CN115353391B - Method for preparing special graphite material by isostatic pressing of graphite waste in short process - Google Patents
Method for preparing special graphite material by isostatic pressing of graphite waste in short process Download PDFInfo
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Abstract
The invention discloses a method for preparing special graphite materials by isostatic pressing of graphite waste in a short process, which comprises the following steps: pretreating graphite waste powder to obtain graphite powder with D50 of 3-10 mu m; adding graphite powder, a sulfur-containing cross-linking agent 1 and oleic acid 1 into a kneading pot, removing water, melting a binder 1, adding into the kneading pot for kneading, rolling, crushing, grinding, pressing and forming, then carrying out low-temperature carbonization treatment under pressure, crushing, grinding and sieving to obtain low-temperature carbonized powder A; adding the forged coke powder, the sulfur-containing cross-linking agent 2 and the oleic acid 2 into a kneading pot, removing water, heating, melting the binder 2, adding into the kneading pot for kneading, and obtaining low-temperature carbonized powder B according to the method; finally preparing special graphite material by adopting low-temperature carbonized powder A, low-temperature carbonized powder B, solvent pretreated raw coke powder and high-carbon modified asphalt. The method can effectively improve the added value and the usage amount of the graphite waste powder, and the prepared graphite material has excellent flexural strength and compressive strength.
Description
Technical Field
The invention belongs to the technical field of graphite materials, and particularly relates to a method for preparing special graphite materials by using isostatic pressing graphite waste in a short process.
Background
Isostatic graphite is a novel material developed internationally for nearly 60 years. Isostatic graphite has been widely used in the fields of semiconductors, photovoltaics, aerospace, nuclear power, new energy automobiles and the like because of its excellent mechanical properties, corrosion resistance, self-lubricating properties and thermal conductivity. Specifically, it is mainly used for a graphite crucible for single crystal silicon production; rocket nozzles and sealing elements for aerospace; neutron moderator and reflector of nuclear reactor; an electrode during the electric discharge machining; new energy automobile electronic water pump bearings, etc.
However, in the production of the graphite parts using isostatic pressure graphite, a large amount of milling powder, fragments and scraps (collectively referred to as graphite waste powder) are produced, which is about 30-50 wt.%. Moreover, the graphite waste powder is difficult to prepare high-performance graphite materials by a traditional method due to the characteristics of high graphitization degree, low strength, low activity of carbon atoms at the edge, few hetero atoms, smooth surface and the like. Therefore, under the large background of the 'double carbon' strategic target, the application of the graphite waste powder in different fields is actively explored, and the method has practical significance for environmental protection and full utilization of non-renewable resources.
At present, an isostatic pressing graphite processing enterprise purchases a graphite blank body from an isostatic pressing graphite manufacturer at a high price, and graphite waste powder generated in the processing process is only sold to related manufacturers such as carburant, anode paste, carbon brush, carbon brick, graphite crucible and the like at a low price. For this reason, the manufacturer who purchases the graphite waste powder generally only uses the graphite waste powder as a filler to add a small amount (about 5-10 wt.% of aggregate), so as to properly reduce the cost, improve the preparation manufacturability and the heat conductivity of the product, and the like.
Therefore, how to further improve the added value and the usage amount of the graphite waste powder is still the research focus of the related carbon graphite enterprises.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide a method for preparing special graphite materials by isostatic pressing of graphite waste in a short process, the method can effectively improve the added value and the use amount of graphite waste powder, and the prepared graphite materials have excellent properties such as flexural strength, compressive strength and the like.
The technical scheme of the invention is realized as follows:
the method for preparing the special graphite material by using the isostatic pressing graphite waste in a short process comprises the following steps:
s1: pretreating graphite waste powder to obtain graphite powder with D50 of 3-10 mu m, wherein the graphite waste powder is leftover materials, fragments and milling powder of isostatic pressing graphite;
s2: preparing 30-40 parts of a binder, 50-70 parts of graphite powder obtained in S1, 1-5 parts of a sulfur-containing cross-linking agent and 1-5 parts of oleic acid;
s3: putting graphite powder, a sulfur-containing cross-linking agent and oleic acid in the S2 into a kneading pot for premixing, heating to 155-185 ℃ after removing water, adding the binder in the S2 into the kneading pot for kneading after melting, rolling, crushing, grinding, compacting, carbonizing at low temperature under pressure, crushing, grinding and sieving to obtain low-temperature carbonized powder A after finishing kneading;
s4: 25-30 parts of a bonding agent, 50-80 parts of calcined coke powder, 1-5 parts of a sulfur-containing cross-linking agent and 1-5 parts of oleic acid are prepared;
s5: adding the forged coke powder in the step S4, a sulfur-containing cross-linking agent and oleic acid into a kneading pot, removing water, heating to 155-185 ℃, adding the binder in the step S4 into the kneading pot for kneading after melting, rolling, crushing, grinding, pressing and forming after kneading, then carrying out low-temperature carbonization treatment under pressure, crushing, grinding and sieving to obtain low-temperature carbonized powder B;
s6: accurately weighing 10-20 parts of high-carbon-residue reformed asphalt, 60-70 parts of low-temperature carbonized powder A in S3, 10-20 parts of low-temperature carbonized powder B in S5, and 1-5 parts of solvent pre-treated raw coke powder;
s7: putting the low-temperature carbonized powder A, the low-temperature carbonized powder B and the solvent pretreated raw coke powder in the S6 into a kneading pot, heating to 170-200 ℃ after removing water, melting the high-carbon modified asphalt in the S6, adding into the kneading pot for kneading, and rolling, crushing and grinding to obtain pressed powder after kneading;
s8: pressing the pressed powder obtained in the step S7 into a powder with the density of 1.1-1.3 g/cm 3 Placing the block in a vacuum packaging bag for a period of time, and then placing the block in a cold isostatic pressing device for 1-3 times to obtain the block with the density of 1.63-1.66 g/cm 3 Is a green body block of (c);
s9: placing the green body block in a stainless steel crucible, burying the green body block with a burying material, placing in a roasting furnace, applying pressure, introducing nitrogen or argon in the pressure roasting process, roasting for 2-6 hours at 800-1200 ℃, performing program control cooling to 200-300 ℃, and naturally cooling to room temperature to obtain the ceramic green body with the density of 1.68-1.74 g/cm 3 Is a fired block of (a);
s10: placing the baked block in a vacuum graphitization furnace for atmosphere protection, treating for 1-4 hours at 2400-2800 ℃, performing program control, cooling to 200-300 ℃, and naturally cooling to room temperature to obtain the product with the volume density of 1.81-1.85 g/cm 3 Is a special graphite material.
