Coal pitch modification isostatic pressing production process
Through the coal asphalt modified isostatic pressure production process, combined with the characteristics of coal-based needle coke, high-temperature modified asphalt and sulfur, the problems of low yield and roasted cracking in isostatic graphite production are solved, and the production of high-quality isostatic graphite is achieved.
Patent Information
- Application Number
- CN202411953214.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-03-28
AI Technical Summary
In the existing isostatic graphite production technology, the yield rate is low and the problem of roasting and cracking is serious, making it difficult to effectively improve the yield and quality of high-end isostatic graphite.
The coal asphalt modified isostatic pressure production process is adopted, and high-quality isostatic graphite is prepared by mixing coal-based needle coke with high-temperature modified asphalt and sulfur in a specific proportion, and controlling the temperature and time in different process steps.
The yield rate of isostatic graphite is improved, the risk of roasting and cracking is reduced, and the improvement of product quality is ensured by precise control of process parameters.
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of graphite production, and in particular relates to a coal tar pitch modified isostatic pressing production process. Background Art
[0002] Isostatic graphite is a new type of graphite material made by pressing high-purity graphite, which has a series of excellent properties. Compared with ordinary graphite, the structure of isostatic graphite is finer and denser, with good uniformity, low thermal expansion coefficient, excellent thermal shock resistance, isotropy, strong chemical corrosion resistance, good thermal and electrical conductivity, and excellent mechanical processing performance. It is precisely because of this series of excellent properties that isostatic graphite has attracted extensive attention in the fields of metallurgy, chemistry, electricity, aerospace and atomic energy industry.
[0003] However, the existing isostatic graphite production technology is relatively weak, the output and quality of high-end isostatic graphite have not been effectively improved, the one-time molding yield is low, and the problem of roasting cracking is relatively serious. Summary of the invention
[0004] In order to overcome the shortcomings of the prior art and solve the technical problems of low one-time forming yield and calcination cracking in the prior isostatic graphite production technology, the present invention provides a coal tar pitch modified isostatic pressing production process.
[0005] The present invention is achieved through the following technical solutions.
[0006] The invention provides an isostatic graphite, which comprises 64% of coal-based needle coke, 32.4%-34.2% of high-temperature modified asphalt and 1.8%-3.6% of sulfur by mass fraction.
[0007] Furthermore, the sulfur content of the coal-based needle coke is ≤0.3%, the ash content of the coal-based needle coke is ≤0.25%, the volatile matter of the coal-based needle coke is ≤0.8%, the moisture content of the coal-based needle coke is ≤0.5%, and the true density of the coal-based needle coke is 1.98 g / cm 3 The powder resistivity of the coal-based needle coke is 550-600 μΩ.m.
[0008] Furthermore, the softening point of the high-temperature modified asphalt is 118-130°C, the volatile matter of the high-temperature modified asphalt is 47%-57%, the ash content of the high-temperature modified asphalt is ≤0.3%, the moisture content of the high-temperature modified asphalt is ≤1%, the toluene insoluble matter content of the high-temperature modified asphalt is 25%-37%, the quinoline insoluble matter content of the high-temperature modified asphalt is 6%-12%, and the coking value of the high-temperature modified asphalt is ≥60%.
[0009] Furthermore, the purity of the sulfur is ≥99.9%, and the ash content of the sulfur is ≤0.03%.
