Coke raw material applicability evaluation method based on high-temperature treatment

Abstract

The invention discloses a coke raw material applicability evaluation method based on high-temperature treatment, and belongs to the field of graphite. The invention mainly aims to overcome the defects that the existing calcined coke manufacturing process is complicated, the feeding amount is large, the coke source is difficult to screen and the like. The method comprises the following steps: step 1, dividing blocky coke crushed particles into two parts, step 2, putting one part of coke particles into heating and stirring equipment, carrying out heat treatment, crushing, spheroidizing and graphitizing processing under the protection of nitrogen, and testing the capacity and the powder compaction density; 3, under the same condition in the step 2, the other part of coke particles are sequentially subjected to smashing, spheroidizing and graphitizing processing, and the capacity and the powder compaction density are tested; 4, the capacity is increased by 3-5 mAh / g, the powder compaction is increased by 0.02-0.05 g / cm < 3 >, and it is proved that the coke raw material is applicable. By adopting the process disclosed by the invention, whether the energy density of the coke source can be obviously improved through high-temperature treatment or not can be more quickly evaluated by utilizing the existing conditions, the process has guiding significance on selection of coke raw materials of a project, and the preparation process is simple.

Description

Technical Field

[0001] This invention belongs to the field of graphite, and more specifically, relates to a method for evaluating the suitability of coke raw materials based on high-temperature treatment. Background Technology

[0002] Lithium-ion batteries are widely used in power, energy storage, and consumer electronics. Currently, their anode materials are mainly divided into two categories: carbon materials and non-carbon materials, with graphite-based carbon materials dominating due to their mature technology and market acceptance. However, with the continuous iteration of technology and market demands, the performance requirements for graphite anode materials are increasingly stringent.

[0003] Improving the energy density of graphite anodes mainly relies on two approaches: selecting high-energy-density coke feedstock and optimizing aggregate particle size. Among these, the selection of coke feedstock is crucial to the final energy density. Typically, obtaining high-energy-density coke requires high-temperature treatment during coke production. However, traditional evaluation methods require the input of hundreds of tons of feedstock for calcination furnace production trials to determine whether the coke source is suitable for producing high-energy-density coke. This method not only consumes a huge amount of raw materials but is also extremely inefficient.

[0004] On the other hand, while existing raw materials such as calcined needle coke can be used to produce graphite anodes with relatively high energy density, their procurement costs are also significantly increased. Furthermore, the energy density of graphite anodes made from commercially available coke sources may be excessive or insufficient for specific battery applications.

[0005] Therefore, developing a simple and efficient method for evaluating the high-temperature treatment of coke raw materials is particularly urgent for quickly screening suitable raw materials and meeting differentiated needs. Summary of the Invention

[0006] To address the differentiated demands of the lithium-ion battery graphite anode market, this study analyzed whether different types of coke exhibit significant capacity enhancement potential after high-temperature treatment. It also compared key indicators such as capacity and compaction density of the anode materials obtained after graphitization of various coke raw materials. The research indicates that if companies possess their own calcination equipment and processes, and implement customized calcination treatments, they can produce graphite anode materials that better meet specific needs. Therefore, rapid raw material screening and guidance for project development are crucial.

[0007] This invention aims to overcome the shortcomings of existing calcined coke preparation processes, such as complexity, high raw material consumption, and difficulty in coke source selection. It provides a method for evaluating high-temperature coke treatment to assess whether coke raw materials are suitable for preparing high-energy-density graphite anodes. Using the process described in this invention, the potential for significantly improving the energy density of coke sources through high-temperature treatment can be evaluated more quickly under existing conditions, providing clear guidance for the selection of coke raw materials for projects. Furthermore, the preparation process itself is simple.

[0008] To address the aforementioned technical problems, the present invention adopts the following technical solution: The purpose of this invention is to provide a method for evaluating the suitability of coke feedstock based on high-temperature treatment, comprising the following steps: Step 1: Divide the lumpy coke into 2 parts; Step 2: One portion of coke particles is put into a heating and stirring device, heat-treated under nitrogen protection, crushed, spheroidized, and graphitized, and its capacity and powder compaction density are tested. Step 3: Under the same conditions as in Step 2, another batch of coke particles is sequentially crushed, spheroidized, and graphitized, and the volume and powder compaction density are tested. Step 4: For graphite made from heat-treated coke, compare the capacity and powder compaction density from steps 3 and 2. The capacity shows an increase of 3 mAh / g-5 mAh / g, and the powder compaction density increases by 0.02-0.05 g / cm³. 3 This proves that the coke raw material is suitable for using this method to increase energy density.

