Process for continuous graphitization production of negative electrode material

Abstract

A process for continuous graphitization production of a negative electrode material. The process comprises: pre-treating a carbon source to obtain a carbon micropowder; mixing the carbon micropowder with an additive and then pressing the mixture to obtain carbon spheres having a free fall crushing strength value of 300 mm to 800 mm; and performing continuous gradient drying and baking on the carbon spheres, then performing vertical continuous carbonization and graphitization to obtain graphitized particles having a free fall crushing strength value of 150 mm to 450 mm, and then performing post-treatment. The present application can achieve effective conversion of high-melting-point and high-boiling-point elemental metal and compound impurities in the obtained graphitized particles into low-boiling-point compounds, and achieve reduction in the eutectic point by blending, thereby avoiding enrichment, coking, and caking of high-melting-point impurities in a graphitization furnace. In addition, the process used in the present application ensures stable graphitization, low powder loss rate, high tap density of the obtained negative electrode material, and minimal low-value by-products.

Description

Process for continuous graphitization production of negative electrode material TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon materials, in particular to a negative electrode material, and more particularly to a process for continuous graphitization production of negative electrode material. BACKGROUND

[0002] The existing process for producing artificial graphite negative electrode material includes sequentially crushing, grinding, grading, coating and granulating, carbonization, briquetting, and graphitization of raw materials. The equipment used in each process is intermittent or discontinuous. For example, the carbonization adopts crucible loading, covers the crucible cover, and then puts it into the tunnel kiln to heat and rise to about 1000℃, and then gradually cools down to near room temperature. After carbonization, the material in the crucible is sucked out and packaged by negative pressure method, and then graphitized. This intermittent carbonization process and method has the disadvantages of bad reaction, morphology destruction, specific surface area change, material burning loss, and large energy waste, etc. due to the entrainment of H2O and O2 in the material or the introduction of O2 during the cooling process. In addition, the conventional graphitization mainly adopts Acheson furnace, inner string furnace or compartment furnace, loads the material into the crucible or compartment, covers the cover, lays the covering material, heats, insulates, cools, opens the furnace, and unloads and packages. The graphitization cycle of these intermittent processes is long, the energy consumption is large, the cost is high, the smoke generated during the operation process is difficult to collect and process in an orderly manner, which easily causes environmental pollution and has safety hazards of spraying furnace; secondly, air and moisture are also entrained in the material during loading, which has certain adverse reactions during the heating process; in addition, a large amount of covering material is used in the process, resulting in a large amount of low-value by-products.

[0003] In recent years, many researchers have explored the process and equipment for continuous graphitization production. Some adopt carbonization and graphitization parallel integrated furnace, which connects the carbonization cavity and the graphitization cavity in parallel, and each independently feeds, heats, cools, and discharges. This parallel integrated furnace uses the outer wall of the ultra-high temperature graphitization cavity as the inner wall of the carbonization cavity, and the low-temperature carbonization material continuously moves downward to quickly take away the heat energy of the graphitization outer wall, which results in that the temperature in the graphitization furnace cannot be raised, and the temperature inside the carbonization cavity is too high, which wastes energy and makes it difficult to obtain qualified graphitized products. Some adopt horizontal and vertical collaborative continuous graphitization process and device, and carbon micro-powder is coated and carbonized in the horizontal rotary drum furnace of the combined device, and graphitized in the vertical furnace of the combined device, which collaboratively produces continuously. The coating of carbon micro-powder in the rotary drum results in poor compactness and low tap density of the obtained product, which easily leads to uneven dispersion of graphite negative electrode particles and decreased conductivity.

[0004] At present, in order to overcome the long process cycle and high energy consumption of the intermittent graphitization process such as Acheson furnace, inner string furnace or compartment furnace, vertical continuous graphitization process and equipment have become one of the popular research and development directions. However, the vertical continuous graphitization process requires that the charging material is in the form of particles, not in the form of powder, otherwise the high volatile point impurities in the furnace will be gasified and overflowed, which will wash away the carbon powder, and when the gas overflow channel is not smooth, the furnace will be blown out. In addition, the high melting point impurities are easy to be enriched and caked in the vertical continuous graphitization furnace, which will block the gas overflow channel of the graphitization, causing the hidden danger of blowing out the furnace. Therefore, how to use vertical continuous graphitization for continuous graphitization production and ensure that the carbon powder can be stably charged in the furnace is a problem that needs to be considered in the continuous graphitization production.

[0005] Application content

[0006] In view of the above problems, the purpose of the present application is to provide a process for continuous graphitization production of negative electrode material, which not only can ensure that the carbon powder can be stably graphitized and reduce the loss rate of running powder, but also can realize continuous graphitization production to obtain negative electrode material with less low-value by-products and high tap density.

[0007] In order to achieve the above purpose, the present application provides a process for continuous graphitization production of negative electrode material, comprising:

[0008] (I) pretreating a carbon source to obtain carbon powder;

[0009] (II) mixing the carbon powder and an additive and then pressing to obtain carbon balls with a free-fall breakage resistance value of 300 mm to 800 mm;

[0010] (III) baking the carbon balls in a continuous gradient drying oven, then performing vertical continuous carbonization and graphitization to obtain graphitized particles with a free-fall breakage resistance value of 150 mm to 450 mm, and then performing post-treatment.

[0011] In the technical solution of the present application, the carbon microspheres are pressed under the action of the additive to obtain carbon balls with a free-fall breakage resistance value of 300 mm to 800 mm, and the free-fall breakage resistance value of the graphitized carbon balls after graphitization is 150 mm to 450 mm. By controlling the free-fall breakage resistance value of the carbon balls within a certain range, it can not only ensure that the carbon balls are not easily washed away by the overflow gas even if they enter the vertical continuous graphitization equipment, and the loss rate of running powder is low, but also avoid that the material surface is rough and the tap density is small during subsequent treatment due to too high strength. In addition, the carbon balls with a free-fall breakage resistance value of 300 mm to 800 mm are baked in a continuous gradient drying oven, which can ensure the continuity before graphitization, and then the vertical continuous carbonization and graphitization can ensure the continuity of drying and baking and carbonization and graphitization, so that continuous graphitization production can be realized.

[0012] As a technical scheme of the present application, the additive comprises a dry powder composite additive and a liquid composite additive.

[0013] As a technical scheme of the present application, the mass ratio of the carbon micro powder, the dry powder composite additive and the liquid composite additive is 50:100:0.5-10.00.

[0014] As a technical scheme of the present application, the average particle size of the dry powder composite additive is 0.01-100.00 μm.

[0015] As a technical scheme of the present application, the mass ratio of the carbon micro powder and the liquid composite additive is 50:100:6-25.

[0016] As a technical scheme of the present application, the additive is mixed by first mixing the dry powder composite additive and then mixing the liquid composite additive.

[0017] As a technical scheme of the present application, the dry powder composite additive comprises at least two of resin powder, glue powder and inorganic salt powder.

[0018] As a technical scheme of the present application, the resin powder comprises at least one of phenolic resin, modified urea-formaldehyde resin and pitch, the glue powder comprises at least one of redispersible glue powder, cellulose powder, alpha starch, polyvinyl alcohol glue powder and latex powder, and the inorganic salt powder comprises at least one of sodium silicate, calcium chloride, ferric chloride, ferrous chloride and aluminum phosphate.

[0019] As a technical scheme of the present application, the liquid composite additive comprises at least two of resin glue, inorganic acid, inorganic salt solution and solvent.

[0020] As a technical scheme of the present application, the resin glue comprises at least one of urea-formaldehyde resin glue, epoxy resin glue, phenolic resin glue, liquid pitch glue and latex, the inorganic acid comprises at least one of nitric acid, phosphoric acid, sulfuric acid and hydrochloric acid, the inorganic salt solution comprises at least one of water glass, calcium chloride solution, ferric chloride solution and ferrous chloride solution, and the solvent comprises at least one of water, ethanol, methanol, acetone, xylene, dipropylene glycol dimethyl ether, ethylene glycol monomethyl ether and propylene glycol methyl ether.

