CN112457014A - Ultrahigh-power graphite electrode joint and preparation process thereof - Google Patents
Ultrahigh-power graphite electrode joint and preparation process thereof Download PDFInfo
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- CN112457014A CN112457014A CN202011133785.1A CN202011133785A CN112457014A CN 112457014 A CN112457014 A CN 112457014A CN 202011133785 A CN202011133785 A CN 202011133785A CN 112457014 A CN112457014 A CN 112457014A
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 48
- 239000010439 graphite Substances 0.000 title claims abstract description 40
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 40
- 238000002360 preparation method Methods 0.000 title abstract description 7
- 239000010426 asphalt Substances 0.000 claims abstract description 34
- 239000011331 needle coke Substances 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 22
- JOXIMZWYDAKGHI-UHFFFAOYSA-N toluene-4-sulfonic acid Chemical compound CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000011230 binding agent Substances 0.000 claims abstract description 14
- 238000005470 impregnation Methods 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims abstract description 11
- 238000004519 manufacturing process Methods 0.000 claims abstract description 9
- 239000011329 calcined coke Substances 0.000 claims abstract description 8
- 238000004898 kneading Methods 0.000 claims abstract description 8
- 238000001125 extrusion Methods 0.000 claims abstract description 7
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims abstract description 7
- BTFQKIATRPGRBS-UHFFFAOYSA-N o-tolualdehyde Chemical compound CC1=CC=CC=C1C=O BTFQKIATRPGRBS-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000000654 additive Substances 0.000 claims abstract description 6
- 230000000996 additive effect Effects 0.000 claims abstract description 5
- 239000002994 raw material Substances 0.000 claims abstract description 5
- 238000003754 machining Methods 0.000 claims abstract description 4
- 230000005540 biological transmission Effects 0.000 claims description 15
- 238000001816 cooling Methods 0.000 claims description 9
- 238000007599 discharging Methods 0.000 claims description 9
- 238000005087 graphitization Methods 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 9
- 238000004140 cleaning Methods 0.000 claims description 6
- 239000000498 cooling water Substances 0.000 claims description 6
- 238000007580 dry-mixing Methods 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000002955 isolation Methods 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 239000000126 substance Substances 0.000 abstract description 2
- 238000007598 dipping method Methods 0.000 abstract 1
- 230000007547 defect Effects 0.000 description 2
- 238000010891 electric arc Methods 0.000 description 2
- FXLOVSHXALFLKQ-UHFFFAOYSA-N p-tolualdehyde Chemical compound CC1=CC=C(C=O)C=C1 FXLOVSHXALFLKQ-UHFFFAOYSA-N 0.000 description 2
- 241001391944 Commicarpus scandens Species 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
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- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
- C04B35/522—Graphite
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
- C04B35/528—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite obtained from carbonaceous particles with or without other non-organic components
- C04B35/532—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite obtained from carbonaceous particles with or without other non-organic components containing a carbonisable binder
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/64—Burning or sintering processes
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B7/00—Heating by electric discharge
- H05B7/02—Details
- H05B7/10—Mountings, supports, terminals or arrangements for feeding or guiding electrodes
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- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/327—Iron group oxides, their mixed metal oxides, or oxide-forming salts thereof
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Abstract
An ultrahigh-power graphite electrode joint and a preparation process thereof belong to the technical field of graphite electrode joints and solve the technical problems of low breaking strength, insufficient physicochemical indexes, low high-grade product rate and the like of the conventional ultrahigh-power graphite electrode joint. The technical scheme of the invention is as follows: an ultra-high power graphite electrode joint is prepared from the following raw materials: 45 parts by weight of needle coke, 55 parts by weight of calcined coke powder, 25 parts by weight of asphalt binder and 0.5 part by weight of Fe2O3An additive; methylbenzaldehyde and p-toluenesulfonic acid are added to the asphalt binder. The process comprises the following steps: 1, preparing materials; 2 kneading and making paste; 3, extrusion forming; 4, primary roasting; 5, primary dipping; 6, secondary roasting; 7, secondary impregnation; 8, roasting for three times; 9, graphitizing; 10 machining. The invention makes the bulk density resistantThe folding strength is improved, various physical and chemical indexes are better than those of the original product, and the production cost is greatly reduced.
