CN114349510A - Production process of isostatic pressing special graphite - Google Patents
Production process of isostatic pressing special graphite Download PDFInfo
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- CN114349510A CN114349510A CN202210040456.5A CN202210040456A CN114349510A CN 114349510 A CN114349510 A CN 114349510A CN 202210040456 A CN202210040456 A CN 202210040456A CN 114349510 A CN114349510 A CN 114349510A
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 82
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 63
- 239000010439 graphite Substances 0.000 title claims abstract description 63
- 238000000462 isostatic pressing Methods 0.000 title claims abstract description 59
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 20
- 239000010426 asphalt Substances 0.000 claims abstract description 85
- 238000004898 kneading Methods 0.000 claims abstract description 35
- 239000011329 calcined coke Substances 0.000 claims abstract description 30
- 238000000227 grinding Methods 0.000 claims abstract description 21
- 238000012216 screening Methods 0.000 claims abstract description 15
- 238000003756 stirring Methods 0.000 claims abstract description 12
- 238000000034 method Methods 0.000 claims abstract description 10
- 239000006253 pitch coke Substances 0.000 claims abstract description 5
- 239000000463 material Substances 0.000 claims description 59
- 238000001816 cooling Methods 0.000 claims description 57
- 238000007599 discharging Methods 0.000 claims description 28
- 239000000571 coke Substances 0.000 claims description 20
- 238000007598 dipping method Methods 0.000 claims description 20
- 239000006004 Quartz sand Substances 0.000 claims description 18
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 18
- 238000004140 cleaning Methods 0.000 claims description 18
- 238000011049 filling Methods 0.000 claims description 18
- 239000012774 insulation material Substances 0.000 claims description 18
- 238000011068 loading method Methods 0.000 claims description 16
- 238000007873 sieving Methods 0.000 claims description 14
- 238000005087 graphitization Methods 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 9
- 238000005086 pumping Methods 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 3
- 239000010959 steel Substances 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 claims description 2
- 239000000047 product Substances 0.000 abstract description 70
- 239000000843 powder Substances 0.000 abstract description 7
- 230000008569 process Effects 0.000 abstract description 6
- 238000002844 melting Methods 0.000 abstract description 4
- 230000008018 melting Effects 0.000 abstract description 4
- 239000000126 substance Substances 0.000 abstract description 4
- 239000011230 binding agent Substances 0.000 abstract description 3
- 238000009826 distribution Methods 0.000 abstract description 3
- 239000012466 permeate Substances 0.000 abstract description 3
- 239000002994 raw material Substances 0.000 abstract 1
- 238000002791 soaking Methods 0.000 abstract 1
- 239000003921 oil Substances 0.000 description 11
- 238000002156 mixing Methods 0.000 description 10
- 229910052799 carbon Inorganic materials 0.000 description 7
- 235000013312 flour Nutrition 0.000 description 6
- 239000003575 carbonaceous material Substances 0.000 description 2
- 238000007580 dry-mixing Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- -1 mould pressing Chemical compound 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
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- 239000010949 copper Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000010892 electric spark Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 229910021397 glassy carbon Inorganic materials 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
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- 230000003137 locomotive effect Effects 0.000 description 1
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- QLOAVXSYZAJECW-UHFFFAOYSA-N methane;molecular fluorine Chemical compound C.FF QLOAVXSYZAJECW-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention discloses a production process of isostatic pressing special graphite, which comprises the working procedures of crushing, grinding, kneading, screening, isostatic pressing, roasting, soaking and graphitizing, wherein the used raw materials comprise calcined coke, pitch coke and modified pitch. The modified asphalt powder is used as a binder, the calcined coke powder, the asphalt coke powder and the modified asphalt powder are simultaneously added into a kneading machine for stirring and kneading in the kneading process, the asphalt is gradually melted along with the rise of the temperature and uniformly permeates into the calcined coke and the asphalt coke powder, and part of the asphalt is uniformly coated on the surfaces of the calcined coke and the asphalt coke powder, so that the independent asphalt melting step is omitted, the distribution of the asphalt is more uniform, and the finished product rate and the physical and chemical performance index of the product are improved.
Description
Technical Field
The invention relates to the technical field of graphite production, in particular to a production process of isostatic pressing special graphite.
Background
The special graphite has a wide coverage range, and different understanding and classification methods are provided for the electric carbon product industry, the natural graphite product industry and the metallurgical carbon product industry, and the special graphite is a high-strength, high-density and high-purity graphite product (three-high graphite for short) and is explained in terms of the custom classification of the metallurgical carbon product industry. The three-high graphite can be divided into three types of coarse particle structures, fine particle structures and ultra-fine particle structures from the material organization structure; the forming method mainly includes three types of special graphite including mould pressing, extrusion and isostatic pressing, and in addition, the vibration forming can also be used for producing the special graphite.