Further, in S1, firstly, removing metal impurities in graphite waste powder by adopting magnetic separation equipment, sieving and classifying, then, carrying out primary grinding on the graphite waste powder by adopting a 3R Raymond mill, and then, carrying out fine grinding by adopting an airflow mill, thus obtaining the graphite powder with D50 of 3-10 mu m.
Further, the binder is one or more of low-temperature asphalt, modified asphalt, medium-temperature asphalt or high-temperature asphalt with low quinoline insoluble content, anthracene oil, coal tar and ethylene tar.
Further, the sulfur-containing crosslinking agent is one or more of dodecyl mercaptan, tetramethyl thiuram disulfide, dithiodimorpholine, alkylphenol methylol polysulfide, alkylphenol sulfide or alkylphenol polysulfide.
Further, the specific steps of S3 are as follows:
s3.1: putting graphite powder, a sulfur-containing cross-linking agent and oleic acid into a kneading pot, mixing for 1-2 hours at 110-120 ℃, removing water, and rotating the kneading pot at the rotating speed of 10-50 r/min in a forward direction;
s3.2: after the water removal is finished, heating to 155-185 ℃, adding the melted binder in the S2 into a kneading pot, kneading for 1-2 hours to obtain paste, wherein the rotating speed of the kneading pot is 10-50 r/min, forward rotation and reverse rotation are alternately performed, and intermittent opening and closing cover mixing is performed;
s3.3: after the kneading is finished, rapidly transferring the paste to a material hopper of a sheet rolling machine, rolling the sheet for 2-3 times, wherein the thickness of the rolled sheet is 1-2 mm, the temperature of the rolled sheet corresponds to the kneading temperature, and the rotating speed is 10-30 r/min;
s3.4: after finishing cooling the rolled sheet to room temperature, placing for 2-10 hours, crushing and grinding, sieving with a 100-320 mesh sieve, and placing for 2-10 hours to obtain pressed powder;
s3.5: and (3) performing compression molding under 10-20 MPa for 2-10 h, placing the obtained pressed powder in an atmosphere resistance furnace, performing pressure coking treatment at 500-650 ℃ for 2-6 h through program temperature control, cooling to room temperature along with the furnace, crushing and grinding the coked block, and sieving with a 100-200-mesh sieve to obtain the low-temperature carbonized powder A.
Further, the forged coke powder in the step S4 is one or two of calcined pitch coke, petroleum coke and needle coke, and the D50 of the forged coke powder is 3-10 mu m.
Further, the specific steps of S5 are as follows:
s5.1: adding the forged coke powder, the sulfur-containing cross-linking agent and the oleic acid into a kneading pot, mixing for 1-2 hours at 110-120 ℃, removing water, and rotating the kneading pot at the rotating speed of 10-50 r/min in a forward direction;
s5.2: after the water is removed, heating to 155-185 ℃, adding the melted binder in the step S4 into a kneading pot, kneading for 1-2 hours to obtain paste, wherein the rotating speed of the kneading pot is 10-50 r/min, forward rotation and reverse rotation are alternately performed, and intermittent opening and closing cover mixing is performed;
s5.3: after the kneading is finished, rapidly transferring the paste to a material hopper of a sheet rolling machine, rolling the sheet for 2-3 times, wherein the thickness of the rolled sheet is 1-2 mm, the temperature of the rolled sheet corresponds to the kneading temperature, and the rotating speed is 10-30 r/min;
s5.4: after finishing cooling the rolled sheet to room temperature, placing for 2-10 hours, crushing and grinding, sieving with a 100-320 mesh sieve, and placing for 2-10 hours to obtain pressed powder;
s5.5: and (3) performing compression molding under 10-30 MPa for 2-10 h, placing the obtained pressed powder in an atmosphere resistance furnace, performing pressure coking treatment at 300-600 ℃ for 2-6 h through program temperature control, cooling to room temperature along with the furnace, crushing and grinding the coked block, and sieving with a 100-200-mesh sieve to obtain the low-temperature carbonized powder B.
Further, the solvent in S6 pretreats the raw coke powder to one or more of raw petroleum coke, raw pitch coke, raw needle coke, or raw mesophase carbon microspheres.
Further, the specific steps of S7 are:
s7.1: putting the low-temperature carbonized powder A, the low-temperature carbonized powder B and the solvent pretreated raw coke powder into a kneading pot, mixing for 1-2 hours at 110-120 ℃, removing water, and rotating the kneading pot at the rotating speed of 10-50 r/min in a forward direction;
s7.2: after the water removal is finished, heating to 240-300 ℃, melting the high-carbon residue modified asphalt in the step S6, adding the melted high-carbon residue modified asphalt into a kneading pot, kneading for 1-2 hours, wherein the rotating speed of the kneading pot is 10-50 r/min, and alternately carrying out forward rotation and reverse rotation, and intermittently opening and closing a cover for mixing;
s7.3: after the mixing and kneading are finished, rapidly transferring the mixture to a material hopper of a sheet rolling machine, rolling the sheet for 1-2 times, wherein the thickness of the rolled sheet is 1-4 mm, the temperature of the rolled sheet corresponds to the mixing and kneading temperature, the rotating speed is 10-30 r/min, performing program temperature control cooling after the rolling is finished, cooling to room temperature, placing for 2-10 h, crushing and grinding, sieving with a 100-320-mesh sieve, and placing for 2-10 h to obtain pressed powder.
Further, the specific steps of S8 are:
s8.1: pressing the pressed powder obtained in the step S7 under the pressure of 1-5 MPa to obtain the powder with the density of 1.1-1.3 g/cm 3 Placing the blocks in vacuum packaging bags for 2-10 h;
s8.2: placing the mixture in cold isostatic pressing equipment, and performing gradient pressure relief after pressing for 5-30 min under 50-100 MPa;
s8.3: after the pressure relief is completed, the mixture is placed for 2 to 10 hours, pressed for 5 to 30 minutes under 150 to 200 MPa, subjected to gradient pressure relief, taken out, peeled off and packaged, and placed for 2 to 10 hours, and the density of 1.63 to 1.66g/cm is obtained 3 Is a green body block of (c).
Compared with the prior art, the invention has the following beneficial effects:
1. the invention adopts graphite powder, sulfur-containing cross-linking agent, dispersant oleic acid, asphalt with low quinoline insoluble content, anthracene oil, coal tar, ethylene tar and other binders to prepare low-temperature carbonized powder A, and adopts the binders, calcined coke powder, sulfur-containing cross-linking agent and dispersant oleic acid to prepare low-temperature carbonized powder B.
