Method for producing graphite
By mixing carbon-based materials such as leaves and moss with waste paper, and after soaking, crushing, adding adhesives, pressing and high-temperature graphitization, the problems of high production costs and complex production processes of existing high-temperature thermal insulation materials are solved, and graphite materials with high cost efficiency and excellent mechanical properties are achieved.
Patent Information
- Application Number
- CN202280098981.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-08-10
- Filing Date
- 2022-08-24
- Publication Date
- 2025-03-21
AI Technical Summary
The production cost of existing high-temperature insulation materials is relatively high and the production process is complex, making it difficult to meet the needs of industrial production for renewable, cheap and simple production processes.
Carbon-based materials such as leaves and moss are mixed with waste paper and other raw materials, and after soaking, crushing, adhesive addition, pressing and high-temperature graphitization, cost-effective graphite materials are produced.
The use of renewable and cheap raw materials to produce high-temperature insulation materials is realized, which simplifies the production process, reduces costs, and improves the mechanical properties of graphite materials.
Abstract
Description
Technical Field
[0001] The invention relates to a method for producing graphite. The graphite produced by the method is used as a high-temperature heat insulating material or a filter material or other components in the form of a block or a sheet. Background Art
[0002] In industrial production, high temperature insulation materials are used whenever the production process is carried out at high temperatures and it is not desired to radiate the high temperature into the environment to avoid unnecessary energy losses. Since high temperature insulation materials are used in large quantities, it is very advantageous to use renewable and particularly cheap raw materials as the starting materials for the production of high temperature insulation materials.
[0003] In addition, the production process should be as simple as possible and have as few production steps as possible to reduce overall costs. Summary of the invention
[0004] The object of the present invention is to provide a cost-effective method for producing graphite for use as a high-temperature thermal insulation material or filter material or construction material, in which particularly cheap and renewable raw materials and waste paper can be used as starting materials.
[0005] According to the present invention, the production method is as follows:
[0006] - preparing a base material in the form of a mixture of carbon-based materials, the base material in the form of a mixture of carbon-based materials containing at least one of the following raw materials: leaves, moss or other similar materials, such as grass, corn leaves or sawdust, waste paper or natural fibers, and mixed with these raw materials in any proportion;
[0007] - The mixture is then soaked in a solvent for a long time and then crushed;
[0008] - Add a binder to the mixture until it becomes a substantially homogeneous paste;
[0009] - pressing the mixture to substantially remove the solvent until a sufficiently stable pressed product with a sufficiently low solvent content is obtained;
[0010] - Drying the pressed product until the remaining solvent has completely evaporated;
[0011] -Put the pressed product into a high temperature furnace, in an oxygen-free environment filled with inert gas or in a vacuum, and at a temperature of >2000°C, to graphitize it into a block.
[0012] The first embodiment of the present invention uses water as the solvent.
[0013] According to an alternative, polyacrylonitrile (PAN) dissolved in dimethyl sulfoxide (DMSO) can be used as a solvent and a binder. However, in this case, the pressed product needs to be soaked in water to polymerize the polyacrylonitrile and then dried.
[0014] The mixture can also be pressed into a pressed product by isostatic pressing.
[0015] Next during the comminution process, a water-soluble binder is added to the mixture to adjust its density, the most suitable binder being syrup.
[0016] Furthermore, wheat starch may also be added to the mixture in paste form to adjust the density of the final product.
[0017] According to another embodiment of the present invention, the pressed product may be dried at high temperature in a stabilization step before being subjected to high temperature treatment.
[0018] Finally, in a further processing step, the refractory graphitized block can be surface-processed in a mechanical processing step to produce a standardized component.
[0019] Furthermore, the temperature at which graphitization is performed can be as high as 3000°C.
[0020] In order to better enable the produced graphite blocks or graphite sheets to be machined, such as milling or turning, it is advantageous to impregnate them to thicken them to a density of <1 g / cm 3 Phenolic resins, phosphates or bitumen can be used for impregnation.
[0021] The impregnated graphite can then be regraphitized and this process can be repeated multiple times.
[0022] This makes it possible to produce cost-effective graphite components with improved mechanical properties, which are suitable for use as filter media or other components in the form of blocks or sheets.
[0023] The present invention will be described in more detail below with reference to an embodiment. DETAILED DESCRIPTION
[0024] In order to produce graphitized high-temperature insulation materials, filter materials or building materials in any shape from low-cost starting materials, it is first necessary to produce a base material in the form of a carbon-based material mixture.
[0025] The base material contains at least one of the following raw materials: leaves, moss or other similar materials, such as grass, corn leaves or sawdust, waste paper or natural fibers, and is mixed from these raw materials in any proportion.