The specific graphite in the broad sense also includes pyrolytic carbon (pyrolytic graphite), carbon materials for bioengineering, glassy carbon, porous carbon and graphite, graphite intercalation compounds (such as flexible graphite and graphite fluoride), graphite for laser, and the like, and the mechanical and electronic industry also uses a plurality of specific carbon and graphite materials, such as carbon brushes, carbon graphite bearings, feed sliders of electric locomotives, graphite molds for drawing optical fibers, and the like.
The high-quality special graphite, namely the isotropic graphite, is produced by an isostatic pressing process and is also called as isostatic pressing special graphite. The main applications of the composition are: special graphite for electric spark machining; manufacturing special graphite for a casting mold; special graphite for continuous casting of steel or copper and aluminum; high-purity graphite used for the Czochralski silicon furnace or smelting noble metal and high-purity materials; synthesizing graphite for artificial diamond; special graphite for rocket and missile technology.
The production process flow of the isostatic pressing special graphite sequentially comprises the following steps: crushing, primary grinding, kneading, cooling, secondary crushing, secondary grinding, screening, isostatic pressing, primary roasting, dipping, secondary roasting and graphitizing.
The mixing and kneading process comprises the steps of melting and precipitating asphalt for more than three days in advance to remove water and partial impurities in the asphalt, keeping the temperature of the melted asphalt at 150-260 ℃, preheating a mixing and kneading pot for more than 30 minutes when the mixing and kneading pot is started for the first time, adding dry powder for mixing and kneading when the temperature of an empty mixing and kneading pot is increased to more than 130 ℃, wherein the dry mixing time is about 30-60 minutes, the temperature of dry materials after dry mixing is about 130-200 ℃, mixing and kneading for 1-5 hours after asphalt is added, and the temperature of paste materials after the paste materials are taken out of the pot is 160-260 ℃.
The volume density and strength of the isostatic pressing graphite obtained by the isostatic pressing graphite preparation process in the prior art are still to be improved, and the yield of the isostatic pressing graphite in the processes of roasting, dipping, graphitizing and the like is also in urgent need of improvement.
Disclosure of Invention
In view of the above, the present invention is directed to the defects of the prior art, and the main object of the present invention is to provide a production process of isostatic pressing special graphite, which can improve the yield and the physical and chemical properties of the product.
In order to achieve the purpose, the invention adopts the following technical scheme:
a production process of isostatic pressing special graphite comprises the following steps:
(1) crushing and primary grinding: firstly, primarily crushing calcined coke, pitch coke and modified pitch to below 10mm by using a crusher respectively, and then crushing the crushed coke, the pitch coke and the modified pitch to the particle size of 10-20 microns by using a pulverizer respectively;
(2) kneading and cooling: the crushed calcined coke, the asphalt coke and the modified asphalt are mixed according to the weight ratio (20-40): (20-40): (25-50), heating the paste by using heat conducting oil for the kneading machine, wherein the temperature of the heat conducting oil is 180-260 ℃, and stirring and cooling the paste in a cooling machine after 1-5 hours of kneading;
(3) secondary crushing, secondary grinding and screening: putting the cooled paste into a crusher to be coarsely crushed to the granularity of below 10mm, crushing the paste to the granularity of 15-30 microns by using a pulverizer, and sieving the crushed material by using a sieving machine of 60-100 meshes;
(4) isostatic pressing: loading the screened materials into a rubber die sleeve, and hoisting the rubber die sleeve into an isostatic press after vibration and vacuum pumping; setting the pressure parameters of the isostatic pressing machine as follows: the maximum pressure is 60-200 MPa, the pressure maintaining time is 10-120 minutes, and the pressure relief time is 1-20 minutes;
(5) primary roasting: putting the green body subjected to isostatic pressing into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 200-1000 hours at the highest roasting temperature of 800-1250 ℃, cooling to a proper temperature, and discharging;
(6) dipping: cleaning the surface of a product after roasting and discharging, hanging the product into a preheating furnace, enabling the temperature of the preheating furnace to be 260-400 ℃, enabling the preheating time to be 2-10 hours, timely hanging the preheated product into a dipping tank, covering a tank cover, firstly vacuumizing to-0.098 MPa, keeping the vacuum for 10-90 minutes, injecting asphalt into the tank, pressurizing to 1.5-5.0 MPa, keeping the pressure for 1-5 hours, returning the asphalt, cooling, then opening the cover, and hanging the product out;
(7) secondary roasting: placing the dipped product into a roasting furnace, filling quartz sand around the green body, roasting for 100-500 hours at the highest temperature of 800-1150 ℃, cooling to a proper temperature, and discharging;
(8) and graphitizing to obtain the isostatic pressing special graphite.
