Method for preparing carburant by using waste battery black powder acid leaching graphite residue

Abstract

The present application relates to a kind of methods for preparing carbon additive by waste battery black powder acid leaching graphite residue, belong to the technical field of resource utilization of waste lithium battery, comprising the following steps: S1, pretreatment: after the graphite residue of waste battery black powder leaching is washed and purified, to remove residual acid and soluble impurities;S2, batching mixing: the graphite residue after purification is mixed with binder, auxiliary carbon source according to specific proportion uniformly;S3, granulation forming: the mixture is formed into predetermined size of green granules by granulating equipment;S4, high temperature treatment: green granules are subjected to high temperature graphitization treatment;S5, post-processing: the material after graphitization treatment is screened, and carbon additive product is obtained.The method for preparing carbon additive by waste battery black powder acid leaching graphite residue, by the hazardous solid waste-acid leaching graphite residue produced in lithium battery recycling industry, through systematic purification, compatibility and high temperature treatment, successfully converted into high-performance carbon additive product, realized "turning waste into treasure".

Description

Technical Field

[0001] This invention relates to the field of waste lithium battery resource utilization technology, specifically a method for preparing a carbon raiser using graphite residue from acid leaching of waste battery black powder. Background Technology

[0002] With the rapid development of the new energy vehicle and consumer electronics industries, a large number of lithium-ion batteries (including ternary, lithium iron phosphate, and other systems) are reaching their end-of-life. In the process of hydrometallurgically recycling valuable metals (such as nickel, cobalt, manganese, and lithium) from the cathode materials of spent batteries, the black powder obtained after battery crushing and sorting (mainly containing cathode active materials and graphite) is typically acid-leached to dissolve the metals. This process generates a large amount of solid residue, the main component of which is artificial graphite, i.e., "acid-leached graphite slag." This type of graphite slag is usually considered industrial waste or hazardous waste, and its disposal not only increases enterprise costs but also faces severe environmental pressure. On the one hand, graphite slag contains residual heavy metal impurities such as nickel and cobalt; if indiscriminately piled up or landfilled, it will cause soil and water pollution. On the other hand, graphite slag itself has a high fixed carbon content, possessing potential resource utilization value.

[0003] Carbon raisers are key raw materials used in steel smelting and casting to precisely control the carbon content of molten steel or iron. Traditional carbon raisers are mainly prepared using high-purity carbonaceous raw materials such as natural graphite, petroleum coke, and calcined coke, resulting in high production costs. To reduce costs and achieve resource recycling, research has explored the use of various carbonaceous wastes to prepare carbon raisers. For example, Chinese patent CN108059156A discloses a method for preparing high-particle-size carbon raisers using byproducts from graphitization furnaces; CN101775462A discloses a technology for preparing micronized graphite-based carbon raisers using graphite tailings generated during the processing of lithium-ion battery anode materials.

[0004] However, due to the unique characteristics of graphite slag obtained after acid leaching of waste battery black powder—complex composition, high content of metallic impurities, damaged structure, and low purity—there is currently no efficient and high-value resource utilization technology specifically designed for its characteristics. Directly using this type of graphite slag to prepare carbon raisers often faces technical challenges such as low fixed carbon content, high content of harmful impurities such as sulfur and nitrogen, and poor carbon absorption rate, making it difficult to meet the stringent quality requirements of high-end steel smelting for carbon raisers.

[0005] Therefore, developing a proprietary method that can effectively purify the graphite residue from the acid leaching of waste battery black powder and convert it into a high-performance carbon raiser is of great practical significance and application value for realizing the resource utilization of hazardous waste, reducing the production cost of carbon raisers, and promoting the development of a circular economy. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for preparing a carbon raiser using acid-leached graphite residue from waste battery black powder. This method offers advantages such as resource utilization of hazardous waste, excellent product performance, low production cost, and strong process adaptability. It solves the problems of difficult disposal of acid-leached graphite residue from waste battery black powder, high raw material costs of traditional carbon raisers, and the difficulty of efficiently converting such complex waste residue into high-performance products using existing technologies.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for preparing a carbon raiser using graphite residue from acid leaching of waste battery black powder includes the following steps:

[0009] S1. Pretreatment: The graphite residue after leaching waste battery black powder is washed and purified to remove residual acid and soluble impurities.

[0010] S2. Ingredient mixing: The purified graphite slag is mixed evenly with the binder and auxiliary carbon source in a specific ratio;

[0011] S3. Granulation and molding: The mixture is granulated into raw material pellets of a predetermined size using granulation equipment;

[0012] S4. High-temperature treatment: The raw material particles are subjected to high-temperature graphitization treatment.

[0013] S5. Post-processing: The graphitized material is screened to obtain the carbon raiser product.

