Method for preparing high-graphite carbon electrode by using waste auxiliary graphite

Abstract

The invention provides a method for preparing a high-graphite carbon electrode from waste auxiliary graphite and the carbon electrode. The method comprises the steps of crushing, screening, burdening, mixing, forming and roasting. In the crushing step, the waste auxiliary graphite is crushed and ground into powder; in the screening step, the crushed waste auxiliary graphite powder is screened into small-particle aggregates with the particle size of 2-6 mm and large-particle aggregates with the particle size of 6-10 mm; the preparation method comprises the following steps: mixing the small-particle aggregate and the large-particle aggregate according to equal mass to form waste auxiliary graphite scraps, and preparing the waste auxiliary graphite scraps, electrically calcined anthracite, high-quality graphite scraps, calcined petroleum coke and modified asphalt according to the mass ratios of 20-30%, 5-10%, 30-35%, 10-15% and 18-22%. And the requirements of high-quality and high-graphite carbon electrodes can be completely met.

Description

Technical Field

[0001] The invention relates to the technical field of large-diameter carbon electrode preparation, and in particular to a method for preparing a high-graphite carbon electrode by using waste auxiliary graphite and a carbon electrode. Background Art

[0002] 202320579486.3 A double-layer crucible loading structure for a graphitization furnace. This patented technology is a device used in the process of preparing graphite negative electrode materials for batteries. The device is a graphitized crucible. The material to be graphitized is loaded into the crucible. Since the impurity content requirements of the negative electrode materials for batteries are very strict, the crucible is also made of graphitized material, that is, a graphite crucible. Not only that, in order to ensure that the temperature of the material in the crucible reaches the set requirements during the graphitization process, the graphite crucible requires good thermal conductivity, that is, to ensure that the heat of the external resistor material is quickly transferred to the inside of the crucible after heating, and at the same time, the airtightness is excellent to prevent the impurity gas in the resistor material from entering the crucible and polluting the material. For this reason, when the crucible is made, the raw materials used are required to have a finer particle size to ensure airtightness, and at the same time, it is made of graphite material with good conductivity. The crucible is usually scrapped after being used several times and cannot be used again for the preparation of graphitized negative electrode materials.

[0003] In the preparation process of the carbon electrode of the present invention, in order to reduce the resistivity of the finished carbon electrode, some high-quality graphite scraps are added to the raw materials. The graphite scraps are usually ordinary graphite electrodes, high-power graphite electrodes or ultra-high-power graphite electrodes after graphitization, or graphite cathode blocks, high-purity graphite product scraps or process waste. The raw materials of these material products are all selected from high-quality graphite raw materials, and the preparation process is complicated; and the amount of such scraps is limited, and its price is also relatively high, which undoubtedly makes the cost of the original ingredients of the present invention high.

[0004] Although there are also technical proposals to apply the waste auxiliary graphite formed after the crucible in the background technology is crushed to the raw material ingredients of the carbon electrode of the present invention, there are still many technical problems. Although the crucible for producing graphite negative electrode materials in the background technology is also made of graphite material and has undergone a 2200°C graphitization process, its resistivity is relatively excellent, but since it is originally designed to avoid the external atmosphere from entering the crucible during the graphitization of the negative electrode material, it uses a material with a smaller particle size. In addition, it has undergone multiple graphitizations, resulting in serious powder ash in the internal material, making this part of the waste auxiliary graphite small in particle size and relatively loose. If it is directly applied to the raw materials of the carbon electrode, the strength of the carbon electrode will be reduced. Summary of the invention

[0005] In view of the above defects, the present invention proposes a method for preparing a high-graphite carbon electrode using waste auxiliary graphite, comprising the following steps: Crushing: First crush or grind the waste auxiliary graphite into powder; Screening: The crushed waste auxiliary graphite powder is screened into small particle aggregates of 2 to 6 mm and large particle aggregates of 6 to 10 mm; Batching: Mix the above-mentioned small-particle aggregate and large-particle aggregate in equal amounts to form waste auxiliary graphite crumbs, and mix the waste auxiliary graphite crumbs, electric calcined anthracite, high-quality graphite crumbs, calcined petroleum coke, and modified asphalt in a mass ratio of 20-30%, 5-10%, 30-35%, 10-15%, and 18-22%; Mixing: send the waste auxiliary graphite, electric calcined anthracite, high-quality graphite and calcined petroleum coke into a kneading pot with a heating temperature of 180±20℃ for heating and stirring. The stirring time is 45-60 minutes. When the temperature reaches 120-130℃, add the modified asphalt with a temperature of 175±5℃ and continue stirring for 40-70 minutes. When the temperature of the paste is 150-160℃, the materials are mixed and sent to the green billet forming process. Molding: The mixed materials are transported to the drying equipment for cooling, equalizing the temperature, and exhausting the fume. When the paste temperature reaches 125-135°C, it is discharged and sent into the mold barrel to be molded to obtain the electrode blank; Roasting: Roast the electrode blank in a ring roasting furnace at a temperature of 1200-1250°C for 840±10 hours, and then naturally cool to below 400±5°C before being taken out of the furnace to obtain a large-diameter carbon electrode.

