Purification method of natural cryptocrystalline graphite

Abstract

The invention provides a purification method of natural cryptocrystalline graphite. The method using natural cryptocrystalline graphite as a raw material comprises the following steps: adding a sodium hydroxide solid and an assistant to the raw material, adding water, heating, fully stirring the obtained solution for a reaction, separating the solution and graphite, washing, precipitating, filtering, and drying to prepare alkali washed graphite, wherein the assistant is composed of sodium metaborate and sodium diisobutyl naphthalene sulfonate; adding alkali washed graphite, a soluble fluoride salt and nitric acid into a reaction container, heating while carrying out a stirring and soaking reaction, and separating the obtained solution and graphite to prepare graphite; and washing acid-containing graphite, precipitating, filtering, and drying to prepare graphite with the carbon content of above 99.90%. The purification method has the advantages of low energy consumption, little environmental pollution and high purification efficiency.

Description

technical field [0001] The invention relates to a method for purifying natural graphite, in particular to a method for purifying natural aphanitic graphite as a raw material with little environmental pollution and low energy consumption. Background technique [0002] Microcrystalline graphite is an important raw material and additive in many industrial productions, and is also widely regarded as industrial monosodium glutamate. There are reserves of microcrystalline graphite in some countries and regions such as Asia, America, and Europe, and my country is the largest proven microcrystalline graphite reserve in Asia and even the world, and the reserves after repeated exploration are more than 34 million tons. In recent years, with the rapid development of electronic information industry, nuclear industry, national defense industry and automobile industry, the graphite market has also undergone tremendous changes. First of all, the market demand for "quantity" has increased,...

AI Technical Summary

Problems solved by technology

Among them, the flotation method has the lowest cost, the least energy consumption and reagent consumption, but it is difficult to obtain graphite with a carbon content of more than 95%; the removal efficiency of the hydrofluoric acid method and the hydrofluoric acid-salt (sulfur) acid method is high, The energy consumption is also relatively low, but the scope of application of this method is limited due to the high toxicity and strong corrosiveness of hydrofluoric acid, which pollutes the environment

The content of graphite purified by alkali-acid method can reach more than 99%, but in the process of alkali calcination, high temperature sintering is required, energy consumption is large, equipment corrosion is serious, and purification process steps are long. Therefore, it is necessary to optimize process conditions, reduce energy loss, and minimize Reduce costs and improve efficiency

The carbon content of graphite purified by the two-step alkali-acid method is difficult to reach more than 99.90%. Even if the melting temperature is increased to 800 degrees, the carbon content can only be increased to 99.80%.