[0021] As a technical scheme of the present application, the carbon sphere is first dried at a gradient of 30-105℃, then baked at a gradient of 105-300℃ until the water content is below 0.01 wt.%, and then subjected to the carbonization and graphitization.

[0022] As a technical scheme of the present application, the baking and the graphitization further comprise a pre-carbonization process, and the baking, the pre-carbonization and the graphitization are of an integrated structure.

[0023] As a technical solution of the present application, the temperature of the pre-carbonization treatment is 500-2200°C.

[0024] As a technical solution of the present application, the time of the pre-carbonization treatment is 2-20h.

[0025] As a technical solution of the present application, the pre-carbonization treatment is carried out under the condition that the differential pressure of the overflow gas is controlled to be 0-+25Pa.

[0026] As a technical solution of the present application, the vertical continuous graphitization is carried out under the condition that the differential pressure of the overflow gas is controlled to be 0-+25Pa, and the graphitization discharge area is discharged under the condition of mechanical closed gas and oxygen.

[0027] As a technical solution of the present application, the pre-treatment comprises crushing the carbon source to a particle size of 0.01-5.00mm, and then grinding to obtain the carbon powder with a particle size of 5-25μm.

[0028] As a technical solution of the present application, the pressing comprises buffering the mixed material, and then pressing the ball in the ball press to obtain the carbon ball with a particle size of 5-35mm.

[0029] As a technical solution of the present application, the temperature of the vertical continuous graphitization is 2200-3300°C.

[0030] As a technical solution of the present application, the time of the vertical continuous graphitization is 6-36h. As a technical solution of the present application, the power of the vertical continuous graphitization is 400-2700KW. As a technical solution of the present application, the post-treatment comprises scattering and grading to obtain the particle with a particle size of 5-30μm. BRIEF DESCRIPTION OF DRAWINGS

[0031] Fig. 1 is a morphology diagram of the negative electrode material prepared in Example 1.

[0032] Fig. 2 is a morphology diagram of the negative electrode material prepared in Example 2.

[0033] Fig. 3 is a morphology diagram of the negative electrode material prepared in Example 3.

[0034] Fig. 4 is a morphology diagram of the negative electrode material prepared in Example 4.

[0035] Fig. 5 is a morphology diagram of the negative electrode material prepared in Comparative Example 1. DETAILED DESCRIPTION

[0036] The application provides a continuous graphitization production process of artificial graphite material, which can avoid problems such as long cycle, high energy consumption and many low-value byproducts caused by traditional intermittent operation, eliminate problems such as easy enrichment of high-melting-point impurities in the vertical continuous graphitization furnace, coking and blocking of the graphitization gas overflow channel, and hidden dangers of the furnace, and overcome problems such as low yield of the graphitized product caused by powder running in the furnace and poor product quality caused by the need for crushing and grinding of the obtained graphitized particles.

[0037] The application provides a continuous graphitization production process of a negative electrode material, which comprises steps (1), (2) and (3).

[0038] In step (1), the carbon source is pretreated to obtain carbon powder. The pretreatment comprises crushing the carbon source to a particle size of 0.01 mm to 5.00 mm and then grinding to obtain carbon powder with a particle size of 5 μm to 25 μm. The particle size of the obtained carbon powder can be, but is not limited to, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 13 μm or 25 μm. The carbon source can be one or a mixture of multiple kinds. The carbon sources are uniformly mixed, the particle size, volatile matter content and carbon content or impurity content are made consistent, and the crushing and grinding parameters are adjusted to obtain uniform carbon powder. The uniform carbon powder has consistent characteristics, which is beneficial to the stable adjustment of the additive and the compression of carbon balls with stable quality. The carbon balls with stable quality do not have fluctuations in the strength of carbon particles, do not easily break and pulverize, and do not cause subsequent roasting and graphitization to be difficult to proceed. The carbon balls with too high strength cannot be easily dispersed after graphitization, and need to be broken and ground, which causes the product to have a rough surface, a small tap density and a large specific surface area.

[0039] The uniformly mixed carbon sources are continuously and automatically fed into a crusher, and are crushed to a particle size of 0.01 mm to 5.00 mm. The particle size can be, but is not limited to, 0.01 mm, 0.05 mm, 0.10 mm, 0.5 mm, 1.00 mm, 2.00 mm, 3.00 mm, 4.00 mm or 5.00 mm. Too fine crushing leads to too fine carbon powder after grinding, and low qualified product rate. Too coarse crushing leads to low grinding efficiency of the carbon powder.

[0040] In step (2), the carbon powder and the additive are mixed and compressed to obtain carbon balls with a free-fall breakage resistance value of 300 mm to 800 mm.

[0041] The additive includes dry powder composite additive and liquid composite additive. The additive of the present application is compounded by using dry powder composite additive and liquid composite additive. The dry powder composite additive and carbon micro-powder are kneaded into a certain strength (free fall anti-breaking strength value is 300mm to 800mm) by using the adhesion of the liquid composite additive. The dry powder composite additive is uniformly dispersed on the surface of the carbon micro-powder under the action of the liquid additive. The dry powder composite additive is further improved to 400mm to 1300mm after heat melting and subsequent gradient drying. In addition, the dry powder composite additive has high flowability after heat melting, which can fill into the holes, pits or grooves of the carbon micro-powder, so that the carbon micro-powder can obtain a round appearance and increase the tap density.

[0042] Further, the mass ratio of the carbon micro-powder and the dry powder composite additive is 50:100:0.50-10.00, which can be but not limited to 100:0.5, 100:0.75, 100:1.00, 100:2.00, 100:3.00, 100:4.00, 100:5.00, 100:6.00, 100:7.00, 100:8.00, 100:9.00, 100:10.00, 50:8.00, 50:10.00, 70:7.00, 80:7.00, 90:7.00. The particle size of the dry powder composite additive is 0.01μm to 100.00μm, which can be but not limited to 0.01μm, 0.10μm, 1.00μm, 10.00μm, 20.00μm, 30.00μm, 40.00μm, 50.00μm, 60.00μm, 70.00μm, 80.00μm, 90.00μm, 100.00μm.

[0043] The dry powder composite additive includes at least one of resin powder, glue powder and inorganic salt powder. The resin powder includes at least one of phenolic resin, modified urea-formaldehyde resin and pitch. The glue powder includes at least one of redispersible glue powder, polyvinyl alcohol glue powder, cellulose powder, a starch and latex powder. The inorganic salt powder includes at least one of sodium silicate, calcium chloride, ferric chloride, ferrous chloride and aluminum phosphate. Among them, the pitch powder and the phenolic resin powder in the resin powder, the polyvinyl alcohol powder and the redispersible glue powder in the glue powder, and the calcium chloride in the inorganic salt powder are used in combination, and the performance is best. This may be due to the fact that the polyvinyl alcohol can provide good initial strength to the particles and provide certain late strength, water is cheap and safe as a solvent, in addition, there are two common polymerization degree products of polyvinyl alcohol 1788 and polyvinyl alcohol 2488, and the polymerization degree and viscosity can be adjusted according to the different needs of the carbon powder granulation; the redispersible glue powder can provide good initial strength to the particles, and also has certain water-reducing effect, that is, appropriately reducing the amount of water and improving the compactness of the briquettes; the pitch powder can provide good medium and late strength to the particles and maintain good graphitization degree; the phenolic resin powder can provide good medium and late strength to the particles, and can also appropriately reduce the graphitization degree according to the needs of the product; the calcium chloride powder can be used in combination when selecting resin glue and organic solvent granulation, which can eliminate the safety hazard of high-melting-point impurities accumulating and coking in the graphitization furnace.

[0044] The dry powder composite additive is mixed first, and then the liquid composite additive is mixed. The dry powder composite additive can be mixed by using a conventional mixer, such as but not limited to a double-screw mixer, a ribbon mixer, a horizontal plow mixer or a mortar mixer. The carbon powder and the dry powder composite additive are fed into a dry-wet mixer under a micro-negative pressure condition while being stirred, and after the feeding is completed, the mixing chamber is closed and the dry mixing is uniform, which is beneficial to the rapid mixing of the materials. The mixing of the liquid composite additive can be performed by using a dry-wet mixer, spraying and other conventional solid+liquid mixing methods. After the carbon powder and the dry powder composite additive are uniformly dry-mixed, the liquid composite additive is mixed to obtain a kneaded state with uniform dispersion of components.