[0010] Furthermore, a coal tar pitch modified isostatic pressing production process for preparing an isostatically pressed graphite comprises the following steps:
[0011] 1) Crushing and primary grinding of coal-based needle coke:
[0012] The coal-based needle coke is crushed by a crusher and ground into powder once to a particle size of 10 μm;
[0013] 2) Preparation of mixed binder:
[0014] 32.4%-34.2% of high temperature modified asphalt is melted at 120-130°C, 1.8%-3.6% of sulfur is added and stirred evenly to obtain a mixed binder;
[0015] 3) Dry mixing:
[0016] 64% of coal-based needle coke is dry mixed in a kneading pot;
[0017] 4) Wet mixing:
[0018] The dry-mixed material and the mixed binder prepared in step 2) are wet-mixed in a kneading pot, and the wet-mixed material is cooled in the kneading pot;
[0019] 5) Secondary grinding:
[0020] The cooled material is ground twice on a Raymond mill to a particle size of 35-40 μm;
[0021] 6) Isostatic pressing:
[0022] The secondary ground material is put into a rubber sleeve, and after vibration and vacuum operation, it is placed in an isostatic press for molding at a molding pressure of 123-165Mpa;
[0023] 7) Calcination:
[0024] The isostatically pressed material is placed in a well chamber roasting furnace for roasting, the maximum roasting temperature is 950°C, and the roasting time is 910h;
[0025] 8) Graphitization treatment:
[0026] The calcined material is placed in a medium frequency graphitization furnace for graphitization treatment. The maximum graphitization temperature is above 2800°C and the graphitization treatment time is 14 days.
[0027] Furthermore, the dry mixing temperature in step 3) is 120-130°C.
[0028] Furthermore, the wet mixing temperature in step 4) is 130-140° C., and the wet mixing time is 60-90 min.
[0029] Furthermore, the wet mixing temperature in step 4) is 140-150° C., and the wet mixing time is less than or equal to 30 minutes.
[0030] The beneficial effects achieved by the present invention are as follows: the present invention uses a mixed binder, sulfur in the mixed binder, the temperature at which sulfur and high-temperature modified asphalt begin to react chemically is 130°C, and as the temperature rises, the reaction speed gradually accelerates, the reaction is relatively mild at 130-150°C, and the reaction is violent after 150°C, and the sulfur can play a role in increasing the plasticity of the material without reacting chemically with the high-temperature modified asphalt, but after the sulfur reacts chemically with the high-temperature modified asphalt, the viscosity of the high-temperature modified asphalt is increased, and the plasticity of the material becomes worse; the temperature of the wet mixing of the present invention is controlled as much as possible to be 130-1 40℃, reducing the chemical reaction between sulfur and high-temperature modified asphalt, playing a role in increasing plasticity, and in the roasting stage, sulfur and high-temperature modified asphalt react chemically, thereby increasing the coking value of high-temperature modified asphalt and reducing the risk of roasting cracking; coal-based needle coke is selected, and the raw material is easy to obtain and the price is cheap; a medium-frequency graphitization furnace is selected for graphitization operation, and the graphitization temperature can be controlled as needed; the present invention also proposes a coal tar modified isostatic pressing production process, which does not overlap with the traditional carbon product process, and the process parameters of each process are controlled separately, which can ensure the precise control of the process parameters and ensure product quality.
[0031] Compared with the prior art, the present invention has the advantages of reducing the risk of cracking during roasting and increasing the yield. DETAILED DESCRIPTION
[0032] The present invention is further described in detail below in conjunction with embodiments.
[0033] Example 1
[0034] An isostatic graphite comprises, by mass fraction, 64% of coal-based needle coke, 34.2% of high-temperature modified asphalt and 1.8% of sulfur, wherein the sulfur content of the coal-based needle coke is ≤0.3%, the ash content of the coal-based needle coke is ≤0.25%, the volatile matter of the coal-based needle coke is ≤0.8%, the moisture content of the coal-based needle coke is ≤0.5%, and the true density of the coal-based needle coke is 1.98 g / cm 3The powder resistivity of the coal-based needle coke is 550-600 μΩ.m. The raw materials of the coal-based needle coke are easily available and cheap. The softening point of the high-temperature modified asphalt is 118-130°C, the volatile matter of the high-temperature modified asphalt is 47%-57%, the ash content of the high-temperature modified asphalt is ≤0.3%, the moisture content of the high-temperature modified asphalt is ≤1%, the toluene insoluble content of the high-temperature modified asphalt is 25%-37%, the quinoline insoluble content of the high-temperature modified asphalt is 6%-12%, and the coking value of the high-temperature modified asphalt is ≥60%; the purity of the sulfur is ≥99.9%, and the ash content of the sulfur is ≤0.03%.