[0026] The mixture is then soaked in a solvent (e.g., water) for a long time, then mechanically crushed, and then a binder is added to the crushed mixture until it is mixed into a substantially uniform paste-like mixture during stirring, wherein crushing is a feasible step, but not necessarily required. Depending on the materials used, the mixture may need to be soaked for 1 hour to several days.
[0027] The mixture is then pressed to remove most of the solvent until a pressed product is stable enough and has a low enough solvent content to be easily handled, and then the pressed product is placed in an air-filled oven or dryer to dry until the remaining solvent has completely evaporated. It is important to ensure that there are no solvent residues in the pressed product, because the gases released by the solvent residues during the subsequent high-temperature processing may damage the pressed product.
[0028] Finally, the pressed product is placed in a high-temperature furnace, in an oxygen-free environment filled with inert gas or in a vacuum, and at a temperature of >2000°C, to be graphitized into a block material, wherein the graphitization temperature can reach up to 3000°C.
[0029] As a precaution, the pressed product can be dried at elevated temperature in an additional stabilization step before being subjected to the high-temperature treatment.
[0030] The graphite block can then be divided into the desired building components by mechanical processing.
[0031] An alternative is to replace water with polyacrylonitrile (PAN) dissolved in dimethyl sulfoxide (DMSO) as both a solvent and a binder. However, in this case, the pressed product needs to be soaked in water to polymerize the polyacrylonitrile and then dried.
[0032] The mixture can also be pressed into pressed articles by isostatic pressing.
[0033] Furthermore, during the crushing process, a water-soluble binder can be added to the mixture of carbon-based materials to adjust its density, among which syrup is the most suitable binder.
[0034] An alternative or additional way is to add wheat starch to the mixture in paste form in order to adjust the density of the final product.
[0035] Finally, in a further processing step, the refractory graphitized block can be surface-processed in a mechanical processing step to produce a standardized component.
[0036] In order to better enable the produced graphite blocks or graphite sheets to be machined, such as milling or turning, it is advantageous to impregnate them to thicken them to a density of <1 g / cm 3to a certain extent, where phenolic resins, phosphates or bitumen can be used for impregnation.
[0037] The impregnated graphite can then be regraphitized and this process can be repeated multiple times.
[0038] The method of the present invention can produce cost-effective graphite parts with improved mechanical properties, suitable for use as high temperature insulation materials or filter materials or other components in the form of blocks or sheets.
Claims
1. A method for producing graphite, wherein the produced graphite is used as a high-temperature insulation material or a filter material or other component in the form of a block or sheet, characterized in that: - preparing a base material in the form of a mixture of carbon-based materials in any proportion of the raw materials, the base material in the form of a mixture of carbon-based materials containing at least one of the following raw materials: leaves, moss or other similar materials, such as grass, corn leaves or sawdust, waste paper or natural fibers; - The mixture is then soaked in a solvent for a long time and then crushed; - Add a binder to the mixture until it becomes a substantially homogeneous paste; - pressing the mixture to substantially remove the solvent until a sufficiently stable pressed product with a sufficiently low solvent content is obtained; - Drying the pressed product until the remaining solvent has completely evaporated; -Put the pressed product into a high temperature furnace, in an oxygen-free environment filled with inert gas or in a vacuum, and at a temperature of >2000°C, to graphitize it into a block material.
2. The method according to claim 1, characterized in that: Water was used as the solvent.
3. The method according to claim 1, characterized in that: Polyacrylonitrile (PAN) dissolved in dimethyl sulfoxide (DMSO) was used as solvent and binder.
4. The method according to claim 3, characterized in that: The pressed product is immersed in water to polymerize the polyacrylonitrile.
5. The method according to claim 1, characterized in that: The mixture was pressed into a pressed product by isostatic pressing.
6. The method according to claim 1, characterized in that: During the comminution process, a water-soluble binder is added to the mixture to influence its density.
7. The method according to claim 6, characterized in that: Use syrup as a binder.
8. The method according to claim 1, characterized in that: Wheat starch is added to the mixture in the form of a paste to adjust the density of the final product.
9. The method according to any one of claims 1 to 8, characterized in that: Prior to the high temperature treatment, the pressed product is dried at high temperature in a stabilization step.
10. The method according to any one of claims 1 to 9, characterized in that: The high-temperature-resistant graphitized blocks are surface-machined in a machining step to produce standard components.
11. The method according to claim 1, characterized in that: The temperature for graphitization is up to 3000°C.
12. The method according to any one of claims 1 to 11, characterized in that: Impregnate the graphitized block material to thicken its density to <1g / cm 3 degree.
13. The method according to claim 12, characterized in that: Impregnation is done using phenolic resins, phosphates or bitumen.
14. The method according to claims 12 and 13, characterized in that: The impregnated graphite is then regraphitized and this process can be repeated multiple times.