[0045] The mass ratio of the carbon powder and the liquid composite additive is 50-100:6-25, which can be but is not limited to 100:6, 100:8, 100:10, 100:12, 100:15, 100:18, 100:20, 100:22, 100:23, 100:25, 50:25, 50:20, 50:15, 50:10, 70:25, 70:20, 70:15, 70:10. The liquid composite additive includes at least two of resin glue, inorganic acid, inorganic salt solution and solvent. The resin glue includes at least one of urea-formaldehyde resin glue, epoxy resin glue, phenolic resin glue, liquid asphalt glue and latex. The inorganic acid includes at least one of nitric acid, phosphoric acid, sulfuric acid and hydrochloric acid, and the inorganic acid mainly functions to convert high-melting-point and high-boiling-point impurities into low-melting-point and low-boiling-point compounds so as to be gasified and removed at a lower temperature. The inorganic salt solution includes at least one of water glass, calcium chloride solution, ferric chloride solution and ferrous chloride solution, and one of the main functions of the inorganic salt solution is to form a blend with high-melting-point impurities, form a lower eutectic point and eliminate the risk of high-melting-point impurities accumulating and coking in the graphitization furnace. The solvent includes at least one of water, ethanol, methanol, acetone, xylene, dipropylene glycol dimethyl ether, ethylene glycol monomethyl ether and propylene glycol methyl ether. Among them, the performance is best when the liquid composite additive is a calcium chloride aqueous solution, which can be due to the fact that the calcium chloride can blend with high-melting-point impurities in the carbon powder in the graphitization furnace to form a lower eutectic point, eliminate the risk of high-melting-point impurities accumulating and coking in the graphitization furnace, and in addition, the calcium chloride aqueous solution can be matched with polyvinyl alcohol glue powder in the dry powder composite additive to exert good initial bonding effect, and in addition, the calcium chloride can contribute to the enhancement of the particle strength after drying.

[0046] The combination of dry powder composite additive and liquid composite additive can be, but is not limited to, the combination of phenolic resin and urea-formaldehyde resin glue, the combination of phenolic resin and epoxy resin glue, the combination of phenolic resin and phenolic resin glue, the combination of phenolic resin and liquid asphalt glue, the combination of phenolic resin and latex glue, the combination of phenolic resin and water glass, the combination of phenolic resin and calcium chloride solution, the combination of phenolic resin and ferric chloride solution, the combination of phenolic resin and ferrous chloride solution, the combination of modified urea-formaldehyde resin and urea-formaldehyde resin glue, the combination of modified urea-formaldehyde resin and epoxy resin glue, the combination of modified urea-formaldehyde resin and phenolic resin glue, the combination of modified urea-formaldehyde resin and liquid asphalt glue, the combination of modified urea-formaldehyde resin and latex glue, the combination of modified urea-formaldehyde resin and water glass, the combination of modified urea-formaldehyde resin and calcium chloride solution, the combination of modified urea-formaldehyde resin and ferric chloride solution, the combination of modified urea-formaldehyde resin and ferrous chloride solution, the combination of asphalt and urea-formaldehyde resin glue, the combination of asphalt and epoxy resin glue, the combination of asphalt and phenolic resin glue, the combination of asphalt and liquid asphalt glue, the combination of asphalt and latex glue, the combination of asphalt and water glass, the combination of asphalt and calcium chloride solution, the combination of asphalt and ferric chloride solution, the combination of asphalt and ferrous chloride solution, the combination of alpha starch and urea-formaldehyde resin glue, the combination of alpha starch and epoxy resin glue, the combination of alpha starch and phenolic resin glue, the combination of alpha starch and liquid asphalt glue, the combination of alpha starch and latex glue, the combination of alpha starch and water glass, the combination of alpha starch and calcium chloride solution, the combination of alpha starch and ferric chloride solution, the combination of alpha starch and ferrous chloride solution, the combination of redispersible glue powder and urea-formaldehyde resin glue, the combination of redispersible glue powder and epoxy resin glue, the combination of redispersible glue powder and phenolic resin glue, the combination of redispersible glue powder and liquid asphalt glue, the combination of redispersible glue powder and latex glue, the combination of redispersible glue powder and water glass, the combination of redispersible glue powder and calcium chloride solution, the combination of redispersible glue powder and ferric chloride solution, the combination of redispersible glue powder and ferrous chloride solution, the combination of polyvinyl alcohol glue powder and urea-formaldehyde resin glue, the combination of polyvinyl alcohol glue powder and epoxy resin glue, the combination of polyvinyl alcohol glue powder and phenolic resin glue, the combination of polyvinyl alcohol glue powder and liquid asphalt glue, the combination of polyvinyl alcohol glue powder and latex glue, the combination of polyvinyl alcohol glue powder and water glass, the combination of polyvinyl alcohol glue powder and calcium chloride solution, the combination of polyvinyl alcohol glue powder + asphalt powder + redispersible glue powder + hydrochloric acid and calcium chloride solution, the combination of polyvinyl alcohol glue powder + asphalt powder + phenolic resin glue powder + redispersible glue powder + hydrochloric acid and calcium chloride solution, the combination of polyvinyl alcohol glue powder and ferric chloride solution, the combination of polyvinyl alcohol glue powder and ferrous chloride solution, the combination of calcium chloride and urea-formaldehyde resin glue, the combination of calcium chloride and epoxy resin glue, the combination of calcium chloride and phenolic resin glue, the combination of calcium chloride and liquid asphalt glue, the combination of calcium chloride and latex glue, the combination of calcium chloride and water glass, the combination of calcium chloride and calcium chloride solution, the combination of calcium chloride and ferric chloride solution, the combination of calcium chloride and ferrous chloride solution, the combination of phenolic resin, asphalt and urea-formaldehyde resin glue, the combination of phenolic resin, asphalt and epoxy resin glue,Modified urea-formaldehyde resin and liquid asphalt glue, asphalt, re-dispersible glue powder and latex, asphalt, polyvinyl alcohol glue powder and water glass, phenolic resin, asphalt and ferric chloride solution, phenolic resin, phenolic resin glue and latex combination, asphalt and water glass, liquid asphalt glue and calcium chloride solution, liquid asphalt glue and calcium chloride solution, sugar powder, cellulose powder, liquid asphalt glue and calcium chloride solution, etc. As an example, the combination of dry powder composite additive and liquid composite additive can be polyvinyl alcohol glue powder, asphalt powder, re-dispersible glue powder, hydrochloric acid and calcium chloride solution, or polyvinyl alcohol glue powder, asphalt powder, phenolic resin glue powder, re-dispersible glue powder, hydrochloric acid and calcium chloride solution.

[0047] The mixed material is first buffered and then pressed into a ball in a ball press to obtain carbon balls with a particle size of 5mm to 35mm. The particle size of the carbon balls can be, but is not limited to, 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm. The mixed material is tempered and buffered. The pressure during tempering is controlled to be -0.001kPa to -30.0kPa, the tempering time is 1min to 30min, and the tempering time should not be too long, otherwise the liquid will volatilize and the material will dry, affecting the quality of the ball. Tempering under slight negative pressure is beneficial to the full contact of the additive with the carbon powder, the discharge of gas in the pores of the carbon powder, and the improvement of the density of the ball. The tempered material is sent to the ball press for ball pressing. The pressure for ball pressing is 0.5MPa to 5.0MPa, and the continuous pressing method without pressure holding is adopted. The free-fall breakage resistance value of the pressed carbon ball is 300mm to 800mm. The determination method of the free-fall breakage resistance value can be as follows.

[0048] (1) Place the test fixture, which consists of a base, a support rod, and a particle placement rack. The base is a steel plate with dimensions of 10mm thick x 100mm x 100mm. The support rod is a steel pipe with a diameter of 8mm and a length of 1500mm. The steel pipe is connected vertically to the steel plate through threads, and the steel pipe has a scale marked from 0mm to 1300mm on the upper surface. The particle placement rack has a particle placement ring with a horizontally movable holder at the bottom. The particle placement ring can move up and down on the support rod and is fixed by screws.