As a preferable scheme, the calcined coke, the asphalt coke and the modified asphalt in the step (2) are mixed according to the weight ratio of 30: 38: 32.
as a preferable scheme, in the step (8), the graphitization is specifically: cleaning the side wall, the end wall and the furnace bottom of the furnace, and laying new furnace bottom materials again, wherein the height of the furnace bottom material layer is ensured to ensure that the center of the cross section of the furnace core is symmetrical to the center of the conductive electrode group of the end wall of the furnace end, and the furnace bottom is allowed to sink after being electrified, so that the height of the laid furnace bottom material layer is allowed to be 30-50 mm higher; putting products to be graphitized into a graphitizing furnace, wherein each group of products is separated by a resistance material, heat insulation materials are filled at two sides of the graphitizing furnace, and a layer of heat insulation material with the thickness of more than 750mm is covered on the top of the furnace; and (4) the power transmission time is 200-400 hours, the highest temperature is more than 2500 ℃, and the steel plate is discharged after being cooled.
Compared with the prior art, the invention has obvious advantages and beneficial effects, and specifically, the technical scheme includes that:
the modified asphalt powder is used as a binder, the calcined coke powder, the asphalt coke powder and the modified asphalt powder are simultaneously added into a kneading machine for stirring and kneading in the kneading process, the asphalt is gradually melted along with the rise of the temperature and uniformly permeates into the calcined coke and the asphalt coke powder, and part of the asphalt is uniformly coated on the surfaces of the calcined coke and the asphalt coke powder, so that the independent asphalt melting step is omitted, the distribution of the asphalt is more uniform, and the finished product rate and the physical and chemical performance index of the product are improved.
Detailed Description
The invention discloses a production process of isostatic pressing special graphite, which comprises the following steps:
(1) crushing and primary grinding: the calcined coke, the asphalt coke and the modified asphalt are firstly and primarily crushed to below 10mm by a crusher respectively, and then are respectively crushed to the particle size of 10-20 microns by a pulverizer respectively.
(2) Kneading and cooling: the crushed calcined coke, the asphalt coke and the modified asphalt are mixed according to the weight ratio (20-40): (20-40): (25-50), heating the paste by using heat conducting oil for the kneading machine, wherein the temperature of the heat conducting oil is 180-260 ℃, and after 1-5 hours of kneading, putting the paste into a cooling machine for stirring and cooling.
(3) Secondary crushing, secondary grinding and screening: and (3) putting the cooled paste into a crusher to be coarsely crushed to the granularity of below 10mm, crushing the paste to the granularity of 15-30 microns by using a pulverizer, and sieving the crushed material by using a sieving machine of 60-100 meshes.
(4) Isostatic pressing: loading the screened materials into a rubber die sleeve, and hoisting the rubber die sleeve into an isostatic press after vibration and vacuum pumping; setting the pressure parameters of the isostatic pressing machine as follows: the maximum pressure is 60-200 MPa, the pressure maintaining time is 10-120 minutes, and the pressure relief time is 1-20 minutes.
(5) Primary roasting: and (3) putting the green body subjected to isostatic pressing into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 200-1000 hours at the highest temperature of 800-1250 ℃, cooling to a proper temperature, and discharging.
(6) Dipping: cleaning the surface of a product after roasting and discharging, hanging the product into a preheating furnace, enabling the temperature of the preheating furnace to be 260-400 ℃, enabling the preheating time to be 2-10 hours, timely hanging the preheated product into a dipping tank, covering a tank cover, firstly vacuumizing to-0.098 MPa, keeping the vacuum for 10-90 minutes, injecting asphalt into the tank, pressurizing to 1.5-5.0 MPa, keeping the pressure for 1-5 hours, returning the asphalt, cooling, then opening the cover, and hanging the product out.
(7) Secondary roasting: and (3) loading the dipped product into a roasting furnace, filling quartz sand around the green body, roasting for 100-500 hours at the highest temperature of 800-1150 ℃, cooling to a proper temperature, and discharging.
