A method for producing a porous graphite block from a fractionated natural graphite particle

Abstract

The application provides a method for preparing a porous graphite block from graded natural graphite particles, and the method comprises the following steps: uniformly mixing natural graphite particles with different preset particle sizes in proportion to form a mixture; performing swelling treatment on the mixture by using sulfuric acid and hydrogen peroxide; and washing, filtering and drying the obtained product to obtain a porous graphite block; wherein the natural graphite particles with different preset particle sizes comprise natural graphite particles with a particle size of-45 mu m, natural graphite particles with a particle size of 45 mu m to 75 mu m, natural graphite particles with a particle size of 75 mu m to 270 mu m and natural graphite particles with a particle size of +270 mu m; and the method for preparing a porous graphite block from graded natural graphite particles can realize the preparation of a porous graphite block with certain mechanical strength and uniform pores, so that the adsorption capacity and recycling performance of low-viscosity oil or an organic solvent can be improved.

Description

Technical Field

[0001] This invention relates to the field of porous graphite adsorbent materials and their preparation technology, and in particular to a method for preparing porous graphite blocks from graded natural graphite particles. Background Technology

[0002] During oil development, processing, storage, and transportation, crude oil or refined oil products may leak into the sea for various reasons. Oil spills spread rapidly and form an oil film on the sea surface, blocking oxygen from dissolving in seawater, leading to oxygen depletion, the death of plankton, fish, and shrimp, and causing catastrophic consequences for the marine ecosystem. Furthermore, benzene and its derivatives contained in petroleum are highly volatile; inhalation can cause symptoms such as lethargy, coma, headache, and tearing, posing potential health hazards. Expanded graphite, prepared by intercalating and expanding natural graphite, consists of worm-like particles with a porous structure and excellent oleophilic and hydrophobic properties, making it an ideal material for oil spill disposal. In addition to the adsorption properties of the worm-like particles themselves, the spaces formed by the particles and their entanglement also exhibit high adsorption capacity for high-viscosity oil.

[0003] However, for the adsorption of low-viscosity oils or organic solvents, the large spaces formed between the worm particles are detrimental to improving adsorption performance. Furthermore, the difficulty in recovering and reusing disintegrated expanded graphite particles hinders the application of expanded graphite in oil spill disposal. Therefore, it is necessary to develop a simple and effective method to prepare porous graphite blocks with certain mechanical strength and uniform pore size, in order to improve the adsorption capacity and recycling performance of low-viscosity oils or organic solvents. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, this invention provides a method for preparing porous graphite blocks from graded natural graphite particles, the specific details of which are as follows:

[0005] This invention provides a method for preparing porous graphite blocks from graded natural graphite particles, the method comprising:

[0006] Natural graphite particles with different preset particle sizes are mixed uniformly in proportion to form a mixed material;

[0007] The mixture was expanded using concentrated sulfuric acid and hydrogen peroxide, and the resulting material was washed, filtered, and dried to obtain porous graphite blocks.

[0008] The natural graphite particles with different preset particle sizes include: natural graphite particles with a particle size of -45 μm, natural graphite particles with a particle size of 45 μm to 75 μm, natural graphite particles with a particle size of 75 μm to 270 μm, and natural graphite particles with a particle size of +270 μm.

[0009] Optionally, the mass ratio of the natural graphite particles with a particle size of -45 μm, the natural graphite particles with a particle size of 45 μm to 75 μm, the natural graphite particles with a particle size of 75 μm to 270 μm, and the natural graphite particles with a particle size of +270 μm is 0.5 to 1:1 to 1.5:2.5 to 3.5:4 to 6.

[0010] Optionally, the process of puffing the mixture with concentrated sulfuric acid and hydrogen peroxide includes: mixing concentrated sulfuric acid and hydrogen peroxide with the mixture evenly, allowing it to stand at room temperature for 3-6 hours, and then washing, filtering, and drying it.

[0011] Optionally, the weight-to-volume ratio of the mixture to concentrated sulfuric acid and hydrogen peroxide is 1 g:(10~20) mL:(2~5) mL.

[0012] Optionally, the process of puffing the mixture with concentrated sulfuric acid and hydrogen peroxide includes: mixing and stirring the mixture with concentrated sulfuric acid and hydrogen peroxide for 0.5-1.5 h, then washing, filtering and drying the mixture, and then transferring it to a sealed container for high-temperature puffing to obtain porous graphite blocks.

