A method for rapid thermoset conversion of bitumen

Abstract

The application discloses a method for rapidly changing asphalt into thermosetting material, which comprises the following steps: (1) crushing asphalt material into asphalt powder with particle size in micron level; (2) reacting the asphalt powder in step (1) in a pre-oxidation liquid containing hydrogen peroxide and metal-based catalyst for 0.5-1.5 hours, then filtering, rinsing and drying the slurry; (3) heating the dried powder in step (2) to 250-350 DEG C at a heating rate of 5-15 DEG C / min in an oxidizing atmosphere, and keeping the temperature for 0.5-2 hours to obtain thermosetting asphalt material. The method of the application can generate a large number of high-activity hydroxyl radicals by using hydrogen peroxide and metal-based catalyst, so as to accelerate the oxidation cross-linking reaction of asphalt and oxygen, or reduce the temperature of the cross-linking reaction of asphalt and oxygen, thereby shortening the time for changing asphalt from thermoplastic material into thermosetting material, and further effectively reducing the cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal chemical industry, and particularly relates to a method for rapidly converting bitumen into thermosetting material. BACKGROUND

[0002] In the new energy battery industry, lithium ion batteries have been widely used in electric vehicles, 3C (computer, communication and consumer electronics) fields and energy storage fields. In the new battery system, sodium ion battery system is also favored, which has similar rocking chair type charge-discharge cycle energy storage principle as lithium ion battery. The sodium ion battery industry system is similar to the lithium ion battery, so the existing industrial system of the lithium ion battery industry can be used.

[0003] The anode material of lithium ion battery / sodium ion battery has attracted widespread attention with the rapid development of lithium ion battery / sodium ion battery. Hard carbon material has isotropic structural characteristics and large interlayer spacing, which can accelerate the diffusion of lithium ions / sodium ions. At the same time, hard carbon material has good cycle performance and rate performance, low cost and other characteristics, so it has attracted widespread attention in lithium ion battery / sodium ion battery.

[0004] Bitumen is a common residue of petroleum industry, which has a wide source and low price. In addition, because its composition is mainly a mixture of some alkanes, cycloalkanes and aromatic hydrocarbons, it has a high carbon content, so it is an ideal precursor for preparing carbon materials. Before bitumen-based material is made into carbon material, it usually needs to be pre-oxidized to make bitumen complete the conversion from thermoplastic material to thermosetting material, so that it does not melt and maintains a powdery or fibrous structure in the subsequent carbonization or graphitization process. However, in the related technology, the pre-oxidation process takes a long time, which has become a major bottleneck restricting the development of bitumen-based carbon materials. SUMMARY

[0005] The present application aims to at least solve one of the technical problems in the related art, and for this purpose, the present application provides a method for rapidly converting bitumen into thermosetting material.

[0006] The method for rapidly converting bitumen into thermosetting material according to an embodiment of the present application comprises the following steps:

[0007] (1) crushing bitumen material into bitumen powder with a particle size of microns;

[0008] (2) stirring the bitumen powder of step (1) in a pre-oxidation liquid containing hydrogen peroxide and a metal-based catalyst for 0.5-1.5 hours, then filtering, rinsing and drying the slurry;

[0009] (3) The powder after drying in step (2) is heated to 250-350℃ at a heating rate of 5-15℃ / min in an oxidizing atmosphere, and kept at the temperature for 0.5-2 hours to obtain a thermosetting asphalt material.

[0010] The method for rapid thermosetting conversion of asphalt in the embodiments of the present application utilizes hydrogen peroxide and a metal-based catalyst to generate a large amount of highly active hydroxyl radicals, which can cause radical reactions of the hydrogen atoms in the condensed aromatic hydrocarbons and naphthenes in asphalt to form aromatic ring radicals, accelerate the oxidation cross-linking reaction of asphalt with oxygen, or reduce the temperature of the cross-linking reaction of asphalt with oxygen, thereby shortening the time for the conversion of asphalt from a thermoplastic material to a thermosetting material.

[0011] In some embodiments, the softening point of the asphalt material in step (1) is not less than 200℃, including one or more of petroleum asphalt, coal tar pitch, biomass pitch, or coal liquefaction residue pitch.

[0012] In some embodiments, the particle size of the asphalt powder is 10-30 microns.

[0013] In some embodiments, the pre-oxidation solution is an aqueous solution.

