CN-122010110-A - Low-energy-consumption green expandable graphite processing method

CN122010110ACN 122010110 ACN122010110 ACN 122010110ACN-122010110-A

Abstract

The invention relates to the field of expandable graphite preparation, in particular to a low-energy-consumption green expandable graphite processing method, which comprises the following steps of firstly carrying out microwave irradiation treatment on natural crystalline flake graphite to generate thermal stress cracks; and then taking the treated graphite as an anode, and placing the anode in a composite electrolyte for constant-pressure electrochemical intercalation treatment. The electrification duration and the initial voltage are regulated in real time by detecting the sedimentation speed and the interlayer spacing of the intercalated graphite. And then, placing the intercalated graphite reaching the standard into an organic solvent for solvent replacement and auxiliary ultrasonic treatment to obtain vermicular precursor graphite, and adjusting the preheating power of the microwave expansion equipment according to the turbidity of the replaced solution. Finally, the expansion duration is determined by detecting the specific surface area of the precursor graphite. The invention solves the problem of unstable product quality caused by the easy excessive oxidation of the low-energy-consumption green expandable graphite electrolyte in the prior art by detecting the process parameter adjusting procedure of the expandable graphite.

Inventors

LI GUANG
WANG ZHIJUN

Assignees

包头市华诚石墨材料有限责任公司

Dates

Publication Date: 20260512
Application Date: 20260311

Claims (10)

1. The low-energy-consumption green expandable graphite processing method is characterized by comprising the following steps of: carrying out microwave irradiation treatment on the natural crystalline flake graphite to obtain thermal stress crack crystalline flake graphite; selecting a unit volume of the thermal stress crack crystalline flake graphite as an anode, and placing the anode in a composite electrolyte for constant-pressure electrochemical intercalation test to obtain test intercalation graphite; wherein, the components of the composite electrolyte comprise persulfate intercalation agents, carboxylic acid complexing agents and deionized water; Placing the test intercalated graphite sample in an absolute ethanol solution, detecting the sedimentation rate of the test intercalated graphite and the interlayer spacing of the intercalated graphite, and adjusting the electrifying duration and the initial voltage of constant-voltage electrochemical intercalation treatment according to the sedimentation rate and the interlayer spacing; Taking the thermal stress crack crystalline flake graphite as an anode, and placing the anode in a composite electrolyte to perform constant-voltage electrochemical intercalation treatment according to the electrifying duration and the initial voltage so as to obtain intercalated graphite; Placing the intercalated graphite into an organic solvent for solvent replacement treatment, and performing auxiliary ultrasonic treatment to obtain vermicular precursor graphite; Determining the preheating power of the microwave expansion equipment according to the turbidity of the solution after the solvent replacement treatment; Detecting the specific surface area of the expandable graphite primary product, and determining the expansion duration of the microwave expansion equipment according to the specific surface area; and placing the precursor graphite in a microwave expansion device, and performing microwave expansion under the protection of inert gas to obtain an expandable graphite finished product.
2. The method for processing low-energy-consumption green expandable graphite according to claim 1, wherein said adjusting the energization time period of said constant-pressure electrochemical intercalation process according to said sedimentation velocity and said interlayer spacing comprises, Comparing the sedimentation velocity with a preset sedimentation velocity threshold, and comparing the interlayer spacing with a preset interlayer spacing threshold; if the sedimentation velocity is smaller than a preset sedimentation velocity threshold value, determining that the sulfate intercalation agent generates self-decomposition oxygen production phenomenon, and reducing the electrifying duration of the constant-pressure electrochemical intercalation treatment according to the difference value between the preset sedimentation velocity threshold value and the sedimentation velocity; If the interlayer spacing is smaller than a preset interlayer spacing threshold, the intercalation reaction is judged to be insufficient, intercalation agent molecules cannot fully enter the graphite layers, and the initial voltage of the constant-voltage electrochemical intercalation processing of the next batch is increased according to the difference value between the preset interlayer spacing threshold and the interlayer spacing.
3. The method of claim 2, wherein the magnitude of the decrease in the duration of the constant voltage electrochemical intercalation process is directly related to the difference between the predetermined sedimentation velocity threshold and the sedimentation velocity.
4. The method of claim 3, wherein the initial voltage increase of the constant voltage electrochemical intercalation process is positively related to the difference between the predetermined interlayer spacing threshold and the interlayer spacing.
5. The method for processing low-energy-consumption green expandable graphite according to claim 4, wherein the determining the preheating power of the microwave expansion device according to the turbidity of the solution after the solvent substitution treatment comprises, Comparing the solution turbidity with a preset solution turbidity threshold; If the solution turbidity is smaller than a preset solution turbidity threshold, determining that the situation that the interlayer impurity content is higher occurs, and increasing the preheating power of the microwave expansion device according to the difference value between the preset solution turbidity threshold and the solution turbidity; and if the solution turbidity is greater than or equal to a preset solution turbidity threshold, determining that the solvent replacement treatment meets the standard, wherein the preheating power of the microwave expansion equipment is preset.
6. The method for processing low-energy-consumption green expandable graphite according to claim 5, wherein the turbidity of the solution is a value indicative of the scattering degree of the suspended particles on light in the mixed system after the completion of the solvent substitution treatment.
7. The method of claim 6, wherein the magnitude of the increase in preheating power is directly related to the difference between the predetermined solution turbidity threshold and the solution turbidity.
8. The method for processing low energy consumption green expandable graphite according to claim 7, wherein said determining the expansion duration of the microwave expansion device based on said specific surface area comprises, Comparing the specific surface area with a preset specific surface area threshold value; If the specific surface area is smaller than a preset specific surface area threshold value, determining that the expansion potential of an interlayer structure of the precursor graphite is limited, and prolonging the expansion duration of the microwave expansion equipment according to the difference value between the preset specific surface area threshold value and the specific surface area; And if the specific surface area is larger than or equal to a preset specific surface area threshold value, judging that the interlayer structure of the precursor graphite is good in development, wherein the expansion duration of the microwave expansion equipment is a preset expansion duration.
9. The method of claim 8, wherein the expansion duration is extended by an amount that is directly related to the difference between the predetermined specific surface area threshold and the specific surface area.
10. The method for processing low-energy-consumption green expandable graphite according to claim 9, wherein the organic solvent for the solvent replacement treatment is one of absolute ethyl alcohol, acetone and isopropyl alcohol, and the volume ratio of the organic solvent to the intercalated graphite is 4:1.

