CN115259870A - Preparation process of graphite for single crystal thermal field - Google Patents
Preparation process of graphite for single crystal thermal field Download PDFInfo
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- CN115259870A CN115259870A CN202210903963.7A CN202210903963A CN115259870A CN 115259870 A CN115259870 A CN 115259870A CN 202210903963 A CN202210903963 A CN 202210903963A CN 115259870 A CN115259870 A CN 115259870A
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 31
- 239000010439 graphite Substances 0.000 title claims abstract description 30
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 30
- 239000013078 crystal Substances 0.000 title claims abstract description 19
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 239000000463 material Substances 0.000 claims abstract description 37
- 239000000843 powder Substances 0.000 claims abstract description 30
- 239000002006 petroleum coke Substances 0.000 claims abstract description 22
- 238000005087 graphitization Methods 0.000 claims abstract description 17
- 238000004898 kneading Methods 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims abstract description 13
- 238000001354 calcination Methods 0.000 claims abstract description 11
- 238000000227 grinding Methods 0.000 claims abstract description 10
- 238000002156 mixing Methods 0.000 claims abstract description 9
- 239000002994 raw material Substances 0.000 claims abstract description 7
- 239000002008 calcined petroleum coke Substances 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims description 23
- 238000001816 cooling Methods 0.000 claims description 21
- 238000001125 extrusion Methods 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 9
- 239000010426 asphalt Substances 0.000 claims description 8
- 238000007599 discharging Methods 0.000 claims description 8
- 230000008569 process Effects 0.000 claims description 7
- 238000012216 screening Methods 0.000 claims description 7
- 239000000498 cooling water Substances 0.000 claims description 6
- 238000005470 impregnation Methods 0.000 claims description 6
- 238000007689 inspection Methods 0.000 claims description 5
- 238000011068 loading method Methods 0.000 claims description 5
- 238000003825 pressing Methods 0.000 claims description 5
- 238000009210 therapy by ultrasound Methods 0.000 claims description 5
- 239000000853 adhesive Substances 0.000 claims description 4
- 230000001070 adhesive effect Effects 0.000 claims description 4
- 238000003754 machining Methods 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 4
- 235000021355 Stearic acid Nutrition 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 claims description 3
- 238000007598 dipping method Methods 0.000 claims description 3
- 238000007580 dry-mixing Methods 0.000 claims description 3
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 claims description 3
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 239000000779 smoke Substances 0.000 claims description 3
- 239000008117 stearic acid Substances 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims 1
- 235000012438 extruded product Nutrition 0.000 claims 1
- 238000002791 soaking Methods 0.000 claims 1
- 239000011230 binding agent Substances 0.000 abstract description 4
- 239000011300 coal pitch Substances 0.000 abstract description 2
- 238000004939 coking Methods 0.000 abstract description 2
- 238000007873 sieving Methods 0.000 abstract description 2
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000007767 bonding agent Substances 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 239000007770 graphite material Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000011295 pitch Substances 0.000 description 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 235000019580 granularity Nutrition 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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- 235000019786 weight gain Nutrition 0.000 description 1
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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
- C04B35/66—Monolithic refractories or refractory mortars, including those whether or not containing clay
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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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
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- C04B35/64—Burning or sintering processes
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- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
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- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
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Abstract
The invention discloses a preparation process of graphite for a single crystal thermal field, which relates to the technical field of graphite preparation and comprises the following process steps: preparing materials: selecting petroleum coke as a raw material, conveying the petroleum coke into crushing equipment for crushing, then conveying the crushed petroleum coke into a calcining furnace for calcining, and conveying the calcined petroleum coke into a pulverizer for grinding into powder; has the advantages that: the graphite for the single crystal thermal field is prepared by taking petroleum coke as a raw material, crushing and calcining the petroleum coke, grinding the petroleum coke into powder, sieving the powder, mixing the powder, taking medium-temperature modified coal pitch with the softening point of 95-105 ℃ and the coking value of more than or equal to 58% as a binder, kneading, extruding and forming, and optimizing a roasting temperature-rise curve and a graphitization temperature-rise curve.
