阅读说明：本技术 一种同时制备高纯氢氧化镁和高纯石墨烯的方法 (Method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene ) 是由 邓信忠 陈红 梁海 王晓民 杨云洪 郭丽莉 薛志爽 于 2021-01-12 设计创作，主要内容包括：一种同时制备高纯氢氧化镁和高纯石墨烯的方法,包括如下步骤：(1)配置电解溶液A和电解溶液B；(2)用相应的电极材料和隔膜组装直流电解装置；(3)通直流电进行恒电压电解；(4)超声分散阳极产品；(5)分别静置分层获得沉淀A和沉淀B；(6)冷冻干燥沉淀A,获得产品高纯石墨烯；烘箱干燥沉淀B,获得产品高纯氢氧化镁。本发明提出的一种同时制备高纯氢氧化镁和高纯石墨烯的方法,解决了在同一个装置内同时生产出高纯氢氧化镁和高纯石墨烯的问题,提高生产过程的电能利用率,降低了生产成本,并且工艺简单、装置容易加工,适合于工业化大规模生产。(A method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene comprises the following steps: (1) preparing an electrolytic solution A and an electrolytic solution B; (2) assembling a direct current electrolysis device by using corresponding electrode materials and a diaphragm; (3) d, electrifying direct current to carry out constant voltage electrolysis; (4) ultrasonically dispersing an anode product; (5) standing and layering respectively to obtain a precipitate A and a precipitate B; (6) freeze-drying the precipitate A to obtain the high-purity graphene product; drying the precipitate B in an oven to obtain the high-purity magnesium hydroxide product. The method for simultaneously preparing the high-purity magnesium hydroxide and the high-purity graphene solves the problem of simultaneously producing the high-purity magnesium hydroxide and the high-purity graphene in the same device, improves the electric energy utilization rate in the production process, reduces the production cost, has simple process and easy processing of the device, and is suitable for industrial large-scale production.)

1. A method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene is characterized by comprising the following steps:

preparing a magnesium salt solution A and a magnesium salt solution B: preparing a magnesium salt A solution with the concentration of 10-40% by using deionized water, and preparing a magnesium salt B solution with the concentration of 1-50% by using deionized water;

assembling a direct current electrolysis device: graphite is used as an anode, and a metal plate is used as a cathode; the two electrode plates are respectively connected with the positive electrode and the negative electrode of the direct current power supply through leads; a diaphragm is arranged between the anode plate and the cathode plate and divides the electrolytic cell into an anode chamber and a cathode chamber;

and D, electrifying direct current for electrolysis: adding the prepared magnesium salt A solution into the anode chamber, adding the prepared magnesium salt B solution into the cathode chamber, switching on a direct current power supply, and controlling the current density between the two polar plates to be 0.1-4A/cm²Carrying out constant voltage electrolysis;

ultrasonic dispersion: performing ultrasonic dispersion on the product obtained by the anode, wherein the ultrasonic power is 10-100 kHz, and the dispersion time is 5-60 min;

standing and layering: standing the ultrasonically dispersed anode product and a product obtained by cathode electrodeposition for 1-30 min respectively, and performing vacuum filtration to obtain a supernatant and a precipitate A, and a supernatant and a precipitate B respectively;

and (3) drying: drying the precipitate A for 60-360 min from-40-120 ℃ by a freeze dryer through programmed heating to obtain a product graphene; and drying the precipitate B for 60-360 min at 80-120 ℃ through an oven to obtain the product magnesium hydroxide.

2. The method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene according to claim 1, wherein in the step (1), the magnesium salt A is magnesium sulfate, magnesium manganate, magnesium chlorate or a mixture of the magnesium sulfate, the magnesium manganate and the magnesium chlorate.

3. The method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene according to claim 1, wherein in the step (1), the magnesium salt B is selected from magnesium chloride, magnesium sulfate, magnesium nitrate or a mixture of the magnesium chloride, the magnesium sulfate and the magnesium nitrate.

4. The method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene according to claim 1, wherein in the step (2), the graphite anode is selected from highly oriented pyrolytic graphite, flake graphite or cryptocrystalline graphite.

5. The method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene according to claim 1, wherein in the step (2), the metal plate cathode is selected from a metal copper plate, a metal titanium plate or a metal titanium plate with an oxidation coating.

6. The method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene according to claim 1, wherein in the step (2), the diaphragm is made of polypropylene film, cation exchange film or polytetrafluoroethylene film.

7. The method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene according to claim 1, wherein in the step (3), electrochemical intercalation is performed in an anode chamber to prepare graphene, and electrochemical deposition is performed in a cathode chamber to prepare magnesium hydroxide.

8. The method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene according to claim 1, wherein in the step (3), the electrolysis time is 1-12 hours after electrification or the anode plate finishes the reaction.

9. The method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene according to claim 1, wherein in the step (3), the direct current electrolysis temperature is room temperature electrolysis.

10. The method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene according to claim 1, wherein in the step (6), the temperature programming rate is 1-10 ℃/min.