[0035] A coal tar pitch modified isostatic pressing production process for preparing isostatically pressed graphite comprises the following steps:
[0036] 1) Crushing and primary grinding of coal-based needle coke:
[0037] The coal-based needle coke is crushed by a crusher and ground into powder once to a particle size of 10 μm;
[0038] 2) Preparation of mixed binder:
[0039] 34.2% high temperature modified asphalt was melted at 120°C, 1.8% sulfur was added and stirred evenly to obtain a mixed binder. The mixed binder was relatively viscous at the beginning of stirring, and the viscosity of the mixed binder decreased as sulfur was gradually added.
[0040] The temperature at which sulfur and high-temperature modified asphalt begin to react chemically is 130°C. As the temperature rises, the reaction speed gradually accelerates. The reaction is relatively mild at 130-150°C, and the reaction is violent above 150°C. Without chemically reacting with high-temperature modified asphalt, sulfur can increase the plasticity of the material. However, after sulfur and high-temperature modified asphalt react chemically, the viscosity of the high-temperature modified asphalt increases, and the plasticity of the material deteriorates.
[0041] 3) Dry mixing:
[0042] 64% of coal-based needle coke is dry mixed in a kneading pot at a dry mixing temperature of 120°C;
[0043] 4) Wet mixing:
[0044] The dry-mixed material and the mixed binder prepared in step 2) are wet-mixed in a kneading pot, the wet-mixing temperature is 130° C., and the wet-mixing time is 60 min. If the plasticity of the wet-mixed material is not good, the wet-mixing temperature is increased to 140° C., but the wet-mixing time cannot exceed 30 min, and the wet-mixing temperature cannot exceed 150° C., so as to avoid chemical reaction between sulfur and high-temperature modified asphalt, thereby increasing plasticity. The wet-mixed material is cooled in the kneading pot;
[0045] 5) Secondary grinding:
[0046] The cooled material is ground twice on a Raymond mill to a particle size of 35-40 μm;
[0047] 6) Isostatic pressing:
[0048] The secondary ground material is put into a rubber sleeve, and after vibration and vacuum operation, it is placed in an isostatic press for molding at a molding pressure of 123Mpa;
[0049] 7) Calcination:
[0050] The isostatically pressed materials are loaded into a well chamber roasting furnace for roasting. The maximum roasting temperature is 950°C and the roasting time is 910 hours. During this process, sulfur reacts chemically with the high-temperature modified asphalt, thereby increasing the coking value of the high-temperature modified asphalt and reducing the risk of roasting cracking.
[0051] 8) Graphitization treatment:
[0052] The calcined material is loaded into a medium frequency graphitization furnace for graphitization treatment. The maximum graphitization temperature is above 2800°C and the graphitization treatment time is 14 days. The medium frequency graphitization furnace is used for graphitization operation, and the graphitization temperature can be controlled as needed.
[0053] The performance of the isostatic graphite in this embodiment was tested. The product structure after the roasting operation was good, and the bulk density was 1.65g / m 2 The volume density of the product after graphitization is 1.86g / m 2 The compressive strength of the product after graphitization treatment is 70MPa.
[0054] The coal tar modified isostatic pressing production process in this embodiment does not overlap with the traditional carbon product process. The process parameters of each process are controlled separately, which can ensure the precise control of the process parameters and ensure product quality.