[0049] (2) Place the particles, fix the particle placement ring to the selected height, and tighten. Place the holder directly below the particle placement ring, and then place the complete particles into the particle placement ring and on the holder.

[0050] (3) Free-fall operation, move the holder to the left or right, and the particles on the holder fall freely and hit the upper surface of the base.

[0051] (4) Check the state of the free-falling particles to evaluate the free-falling particle anti-crushing strength value. In each low-limit height test, the free-falling particles are complete and not crushed, and in each high-limit height + 1 mm test, the free-falling particles are not complete and are crushed, which is qualified. For example, the free-falling anti-crushing strength value of 300 mm is that the carbon balls are pressed at 300 mm, then allowed to free fall, and then observed for crushing. If not crushed, it indicates that the anti-crushing strength value is at least 300 mm, and if crushed, it indicates that the anti-crushing strength value is at most 300 mm.

[0052] Step (three) includes baking the carbon balls in a continuous gradient drying oven and then performing vertical continuous carbonization graphitization to obtain graphitized particles with a free-falling anti-crushing strength value of 150 mm to 450 mm, and then performing post-processing. The carbon balls are first dried at a gradient of 30°C to 105°C, then baked at a gradient of 105°C to 300°C to a water content of 0.01 wt.% or less, and then carbonized and graphitized. The baking cannot be raised to above 200°C at one time, otherwise the rapid heating is not conducive to obtaining good apparent indicators of the product. The baking time is 30 min to 90 min, which can be but is not limited to 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, or 90 min. Baking can melt and consolidate the thermosetting components and hot-melt components in the carbon balls, which is conducive to the formation of a stable structure of the particles, maintains good mechanical strength, and improves the stability and safety of subsequent graphitization. After baking, the free-falling anti-crushing strength value of the carbon balls is increased to 400 mm to 1300 mm. Continuous baking of the carbon balls compared to intermittent baking can shorten the production cycle, improve production efficiency, and improve thermal energy utilization.

[0053] The pre-carbonization process is further included between the baking and graphitization, and the baking, pre-carbonization and graphitization equipment is integrated. The integrated baking, pre-carbonization and graphitization can greatly reduce the heat loss and ensure the strength and integrity of the particles, and avoid damage or pulverization caused by intermittent operation. The integrated baking, pre-carbonization and graphitization equipment can be an integrated machine integrating the baking, pre-carbonization and graphitization functions in sequence, or the outlets and inlets of the baking machine, pre-carbonization machine and graphitization machine can be sequentially connected to avoid the loss caused by the transfer of materials. The baking machine and pre-carbonization machine can use conventional machines, and the graphitization machine can use a conventional vertical continuous graphitization machine, which only needs to meet the integrated requirement. The integrated and continuous pre-carbonization and graphitization process can realize a self-oxygen isolation system with a slight positive pressure at the top of the furnace by using the volatile gas generated in the pre-carbonization process and the gas overflowed during the graphitization purification, without the need to introduce a large amount of inert gas for oxygen isolation protection, which can reduce the equipment investment and operating cost, especially avoiding the introduction of a large amount of N2 and the investment and operating cost of denitration. The pre-carbonization temperature is 500-2200°C, which can be but is not limited to 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1400°C, 1500°C, 1600°C, 1700°C, 1800°C, 1900°C, 2000°C, 2100°C, 2200°C. The pre-carbonization time is 2-20h, which can be but is not limited to 2h, 4h, 10h, 14h, 15h, 16h, 18h, 20h. The pre-carbonization process is carried out under the condition that the slight differential pressure of the overflow gas is controlled to be 0Pa to +25Pa, without the need for inert gas protection. The vertical continuous graphitization is carried out under the condition that the slight differential pressure of the overflow gas is controlled to be 0Pa to +25Pa, and the graphitization discharge area is discharged under the condition of mechanical closed gas oxygen isolation. The free-fall anti-crushing strength value of the carbonized carbon sphere is 350-700mm.

[0054] The vertical continuous graphitization temperature is 2200-3300°C, which can be but is not limited to 2200°C, 2300°C, 2400°C, 2500°C, 2600°C, 2700°C, 2800°C, 2900°C, 3000°C, 3100°C, 3200°C, 3300°C. The vertical continuous graphitization time is 6-36h, which can be but is not limited to 6h, 10h, 13h, 16h, 20h, 24h, 28h, 32h, 36h. The vertical continuous graphitization is carried out under the condition that the slight differential pressure of the overflow gas is controlled to be 0Pa to +25Pa, and the discharge area adopts the mechanical closed gas oxygen isolation condition, without the need for inert gas protection. The power of the vertical continuous graphitization is 400-2700KW, which can be but is not limited to 400KW, 800KW, 1200KW, 1600KW, 2000KW, 2300KW, 2700KW.

[0055] The post-processing includes dispersing and classifying to a particle size of 5-30 μm, for example, the particle size can be, but is not limited to, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm. By dispersing the graphitized powder, the problem of poor product quality caused by the need for crushing and grinding of the graphitized particles obtained by the existing vertical graphitization process, over-grinding and over-milling can be avoided. There is no crushing or grinding action so as to effectively protect the sphericity, morphology, stable specific surface area and tap density of the product, and iron is not introduced, and further magnetic removal is not needed at the back end of the process. In order to better illustrate the purpose, technical scheme and beneficial effects of the present application, the present application will be further described below in conjunction with specific embodiments. It should be noted that the following implementation of the method is a further explanation and description of the present application, and should not be regarded as a limitation of the present application.

[0056] Example 1

[0057] The process for continuous graphitization of a negative electrode material includes the following steps.

[0058] (I) The petroleum calcined coke is mixed and then continuously and automatically fed into a crusher for crushing to carbon source particles with a maximum particle size of 5 mm. The carbon source particles are directly and continuously fed into a grinding and granulating machine for grinding to obtain carbon micropowder with a particle size of 15 μm, a tap density of 0.853 g / cm 3 , and a smooth surface.

[0059] (II) The carbon micropowder, phenolic resin (particle size of 20.00 μm), pitch powder and polyvinyl alcohol glue powder are mixed in a screw mixer at a mass ratio of 100:1:1:1, then 2 mol of hydrochloric acid and calcium chloride solution are sprayed (the mass ratio of carbon micropowder and 50 wt.% calcium chloride solution is 100:22, and the amount of hydrochloric acid is such that the pH value of the carbon micropowder mixture is 6.5), and the mixture is uniformly mixed and then fed into a buffer bin for steaming and buffering. The pressure in the buffer bin is -30.0 Pa, and the steaming time is 3 min. The steamed material is fed into a ball press for ball pressing to obtain carbon balls with a particle size of 20 mm. The free-fall breakage resistance of the carbon balls is tested, and the free-fall breakage resistance value is 370 mm.

[0060] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ baking, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, 3 h of 1500 ℃ heat preservation, and 6 h of 2100 ℃ pre-carbonization, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.867 g / cm 3 , the running powder loss rate is 2.1 wt.%, and the free-fall anti-crushing strength value of the graphitized particles is 401 mm. The prepared negative electrode material is detected by SEM, and the results are shown in FIG. 1, which shows that the surface roundness of the negative electrode material prepared in this embodiment is good, the product impurity content is 0.001 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0061] Example 2

[0062] This embodiment is a process for continuous graphitization production of a negative electrode material, which includes the following steps.

[0063] (One) petroleum green oil coke is mixed and continuously automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly continuously fed into a grinding granulator to be ground into carbon micropowder with a particle size of 22 μm and a tap density of 0.853 g / cm 3 , and the carbon micropowder has a smooth surface.

[0064] (Two) carbon micropowder, phenolic resin (particle size 20.00 μm), pitch powder, polyvinyl alcohol glue powder and redispersible glue powder are mixed in a screw mixer at a mass ratio of 100:1:1:1:0.4, and then 2 mol of hydrochloric acid and calcium chloride solution (the mass ratio of carbon micropowder and 50 wt.% calcium chloride solution is 100:20, and the amount of hydrochloric acid is such that the pH value of the carbon micropowder mixture is 6.7) is sprayed, and after mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa, and the steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon spheres with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon spheres is 415 mm after free-fall anti-crushing strength test.

