Expandable graphite preparation device and electrochemical intercalation method thereof

Abstract

The invention discloses an expandable graphite preparation device and an electrochemical intercalation method thereof, and belongs to the field of crystalline flake graphite electrochemical intercalation. The device comprises a wrapping pocket, an electrode, a direct current voltage-stabilizing and current-stabilizing power supply, a quick plug connector, a cross beam, an electrolytic cell, a circulating cooling device, a thermocouple, a first servo motor, a support frame and a second servo motor. The method comprises the steps of preparation of a chemical electrolyte, bag filling of natural crystalline flake graphite, electrode assembly and electrochemical intercalation preparation, electrochemical intercalation treatment, and treatment of an intercalation compound. According to the method, natural crystalline flake graphite can be efficiently intercalated to prepare expandable graphite, the prepared expandable graphite does not generate smoke and irritant gas in the microwave expansion and high-temperature expansion processes, and the expansion ratio can reach 200-300 mg / L. The problems of production safety and environmental pollution related to expandable graphite preparation can be solved from the source, large-scale preparation and engineering application of expandable graphite can be actively promoted, and the market application prospect is wide.

Description

technical field [0001] The invention relates to the field of electrochemical intercalation of flake graphite, in particular to an expandable graphite preparation device and an electrochemical intercalation method thereof. Background technique [0002] Since the carbon atoms of natural flake graphite have a hexagonal network planar overlapping structure, and the layers are combined with weak van der Waals force, in the process of preparing expandable graphite, atoms, ions, and molecules are inserted between the graphite layers to form Graphite interlayer compound, that is, the preparation of expandable graphite. Under the action of high temperature or microwave irradiation of expandable graphite, most of the compounds between the graphite layers will decompose into small molecular gases and escape in an instant, and at the same time, the graphite layer will expand tens or even hundreds of times in the direction of the c-axis, thus making Get expanded graphite. Expanded grap...

AI Technical Summary

Problems solved by technology

However, this technology has hidden dangers in production safety and potential environmental hazards, so its engineering application is not optimistic

The traditional electrochemical method is to prepare an electrolyte solution with strong oxidizing acids such as sulfuric acid and nitric acid, as well as chemicals such as acetic acid and hydrogen peroxide, place natural flake graphite in an electrolytic cell, and pass a pulse current through two electrodes, thereby Anodic oxidation intercalation treatment is carried out, but it has the technical defect of low intercalation efficiency, and the potential environmental hazards have not been eliminated

Patent CN106744923A mentions a preparation method of expandable graphite with low sulfur content, which stirs and mixes the aqueous solution of water-soluble peroxygen compound and natural flake graphite, then adds concentrated sulfuric acid and continues to stir, then filters, washes, and dries to prepare The initial material of expanded graphite, and then stir and mix this initial material with aqueous hydrogen peroxide solution, and add an acidic phosphorus-containing compound to continue impregnating, then filter, wash with water, and dry to obtain expandable graphite. The sulfur content is less than 2%. The volume can reach 240mg / L, but this preparation process uses concentrated sulfuric acid as an intercalation agent. Even if the product has a low sulfur content, sulfuric acid waste liquid is generated during the production process, which has a high production risk, and sulfuric acid mist will be generated during the subsequent expansion process. Deteriorating the atmospheric environment, its environmental unfriendliness has obvious defects

The patent with the publication number CN109592678A mentions a method for the preparation of sulfur-free high-magnification expandable graphite. The preparation process uses high-purity flake graphite as raw material, adding potassium permanganate, sodium nitrate, and acetic acid. Chemical reaction, after the reaction is complete, wash, filter, and dry to produce sulfur-free high-magnification expandable graphite. This patent uses potassium permanganate and sodium nitrate as oxidants, and there is a risk of explosion, and the waste liquid generated during the production process is difficult to handle , has great potential harm to the ecological environment

The patent with the publication number CN108862271A mentions a method for preparing expandable graphite with an optimized ratio of intercalation agent. The preparation process uses natural flake graphite as raw material, potassium permanganate as oxidant, sulfuric acid as intercalation agent, Ferric chloride is used as an auxiliary intercalation agent to prepare expandable graphite. This patent uses sulfuric acid as an intercalation agent. Sulfuric acid waste liquid will also be generated during the production process. The production risk is relatively large, and sulfuric acid mist will be generated during the subsequent expansion process, which will deteriorate the atmosphere. environment, its environmentally unfriendly defect is significant

The patent of publication number CN106629703A mentions a preparation method of a high-expansibility low-sulfur graphite intercalation compound. The preparation process includes heating the natural flake graphite in a water bath, heating the intercalation agent to soak the natural flake graphite, and then adding an oxidant to react to obtain a reaction product , the reaction product is washed with water, filtered, and dried to obtain acidified graphite, and then an oxidizing agent is added to react to obtain the product, and the product is washed with water, filtered, and dried to obtain expandable graphite. The patent uses potassium permanganate, potassium dichromate, concentrated nitric acid, high One of the chloric acids is used as an oxidant, and the waste liquid generated during the production process is difficult to handle, and it also has great potential harm to the ecological environment

At present, the preparation process of expandable graphite is relatively mature, but the current process needs to use a large amount of strong acid and strong oxidant, which poses safety hazards in chemical transportation, storage and use, and does not meet clean production, green preparation and ecological environmental protection. general requirements, and then its engineering application universality is poor

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