[0014] Furthermore, the washing and purification treatment described in S1 includes: first washing the acid-leached graphite slag multiple times with water or dilute alkaline solution until neutral, and then drying it; further, it includes performing a secondary acid washing treatment on the washed graphite slag, using hydrochloric acid or sulfuric acid with a concentration of 1-5 mol / L.

[0015] Furthermore, in S2, by weight, the mixture comprises: 70-90 parts of purified graphite slag, 5-15 parts of binder, and 5-15 parts of auxiliary carbon source; the binder is selected from coal tar pitch, petroleum tar pitch, starch, carboxymethyl cellulose, or combinations thereof; the auxiliary carbon source is selected from one or more of carbon black, microcrystalline graphite, anthracite, or calcined coke.

[0016] Furthermore, in S2, purified graphite powder and SiC powder are added to the mixture, wherein the amount of purified graphite powder added is 1-5% of the weight of graphite slag, and the amount of SiC powder added is 0.5-2% of the weight of graphite slag.

[0017] Furthermore, in S3, the granulation process employs extrusion granulation, roller granulation, or stirring granulation, resulting in raw material granules with a particle size of 0.5-5 mm.

[0018] Furthermore, in S4, the high-temperature graphitization treatment is carried out in a graphitization furnace at a temperature of 1800-2800℃ for 1-4 hours, under a protective atmosphere of argon or nitrogen.

[0019] Furthermore, before the high-temperature graphitization process in S4, a carbonization pretreatment step is included, wherein the carbonization pretreatment conditions are: carbonization at 800-1000℃ for 1-2 hours under a protective atmosphere.

[0020] Another technical problem to be solved by the present invention is to provide a carbon raiser with a fixed carbon content ≥95%, a sulfur content ≤0.05%, and a nitrogen content ≤0.03%.

[0021] Furthermore, its fixed carbon content is 96-97.5%, sulfur content is 0.02-0.04%, and nitrogen content is 0.01-0.03%.

[0022] Furthermore, the carbon raiser is used in the steel smelting or casting process to increase the carbon content of molten steel or iron.

[0023] Compared with the prior art, the present invention provides a method for preparing a carbon raiser using graphite residue from acid leaching of waste battery black powder, which has the following beneficial effects:

[0024] 1. This method for preparing carbon raisers using acid-leached graphite residue from waste battery black powder successfully transforms acid-leached graphite residue, a hazardous solid waste generated in the lithium battery recycling industry, into a high-performance carbon raiser product through systematic purification, formulation, and high-temperature treatment. This truly achieves "turning waste into treasure," solves the environmental disposal problem of this hazardous waste, and aligns with the national green circular economy development strategy.

[0025] 2. This method for preparing a carbon raiser using acid-leached graphite residue from waste battery black powder effectively removes metallic impurities through optimized raw material pretreatment (washing and acid leaching); improves material properties through scientific formulation design (addition of binders, auxiliary carbon sources, and modifiers); and significantly enhances the crystallinity and purity of the carbon material through high-temperature graphitization treatment. The resulting carbon raiser has a fixed carbon content of over 95% (preferably 96-97.5%), extremely low levels of harmful impurities such as sulfur and nitrogen (S≤0.05%, N≤0.03%), and a high carbon absorption rate (≥94%). Its comprehensive performance is comparable to that of commercially available high-quality carbon raisers, fully meeting the process requirements of high-end steel smelting and precision casting.

[0026] 3. This method for preparing carbon raisers using acid-leached graphite residue from waste battery black powder uses inexpensive industrial waste residue as the main raw material, replacing expensive natural graphite or calcined coke. This significantly reduces the production cost of the carbon raiser (according to the example, the cost is only about 50-60% of that of commercially available high-quality products), bringing significant economic benefits to enterprises and enhancing the market competitiveness of their products.

[0027] 4. The method for preparing carbon raisers using acid leaching graphite residue from waste battery black powder can be flexibly adjusted and optimized according to the characteristics of specific raw materials and the quality requirements of the final product by means of purification conditions, raw material ratio, granulation method, carbonization and graphitization temperature and time. The process is highly adaptable and easy to implement and promote under different production conditions.

[0028] 5. The method of preparing carbon raisers by acid leaching graphite residue from waste battery black powder adds a high-value-added product output end to the wet recycling process of waste lithium batteries, transforming the original environmental burden into a new profit growth point, improving and extending the industrial chain of lithium battery resource recycling, and enhancing the economy and sustainability of the entire recycling process. Attached Figure Description

[0029] Figure 1 This is a process flow diagram of a method for preparing a carbon raiser using graphite residue from acid leaching of waste battery black powder according to the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1:

[0032] Please see Figure 1 The specific steps of the method for preparing a carbon raiser using graphite residue from acid leaching of waste battery black powder in this embodiment are as follows:

[0033] S1. Pretreatment of graphite slag: Take 1 kg of graphite slag after soaking waste battery black powder, wash it repeatedly with deionized water until neutral, and then treat it with 1 mol / L dilute hydrochloric acid at 60℃ for 2 hours to further remove metal impurities. Rinse the treated graphite slag with water until neutral, and dry it at 105℃ until the moisture content is <1%.