[0065] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, and then 6 h of 2100 ℃ pre-carbonization, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.868 g / cm 3 , the running powder loss rate is 1.9 wt.%, and the free-fall anti-crushing strength value of the graphitized particles is 405 mm. The prepared negative electrode material is detected by SEM, and the results are shown in FIG. 2, which shows that the surface roundness of the negative electrode material prepared in this embodiment is good, the product impurity content is 0.001 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0066] Example 3

[0067] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0068] (One) After the petroleum calcined coke is mixed and continuously automatically fed into a pulverizer, the carbon source particles with a maximum particle size of 5 mm are obtained, and the carbon source particles are directly continuously fed into a grinding granulator to obtain carbon micropowder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 , and the surface of the carbon micropowder is round.

[0069] (Two) The carbon micropowder, phenolic resin (particle size 20.00 μm) and calcium chloride powder are mixed in a screw mixer at a mass ratio of 100:1:3, and then 2 mol of hydrochloric acid and water-based liquid pitch glue are sprayed (the mass ratio of carbon micropowder and solid content 10% liquid pitch glue is 100:22, and the amount of hydrochloric acid is such that the pH value of the carbon micropowder mixture is 6.3), and after mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa, and the steaming time is 3 min, and the steamed material is fed into a ball press to obtain carbon spheres with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon spheres is 355 mm.

[0070] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, 3 h of 1500 ℃ heat preservation, and 6 h of 2100 ℃ pre-carbonization, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace with a power of 610 KW. After graphitization, the material is scattered, graded and the negative electrode material with a particle size of 20 μm is obtained. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.867 g / cm 3 , the running powder loss rate is 1.5 wt.%, and the free-fall anti-crushing strength value of the graphitized particles is 419 mm. The prepared negative electrode material is detected by SEM, and the results are shown in FIG. 3, which shows that the surface roundness of the negative electrode material prepared in this embodiment is good, the product impurity content is 0.002 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0071] Example 4

[0072] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0073] (One) petroleum calcined coke is mixed and continuously automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly continuously fed into a grinding granulator to be ground into carbon micropowder with a particle size of 15 μm and a tap density of 0.827 g / cm 3 , and the carbon micropowder has a smooth surface.

[0074] (Two) carbon micropowder, phenolic resin (particle size of 20 μm), calcium chloride powder (particle size of 90 μm) and latex powder (particle size of 80 μm) are mixed in a screw mixer at a mass ratio of 100:2:3:0.5, then 2 mol of hydrochloric acid and emulsified liquid asphalt glue with a solid content of 10% (the mass ratio of carbon micropowder and liquid asphalt glue is 100:21, and the amount of hydrochloric acid is such that the pH value of the carbon micropowder mixture is 6.5) are sprayed, and after mixing, the material is fed into a buffer bin for steaming and buffering, the pressure in the buffer bin is -30.0 Pa, the steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon spheres with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon spheres is 365 mm.

[0075] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, and then 6 h of 2100 ℃ pre-carbonization, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.839 g / cm 3 , the running powder loss rate is 1.1 wt.%, and the free-fall anti-crushing strength value of the graphitized particles is 443 mm. The prepared negative electrode material is detected by SEM, and the results are shown in Figure 4, which shows that the surface roundness of the negative electrode material prepared in this embodiment is good, the product impurity content is 0.002 wt.%, and there is no coking and hardening phenomenon in the graphitization furnace.

[0076] Example 5

[0077] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0078] (One) After mixing, the petroleum calcined coke is continuously and automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly and continuously fed into a grinding granulator to be ground into carbon micropowder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 , and the surface of the carbon micropowder is round.

[0079] (Two) The carbon micropowder, phenolic resin (particle size 20 μm) and calcium chloride powder (particle size 90 μm) are mixed in a screw mixer at a mass ratio of 100:2:3, and then 15% emulsified liquid asphalt glue is sprayed (the mass ratio of carbon micropowder to emulsified liquid asphalt glue is 100:23), and after mixing, the material is fed into a buffer bin for tempering and buffering, and the pressure in the buffer bin is -30.0 Pa, and the tempering time is 3 min. The tempered material is fed into a ball press to be pressed into carbon spheres with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon spheres is 369 mm.

[0080] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, 6 h of 2100 ℃ pre-carbonization, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered and graded to a particle size of 20 μm negative electrode material. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.1 wt.%, the tap density is 0.867 g / cm 3 , the running powder loss rate is 0.7 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 447 mm, the impurity content is 0.022 wt.%, and no coking and hardening occurs in the graphitization furnace.

[0081] Example 6

[0082] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0083] (One) petroleum calcined coke is mixed and continuously automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly continuously fed into a grinding granulator to be ground into carbon micro-powder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 , and the carbon micro-powder has a smooth surface.

[0084] (Two) carbon micro-powder, phenolic resin (particle size 55 μm), and aluminum phosphate powder (particle size 90 μm) are mixed in a screw mixer at a mass ratio of 100:2:3, then 2 mol of phosphoric acid solution and 15% solid content emulsified liquid asphalt glue (mass ratio of carbon micro-powder and liquid asphalt glue is 100:21, and the amount of phosphoric acid added is such that the PH value of the carbon micro-powder mixture is 6.7) are sprayed, and after mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa, the steaming time is 3 min, the steamed material is fed into a ball press to be pressed into carbon balls with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon balls is 360 mm after free-fall anti-crushing strength test.

[0085] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, 6 h of 2100 ℃ pre-carbonization, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, classified and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.1 wt.%, the tap density is 0.865 g / cm 3 , the running powder loss rate is 0.9 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 443 mm, the product impurity content is 0.002 wt.%, and there is no coking and hardening phenomenon in the graphitization furnace.

[0086] Example 7

[0087] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0088] (One) petroleum calcined coke is mixed and continuously automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly continuously fed into a grinding granulator to be ground into carbon micro powder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 , and the carbon micro powder has a smooth surface.

[0089] (Two) carbon micro powder, corn starch (particle size 80 μm) and calcium chloride powder (particle size 80 μm) are mixed in a screw mixer at a mass ratio of 100:2:3, then 2 mol of hydrochloric acid solution and 10% solid content emulsified liquid asphalt glue (mass ratio of carbon micro powder and liquid asphalt glue is 100:21) are sprayed, and the amount of hydrochloric acid added is such that the pH value of the carbon micro powder mixture is 6.7. After mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa. The steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon balls with a particle size of 20 mm. The free-fall anti-crushing strength value of the carbon balls is 390 mm through free-fall anti-crushing strength test.

[0090] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, and then 6 h of 2100 ℃ pre-carbonization in the protection of volatilized overflow gas, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.862 g / cm 3 , the running powder loss rate is 1.9 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 404 mm, the product impurity content is 0.001 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0091] Example 8

[0092] The embodiment is a process for continuous graphitization production of a negative electrode material, which comprises the following steps.

[0093] (One) petroleum calcined coke is continuously and automatically fed into a pulverizer after mixing to be crushed into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly and continuously fed into a grinding granulator to be ground into carbon micropowder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 .

[0094] (Two) carbon micropowder, polyvinyl alcohol glue powder (particle size of 20 μm), redispersible glue powder (particle size of 80 μm), and calcium chloride powder (particle size of 100 μm) are mixed in a screw mixer at a mass ratio of 100:1:0.5:3, and then 2 mol of hydrochloric acid solution and an emulsified liquid asphalt glue with a solid content of 15% (the mass ratio of carbon micropowder and liquid asphalt glue is 100:20, and the amount of added hydrochloric acid is such that the pH value of the carbon micropowder mixture is 6.9) are sprayed, and after mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa, and the steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon balls with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon balls is 405 mm after a free-fall anti-crushing strength test.

[0095] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, and then 6 h of 2100 ℃ pre-carbonization under the protection of volatilized overflow gas, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the negative electrode material with a particle size of 20 μm is obtained. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.867 g / cm 3 , the running powder loss rate is 1.8 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 415 mm, the product impurity content is 0.001 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0096] Example 9

[0097] The embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0098] (One) petroleum calcined coke is mixed and continuously automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly continuously fed into a grinding granulator to be ground into carbon micro-powder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 .