[0013] Optionally, the weight-to-volume ratio of the mixture to concentrated sulfuric acid and hydrogen peroxide is 1 g:(4~8) mL:(0.1~0.5) mL.

[0014] Optionally, the sealed container is a graphite crucible or a corundum crucible with a lid.

[0015] Optionally, the high-temperature puffing temperature is 600~1100 ℃.

[0016] Optionally, the washing, filtering and drying process includes: surface cleaning with deionized water, transferring the filtered and collected solids to an oven, and drying at 80~120°C.

[0017] Optionally, the natural graphite particles of different preset particle sizes are prepared by a natural graphite crushing and grading process.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] This invention provides a method for preparing porous graphite blocks from graded natural graphite particles. The method includes: uniformly mixing natural graphite particles with different preset particle sizes in a certain proportion to form a mixed material; performing an expansion treatment on the mixed material using concentrated sulfuric acid and hydrogen peroxide; and washing, filtering, and drying the resulting material to obtain porous graphite blocks. The different preset particle sizes of the natural graphite particles include: natural graphite particles with a particle size of -45 μm, natural graphite particles with a particle size of 45 μm to 75 μm, natural graphite particles with a particle size of 75 μm to 270 μm, and natural graphite particles with a particle size of +270 μm.

[0020] The method for preparing porous graphite blocks from graded natural graphite particles provided by this invention can achieve the preparation of porous graphite blocks with certain mechanical strength and uniform pores, thereby improving the adsorption capacity and recycling performance of low-viscosity oils or organic solvents. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A flowchart of a method for preparing porous graphite blocks from graded natural graphite particles according to an embodiment of the present invention is shown.

[0023] Figure 2 This illustrates a porous graphite block provided in an embodiment of the present invention;

[0024] Figure 3 Another porous graphite block provided by an embodiment of the present invention is shown. Detailed Implementation

[0025] 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention. Furthermore, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of the present invention.

[0026] Specific experimental steps or conditions are not specified in the embodiments; they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products. Furthermore, the accompanying drawings are merely illustrative diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0027] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of this specification.

[0028] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0029] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] This invention provides a method for preparing porous graphite blocks from graded natural graphite particles. Figure 1 A flowchart illustrating the method for preparing porous graphite blocks from graded natural graphite particles according to an embodiment of the present invention is shown, as follows: Figure 1 As shown, the method includes:

[0031] S1. Natural graphite particles with different preset particle sizes are mixed evenly in proportion to form a mixed material;

[0032] S2. The mixture is expanded using concentrated sulfuric acid and hydrogen peroxide, and the resulting material is washed, filtered and dried to obtain porous graphite blocks.

[0033] In specific implementation, the natural graphite particles of different preset particle sizes used in this invention include: natural graphite particles with a particle size of -45 μm, natural graphite particles with a particle size of 45 μm to 75 μm, natural graphite particles with a particle size of 75 μm to 270 μm, and natural graphite particles with a particle size of +270 μm. Since the particle size range of the natural graphite particles used covers -45 μm to +270 μm, these natural graphite particles of different sizes are combined and expanded into porous graphite blocks. This allows small-particle-size expanded graphite to fill the gaps between large-particle-size expanded graphite particles, thereby improving the mechanical strength and pore uniformity of the blocks, and further modifying the adsorption performance of the porous graphite blocks for low-viscosity oils and organic solvents.

[0034] In some embodiments, the mass ratio of the natural graphite particles with a particle size of -45 μm, natural graphite particles with a particle size of 45 μm to 75 μm, natural graphite particles with a particle size of 75 μm to 270 μm, and natural graphite particles with a particle size of +270 μm is 0.5 to 1:1 to 1.5:2.5 to 3.5:4 to 6. More preferred mass ratios are 0.5:1:2.5:6, 0.5:1.5:3.5:4.5, and 1:1.5:3.5:4.