In the preparation process, the dispersing agent can disperse the agglomerated graphite powder and the calcined coke powder, and the binder is good in fluidity and wettability, is easy to permeate into the pores of the graphite powder and the calcined coke powder, fills the pores and is coated on the surfaces of the graphite powder and the calcined coke powder. The sulfur-containing cross-linking agent is used as a cross-linking dehydrogenation agent, is favorable for condensation, aromatization and cyclization of aromatic hydrocarbon molecules in the binder, forms a cross-linking network to be coated on the surfaces of graphite powder and calcined coke powder, and increases the residual carbon content of coal tar pitch along with the precipitation of hydrogen sulfide gas, so that the true density of the graphite powder and the calcined coke powder is improved, and the porosity of the special graphite material is effectively reduced; and a carbonized layer and carbide with activity and self-sintering property are formed in the surface and pores of the graphite powder and the calcined coke powder after low-temperature coking.
Therefore, the low-temperature carbonized powder A and the low-temperature carbonized powder B have similar carbonized layers and carbides, so that the difference of thermal expansion coefficients of graphite powder and forged coke powder can be effectively reduced, cracking of the prepared green body block in the heat treatment process is avoided, and meanwhile, the forged coke powder has higher mechanical strength, so that the strength of special graphite materials is improved.
Meanwhile, the superfine raw coke powder pretreated by introducing a solvent with excellent self-sintering performance fills in an in-situ welding spot formed between the interfaces of the low-temperature carbonized powder A and the low-temperature carbonized powder B, so that the self-shrinkage performance and the homogeneity of the low-temperature carbonized powder A and the low-temperature carbonized powder B are improved; and the superfine solvent pretreatment raw coke powder can fill the pores formed by the low-temperature carbonized powder A and the low-temperature carbonized powder B, increase the green body pressing density, reduce the open porosity and further improve the strength of the special graphite material.
2. According to the invention, the special graphite material is prepared by taking the low-cost graphite waste powder as the main aggregate, so that the raw material cost for preparing the special graphite material is reduced, the added value and the use amount of the graphite waste powder are improved, the self-sintering performance and the self-adhesion performance are improved by introducing the sintering factor, the special graphite material prepared by one-time roasting graphitization is prepared, and the prepared special graphite material has excellent flexural strength and compressive strength.
3. The invention does not need to impregnate and bake for many times, after compression molding, graphitization can be directly carried out after one-time baking, thereby simplifying the process flow, shortening the production period, and greatly saving the labor cost, the energy cost, the time cost, the equipment investment and maintenance cost and the pollution treatment cost to the environment.
Drawings
FIG. 1-A transmission electron microscope image of graphite powder and low-temperature carbonized powder A in example 1.
FIG. 2 is a graph showing adsorption curves of graphite powder and low-temperature carbonized powder A in example 1.
FIG. 3 is a graph showing the micropore distribution of graphite powder and low-temperature carbonized powder A in example 1.
FIG. 4-macroscopic photograph of graphite powder and low temperature carbonized powder A dissolved in tetrahydrofuran in example 1.
FIG. 5 is a graph showing ESR curves of graphite powder and low-temperature carbonized powder A in example 1.
FIG. 6-A cross-sectional view of the special graphite material prepared in example 1, and a topography and a back dispersion of the polished surface.
FIG. 7-A cross-sectional view of the special graphite material prepared in example 2, and a topography and a back dispersion of the polished surface.
FIG. 8-sectional view of the special graphite material prepared in example 3, morphology and back scattering of polished surface.
Fig. 9-cross-sectional view of graphite material 1, topography and back-scattered view of polished surface.
Detailed Description
The invention is described in further detail below with reference to the drawings and the detailed description.
Example 1
S1: the isostatic pressure graphite waste powder is purchased from graphite processing factories at low price, metal impurities introduced by the powder are removed through magnetic separation equipment, the graphite waste powder is subjected to primary grinding through a 3R Raymond mill, and then the graphite powder with the D50 of about 6.0 mu m is prepared by adopting an airflow mill for later use.
S2: 18 parts of modified asphalt with low quinoline insoluble content, 14 parts of medium-temperature asphalt, 8 parts of coal tar, 55 parts of graphite powder obtained in S1, 2 parts of dodecyl mercaptan, 1 part of tetramethylthiuram disulfide and 2 parts of oleic acid are accurately weighed.
S3: adding graphite powder, dodecyl mercaptan, tetramethylthiuram disulfide and oleic acid into a kneading pot, mixing at 120 ℃ for 1 h, removing water, and rotating the kneading pot at a rotating speed of 30 r/min in a positive direction; after the water removal is finished, heating the powder to 185 ℃, introducing a modified asphalt, medium-temperature asphalt and coal tar mixed adhesive melted at a corresponding temperature (70-80 ℃ higher than the softening point of asphalt), kneading for 1 h, wherein the rotating speed of a kneading pot is 50r/min, and the forward rotation and the reverse rotation are alternately performed, and the cover is intermittently opened and closed for mixing. After the mixing and kneading are finished, the paste is quickly transferred to a material hopper of a tablet rolling machine, the tablet is rolled for 2 times, the thickness of the tablet is 2 mm, the tablet rolling temperature corresponds to the mixing and kneading temperature, the rotating speed is 10 r/min, the material is cooled after the tablet rolling is finished, the material is cooled to room temperature, crushed and milled after the material is placed at 10 h, and the powder is placed at 10 h after the material is screened by a 160-mesh sieve, so as to obtain the pressed powder. The prepared pressed powder is pressed and molded under 10 MPa through a compression molding process, and is placed in an atmosphere resistance furnace after being placed at 10 h, is subjected to coking treatment under pressure at 500 ℃ for 4 h through program temperature control, is cooled to room temperature along with the furnace, and is crushed and ground into powder, and is sieved by a 200-mesh sieve to prepare the low-temperature carbonized powder A.
S4: 30 parts of modified asphalt with low quinoline insoluble content, 65 parts of calcined asphalt coke, 2 parts of dodecyl mercaptan, 1 part of tetramethylthiuram disulfide and 2 parts of oleic acid are accurately weighed.