[0099] (Two) carbon micro-powder, calcium chloride powder (particle size of 90 μm) and polyvinyl alcohol powder (particle size of 80 μm) are mixed in a screw mixer at a mass ratio of 100:3:1, then 2 mol of hydrochloric acid solution and emulsified liquid pitch glue (mass ratio of carbon micro-powder and solid content of 15% liquid pitch glue is 100:20, and the amount of hydrochloric acid added is such that the pH value of the carbon micro-powder mixture is 6.9) are sprayed, and after mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa, the steaming time is 3 min, the steamed material is fed into a ball press to be pressed into carbon balls with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon balls is 390 mm through free-fall anti-crushing strength test.

[0100] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, and then 6 h of 2100 ℃ pre-carbonization, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.865 g / cm 3 , the running powder loss rate is 1.9 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 449 mm, the product impurity content is 0.001 wt.%, and no coking and hardening occurs in the graphitization furnace.

[0101] Example 10

[0102] The embodiment is a process for continuous graphitization production of a negative electrode material, which comprises the following steps.

[0103] (One) petroleum calcined coke is mixed and continuously automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly continuously fed into a grinding granulator to be ground into carbon micropowder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 .

[0104] (Two) carbon micropowder and phenolic resin (particle size 20 μm) + asphalt powder (particle size 20 μm) + cassava powder (particle size 80 μm) + redispersible glue powder (particle size 80 μm) are mixed in a spiral ribbon mixer at a mass ratio of 100:1:2:0.5:0.5, then 2 mol of hydrochloric acid solution and 25% calcium chloride solution (mass ratio of carbon micropowder and calcium chloride solution is 100:20, and the amount of hydrochloric acid added is such that the PH value of the carbon micropowder mixture is 6.7) are sprayed, and after mixing, the material is fed into a buffer bin for steaming and buffering, the pressure in the buffer bin is -30.0 Pa, the steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon balls with a particle size of 20 mm, which are tested by free-fall anti-crushing strength, and the free-fall anti-crushing strength value is 395 mm.

[0105] (Three) carbon balls are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, 0.5 h of heat preservation at 45℃, then 0.5 h of drying at 85℃ after heating, 0.5 h of heat preservation at 150℃, then 2.0 h of baking at 280℃ after heating, until the water content is 0.01 wt.%, then pre-carbonization at 1500℃ for 3 h after heating and 2100℃ for 6 h under the protection of volatilized overflow gas, and graphitization at 3000℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.866 g / cm 3 , the running powder loss rate is 2.0 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 405 mm, the product impurity content is 0.001 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0106] Example 11

[0107] This embodiment is a process for continuous graphitization production of negative electrode material, which includes the following steps.

[0108] (One) Petroleum calcined coke is continuously and automatically fed into a pulverizer after mixing to be crushed into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly and continuously fed into a grinding granulator to be ground into carbon micropowder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 , and the carbon micropowder has a smooth surface.

[0109] (Two) Carbon micropowder, phenolic resin (particle size 20 μm), pitch powder (particle size 20 μm), polyvinyl alcohol glue powder (particle size 80 μm) and redispersible glue powder (particle size 80 μm) are mixed in a screw mixer at a mass ratio of 100:1:2:1:0.5, then sprayed with 1 mol sulfuric acid and 20% calcium chloride solution (mass ratio of carbon micropowder and calcium chloride solution is 100:20, and the amount of sulfuric acid added is such that the pH value of the carbon micropowder mixture is 6.7), and after mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa, and the steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon balls with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon balls is 425 mm 3 after free-fall anti-crushing strength test.

[0110] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, and then 6 h of 2100 ℃ pre-carbonization in the protection of volatilized overflow gas, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.865 g / cm 3 , the running powder loss rate is 1.8 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 417 mm, the product impurity content is 0.003 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0111] Example 12

[0112] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0113] (One) petroleum calcined coke is continuously and automatically fed into a pulverizer after mixing to be crushed into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly and continuously fed into a grinding granulator to be ground into carbon micro powder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 , and the carbon micro powder has a smooth surface.

[0114] (Two) carbon micro powder + phenolic resin (particle size 20.00 μm) + cellulose powder (particle size 80 μm) + polyvinyl alcohol powder (particle size 80.00 μm) are mixed in a screw mixer at a mass ratio of 100:0.5:0.5:0.5, then sprayed with 2 mol hydrochloric acid and emulsified liquid asphalt glue with a solid content of 12.5% (the mass ratio of carbon micro powder and liquid asphalt glue is 100:20, and the amount of hydrochloric acid added is such that the PH value of the carbon micro powder mixture is 6.6), and after mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa, the steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon balls with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon balls is 393 mm after free-fall anti-crushing strength test.

[0115] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, and then 6 h of 2100 ℃ pre-carbonization under the protection of volatilized overflow gas, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered and graded to a particle size of 20 μm negative electrode material. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.866 g / cm 3 , the running powder loss rate is 1.9 wt.%, the free fall anti-crushing strength value of the graphitized particles is 407 mm, the product impurity content is 0.001 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0116] Example 13

[0117] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0118] (One) petroleum calcined coke is mixed and continuously automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly continuously fed into a grinding granulator to be ground into carbon micro powder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 .

[0119] (Two) carbon micro powder, phenolic resin (particle size 20.00 μm) and polyvinyl alcohol glue powder (particle size 80.00 μm) are mixed in a screw mixer at a mass ratio of 100:1:0.5, then 2 mol of hydrochloric acid and 10% solid content emulsified liquid asphalt glue (mass ratio of carbon micro powder and liquid asphalt glue is 100:20) are sprayed, and the mixture is mixed uniformly. After that, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa. The steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon balls with a particle size of 20 mm. The free fall anti-crushing strength value of the carbon balls is 320 mm through free fall anti-crushing strength test.

[0120] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ drying, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, and 3 h of 1500 ℃ heat preservation, and then 6 h of 2100 ℃ pre-carbonization under the protection of volatilized overflow gas, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the negative electrode material with a particle size of 20 μm is obtained. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.865 g / cm 3 , the running powder loss rate is 2.0 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 403 mm, the product impurity content is 0.002 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0121] Example 14

[0122] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0123] (One) petroleum calcined coke is mixed and then continuously and automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly and continuously fed into a grinding granulator to be ground into carbon micro-powder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 , and the carbon micro-powder has a smooth surface.

[0124] (Two) carbon micro-powder, phenolic resin, redispersible glue powder and calcium chloride powder (dry powder composite additive with a particle size of 5-90 μm) are mixed in a screw mixer at a mass ratio of 100:0.5:0.5:3, then 2 mol of hydrochloric acid and 20% emulsified liquid asphalt glue (the mass ratio of carbon micro-powder and liquid asphalt glue is 100:20, and the amount of hydrochloric acid added is such that the pH value of the carbon micro-powder mixture is 6.3) are sprayed, and after mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa, the steaming time is 3 min, the steamed material is fed into a ball press to be pressed into carbon spheres with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon spheres is 323 mm after free-fall anti-crushing strength test.

[0125] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 °C heat preservation, 0.5 h of 85 °C drying, 0.5 h of 150 °C heat preservation, 2.0 h of 280 °C baking to 0.01 wt.% water content, and 3 h of 1500 °C heat preservation, and then 6 h of 2100 °C pre-carbonization, the material is graphitized at 3000 °C for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is dispersed and classified to a particle size of 20 μm negative electrode material. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.867 g / cm 3 , the running powder loss rate is 1.0 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 448 mm, the product impurity content is 0.001 wt.%, and no coking and hardening occurs in the graphitization furnace.

[0126] Example 15

[0127] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0128] (One) Petroleum calcined coke is mixed and then continuously and automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 4.5 mm. The carbon source particles are directly and continuously fed into a grinding granulator to be ground into carbon micro-powder with a particle size of 10 μm and a tap density of 0.103 g / cm, and the carbon micro-powder has a round surface.