Description

Low-energy-consumption green expandable graphite processing method Technical Field The invention relates to the technical field of expandable graphite preparation, in particular to a low-energy-consumption green expandable graphite processing method. Background The expandable graphite is an important graphite deep processing product, and is widely applied to the fields of sealing materials, adsorption materials, energy storage materials, flame-retardant fireproof materials and the like by virtue of the rich lamellar structure, adjustable interlayer spacing and good chemical stability. The expanded graphite is usually prepared by rapidly expanding natural crystalline flake graphite after intercalation treatment to form a graphite interlayer compound under high temperature or microwave irradiation, and the expansion ratio is one of core indexes for evaluating the quality of products. At present, the preparation methods of expandable graphite are mainly divided into two types, namely a chemical method and an electrochemical method. The traditional chemical oxidation method generally adopts strong oxidizing acid such as potassium permanganate, concentrated sulfuric acid, concentrated nitric acid or perchloric acid to carry out oxidation intercalation treatment on graphite. However, the method has the defects that on one hand, the use of strong oxidizing acid causes serious potential safety hazards in the production process, a large amount of acid-containing wastewater is generated, the environmental load is large, the development requirement of the current green chemical industry is not met, on the other hand, the traditional process has higher requirement on the particle size of graphite raw materials, the intercalation process is unstable, the fluctuation of expansion rate of the product is large, the consistency among batches is poor, and the stable requirement of the high-performance expandable graphite in the high-end application field is difficult to meet. To overcome the environmental and safety problems of the conventional chemical methods, electrochemical intercalation methods have been proposed and developed. According to the method, graphite is used as an anode, and oxidation intercalation treatment is carried out in electrolyte, so that the use of a strong oxidant can be reduced. However, the existing electrochemical method still has the problem of low intercalation efficiency, and the traditional electrolyte systems such as sulfuric acid, nitric acid and the like are mostly used, so that the problem of green technology cannot be fundamentally solved. In addition, the technological parameters in the electrochemical treatment process are set empirically, the process of adjusting according to the intermediate product state is lacking, the intercalation effect is unstable, and the product quality of the subsequent expansion process is directly affected. Disclosure of Invention Therefore, the invention provides a processing method of low-energy-consumption green expandable graphite, which is used for solving the problem of unstable product quality caused by excessive oxidation of low-energy-consumption green expandable graphite electrolyte in the prior art. The problems of unstable expansion multiplying power, high process energy consumption, large environmental load and lack of a process regulation mechanism in the prior art are solved. In order to achieve the above object, the present invention provides a low-energy-consumption green expandable graphite processing method, comprising: carrying out microwave irradiation treatment on the natural crystalline flake graphite to obtain thermal stress crack crystalline flake graphite; selecting a unit volume of the thermal stress crack crystalline flake graphite as an anode, and placing the anode in a composite electrolyte for constant-pressure electrochemical intercalation test to obtain test intercalation graphite; wherein, the components of the composite electrolyte comprise persulfate intercalation agents, carboxylic acid complexing agents and deionized water; Placing the test intercalated graphite sample in an absolute ethanol solution, detecting the sedimentation rate of the test intercalated graphite and the interlayer spacing of the intercalated graphite, and adjusting the electrifying duration and the initial voltage of constant-voltage electrochemical intercalation treatment according to the sedimentation rate and the interlayer spacing; Taking the thermal stress crack crystalline flake graphite as an anode, and placing the anode in a composite electrolyte to perform constant-voltage electrochemical intercalation treatment according to the electrifying duration and the initial voltage so as to obtain intercalated graphite; Placing the intercalated graphite into an organic solvent for solvent replacement treatment, and performing auxiliary ultrasonic treatment to obtain vermicular precursor graphite; Determining the preheating power of the microwave