阅读说明：本技术 一种天然微晶石墨的提纯方法 (A kind of method of purification of natural micro crystal graphite ) 是由 毋伟 席国强 王武 郭丙炎 于 2019-09-09 设计创作，主要内容包括：一种天然微晶石墨的提纯方法,属于石墨提纯技术领域。该方法包括以下步骤：步骤1,以天然微晶石墨为原料,与摩尔浓度为1M～8M的NaOH溶液混合后在2～16V的交替电流下充分搅拌反应,交替频率为0.01～0.1Hz,然后将溶液与石墨分离、洗涤、烘干得到碱洗石墨；步骤2,以碱洗石墨为原料,将碱洗石墨与1～10M的H<Sub>2</Sub>SO<Sub>4</Sub>一起加入水热釜中,在高温加压下浸渍反应,反应结束后将溶液与石墨离心、抽滤得到酸洗石墨；步骤3,将酸洗石墨在高温下烘干,并去除挥发分,得到碳含量在99％以上的微晶石墨。该方法反应条件温和,能耗低,环境污染小,废液易处理、不破坏石墨结构,而且提纯效率高。(A kind of method of purification of natural micro crystal graphite, belongs to technical field of graphite purification.Method includes the following steps: step 1, using natural micro crystal graphite as raw material, it is reacted with being sufficiently stirred under the alternative current of 2~16V after the NaOH solution mixing that molar concentration is 1M~8M, alternating frequency is 0.01~0.1Hz, then separates solution with graphite, washs, drying and obtain alkali cleaning graphite；Step 2, using alkali cleaning graphite as raw material, by the H of alkali cleaning graphite and 1~10M 2 SO 4 It is added in water heating kettle together, the impregnation under high-temperature pressurizing, solution and graphite centrifugation, suction filtration is obtained into pickling graphite after reaction；Step 3, pickling graphite is dried at high temperature, and removes volatile matter, obtain micro crystal graphite of the carbon content 99% or more.This method reaction condition is mild, and low energy consumption, and environmental pollution is small, and waste liquid is easy to handle, does not destroy graphite-structure, and purification efficiency is high.)

1. a kind of method of purification of natural micro crystal graphite, which comprises the following steps:

Step 1, it using natural micro crystal graphite as raw material, reacts under alternative current with after NaOH solution mixing, is sufficiently stirred simultaneously Solution and graphite are centrifugated after reaction, wash, filter and obtain alkali cleaning graphite after drying by reaction solution；

Step 2, by alkali cleaning graphite and H₂SO₄It is added in water heating kettle after solution mixing, impregnation under high temperature, after reaction Solution and graphite are centrifugated, obtain pickling graphite after washing, filtering；

Step 3, volatile matter is being dried and removed to pickling graphite, the micro crystal graphite purified.

2. a kind of method of purification of natural micro crystal graphite described in accordance with the claim 1, which is characterized in that natural micro crystal graphite is pure Degree is 80%~90%, and partial size is 1~10 μm.

3. a kind of method of purification of natural micro crystal graphite described in accordance with the claim 1, which is characterized in that micro crystal graphite is in NaOH Mass concentration in solution is 0.2~0.4g/ml, and the molar concentration of NaOH solution is 1~8M.

4. a kind of method of purification of natural micro crystal graphite described in accordance with the claim 1, which is characterized in that applied in step 1 Alternately the voltage of DC current is 2~16V, and alternating frequency is 0.01~0.1Hz.

5. a kind of method of purification of natural micro crystal graphite described in accordance with the claim 1, which is characterized in that be powered item in step 1 2~10h is stirred to react under part, reaction temperature is room temperature.

6. a kind of method of purification of natural micro crystal graphite described in accordance with the claim 1, which is characterized in that alkali cleaning micro crystal graphite exists H₂SO₄Mass concentration in solution are as follows: 0.2~0.5g/ml, H₂SO₄Molar concentration be 1~10M.