Description
Technical Field
The invention relates to the technical field of graphite preparation, in particular to a preparation process of graphite for a single crystal thermal field.
Background
The high-purity graphite has the advantages of high temperature resistance, corrosion resistance, thermal shock resistance, small thermal expansion coefficient, self-lubrication, small resistance coefficient, easy machining and the like, is widely applied to the fields of metallurgy, machinery, environmental protection, chemical industry, electronics, medicine, war industry, aerospace and the like, and has increasingly important status in national economy, particularly in the solar photovoltaic industry. The average annual growth rate of the global solar photovoltaic industry is 40%, china, as the largest solar photovoltaic producing country around the world, has the share of 70% of the world, and the high-grade graphite material consumed in 2011 by the industry reaches more than 2.3 ten thousand, so that the demand of monocrystalline silicon and polycrystalline silicon of the photovoltaic industry on the high-purity graphite material is expected to increase at a speed of 20% -25% per year in future;
the monocrystalline silicon is pulled by a polycrystalline silicon Czochralski method, the monocrystalline silicon is mainly applied to a semiconductor element in the electronic industry, is one of the most basic materials in the electronic industry, is expected to keep the growth rate above two digits, occupies a half-wall Jiangshan in a photovoltaic cell due to high-efficiency conversion efficiency, is a heating generation furnace produced by the monocrystalline silicon Czochralski method, but is complex in process and low in production efficiency when the existing monocrystalline thermal field graphite is produced, and the performance of the prepared monocrystalline thermal field graphite is low.
Disclosure of Invention
The invention aims to solve the problems that in the prior art, when single crystal thermal field graphite is produced, the technological process is complex, the production efficiency is low, and the performance of the prepared single crystal thermal field graphite is low, and provides a preparation technology of graphite for a single crystal thermal field.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation process of graphite for a single crystal thermal field comprises the following process steps: 1) Preparing materials: selecting petroleum coke as a raw material, conveying the petroleum coke into crushing equipment for crushing, then conveying the crushed petroleum coke into a calcining furnace for calcining, conveying the calcined petroleum coke into a pulverizer for grinding into powder, and then screening the powder;
2) Kneading: adding the sieved powder into a kneading pot at 178 ℃, dry-mixing for 50 minutes by a stirring knife at the speed of 9r/min until the temperature of the powder reaches 140 ℃, then adding a bonding agent into the kneading pot, wet-mixing for 20 minutes by the stirring knife at the speed of 9r/0min, adding stearic acid which is 0.15 percent of the total weight of the materials into the kneading pot, continuously wet-mixing, discharging paste after 15 minutes, and finally discharging the paste at the temperature of 170 ℃; after paste is discharged, the paste material is put into a material airing pot with the pot temperature of 35 ℃ and the stirring knife rotating speed of 9r/min for airing for 23 minutes until the paste material is cooled to 131 ℃;