[0055] Example 2
[0056] An isostatic graphite comprises 64% coal-based needle coke, 33.3% high-temperature modified asphalt and 2.7% sulfur by mass fraction. The sulfur content of the coal-based needle coke is ≤0.3%, the ash content of the coal-based needle coke is ≤0.25%, the volatile matter of the coal-based needle coke is ≤0.8%, the moisture content of the coal-based needle coke is ≤0.5%, and the true density of the coal-based needle coke is 1.98 g / cm 3The powder resistivity of the coal-based needle coke is 550-600 μΩ.m. The raw materials of the coal-based needle coke are easily available and cheap. The softening point of the high-temperature modified asphalt is 118-130°C, the volatile matter of the high-temperature modified asphalt is 47%-57%, the ash content of the high-temperature modified asphalt is ≤0.3%, the moisture content of the high-temperature modified asphalt is ≤1%, the toluene insoluble content of the high-temperature modified asphalt is 25%-37%, the quinoline insoluble content of the high-temperature modified asphalt is 6%-12%, and the coking value of the high-temperature modified asphalt is ≥60%; the purity of the sulfur is ≥99.9%, and the ash content of the sulfur is ≤0.03%.
[0057] A coal tar pitch modified isostatic pressing production process for preparing isostatically pressed graphite comprises the following steps:
[0058] 1) Crushing and primary grinding of coal-based needle coke:
[0059] The coal-based needle coke is crushed by a crusher and ground into powder once to a particle size of 10 μm;
[0060] 2) Preparation of mixed binder:
[0061] 33.3% high temperature modified asphalt is melted at 125°C, 2.7% sulfur is added and stirred evenly to obtain a mixed binder; the mixed binder is relatively viscous at the beginning of stirring, and the viscosity of the mixed binder decreases as sulfur is gradually added;
[0062] The temperature at which sulfur and high-temperature modified asphalt begin to react chemically is 130°C. As the temperature rises, the reaction speed gradually accelerates. The reaction is relatively mild at 130-150°C, and the reaction is violent above 150°C. Without chemically reacting with high-temperature modified asphalt, sulfur can increase the plasticity of the material. However, after sulfur and high-temperature modified asphalt react chemically, the viscosity of the high-temperature modified asphalt increases, and the plasticity of the material deteriorates.
[0063] 3) Dry mixing:
[0064] 64% of coal-based needle coke is dry mixed in a kneading pot at a dry mixing temperature of 125°C;
[0065] 4) Wet mixing:
[0066] The dry-mixed material and the mixed binder prepared in step 2) are wet-mixed in a kneading pot, the wet-mixing temperature is 130° C., and the wet-mixing time is 60 min. If the plasticity of the wet-mixed material is not good, the wet-mixing temperature is increased to 140° C., but the wet-mixing time cannot exceed 30 min, and the wet-mixing temperature cannot exceed 150° C., so as to avoid chemical reaction between sulfur and high-temperature modified asphalt, thereby increasing plasticity. The wet-mixed material is cooled in the kneading pot;
[0067] 5) Secondary grinding:
[0068] The cooled material is ground twice on a Raymond mill to a particle size of 35-40 μm;
[0069] 6) Isostatic pressing:
[0070] The secondary ground material is put into a rubber sleeve, and after vibration and vacuum operation, it is placed in an isostatic press for molding at a molding pressure of 140Mpa.
[0071] 7) Calcination:
[0072] The isostatically pressed materials are loaded into a well chamber roasting furnace for roasting. The maximum roasting temperature is 950°C and the roasting time is 910 hours. During this process, sulfur reacts chemically with the high-temperature modified asphalt, thereby increasing the coking value of the high-temperature modified asphalt and reducing the risk of roasting cracking.
[0073] 8) Graphitization treatment:
[0074] The calcined material is loaded into a medium frequency graphitization furnace for graphitization treatment. The maximum graphitization temperature is above 2800°C and the graphitization treatment time is 14 days. The medium frequency graphitization furnace is used for graphitization operation, and the graphitization temperature can be controlled as needed.
[0075] The performance of the isostatic graphite in this embodiment was tested. The product structure after the calcination operation was good, and the bulk density was 1.68g / m 2 The volume density of the product after graphitization is 1.88g / m 2 The compressive strength of the product after graphitization treatment is 73MPa.
[0076] The coal tar modified isostatic pressing production process in this embodiment does not overlap with the traditional carbon product process. The process parameters of each process are controlled separately, which can ensure the precise control of the process parameters and ensure product quality.