7. a kind of method of purification of natural micro crystal graphite described in accordance with the claim 1, which is characterized in that step 2 high temperature water The time of hot submersion reaction is 2~16h, and reaction temperature is 100~180 DEG C.

8. a kind of method of purification of natural micro crystal graphite described in accordance with the claim 1, which is characterized in that be first centrifuged in step 3 Pickling graphite is separated with solution, suction filtration is then washed with water to cleaning solution pH value 6~7, gained filter cake is dried and removed Volatile matter obtains the micro crystal graphite of high-purity.

Technical field

The present invention relates to a kind of methods of purification of natural graphite, and natural micro crystal graphite especially lesser to partial size mentions The method that pure and mild condition, environmental pollution are small, purification efficiency is high.

Background technique

Graphite is a kind of high energy crystal carbon material, because of its unique structure and high temperature resistant, thermally conductive, lubrication, thermal shock resistance, change Learn the superperformances such as stability is good, be widely used in metallurgy, machinery, chemical industry, fire resisting, new energy, electronics, medicine, military project and The fields such as aerospace.

There is a large amount of natural graphite mineral, including crystalline flake graphite and micro crystal graphite (MG) on earth.The latter usually has < 1 μm of small crystalline size and carbon content is higher.China is the existing explored maximum micro crystal graphite storage site in Asia or even the world, lake The largest domestic mine reserve in southern province Chenzhou City reed pool area is more than 30,000,000 tons.In addition, the Inner Mongol (Bayan nguktrum), Hubei Also there are other main mineral deposits in (Shiyan), Fujian (Sanming City), the provinces such as Jilin (huge rock) and Heilungkiang (Yichuan).Some Mineral Deposits of Europe Grade is about 55%, and the grade in China Partial micro crystal graphite mineral deposit is 50%-85%.

There are two Main Trends of The Development for natural microcrystalline graphite product in modern industry, and one is high-purity, the other is super Fine grained.But micro crystal graphite crystal grain is tiny, partial impurities (quartz, silicate mineral, aluminium oxide, magnesium, calcium and other non-graphite groups Point) be wrapped in inside crystal grain aggregate and be difficult to separate, lead to purify that difficulty is big, this is to restrict micro crystal graphite in high-technology field Using and development an important factor for one of.

Micro crystal graphite purifying method common at present includes floatation, hydrogen fluoride, hydrofluoric acid-hydrochloric acid (sulfuric acid) nitration mixture Method, high temperature method, chlorinating roasting, alkali acid system etc..But these methods suffer from respective disadvantage in terms of industrial application.

He Guoshuai etc. (He Guoshuai, Hunan Lu Tang cryptocrystalline graphite mine Experimental study on ore dressing, mineral products protection and utilization, 2018,5, 57-61) selecting kerosene is collecting agent, and sodium carbonate is dispersing agent, using sec-octyl alcohol as foaming agent, is consolidated micro crystal graphite using floatation Determine carbon content and is promoted to 87.26% from 70.28%.(Jiang Fang, hydrochloric acid-hydrofluoric acid purifying prepare micro crystal graphite research, carbon to Jiang Fang etc. Plain technology, 2014,5,23-25) using HC1-HF mixed acid process purification micro crystal graphite, have studied the concentration and reaction of HC1 and HF Fixed carbon content is increased to 99.36% by influence of the time to refining effect.But since hydrofluoric acid toxicity is big, corrosivity is strong, right Human body and environmental hazard are larger, this constrains the application of this method significantly.Wen Zhonghua (application number: 201310128084.2) etc. logical Design high temperature method continuous industrial graphite purification furnace body is crossed, high-purity micro crystal graphite of purity 99.99% is obtained.But the method exists The disadvantages of equipment is expensive, and energy consumption is high, working condition harshness and small yield, is only applicable to produce ultra-pure graphite.Chlorinating roasting Refining effect is good, at low cost, but the toxicity of chlorine and corrosivity can generate grave danger to human body and ecological environment, in addition, chlorine The process system for changing roasting method is unstable, and the grade of graphite concentrate fluctuates the factors such as larger and also affects the method to a certain extent Practical application.

