Method for obtaining graphite raw material based on industrial waste

Abstract

The invention relates to a method for obtaining a graphite raw material based on industrial waste, which comprises the following steps: S1, carrying out crushing treatment on recycled waste graphite electrodes to obtain graphite slag; s2, performing acid treatment on the graphite slag, and soaking for a first preset time; s3, washing the soaked graphite slag mixed solution with water until the graphite slag mixed solution is neutral; s4, drying to obtain acid-treated graphite slag; s5, weighing acid-treated graphite slag, adding a 2M HCl solution, and stirring under an ice bath condition until the graphite slag does not float on the surface any more; s6, adding a first coating agent, continuously stirring until the temperature of the system is lower than 10 DEG C, then adding a second coating agent, and waiting for reaction for a second preset time; s7, after the reaction is completed, filtering, washing and drying are conducted, and coated graphite is obtained; and S8, graphitizing the coated graphite to obtain regenerated graphite.

Description

Technical Field

[0001] The present application relates to the field of material manufacturing, and in particular to a method for obtaining graphite raw materials based on industrial waste. Background Art

[0002] Graphite electrode is an important conductive material in modern industry and is widely used in electric furnace steelmaking, electrolysis, electroplating and other fields.

[0003] With the acceleration of the global industrialization process, the demand for high-performance materials in various industries continues to increase, especially in high-tech industries such as electronics, automobiles, energy, and aviation. The special properties of graphite make it have important application potential in these fields. Graphite materials can be used to manufacture efficient heat exchangers, heat dissipation systems for electronic components, electrode materials for batteries, thermal conductive sheets, anti-corrosion components, etc. In the fields of new energy vehicles, battery technology, etc., the high conductivity, high stability and high temperature resistance of special graphite make it an important material choice.

[0004] However, as a carbon material, graphite has limited resource reserves, and the mining of natural graphite has a certain destructive effect on the ecological environment. With the intensification of global resource shortage problems, the recycling and reuse of discarded graphite electrodes has a significant resource-saving effect. In addition, discarded graphite electrodes contain a large amount of harmful substances, and direct disposal will cause pollution to water sources, soil and air. Therefore, the recycling of graphite electrodes is not only a need for resource conservation, but also an important measure for environmental protection. In addition, graphite electrodes will produce waste due to oxidation, burning and other reasons during use. Especially in the process of electric furnace steelmaking, due to the high temperature, the consumption of graphite electrodes is large, and the volume and weight of discarded electrodes are also considerable. If these discarded graphite electrodes are not properly disposed of, they will not only take up a lot of space, but also may pollute the environment. At the same time, the price of graphite electrodes is high, the energy consumption in its manufacturing process is huge, and the requirements for raw materials are relatively harsh. At the same time, with the popularization of electric furnace steelmaking technology, the demand for graphite electrodes has shown a rapid growth trend, the demand for raw materials has also increased, and the mining of raw materials will also cause a burden on the environment. Summary of the invention

[0005] The present application provides a method for obtaining graphite raw materials based on industrial waste to solve the problem of recycling and reuse of waste graphite products.

[0006] In a first aspect, the present application provides a method for obtaining graphite raw materials based on industrial waste, comprising the steps of: S1, crushing the recycled waste graphite electrodes to obtain graphite slag; S2, treating the graphite slag with acid and soaking it for a first preset time; S3, washing the immersed graphite slag mixed solution with water until it becomes neutral; S4, drying to obtain acid-treated graphite slag; S5, weighing the acid-treated graphite slag, adding 2M HCl solution, and stirring in an ice bath until the graphite slag no longer floats on the surface; S6, adding the first coating agent, continuing stirring until the system temperature is lower than 10°C, then adding the second coating agent, and waiting for the reaction for a second preset time; S7, after the reaction is completed, filtering, washing and drying are performed to obtain coated graphite; S8, graphitizing the coated graphite to obtain regenerated graphite.

[0007] Preferably, in step S2, the acid treatment is performed by mixing and stirring the graphite slag with a 2M H2SO4 acid solution in a ratio of 1:1-10.

[0008] Preferably, in step S2, the first preset time is 17-24 hours.

[0009] Preferably, in step S5, 5-7 ml of 2M HCl solution is added to every 5 g of acid-treated graphite slag.