[0006] A high-graphite carbon electrode prepared by the method, wherein the graphite content of the carbon electrode reaches more than 60%.

[0007] In the present invention, the same amount of waste auxiliary graphite fragments as high-quality graphite fragments is used, and the waste auxiliary graphite fragments are crushed and sieved, so that the requirements of high-quality and high-graphite carbon electrodes can be fully met. DETAILED DESCRIPTION

[0008] The present invention provides a method for preparing a high-graphite carbon electrode using waste auxiliary graphite, comprising the following steps: Crushing: First crush or grind the waste auxiliary graphite into powder; Screening: The crushed waste auxiliary graphite powder is screened into small particle aggregates of 2 to 6 mm and large particle aggregates of 6 to 10 mm; Batching: Mix the above-mentioned small-particle aggregate and large-particle aggregate in equal amounts. Then mix the waste auxiliary graphite, electric calcined anthracite, high-quality graphite, calcined petroleum coke, and modified asphalt in a mass ratio of 20-30%, 5-10%, 30-35%, 10-15%, and 18-22%; Mixing: send the waste auxiliary graphite, electric calcined anthracite, high-quality graphite and calcined petroleum coke batch materials into a kneading pot with a heating temperature of 180±20℃ for heating and stirring. The stirring time is 45-60 minutes. When the temperature reaches 120-130℃, add the modified asphalt with a temperature of 175±5℃ and continue stirring for 40-70 minutes. When the temperature of the paste material is 150-160℃, the materials are mixed and sent to the green billet molding process. Molding: The mixed materials are transported to the drying equipment for cooling, equalizing the temperature, and exhausting the fume. When the paste temperature reaches 125-135°C, it is discharged and sent into the mold barrel to be molded to obtain the electrode blank; Roasting: The electrode blank is roasted in a ring roasting furnace at a temperature of 1200°C for 840 hours, and then naturally cooled to below 400°C and taken out of the furnace to obtain a large-diameter electrode.

[0009] It is well known in the art that the application fields of carbon electrodes are different from those of graphite electrodes, and their electrical conductivity is also different. The electrical conductivity of carbon electrodes is inferior to that of graphitized electrodes, but the cost of graphitized electrodes is 3,000-5,000 yuan (RMB) higher than that of carbon electrodes. However, the electrical conductivity of carbon electrodes can be optimized by adding graphite, so people began to add high-quality graphite fragments to the raw materials. However, the use of waste auxiliary graphite fragments in the background technology has not been able to achieve a breakthrough, because the use strength of the electrode product cannot be guaranteed. In this solution, by adding waste auxiliary graphite fragments after crushing and screening, not only the high-quality graphite fragments are replaced and the graphite content is increased, but also the electrical conductivity of the electrode is equivalent to the level of adding the same amount of high-quality graphite fragments, and the use strength is guaranteed at the same time. The introduction of the waste auxiliary graphite fragments reduces the cost of high-quality graphite fragments by 1 / 2, and the comprehensive cost per ton of product is reduced by about 1,000-1,200 yuan after calculation.

[0010] The crushing and screening steps of this solution are to screen out the fine powder below 2 mm, which not only reduces the ash content in the electrode, but also improves the strength of the granular material. Therefore, this solution screens out the fine powder.

[0011] Furthermore, the particle size of the electro-calcined anthracite is 2-6 mm.

[0012] Furthermore, the particle size of the high-quality graphite is 10-16, 16-24 mm.

[0013] Furthermore, the particle size of the calcined petroleum coke is 0.06-0.08 mm. The calcined petroleum coke has a low resistivity due to the calcination process, and the conductive particles filled between the particles have a small particle size.