3) Extrusion forming: conveying the aired paste material in the step 2) to a material chamber of a 41MN horizontal extruder by using a belt blanking machine, wherein each pot is used for 12 minutes; the temperature of a material chamber of the press is kept at 138 ℃, the temperature of an initial deformation section is kept at 165 ℃, the temperature of a nozzle is kept at 178 ℃, and the temperature of a nozzle is kept at 170 ℃; after the first pot is fed, vacuumizing a material chamber to remove smoke of the paste, when the vacuum degree reaches 50Mbar, tamping by using a press, keeping the tamping pressure at 260Mbar for 2 minutes, then continuously loading the dried paste in the second pot, vacuumizing the material chamber after the feeding is finished, prepressing when the vacuum degree reaches 50Mbar, and keeping the prepressing pressure at 300Mbar for 5 minutes; after the pre-pressing is finished, the nozzle baffle can be put down to start the extrusion operation, 3 pieces of materials can be extruded in each cylinder, and the extrusion pressure is respectively 68Mbar, 66Mbar and 65Mbar; rolling into a cooling water tank at 32 ℃ after each extrusion is finished, cooling for 8 hours, and then fishing out;
4) Primary roasting: standing the extrusion-molded product in the open air for 2 days, performing initial inspection, standing for 1 day, performing recheck, loading the extrusion-molded product into a ring type roasting furnace with a cover for primary roasting after the extrusion-molded product is qualified, wherein a temperature rise curve is 599 hours, and the temperature rises from room temperature to 350 ℃ for 1 hour; heating to 350-600 deg.C for 0.7-1.1 hr, heating to 278 hr, heating to 550-1000 deg.C for 1.2-1.6 hr, and heating for 320 hr; then cooling to 800 ℃ at the rate of 10 +/-5 ℃ per hour, naturally cooling for 168 hours to prepare a primary roasted product, and inspecting the primary roasted product;
5) Dipping: placing the qualified primary roasting piece into a 390 ℃ preheating tank for constant-temperature preheating for 8 hours, then placing the primary roasting piece into an impregnation tank, firstly vacuumizing to-90 kpa and maintaining the vacuum for 90 minutes, then injecting impregnated asphalt to pressurize to 1.83Mpa, maintaining the pressure for 3 hours, finally extracting the asphalt, injecting cooling water for cooling, and taking out of the tank to obtain an impregnated product;
6) Secondary roasting: placing the dipped article into an open roasting furnace for secondary roasting, wherein a temperature rise curve is 599 hours and is raised from room temperature to 350 ℃ within 1 hour; heating to 350-600 deg.C for 0.7-1.1 hr, heating to 278 hr, heating to 550-1000 deg.C for 1.2-1.6 hr, and heating for 320 hr; then cooling to 800 ℃ at the rate of 10 +/-5 ℃ per hour, naturally cooling for 168 hours to prepare a secondary roasting piece, and inspecting a secondary roasting product;
7) Graphitization treatment: placing the qualified secondary roasting piece into an internal-heating serial-type graphitizing furnace for graphitization treatment, wherein the temperature rise speed is controlled to be 220-230 ℃/h at the room temperature-1200 ℃ stage, and the graphitization treatment is carried out for 5 hours; then, in the stage of 1200-1900 ℃, the temperature rising speed is controlled to be 100-110 ℃/h, and graphitization treatment is carried out for 6 hours; finally, in the stage of 1900-3000 ℃, the temperature rise speed is controlled to be 300-310 ℃/h, and graphitization treatment is carried out for 3.5 hours; after power transmission is finished, power is cut off, natural cooling is carried out for 7 days, then the graphite is discharged, and sampling inspection is carried out on the graphite treatment piece after the graphite is discharged;
8) And machining to obtain the formed graphite for the single crystal thermal field.
Preferably, the petroleum coke calcined in the step 1) is conveyed to a medium crushing device to be ground into powder, and then the powder is sieved.
Preferably, the binder in step 2) is medium-temperature modified asphalt.
Preferably, the impregnant is subjected to ultrasonic treatment before being injected into the impregnation tank.