Description
Technical Field
The invention belongs to the technical field of graphite electrode connectors, and particularly relates to an ultrahigh-power graphite electrode connector and a preparation process thereof.
Background
When the ultrahigh power graphite electrode is used in an electric arc furnace, the consumption caused by electrode breakage accounts for more than 10% of the total consumption every year, which is mainly caused by the fact that the rupture strength of an ultrahigh power graphite electrode joint is not large and the physicochemical indexes are not excellent enough. In practical production processes, the quality of graphite electrode joints is directly related to the use of the electrode joints in electric arc furnaces.
Because the indexes of the graphite electrode joint such as breaking strength, volume density, resistance and the like are higher in requirement, the graphite electrode joint can be graphitized after being fully coked and dipped for three times and baked for four times in the prior production, but even in the prior production, the high-grade product rate of the graphite electrode joint is still not high, and part of the graphite electrode joint can only be used on a low-grade graphite electrode, so that the production cost of an enterprise is high.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides an ultrahigh-power graphite electrode joint and a preparation process thereof, and solves the technical problems of low breaking strength, insufficient physicochemical indexes, low high-grade product rate and the like of the conventional ultrahigh-power graphite electrode joint.
In order to solve the problems, the technical scheme of the invention is as follows: an ultra high power graphite electrode joint, wherein: is prepared from the following raw materials: 45 parts of needle coke, 55 parts of calcined coke powder, 25 parts of asphalt binder and 0.5 part of Fe2O3An additive;
the needle coke comprises 17 parts by weight of needle coke with the particle size of 1-2mm, 15 parts by weight of needle coke with the particle size of 0.5-1mm and 13 parts by weight of needle coke with the particle size of 0-0.5 mm; the asphalt binder is added with methyl benzaldehyde and p-toluenesulfonic acid, wherein the weight of the added methyl benzaldehyde accounts for 2-3% of the weight of the asphalt binder, and the weight of the added p-toluenesulfonic acid accounts for 2-3% of the weight of the asphalt binder.
Furthermore, the ultrahigh power graphite electrode joint refers to a graphite electrode joint with the diameter of less than or equal to 289 mm.
A preparation process of an ultrahigh-power graphite electrode joint comprises the following steps: the method comprises the following process steps:
1) preparing materials: selecting 17 parts by weight of needle coke with the grain diameter of 1-2mm, 15 parts by weight of needle coke with the grain diameter of 0.5-1mm, 13 parts by weight of needle coke with the grain diameter of 0-0.5mm, 55 parts by weight of calcined coke powder and 0.5 part by weight of Fe2O3As an aggregate;
2) kneading and making paste: heating the aggregate to 110 ℃, then unloading the aggregate into a kneading pot, performing dry mixing for 10-15 minutes until the temperature reaches 140-;
3) extrusion molding: feeding the cooled paste obtained in the step 2) into a 2500T press, vacuumizing and tamping a material chamber of the press at the temperature of 135-140 ℃, keeping the vacuum degree above 0.8Mbar for not less than 3 minutes, tamping at the tamping pressure of 220KG, keeping the pressure at the pressure of 240KG for not less than 5 minutes, extruding the material at the extrusion speed of 15mm/s after the tamping drum is finished to prepare a pressed product, wherein the volume density is not less than 1.80g/cm3；
4) Primary roasting: the pressed product is put into a ring type roasting furnace with a cover for primary roasting, and the temperature rise curve uses a 420-hour curve: firstly, raising the temperature from room temperature to 130 ℃, raising the temperature by 4.4 ℃ per hour at the temperature of 130-; the temperature is raised to 1.4 ℃ per hour at 351-400 ℃, the temperature is raised to 35 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 0.8 ℃ per hour at 4.1-500 ℃, the temperature is raised to 120 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised by 1.4 ℃ per hour at the temperature of 501-600 ℃, the temperature is raised by 70 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised by 2.5 ℃ per hour at the temperature of 601-700 ℃, the temperature is raised for 40 hours, and the fluctuation range is +/-10 ℃; the temperature is raised by 4.0 ℃ per hour at the temperature of 701 plus 800 ℃, the fluctuation range is +/-10 ℃ when the temperature is used for 25 hours, the temperature is raised by 6.7 ℃ per hour at the temperature of 801 plus 1000 ℃, the fluctuation range is +/-20 ℃ when the temperature is used for 30 hours; the temperature is raised by 10 ℃ per hour at the temperature of 1000-1250 ℃, the temperature is raised by 30 hours, and the fluctuation range is +/-20 ℃; naturally cooling at a cooling speed of not more than 20 ℃/h and below 800 ℃ after stopping the furnace, discharging at a temperature of not more than 500 ℃, cleaning the surface after discharging, and checking to obtain a primary roasting piece;
5) primary impregnation: preheating the primary roasting piece at the temperature of 350-425 ℃ for 7.5 hours, keeping the temperature for 4 hours, then placing the primary roasting piece into an impregnation tank, vacuumizing to-0.088-0.092 Mpa for 10 minutes, injecting impregnated asphalt into the tank, pressurizing to 1.8Mpa, maintaining the pressure for 2.5 hours, finally extracting the asphalt, injecting cooling water, and taking out the asphalt from the tank to obtain a primary impregnated product;
6) secondary roasting: placing the dipped article into an open roasting furnace for secondary roasting, wherein the temperature rise curve uses a curve of 420 hours: firstly, the temperature is raised from room temperature to 130 ℃, the temperature is raised to 3.43 ℃ per hour at the temperature of 130-; the temperature is raised to 1.53 ℃ per hour at 351-400 ℃, the temperature is raised to 32 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 1.24 ℃ per hour at the temperature of 401 ℃ and 500 ℃ and the fluctuation range is +/-10 ℃ when the temperature is 88 hours; the temperature is raised by 1.24 ℃ per hour at the temperature of 501-600 ℃, the temperature is raised by 80 hours, and the fluctuation range is +/-10 ℃; the temperature is raised to 1.76 ℃ per hour at the temperature of 601-700 ℃, the temperature is raised to 64 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 4.13 ℃ per hour at the temperature of 701 plus 800 ℃, the temperature is raised to 24 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 6.18 ℃ per hour at the temperature of 801-; stopping the furnace, cooling, wherein the temperature of the product discharged from the furnace is not more than 450 ℃, cleaning the surface, and inspecting to obtain a secondary roasting piece;
7) secondary impregnation: preheating the secondary roasting piece at the temperature of 350-425 ℃ for 7.5 hours, keeping the temperature constant for 4 hours, then placing the secondary roasting piece into an impregnation tank, vacuumizing to-0.088-0.092 Mpa, keeping the pressure for 2.5 hours after vacuumizing for 10 minutes, injecting impregnated asphalt into the tank, pressurizing to 1.8Mpa, keeping the pressure, finally extracting the asphalt, injecting cooling water, and taking the asphalt out of the tank to obtain a secondary impregnated product;
8) and (3) roasting for three times: placing the secondary dipped product into an open roasting furnace for carrying out tertiary roasting, wherein a temperature rise curve uses a 420-hour curve, a process curve is the same as that of the secondary roasting, and inspecting the tertiary roasted product to obtain a tertiary roasted part;
9) graphitization treatment: placing the qualified tertiary roasted part into a 16500KVA Acheson furnace, carrying out power transmission graphitization treatment according to a set graphitization power transmission curve under the condition of air isolation, allowing the power to be controlled to be + 10% of the upper limit of a standard line and-5% of the lower limit of the standard line in the power transmission operation process, and sampling and inspecting the graphitized part after discharging;
graphitized power transmission curve: transmitting power according to the initial power of 2500KWh, transmitting power of 120KWh per hour in the period of 0-15 hours, transmitting power of 250KWh per hour in the period of 16-43 hours, freely rising after 44 hours, determining the power transmission ending time according to the process unit consumption and the furnace resistance, wherein the process unit consumption is 4800-;
10) and machining to obtain the ultrahigh-power graphite electrode joint.