[0010] Preferably, in step S6, 0.4-0.6 ml of the first coating agent is added to every 5 g of acid-treated graphite slag, and the first coating agent is epoxy resin.

[0011] Preferably, in step S6, 0.5-1.2 ml of a second coating agent is added to every 5 g of acid-treated graphite slag, and the second coating agent is a modified amine curing agent.

[0012] Preferably, in step S6, the second coating agent is added in a continuous dripping manner.

[0013] Preferably, in step S6, the second preset time is 16-20 hours.

[0014] Preferably, in step S7, the filtering method is suction filtration.

[0015] Preferably, in step S8, graphitization of the coated graphite is achieved by heating.

[0016] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art: The method provided in the embodiment of the present application recycles waste graphite electrodes (i.e., industrial waste), processes the waste graphite electrodes to obtain coated graphite, and obtains regenerated graphite after desertification. The metal element content of the regenerated graphite is greatly reduced, and the material properties are improved, which meets the raw material requirements for making graphene, thereby realizing the recycling and reuse of waste electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0019] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0020] Figure 1 A flow chart of a method for obtaining graphite raw materials based on industrial waste provided in an embodiment of the present application; Figure 2A is the Raman spectrum of waste graphite; Figure 2B Raman spectrum of regenerated graphite; Figure 3A is the SEM image of graphite slag; Figure 3B This is the SEM image of recycled graphite. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0022] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0023] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0024] In order to solve the technical problem of recycling waste graphite electrodes in the prior art, the present application provides a method for obtaining graphite raw materials based on industrial waste, which can convert waste graphite electrodes into recycled graphite, which can be used to produce graphene materials.

[0025] Figure 1 A method for obtaining graphite raw materials based on industrial waste provided in an embodiment of the present application comprises the steps of: S1, crushing the recycled waste graphite electrodes to obtain graphite slag; S2, treating the graphite slag with acid and soaking it for a first preset time; S3, washing the immersed graphite slag mixed solution with water until it becomes neutral; S4, drying to obtain acid-treated graphite slag; S5, weighing the acid-treated graphite slag, adding 2M HCl solution, and stirring in an ice bath until the graphite slag no longer floats on the surface; S6, adding the first coating agent, continuing stirring until the system temperature is lower than 10°C, then adding the second coating agent, and waiting for the reaction for a second preset time; S7, after the reaction is completed, filtering, washing and drying are performed to obtain coated graphite; S8, graphitizing the coated graphite to obtain regenerated graphite.

[0026] In step S1 of this embodiment, waste graphite electrodes are an important resource, and recycling can reduce resource waste and environmental pollution. The recycled waste graphite electrodes need to be crushed before preparing regenerated graphite to obtain graphite slag for further processing. After recycling, the waste graphite electrodes can be mechanically crushed into small particles (i.e., graphite slag) by a grinder to facilitate subsequent processing.

[0027] In step S2 of this embodiment, the acid treatment is to mix and stir the graphite slag with 2M H2SO4 acid solution in a ratio of 1:1-10. The acid treatment process is to oxidize the graphite to facilitate the subsequent treatment steps.

[0028] Furthermore, in step S2, the first preset soaking time is 17-24 hours, and the purpose of soaking is to fully oxidize the graphite.

[0029] In step S3 of this embodiment, the immersed graphite slag mixed solution is washed by adding deionized water and a dilute acid solution for alternate washing until the pH value is close to neutral.

[0030] In step S4 of this embodiment, the drying process is performed by drying the mixed solution under high temperature conditions, for example, continuously drying at 50-120° C. for 24-72 hours until the water is evaporated to obtain acid-treated graphite slag.

[0031] In step S5 of the present embodiment, 5-7 ml of 2M HCl solution is added to every 5 g of acid-treated graphite slag, and the mixture is stirred in an ice bath until the graphite no longer floats on the surface, wherein 2M HCl is used as a reducing agent to react with the acid-treated graphite slag, and the temperature is low under the ice bath condition, which can prevent the reduced graphite from being oxidized again.

[0032] In step S6 of this embodiment, 0.4-0.6 ml of the first coating agent is added to every 5 g of acid-treated graphite slag. The first coating agent is epoxy resin. Of course, the first coating agent liquid can be made of other resin materials, such as polyurethane, acrylic acid, two-component silicone rubber and the like.