(8) Graphitization: cleaning the side wall, the end wall and the furnace bottom of the furnace, and laying new furnace bottom materials again, wherein the height of the furnace bottom material layer is ensured to ensure that the center of the cross section of the furnace core is symmetrical to the center of the conductive electrode group of the end wall of the furnace end, and the furnace bottom is allowed to sink after being electrified, so that the height of the laid furnace bottom material layer is allowed to be 30-50 mm higher; putting products to be graphitized into a graphitizing furnace, wherein each group of products is separated by a resistance material, heat insulation materials are filled at two sides of the graphitizing furnace, and a layer of heat insulation material with the thickness of more than 750mm is covered on the top of the furnace; and (4) transmitting power for 200-400 hours, keeping the highest temperature higher than 2500 ℃, cooling, and discharging to obtain the isostatic pressing special graphite.
The invention is illustrated in more detail below in the following examples:
example 1:
a production process of isostatic pressing special graphite comprises the following steps:
(1) crushing and primary grinding: the calcined coke, the asphalt coke and the modified asphalt are firstly and primarily crushed to below 10mm by a crusher respectively, and then are respectively crushed to the particle size of 10-20 microns by a pulverizer respectively.
(2) Kneading and cooling: and (2) mixing the crushed calcined coke, the crushed asphalt coke and the crushed modified asphalt according to the weight ratio of 30: 37: 33, heating the paste by using heat conducting oil at the temperature of 200 ℃ for 4 hours, and feeding the paste into a cooling machine for stirring and cooling.
(3) Secondary crushing, secondary grinding and screening: and (3) putting the cooled paste into a crusher to be coarsely crushed to the granularity of less than 10mm, crushing the paste to the granularity of 15-30 microns by using a flour mill, and sieving the crushed material by using a 60-mesh sieving machine.
(4) Isostatic pressing: loading the screened materials into a rubber die sleeve, and hoisting the rubber die sleeve into an isostatic press after vibration and vacuum pumping; setting the pressure parameters of the isostatic pressing machine as follows: the highest pressure is 130MPa, the pressure maintaining time of the highest pressure is 30 minutes, and the pressure relief time is 10 minutes.
(5) Primary roasting: and (3) putting the isostatic-pressing molded green body into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 600 hours at the highest temperature of 1000 ℃, cooling to a proper temperature, and discharging.
(6) Dipping: cleaning the surface of a product after being roasted and discharged from a furnace, hanging the product into a preheating furnace, wherein the temperature of the preheating furnace is 360 ℃, the preheating time is 5 hours, the preheated product is timely hung into a dipping tank, covering a tank cover, firstly vacuumizing to-0.098 MPa, keeping the vacuum for 30 minutes, injecting asphalt into the tank, pressurizing to 2.5MPa, keeping the pressure for 3 hours, returning the asphalt, cooling, then opening the cover, and hanging the product out.
(7) Secondary roasting: and (3) loading the dipped product into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 300 hours at the highest temperature of 900 ℃, cooling to a proper temperature, and discharging.
(8) Graphitization: cleaning the side wall, the end wall and the furnace bottom of the furnace, and laying new furnace bottom materials again, wherein the height of the furnace bottom material layer is ensured to ensure that the center of the cross section of the furnace core is symmetrical to the center of the conductive electrode group of the end wall of the furnace end, and the furnace bottom is allowed to sink after being electrified, so that the height of the laid furnace bottom material layer is allowed to be higher by 50 mm; putting products to be graphitized into a graphitizing furnace, wherein each group of products is separated by a resistance material, heat insulation materials are filled at two sides of the graphitizing furnace, and a layer of heat insulation material with the thickness of more than 750mm is covered on the top of the furnace; and (4) electrifying for 300 hours, wherein the highest temperature is higher than 2500 ℃, and discharging the cooled special graphite to obtain the isostatic pressing special graphite.
Example 2:
a production process of isostatic pressing special graphite comprises the following steps:
(1) crushing and primary grinding: the calcined coke, the asphalt coke and the modified asphalt are firstly and primarily crushed to below 10mm by a crusher respectively, and then are respectively crushed to the particle size of 10-20 microns by a pulverizer respectively.
(2) Kneading and cooling: and (2) mixing the crushed calcined coke, the crushed asphalt coke and the crushed modified asphalt according to the weight ratio of 30: 35: 35, heating the paste by using heat conducting oil at the temperature of 200 ℃ for 5 hours, and feeding the paste into a cooling machine for stirring and cooling.
(3) Secondary crushing, secondary grinding and screening: and (3) putting the cooled paste into a crusher to be coarsely crushed to the granularity of less than 10mm, crushing the paste to the granularity of 15-30 microns by using a flour mill, and sieving the crushed material by using a 60-mesh sieving machine.