[0034] S2. Ingredient Mixing: Weigh out the following by weight: 80 parts pretreated graphite slag, 10 parts coal tar pitch, 5 parts carbon black, and 1 part SiC powder (based on the weight of graphite slag). Add the above materials to a mixer and mix thoroughly.

[0035] S3. Granulation: The mixture is fed into a double roller briquetting machine and pressed into raw material granules with a particle size of 3-5mm.

[0036] S4. Carbonization treatment: Place the raw material pellets in a carbonization furnace and carbonize at 800°C for 1 hour under nitrogen protection.

[0037] S5. Graphitization treatment: The carbonized particles are placed in a graphitization furnace and treated at 2200℃ for 2 hours under argon protection.

[0038] S6. Screening: The graphitized material is screened through a vibrating screen, and particles of 1-5mm are taken as carbon raiser products.

[0039] The performance of the carbon raiser prepared in this embodiment was tested, and the results are shown in Table 1.

[0040] Table 1: Main performance indicators of the carbon raiser in Example 1

[0041] Testing items unit Test results Detection methods Fixed carbon content % 96.5 GB / T 3521-2008 Sulfur content % 0.03 GB / T 2286-2008 Nitrogen content % 0.02 GB / T 24583-2009 Volatile matter % 0.8 GB / T 3521-2008 Moisture % 0.2 GB / T 3521-2008 Absorption rate % 95.2 -

[0042] Example 2:

[0043] The method for preparing a carbon raiser using graphite residue from acid leaching of waste battery black powder in this embodiment includes the following specific steps:

[0044] S1. Pretreatment of graphite slag: Take 1 kg of graphite slag after soaking waste battery black powder, wash it with 1% sodium hydroxide solution, then wash it with deionized water until neutral, and dry it at 110℃ until the moisture content is <1%.

[0045] S2. Ingredient Mixing: Weigh out the following by weight: 75 parts pretreated graphite slag, 8 parts petroleum asphalt, 7 parts starch-based binder, and 10 parts microcrystalline graphite. Add the above materials to a mixer and mix thoroughly.

[0046] S3. Granulation: The mixture is fed into an extrusion granulator to prepare cylindrical raw material granules with a diameter of 2 mm.

[0047] S4. Graphitization treatment: Place the raw material granules directly into a graphitization furnace and treat at 2500℃ for 1.5 hours under nitrogen protection.

[0048] S5. Screening: The graphitized material is screened through a vibrating screen, and particles of 1-3mm are taken as carbon raiser products.

[0049] The carbon raiser prepared in this embodiment has a fixed carbon content of 97.2%, a sulfur content of 0.025%, a nitrogen content of 0.015%, and an absorption rate of 96.1%.

[0050] Example 3:

[0051] The method for preparing a carbon raiser using graphite residue from acid leaching of waste battery black powder in this embodiment includes the following specific steps:

[0052] S1. Pretreatment of graphite slag: Same as in Example 1.

[0053] S2. Ingredient Mixing: Weigh out the following by weight: 85 parts pretreated graphite slag, 12 parts coal tar pitch, 8 parts anthracite, and 3 parts purified graphite powder (based on the weight of graphite slag). Add the above materials to a mixer and mix thoroughly.

[0054] S3. Granulation: The mixed materials are fed into a mixing granulator, and raw material granules of 0.5-2mm are prepared by controlling the granulation time and speed.

[0055] S4. Carbonization treatment: Place the raw material pellets in a carbonization furnace and carbonize at 900°C for 1.5 hours under nitrogen protection.

[0056] S5. Graphitization treatment: The carbonized particles are placed in a graphitization furnace and treated at 2800℃ for 1 hour under argon protection.

[0057] S6. Screening: The graphitized material is screened through a vibrating screen, and particles of 0.5-2mm are taken as carbon raiser products.

[0058] The carbon raiser prepared in this embodiment has a fixed carbon content of 97.2%, a sulfur content of 0.025%, a nitrogen content of 0.015%, and an absorption rate of 96.1%.

[0059] Comparative Example 1:

[0060] The method disclosed in CN101775462A is adopted, using waste battery black powder acid leaching graphite residue as raw material, mixing, granulating and drying in a ratio of 80% micro-powder graphite and 20% starch-based binder, but without high-temperature graphitization treatment.