[0033] In step S6 of this embodiment, 0.5-1.2 ml of a second coating agent is added to every 5 g of acid-treated graphite slag, and the second coating agent is a modified amine curing agent.

[0034] Specifically, the second coating agent is added in a continuous dripping manner so that the second coating agent can be fully mixed with the graphite to coat the graphite.

[0035] In step S6 of this embodiment, the second preset time for reaction after adding the second coating agent is 16-20 hours to allow for sufficient reaction.

[0036] In step S7 of this embodiment, the filtering method is suction filtration, which can improve the filtering efficiency.

[0037] In step S8 of this embodiment, graphitization of the coated graphite is achieved by heating. Of course, graphitization can also be achieved by other methods, such as ball milling, chemical reduction, etc.

[0038] Based on the above treatment method, a large amount of metal elements in graphite slag can be removed, and the metal element content of the obtained recycled graphite is greatly reduced, which can be used as a raw material for the production of graphene and its related products. Specifically, through the analysis of trace metal elements in graphite slag and recycled graphite, the metal element content of the two is shown in the following table: Table 1 Content of trace metal elements in graphite slag and recycled graphite like Figure 2A and Figure 2B The Raman spectra of waste graphite and regenerated graphite are shown in Figure 1. Through Raman spectroscopy analysis, the spectra show two peaks centered at around 1360 and 1580 cm-1, which correspond to the disorder-induced Raman mode (D peak) and the in-plane optical vibration Raman mode (G peak) in the carbon material, respectively. The D peak characterizes the structural defects in the carbon material. The ratio of the D peak intensity to the G peak intensity (ID / IG) is usually used to measure the degree of graphitization. The higher the ID / IG value, the more structural defects there are and the lower the degree of graphitization. As can be seen from the figure, compared with the ID / IG value of 0.21 for waste graphite, the ID / IG value of the regenerated and repaired PCR graphite is 0.14, indicating that the degree of defects in the material is significantly reduced after the waste graphite is regenerated and repaired.

[0039] like Figure 3A and Figure 3B Shown are SEM images (scanning electron microscope) of graphite slag and regenerated graphite. From the image, it can be seen that the particle size of the sample is significantly increased after the graphite slag is repaired and regenerated.

[0040] From the above analysis, it can be seen that the degree of material defects in the recycled graphite has been significantly reduced, and the conditions are now suitable for the preparation of graphene.

[0041] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0042] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0043] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for obtaining graphite raw materials based on industrial waste, characterized in that: Includes steps: S1, crushing the recycled waste graphite electrodes to obtain graphite slag; S2, treating the graphite slag with acid and soaking it for a first preset time; S3, washing the immersed graphite slag mixed solution with water until it becomes neutral; S4, drying to obtain acid-treated graphite slag; S5, weighing the acid-treated graphite slag, adding 2M HCl solution, and stirring in an ice bath until the graphite slag no longer floats on the surface; S6, adding the first coating agent, continuing stirring until the system temperature is lower than 10°C, then adding the second coating agent, and waiting for the reaction for a second preset time; S7, after the reaction is completed, filtering, washing and drying are performed to obtain coated graphite; S8, graphitizing the coated graphite to obtain regenerated graphite.

2. The method according to claim 1, characterized in that In the step S2, the acid treatment is performed by mixing and stirring the graphite slag with a 2M H2SO4 acid solution in a ratio of 1:1-10.

3. The method according to claim 2, characterized in that In step S2, the first preset time is 17-24 hours.

4. The method according to claim 1, characterized in that: In step S5, 5-7 ml of 2M HCl solution is added to every 5 g of acid-treated graphite slag.

5. The method according to claim 4, characterized in that In the step S6, 0.4-0.6 ml of the first coating agent is added to every 5 g of the acid-treated graphite slag, and the first coating agent is an epoxy resin.

6. The method according to claim 4, characterized in that In the step S6, 0.5-1.2 ml of a second coating agent is added to every 5 g of the acid-treated graphite slag, and the second coating agent is a modified amine curing agent.

7. The method according to claim 1, characterized in that In the step S6, the second coating agent is added in a continuous dripping manner.

8. The method according to claim 1, characterized in that In step S6, the second preset time is 16-20 hours.

9. The method according to claim 1, characterized in that: In step S7, the filtering method is suction filtration.

10. The method according to claim 1, characterized in that In the step S8, graphitization of the coated graphite is achieved by heating.

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