[0129] (Two) Carbon micro-powder, pitch powder, polyvinyl alcohol powder, redispersible glue powder and calcium chloride powder are mixed in a screw mixer at a mass ratio of 100:3:1:0.5:3, and then 2 mol of hydrochloric acid and water are sprayed (the mass ratio of carbon micro-powder to water is 70:20, and the amount of hydrochloric acid added is such that the pH value of the carbon micro-powder mixture is 6.8). After mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa. The steaming time is 5 min, and the steamed material is fed into a ball press to be pressed into carbon spheres with a particle size of 15 mm. The free-fall anti-crushing strength value of the carbon spheres is 330 mm through free-fall anti-crushing strength test.

[0130] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 ℃ heat preservation, 0.5 h of 85 ℃ baking, 0.5 h of 150 ℃ heat preservation, 2.0 h of 280 ℃ baking to 0.01 wt.% water content, 3 h of 1500 ℃ heat preservation, and 6 h of 2100 ℃ pre-carbonization, the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.866 g / cm 3 , the running powder loss rate is 1.8 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 416 mm, the product impurity content is 0.001 wt.%, and no coking and hardening occurs in the graphitization furnace.

[0131] Example 16

[0132] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0133] (One) petroleum calcined coke is mixed and continuously automatically fed into a pulverizer to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly continuously fed into a grinding granulator to be ground into carbon micro-powder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 .

[0134] (Two) carbon micro-powder, pitch powder, polyvinyl alcohol powder, redispersible glue powder and calcium chloride powder are mixed in a screw mixer at a mass ratio of 100:1.5:1:0.5:3, and hydrochloric acid solution and water are sprayed (the mass ratio of carbon micro-powder and water is 100:20, and the amount of 2 mol hydrochloric acid solution added is such that the pH value of the carbon micro-powder mixture is 6.8), and after mixing, the material is fed into a buffer bin for steaming and buffering, and the pressure in the buffer bin is -30.0 Pa, and the steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon spheres with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon spheres is 375 mm through free-fall anti-crushing strength test.

[0135] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 °C heat preservation, 0.5 h of 85 °C drying, 0.5 h of 150 °C heat preservation, 2.0 h of 280 °C baking to 0.01 wt.% water content, and 3 h of 1500 °C heat preservation, the material is pre-carbonized at 2100 °C for 6 h, and then graphitized at 3000 °C for 8 h in a vertical continuous graphitization furnace. The power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, classified and the particle size of the negative electrode material is 15 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.862 g / cm 3 , the running powder loss rate is 2.1 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 397 mm, the product impurity content is 0.001 wt.%, and no coking and hardening occurs in the graphitization furnace.

[0136] Example 17

[0137] This embodiment is a process for continuous graphitization production of negative electrode material, which comprises the following steps.

[0138] (One) petroleum calcined coke is continuously and automatically fed into a pulverizer after mixing to be crushed into carbon source particles with a maximum particle size of 5 mm. The carbon source particles are directly and continuously fed into a grinding granulator to be ground into carbon micropowder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 , and the surface of the carbon micropowder is smooth.

[0139] (Two) carbon micropowder, phenolic resin (particle size 20 μm), pitch powder (particle size 10 μm), and polyvinyl alcohol powder (particle size 80 μm) are mixed in a screw mixer at a mass ratio of 100:1:1:1, and then 2 mol of hydrochloric acid solution and calcium chloride solution are sprayed (the mass ratio of carbon micropowder and 50 wt.% calcium chloride solution is 100:22, and the amount of 2 mol of hydrochloric acid solution added is such that the pH value of the carbon micropowder mixture is 6.5). After mixing, the material is fed into a buffer bin for steaming and buffering. The pressure in the buffer bin is -30.0 Pa, and the steaming time is 3 min. The steamed material is fed into a ball press to be pressed into carbon spheres with a particle size of 20 mm. The free-fall anti-crushing strength value of the carbon spheres is 370 mm after the free-fall anti-crushing strength test.

[0140] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, dried at 85°C for 1.0 h, baked at 280°C for 2.0 h to have a water content of 0.01 wt.%, pre-carbonized at 1500°C for 3 h and then at 2100°C for 6 h under the protection of volatilized overflow gas, and graphitized at 3000°C for 8 h in a vertical continuous graphitization furnace with a power of 610 KW. After graphitization, the material is scattered, graded and the negative electrode material with a particle size of 20 μm is obtained. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 2.0 wt.%, the tap density is 0.866 g / cm 3 , the running powder loss rate is 1.9 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 415 mm, the product impurity content is 0.002 wt.%, and no coking and hardening phenomenon occurs in the graphitization furnace.

[0141] Comparative Example 1

[0142] The embodiment is a process for continuous graphitization production of a negative electrode material, which comprises the following steps.

[0143] (One) petroleum calcined coke is continuously and automatically fed into a pulverizer after mixing to be pulverized into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly and continuously fed into a grinding granulator to be ground into carbon micropowder with a particle size of 15 μm and a tap density of 0.853 g / cm 3 , and the carbon micropowder has a smooth surface.

[0144] (Two) carbon micropowder + α cassava powder (particle size of 80 μm) + phenolic resin powder (particle size of 90 μm) are mixed in a screw belt mixer at a mass ratio of 100:6:3, sprayed with liquid PVA glue (mass ratio of carbon micropowder and 10% liquid PVA glue is 100:23) in the screw belt mixer, mixed uniformly, and then fed into a buffer bin for steaming and buffering. The pressure in the buffer bin is -30.0 Pa, the steaming time is 3 min, and the steamed material is fed into a ball press to be pressed into carbon spheres with a particle size of 20 mm. The free-fall anti-crushing strength value of the carbon spheres is 720 mm through free-fall anti-crushing strength test.

[0145] (Three) carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of 45 °C heat preservation, 0.5 h of 85 °C drying, 0.5 h of 150 °C heat preservation, 2.0 h of 280 °C baking to 0.01 wt.% water content, and 3 h of 1500 °C heat preservation, and then 6 h of 2100 °C pre-carbonization, the material is graphitized at 3000 °C for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is crushed, ground, and classified to a particle size of 20 μm to obtain a negative electrode material. The prepared negative electrode material product is detected and calculated, the low-value byproduct accounts for 7.5 wt.%, the tap density is 0.845 g / cm 3 , the running powder loss rate is 1.0 wt.%, and the free-fall anti-crushing strength value of the graphitized particles is 597 mm. The prepared negative electrode material is detected by SEM, and the results are shown in Figure 5, which shows that the surface of the negative electrode material prepared in the present comparative example is rough, not smooth, and has many pits and grooves, the product impurity content is 0.031 wt.%, and the coking phenomenon occurs in the graphitization furnace.

[0146] Comparative Example 2

[0147] The present comparative example is a process for continuous graphitization production of a negative electrode material, which comprises the following steps.

[0148] (One) petroleum calcined coke is mixed and then continuously and automatically fed into a crusher to be crushed into carbon source particles with a maximum particle size of 5 mm, and the carbon source particles are directly and continuously fed into a grinding granulator to be ground into carbon micropowder with a particle size of 15 μm, a tap density of 0.853 g / cm 3 , and a smooth surface.

[0149] (Two) the carbon micropowder, phenolic resin (particle size 20.00 μm), alpha corn starch and water are mixed in a screw conveyor mixer in a mass ratio of 100:1:5:23, and after dry mixing, the mixture is wet mixed by spraying water, and after mixing, the material is fed into a buffer bin for material soaking and buffering, and the pressure in the buffer bin is -30.0 Pa, and the soaking time is 3 min, and the soaked material is fed into a ball press to be pressed into carbon spheres with a particle size of 20 mm, and the free-fall anti-crushing strength value of the carbon spheres is 490 mm.