[0009] Further specifying, the equipment used for heat treatment is a vertical autoclave, a horizontal autoclave, or a rotary furnace, such as a vertical autoclave.

[0010] Further specifying, the crushing equipment used is a toothed crusher, and the crushing is to produce particles of 1cm-5cm.

[0011] Further specifying, the heat treatment temperature of the crushed coke particles is between 400℃ and 800℃, for example, 600℃.

[0012] Further, the heat treatment time for crushed coke particles is specified as 5h-25h, 8h.

[0013] Further, the volatile matter content of the coke raw material should be <15%, preferably between 3% and 15%.

[0014] Further, the volatile matter content of the coke after heat treatment is less than 5%.

[0015] Further specifying, the true density of the heat-treated coke is >1.45 g / cm³. 3 .

[0016] Further specifying, the equipment used for pulverization is a mechanical mill, roller mill, or air jet mill.

[0017] Further specified, after pulverization, D50 = 5.0-25.0 μm, for example 10.0 μm.

[0018] To further specify, the equipment used for spheroidization is a conventional shaping machine.

[0019] Further specifying, the D50 after spheroidization treatment is 6.0-26.0 μm, for example, 11.0 μm.

[0020] Further specifying, the graphitization temperature is between 2300℃ and 3100℃, for example, 2600℃.

[0021] Furthermore, the graphitization time is specified to be 24h-96h, for example, 35h.

[0022] Further specified, the heating rate during graphitization is between 1℃ / min and 5℃ / min, for example, 2℃ / min.

[0023] Compared with the prior art, the present invention has the following beneficial effects: This invention requires a smaller amount of material, saving energy, raw materials, and manpower.

[0024] This invention utilizes existing equipment for operation, maximizing resource utilization.

[0025] This invention does not rely on the conditions of a coking plant and can be customized to develop a suitable shallow calcination process for coking raw materials. Detailed Implementation

[0026] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, while not limiting the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0027] Example 1: The method for assessing the suitability of coke raw materials based on high-temperature treatment in this example is implemented through the following steps: Step 1: Crush the 10% volatile coke (petroleum coke A) into 1cm-3cm particles using mechanical crushing equipment, and divide it into two portions. Step 2: One portion of coke particles is put into a heating and stirring device (vertical reactor) for heat treatment. Under nitrogen protection, the heat treatment of coke particles is divided into two stages: Stage 1: stirring speed is 10 r / min, heating temperature is 450℃, and heating time is 5 h; Stage 2: stirring speed is 10 r / min, heating temperature is 650℃, and heating time is 4 h. The heat-treated coke particles had a volatile matter content of 4% and a true density of 1.46 g / cm³. 3 ; The heat-treated coke particles were pulverized by a mechanical mill, and the median particle size D50 after pulverization was controlled at 10.0 μm. The pulverized coke powder is then spheroidized using a shaping machine, and the median particle size D50 after spheroidization is controlled at 10.5μm. The spheroidized coke powder was then subjected to high-temperature graphitization treatment. The graphitization treatment was carried out at 3000℃ with a heating rate of 2-3℃ / min for 35 hours. The cooled graphite powder was then subjected to 325-mesh sieve treatment to obtain graphite material sample 1. The particle size, tapping, specific surface area, volume, and powder compaction index of sample 1 were tested. Step 3: Crush, spheroidize, and graphitize another batch of untreated coke particles. The specific operation method and parameters are the same as those in Step 2, to obtain graphite material sample 2. The particle size, tapping, specific surface area, volume, and powder compaction index of sample 2 were tested.