[0035] In some embodiments, the present invention employs two methods to uniformly mix the above-mentioned natural graphite particles of different preset particle sizes in proportion to form a mixed material for expansion treatment. One method is a one-step room temperature expansion method, specifically using concentrated sulfuric acid and hydrogen peroxide to perform a one-step room temperature expansion treatment on the mixed material, including: after uniformly mixing concentrated sulfuric acid, hydrogen peroxide and the mixed material, standing at room temperature for 3-6 hours, washing the surface of the obtained material with deionized water, transferring the filtered and collected solids to an oven, and drying at 80-120°C to obtain porous graphite blocks. The weight-to-volume ratio of the mixed material to concentrated sulfuric acid and hydrogen peroxide is 1 g : (10~20) mL : (2~5) mL. Another method is a two-step high-temperature expansion process. Specifically, the mixed material is pretreated (mixed and stirred) with concentrated sulfuric acid and hydrogen peroxide for 0.5-1.5 h to form intercalation materials (graphite oxides) between the carbon layers of the natural graphite particles. The natural graphite particles are then surface-washed with deionized water, and the filtered solids are transferred to an oven and dried at 80~120 ℃. The dried natural graphite particles are then transferred to a sealed container and subjected to high-temperature expansion at 600~1100 ℃, with a preferred temperature of 1000 ℃. The high temperature causes the oxide layers to decompose, releasing a large amount of gas. This gas expands and further expands the graphite particles, ultimately yielding porous graphite blocks. During this process, the weight-to-volume ratio of the mixed material to concentrated sulfuric acid and hydrogen peroxide is 1 g : (4~8) mL : (0.1~0.5) mL.

[0036] Both of the above methods produce porous graphite blocks with certain mechanical strength and uniform pore size, which meets the adsorption requirements for low-viscosity oils and organic solvents. Among them, the one-step room temperature expansion method has the advantage of simple operation steps and no need for high temperature expansion, but the amount of reagents used (concentrated sulfuric acid, hydrogen peroxide) is larger than that used in the two-step high temperature expansion method.

[0037] In some implementations, the sealed container is a covered graphite crucible or a corundum crucible.

[0038] In some implementations, the washing, filtering, and drying include: surface cleaning with deionized water, transferring the filtered and collected solids to an oven, and drying at 80-120°C.

[0039] In some implementations, the natural graphite particles of different preset particle sizes are prepared by a natural graphite crushing and grading process.

[0040] To enable those skilled in the art to more clearly understand the present invention, the following embodiments will be used to describe in detail the method for preparing porous graphite blocks from graded natural graphite particles according to the present invention.

[0041] The specific implementation details of this invention are as follows:

[0042] Example 1

[0043] Natural graphite particles with particle sizes ranging from -45 μm, 45 μm to 75 μm, 75 μm to 270 μm, and +270 μm were mixed uniformly at a mass ratio of 0.5:1:2.5:6, with a total mass of 1 g. The graphite was transferred to a beaker containing 10 mL of concentrated sulfuric acid and stirred in an ice-water bath. 2 mL of hydrogen peroxide was slowly added, and stirring continued for 0.5 h. The mixture was then allowed to stand at room temperature for 3 h. After washing to remove acid and filtering, the mixture was dried at 100 ℃ to obtain porous graphite blocks. (See attached image) Figure 2 .

[0044] Example 2

[0045] Natural graphite particles with particle sizes ranging from -45 μm, 45 μm to 75 μm, 75 μm to 270 μm, and +270 μm were mixed uniformly at a mass ratio of 1:1.5:3.5:4, with a total mass of 1 g. The graphite was transferred to a beaker containing 10 mL of concentrated sulfuric acid and stirred in an ice-water bath. 2 mL of hydrogen peroxide was slowly added and stirring was continued for 0.5 h. The mixture was then allowed to stand at room temperature for 3 h. After washing with water to remove acid and filtering, the mixture was dried at 100 ℃ to obtain porous graphite blocks.

[0046] (The process in this embodiment is the same as in Embodiment 1. The difference is that the graphite particles of different particle size ranges are mixed in a mass ratio of 1:1.5:3.5:4.)

[0047] Example 3

[0048] Natural graphite particles with particle sizes ranging from -45 μm, 45 μm to 75 μm, 75 μm to 270 μm, and +270 μm were mixed uniformly at a mass ratio of 0.5:1:2.5:6, with a total mass of 1 g. The graphite was transferred to a beaker containing 20 mL of concentrated sulfuric acid and stirred in an ice-water bath. 5 mL of hydrogen peroxide was slowly added and stirring was continued for 0.5 h. The mixture was then allowed to stand at room temperature for 3 h. After washing with water to remove acid and filtering, the mixture was dried at 100 ℃ to obtain porous graphite blocks.