S5: putting the calcined pitch coke, dodecyl mercaptan, tetramethylthiuram disulfide and oleic acid in the S4 into a kneading pot, mixing at 120 ℃ for 1 h, removing water, and rotating the kneading pot at the speed of 30 r/min in a forward direction; after the water removal is finished, heating to 175 ℃, melting the modified asphalt and the medium-temperature asphalt in the step S4, adding the melted modified asphalt and the medium-temperature asphalt into a kneading pot, kneading for 1 h to obtain paste, wherein the rotating speed of the kneading pot is 50r/min, forward rotation and reverse rotation are alternately performed, and intermittent opening and closing cover mixing is performed; after the kneading is finished, rapidly transferring the paste to a material hopper of a sheet rolling machine, rolling the sheet for 2 times, wherein the thickness of the rolled sheet is 2 mm, the temperature of the rolled sheet corresponds to the kneading temperature, and the rotating speed is 10 r/min; after finishing cooling the rolled sheet to room temperature, placing 10 h, crushing and grinding, sieving with a 160-mesh sieve, and placing 10 h to obtain pressed powder; the preparation method comprises the steps of compression molding the prepared pressed powder under 10 MPa, placing the pressed powder in an atmosphere resistance furnace after placing the pressed powder in the 10 MPa for 10 h, carrying out pressure coking treatment at 550 ℃ for 2-6 hours by program temperature control, cooling the pressed powder along with the furnace to room temperature, crushing and grinding the coked block, and sieving the crushed powder with a 200-mesh sieve to obtain the low-temperature carbonized powder B.
S6: 15 parts of high-carbon-residue reformed asphalt, 70 parts of low-temperature carbonized powder A in S3, 10 parts of low-temperature carbonized powder B in S5 and 5 parts of solvent pretreated raw petroleum coke are accurately weighed.
S7: putting the low-temperature carbonized powder A in the step S6, the low-temperature carbonized powder B and the solvent pretreated raw petroleum coke into a kneading pot, mixing at 120 ℃ for 1 h, removing water, and rotating the kneading pot at the speed of 30 r/min in the forward direction; after the moisture removal is finished, the powder is heated to 185 ℃, then high-carbon residue modified high-temperature asphalt melted at a corresponding temperature is introduced, the mixing and kneading speed is 1 h, the rotating speed of a mixing and kneading pot is 50r/min, the forward rotation and the reverse rotation are alternately carried out, and the intermittent opening and closing covers are mixed. After the mixing and kneading are finished, the paste is quickly transferred to a material hopper of a tablet rolling machine, the tablet is rolled for 2 times, the thickness of the tablet is 2 mm, the temperature of the tablet corresponds to the mixing and kneading temperature, the rotating speed is 20 r/min, the program temperature control material cooling is carried out after the tablet rolling is finished, after the temperature of the material is reduced to the room temperature, the material is crushed and ground after being placed at 10 h, and the material is placed at 10 h after being screened by a 160-mesh sieve, so as to obtain the pressed powder.
S8: pressing the pressed powder of S7 under 1 MPa to obtain a density of 1.1-1.3 g/cm 3 Is vacuum packed into bags, and is placed 5 h; placing in cold isostatic pressing equipment, maintaining pressure at 200 MPa for 10 min, performing gradient pressure relief, taking out sample, peeling off the sealing bag, and standing for 10 h to obtain a product with density of 1.63-1.66 g/cm 3 Is a green body block of (c).
S9: placing the green body block prepared in the step S8 into a stainless steel crucible, filling with a filling material, introducing nitrogen/argon, roasting at 1050 ℃ for 4 h, cooling to 300 ℃ by program control, and naturally cooling to room temperature to obtain the green body block with the density of 1.68-1.74 g/cm 3 Is a fired block of (a). Placing the baked block in a vacuum graphitization furnace for atmosphere protection, treating at 2500 ℃ for 1 h, reducing the temperature to 200 ℃ by program control, and naturally cooling to room temperature to obtain the bulk density of 1.83 g/cm 3 Is a special graphite material.
1. The transmission electron microscope image, the adsorption curve graph, the micropore distribution curve graph, the macroscopic photograph of tetrahydrofuran-soluble graphite powder obtained by pretreatment and the prepared low-temperature carbonized powder A in the embodiment and the ESR curve graph are respectively shown in fig. 1, fig. 2, fig. 3, fig. 4 and fig. 5.
Fig. 1 (a) shows graphite powder, fig. 1 (b) shows low-temperature carbonized powder a, and fig. 1 shows that the active layer is successfully constructed on the surface of graphite powder. As can be seen from FIG. 2, the specific surface areas of the graphite powder and the low-temperature carbonized powder A are 14.445 m, respectively 2 /g and 4.077 m 2 As can be seen from fig. 3, the pore volume of the low temperature carbonized powder a is significantly lower than that of the graphite powder, indicating that the micropores of the graphite powder are filled with the modified asphalt having a low quinoline insoluble content and the medium temperature asphalt, thereby forming an active layer in the pores of the graphite powder and increasing the true density of the graphite powder. Active layer filled in graphite powder pores and coated on stoneThe active layer on the surface of the powdered ink can exert the 'needle-punching effect' to construct a firmer structure.
Fig. 4 (a) shows a low-temperature carbonized powder a, and fig. 4 (b) shows graphite powder, and as can be seen from fig. 4, the graphite powder has no color change in tetrahydrofuran, but the low-temperature carbonized powder a turns brown yellow in tetrahydrofuran, indicating that the low-temperature carbonized powder a has an active material such as aliphatic and aromatic compounds soluble in tetrahydrofuran. Further, as can be seen from fig. 5, the low-temperature carbonized powder a has a far higher radical content than the graphite powder, and the higher the radical content, the stronger the strength, indicating that the low-temperature carbonized powder a has higher activity and strength than the graphite powder.
2. The cross-sectional view of the special graphite material prepared in this embodiment and the morphology and back scattering of the polished surface are shown in fig. 6, wherein fig. 6 (a) is a cross-sectional view, and the left and right views of fig. 6 (b) are the morphology and back scattering of the polished surface, respectively, and as seen in fig. 6 (a), the port of the cross-section has a ductile pit, a compact structure and no through crack. As can be seen from fig. 6 (b), the special graphite material prepared in this embodiment has a compact structure, uniform pore distribution, and no macropores. The results show that the special graphite material prepared by the invention has compact structure and excellent performance.
Example 2
S1: the isostatic pressure graphite waste powder is purchased from graphite processing factories at low price, metal impurities introduced by the powder are removed through magnetic separation equipment, the graphite waste powder is subjected to primary grinding through a 3R Raymond mill, and then the graphite powder with the D50 of about 6.0 mu m is prepared by adopting an airflow mill for later use.
S2: 13 parts of modified asphalt with low quinoline insoluble content, 12 parts of coal tar, 5 parts of anthracene oil, 65 parts of graphite powder obtained in S1, 1 part of dodecyl mercaptan, 1 part of alkylphenol methylol polysulfide resin and 3 parts of oleic acid are accurately weighed.
