Preparation method of expandable graphite

A technology of expanded graphite and graphite, which is applied in the chemical field, can solve problems such as small expansion volume, high expansion temperature, energy consumption, and large acid consumption, and achieve the effects of high expansion volume at low temperature, reduced environmental pollution, and stable quality

Inactive Publication Date: 2014-03-26
王伟
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traditional expandable graphite requires high expansion temperature, which is its outstanding shortcoming
In addition, in the traditional preparation process of expandable graphite, sulfur-cont

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0012] Example 1

[0013] A preparation method of expandable graphite adopts a mixed acid solution with a mass ratio of perchloric acid: phosphoric acid of 1:3, and oxidizes natural phosphorous flake graphite in the presence of a solid strong oxidant potassium permanganate, and the oxidation temperature is 90°C. The oxidation time is 120 minutes, and the mass ratio of the natural phosphorous flake graphite: the mixed acid solution of perchloric acid and phosphoric acid: the solid strong oxidant is 1:8:0.6. The total mass concentration in the mixed acid solution of perchloric acid and phosphoric acid is 85%. The natural phosphorous flake graphite is oxidized and deacidified by centrifugation. The oxidized natural phosphorous flake graphite is further impregnated and intercalated with formic acid of organic acid. The mass ratio of formic acid: natural phosphorous flake graphite is 1:1. Bake until the water content is less than 1% to prepare expandable graphite.

Example Embodiment

[0014] Example 2

[0015] A preparation method of expandable graphite adopts a mixed acid solution with a mass ratio of perchloric acid: phosphoric acid of 1:0.05, and oxidizes natural phosphorous flake graphite in the presence of a solid strong oxidant potassium permanganate at a temperature of 10°C. The oxidation time is 5 minutes, and the mass ratio of the natural phosphorous flake graphite: the mixed acid solution of perchloric acid and phosphoric acid: the solid strong oxidant is 1:0.5:0.02. The total mass concentration in the mixed acid solution of perchloric acid and phosphoric acid is 60%. After oxidizing the natural phosphorus flake graphite, it is centrifuged to deacidify, and then the oxidized natural phosphor flake graphite is further impregnated and intercalated with the mixed acid of formic acid, acetic acid and propionic acid of organic acid. The mixed acid of formic acid, acetic acid and propionic acid: natural phosphorus flake The mass ratio of graphite is 0.01:...

Example Embodiment

[0016] Example 3

[0017] A preparation method of expandable graphite adopts a mixed acid solution with a mass ratio of perchloric acid: phosphoric acid of 1:1.5 to oxidize natural phosphorous flake graphite in the presence of a solid strong oxidant potassium permanganate, and the temperature during oxidation is 80°C. The oxidation time is 60 minutes, and the mass ratio of the natural phosphorous flake graphite: the mixed acid solution of perchloric acid and phosphoric acid: the solid strong oxidant is 1:5:0.1. The total mass concentration in the mixed acid solution of perchloric acid and phosphoric acid is 70%. After oxidizing the natural phosphorous flake graphite, it is centrifuged to deacidify, and then the oxidized natural phosphorous flake graphite is further impregnated and intercalated with the organic acid mixed with acetic anhydride and oxalic acid. The mixed organic acid of acetic anhydride and oxalic acid: the quality of the natural phosphor flake graphite The ratio ...

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Abstract

A preparation method of expandable graphite comprises the following steps: oxidizing natural flake graphite for 5-120 min at 0-90 DEG C in the presence of an oxidant by using a mixed solution of perchloric acid and phosphoric acid in a mass ratio of 1:(0.05-3); deacidifying by centrifuging; further impregnating and intercalating the oxidized natural flake graphite by using organic acid; after water washing, drying at low temperature till the moisture content is less than 1% to prepare the expandable graphite. The expandable graphite is high in cryogenic expansion volume, low in energy consumption and acid consumption, sulfur-free or low in sulfur and stable in quality; the environmental pollution is reduced; the preparation method is easy to master.

Description

technical field [0001] The invention relates to the technical field of chemistry, in particular to a preparation method of expandable graphite. Background technique [0002] Expandable graphite is widely used as a mechanical seal material. The material is made by mixing high-carbon graphite with concentrated sulfuric acid and concentrated nitric acid for acidification treatment, heat treatment and then compression molding. The prepared flexible graphite is a new type of high-performance sealing material. An in situ grown nanomaterial. Compared with traditional sealing materials such as asbestos rubber, it has excellent properties such as good compressibility, resilience, self-adhesiveness, and low density, and can be used for a long time under harsh working conditions such as high temperature and high corrosion. Graphite sheets and sealing components made of it are widely used in aerospace, machinery, electronics, nuclear energy, petrochemical, electric power, shipbuild...

Claims

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Application Information

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IPC IPC(8): C01B31/04C01B32/225
Inventor 王伟
Owner 王伟
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