[0049] (The process in this example is the same as in Example 1. The difference is that the amounts of sulfuric acid and hydrogen peroxide used are 20 mL and 5 mL, respectively.)

[0050] Example 4

[0051] Natural graphite particles with particle sizes ranging from -45 μm, 45 μm to 75 μm, 75 μm to 270 μm, and +270 μm were mixed uniformly at a mass ratio of 0.5:1.5:3.5:4.5, with a total mass of 1 g. The graphite was transferred to a beaker containing 4 mL of concentrated sulfuric acid and stirred under an ice-water bath. 0.1 mL of hydrogen peroxide was slowly added, and stirring continued for 0.5 h. After washing with water to remove acid, filtration, and drying at 100 °C, expandable graphite was obtained. The expandable graphite was placed in a covered graphite crucible and expanded in a muffle furnace at 1000 °C to obtain porous graphite blocks. (See...) Figure 3 .

[0052] Example 5

[0053] Natural graphite particles with particle sizes ranging from -45 μm, 45 μm to 75 μm, 75 μm to 270 μm, and +270 μm were mixed uniformly at a mass ratio of 1:1.5:3.5:4, with a total mass of 1 g. The graphite was transferred to a beaker containing 4 mL of concentrated sulfuric acid and stirred under an ice-water bath. 0.1 mL of hydrogen peroxide was slowly added, and stirring was continued for 0.5 h. After washing with water to remove acid, filtration, and drying at 100 °C, expandable graphite was obtained. The expandable graphite was placed in a covered graphite crucible and expanded in a muffle furnace at 1000 °C to obtain porous graphite blocks.

[0054] (This embodiment is the same as the process in Implementation 4. The difference is that the graphite particles of different particle size ranges are mixed in a mass ratio of 1:1.5:3.5:4.)

[0055] Example 6

[0056] Natural graphite particles with particle sizes ranging from -45 μm, 45 μm to 75 μm, 75 μm to 270 μm, and +270 μm were mixed uniformly at a mass ratio of 0.5:1.5:3.5:4.5, with a total mass of 1 g. The graphite was transferred to a beaker containing 8 mL of concentrated sulfuric acid and stirred under an ice-water bath. 0.5 mL of hydrogen peroxide was slowly added, and stirring was continued for 0.5 h. After washing with water to remove acid, filtration, and drying at 100 °C, expandable graphite was obtained. The expandable graphite was placed in a covered graphite crucible and expanded in a muffle furnace at 1000 °C to obtain porous graphite blocks.

[0057] (The process in this example is the same as in Example 4. The difference is that the amounts of sulfuric acid and hydrogen peroxide used are 8 mL and 0.5 mL, respectively.)

[0058] Example 7

[0059] Natural graphite particles with particle sizes ranging from -45 μm, 45 μm to 75 μm, 75 μm to 270 μm, and +270 μm were mixed uniformly at a mass ratio of 0.5:1.5:3.5:4.5, with a total mass of 1 g. The graphite was transferred to a beaker containing 4 mL of concentrated sulfuric acid and stirred under an ice-water bath. 0.1 mL of hydrogen peroxide was slowly added, and stirring was continued for 0.5 h. After washing with water to remove acid, filtration, and drying at 100 °C, expandable graphite was obtained. The expandable graphite was placed in a covered graphite crucible and expanded in a muffle furnace at 600 °C to obtain porous graphite blocks.

[0060] (This embodiment is the same as the process in Embodiment 4. The difference is that the high-temperature puffing temperature is 600 ℃.)

[0061] Comparative Example 1

[0062] 1 g of natural graphite particles with a particle size range of +270 μm was transferred to a beaker containing 4 mL of concentrated sulfuric acid. The mixture was stirred in an ice-water bath, and 0.1 mL of hydrogen peroxide was slowly added followed by continuous stirring for 0.5 h. After washing with water to remove acid, filtration, and drying, expandable graphite was obtained. The expandable graphite was placed in a covered graphite crucible and expanded in a muffle furnace at 1000 ℃ to obtain porous graphite blocks.