S3: adding graphite powder, dodecyl mercaptan, polysulphide alkylphenol methylol resin and oleic acid into a kneading pot, mixing at 120 ℃ for 1 h, removing water, and rotating the kneading pot at a rotating speed of 30 r/min in a positive direction; after the water removal is finished, heating the powder to 175 ℃, introducing modified asphalt melted at a corresponding temperature (70-80 ℃ higher than the softening point of asphalt) and medium-temperature asphalt, kneading for 1 h, wherein the rotating speed of a kneading pot is 50r/min, and alternately carrying out forward rotation and reverse rotation, and intermittently opening and closing a cover for mixing. After the mixing and kneading are finished, the paste is quickly transferred to a material hopper of a tablet rolling machine, the tablet is rolled for 2 times, the thickness of the tablet is 2 mm, the tablet rolling temperature corresponds to the mixing and kneading temperature, the rotating speed is 10 r/min, the material is cooled after the tablet rolling is finished, the material is cooled to room temperature, crushed and milled after the material is placed at 10 h, and the powder is placed at 10 h after the material is screened by a 160-mesh sieve, so as to obtain the pressed powder. The prepared pressed powder is pressed and molded under 10 MPa through a compression molding process, and is placed in an atmosphere resistance furnace after being placed at 10 h, is subjected to coking treatment under pressure at 550 ℃ for 4 h through program temperature control, is cooled to room temperature along with the furnace, and is crushed and ground into powder, and is sieved by a 200-mesh sieve to prepare the low-temperature carbonized powder A.
S4: 10 parts of modified asphalt with low quinoline insoluble content, 10 parts of coal tar, 5 parts of ethylene tar, 70 parts of calcined asphalt coke, 1 part of dodecyl mercaptan, 2 parts of polysulphide alkylphenol methylol resin and 2 parts of oleic acid are accurately weighed.
S5: adding the calcined pitch coke, dodecyl mercaptan, the alkylphenol methylol polysulfide resin and the oleic acid in the S4 into a kneading pot, mixing at 120 ℃ for 2 h, removing water, and rotating the kneading pot at the speed of 50r/min in the forward direction; after the water removal is finished, heating to 185 ℃, adding the modified asphalt and the medium-temperature asphalt in the step S4 into a kneading pot for kneading for 1-2 hours to obtain paste, wherein the rotating speed of the kneading pot is 30 r/min, forward rotation and reverse rotation are alternately performed, and intermittent opening and closing cover mixing is performed; after the kneading is finished, rapidly transferring the paste to a material hopper of a sheet rolling machine, rolling the sheet for 2 times, wherein the thickness of the rolled sheet is 2 mm, the temperature of the rolled sheet corresponds to the kneading temperature, and the rotating speed is 20 r/min; after finishing cooling the rolled sheet to room temperature, placing 10 h, crushing and grinding, sieving with a 160-mesh sieve, and placing 10 h to obtain pressed powder; the prepared pressed powder is pressed and molded under 10 MPa through a compression molding process, and is placed in an atmosphere resistance furnace after being placed at 10 h, is subjected to coking treatment under pressure at 500 ℃ for 6 h through program temperature control, is cooled to room temperature along with the furnace, and is crushed and ground into powder, and is sieved by a 200-mesh sieve to prepare the low-temperature carbonized powder B.
S6: 17 parts of high-carbon-residue reformed asphalt, 65 parts of low-temperature carbonized powder A in S3, 15 parts of low-temperature carbonized powder B in S5 and 3 parts of solvent pretreated raw asphalt coke are accurately weighed.
S7: putting the low-temperature carbonized powder A in the step S6, the low-temperature carbonized powder B and the solvent pretreated raw asphalt coke into a kneading pot, mixing at 120 ℃ for 1 h, removing water, and rotating the kneading pot at the speed of 30 r/min in the forward direction; after the water removal is finished, the powder is heated to 200 ℃, then high-carbon residue modified high-temperature asphalt melted at a corresponding temperature is introduced, the mixing and kneading speed is 1 h, the rotating speed of a mixing and kneading pot is 50r/min, the forward rotation and the reverse rotation are alternately carried out, and the intermittent opening and closing covers are mixed. After the mixing and kneading are finished, the paste is quickly transferred to a material hopper of a tablet rolling machine, the tablet is rolled for 2 times, the thickness of the tablet is 2 mm, the temperature of the tablet corresponds to the mixing and kneading temperature, the rotating speed is 20 r/min, the program temperature control material cooling is carried out after the tablet rolling is finished, after the temperature of the material is reduced to the room temperature, the material is crushed and ground after being placed at 10 h, and the material is placed at 10 h after being screened by a 160-mesh sieve, so as to obtain the pressed powder.
S8: pressing the pressed powder of S7 under 1 MPa to obtain a density of 1.1-1.3 g/cm 3 Is vacuum packed into bags, and is placed 5 h; placing in cold isostatic pressing equipment, maintaining pressure at 200 MPa for 10 min, performing gradient pressure relief, taking out sample, peeling off the sealing bag, and standing for 10 h to obtain a product with density of 1.63-1.66 g/cm 3 Is a green body block of (c).
S9: placing the green body block prepared in the step S8 into a stainless steel crucible, filling with a filling material, introducing nitrogen/argon, roasting at 1050 ℃ for 4 h, cooling to 300 ℃ by program control, and naturally cooling to room temperature to obtain the green body block with the density of 1.68-1.74 g/cm 3 Is a fired block of (a). Placing the baked block in a vacuum graphitization furnace for atmosphere protection, treating at 2500 ℃ for 1 h, reducing the temperature to 200 ℃ by program control, and naturally cooling to room temperature to obtain the bulk density of 1.82 g/cm 3 Is a special graphite material.
The cross-sectional view of the special graphite material prepared in this embodiment and the morphology and back scattering of the polished surface are shown in fig. 7, wherein fig. 7 (a) is a cross-sectional view, and the left and right views of fig. 7 (b) are the morphology and back scattering of the polished surface, respectively, and as seen in fig. 7 (a), the port of the cross-section has a ductile pit, a compact structure and no through crack. As can be seen from fig. 7 (b), the special graphite material prepared in this embodiment has a compact structure, uniform pore distribution, and no macropores. The results show that the special graphite material prepared by the invention has compact structure and excellent performance.
Example 3
S1: the isostatic pressure graphite waste powder is purchased from graphite processing factories at low price, metal impurities introduced by the powder are removed through magnetic separation equipment, the graphite waste powder is subjected to primary grinding through a 3R Raymond mill, and then the graphite powder with the D50 of about 6.0 mu m is prepared by adopting an airflow mill for later use.