[0077] Example 3
[0078] An isostatic graphite comprises, by mass fraction, 64% of coal-based needle coke, 32.4% of high-temperature modified asphalt and 3.6% of sulfur, wherein the sulfur content of the coal-based needle coke is ≤0.3%, the ash content of the coal-based needle coke is ≤0.25%, the volatile matter of the coal-based needle coke is ≤0.8%, the moisture content of the coal-based needle coke is ≤0.5%, and the true density of the coal-based needle coke is 1.98 g / cm 3The powder resistivity of the coal-based needle coke is 550-600 μΩ.m. The raw materials of the coal-based needle coke are easily available and cheap. The softening point of the high-temperature modified asphalt is 118-130°C, the volatile matter of the high-temperature modified asphalt is 47%-57%, the ash content of the high-temperature modified asphalt is ≤0.3%, the moisture content of the high-temperature modified asphalt is ≤1%, the toluene insoluble content of the high-temperature modified asphalt is 25%-37%, the quinoline insoluble content of the high-temperature modified asphalt is 6%-12%, and the coking value of the high-temperature modified asphalt is ≥60%; the purity of the sulfur is ≥99.9%, and the ash content of the sulfur is ≤0.03%.
[0079] A coal tar pitch modified isostatic pressing production process for preparing isostatically pressed graphite comprises the following steps:
[0080] 1) Crushing and primary grinding of coal-based needle coke:
[0081] The coal-based needle coke is crushed by a crusher and ground into powder once to a particle size of 10 μm;
[0082] 2) Preparation of mixed binder:
[0083] 32.4% high temperature modified asphalt is melted at 130°C, 3.6% sulfur is added and stirred evenly to obtain a mixed binder; the mixed binder is relatively viscous at the beginning of stirring, and the viscosity of the mixed binder decreases as sulfur is gradually added;
[0084] The temperature at which sulfur and high-temperature modified asphalt begin to react chemically is 130°C. As the temperature rises, the reaction speed gradually accelerates. The reaction is relatively mild at 130-150°C, and the reaction is violent above 150°C. Without chemically reacting with high-temperature modified asphalt, sulfur can increase the plasticity of the material. However, after sulfur and high-temperature modified asphalt react chemically, the viscosity of the high-temperature modified asphalt increases, and the plasticity of the material deteriorates.
[0085] 3) Dry mixing:
[0086] 64% of coal-based needle coke is dry mixed in a kneading pot at a dry mixing temperature of 130°C;
[0087] 4) Wet mixing:
[0088] The dry-mixed material and the mixed binder prepared in step 2) are wet-mixed in a kneading pot, the wet-mixing temperature is 125° C., and the wet-mixing time is 60 min. If the plasticity of the wet-mixed material is not good, the wet-mixing temperature is increased to 145° C., but the wet-mixing time cannot exceed 30 min, and the wet-mixing temperature cannot exceed 150° C., so as to avoid chemical reaction between sulfur and high-temperature modified asphalt, thereby increasing plasticity. The wet-mixed material is cooled in the kneading pot;
[0089] 5) Secondary grinding:
[0090] The cooled material is ground twice on a Raymond mill to a particle size of 35-40 μm;
[0091] 6) Isostatic pressing:
[0092] The secondary ground material is put into a rubber sleeve, and after vibration and vacuum operation, it is placed in an isostatic press for molding at a molding pressure of 165Mpa;
[0093] 7) Calcination:
[0094] The isostatically pressed materials are loaded into a well chamber roasting furnace for roasting. The maximum roasting temperature is 950°C and the roasting time is 910 hours. During this process, sulfur reacts chemically with the high-temperature modified asphalt, thereby increasing the coking value of the high-temperature modified asphalt and reducing the risk of roasting cracking.
[0095] 8) Graphitization treatment:
[0096] The calcined material is loaded into a medium frequency graphitization furnace for graphitization treatment. The maximum graphitization temperature is above 2800°C and the graphitization treatment time is 14 days. The medium frequency graphitization furnace is used for graphitization operation, and the graphitization temperature can be controlled as needed.