[0014] In some embodiments, the concentration of hydrogen peroxide in the pre-oxidation solution is 3-30%, preferably 3-10%.

[0015] In some embodiments, the concentration of the metal-based catalyst in the pre-oxidation solution is 0.1-2 mol / L, preferably 0.5-1 mol / L.

[0016] In some embodiments, the reaction temperature in step (2) is 30-50℃.

[0017] In some embodiments, the stirring rate in step (2) is 20-500 r / min.

[0018] In some embodiments, the drying temperature in step (2) is 90-150℃, and the drying time is 2-10 hours.

[0019] In some embodiments, the metal-based catalyst is a water-soluble salt of Fe 2+ , Fe 3+ , Cr 2+ , Cu + , Ce 2+ , or Mn 2+ . The soluble salt includes but is not limited to chloride, sulfate, nitrate, etc.

[0020] In some embodiments, the pH value of the pre-oxidation solution is 7.5-8.5. In some embodiments, NaOH and HCl are used to adjust the pH value of the pre-oxidation solution.

[0021] In some embodiments, the mass ratio of the pitch powder to the pre-oxidation liquid is 1:(2-5).

[0022] In some embodiments, the heating rate of step (3) is 10-15℃ / min.

[0023] In some embodiments, the oxygen content of the oxidation atmosphere of step (3) is greater than 20%.

[0024] The present application also provides a preparation method of a pitch-based hard carbon material, comprising the following steps:

[0025] (1) preparing a thermosetting pitch material by the above method;

[0026] (2) carbonizing the thermosetting pitch material in an inert atmosphere at 800-1600℃ for 0.5-2 hours to obtain a pitch-based hard carbon material.

[0027] In some embodiments, the inert atmosphere is one or more of nitrogen atmosphere, argon atmosphere or carbon dioxide atmosphere.

[0028] In some embodiments, the carbonization treatment is carried out in a fixed bed or fluidized bed carbonization furnace.

[0029] The present application also provides a pitch-based hard carbon material prepared by the above method.

[0030] In some embodiments, the pitch-based hard carbon material has one or more of spherical shape, ellipsoidal shape, cobblestone shape or irregular polygonal shape.

[0031] The present application also provides an application of the above pitch-based hard carbon material in preparing a lithium ion battery negative electrode material or a sodium ion battery negative electrode material.

[0032] The present application also provides a lithium ion battery negative electrode material comprising the above pitch-based hard carbon material.

[0033] The present application also provides a lithium ion battery negative electrode sheet comprising the above lithium ion battery negative electrode material.

[0034] The present application also provides a lithium ion battery comprising the above lithium ion battery negative electrode sheet.

[0035] The present application also provides a sodium ion battery negative electrode material comprising the above pitch-based hard carbon material.

[0036] The present application also provides a sodium ion battery negative electrode sheet comprising the above sodium ion battery negative electrode material.

[0037] The embodiment of the present application also provides a sodium ion battery, which comprises the sodium ion battery negative electrode sheet.

[0038] The present application has the following advantages and beneficial effects:

[0039] (1) The asphalt rapid thermosetting conversion method of the embodiment of the present application utilizes hydrogen peroxide and a metal-based catalyst to generate a large amount of high-activity hydroxyl radicals, so that the radical reaction of the condensed ring aromatic hydrocarbon and the cycloalkane hydrogen atom in the asphalt is caused to form an aromatic ring radical, the oxidation cross-linking reaction of the asphalt and oxygen is accelerated, or the temperature of the cross-linking reaction of the asphalt and oxygen is reduced, thereby shortening the conversion time of the asphalt from a thermoplastic material to a thermosetting material, and further effectively reducing the cost of the negative electrode material of the lithium ion battery / sodium ion battery.

[0040] (2) In the embodiment of the present application, the high-softening-point asphalt is selected as the raw material, which is widely sourced and low in price compared with the high-molecular resin, and is applied to the negative electrode material of the lithium ion battery / sodium ion battery, thereby greatly reducing the cost of the negative electrode material.

[0041] (3) The asphalt rapid thermosetting conversion method of the embodiment of the present application is simple and easy to operate, and is suitable for large-scale production and has a wide application prospect in the field of lithium ion battery / sodium ion battery materials. BRIEF DESCRIPTION OF DRAWINGS

[0042] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings, in which:

[0043] Figure 1 The SEM graph of the asphalt-based hard carbon material prepared for the embodiment 1 of the present application.