It is to be mixed in a certain ratio graphite and NaOH solid that alkali acid system, which purifies graphite, is put into stove and is calcined, In NaOH is reacted under high temperature with molten condition and the metal oxide in graphite, mainly generates sodium metaaluminate or silicates Object is closed, its molten filters in water is removed, remaining unreacted metal oxide dissolves in acid condition, further increases production The purity of object.Although above-mentioned alkali acid system refining effect is good, wastewater treatment is relatively easy, and energy consumption is high, complex process, the reaction time It is long, and equipment seriously corroded, the micro crystal graphite grade after furthermore purifying still are difficult to reach the requirement of high purity graphite.(the ginger such as Jiang Fang Virtue, alkali acid system purify certain micro crystal graphite metal mine, 2014,32 (9): 82-84) tradition is used to Certain District, Hunan micro crystal graphite Alkali acid system is purified, by fixed carbon content be 85% graphite purification to 98.79%.

Summary of the invention

The purpose of the present invention is for existing alkali acid system purify natural micro crystal graphite there are the shortcomings that, on this basis into Row improves, and provides a kind of mild condition, environmental-friendly and high purification efficiency natural micro crystal graphite purifying method.

The technical scheme of the present invention is realized as follows:

A kind of method of purification of natural micro crystal graphite, which comprises the following steps:

Step 1, it using natural micro crystal graphite as raw material, is reacted under alternative current with after NaOH solution mixing, while sufficiently It is stirred to react solution, solution and graphite are centrifugated after reaction, washes, filter and obtain alkali cleaning graphite after drying；

Step 2, by alkali cleaning graphite and H₂SO₄It is added in water heating kettle after solution mixing, impregnation under high temperature, reaction knot Solution and graphite are centrifugated after beam, obtain pickling graphite after washing, filtering.

Step 3, volatile matter is being dried and removed to pickling graphite, the micro crystal graphite purified.

It is preferred that natural micro crystal graphite purity is 80%~90%, partial size is 1~10 μm.

It is preferred that mass concentration of the micro crystal graphite in NaOH solution is 0.2~0.4g/ml, the molar concentration of NaOH solution is 1~8M.

The voltage for replacing DC current applied in preferred steps 1 is 2~16V, and alternating frequency is 0.01~0.1Hz.

2~10h is stirred to react in preferred steps 1 under power on condition, reaction temperature is room temperature.

It is preferred that alkali cleaning micro crystal graphite is in H₂SO₄Mass concentration in solution are as follows: 0.2~0.5g/ml, H₂SO₄Molar concentration For 1~10M.

The time of 2 high temperature hydro-thermal impregnation of preferred steps is 2~16h, and reaction temperature is 100~180 DEG C.

It is first centrifuged in preferred steps 3 and separates pickling graphite with solution, suction filtration is then washed with water to cleaning solution pH value 6 ~7, volatile matter is dried and removed to gained filter cake, obtains the micro crystal graphite of high-purity.

Using method of purification of the invention, micro crystal graphite can be fixed carbon content from 80%~90% improve to 99% with On, and lost substantially without graphite in the process.Compared with the alkali acid system being widely used at present, by the present invention in that at electrochemistry Reason not only greatly reduces energy consumption, moreover it is possible to avoid the oxidation and matter of graphite at high temperature instead of the high-temperature fusion process of NaOH Amount loss.The advantages that this method has mild condition, and low energy consumption, environmental-friendly, and waste liquid is easy to handle.

Detailed description of the invention

Fig. 1 micro crystal graphite purification schemes schematic diagram；

1 micro crystal graphite of Fig. 2 embodiment purification front and back XRD analysis.

Specific embodiment

In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention, The technical solution of the embodiment of the present invention is clearly and completely described.Obviously, described embodiment is of the invention one Point embodiment, rather than limiting the scope of the present invention.

The mode for applying alternative current is that two electrode bars or two opposite electrode plates, electrode are put into reaction solution Stick or electrode plate are separately connected alternate DC voltage.