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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-containing substances such as concentrated sulfuric acid are often used as the main oxidizing intercalation substance. Small, so that expandable graphite is severely restricted in mechanical seals

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] A kind of preparation method of expandable graphite, adopts perchloric acid: phosphoric acid mass ratio is 1: 3 mixed acid solution, under the existence of solid strong oxidant potassium permanganate, oxidizes natural phosphorus flake graphite, the temperature during oxidation is 90 ℃, The oxidation time is 120min, and the mass ratio of the natural phosphorus flake graphite:perchloric acid and phosphoric acid mixed acid solution:solid strong oxidant is 1:8:0.6. The mass total concentration in the mixed acid solution of perchloric acid and phosphoric acid is 85%. Centrifugal deacidification after oxidizing natural phosphorus flake graphite, and further impregnating and intercalating the oxidized natural phosphorus flake graphite with organic acid formic acid, the mass ratio of formic acid: natural phosphorus flake graphite is 1:1, after washing with water, Bake until the water content is less than 1%, to prepare expandable graphite.

Embodiment 2

[0015] A kind of preparation method of expandable graphite, adopts perchloric acid: phosphoric acid mass ratio is 1: 0.05 mixed acid solution, under the existence of solid strong oxidant potassium permanganate, oxidizes natural phosphorus flake graphite, the temperature during oxidation is 10 ℃, The oxidation time is 5 minutes, and the mass ratio of the natural phosphorus flake graphite:perchloric acid and phosphoric acid mixed acid solution:solid strong oxidant is 1:0.5:0.02. The mass total concentration in the mixed acid solution of perchloric acid and phosphoric acid is 60%. Centrifugal deacidification after oxidizing natural phosphorus flake graphite, and then use organic acid formic acid, acetic acid, propionic acid mixed acid to further impregnate and intercalate the oxidized natural phosphorus flake graphite, the formic acid, acetic acid, propionic acid mixed acid: natural phosphorus flake The mass ratio of the graphite is 0.01:1, and after being washed with water, the ...

Embodiment 3

[0017] A kind of preparation method of expandable graphite, adopt perchloric acid: phosphoric acid mass ratio is 1: 1.5 mixed acid solution, under the existence of solid strong oxidant potassium permanganate, oxidize natural phosphorus flake graphite, the temperature during oxidation is 80 ℃, The oxidation time is 60 minutes, and the mass ratio of the natural phosphorus flake graphite:perchloric acid and phosphoric acid mixed acid solution:solid strong oxidant is 1:5:0.1. The mass total concentration in the mixed acid solution of perchloric acid and phosphoric acid is 70%. Centrifugal deacidification after oxidizing natural phosphorus flake graphite, then further impregnating and intercalating the oxidized natural phosphorus flake graphite with an organic acid mixed with acetic anhydride and oxalic acid, the organic acid mixed with acetic anhydride and oxalic acid: the quality of natural phosphorus flake graphite The ratio is 0.05:1, and after washing with water, it is baked a...

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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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