[0044] Figure 2 The XRD graph of the asphalt-based hard carbon material prepared for the embodiment 1 of the present application and the asphalt-based carbon material prepared for the comparative example 1.

[0045] Figure 3 The first cycle charge-discharge curve graph of the lithium ion battery with the hard carbon electrode sheet prepared from the asphalt-based hard carbon material prepared for the embodiment 1 of the present application as the working electrode.

[0046] Figure 4 The first cycle charge-discharge curve graph of the sodium ion battery with the hard carbon electrode sheet prepared from the asphalt-based hard carbon material prepared for the embodiment 1 of the present application as the working electrode.

[0047] Figure 5 The first cycle charge-discharge curve graph of the lithium ion battery with the electrode sheet prepared from the asphalt-based carbon material prepared for the comparative example 1 of the present application as the working electrode.

[0048] Figure 6 This is a charge-discharge curve of a sodium-ion battery using an electrode made of pitch-based carbon material prepared in Comparative Example 1 of this invention as the working electrode. Detailed Implementation

[0049] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0050] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0051] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0052] An embodiment of the present invention provides a method for rapid thermosetting transformation of asphalt, comprising the following steps:

[0053] (1) The asphalt material is crushed into asphalt powder with a particle size in the micrometer range;

[0054] (2) The asphalt powder from step (1) is reacted in a pre-oxidation solution containing hydrogen peroxide and a metal-based catalyst for 0.5 to 1.5 hours, and then the slurry is filtered, rinsed and dried.

[0055] (3) The powder dried in step (2) is heated to 250-350°C at a heating rate of 5-15°C / min under an oxidizing atmosphere and kept at the temperature for 0.5-2 hours to obtain thermosetting asphalt material.

[0056] The method for rapid thermosetting transformation of asphalt in this invention utilizes hydrogen peroxide and a metal-based catalyst to generate a large number of highly active hydroxyl radicals. These radicals can cause free radical reactions between hydrogen atoms of polycyclic aromatic hydrocarbons and cycloalkanes in the asphalt, forming aromatic ring radicals. This accelerates the oxidative crosslinking reaction between asphalt and oxygen, or lowers the temperature at which the asphalt crosslinks with oxygen, thereby shortening the time for asphalt to transform from a thermoplastic material to a thermosetting material.

[0057] In some embodiments, in step (1), the softening point of the asphalt material is not lower than 200°C, including one or more of petroleum asphalt, coal tar pitch, biomass asphalt or coal liquefaction residue asphalt.

[0058] In some embodiments, the particle size of the asphalt powder is 10 to 30 micrometers.

[0059] In some embodiments, the pre-oxidation solution is an aqueous solution.

[0060] In some embodiments, the concentration of hydrogen peroxide in the pre-oxidation solution is 3-30%; preferably 3-10%; non-limiting examples include 3%, 5%, 8%, 10%, 15%, 17%, 20%, 25%, 27%, 30%, etc.

[0061] In some embodiments, the concentration of metal-based catalyst in the pre-oxidation solution is 0.1-2 mol / L, preferably 0.5-1 mol / L. Non-limiting examples include 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.8 mol / L, 0.95 mol / L, 1 mol / L, 1.3 mol / L, 1.5 mol / L, 1.8 mol / L, 2 mol / L, etc.

[0062] In some embodiments, the reaction temperature in step (2) is 30-50°C; non-limiting examples include 30°C, 33°C, 35°C, 38°C, 40°C, 45°C, 48°C, 50°C, etc.

[0063] In some embodiments, the stirring rate in step (2) is 20-500 r / min. Non-limiting examples include a stirring rate of 20 r / min, 50 r / min, 100 r / min, 200 r / min, 300 r / min, 350 r / min, 400 r / min, 500 r / min, etc.

[0064] In some embodiments, the drying temperature in step (2) is 90-150°C; the drying time is 2-10 h. Non-limiting examples include a drying temperature of 90°C, 100°C, 110°C, 120°C, 125°C, 130°C, 140°C, 150°C, etc., and a time of 2 h, 3 h, 4.5 h, 5 h, 6 h, 7.5 h, 8 h, 10 h, etc.

[0065] In some embodiments, the metal-based catalyst is a water-soluble salt of Fe 2+ , Fe 3+ , Cr 2+ , Cu + , Ce 2+ , or Mn 2+ . The soluble salt includes but is not limited to a chloride salt, a sulfate salt, a nitrate salt, etc., non-limiting examples including FeCl3, FeCl2, Fe2(SO4)3, FeSO4, Fe(NO3)2, Fe(NO3)3, CrCl2, CuCl2, MnSO4, CuSO4, etc.