Compared with the prior art, the invention provides a preparation process of graphite for a single crystal thermal field, which has the following beneficial effects: the graphite for the single crystal thermal field is prepared by taking petroleum coke as a raw material, crushing and calcining the petroleum coke, grinding the petroleum coke into powder, sieving the powder, mixing the powder, taking medium-temperature modified coal pitch with the softening point of 95-105 ℃ and the coking value of more than or equal to 58% as a binder, kneading, extruding and forming, and optimizing a roasting temperature-rise curve and a graphitization temperature-rise curve.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a process flow diagram of the present invention;
fig. 2 is a flow chart of an implementation of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Referring to fig. 1-2, a preparation process of graphite for a single crystal thermal field comprises the following steps: 1) Preparing materials: selecting petroleum coke as a raw material, conveying the petroleum coke into crushing equipment for crushing, then conveying the crushed petroleum coke into a calcining furnace for calcining, conveying the calcined petroleum coke into a pulverizer for grinding into powder, then screening the powder, and after crushing, calcining, grinding and screening, primarily treating the raw material so as to well obtain required ingredients;
2) Kneading: adding the sieved powder into a kneading pot at 178 ℃, dry-mixing for 50 minutes by a stirring knife at the speed of 9r/min until the temperature of the powder reaches 140 ℃, then adding a bonding agent into the kneading pot, wet-mixing for 20 minutes by the stirring knife at the speed of 9r/min, adding stearic acid which is 0.15 percent of the total weight of the materials into the kneading pot, continuously wet-mixing, discharging paste after 15 minutes, and finally discharging the paste at the temperature of 170 ℃; after paste discharging, putting the paste material into a material airing pot with the pot temperature of 35 ℃ and the stirring cutter rotating speed of 9r/min for airing for 23 minutes until the paste material is cooled to 131 ℃, and mixing the powder material with the binder according to the ratio of 77.5;
3) Extrusion forming: conveying the paste aired in the step 2) to a material chamber of a 41MN horizontal extruder by using a belt blanking machine, wherein the time of each pot is 12 minutes; the temperature of a material chamber of the press is kept at 138 ℃, the temperature of an initial deformation section is kept at 165 ℃, the temperature of a nozzle is kept at 178 ℃, and the temperature of a nozzle is kept at 170 ℃; after the first pot is fed, vacuumizing the material chamber to remove smoke of paste, when the vacuum degree reaches 50Mbar, tamping by using a press, keeping the tamping pressure at 260Mbar for 2 minutes, then continuously filling the dried paste in the second pot, after the feeding is finished, vacuumizing the material chamber, when the vacuum degree reaches 50Mbar, pre-pressing, and keeping the pre-pressing pressure at 300Mbar for 5 minutes; after the pre-pressing is finished, the nozzle baffle can be put down to start the extrusion operation, 3 pieces of materials can be extruded in each cylinder, and the extrusion pressure is 68Mbar, 66Mbar and 65Mbar respectively; after each extrusion is finished, rolling the extruded paste into a 32 ℃ cooling water tank to be cooled for 8 hours, and then fishing out the paste, so that the yield and the physical performance of the formed green body can be improved after the paste is pre-pressed;
4) Primary roasting: standing the extrusion-molded product in the open air for 2 days, performing initial inspection, standing for 1 day, performing recheck, loading the extrusion-molded product into a ring type roasting furnace with a cover for primary roasting after the extrusion-molded product is qualified, wherein a temperature rise curve is 599 hours, and the temperature rises from room temperature to 350 ℃ for 1 hour; raising the temperature by 0.7-1.1 ℃ per hour at 350-600 ℃, and when the temperature is used for 278 hours, the semicoke begins to form at the stage, and the slow temperature rise is beneficial to improving the coke yield of the roasted product, so that the volume density and the strength of the roasted product are improved, and cracks are effectively avoided, and when the temperature is 550-1000 ℃, the temperature is raised by 1.2-1.6 ℃ per hour, and when the temperature is used for 320 hours; then cooling to 800 ℃ at the rate of 10 +/-5 ℃ per hour, naturally cooling, and cooling for 168 hours to obtain a primary roasted product, and inspecting the primary roasted product, wherein the inspection result is as follows: bulk density: 1.69 to 1.71g/cm3, resistivity: 34-35 mu omega.m, the actual yield is 92.86%, the length is contracted by 1.87%, and the outer diameter is contracted by 1%;