[0028] Example 2 evaluates whether the energy density of the coke source can be significantly improved through high-temperature treatment. The steps are as follows: Step 1: Crush the lumpy coke (asphalt coke B) with 6% volatile matter into 1-3cm particles using mechanical crushing equipment, and divide it into two portions. Step 2: One portion of coke particles is put into a heating and stirring device (vertical reactor) for heat treatment. Under nitrogen protection, the heat treatment of coke particles is divided into two stages: Stage 1: stirring speed is 10 r / min, heating temperature is 450℃, and heating time is 5 h; Stage 2: stirring speed is 10 r / min, heating temperature is 650℃, and heating time is 4 h. The heat-treated coke particles had a volatile matter content of 3% and a true density of 1.44 g / cm³. 3 ; The heat-treated coke particles were pulverized by a mechanical mill, and the median particle size D50 after pulverization was controlled at 10.0 μm. The pulverized coke powder is then spheroidized using a shaping machine, and the median particle size D50 after spheroidization is controlled at 10.5μm. The spheroidized coke powder was then subjected to high-temperature graphitization treatment. The graphitization treatment was carried out at 3000℃ with a heating rate of 2-3℃ / min for 35 hours. The cooled graphite powder was then subjected to 325-mesh sieve treatment to obtain graphite material sample 3. The particle size, tapping, specific surface area, volume, and powder compaction index of sample 3 were tested. Step 3: Crush, spheroidize, and graphitize another batch of untreated coke particles. The specific operation method and parameters are the same as those in Step 2, to obtain graphite material sample 4. The particle size, compaction, specific surface area, volume, and powder compaction index of sample 4 were tested.

[0029] Example 3 evaluates whether the energy density of the coke source can be significantly improved through high-temperature treatment. The steps are as follows: Step 1: Crush the 15% volatile coke (petroleum coke C) into 1-3cm particles using mechanical crushing equipment, and divide it into two portions. Step 2: One portion of coke particles is put into a heating and stirring device (vertical reactor) for heat treatment. Under nitrogen protection, the heat treatment of coke particles is divided into two stages: Stage 1: stirring speed is 10 r / min, heating temperature is 450℃, and heating time is 6h; Stage 2: stirring speed is 10 r / min, heating temperature is 650℃, and heating time is 5h. The heat-treated coke particles had a volatile matter content of 4% and a true density of 1.47 g / cm³. 3 ; The heat-treated coke particles were pulverized by a mechanical mill, and the median particle size D50 after pulverization was controlled at 10.0 μm. The pulverized coke powder is then spheroidized using a shaping machine, and the median particle size D50 after spheroidization is controlled at 10.5μm. The spheroidized coke powder was then subjected to high-temperature graphitization treatment. The graphitization treatment was carried out at 3000℃ with a heating rate of 2-3℃ / min for 35 hours. The cooled graphite powder was then subjected to 325-mesh sieve treatment to obtain graphite material sample 5. The particle size, tapping, specific surface area, volume, and powder compaction index of sample 5 were tested. Step 3: Crush, spheroidize, and graphitize another batch of untreated coke particles. The specific operation method and parameters are the same as those in Step 2, to obtain graphite material sample 6. The particle size, tapping, specific surface area, volume, and powder compaction index of sample 6 were tested.

[0030] Example 4 evaluates whether the energy density of the coke source can be significantly improved through high-temperature treatment. The steps are as follows: Step 1: Crush the 10% volatile coke (petroleum coke A) into 1-3cm particles using mechanical crushing equipment, and divide it into two portions. Step 2: One portion of coke particles is put into a heating and stirring device (vertical reactor) for heat treatment. Under nitrogen protection, the heat treatment of coke particles is divided into two stages: Stage 1: stirring speed is 10 r / min, heating temperature is 450℃, and heating time is 5 h; Stage 2: stirring speed is 10 r / min, heating temperature is 650℃, and heating time is 4 h. The heat-treated coke particles had a volatile matter content of 4% and a true density of 1.46 g / cm³. 3 ; The heat-treated coke particles were pulverized by a mechanical mill, and the median particle size D50 after pulverization was controlled at 16.0 μm. The pulverized coke powder is then spheroidized using a shaping machine, and the median particle size D50 after spheroidization is controlled at 16.5μm. The spheroidized coke powder was then subjected to high-temperature graphitization treatment. The graphitization treatment was carried out at 3000℃ with a heating rate of 2-3℃ / min for 35 hours. The cooled graphite powder was then subjected to 325-mesh sieve treatment to obtain graphite material sample 7. The particle size, tapping, specific surface area, volume, and powder compaction index of sample 7 were tested. Step 3: Crush, spheroidize, and graphitize another batch of untreated coke particles. The specific operation method and parameters are the same as those in Step 2, to obtain graphite material sample 8. The particle size, compaction, specific surface area, volume, and powder compaction index of sample 8 were tested.