Compared with the prior art, the invention has the beneficial effects that:
1. in the production process of producing the graphite electrode joint, domestic high-quality calcined coke is selected to replace a part of needle coke, and p-methylbenzaldehyde and p-toluenesulfonic acid are added as asphalt additives in the kneading stage, so that the carbon residue rate of the adhesive asphalt in the roasting procedure can be increased, the volume density and the breaking strength of the graphite electrode are further improved, and the performance of the ultrahigh-power graphite electrode joint is improved;
2. the small-particle-fraction material and the powder are increased, the strength of the carbonaceous raw material is improved, the volume density of the product is improved, the internal defects of the product are reduced, and the flexural strength of the product is improved. On the premise of considering the volume density and the breaking strength, the elastic modulus and the thermal expansion coefficient of the product still need to be balanced, and the phenomenon that the product is brittle and easy to break due to too high elastic modulus and thermal expansion coefficient of the product is avoided, so that the dosage of the needle coke of 1-2mm is properly increased.
The volume density and the breaking strength of the graphite electrode joint produced by the process steps are improved compared with the graphite electrode joint produced without adding p-tolualdehyde and p-toluenesulfonic acid, various physical and chemical indexes of the product are superior to those of the graphite electrode joint produced by completely using needle coke, the high-grade product rate is greatly improved, the comprehensive yield reaches above 63 percent, the yield is improved by 8 percent compared with the joint produced by completely using needle coke without adding an asphalt additive, and the production cost is greatly reduced.
Detailed Description
The present invention will be described in further detail with reference to examples.
A method for producing medium and small-sized ultrahigh-power graphite electrode joints, wherein: is prepared from the following raw materials: 45 parts by weight of needle coke, 55 parts by weight of calcined coke powder, 25 parts by weight of asphalt binder and 0.5 part by weight of Fe2O3An additive;
the needle coke comprises 17 parts by weight of needle coke with the particle size of 1-2mm, 15 parts by weight of needle coke with the particle size of 0.5-1mm and 13 parts by weight of needle coke with the particle size of 0-0.5 mm; the asphalt binder is added with methyl benzaldehyde and p-toluenesulfonic acid, wherein the weight of the added methyl benzaldehyde accounts for 2-3% of the weight of the asphalt binder, and the weight of the added p-toluenesulfonic acid accounts for 2-3% of the weight of the asphalt binder.
Furthermore, the ultrahigh power graphite electrode joint refers to a graphite electrode joint with the diameter of less than or equal to 289 mm.
A preparation process of an ultrahigh-power graphite electrode joint comprises the following steps: the method comprises the following process steps:
1) preparing materials: selecting 17 parts by weight of needle coke with the grain diameter of 1-2mm, 15 parts by weight of needle coke with the grain diameter of 0.5-1mm, 13 parts by weight of needle coke with the grain diameter of 0-0.5mm, 55 parts by weight of calcined coke powder and 0.5 part by weight of Fe2O3As an aggregate;
2) kneading and making paste: heating the aggregate to 110 ℃, then unloading the aggregate into a kneading pot, performing dry mixing for 10-15 minutes until the temperature reaches 140-;
3) extrusion molding: feeding the cooled paste obtained in the step 2) into a 2500T press, vacuumizing and tamping a material chamber of the press at the temperature of 135-140 ℃, keeping the vacuum degree above 0.8Mbar for not less than 3 minutes, tamping at the tamping pressure of 220KG, keeping the pressure at the pressure of 240KG for not less than 5 minutes, extruding the material at the extrusion speed of 15mm/s after the tamping drum is finished to prepare a pressed product, wherein the volume density is not less than 1.80g/cm3；
