Method for preparing high purity graphite

A high-purity graphite and high-purity technology, applied in the field of high-purity graphite preparation, can solve problems such as complex process flow, large safety hazards, and low safety, and achieve the effects of simple process operation, high utilization value, and high safety

Active Publication Date: 2010-12-22
BEIJING GENERAL RES INST OF MINING & METALLURGY
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  • Abstract
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  • Application Information

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Problems solved by technology

Chinese patent CN1094695A discloses a high-temperature chlorination purification process for natural graphite, which adopts the method of permeating or fluidizing chlorine gas and the bulk material layer in the reaction furnace to carry out high-temperature chlorination through the action of a catalyst and a reducing agent, and removes impurities in the form of chlorides. Excluded, the obtained graphite carbon content is only 98%-99.9%, and the process is complicated, the safety hazard is great, and the further improvement effect is not obvious
The alkali fusion method is to use the impurities in graphite to react with sodium hydroxide at high temperature, so that the impurities can be dissolved in water and hydrochloric acid to achieve the effect of purifying graphite. This method can make the carbon content of graphite reach 98 to 99.8%, which is graphite Preferred method of purification, but difficult to use for further graphite purification
The mixed acid method is a method of mixing sulfuric acid or hydrochloric acid and hydrofluoric acid in a certain proportion, soaking and purifying flake graphite under mild conditions, which can make the carbon content of graphite reach more than 99.9%, and is the main method to increase the carbon content of high-purity graphite. Chinese patents CN101654244A, CN1016347A, CN1919729A, etc. have prepared high-purity flake graphite and high-purity graphite under different processes by using the mixed acid method, so that the carbon content has reached more than 99.9%, but reaction equipment such as high-pressure reactors are used, and the process flow More complex and less secure

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Embodiment 1

[0020] Weigh high-grade pure sodium hydroxide, add high-purity water to stir and dissolve, then take high-purity flake graphite with a fixed carbon content of 99.9% by mass percentage 10% (that is, the amount of sodium hydroxide is 10wt% of the graphite amount), and add it to the hydrogen storage In a beaker of sodium oxide solution, mix and stir, melt at a temperature of 500°C for 2 hours, filter under low pressure after cooling, and wash with water 5-8 times until the pH of the filtrate is 6.5. Mix the hydrofluoric acid and hydrochloric acid solutions of the same concentration (10%) and the same volume, and add them to the polytetrafluoroethylene beaker together with the high-purity graphite after melting according to the liquid-solid ratio of 5:1, stirring at a rate of 500r / min at room temperature Under the reaction for 3 hours, the reacted material is filtered with low pressure and high-purity water for 5-8 times until the pH of the filtrate reaches 6.5;

[0021] Put the o...

Embodiment 2

[0023] Weigh high-grade pure sodium hydroxide, add high-purity water and stir to dissolve, then weigh high-purity graphite with a fixed carbon content of 99.9% according to 15% by mass, add it to a beaker containing sodium hydroxide solution, mix the slurry and stir, at a temperature of 600°C Melted for 2 hours, cooled and washed with low-pressure water for 6-8 times until the pH of the filtrate was 6.5. Mix hydrofluoric acid with a concentration of 20% and hydrochloric acid solution with a concentration of 10% in equal volumes, and add them to a polytetrafluoroethylene beaker together with the molten high-purity graphite at a liquid-solid ratio of 7:1, with a stirring rate of 500r / min at room temperature React for 3 hours, filter the reacted material with low-pressure filter, high-purity water for 6-8 times until the pH of the filtrate reaches 6.5;

[0024] Put the obtained high-purity graphite filter cake into a blast oven, dry it at 110°C, grind it, and pack it into a bag f...

Embodiment 3

[0026] Weigh high-grade pure sodium hydroxide, add high-purity water and stir to dissolve, then weigh high-purity graphite with a fixed carbon content of 99.9% according to 15% by mass, add it to a beaker containing sodium hydroxide solution, mix the slurry and stir, and heat it at a temperature of 650°C Melted for 5 hours, cooled and washed with low-pressure water for 6-8 times until the pH of the filtrate was 6.5. Mix hydrofluoric acid with a concentration of 25% and dilute hydrochloric acid with a concentration of 10% in a volume ratio of 1:3, and add them to a polytetrafluoroethylene beaker with a liquid-solid ratio of 8:1 and high-purity graphite after melting, and the stirring rate is 500r / min, react at a temperature of 40°C for 4 hours, filter the reacted material with low-pressure filtration, and continue washing with high-purity water for 7-8 times until the pH of the filtrate reaches 6.5;

[0027] Put the obtained high-purity graphite filter cake into a blast oven, ...

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Abstract

The invention discloses a method for preparing high purity graphite from graphite with higher purity, which comprises the following steps of: firstly, melting graphite with 99.9% of carbon content by using superior pure sodium hydroxide; then, treating by using superior pure mixed acid. The carbon content of the finally obtained high purity graphite reaches more than 99.98%.

Description

technical field [0001] The invention relates to the technical field of new graphite materials, in particular to a preparation method of high-purity graphite. Background technique [0002] Graphite deposits are produced in metamorphic rocks, such as gneiss, schist, etc., and associated minerals include quartz, feldspar, mica, pyrite, carbonate and other minerals. Graphite is divided into high-purity graphite, high-carbon graphite, medium-carbon graphite and low-carbon graphite according to the fixed carbon content. Graphite raw ore is generally firstly purified by flotation, and the fixed carbon content of graphite is increased to 90%-98% through multiple grinding, multiple separations, and rapid flotation, and then the graphite is purified by chemical methods or high-temperature graphitization. [0003] The high-temperature method is to make the ash in the graphite gasify and overflow at a high temperature above 2700°C under the condition of isolating the air, so as to puri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04
Inventor 刘建远申士富刘海营
Owner BEIJING GENERAL RES INST OF MINING & METALLURGY
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