5) Dipping: placing the qualified primary roasting piece into a 390 ℃ preheating tank for constant-temperature preheating for 8 hours, then placing the primary roasting piece into an impregnation tank, firstly vacuumizing to-90 kpa and maintaining the vacuum for 90 minutes, then injecting impregnating pitch to pressurize to 1.83Mpa, maintaining the pressure for 3 hours, finally extracting the pitch, injecting cooling water for cooling, and taking out of the tank to obtain an impregnated product, wherein the weight gain rate of the impregnated product is more than 12%;
6) Secondary roasting: placing the dipped article into an open roasting furnace for secondary roasting, wherein a temperature rise curve is 599 hours and is raised from room temperature to 350 ℃ within 1 hour; heating to 350-600 deg.C for 0.7-1.1 hr, heating to 278 hr, heating to 550-1000 deg.C for 1.2-1.6 hr, and heating for 320 hr; then cooling to 800 ℃ at the rate of 10 +/-5 ℃ per hour, naturally cooling for 168 hours to prepare a secondary roasting product, inspecting the secondary roasting product, and roasting again to carbonize the adhesive asphalt and form a carbon coke network among the powder so as to firmly bond the powder with different granularities into a whole;
7) Graphitization treatment: placing the qualified secondary roasting piece into an internal-heating serial-type graphitizing furnace for graphitization, wherein the temperature rise speed is controlled to be 220-230 ℃/h at the room temperature-1200 ℃ stage, and the graphitization is carried out for 5 hours; then, in the stage of 1200-1900 ℃, the temperature rising speed is controlled to be 100-110 ℃/h, and graphitization treatment is carried out for 6 hours; finally, in the stage of 1900-3000 ℃, the temperature rise speed is controlled to be 300-310 ℃/h, and graphitization treatment is carried out for 3.5 hours; and (3) after power failure and natural cooling for 7 days after power transmission, discharging the graphitized processing piece out of the furnace, and sampling and inspecting the graphitized processing piece, wherein the sampling and inspecting results are as follows: bulk density: 1.76 to 1.77g/cm3, resistivity: 4.7-4.9 μ Ω · m, coefficient of thermal expansion: 1.43X 10-6/DEG C, flexural strength of 10.94-11.02MPa, modulus of elasticity: 12.1-12.6Gpa, ash: 0.03 percent;
8) Machining to obtain graphite for the formed single crystal thermal field, and measuring the resistivity to be 4.5-4.7 mu omega-m in real time;
conveying the petroleum coke calcined in the step 1) to intermediate crushing equipment, grinding the petroleum coke into powder, screening the powder, or grinding the petroleum coke into powder in the intermediate crushing equipment, and then screening the powder;
the adhesive in the step 2) is medium-temperature modified asphalt, so that the bonding degree is better;
the impregnant is subjected to ultrasonic treatment before being injected into the impregnation tank, so that the aggregation of insoluble components of heavy oil in the impregnation process of the asphalt is reduced, and the viscosity of the asphalt is reduced at the same time, wherein in the embodiment, the ultrasonic treatment energy is 38J, and the ultrasonic treatment time is 30min.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without being mutually inconsistent.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (4)
1. A preparation process of graphite for a single crystal thermal field is characterized by comprising the following steps: the method comprises the following process steps:
1) Preparing materials: selecting petroleum coke as a raw material, conveying the petroleum coke into crushing equipment for crushing, then conveying the crushed petroleum coke into a calcining furnace for calcining, conveying the calcined petroleum coke into a pulverizer for grinding into powder, and then screening the powder;
2) Kneading: adding the sieved powder into a kneading pot at 178 ℃, dry-mixing for 50 minutes by a stirring knife at the speed of 9r/min until the temperature of the powder reaches 140 ℃, then adding an adhesive into the kneading pot, wet-mixing for 20 minutes by the stirring knife at the speed of 9r/0min, adding stearic acid accounting for 0.15 percent of the total weight of the materials into the kneading pot, then continuing wet-mixing, discharging paste after 15 minutes, and finally discharging the paste at the temperature of 170 ℃; after paste is discharged, the paste material is put into a material airing pot with the pot temperature of 35 ℃ and the stirring knife rotating speed of 9r/min for airing for 23 minutes until the paste material is cooled to 131 ℃;