4) Primary roasting: the pressed product is put into a ring type roasting furnace with a cover for primary roasting, and the temperature rise curve uses a 420-hour curve: firstly, raising the temperature from room temperature to 130 ℃, raising the temperature by 4.4 ℃ per hour at the temperature of 130-; the temperature is raised to 1.4 ℃ per hour at 351-400 ℃, the temperature is raised to 35 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 0.8 ℃ per hour at 4.1-500 ℃, the temperature is raised to 120 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised by 1.4 ℃ per hour at the temperature of 501-600 ℃, the temperature is raised by 70 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised by 2.5 ℃ per hour at the temperature of 601-700 ℃, the temperature is raised for 40 hours, and the fluctuation range is +/-10 ℃; the temperature is raised by 4.0 ℃ per hour at the temperature of 701 plus 800 ℃, the fluctuation range is +/-10 ℃ when the temperature is used for 25 hours, the temperature is raised by 6.7 ℃ per hour at the temperature of 801 plus 1000 ℃, the fluctuation range is +/-20 ℃ when the temperature is used for 30 hours; the temperature is raised by 10 ℃ per hour at the temperature of 1000-1250 ℃, the temperature is raised by 30 hours, and the fluctuation range is +/-20 ℃; naturally cooling at a cooling speed of not more than 20 ℃/h and below 800 ℃ after stopping the furnace, discharging at a temperature of not more than 500 ℃, cleaning the surface after discharging, and checking to obtain a primary roasting piece;
5) primary impregnation: preheating the primary roasting piece at the temperature of 350-425 ℃ for 7.5 hours, keeping the temperature for 4 hours, then placing the primary roasting piece into an impregnation tank, vacuumizing to-0.088-0.092 Mpa for 10 minutes, injecting impregnated asphalt into the tank, pressurizing to 1.8Mpa, maintaining the pressure for 2.5 hours, finally extracting the asphalt, injecting cooling water, and taking out the asphalt from the tank to obtain a primary impregnated product;
6) secondary roasting: placing the dipped article into an open roasting furnace for secondary roasting, wherein the temperature rise curve uses a curve of 420 hours: firstly, the temperature is raised from room temperature to 130 ℃, the temperature is raised to 3.43 ℃ per hour at the temperature of 130-; the temperature is raised to 1.53 ℃ per hour at 351-400 ℃, the temperature is raised to 32 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 1.24 ℃ per hour at the temperature of 401 ℃ and 500 ℃ and the fluctuation range is +/-10 ℃ when the temperature is 88 hours; the temperature is raised by 1.24 ℃ per hour at the temperature of 501-600 ℃, the temperature is raised by 80 hours, and the fluctuation range is +/-10 ℃; the temperature is raised to 1.76 ℃ per hour at the temperature of 601-700 ℃, the temperature is raised to 64 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 4.13 ℃ per hour at the temperature of 701 plus 800 ℃, the temperature is raised to 24 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 6.18 ℃ per hour at the temperature of 801-; stopping the furnace, cooling, wherein the temperature of the product discharged from the furnace is not more than 450 ℃, cleaning the surface, and inspecting to obtain a secondary roasting piece;
7) secondary impregnation: preheating the secondary roasting piece at the temperature of 350-425 ℃ for 7.5 hours, keeping the temperature constant for 4 hours, then placing the secondary roasting piece into an impregnation tank, vacuumizing to-0.088-0.092 Mpa, keeping the pressure for 2.5 hours after vacuumizing for 10 minutes, injecting impregnated asphalt into the tank, pressurizing to 1.8Mpa, keeping the pressure, finally extracting the asphalt, injecting cooling water, and taking the asphalt out of the tank to obtain a secondary impregnated product;
8) and (3) roasting for three times: placing the secondary dipped product into an open roasting furnace for carrying out tertiary roasting, wherein a temperature rise curve uses a 420-hour curve, a process curve is the same as that of the secondary roasting, and inspecting the tertiary roasted product to obtain a tertiary roasted part;
9) graphitization treatment: placing the qualified tertiary roasted part into a 16500KVA Acheson furnace, carrying out power transmission graphitization treatment according to a set graphitization power transmission curve under the condition of air isolation, allowing the power to be controlled to be + 10% of the upper limit of a standard line and-5% of the lower limit of the standard line in the power transmission operation process, and sampling and inspecting the graphitized part after discharging;
graphitized power transmission curve: transmitting power according to the initial power of 2500KWh, transmitting power of 120KWh per hour in the period of 0-15 hours, transmitting power of 250KWh per hour in the period of 16-43 hours, freely rising after 44 hours, determining the power transmission ending time according to the process unit consumption and the furnace resistance, wherein the process unit consumption is 4800-;
10) and machining to obtain the ultrahigh-power graphite electrode joint. The detection shows that the volume density of the joint produced by the method is more than 1.83g/cm3, the breaking strength is more than 28MPa, and the resistance is less than 3.5 mu omega.