[0014] The invention discloses a high-graphite carbon electrode prepared by the method described above, wherein the graphite content of the carbon electrode reaches more than 60%.

[0015] Furthermore, the carbon electrode has a volume density of ≥1.62 g / cm³; a resistivity of ≤24.0 μ.Ωm; a flexural strength of ≥6.0 Mpa; and a thermal expansion coefficient of ≤4.0×10 -6 / ℃; thermal conductivity>30W / mk; elastic modulus≤10GPa.

[0016] Furthermore, the diameter is φ1150-1272mm.

[0017] Embodiment 1 A method for preparing a high-graphite carbon electrode using waste auxiliary graphite comprises the following steps: Crushing: First crush or grind the waste auxiliary graphite into powder; Screening: The crushed waste auxiliary graphite powder is screened into small particle aggregates of 2 to 6 mm and large particle aggregates of 6 to 10 mm; Batching: Mix the above-mentioned small-particle aggregate and large-particle aggregate in equal amounts to form waste auxiliary graphite crumbs, and mix the waste auxiliary graphite crumbs, electric calcined anthracite, high-quality graphite crumbs, calcined petroleum coke, and modified asphalt in a mass ratio of 20%, 10%, 30%, 15%, and 22%; Mixing: Send the waste auxiliary graphite, electric calcined anthracite, high-quality graphite and calcined petroleum coke into a kneading pot with a heating temperature of 180±20℃ for heating and stirring. The stirring time is 60 minutes. When the temperature reaches 130℃, add the modified asphalt with a temperature of 175℃ and continue stirring for 40 minutes. When the temperature of the paste reaches 160℃, the materials are mixed and sent to the green billet molding process. Molding: The mixed materials are transported to the drying equipment for cooling, equalizing the temperature, and exhausting the fume. When the paste temperature reaches 125°C, it is discharged and sent into the mold barrel to be molded to obtain the electrode blank; Roasting: The electrode blank is roasted in a ring roasting furnace at a temperature of 1200°C for 840 hours, and then naturally cooled to below 400°C and taken out of the furnace to obtain a large-diameter carbon electrode.

[0018] Embodiment 2 In the batching step: the above-mentioned small-particle aggregate and large-particle aggregate are mixed in equal amounts to form waste auxiliary graphite fragments, and the waste auxiliary graphite fragments, electric calcined anthracite, high-quality graphite fragments, calcined petroleum coke, and modified asphalt are configured in a mass ratio of 25%, 8%, 30%, 10%, and 20%. Other steps and processes are the same as those in Example 1.

[0019] Embodiment 3 In the batching step: the above-mentioned small-particle aggregate and large-particle aggregate are mixed in equal amounts to form waste auxiliary graphite fragments, and the waste auxiliary graphite fragments, electric calcined anthracite, high-quality graphite fragments, calcined petroleum coke, and modified asphalt are configured in a mass ratio of 30%, 10%, 32%, 10%, and 18%. Other steps and processes are the same as those in Example 1.

[0020] The physical and chemical properties of the carbon electrodes produced in the above three embodiments were tested, as shown in Table 1.

[0021] As shown in the table above, after the waste auxiliary graphite fragments of the present invention are used, the physical and chemical properties are not lost and still meet the quality of high-quality carbon electrodes.

[0022] Comparative Example 1 In the batching step, the crushed waste auxiliary graphite (actually the crushed powder of the waste auxiliary graphite with a particle size of less than 2 mm without screening), electric calcined anthracite, high-quality graphite, calcined petroleum coke, and modified asphalt are prepared in the same proportion as in Example 1, and then mixed. The other steps and processes are the same as in Example 1.

[0023] Comparative Example 2 In the batching step: crushed waste auxiliary graphite (actually, crushed powder of waste auxiliary graphite with a particle size of less than 2 mm without screening), electric calcined anthracite, high-quality graphite, calcined petroleum coke, and modified asphalt are prepared in the same proportion as in Example 2, and then mixed. Other steps and processes are the same as in Example 2.

[0024] Comparative Example 3 In the batching step, the crushed waste auxiliary graphite (actually the crushed powder of the waste auxiliary graphite with a particle size of less than 2 mm without screening), electric calcined anthracite, high-quality graphite, calcined petroleum coke, and modified asphalt are prepared in the same proportion as in Example 3, and then mixed. The other steps and processes are the same as in Example 3.

[0025] The physical and chemical properties of the carbon electrodes produced in the above three comparative examples were tested, as shown in Table 2.