(4) Isostatic pressing: loading the screened materials into a rubber die sleeve, and hoisting the rubber die sleeve into an isostatic press after vibration and vacuum pumping; setting the pressure parameters of the isostatic pressing machine as follows: the highest pressure is 130MPa, the pressure maintaining time of the highest pressure is 60 minutes, and the pressure relief time is 10 minutes.
(5) Primary roasting: and (3) putting the isostatic-pressing molded green body into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 600 hours at the highest temperature of 1050 ℃, cooling to a proper temperature, and discharging.
(6) Dipping: cleaning the surface of a product after being roasted and discharged from a furnace, hanging the product into a preheating furnace, wherein the temperature of the preheating furnace is 360 ℃, the preheating time is 5 hours, hanging the preheated product into a dipping tank in time, covering a tank cover, firstly vacuumizing to-0.098 MPa, keeping the vacuum for 60 minutes, injecting asphalt into the tank, pressurizing to 3.0MPa, keeping the pressure for 2 hours, returning the asphalt, cooling, then opening the cover, and hanging the product out.
(7) Secondary roasting: and (3) loading the dipped product into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 300 hours at the highest temperature of 900 ℃, cooling to a proper temperature, and discharging.
(8) Graphitization: cleaning the side wall, the end wall and the furnace bottom of the furnace, and laying new furnace bottom materials again, wherein the height of the furnace bottom material layer is ensured to ensure that the center of the cross section of the furnace core is symmetrical to the center of the conductive electrode group of the end wall of the furnace end, and the furnace bottom is allowed to sink after being electrified, so that the height of the laid furnace bottom material layer is allowed to be higher by 50 mm; putting products to be graphitized into a graphitizing furnace, wherein each group of products is separated by a resistance material, heat insulation materials are filled at two sides of the graphitizing furnace, and a layer of heat insulation material with the thickness of more than 750mm is covered on the top of the furnace; and (4) electrifying for 250 hours, wherein the highest temperature is higher than 2500 ℃, and discharging the cooled special graphite to obtain the isostatic pressing special graphite.
Example 3:
a production process of isostatic pressing special graphite comprises the following steps:
(1) crushing and primary grinding: the calcined coke, the asphalt coke and the modified asphalt are firstly and primarily crushed to below 10mm by a crusher respectively, and then are respectively crushed to the particle size of 10-20 microns by a pulverizer respectively.
(2) Kneading and cooling: and (2) mixing the crushed calcined coke, the crushed asphalt coke and the crushed modified asphalt according to the weight ratio of 30: 38: 32 is added into a kneading machine, the kneading machine is heated by heat conducting oil, the temperature of the heat conducting oil is 200 ℃, and after 5 hours of kneading, the paste is put into a cooling machine for stirring and cooling.
(3) Secondary crushing, secondary grinding and screening: and putting the cooled paste into a crusher to be coarsely crushed to the granularity of less than 10mm, crushing the paste to the granularity of 15-30 microns by using a flour mill, and screening the crushed material by using a 80-mesh screening machine.
(4) Isostatic pressing: loading the screened materials into a rubber die sleeve, and hoisting the rubber die sleeve into an isostatic press after vibration and vacuum pumping; setting the pressure parameters of the isostatic pressing machine as follows: the maximum pressure is 150MPa, the pressure maintaining time is 60 minutes, and the pressure relief time is 10 minutes.
(5) Primary roasting: and (3) putting the isostatic-pressed green body into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 500 hours at the highest temperature of 900 ℃, cooling to a proper temperature, and discharging.
(6) Dipping: cleaning the surface of a product after being roasted and discharged from a furnace, hanging the product into a preheating furnace, wherein the temperature of the preheating furnace is 360 ℃, the preheating time is 5 hours, hanging the preheated product into a dipping tank in time, covering a tank cover, firstly vacuumizing to-0.098 MPa, keeping the vacuum for 30 minutes, injecting asphalt into the tank, pressurizing to 3.0MPa, keeping the pressure for 3 hours, returning the asphalt, cooling, then opening the cover, and hanging the product out.
(7) Secondary roasting: and (3) loading the dipped product into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 300 hours at the highest temperature of 800 ℃, cooling to a proper temperature, and discharging.
(8) Graphitization: cleaning the side wall, the end wall and the furnace bottom of the furnace, and laying new furnace bottom materials again, wherein the height of the furnace bottom material layer is ensured to ensure that the center of the cross section of the furnace core is symmetrical to the center of the conductive electrode group of the end wall of the furnace end, and the furnace bottom is allowed to sink after being electrified, so that the height of the laid furnace bottom material layer is allowed to be higher by 50 mm; putting products to be graphitized into a graphitizing furnace, wherein each group of products is separated by a resistance material, heat insulation materials are filled at two sides of the graphitizing furnace, and a layer of heat insulation material with the thickness of more than 750mm is covered on the top of the furnace; and (4) electrifying for 300 hours, wherein the highest temperature is higher than 2500 ℃, and discharging the cooled special graphite to obtain the isostatic pressing special graphite.
