A pretreatment method for the determination of graphite chemical composition content

Abstract

The invention discloses an early pre-treatment method for measuring content of chemical components in graphite. The method comprises the steps: (1), weighing 0.1-0.5 g of a graphite sample in a digestion tank, adding slowly 2-3 mL of nitric acid, 0.2-1.0 mL of hydrofluoric acid, 0.5-1 mL of sulfuric acid, and 0.2-1.0 mL of perchloric acid, and mixing well the graphite sample with acid reagents; (2), placing the digestion tank on a microwave digestion system, starting to heat under the power of 600W, holding the temperature raised to 240-260 DEG C for not shorter than 45 min, stopping the microwave digestion system, naturally cooling, removing the digestion tank from the microwave digestion system when the temperature drops to below 70 DEG C, slowly opening the digestion tank, pouring to a polytetrafluoroethylene flask, and metering the volume with a 100 mL plastic colorimetric tube. By using the method, it is possible to disintegrate the graphite sample at a temperature lower than 300 DEG C without element loss, and the measurement of impurity content of the graphite is high in accuracy.

Description

technical field [0001] The invention belongs to a preliminary pretreatment method for determining the content of graphite chemical components. Background technique [0002] Graphite is a high-energy crystalline carbon material, widely used in metallurgy, machinery, environmental protection, chemical industry, refractory, new energy, nuclear energy, electronics, fields such as medicine, military industry and aerospace. [0003] my country's natural graphite has good geological conditions, wide distribution, rich resources and good quality. Its reserves and output rank first in the world, and it is one of my country's advantageous minerals. Elements such as silicon, aluminum, calcium, magnesium, iron, titanium, manganese, and phosphorus are impurities in graphite. Graphite produced in different places contains different contents of these elements, and the contents of these elements directly affect the beneficiation and application of graphite. Mineral dressing, application a...

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Problems solved by technology

[0004] The chemical properties of graphite are stable. Under normal temperature and pressure conditions, acid and alkali are difficult to decompose it. The sample can be decomposed completely only by high temperature alkali fusion at 1000 ℃. A large amount of carbon dioxide can cause the splash of the sample, resulting in element loss and inaccurate content analysis

At present, the chemical analysis method of graphite ore in my country is to remove all carbon by burning at a high temperature of 900 ° C to 1000 ° C, and then decompose the sample by alkali fusion or acid fusion, and then use chemical analysis to determine the elements in graphite, that is, use pre-burning Burn off the carbon and then decompose the sample by alkali melting, but trace elements such as Pb, Cd, As are volatile under high temperature burning at 900℃~1000℃, and there is still element loss, and the final analyzed content is still inaccurate; Pb, Cd, As, etc. Trace elements such as As also cause environmental pollution

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