[0026] In the three comparative examples, the waste auxiliary graphite fragments with very fine particle size were not processed, and were put into the batching and mixing together with other raw materials. The test data showed that the resistivity increased and the density decreased due to the presence of the extremely fine graphite fragments. At the same time, due to their presence, the strength of the electrode decreased significantly. Obviously, the extremely fine graphite fragments, especially those with a particle size of less than 2 mm, can seriously affect the quality of the electrode.

[0027] Comparative Example 4 Instead of using the waste auxiliary graphite crushed and screened in Example 1, the waste auxiliary graphite crushed in the ingredients are replaced with high-quality graphite crushed with the same mass, that is, the electro-calcined anthracite, high-quality graphite crushed, calcined petroleum coke, and modified asphalt are configured according to a mass ratio of 10%, 50%, 15%, and 22%. The other steps and processes are the same as in Example 1. The physical and chemical properties of the carbon electrode produced in this comparative example 4 are tested, as shown in Table 3.

[0028] In the comparative example 4, all the graphite pieces are high-quality graphite pieces, and no waste auxiliary graphite pieces are used, and the electrode quality is excellent. However, since all the high-quality graphite pieces are used, the cost is twice that of the embodiment 1. It can also be seen from the comparative example that the physical and chemical properties of the embodiments 1, 2, and 3 are almost equivalent to those of the comparative example 4. Therefore, in the present invention, the waste auxiliary graphite pieces are used in an amount equal to that of the high-quality graphite pieces, and are crushed and sieved, so that the high quality requirements can be fully achieved.

[0029] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of this patent.

Claims

1. A method for preparing a high-graphite carbon electrode using waste auxiliary graphite, characterized in that The following steps are involved: Crushing: Firstly, crush the waste auxiliary graphite into powder; Screening: The crushed waste auxiliary graphite powder is screened into small particle aggregates of 2 to 6 mm and large particle aggregates of 6 to 10 mm; Batching: Mix the above-mentioned small-particle aggregate and large-particle aggregate in equal amounts to form waste auxiliary graphite crumbs, and mix the waste auxiliary graphite crumbs, electric calcined anthracite, high-quality graphite crumbs, calcined petroleum coke, and modified asphalt in a mass ratio of 20-30%, 5-10%, 30-35%, 10-15%, and 18-22%; Mixing: send the waste auxiliary graphite, electric calcined anthracite, high-quality graphite and calcined petroleum coke into a kneading pot with a heating temperature of 180±20℃ for heating and stirring. The stirring time is 45-60 minutes. When the temperature reaches 120-130℃, add the modified asphalt with a temperature of 175±5℃ and continue stirring for 40-70 minutes. When the temperature of the paste is 150-160℃, the materials are mixed and sent to the green billet forming process. Molding: The mixed materials are transported to the drying equipment for cooling, equalizing the temperature, and exhausting the fume. When the paste temperature reaches 125-135°C, it is discharged and sent into the mold barrel to be molded to obtain the electrode blank; Roasting: Roast the electrode blank in a ring roasting furnace at a temperature of 1200-1250°C for 840±10 hours, and then naturally cool to below 400±5°C before being taken out of the furnace to obtain a large-diameter carbon electrode.

2. The method for preparing a high-graphite carbon electrode using waste auxiliary graphite according to claim 1, characterized in that: The particle size of the electro-calcined anthracite is 2-6 mm.

3. The method for preparing a high-graphite carbon electrode using waste auxiliary graphite according to claim 1, characterized in that: The particle size of the high-quality graphite is 10-16 mm.

4. The method for preparing a high-graphite carbon electrode using waste auxiliary graphite according to claim 1, characterized in that: The particle size of the calcined petroleum coke is 0.06-0.08 mm.

5. A high-graphite carbon electrode prepared by the method according to any one of claims 1 to 4, characterized in that: The graphite content of the carbon electrode reaches more than 60%.

6. The high graphite carbon electrode according to claim 5, characterized in that: The carbon electrode has a volume density of ≥1.62 g / cm³; a resistivity of ≤24.0 μ.Ωm; a flexural strength of ≥6.0 Mpa; and a thermal expansion coefficient of ≤4.0×10 -6 / ℃; thermal conductivity>30 W / mk; elastic modulus≤10 GPa.

7. The high graphite carbon electrode according to claim 6, characterized in that: The diameter is φ1150-1272mm.

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