Claims (3)
1. An ultra-high power graphite electrode joint, characterized in that: is prepared from the following raw materials: 45 parts by weight of needle coke, 55 parts by weight of calcined coke powder, 25 parts by weight of asphalt binder and 0.5 part by weight of Fe2O3An additive;
the needle coke comprises 17 parts by weight of needle coke with the particle size of 1-2mm, 15 parts by weight of needle coke with the particle size of 0.5-1mm and 13 parts by weight of needle coke with the particle size of 0-0.5 mm; the asphalt binder is added with methyl benzaldehyde and p-toluenesulfonic acid, wherein the weight of the added methyl benzaldehyde accounts for 2-3% of the weight of the asphalt binder, and the weight of the added p-toluenesulfonic acid accounts for 2-3% of the weight of the asphalt binder.
2. The ultra-high power graphite electrode joint of claim 1, wherein: the ultrahigh power graphite electrode joint refers to a graphite electrode joint with the diameter less than or equal to 289 mm.
3. The process for preparing the ultra-high power graphite electrode joint as claimed in claim 1, wherein: the method comprises the following process steps:
1) preparing materials: selecting 17 parts by weight of needle coke with the grain diameter of 1-2mm, 15 parts by weight of needle coke with the grain diameter of 0.5-1mm, 13 parts by weight of needle coke with the grain diameter of 0-0.5mm, 55 parts by weight of calcined coke powder and 0.5 part by weight of Fe2O3As an aggregate;
2) kneading and making paste: heating the aggregate to 110 ℃, then unloading the aggregate into a kneading pot, performing dry mixing for 10-15 minutes until the temperature reaches 140-;
3) extrusion molding: feeding the cooled paste obtained in the step 2) into a 2500T press, vacuumizing and tamping a material chamber of the press at the temperature of 135-140 ℃, keeping the vacuum degree above 0.8Mbar for not less than 3 minutes, tamping at the tamping pressure of 220KG, keeping the pressure at the pressure of 240KG for not less than 5 minutes, extruding the material at the extrusion speed of 15mm/s after the tamping drum is finished to prepare a pressed product, wherein the volume density is not less than 1.80g/cm3；
4) Primary roasting: the pressed product is put into a ring type roasting furnace with a cover for primary roasting, and the temperature rise curve uses a 420-hour curve: firstly, raising the temperature from room temperature to 130 ℃, raising the temperature by 4.4 ℃ per hour at the temperature of 130-; the temperature is raised to 1.4 ℃ per hour at 351-400 ℃, the temperature is raised to 35 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 0.8 ℃ per hour at 4.1-500 ℃, the temperature is raised to 120 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised by 1.4 ℃ per hour at the temperature of 501-600 ℃, the temperature is raised by 70 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised by 2.5 ℃ per hour at the temperature of 601-700 ℃, the temperature is raised for 40 hours, and the fluctuation range is +/-10 ℃; the temperature is raised by 4.0 ℃ per hour at the temperature of 701 plus 800 ℃, the fluctuation range is +/-10 ℃ when the temperature is used for 25 hours, the temperature is raised by 6.7 ℃ per hour at the temperature of 801 plus 1000 ℃, the fluctuation range is +/-20 ℃ when the temperature is used for 30 hours; the temperature is raised by 10 ℃ per hour at the temperature of 1000-1250 ℃, the temperature is raised by 30 hours when the temperature is used, and the fluctuation range is +/-20 ℃; naturally cooling at a cooling speed of not more than 20 ℃/h and below 800 ℃ after stopping the furnace, discharging at a temperature of not more than 500 ℃, cleaning the surface after discharging, and checking to obtain a primary roasting piece;