S2: 10 parts of coal tar, 21 parts of medium-temperature asphalt, 4 parts of anthracene oil, 61 parts of graphite powder obtained in S1, 2 parts of polysulphide alkylphenol methylol resin and 2 parts of oleic acid are accurately weighed.
S3: adding graphite powder, polysulphide alkylphenol methylol resin and oleic acid into a kneading pot, mixing at 120 ℃ for 1 h, removing water, and rotating the kneading pot at a rotating speed of 30 r/min in a positive direction; after the water removal is finished, heating the powder to 185 ℃, introducing modified asphalt melted at a corresponding temperature (70-80 ℃ higher than the softening point of asphalt) and medium-temperature asphalt to mix and knead for 1 h, wherein the rotating speed of a mixing kneading pot is 50r/min, forward rotation and reverse rotation are alternately performed, and intermittent opening and closing cover mixing is performed. After the mixing and kneading are finished, the paste is quickly transferred to a material hopper of a tablet rolling machine, the tablet is rolled for 2 times, the thickness of the tablet is 2 mm, the tablet rolling temperature corresponds to the mixing and kneading temperature, the rotating speed is 10 r/min, the material is cooled after the tablet rolling is finished, the material is cooled to room temperature, crushed and milled after the material is placed at 10 h, and the powder is placed at 10 h after the material is screened by a 160-mesh sieve, so as to obtain the pressed powder. The prepared pressed powder is pressed and molded under 10 MPa through a compression molding process, and is placed in an atmosphere resistance furnace after being placed at 10 h, is subjected to coking treatment under pressure at 600 ℃ for 4 h through program temperature control, is cooled to room temperature along with the furnace, and is crushed and ground into powder, and is sieved by a 200-mesh sieve to prepare the low-temperature carbonized powder A.
S4: 2 parts of coal tar, 12 parts of medium-temperature asphalt, 13 parts of modified asphalt with low quinoline insoluble content, 68 parts of calcined asphalt coke, 1 part of dodecyl mercaptan, 2 parts of alkylphenol sulfide and 2 parts of oleic acid are accurately weighed.
S5: putting the calcined asphalt coke, dodecyl mercaptan, alkylphenol sulfide and oleic acid in the S4 into a kneading pot, mixing for 1-2 hours at 110-120 ℃, and removing water, wherein the rotating speed of the kneading pot is 10-50 r/min, and rotating positively; after the water removal is finished, heating to 155 ℃, melting the modified asphalt and the medium-temperature asphalt in the step S4, adding the melted modified asphalt and the medium-temperature asphalt into a kneading pot, kneading for 2 h to obtain paste, wherein the rotating speed of the kneading pot is 10 r/min, forward rotation and reverse rotation are alternately performed, and intermittent opening and closing cover mixing is performed; after the kneading is finished, rapidly transferring the paste to a material hopper of a sheet rolling machine, rolling the sheet for 2 times, wherein the thickness of the rolled sheet is 2 mm, the temperature of the rolled sheet corresponds to the kneading temperature, and the rotating speed is 30 r/min; after finishing cooling the rolled sheet to room temperature, placing 2 h, crushing and grinding, sieving with a 160-mesh sieve, and placing 10 h to obtain pressed powder; the prepared pressed powder is pressed and molded under 30 MPa through a compression molding process, and is placed in an atmosphere resistance furnace after being placed at 10 h, is subjected to coking treatment under pressure at 600 ℃ for 6 h through program temperature control, is cooled to room temperature along with the furnace, and is crushed and ground into powder, and is sieved by a 200-mesh sieve to prepare the low-temperature carbonized powder B.
S6: 18 parts of high-carbon-residue reformed asphalt, 60 parts of low-temperature carbonized powder A in S3, 20 parts of low-temperature carbonized powder B in S5 and 2 parts of solvent pretreated raw needle coke powder are accurately weighed.
S7: putting the low-temperature carbonized powder A in the step S6, the low-temperature carbonized powder B and the raw needle coke powder pretreated by the solvent into a kneading pot, mixing at 120 ℃ for 1 h, removing water, and rotating the kneading pot at the speed of 30 r/min in the forward direction; after the moisture removal is finished, the powder is heated to 190 ℃, then high-carbon residue modified high-temperature asphalt melted at a corresponding temperature is introduced, the mixing and kneading speed is 1 h, the rotating speed of a mixing and kneading pot is 50r/min, the forward rotation and the reverse rotation are alternately carried out, and the intermittent opening and closing covers are mixed. After the mixing and kneading are finished, the paste is quickly transferred to a material hopper of a tablet rolling machine, the tablet is rolled for 2 times, the thickness of the tablet is 2 mm, the temperature of the tablet corresponds to the mixing and kneading temperature, the rotating speed is 20 r/min, the program temperature control material cooling is carried out after the tablet rolling is finished, after the temperature of the material is reduced to the room temperature, the material is crushed and ground after being placed at 10 h, and the material is placed at 10 h after being screened by a 160-mesh sieve, so as to obtain the pressed powder.
S8: pressing the pressed powder of S7 under 1 MPa to obtain a density of 1.1-1.3 g/cm 3 Is vacuum packed into bags, and is placed 5 h; placed in a cold isostatic pressing apparatus at 200MPressure is released in a gradient way after Pa is maintained for 10 min, a sample is taken out, the sealing bag is peeled off, and after 10 min of the sealing bag is placed on the shelf for h, the density of 1.63-1.66 g/cm can be obtained 3 Is a green body block of (c).
S9: placing the green body block prepared in the step S8 into a stainless steel crucible, filling with a filling material, introducing nitrogen/argon, roasting at 1050 ℃ for 4 h, cooling to 300 ℃ by program control, and naturally cooling to room temperature to obtain the green body block with the density of 1.68-1.74 g/cm 3 Is a fired block of (a). Placing the baked block in a vacuum graphitization furnace for atmosphere protection, treating at 2500 ℃ for 1 h, reducing the temperature to 200 ℃ by program control, and naturally cooling to room temperature to obtain the bulk density of 1.84 g/cm 3 Is a special graphite material.
The cross-sectional view of the special graphite material prepared in this embodiment and the morphology and back scattering of the polished surface are shown in fig. 8, wherein fig. 8 (a) is a cross-sectional view, and the left and right views of fig. 8 (b) are the morphology and back scattering of the polished surface, respectively, and as seen in fig. 8 (a), the port of the cross-section has a ductile pit, a compact structure and no through crack. As can be seen from fig. 8 (b), the special graphite material prepared in this embodiment has a compact structure, uniform pore distribution, and no macropores. The results show that the special graphite material prepared by the invention has compact structure and excellent performance.