Example 4:
a production process of isostatic pressing special graphite comprises the following steps:
(1) crushing and primary grinding: the calcined coke, the asphalt coke and the modified asphalt are firstly and primarily crushed to below 10mm by a crusher respectively, and then are respectively crushed to the particle size of 10-20 microns by a pulverizer respectively.
(2) Kneading and cooling: crushing calcined coke, asphalt coke and modified asphalt in a weight ratio of 32: 37: 31, heating the paste by using heat conducting oil at the temperature of 200 ℃ for 5 hours, and feeding the paste into a cooling machine for stirring and cooling.
(3) Secondary crushing, secondary grinding and screening: and putting the cooled paste into a crusher to be coarsely crushed to the granularity of less than 10mm, crushing the paste to the granularity of 15-30 microns by using a flour mill, and screening the crushed material by using a screening machine of 70 meshes.
(4) Isostatic pressing: loading the screened materials into a rubber die sleeve, and hoisting the rubber die sleeve into an isostatic press after vibration and vacuum pumping; setting the pressure parameters of the isostatic pressing machine as follows: the highest pressure is 100MPa, the pressure maintaining time at the highest pressure is 90 minutes, and the pressure relief time is 15 minutes.
(5) Primary roasting: and (3) putting the isostatic-pressed green body into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 600 hours at the highest temperature of 950 ℃, cooling to a proper temperature, and discharging.
(6) Dipping: cleaning the surface of a product after being roasted and discharged from a furnace, hanging the product into a preheating furnace, wherein the temperature of the preheating furnace is 360 ℃, the preheating time is 3 hours, the preheated product is timely hung into a dipping tank, covering a tank cover, firstly vacuumizing to-0.098 MPa, keeping the vacuum for 80 minutes, injecting asphalt into the tank, pressurizing to 3.5MPa, keeping the pressure for 2 hours, returning the asphalt, cooling, then opening the cover, and hanging the product out.
(7) Secondary roasting: and (3) loading the dipped product into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 200 hours at the highest temperature of 900 ℃, cooling to a proper temperature, and discharging.
(8) Graphitization: cleaning the side wall, the end wall and the furnace bottom of the furnace, and laying new furnace bottom materials again, wherein the height of the furnace bottom material layer is ensured to ensure that the center of the cross section of the furnace core is symmetrical to the center of the conductive electrode group of the end wall of the furnace end, and the furnace bottom is allowed to sink after being electrified, so that the height of the laid furnace bottom material layer is allowed to be higher by 50 mm; putting products to be graphitized into a graphitizing furnace, wherein each group of products is separated by a resistance material, heat insulation materials are filled at two sides of the graphitizing furnace, and a layer of heat insulation material with the thickness of more than 750mm is covered on the top of the furnace; and (4) electrifying for 300 hours, wherein the highest temperature is higher than 2500 ℃, and discharging the cooled special graphite to obtain the isostatic pressing special graphite.
Example 5:
a production process of isostatic pressing special graphite comprises the following steps:
(1) crushing and primary grinding: the calcined coke, the asphalt coke and the modified asphalt are firstly and primarily crushed to below 10mm by a crusher respectively, and then are respectively crushed to the particle size of 10-20 microns by a pulverizer respectively.
(2) Kneading and cooling: and (2) mixing the crushed calcined coke, the crushed asphalt coke and the crushed modified asphalt according to the weight ratio of 35: 32: 33, heating the paste by using heat conducting oil at the temperature of 200 ℃ for 4 hours, and feeding the paste into a cooling machine for stirring and cooling.
(3) Secondary crushing, secondary grinding and screening: and (3) putting the cooled paste into a crusher to be coarsely crushed to the granularity of less than 10mm, crushing the paste to the granularity of 15-30 microns by using a flour mill, and sieving the crushed material by using a 60-mesh sieving machine.
(4) Isostatic pressing: loading the screened materials into a rubber die sleeve, and hoisting the rubber die sleeve into an isostatic press after vibration and vacuum pumping; setting the pressure parameters of the isostatic pressing machine as follows: the highest pressure is 150MPa, the pressure maintaining time of the highest pressure is 60 minutes, and the pressure relief time is 12 minutes.
(5) Primary roasting: and (3) putting the isostatic-pressing molded green body into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 800 hours at the highest temperature of 1050 ℃, cooling to a proper temperature, and discharging.