[0063] Comparative Example 2

[0064] 1 g of natural graphite particles with a particle size range of -45 μm was transferred to a beaker containing 4 mL of concentrated sulfuric acid. The mixture was stirred in an ice-water bath, and 0.1 mL of hydrogen peroxide was slowly added followed by continuous stirring for 0.5 h. After washing with water to remove acid, filtration, and drying, expandable graphite was obtained. The expandable graphite was placed in a covered graphite crucible and expanded in a muffle furnace at 1000 ℃ to obtain porous graphite blocks.

[0065] Experimental Example

[0066] Meanwhile, the porous graphite blocks prepared in Examples 1-7 and Comparative Examples 1-2 were placed in beakers containing diesel fuel for 10 minutes, removed and weighed. The adsorption capacity of diesel fuel was calculated based on the mass difference before and after oil absorption. The test results are shown in Table 1.

[0067] Table 1 Diesel adsorption capacity of porous graphite blocks

[0068]

[0069] As can be seen from the test data in Table 1, the porous graphite blocks prepared by the graded natural graphite particles provided in this embodiment of the invention exhibit a higher diesel adsorption capacity compared with the graphite blocks in the comparative example. This indicates that the present invention effectively fills the gaps formed between large-particle-size expanded graphite particles by matching the particle size of natural graphite particles with small-particle-size expanded graphite particles, thereby improving the uniformity of the pores of the graphite blocks and thus improving the adsorption performance of low-viscosity oil.

[0070] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0071] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0072] The method for preparing porous graphite blocks from graded natural graphite particles provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for producing a porous graphite block from a fractionated natural graphite particle, characterized by, The method comprises: uniformly mixing natural graphite particles with different preset particle sizes in proportion to form a mixed material; After mixing and stirring the concentrated sulfuric acid, hydrogen peroxide and the mixed material for 0.5-1.5 h, washing, filtering and drying treatment are performed, and then the mixed material is transferred to a sealed container, and a porous graphite block is obtained after high-temperature puffing; the temperature of the high-temperature puffing is 600-1100℃; The natural graphite particles with different preset particle sizes include natural graphite particles with a particle size of-45 μm, natural graphite particles with a particle size of 45 μm-75 μm, natural graphite particles with a particle size of 75 μm-270 μm and natural graphite particles with a particle size of +270 μm. The porous graphite block is used for adsorbing low-viscosity oil or organic solvents, so as to improve the adsorption capacity and recycling performance of the porous graphite block for low-viscosity oil or organic solvents. The mass ratio of the natural graphite particles with a particle size of-45 μm, the natural graphite particles with a particle size of 45 μm-75 μm, the natural graphite particles with a particle size of 75 μm-270 μm and the natural graphite particles with a particle size of +270 μm is 0.5-1:1-1.5:2.5-3.5:4-6.

2. The method of producing a porous graphite bulk body from the classified natural graphite particles according to claim 1, characterized by, After mixing and stirring the concentrated sulfuric acid, hydrogen peroxide and the mixed material for 0.5-1.5 h, the mixed material is statically placed at room temperature for 3-6 h, and then washing, filtering and drying treatment are performed.

3. The method of producing a porous graphite bulk body from the classified natural graphite particles according to claim 1, characterized by, The weight-to-volume ratio of the mixed material, the concentrated sulfuric acid and the hydrogen peroxide is 1 g:(10-20) mL:(2-5) mL.

4. The method of producing a porous graphite bulk body from the classified natural graphite particles according to claim 1, characterized by, The weight-to-volume ratio of the mixed material, the concentrated sulfuric acid and the hydrogen peroxide is 1 g:(4-8) mL:(0.1-0.5) mL.

5. The method of producing a porous graphite bulk body from the classified natural graphite particles according to claim 1, characterized by, The sealed container is a graphite crucible or a corundum crucible with a cover.

6. The method of producing a porous graphite bulk body from the classified natural graphite particles according to claim 1 or 2, characterized by, The washing, filtering and drying treatment includes surface cleaning with deionized water, transferring the collected solid material to an oven and drying at 80-120℃.

7. The method of claim 1, wherein the porous graphite bulk body is prepared from the hierarchical natural graphite particles. The natural graphite particles with different preset particle sizes are prepared by a natural graphite crushing and grading process.

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