The cross-sectional view of a special graphite material prepared by the embodiment of a commercially available foreign graphite material (marked as graphite material 1) and the morphology and back scattering view of the polished surface are shown in fig. 9, wherein fig. 9 (a) is a cross-sectional view, and the left and right views of fig. 9 (b) are the morphology and back scattering view of the polished surface respectively, and compared with the embodiment 1-3, as can be seen in fig. 9 (a), no ductile fossa is generated at the cross-sectional port of the graphite material 1, the structure is loose, and no penetrating crack is generated. As can be seen from fig. 9 (b), the graphite material 1 has a relatively loose structure (500 times) and obvious pores under the same magnification, so that more pores remain at the interface connection between particles, and the existence of partial communication holes and macropores are clearly seen. From this, the special graphite material prepared in examples 1 to 3 has better performance than graphite material 1.
The basic performance parameters of the special graphite material prepared in examples 1-3 and the basic performance parameters of the graphite material 1 are shown in Table 1.
TABLE 1 basic Performance parameter comparison Table
The above table shows that the basic performance of the special graphite material prepared by the invention is superior to that of the graphite material 1, and simultaneously, the existing standards of isostatic graphite YB/T4379-2014, electric spark processing isostatic graphite YB/T4745-2019 and casting isostatic graphite YB/T4746-2019 are also satisfied, namely: the volume density is more than or equal to 1.80 g/cm 3 The resistivity is less than or equal to 15 mu omega m, the compressive strength is more than or equal to 85 MPa, the flexural strength is more than or equal to 40 MPa, the Shore hardness is more than or equal to 50 HS, and the ash content is less than or equal to 500 ppm.
Finally, it should be noted that the above-mentioned examples of the present invention are only illustrative of the present invention and are not limiting of the embodiments of the present invention. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. Not all embodiments are exhaustive. Obvious changes and modifications which are extended by the technical proposal of the invention are still within the protection scope of the invention.
Claims (9)
1. The method for preparing the special graphite material by using the isostatic pressing graphite waste in a short process is characterized by comprising the following steps of:
s1: pretreating graphite waste powder to obtain graphite powder with D50 of 3-10 mu m, wherein the graphite waste powder is leftover materials, fragments and milling powder of isostatic pressing graphite;
s2: preparing 30-40 parts of a binder, 50-70 parts of graphite powder obtained in S1, 1-5 parts of a sulfur-containing cross-linking agent and 1-5 parts of oleic acid;
s3: putting graphite powder, a sulfur-containing cross-linking agent and oleic acid in the S2 into a kneading pot for premixing, heating to 155-185 ℃ after removing water, adding the binder in the S2 into the kneading pot for kneading after melting, rolling, crushing, grinding, compacting, carbonizing at low temperature under pressure, crushing, grinding and sieving to obtain low-temperature carbonized powder A after finishing kneading;
s4: 25-30 parts of a bonding agent, 50-80 parts of calcined coke powder, 1-5 parts of a sulfur-containing cross-linking agent and 1-5 parts of oleic acid are prepared;
s5: adding calcined coke powder, a sulfur-containing cross-linking agent and oleic acid in the step S4 into a kneading pot, removing water, heating to 155-185 ℃, adding the binder in the step S4 into the kneading pot for kneading after melting, rolling, crushing, grinding, pressing and forming after kneading, then carrying out low-temperature carbonization treatment under pressure, crushing, grinding and sieving to obtain low-temperature carbonized powder B;
s6: accurately weighing 10-20 parts of high-carbon-residue reformed asphalt, 60-70 parts of low-temperature carbonized powder A in S3, 10-20 parts of low-temperature carbonized powder B in S5, and 1-5 parts of solvent pre-treated raw coke powder;
s7: putting the low-temperature carbonized powder A, the low-temperature carbonized powder B and the solvent pretreated raw coke powder in the S6 into a kneading pot, heating to 170-200 ℃ after removing water, melting the high-carbon modified asphalt in the S6, adding into the kneading pot for kneading, and rolling, crushing and grinding to obtain pressed powder after kneading;
s8: pressing the pressed powder obtained in the step S7 into a powder with the density of 1.1-1.3 g/cm 3 Placing the block in a vacuum packaging bag for a period of time, and then placing the block in a cold isostatic pressing device for 1-3 times to obtain the block with the density of 1.63-1.66 g/cm 3 Is a green body block of (c);
s9: placing the green body block in a stainless steel crucible, burying the green body block with a burying material, placing in a roasting furnace, applying pressure, introducing nitrogen or argon in the pressure roasting process, roasting for 2-6 hours at 800-1200 ℃, performing program control cooling to 200-300 ℃, and naturally cooling to room temperature to obtain the ceramic green body with the density of 1.68-1.74 g/cm 3 Is a fired block of (a);
s10: placing the baked block in a vacuum graphitization furnace for atmosphere protection, treating for 1-4 hours at 2400-2800 ℃, performing program control, cooling to 200-300 ℃, and naturally cooling to room temperature to obtain the product with the volume density of 1.81-1.85 g/cm 3 Is a special graphite material;
wherein the sulfur-containing cross-linking agent is one or more of dodecyl mercaptan, tetramethyl thiuram disulfide, dithiodimorpholine, alkyl phenol methylol polysulfide resin, alkyl phenol sulfide or alkyl phenol polysulfide.
2. The method for preparing the special graphite material by using the isostatic pressing graphite waste in a short process according to claim 1, wherein in the step S1, firstly, metal impurities in the graphite waste powder are removed by adopting magnetic separation equipment, and the graphite waste powder is sieved and classified, then, the graphite waste powder is subjected to primary grinding by adopting a 3R Raymond mill, and then, is subjected to fine grinding by adopting an airflow mill, so that the graphite powder with the D50 of 3-10 mu m is obtained.
3. The method for preparing special graphite materials by using the isostatic pressing graphite waste in a short process according to claim 1, wherein the binder is one or more of low-temperature asphalt, modified asphalt, medium-temperature asphalt or high-temperature asphalt with low quinoline insoluble content, anthracene oil, coal tar and ethylene tar.