[0031] Example 5 evaluates whether the energy density of the coke source can be significantly improved through high-temperature treatment. The steps are as follows: Step 1: Crush the 10% volatile coke (petroleum coke A) into 1-3cm particles using mechanical crushing equipment, and divide it into two portions. Step 2: One portion of coke particles is put into a heating and stirring device (vertical reactor) for heat treatment. Under nitrogen protection, the heat treatment of coke particles is divided into two stages: Stage 1: stirring speed is 10 r / min, heating temperature is 450℃, and heating time is 5 h; Stage 2: stirring speed is 10 r / min, heating temperature is 650℃, and heating time is 4 h. The heat-treated coke particles had a volatile matter content of 4% and a true density of 1.46 g / cm³. 3 ; The heat-treated coke particles were pulverized by a mechanical mill, and the median particle size D50 after pulverization was controlled at 6.0 μm. The pulverized coke powder is then spheroidized using a shaping machine, and the median particle size D50 after spheroidization is controlled at 6.5μm. The spheroidized coke powder was then subjected to high-temperature graphitization treatment. The graphitization treatment was carried out at 3000℃ with a heating rate of 2-3℃ / min for 35 hours. The cooled graphite powder was then subjected to 325-mesh sieve treatment to obtain graphite material sample 9. The particle size, tapping, specific surface area, volume, and powder compaction index of sample 9 were tested. Step 3: Another batch of untreated coke particles is crushed, spheroidized, and graphitized. The specific operation method and parameters are the same as those in Step 2, to obtain graphite material sample 10. The particle size, compaction, specific surface area, volume, and powder compaction index of sample 10 were tested.

[0032] Table 1

[0033] Test results: Based on the experimental data obtained from samples 1-6 in Table 1, the graphite produced from coke A and C after heat treatment showed significantly improved volume and powder compaction compared to the graphite produced from coke A and C without heat treatment. The graphite produced from coke B after heat treatment showed almost the same volume and powder compaction compared to the graphite produced from coke B without heat treatment. This indicates that coke A and C are more suitable for improving energy density using this heat treatment method.

[0034] Based on the experimental data obtained from samples 1-2 and 7-10 in Table 1, under the same raw materials and preparation process, smaller particle sizes are not suitable for using this heat treatment method to improve energy density.

[0035] The specific embodiments of the present invention have been described above. It should be noted that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for assessing the suitability of coke feedstock based on high-temperature treatment, characterized in that, Includes the following steps: Step 1: Divide the lumpy coke into two portions. Step 2: One portion of coke particles is put into a heating and stirring device, heat-treated under nitrogen protection, crushed, spheroidized, and graphitized, and its capacity and powder compaction density are tested. Step 3: Under the same conditions as in Step 2, another batch of coke particles is sequentially crushed, spheroidized, and graphitized, and the volume and powder compaction density are tested. Step 4: Graphite made from heat-treated coke exhibits a capacity increase of 3-5 mAh / g, and a powder compaction increase of 0.02 g / cm³. 3 -0.05g / cm 3 This proves that the coke raw material is suitable for using this method to increase energy density.

2. The method according to claim 1, characterized in that, The crushing equipment used is a toothed crusher, which crushes particles into 1cm-5cm particles.

3. The method according to claim 1, characterized in that, The crushed coke particles are heat-treated at 400℃-800℃ for 5h-25h.

4. The method according to claim 1, characterized in that, The volatile matter content of the coke feedstock is less than 15%.

5. The method according to claim 1, characterized in that, The equipment used for heat treatment is a vertical autoclave, a horizontal autoclave, or a rotary drum furnace.

6. The method according to claim 1, characterized in that, The volatile matter content of the heat-treated coke is <5%; the true density is >1.45 g / cm³. 3 .

7. The method according to claim 1, characterized in that, The equipment used for pulverization includes mechanical mills, roller mills, or air jet mills.

8. The method according to claim 1, characterized in that, After pulverization, D50 = 5.0-25.0 μm.

9. The method according to claim 1, characterized in that, The equipment used for spheroidization was a conventional shaping machine; after spheroidization, D50 = 6.0-26.0 μm.

10. The method according to claim 1, characterized in that, The graphitization temperature is between 2400℃ and 3100℃; the graphitization time is between 24h and 96h; and the heating rate during the graphitization process is between 1℃ / min and 5℃ / min.

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