[0066] In some embodiments, the pH value of the pre-oxidation solution is 7.5-8.5. Non-limiting examples include: the pH value of the pre-oxidation solution can be 7.5, 7.6, 7.8, 8.0, 8.2, 8.5, etc.; in some embodiments, the pH value of the pre-oxidation solution is adjusted by NaOH and HCl.

[0067] In some embodiments, the mass ratio of the asphalt powder to the pre-oxidation solution is 1:(2-5), non-limiting examples include: 1:2, 1:3, 1:4, 1:4.5, or 1:5.

[0068] In some embodiments, the heating rate of step (3) is 10-15℃ / min, non-limiting examples include: 10℃ / min, 11℃ / min, 12.5℃ / min, 13℃ / min, 14℃ / min, or 15℃ / min, etc.

[0069] In some embodiments, the oxygen content of the oxidation atmosphere of step (3) is greater than 20%, non-limiting examples include: air, or a mixture of pure oxygen and air in any ratio.

[0070] The present application also provides a preparation method of an asphalt-based hard carbon material, comprising the following steps:

[0071] (1) preparing a thermosetting asphalt material by the above method;

[0072] (2) carbonizing the thermosetting asphalt material in an inert atmosphere at 800-1600℃ for 0.5-2h to obtain an asphalt-based hard carbon material.

[0073] Non-limiting examples include: the carbonization temperature of step (2) is 800℃, 900℃, 950℃, 1000℃, 1200℃, 1350℃, 1500℃, 1600℃, etc., and the holding time can be 0.5h, 0.8h, 1h, 1.2h, 1.5h, 2h, etc.

[0074] In some embodiments, the inert atmosphere is one or more of nitrogen atmosphere, argon atmosphere, or carbon dioxide atmosphere.

[0075] In some embodiments, the carbonization is carried out in a fixed bed or fluidized bed carbonization furnace.

[0076] The present application also provides an asphalt-based hard carbon material prepared by the above method.

[0077] In some embodiments, the morphology of the asphalt-based hard carbon negative electrode material is one or more of spherical, ellipsoidal, cobblestone-shaped, or irregular polygonal.

[0078] The application further provides application of the asphalt-based hard carbon negative electrode material in preparation of a lithium ion battery negative electrode material or a sodium ion battery negative electrode material.

[0079] The application further provides a lithium ion battery negative electrode material comprising the asphalt-based hard carbon material.

[0080] The application further provides a lithium ion battery negative electrode sheet comprising the lithium ion battery negative electrode material.

[0081] The application further provides a lithium ion battery comprising the lithium ion battery negative electrode sheet.

[0082] The application further provides a sodium ion battery negative electrode material comprising the asphalt-based hard carbon material.

[0083] The application further provides a sodium ion battery negative electrode sheet comprising the sodium ion battery negative electrode material.

[0084] The application further provides a sodium ion battery comprising the sodium ion battery negative electrode sheet.

[0085] The following are typical but non-limiting embodiments of the application, and it should be noted that the schemes of the following comparative examples are not prior art, but are set only for comparison with the schemes of the embodiments, and do not limit the application.

[0086] The carbon materials prepared in the embodiments and comparative examples of the application are prepared into lithium ion batteries or sodium ion batteries according to the following method, and the electrochemical performance is measured.