3) Extrusion molding: conveying the aired paste material in the step 2) to a material chamber of a 41MN horizontal extruder by using a belt blanking machine, wherein each pot is used for 12 minutes; the temperature of a material chamber of the press is kept at 138 ℃, the temperature of an initial deformation section is kept at 165 ℃, the temperature of a nozzle is kept at 178 ℃, and the temperature of a nozzle is kept at 170 ℃; after the first pot is fed, vacuumizing a material chamber to remove smoke of the paste, when the vacuum degree reaches 50Mbar, tamping by using a press, keeping the tamping pressure at 260Mbar for 2 minutes, then continuously loading the dried paste in the second pot, vacuumizing the material chamber after the feeding is finished, prepressing when the vacuum degree reaches 50Mbar, and keeping the prepressing pressure at 300Mbar for 5 minutes; after the pre-pressing is finished, the nozzle baffle can be put down to start the extrusion operation, 3 pieces of materials can be extruded in each cylinder, and the extrusion pressure is respectively 68Mbar, 66Mbar and 65Mbar; rolling into a cooling water tank at 32 ℃ after each extrusion is finished, cooling for 8 hours, and then fishing out;
4) Primary roasting: standing the extruded product in the open air for 2 days, performing initial detection, standing for 1 day, performing recheck, loading into a covered ring type roasting furnace for primary roasting after the product is qualified, wherein the temperature rise curve is 599 hours, and the temperature rises from room temperature to 350 ℃ for 1 hour; heating to 350-600 deg.C for 0.7-1.1 hr, heating to 278 hr, heating to 550-1000 deg.C for 1.2-1.6 hr, and heating for 320 hr; then cooling to 800 ℃ at the rate of 10 +/-5 ℃ per hour, naturally cooling for 168 hours to prepare a primary roasted product, and inspecting the primary roasted product;
5) Dipping: placing the qualified primary roasting piece into a 390 ℃ preheating tank for constant-temperature preheating for 8 hours, then placing the primary roasting piece into an impregnation tank, firstly vacuumizing to-90 kpa and maintaining the vacuum for 90 minutes, then injecting impregnating pitch for pressurizing to 1.83Mpa, maintaining the pressure for 3 hours, finally extracting the pitch, injecting cooling water for cooling, and taking out of the tank to obtain an impregnated product;
6) Secondary roasting: placing the dipped product into an open roasting furnace for secondary roasting, wherein a temperature rise curve uses a 599-hour curve, and the temperature rises from room temperature to 350 ℃ for 1 hour; heating to 350-600 deg.C for 0.7-1.1 hr for 278 hr, and heating to 550-1000 deg.C for 1.2-1.6 hr for 320 hr; then cooling to 800 ℃ at the rate of 10 +/-5 ℃ per hour, naturally cooling for 168 hours to prepare a secondary roasted product, and inspecting the secondary roasted product;
7) Graphitization treatment: placing the qualified secondary roasting piece into an internal-heating serial-type graphitizing furnace for graphitization, wherein the temperature rise speed is controlled to be 220-230 ℃/h at the room temperature-1200 ℃ stage, and the graphitization is carried out for 5 hours; then, in the stage of 1200-1900 ℃, the temperature rising speed is controlled to be 100-110 ℃/h, and graphitization treatment is carried out for 6 hours; finally, in the 1900-3000 ℃ stage, the heating rate is controlled at 300-310 ℃/h, and graphitization treatment is carried out for 3.5 hours; after power transmission is finished, power is cut off, natural cooling is carried out for 7 days, then the graphite is discharged, and sampling inspection is carried out on the graphite treatment piece after the graphite is discharged;
8) And machining to obtain the formed graphite for the single crystal thermal field.
2. The process according to claim 1, wherein the graphite for single crystal thermal field is prepared by: conveying the calcined petroleum coke in the step 1) to intermediate crushing equipment, grinding the calcined petroleum coke into powder, and then screening the powder.
3. The process according to claim 1, wherein the graphite for single crystal thermal field is prepared by: the adhesive in the step 2) is medium-temperature modified asphalt.
4. The process according to claim 1, wherein the graphite for single crystal thermal field is prepared by: the impregnant is subjected to ultrasonic treatment before being injected into a soaking tank.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116903373A (en) * | 2023-07-28 | 2023-10-20 | 鄯善隆盛碳素制造有限公司 | Graphitized furnace end guard plate processing technology |
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| CN112521152A (en) * | 2020-10-21 | 2021-03-19 | 大同宇林德石墨新材料股份有限公司 | Preparation process of phi 700mm ultrahigh-power graphite electrode |
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