[0150] (III) The carbon spheres are sequentially baked, pre-carbonized and graphitized by using an integrated baking-pre-carbonization-graphitization machine, and after 0.5 h of heat preservation at 45 ℃, the temperature is raised to 85 ℃ for 0.5 h of baking, then after 0.5 h of heat preservation at 150 ℃, the temperature is raised to 280 ℃ for 2.0 h of baking until the water content is 0.01 wt.%, then under the protection of volatilized overflow gas, the temperature is raised to 1500 ℃ for 3 h of heat preservation, and then the temperature is raised to 2100 ℃ for 6 h of pre-carbonization, and then the material is graphitized at 3000 ℃ for 8 h in a vertical continuous graphitization furnace, and the power of the vertical continuous graphitization furnace is 610 KW. After graphitization, the material is scattered, graded and the particle size of the negative electrode material is 20 μm. The prepared negative electrode material product is detected and calculated, the low-value byproduct ratio is 1.9 wt.%, the tap density is 0.851 g / cm 3 , the running powder loss rate is 16.5 wt.%, the free-fall anti-crushing strength value of the graphitized particles is 109 mm, the product impurity content is 0.033 wt.%, and the coking and hardening phenomenon occurs in the graphitization furnace.

[0151] Table 1 Properties of artificial graphite obtained by application examples 1 to 17 and comparative examples 1 to 2

[0152] Among them, * indicates that the particle strength after graphitization is too high, and the byproduct ratio is high due to crushing and grinding; ** indicates that the particle strength after graphitization is too low, and the running powder loss rate is high during graphitization.

[0153] It can be known from examples 1 to 17 of the present application that the addition of an appropriate amount of hydrochloric acid, phosphoric acid and sulfuric acid in the additive has a good effect on reducing the impurity content of the product, and the addition of calcium chloride and aluminum phosphate has a positive contribution to avoiding the enrichment and coking of high-melting-point impurities in the graphitization furnace.

[0154] It can be known from examples 8 and 9 of the present application that the addition of an appropriate amount of redispersible glue powder in the additive has certain water-reducing property, which can improve the particle strength and reduce the running powder rate.

[0155] It can be known from examples 1 to 17 and comparative examples 1 to 2 of the present application that the production process of the present application not only can ensure continuous production, but also can control the low-value byproduct ratio of the prepared negative electrode material to be less than 2.3 wt.%, and the tap density is 0.861 g / cm 3The run-off loss rate is 2.3 wt.% or less. This is because, in the production process of the present application, the carbon spheres with a free-fall breakage resistance value of 300 mm to 800 mm are prepared by adding additives for pressing when the carbon spheres are prepared, and the free-fall breakage resistance value of the particles after graphitization is 150 mm to 450 mm. Controlling the free-fall breakage resistance value of the carbon spheres to a certain range can not only ensure that the carbon spheres are not easily washed off even when they are affected by the overflow gas in the vertical continuous graphitization equipment, and the run-off loss rate is low, but also avoid the problem of excessive strength that causes the material surface to be rough and the tap density to be small during subsequent processing.

[0156] As can be seen from Comparative Examples 1 to 2, the free-fall breakage resistance value of the particles after graphitization is higher than 450 mm, and the by-products are more and the product quality is poor. If the free-fall breakage resistance value of the particles after graphitization is lower than 150 mm, the run-off loss during graphitization is large. In addition, the initial strength obtained by balling the α cassava powder is high, but the strength after carbonization and graphitization is low.

[0157] As can be seen from Examples 15 to 16 of the present application, the finer the carbon micro powder, the more solvent is required to be added. This is because the specific surface area of the carbon micro powder is larger.

[0158] As can be seen from Comparative Example 1 and Example 17, baking using gradient heating can improve the performance of the negative electrode material. This may be because the dry powder composite additive is fully coked and solidified in the carbon micro powder particles after heat melting by step baking, which improves the strength of the particles, and also avoids the problem of carbon micro powder particle brittleness caused by rapid heating and baking, which ensures that the carbon micro powder particles will not be broken and pulverized during the subsequent pre-carbonization process.

[0159] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, it is not limited to the embodiments listed. Those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A process for the continuous graphitization production of an anode material, characterized in that, The application relates to a method for preparing a carbon particle with a free-fall anti-crushing strength value of 150mm to 450mm. The method comprises the following steps: (1) performing pretreatment on a carbon source to obtain carbon micro-powder; (2) mixing the carbon micro-powder and an additive to obtain a carbon ball with a free-fall anti-crushing strength value of 300mm to 800mm after compression; 2. The process for the continuous graphitization production of an anode material according to claim 1, characterized in that, (3) performing continuous gradient drying and baking on the carbon ball, and then performing vertical continuous carbonization and graphitization to obtain the carbon particle with the free-fall anti-crushing strength value of 150mm to 450mm, and then performing post-treatment.

3. The process for the continuous graphitization production of an anode material according to claim 2, characterized in that, The additive comprises dry powder composite additive and liquid composite additive. At least one of the following features (I) to (IV) is included: (I) the mass ratio of the carbon micro-powder to the dry powder composite additive is 50 to 100:0.5 to 10.

00. (II) the average particle size of the dry powder composite additive is 0.01mu to 100.00mu. (III) the mass ratio of the carbon micro-powder to the liquid composite additive is 50 to 100:6 to 25.

4. The process for the continuous graphitization production of a negative material according to claim 2, characterized by the fact that, (IV) the dry powder composite additive is mixed first, and then the liquid composite additive is mixed.

5. The process for the continuous graphitization production of an anode material according to claim 4, characterized in that, The dry powder composite additive comprises at least two of resin powder, glue powder and inorganic salt powder.

6. The process for the continuous graphitization production of a negative material according to claim 2, characterized in that, The resin powder comprises at least one of phenolic resin, modified urea-formaldehyde resin and pitch, the glue powder comprises at least one of redispersible glue powder, cellulose powder, alpha starch, polyvinyl alcohol glue powder and latex powder, and the inorganic salt powder comprises at least one of sodium silicate, calcium chloride, ferric chloride, ferrous chloride and aluminum phosphate.

7. The process for the continuous graphitization production of a negative material according to claim 1, characterized in that, The liquid composite additive comprises at least two of resin glue, inorganic acid, inorganic salt solution and solvent, the resin glue comprises at least one of urea-formaldehyde resin glue, epoxy resin glue, phenolic resin glue, liquid pitch glue and latex, the inorganic acid comprises at least one of nitric acid, phosphoric acid, sulfuric acid and hydrochloric acid, the inorganic salt solution comprises at least one of water glass, calcium chloride solution, ferric chloride solution and ferrous chloride solution, and the solvent comprises at least one of water, ethanol, methanol, acetone, xylene, dipropylene glycol dimethyl ether, ethylene glycol monomethyl ether and propylene glycol methyl ether.

8. The process for the continuous graphitization production of a negative material according to claim 1, characterized by the fact that, The carbon ball is subjected to gradient drying at 30 to 105 DEG C first, and then is subjected to gradient baking at 105 to 300 DEG C until the water content is less than or equal to 0.01wt.% before the carbonization and graphitization.

9. The process for the continuous graphitization production of an anode material according to claim 8, characterized in that, The baking and the graphitization further comprise a pre-carbonization treatment, and the baking, the pre-carbonization and the graphitization are integrated. At least one of the following features (a) to (d) is included: (a) the pre-carbonization treatment is performed at a temperature of 500 to 2200 DEG C; (b) the pre-carbonization treatment is performed for 2 to 20 hours; (c) the pre-carbonization treatment is performed under the condition that the differential pressure of the overflow gas is controlled to be 0Pa to +25Pa; 10. The process for the continuous graphitization production of a negative material according to claim 1, characterized by the fact that, (d) the vertical continuous graphitization is performed under the condition that the differential pressure of the overflow gas is controlled to be 0Pa to +25Pa, and the graphitization discharge area is discharged under the condition that the mechanical closed gas is separated from oxygen. At least one of the following features (1) to (6) is included: (1) the pre-treatment comprises crushing the carbon source to a particle size of 0.01mm to 5.00mm and then grinding to obtain the carbon micro-powder with a particle size of 5μm to 25μm; (2) the pressing comprises first buffering the mixed material and then pressing the ball in the ball press to obtain the carbon ball with a particle size of 5mm to 35mm; (3) the temperature of the vertical continuous graphitization is 2200℃ to 3300℃; (4) the time of the vertical continuous graphitization is 6h to 36h; (5) the power of the vertical continuous graphitization is 400KW to 2700KW; (6) the post-treatment comprises scattering and grading to obtain the granule with a particle size of 5μm to 30μm.

Images