[0087] Lithium ion battery: carbon material, conductive agent (Super P) and binder (CMC2200 & SBR307) were weighed according to a certain mass ratio (the mass ratio of the four materials was 8:1:0.5:0.5) and used as prepared. First, a proper amount of deionized water was added to the stirring tank as a solvent, and then CMC2200 was added to the stirring tank. The stirring tank was stirred at a speed of 600 rpm for 30 min under vacuum. The conductive agent (Super P) was weighed and added to the stirring tank. First, the stirring tank was stirred at a speed of 100 rpm for 10 min under vacuum, and then the stirring tank was stirred at a speed of 600 rpm for 90 min under vacuum. The carbon material was weighed and added to the stirring tank. First, the stirring tank was stirred at a speed of 100 rpm for 10 min under vacuum, and then the stirring tank was stirred at a speed of 600 rpm for 60 min under vacuum. Finally, SBR307 was weighed and added to the stirring tank. The stirring tank was stirred at a speed of 600 rpm for 30 min under vacuum. The prepared slurry was coated on a copper foil current collector with a coating thickness of 15 μm. After coating, drying was performed in a vacuum drying oven at a drying temperature of 110°C for 12 h, followed by rolling (roll thickness was 5 μm, and the compaction density was 1.5-2.0). After rolling, the die was cut into a circular electrode with a diameter of 14 mm. The punched electrode was placed in a glove box filled with high-purity argon atmosphere for assembly of a CR2032 type button cell. Lithium metal was used as the counter electrode, the electrode was used as the working electrode, and a polypropylene macroporous membrane was used as the separator (Celgard 2400). The assembly sequence was as follows: first, the lithium metal was placed in the negative electrode shell, then the separator soaked with electrolyte was placed, 100 μL of electrolyte (the electrolyte was a mixed solution of 1 mol / L lithium hexafluorophosphate dissolved in ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio was 1:1)) was injected, then the electrode with active material was placed with the active material facing the separator, and then the gasket, spring sheet and positive electrode shell were sequentially placed. After pressing out the excess electrolyte, the battery was placed in a sealing machine for packaging, and was left to stand at room temperature for 24 h.

[0088] Sodium ion battery: carbon material, conductive agent (Super P) and binder (CMC2200 & SBR307) were weighed according to a certain mass ratio (the mass ratio of the four materials was 8:1:0.5:0.5) and used (a certain amount of deionized water was added to the stirring tank as a solvent, then CMC2200 was added to the stirring tank, and vacuum stirring was carried out at a speed of 600 r / min for 30 min; the weighed conductive agent (Super P) was added to the stirring tank, first vacuum stirring at a speed of 100 r / min for 10 min, then vacuum stirring at a speed of 600 r / min for 90 min; the weighed carbon material was added to the stirring tank, first vacuum stirring at a speed of 100 r / min for 10 min, then vacuum stirring at a speed of 600 r / min for 60 min; finally, SBR307 was added to the stirring tank, and vacuum stirring was carried out at a speed of 600 r / min for 30 min; the prepared slurry was coated on a copper foil current collector, and the coating thickness was 15 μm. After coating, drying was carried out in a vacuum drying oven, the drying temperature was 110°C, and the drying time was 12 h, then rolling (the rolling thickness was 5 um, and the compaction density was 1.5-2.0). After rolling, the sheet punching machine was used to cut the pole piece into a circular pole piece with a diameter of 14 mm. The punched pole piece was placed in a glove box filled with high-purity argon atmosphere for assembly of CR2032 type button cell. Sodium metal sheet was used as the counter electrode, the pole piece was used as the working electrode, and glass fiber was used as the separator. The assembly sequence was as follows: first, the sodium metal sheet was placed in the negative electrode shell, then the separator soaked with electrolyte was placed, 100 μL of electrolyte (the electrolyte was a mixed solution of 1 mol / L sodium hexafluorophosphate dissolved in ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio 1:1)) was injected, then the electrode with active material was placed with the active material facing the separator, and then the gasket, spring sheet and positive electrode shell were sequentially placed. After lightly pressing the excess electrolyte, the battery was placed in a sealing machine for packaging, and was left to stand at room temperature for 24 h.

[0089] Example 1

[0090] A preparation method of a pitch-based hard carbon material, comprising the following steps:

[0091] (1) The high softening point coal tar pitch with a softening point of 240°C prepared from medium temperature coal tar pitch is crushed into pitch powder with a particle size D50 of 20 microns;

[0092] (2) 2L of pre-oxidized liquid is added to the reaction kettle, the composition of the pre-oxidized liquid is that the hydrogen peroxide content is 10%, the FeSO4 content is 0.5 mol / L, and the pH value is adjusted to 8 by NaOH and HCl;

[0093] (3) 500g of the pitch powder prepared in step (1) is added to the reaction kettle, and the reaction is carried out at 35°C and a stirring speed of 100 r / min for 1h; then the slurry is filtered and washed with clean water until the pH value is about 7, and then dried at 100°C for 2h;

[0094] (4) The dried powder is placed in an oxidation rotary furnace, and is heated from room temperature to 300°C at a rate of 10°C / min under an oxidation atmosphere (a mixture of pure oxygen and air, and the oxygen accounts for 30% in the oxidation atmosphere), and is kept at 300°C for 1 hour. The blocky material is broken and sieved to below 30 microns to obtain a thermosetting pitch material;

[0095] (5) The thermosetting pitch material of step (4) is carbonized in a rotary carbonization furnace at 1000°C under a nitrogen atmosphere, and the heating rate is 10°C / min, and the holding time is 1 hour. The blocky material is broken and sieved to a particle size of less than 30 microns to obtain the pitch-based hard carbon material.