4. The method for preparing special graphite materials by using the isostatic pressing graphite waste in a short process according to claim 1, wherein the specific steps of S3 are as follows:
s3.1: putting graphite powder, a sulfur-containing cross-linking agent and oleic acid into a kneading pot, mixing for 1-2 hours at 110-120 ℃, removing water, and rotating the kneading pot at the rotating speed of 10-50 r/min in a forward direction;
s3.2: after the water removal is finished, heating to 155-185 ℃, adding the melted binder in the S2 into a kneading pot, kneading for 1-2 hours to obtain paste, wherein the rotating speed of the kneading pot is 10-50 r/min, forward rotation and reverse rotation are alternately performed, and intermittent opening and closing cover mixing is performed;
s3.3: after the kneading is finished, rapidly transferring the paste to a material hopper of a sheet rolling machine, rolling the sheet for 2-3 times, wherein the thickness of the rolled sheet is 1-2 mm, the temperature of the rolled sheet corresponds to the kneading temperature, and the rotating speed is 10-30 r/min;
s3.4: after finishing cooling the rolled sheet to room temperature, placing for 2-10 hours, crushing and grinding, sieving with a 100-320 mesh sieve, and placing for 2-10 hours to obtain pressed powder;
s3.5: and (3) performing compression molding under 10-20 MPa for 2-10 h, placing the obtained pressed powder in an atmosphere resistance furnace, performing pressure coking treatment at 500-650 ℃ for 2-6 h through program temperature control, cooling to room temperature along with the furnace, crushing and grinding the coked block, and sieving with a 100-200-mesh sieve to obtain the low-temperature carbonized powder A.
5. The method for preparing special graphite materials by using the isostatic pressing graphite waste in a short process according to claim 1, wherein the calcined coke powder in the step S4 is one or two of calcined pitch coke, petroleum coke and needle coke, and the D50 of the calcined coke powder is 3-10 μm.
6. The method for preparing special graphite materials by using the isostatic pressing graphite waste in a short process according to claim 1, wherein the specific steps of S5 are as follows:
s5.1: adding calcined coke powder, a sulfur-containing crosslinking agent and oleic acid into a kneading pot, mixing for 1-2 hours at 110-120 ℃, removing water, and rotating the kneading pot at the rotating speed of 10-50 r/min in a forward direction;
s5.2: after the water is removed, heating to 155-185 ℃, adding the melted binder in the step S4 into a kneading pot, kneading for 1-2 hours to obtain paste, wherein the rotating speed of the kneading pot is 10-50 r/min, forward rotation and reverse rotation are alternately performed, and intermittent opening and closing cover mixing is performed;
s5.3: after the kneading is finished, rapidly transferring the paste to a material hopper of a sheet rolling machine, rolling the sheet for 2-3 times, wherein the thickness of the rolled sheet is 1-2 mm, the temperature of the rolled sheet corresponds to the kneading temperature, and the rotating speed is 10-30 r/min;
s5.4: after finishing cooling the rolled sheet to room temperature, placing for 2-10 hours, crushing and grinding, sieving with a 100-320 mesh sieve, and placing for 2-10 hours to obtain pressed powder;
s5.5: and (3) performing compression molding under 10-30 MPa for 2-10 h, placing the obtained pressed powder in an atmosphere resistance furnace, performing pressure coking treatment at 300-600 ℃ for 2-6 h through program temperature control, cooling to room temperature along with the furnace, crushing and grinding the coked block, and sieving with a 100-200-mesh sieve to obtain the low-temperature carbonized powder B.
7. The method for preparing special graphite materials by using the short process of isostatic pressing graphite waste according to claim 1, wherein the solvent in the step S6 is used for pretreating raw coke powder into one or more of raw petroleum coke, raw pitch coke, raw needle coke or raw mesophase carbon microspheres.
8. The method for preparing special graphite materials by using the isostatic pressing graphite waste in a short process according to claim 1, wherein the specific steps of S7 are as follows:
s7.1: putting the low-temperature carbonized powder A, the low-temperature carbonized powder B and the solvent pretreated raw coke powder into a kneading pot, mixing for 1-2 hours at 110-120 ℃, removing water, and rotating the kneading pot at the rotating speed of 10-50 r/min in a forward direction;
s7.2: after the water removal is finished, heating to 240-300 ℃, melting the high-carbon residue modified asphalt in the step S6, adding the melted high-carbon residue modified asphalt into a kneading pot, kneading for 1-2 hours, wherein the rotating speed of the kneading pot is 10-50 r/min, and alternately carrying out forward rotation and reverse rotation, and intermittently opening and closing a cover for mixing;
s7.3: after the mixing and kneading are finished, rapidly transferring the mixture to a material hopper of a sheet rolling machine, rolling the sheet for 1-2 times, wherein the thickness of the rolled sheet is 1-4 mm, the temperature of the rolled sheet corresponds to the mixing and kneading temperature, the rotating speed is 10-30 r/min, performing program temperature control cooling after the rolling is finished, cooling to room temperature, placing for 2-10 h, crushing and grinding, sieving with a 100-320-mesh sieve, and placing for 2-10 h to obtain pressed powder.
9. The method for preparing special graphite materials by using the isostatic pressing graphite waste in a short process according to claim 1, wherein the specific steps of S8 are as follows:
s8.1: pressing the pressed powder obtained in the step S7 under the pressure of 1-5 MPa to obtain the powder with the density of 1.1-1.3 g/cm 3 Placing the blocks in vacuum packaging bags for 2-10 h;
s8.2: placing the mixture in cold isostatic pressing equipment, and performing gradient pressure relief after pressing for 5-30 min under 50-100 MPa;
s8.3: after the pressure relief is completed, the mixture is placed for 2 to 10 hours, pressed for 5 to 30 minutes under 150 to 200 MPa, subjected to gradient pressure relief, taken out, peeled off and packaged, and placed for 2 to 10 hours, and the density of 1.63 to 1.66g/cm is obtained 3 Is a green block of (c)A body.
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| CN101823707B (en) * | 2010-04-28 | 2011-12-14 | 四川广汉士达炭素股份有限公司 | Technical method for producing isostatic pressure graphite |
| JP2013001582A (en) * | 2011-06-13 | 2013-01-07 | Kansai Coke & Chem Co Ltd | Isotropic graphite material, and method for producing the same |
| CN102730672A (en) * | 2012-06-21 | 2012-10-17 | 湖南省长宇新型炭材料有限公司 | Production technology of large-specification extraordinary isotropic graphite material |
| CN104529450B (en) * | 2014-12-04 | 2016-11-30 | 大同新成新材料股份有限公司 | A kind of forming method of big specification isostatic pressing formed graphite goods |
| CN113387701B (en) * | 2021-06-18 | 2022-06-17 | 湖南大学 | Method for preparing high-performance carbon graphite material by pretreating raw coke powder with solvent |
| CN114702316B (en) * | 2022-03-23 | 2023-05-30 | 湖南大学 | Preparation method and application of low-cost high-purity graphite material |
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