[0097] The performance of the isostatic graphite in this embodiment was tested. The product structure after the roasting operation was good, and the bulk density was 1.70g / m 2 The volume density of the product after graphitization is 1.91g / m 2 The compressive strength of the product after graphitization treatment is 77MPa.
[0098] The coal tar modified isostatic pressing production process in this embodiment does not overlap with the traditional carbon product process. The process parameters of each process are controlled separately, which can ensure the precise control of the process parameters and ensure product quality.
[0099] The above describes in detail the implementation modes of the present invention, but the present invention is not limited to the above implementation modes. The implementation modes can still be changed within the knowledge scope of ordinary technicians in the field. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. An isostatically pressed graphite, characterized in that: The mass fraction includes 64% coal-based needle coke, 32.4%-34.2% high-temperature modified asphalt and 1.8%-3.6% sulfur.
2. The isostatically pressed graphite according to claim 1, characterized in that: The sulfur content of the coal-based needle coke is ≤0.3%, the ash content of the coal-based needle coke is ≤0.25%, the volatile matter of the coal-based needle coke is ≤0.8%, the moisture content of the coal-based needle coke is ≤0.5%, and the true density of the coal-based needle coke is 1.98 g / cm 3 The powder resistivity of the coal-based needle coke is 550-600 μΩ.m.
3. The isostatically pressed graphite according to claim 1, characterized in that: The softening point of the high-temperature modified asphalt is 118-130°C, the volatile matter of the high-temperature modified asphalt is 47%-57%, the ash content of the high-temperature modified asphalt is ≤0.3%, the moisture content of the high-temperature modified asphalt is ≤1%, the toluene insoluble matter content of the high-temperature modified asphalt is 25%-37%, the quinoline insoluble matter content of the high-temperature modified asphalt is 6%-12%, and the coking value of the high-temperature modified asphalt is ≥60%.
4. The isostatically pressed graphite according to claim 1, characterized in that: The purity of the sulfur is ≥99.9%, and the ash content of the sulfur is ≤0.03%.
5. A coal tar pitch modified isostatic pressing production process, characterized in that: The method for preparing an isostatic graphite as claimed in any one of claims 1 to 4 comprises the following steps: 1) Crushing and primary grinding of coal-based needle coke: The coal-based needle coke is crushed by a crusher and ground into powder once to a particle size of 10 μm; 2) Preparation of mixed binder: 32.4%-34.2% of high temperature modified asphalt is melted at 120-130°C, 1.8%-3.6% of sulfur is added and stirred evenly to obtain a mixed binder; 3) Dry mixing: 64% of coal-based needle coke is dry mixed in a kneading pot; 4) Wet mixing: The dry-mixed material and the mixed binder prepared in step 2) are wet-mixed in a kneading pot, and the wet-mixed material is cooled in the kneading pot; 5) Secondary grinding: The cooled material is ground twice on a Raymond mill to a particle size of 35-40 μm; 6) Isostatic pressing: The secondary ground material is put into a rubber sleeve, and after vibration and vacuum operation, it is placed in an isostatic press for molding at a molding pressure of 123-165Mpa; 7) Calcination: The isostatically pressed material is placed in a well chamber roasting furnace for roasting, the maximum roasting temperature is 950°C, and the roasting time is 910h; 8) Graphitization treatment: The calcined material is placed in a medium frequency graphitization furnace for graphitization treatment. The maximum graphitization temperature is above 2800°C and the graphitization treatment time is 14 days.
6. The isostatic pressing production process for modified coal tar pitch according to claim 5, characterized in that: The dry mixing temperature in step 3) is 120-130°C.
7. The isostatic pressing production process for modified coal tar pitch according to claim 5, characterized in that: The wet mixing temperature in step 4) is 130-140° C., and the wet mixing time is 60-90 min.
8. The isostatic pressing production process for modified coal tar pitch according to claim 5, characterized in that: The wet mixing temperature in step 4) is 140-150° C., and the wet mixing time is less than or equal to 30 minutes.