[0096] Example 2

[0097] A preparation method of a pitch-based hard carbon material, comprising the following steps:

[0098] (1) A high softening point coal pitch with a softening point of 240°C prepared from medium temperature coal pitch is crushed to an asphalt powder with a particle size D50 of 20 microns;

[0099] (2) 2L of a pre-oxidation solution is added into a reaction kettle, and the pre-oxidation solution comprises 15% of hydrogen peroxide and 0.8 mol / L of FeSO4, and the pH value is adjusted to 8 by NaOH and HCl;

[0100] (3) 500g of the asphalt powder prepared in step (1) is added into the reaction kettle, and is reacted at 35°C for 1.5 hours under a stirring rate of 300r / min. Then the slurry is filtered, washed with clean water until the pH value is about 7, and then is dried at 100°C for 2 hours;

[0101] (4) The dried powder is placed in an oxidation rotary furnace, and is heated from room temperature to 350°C at a rate of 10°C / min under an oxidation atmosphere (a mixture of pure oxygen and air, and the oxygen accounts for 30% in the oxidation atmosphere), and is kept at 350°C for 1.2 hours. The blocky material is broken and sieved to below 30 microns to obtain a thermosetting pitch material;

[0102] (5) The thermosetting pitch material of step (4) is carbonized in a rotary carbonization furnace at 1000°C under a nitrogen atmosphere, and the heating rate is 10°C / min, and the holding time is 1 hour. The blocky material is broken and sieved to a particle size of less than 30 microns to obtain the pitch-based hard carbon material.

[0103] Example 3

[0104] A preparation method of a pitch-based hard carbon material, comprising the following steps:

[0105] (1) high softening point coal pitch with a softening point of 240 DEG C prepared from medium temperature coal pitch is crushed into pitch powder with a particle size D50 of 20 microns;

[0106] (2) 2L of pre-oxidized solution is added into the reaction kettle, the pre-oxidized solution has a hydrogen peroxide content of 5% and a FeSO4 content of 1 mol / L, and the pH value is adjusted to 8 by NaOH and HCl;

[0107] (3) 500g of the pitch powder prepared in step (1) is added into the reaction kettle, and the reaction is carried out at 35 DEG C for 1h under a stirring speed of 150 r / min; then the slurry is filtered, washed with clean water until the pH value is about 7, and then dried at 100 DEG C for 2h;

[0108] (4) the dried powder is placed in an oxidation rotary furnace, and is heated from room temperature to 350 DEG C at a rate of 15 DEG C / min under an oxidation atmosphere (mixed gas of pure oxygen and air, and the oxygen accounts for 30% in the oxidation atmosphere), and is kept at 350 DEG C for 1h; the blocky material is broken and sieved to below 30 microns to obtain a thermosetting pitch material;

[0109] (5) the thermosetting pitch material of step (4) is carbonized in a rotary carbonization furnace at 1100 DEG C under a nitrogen atmosphere, the heating rate is 10 DEG C / min, and the holding time is 1h; the blocky material is broken and sieved to a particle size of less than 30 microns to obtain the pitch-based hard carbon material.

[0110] Example 4

[0111] A preparation method of a pitch-based hard carbon material, comprising the following steps:

[0112] (1) high softening point coal pitch with a softening point of 240 DEG C prepared from medium temperature coal pitch is crushed into pitch powder with a particle size D50 of 20 microns;

[0113] (2) 2L of pre-oxidized solution is added into the reaction kettle, the pre-oxidized solution has a hydrogen peroxide content of 5% and a FeSO4 content of 1 mol / L, and the pH value is adjusted to 8 by NaOH and HCl;

[0114] (3) 500g of the pitch powder prepared in step (1) is added into the reaction kettle, and the reaction is carried out at 35 DEG C for 1h under a stirring speed of 150 r / min; then the slurry is filtered, washed with clean water until the pH value is about 7, and then dried at 100 DEG C for 2h;

[0115] (4) the dried powder is placed in an oxidation rotary furnace, and is heated from room temperature to 350 DEG C at a rate of 15 DEG C / min under an oxidation atmosphere (mixed gas of pure oxygen and air, and the oxygen accounts for 30% in the oxidation atmosphere), and is kept at 350 DEG C for 1h; the blocky material is broken and sieved to below 30 microns to obtain a thermosetting pitch material;

[0116] (5) The thermosetting pitch material of step (4) is carbonized in a rotary carbonization furnace at 1200℃ under a nitrogen atmosphere, with a heating rate of 10℃ / min and a holding time of 1h; the block material is broken up and sieved to a particle size of less than 30 microns, thereby obtaining the pitch-based hard carbon material.