[0061] The product obtained has a fixed carbon content of 88.5%, a sulfur content of 0.12%, a nitrogen content of 0.08%, and an absorption rate of 82.3%.

[0062] Performance comparison:

[0063] The performance of Examples 1-3 of the present invention was compared with that of Comparative Example 1 and a commercially available high-quality carbon raiser. The results are shown in Table 2.

[0064] Table 2

[0065] sample Fixed carbon (%) Sulfur content (%) Nitrogen content (%) Absorption rate (%) Production cost (RMB / ton) Example 1 96.5 0.03 0.02 95.2 5800 Example 2 95.8 0.04 0.025 94.5 6200 Example 3 97.2 0.025 0.015 96.1 7500 Comparative Example 1 88.5 0.12 0.08 82.3 4500 Commercial high-quality carbon raisers 98.5 0.02 0.01 96.5 12000

[0066] As shown in Table 2, the carbon raisers prepared in Examples 1-3 of the present invention are significantly better than Comparative Example 1 in terms of fixed carbon content, sulfur and nitrogen impurity content and absorption rate. They are close to the performance of commercial high-quality carbon raisers, but the production cost is significantly reduced.

[0067] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a carbon raiser using graphite residue from acid leaching of waste battery black powder, characterized in that, Includes the following steps: S1. Pretreatment: The graphite residue after leaching waste battery black powder is washed and purified to remove residual acid and soluble impurities. S2. Ingredient mixing: The purified graphite slag is mixed evenly with the binder and auxiliary carbon source in a specific ratio; S3. Granulation and molding: The mixture is granulated into raw material pellets of a predetermined size using granulation equipment; S4. High-temperature treatment: The raw material particles are subjected to high-temperature graphitization treatment. S5. Post-processing: The graphitized material is screened to obtain the carbon raiser product.

2. The method for preparing a carbon raiser using acid-leached graphite residue from waste battery black powder according to claim 1, characterized in that, The washing and purification process described in S1 includes: first, washing the acid-leached graphite slag multiple times with water or dilute alkaline solution until neutral, followed by drying; and further includes performing a secondary acid washing treatment on the washed graphite slag, using hydrochloric acid or sulfuric acid with a concentration of 1-5 mol / L.

3. The method for preparing a carbon raiser using acid-leached graphite residue from waste battery black powder according to claim 1, characterized in that, In S2, by weight, the mixture comprises: 70-90 parts of purified graphite slag, 5-15 parts of binder, and 5-15 parts of auxiliary carbon source; the binder is selected from coal tar pitch, petroleum tar pitch, starch, carboxymethyl cellulose or a combination thereof; the auxiliary carbon source is selected from one or more of carbon black, microcrystalline graphite, anthracite or calcined coke.

4. The method for preparing a carbon raiser using acid-leached graphite residue from waste battery black powder according to claim 1, characterized in that, In S2, purified graphite powder and SiC powder are also added to the mixture, wherein the amount of purified graphite powder added is 1-5% of the weight of graphite slag, and the amount of SiC powder added is 0.5-2% of the weight of graphite slag.

5. The method for preparing a carbon raiser using acid-leached graphite residue from waste battery black powder according to claim 1, characterized in that, In S3, the granulation process is carried out by extrusion granulation, roller granulation or stirring granulation, and the resulting raw material particles have a particle size of 0.5-5 mm.

6. The method for preparing a carbon raiser using acid-leached graphite residue from waste battery black powder according to claim 1, characterized in that, In S4, the high-temperature graphitization process is carried out in a graphitization furnace at a temperature of 1800-2800℃ for 1-4 hours, under a protective atmosphere of argon or nitrogen.

7. The method for preparing a carbon raiser using acid-leached graphite residue from waste battery black powder according to claim 1, characterized in that, Before S4 undergoes high-temperature graphitization, it also includes a carbonization pretreatment step for the raw material particles. The carbonization pretreatment conditions are: carbonization at 800-1000℃ for 1-2 hours under a protective atmosphere.

8. A carbon raiser, prepared by the method described in any one of claims 1-7, using waste battery black powder acid leaching graphite residue to prepare the carbon raiser, characterized in that, Its fixed carbon content is ≥95%, sulfur content is ≤0.05%, and nitrogen content is ≤0.03%.

9. A carbon raiser according to claim 8, characterized in that, Its fixed carbon content is 96-97.5%, sulfur content is 0.02-0.04%, and nitrogen content is 0.01-0.03%.

10. A carbon raiser according to claim 8, characterized in that, The carbon-enhancing agent is used in the steel smelting or casting process to increase the carbon content of molten steel or iron.

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