5) primary impregnation: preheating the primary roasted part at the temperature of 350-425 ℃ for 7.5 hours, keeping the temperature for 4 hours, then placing the primary roasted part into an impregnation tank, vacuumizing to-0.088-0.092 Mpa for 10 minutes, then injecting impregnating asphalt into the tank, pressurizing to 1.8Mpa, maintaining the pressure for 2.5 hours, finally extracting the asphalt, injecting cooling water, and taking out the primary impregnated part from the tank to obtain a primary impregnated product;
6) secondary roasting: placing the dipped article into an open roasting furnace for secondary roasting, wherein the temperature rise curve uses a curve of 420 hours: firstly, the temperature is raised from room temperature to 130 ℃, the temperature is raised to 3.43 ℃ per hour at the temperature of 130-; the temperature is raised to 1.53 ℃ per hour at 351-400 ℃, the temperature is raised to 32 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 1.24 ℃ per hour at the temperature of 401 ℃ and 500 ℃ and the fluctuation range is +/-10 ℃ when the temperature is 88 hours; the temperature is raised by 1.24 ℃ per hour at the temperature of 501-600 ℃, the temperature is raised by 80 hours, and the fluctuation range is +/-10 ℃; the temperature is raised to 1.76 ℃ per hour at the temperature of 601-700 ℃, the temperature is raised to 64 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 4.13 ℃ per hour at the temperature of 701 plus 800 ℃, the temperature is raised to 24 hours when the temperature is used, and the fluctuation range is +/-10 ℃; the temperature is raised to 6.18 ℃ per hour at the temperature of 801-; stopping the furnace, cooling, wherein the temperature of the product discharged from the furnace is not more than 450 ℃, cleaning the surface, and inspecting to obtain a secondary roasting piece;
7) secondary impregnation: preheating the secondary roasting piece at the temperature of 350-425 ℃ for 7.5 hours, keeping the temperature for 4 hours, then placing the secondary roasting piece into an impregnation tank, vacuumizing to-0.088-0.092 Mpa, keeping the pressure for 2.5 hours after vacuumizing for 10 minutes, injecting impregnating asphalt into the tank, pressurizing to 1.8Mpa, keeping the pressure, and finally extracting the asphalt, injecting cooling water and taking the asphalt out of the tank to obtain a secondary impregnation product;
8) and (3) roasting for three times: placing the secondary dipped product into an open roasting furnace for carrying out tertiary roasting, wherein a temperature rise curve uses a 420-hour curve, a process curve is the same as that of the secondary roasting, and inspecting the tertiary roasted product to obtain a tertiary roasted product;
9) graphitization treatment: placing the qualified tertiary roasted part into a 16500KVA Acheson furnace, carrying out power transmission graphitization treatment according to a set graphitization power transmission curve under the condition of air isolation, allowing the power to be controlled to be + 10% of the upper limit of a standard line and-5% of the lower limit of the standard line in the power transmission operation process, and sampling and inspecting the graphitized part after discharging;
graphitized power transmission curve: transmitting power according to the initial power of 2500KWh, transmitting power of 120KWh per hour in the period of 0-15 hours, transmitting power of 250KWh per hour in the period of 16-43 hours, freely rising after 44 hours, determining the power transmission ending time according to the process unit consumption and the furnace resistance, wherein the process unit consumption is 4800-;
10) and machining to obtain the ultrahigh-power graphite electrode joint.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115259855A (en) * | 2021-04-30 | 2022-11-01 | 山西太谷明兴碳素玛钢有限公司 | Graphite crucible for producing lithium battery negative electrode material and preparation process thereof |
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