[0117] Example 5

[0118] A method for preparing a pitch-based hard carbon material, comprising the following steps:

[0119] (1) A high softening point coal pitch with a softening point of 240℃, prepared from medium temperature coal pitch, is pulverized to a pitch powder with a particle size D50 of 20 microns;

[0120] (2) 2L of a pre-oxidation solution is added to the reaction kettle, the pre-oxidation solution having a composition of 20% hydrogen peroxide and 1.5mol / L FeSO4, and the pH value is adjusted to 8.5 using NaOH and HCl;

[0121] (3) 500g of the pitch powder prepared in step (1) is added to the reaction kettle, and the slurry is stirred at 35℃ and a stirring rate of 100r / min for 0.8h; then the slurry is filtered and washed with clean water until the pH value is about 7, and then dried at 100℃ for 2h;

[0122] (4) The dried powder is placed in an oxidation rotary furnace under an oxidation atmosphere (a mixture of pure oxygen and air, with the oxygen content being 30%), and heated from room temperature to 250℃ at a rate of 5℃ / min, and held at 250℃ for 1h; the block material is broken up and sieved to less than 30 microns, thereby obtaining a thermosetting pitch material;

[0123] (5) The thermosetting pitch material of step (4) is carbonized in a rotary carbonization furnace at 1000℃ under a nitrogen atmosphere, with a heating rate of 10℃ / min and a holding time of 1h; the block material is broken up and sieved to a particle size of less than 30 microns, thereby obtaining the pitch-based hard carbon material.

[0124] Comparative Example 1

[0125] A method for preparing a pitch-based carbon material, comprising the following steps:

[0126] The high softening point coal tar powder prepared from the medium temperature coal tar is coarsely crushed to a coarse particle with a particle size D50 of 35.4 microns, and the coarse particles are loaded into an air flow mill for circulating crushing to obtain particles with a particle size D50 of 13 microns. The particles are placed in an oxidation rotary furnace, and are oxidized at 350°C for 2 hours under an oxidation atmosphere (a mixed gas of pure oxygen and air, and the oxygen accounts for 30% in the oxidation atmosphere) at a temperature rising rate of 10°C / min from room temperature to 350°C. The obtained oxidized particles are placed in a 1000°C rotary or fixed bed carbonization furnace for carbonization under a nitrogen atmosphere, and the temperature rising rate is 10°C / min. The temperature is raised to 1000°C and kept for 1 hour. The bulk material is dispersed and sieved to a particle size less than 30 microns, and a pitch-based carbon material is obtained.

[0127] Figure 1 Figure 1 is a SEM image of the pitch-based hard carbon material prepared in Example 1 of the present application. The pitch-based hard carbon material is prepared by the method of the present application. Figure 1 It can be seen that the pitch-based hard carbon material has a spherical, ellipsoidal, pebble or irregular polygonal morphology, and the D50 is 4 microns.

[0128] Figure 2 Figure 2 is an XRD image of the pitch-based hard carbon material prepared in Example 1 of the present application and the pitch-based carbon material prepared in Comparative Example 1. The pitch-based hard carbon material is prepared by the method of the present application. Figure 2 It can be seen that the carbon material of Comparative Example 1 produces a sharp graphite peak near 26°, indicating that the pitch material has undergone an intermediate phase transformation process to form soft carbon that is easy to graphitize, while the carbon material obtained by the rapid heat treatment method of the present application (Example 1) does not undergo an intermediate phase transformation process and is successfully converted into amorphous hard carbon material.

[0129] Figure 3 Figure 3 is a first cycle charge-discharge curve of a lithium ion battery with a hard carbon electrode prepared from the pitch-based hard carbon material prepared in Example 1 of the present application as a working electrode. The tested rate is 0.1C, and the test voltage interval is 0-2.0V. The first discharge capacity is 381.5 mAh / g, and the first coulombic efficiency is 82.1%.