(6) Dipping: cleaning the surface of a product after being roasted and discharged from a furnace, hanging the product into a preheating furnace, wherein the temperature of the preheating furnace is 330 ℃, the preheating time is 6 hours, the preheated product is timely hung into a dipping tank, covering a tank cover, firstly vacuumizing to-0.098 MPa, keeping the vacuum for 60 minutes, injecting asphalt into the tank, pressurizing to 3.5MPa, keeping the pressure for 2.5 hours, returning the asphalt, cooling, then opening the cover, and hanging the product.
(7) Secondary roasting: and (3) loading the dipped product into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 300 hours at the highest temperature of 850 ℃, cooling to a proper temperature, and discharging.
(8) Graphitization: cleaning the side wall, the end wall and the furnace bottom of the furnace, and laying new furnace bottom materials again, wherein the height of the furnace bottom material layer is ensured to ensure that the center of the cross section of the furnace core is symmetrical to the center of the conductive electrode group of the end wall of the furnace end, and the furnace bottom is allowed to sink after being electrified, so that the height of the laid furnace bottom material layer is allowed to be higher by 45 mm; putting products to be graphitized into a graphitizing furnace, wherein each group of products is separated by a resistance material, heat insulation materials are filled at two sides of the graphitizing furnace, and a layer of heat insulation material with the thickness of more than 750mm is covered on the top of the furnace; and (4) electrifying for 300 hours, wherein the highest temperature is higher than 2500 ℃, and discharging the cooled special graphite to obtain the isostatic pressing special graphite.
Example 6:
a production process of isostatic pressing special graphite comprises the following steps:
(1) crushing and primary grinding: the calcined coke, the asphalt coke and the modified asphalt are firstly and primarily crushed to below 10mm by a crusher respectively, and then are respectively crushed to the particle size of 10-20 microns by a pulverizer respectively.
(2) Kneading and cooling: crushing calcined coke, asphalt coke and modified asphalt in a weight ratio of 37: 28: 35, heating the paste by using heat conducting oil at the temperature of 200 ℃ for 4 hours, and feeding the paste into a cooling machine for stirring and cooling.
(3) Secondary crushing, secondary grinding and screening: and (3) putting the cooled paste into a crusher to be coarsely crushed to the granularity of less than 10mm, crushing the paste to the granularity of 15-30 microns by using a flour mill, and sieving the crushed material by using a 90-mesh sieving machine.
(4) Isostatic pressing: loading the screened materials into a rubber die sleeve, and hoisting the rubber die sleeve into an isostatic press after vibration and vacuum pumping; setting the pressure parameters of the isostatic pressing machine as follows: the highest pressure is 130MPa, the pressure maintaining time of the highest pressure is 30 minutes, and the pressure relief time is 18 minutes.
(5) Primary roasting: and (3) putting the isostatic-pressing molded green body into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 900 hours at the highest temperature of 1100 ℃, cooling to a proper temperature, and discharging.
(6) Dipping: cleaning the surface of a product after being roasted and discharged from a furnace, hanging the product into a preheating furnace, wherein the temperature of the preheating furnace is 330 ℃, the preheating time is 6 hours, the preheated product is timely hung into a dipping tank, covering a tank cover, firstly vacuumizing to-0.098 MPa, keeping the vacuum for 60 minutes, injecting asphalt into the tank, pressurizing to 3.5MPa, keeping the pressure for 2 hours, returning the asphalt, cooling, then opening the cover, and hanging the product out.
(7) Secondary roasting: and (3) loading the dipped product into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 200 hours at the highest temperature of 800 ℃, cooling to a proper temperature, and discharging.
(8) Graphitization: cleaning the side wall, the end wall and the furnace bottom of the furnace, and laying new furnace bottom materials again, wherein the height of the furnace bottom material layer is ensured to ensure that the center of the cross section of the furnace core is symmetrical to the center of the conductive electrode group of the end wall of the furnace end, and the furnace bottom is allowed to sink after being electrified, so that the height of the laid furnace bottom material layer is allowed to be higher by 45 mm; putting products to be graphitized into a graphitizing furnace, wherein each group of products is separated by a resistance material, heat insulation materials are filled at two sides of the graphitizing furnace, and a layer of heat insulation material with the thickness of more than 750mm is covered on the top of the furnace; and (4) electrifying for 380 hours, cooling at the maximum temperature of more than 2500 ℃, and discharging to obtain the isostatic pressing special graphite.