Technical Field

The invention belongs to the technical field of materials, and particularly relates to a method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene.

Background

High-Purity Magnesium Hydroxide (High Purity Magnesium Hydroxide) with content of more than 99 percent and chemical molecular formula of Mg (OH)₂White solid, crystalline or amorphous powder, insoluble in water, insoluble in alkaline solutions, soluble in dilute acid and ammonium salt solutions, is decomposed into magnesium oxide and water by heating, the initial decomposition temperature is 340 ℃, the decomposition speed is fastest at 430 ℃, and the decomposition is complete at 490 ℃. The product is safe, nontoxic and harmless to the environment, and is not a flammable and explosive product. The high-purity magnesium hydroxide can be used as a terminal product to be directly used in the industries of flame retardance, electronics, medicines, foods and the like, wherein the most demanded quantity is the flame retardance industry, and is a preferred high-quality raw material for producing high-purity high-end magnesium oxide products such as high-purity light magnesium oxide, high-purity heavy magnesium oxide, medical grade magnesium oxide, electrical grade magnesium oxide, silicon steel grade magnesium oxide and the like. However, the yield of high-purity magnesium hydroxide in China is insufficient, a large amount of imported high-purity magnesium hydroxide is required every year, and the trend of increasing year by year is presented.

High-Purity Graphene (High Purity Graphene) is widely applied to battery electrode materials, semiconductor devices, transparent display screens, sensors, capacitors, transistors and the like. The research and application development of graphene continuously raises the temperature, and the excellent performance and potential application value of graphene materials have made a series of important progresses in a plurality of subject fields such as chemistry, materials, physics, biology, environment, energy and the like. Researchers are working on trying different methods in different fields in order to prepare high quality, large area graphene materials. However, the preparation of high-purity graphene is still in an early stage, and the quality of some graphene is not enough to embody various 'ideal' properties of graphene.

Based on the problems, the invention provides a method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene. The method can produce high-purity magnesium hydroxide and high-purity graphene simultaneously in the same device, has simple process and easy processing of the device, and is suitable for industrial large-scale production.

Disclosure of Invention

A method for simultaneously preparing high-purity magnesium hydroxide and high-purity graphene is characterized by comprising the following steps:

(1) preparing a magnesium salt solution A and a magnesium salt solution B: preparing a magnesium salt A solution with the concentration of 10-40% by using deionized water, and preparing a magnesium salt B solution with the concentration of 1-50% by using deionized water;

(2) assembling a direct current electrolysis device: graphite is used as an anode, and a metal plate is used as a cathode; the two electrode plates are respectively connected with the positive electrode and the negative electrode of the direct current power supply through leads; a diaphragm is arranged between the anode plate and the cathode plate and divides the electrolytic cell into an anode chamber and a cathode chamber;

(3) and D, electrifying direct current for electrolysis: adding the prepared magnesium salt A solution into the anode chamber, adding the prepared magnesium salt B solution into the cathode chamber, switching on a direct current power supply, and controlling the current density between the two polar plates to be 0.1-4A/cm 2 to carry out constant voltage electrolysis;

(4) ultrasonic dispersion: performing ultrasonic dispersion on the product obtained by the anode, wherein the ultrasonic power is 10-100 kHz, and the dispersion time is 5-60 min;

(5) standing and layering: standing the ultrasonically dispersed anode product and a product obtained by cathode electrodeposition for 1-30 min respectively, and performing vacuum filtration to obtain a supernatant and a precipitate A, and a supernatant and a precipitate B respectively;

(6) and (3) drying: drying the precipitate A for 60-360 min from-40-120 ℃ by a freeze dryer through programmed heating to obtain a product graphene; and drying the precipitate B for 60-360 min at 80-120 ℃ through an oven to obtain the product magnesium hydroxide.

The magnesium salt A is magnesium sulfate, magnesium manganate, magnesium chlorate or a mixture of the magnesium sulfate, the magnesium manganate and the magnesium chlorate.

The magnesium salt B is selected from magnesium chloride, magnesium sulfate, magnesium nitrate or a mixture of the magnesium chloride, the magnesium sulfate and the magnesium nitrate.

The graphite anode is block graphite, crystalline flake graphite or aphanitic graphite.

The metal plate cathode is a metal copper plate, a metal titanium plate or a metal titanium plate with an oxidation coating.

The diaphragm material is selected from a polypropylene membrane, a cation exchange membrane or a polytetrafluoroethylene membrane.

And carrying out electrochemical intercalation in the anode chamber to prepare graphene, and carrying out electrochemical deposition in the cathode chamber to prepare magnesium hydroxide.

The electrolysis time is 1-12 hours after electrification or the anode plate finishes the electrolysis after reaction.

The direct current electrolysis temperature is room temperature electrolysis.

The temperature programming rate is 1-10 ℃/min.