[0130] Figure 4 Figure 4 is a first cycle charge-discharge curve of a sodium ion battery with a hard carbon electrode prepared from the pitch-based hard carbon material prepared in Example 1 of the present application as a working electrode. The tested rate is 0.1C, and the test voltage interval is 0-2.0V. The first discharge capacity is 248 mAh / g, and the first coulombic efficiency is 80%.

[0131] Figure 5 Figure 5 is a first cycle charge-discharge curve of a lithium ion battery with an electrode prepared from the pitch-based carbon material prepared in Comparative Example 1 of the present application as a working electrode. The tested rate is 0.1C, and the test voltage interval is 0-2.0V. The first discharge capacity is 257 mAh / g, and the first coulombic efficiency is 65.0%.

[0132] Figure 6 is the first cycle charge-discharge curve of a sodium ion battery with the working electrode of the asphalt-based carbon material prepared in Comparative Example 1 of the present application, the tested rate is 0.1C, the test voltage range is 0-2.0V, the first discharge capacity is 211mAh / g, and the first coulombic efficiency is 58.0%.

[0133] In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited.

[0134] In the present application, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that the specific feature, structure, material or characteristic being described is included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples, without contradiction.

[0135] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A method for the rapid thermoset conversion of bitumen, characterized in that, The method comprises the following steps: (1) crushing the asphalt material into asphalt powder with a particle size of microns; (2) the asphalt powder of step (1) is stirred in a pre-oxidation solution containing hydrogen peroxide and a metal-based catalyst for 0.5-1.5 hours, and then the slurry is filtered, rinsed, and dried; the metal-based catalyst is a water-soluble salt of Fe 2+ , Fe 3+ , Cr 2+ , Cu + , Ce 2+ , or Mn 2+ ; (3) heating the powder dried in step (2) to 250-350℃ at a heating rate of 5-15℃ / min in an oxidizing atmosphere, and keeping the temperature constant for 0.5-2 hours to obtain a thermosetting asphalt material.

2. The method for rapid thermoset conversion of bitumen according to claim 1, characterized in that, The asphalt material in step (1) has a softening point of no less than 200℃, and comprises one or more of petroleum asphalt, coal tar pitch, biomass pitch or coal liquefaction residue pitch.

3. The method for rapid thermoset conversion of bitumen according to claim 1, characterized in that, The particle size of the asphalt powder is 10-30 microns.

4. The method for rapid thermoset conversion of bitumen according to claim 1, characterized in that, The pre-oxidation solution is an aqueous solution, the concentration of hydrogen peroxide in the pre-oxidation solution is 3-30%, and the concentration of the metal-based catalyst in the pre-oxidation solution is 0.1-2 mol / L.

5. The method for rapid thermoset conversion of bitumen according to claim 4, characterized in that, The pre-oxidation solution is an aqueous solution, the concentration of hydrogen peroxide in the pre-oxidation solution is 3-10%, and the concentration of the metal-based catalyst in the pre-oxidation solution is 0.5-1 mol / L.

6. The method for rapid thermoset conversion of bitumen according to claim 1, characterized in that, The reaction temperature in step (2) is 30-50℃; Optionally, the pH value of the pre-oxidation solution is 7.5-8.5; Optionally, the mass ratio of the asphalt powder to the pre-oxidation solution is 1:(2-5).

7. The method for rapid thermoset conversion of bitumen as claimed in claim 1 wherein, The oxygen content of the oxidizing atmosphere in step (3) is greater than 20%. ​ 8. A method for producing pitch-based hard carbon material, characterized by, The method comprises the following steps: (1) preparing a thermosetting asphalt material by the method of any one of claims 1-7; (2) carbonizing the thermosetting asphalt material in an inert atmosphere at 800-1600℃ for 0.5-2 hours to obtain the asphalt-based hard carbon material; Optionally, the inert atmosphere is one or more of a nitrogen atmosphere, an argon atmosphere or a carbon dioxide atmosphere.

9. A pitch-based hard carbon material, characterized by, The asphalt-based hard carbon material is prepared by the method of claim 8.

10. The use of the asphalt-based hard carbon material of claim 9 in the preparation of a lithium ion battery negative electrode material or a sodium ion battery negative electrode material.

11. A battery negative electrode material, an electrode sheet or a battery comprising the asphalt-based hard carbon material of claim 9.

Images