The performance of the isostatic graphite products obtained from the respective examples of the present invention was tested under the same experimental conditions. The specific performance parameters of the isostatic graphite products obtained by the test are shown in the following table:
according to the experimental results, it can be found that: the isostatic pressing graphite prepared in the embodiments 1-6 of the invention has excellent performance, wherein the production process adopted in the embodiment 3 is a relatively better technical scheme of the invention, and the obtained isostatic pressing graphite has the best performance.
The design of the invention is characterized in that: the modified asphalt powder is used as a binder, the calcined coke powder, the asphalt coke powder and the modified asphalt powder are simultaneously added into a kneading machine for stirring and kneading in the kneading process, the asphalt is gradually melted along with the rise of the temperature and uniformly permeates into the calcined coke and the asphalt coke powder, and part of the asphalt is uniformly coated on the surfaces of the calcined coke and the asphalt coke powder, so that the independent asphalt melting step is omitted, the distribution of the asphalt is more uniform, and the finished product rate and the physical and chemical performance index of the product are improved.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the technical scope of the present invention, so that any minor modifications, equivalent changes and modifications made to the above embodiment according to the technical spirit of the present invention are within the technical scope of the present invention.
Claims (3)
1. A production process of isostatic pressing special graphite is characterized in that: the method comprises the following steps:
(1) crushing and primary grinding: firstly, primarily crushing calcined coke, pitch coke and modified pitch to below 10mm by using a crusher respectively, and then crushing the crushed coke, the pitch coke and the modified pitch to the particle size of 10-20 microns by using a pulverizer respectively;
(2) kneading and cooling: the crushed calcined coke, the asphalt coke and the modified asphalt are mixed according to the weight ratio (20-40): (20-40): (25-50), heating the paste by using heat conducting oil for the kneading machine, wherein the temperature of the heat conducting oil is 180-260 ℃, and stirring and cooling the paste in a cooling machine after 1-5 hours of kneading;
(3) secondary crushing, secondary grinding and screening: putting the cooled paste into a crusher to be coarsely crushed to the granularity of below 10mm, crushing the paste to the granularity of 15-30 microns by using a pulverizer, and sieving the crushed material by using a sieving machine of 60-100 meshes;
(4) isostatic pressing: loading the screened materials into a rubber die sleeve, and hoisting the rubber die sleeve into an isostatic press after vibration and vacuum pumping; setting the pressure parameters of the isostatic pressing machine as follows: the maximum pressure is 60-200 MPa, the pressure maintaining time is 10-120 minutes, and the pressure relief time is 1-20 minutes;
(5) primary roasting: putting the green body subjected to isostatic pressing into a roasting furnace, filling the periphery of the green body with quartz sand, roasting for 200-1000 hours at the highest roasting temperature of 800-1250 ℃, cooling to a proper temperature, and discharging;
(6) dipping: cleaning the surface of a product after roasting and discharging, hanging the product into a preheating furnace, enabling the temperature of the preheating furnace to be 260-400 ℃, enabling the preheating time to be 2-10 hours, timely hanging the preheated product into a dipping tank, covering a tank cover, firstly vacuumizing to-0.098 MPa, keeping the vacuum for 10-90 minutes, injecting asphalt into the tank, pressurizing to 1.5-5.0 MPa, keeping the pressure for 1-5 hours, returning the asphalt, cooling, then opening the cover, and hanging the product out;
(7) secondary roasting: placing the dipped product into a roasting furnace, filling quartz sand around the green body, roasting for 100-500 hours at the highest temperature of 800-1150 ℃, cooling to a proper temperature, and discharging;
(8) and graphitizing to obtain the isostatic pressing special graphite.
2. The production process of the isostatic special graphite as claimed in claim 1, wherein: the calcined coke, the asphalt coke and the modified asphalt in the step (2) are mixed according to the weight ratio of 30: 38: 32.
3. the production process of the isostatic special graphite as claimed in claim 1, wherein: in the step (8), the graphitization specifically comprises: cleaning the side wall, the end wall and the furnace bottom of the furnace, and laying new furnace bottom materials again, wherein the height of the furnace bottom material layer is ensured to ensure that the center of the cross section of the furnace core is symmetrical to the center of the conductive electrode group of the end wall of the furnace end, and the furnace bottom is allowed to sink after being electrified, so that the height of the laid furnace bottom material layer is allowed to be 30-50 mm higher; putting products to be graphitized into a graphitizing furnace, wherein each group of products is separated by a resistance material, heat insulation materials are filled at two sides of the graphitizing furnace, and a layer of heat insulation material with the thickness of more than 750mm is covered on the top of the furnace; and (4) the power transmission time is 200-400 hours, the highest temperature is more than 2500 ℃, and the steel plate is discharged after being cooled.
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