 1st-12th temperature zones are 180-220℃, 380-420℃, 640-660℃, 840-860℃, 940-960℃, 940-960℃, 940-960℃, 940-960℃, 890-910℃, 840-860℃, 680-720℃, and 480-520℃, respectively. The feeding frequency of the 4th carbonization is 10-20Hz, and the frequency of the rotary motor is 35-45Hz.

2. The production method for improving the tap density and the particle size yield of a carbide material according to claim 1, characterized by, The solvent of the dispersion of the amino-grafted carbon fibers is toluene.

3. The production method for improving the tap density and the particle size yield of a carbide material according to claim 1 or 2, characterized by, The dispersion of the amino-grafted carbon fibers is mixed with the pitch at 140-160℃ and stirred at a speed of 500-1000rpm for 1-2h.

4. The production method for improving the tap density and the particle size yield of a carbide material according to claim 1 or 2, characterized by, The organic solvents are removed by heating at 80-90℃.

5. The production method for improving the tap density and the particle size yield of a carbide material according to claim 1 or 2, characterized by, The raw coke is at least one of needle coke or petroleum coke; the pitch is petroleum pitch; and the granulating temperature is 600-650℃.

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