Drawings

FIG. 1 is a schematic flow diagram of the process of the present invention;

FIG. 2 is an X-ray diffraction chart of magnesium hydroxide obtained in example 1 of the present invention;

fig. 3 is an X-ray diffraction pattern of graphene obtained in example 2 of the present invention.

The invention has the advantages of

The method for simultaneously preparing the high-purity magnesium hydroxide and the high-purity graphene solves the problem of simultaneously producing the high-purity magnesium hydroxide and the high-purity graphene in the same device, improves the electric energy utilization rate in the production process, reduces the production cost, has simple process and easy processing of the device, and is suitable for industrial large-scale production.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to be limiting. The upper and lower line values and intervals of the process parameters listed in the technical scheme of the invention can realize the products required by the invention.

Example 1

(1) Preparing a magnesium sulfate solution A and a magnesium chloride solution B: preparing magnesium sulfate into a magnesium sulfate A solution with the concentration of 10% by using deionized water, and preparing magnesium chloride into a magnesium chloride B solution with the concentration of 10% by using the deionized water;

(2) assembling a direct current electrolysis device: taking highly oriented pyrolytic graphite as an anode and a metal titanium plate as a cathode; the two electrode plates are respectively connected with the positive electrode and the negative electrode of the direct current power supply through leads; a polytetrafluoroethylene diaphragm is arranged between the anode plate and the cathode plate and divides the electrolytic cell into an anode chamber and a cathode chamber;

(3) and D, electrifying direct current for electrolysis: adding the prepared magnesium sulfate A solution into the anode chamber, adding the prepared magnesium chloride B solution into the cathode chamber, switching on a direct current power supply, and controlling the current density between the two polar plates to be 0.5A/cm2 to carry out constant voltage electrolysis;

(4) ultrasonic dispersion: performing ultrasonic dispersion on the product obtained by the anode, wherein the ultrasonic power is 50kHz, and the dispersion time is 30 min;

(5) standing and layering: standing the ultrasonically dispersed anode product and the product obtained by cathode electrodeposition for 30min, and respectively obtaining supernatant and precipitate A, supernatant and precipitate B by vacuum filtration;

(6) and (3) drying: drying the precipitate A for 240min from-40 to 100 ℃ by a freeze dryer through programmed heating, wherein the heating rate is 5 ℃/min, and obtaining a product graphene; and drying the precipitate B for 120min at 100 ℃ by an oven to obtain the product magnesium hydroxide.

Example 2

(1) Preparing a magnesium sulfate solution A and a magnesium sulfate solution B: preparing magnesium sulfate into a 20% magnesium sulfate A solution by using deionized water, and preparing magnesium chloride into a 20% magnesium sulfate B solution by using the deionized water;

(2) assembling a direct current electrolysis device: taking the flake graphite as an anode and a metal titanium plate with an oxidation coating as a cathode; the two electrode plates are respectively connected with the positive electrode and the negative electrode of the direct current power supply through leads; a cation exchange diaphragm is arranged between the anode plate and the cathode plate and divides the electrolytic cell into an anode chamber and a cathode chamber;

(3) and D, electrifying direct current for electrolysis: adding the prepared magnesium sulfate A solution into the anode chamber, adding the prepared magnesium sulfate B solution into the cathode chamber, switching on a direct current power supply, and controlling the current density between the two polar plates to be 1A/cm2 to carry out constant voltage electrolysis;

(4) ultrasonic dispersion: performing ultrasonic dispersion on the product obtained by the anode, wherein the ultrasonic power is 40kHz, and the dispersion time is 30 min;

(5) standing and layering: standing the ultrasonically dispersed anode product and the product obtained by cathode electrodeposition for 30min, and respectively obtaining supernatant and precipitate A, supernatant and precipitate B by vacuum filtration;

(6) and (3) drying: drying the precipitate A for 360min from-40 to 100 ℃ by a freeze dryer through programmed heating, wherein the heating rate is 10 ℃/min, and obtaining a product graphene; and drying the precipitate B for 240min at 110 ℃ by an oven to obtain the product magnesium hydroxide.

Example 3

(1) Preparing a magnesium manganate solution A and a magnesium nitrate solution B: preparing magnesium sulfate into a magnesium manganate A solution with the concentration of 15% by using deionized water, and preparing magnesium chloride into a magnesium nitrate B solution with the concentration of 25% by using the deionized water;

(2) assembling a direct current electrolysis device: taking the flake graphite as an anode and the metal copper plate as a cathode; the two electrode plates are respectively connected with the positive electrode and the negative electrode of the direct current power supply through leads; a cation exchange diaphragm is arranged between the anode plate and the cathode plate and divides the electrolytic cell into an anode chamber and a cathode chamber;

(3) and D, electrifying direct current for electrolysis: adding the prepared magnesium manganate A solution into an anode chamber, adding the prepared magnesium nitrate B solution into a cathode chamber, switching on a direct-current power supply, and controlling the current density between the two polar plates to be 0.75A/cm2 to carry out constant-voltage electrolysis;

(4) ultrasonic dispersion: performing ultrasonic dispersion on the product obtained by the anode, wherein the ultrasonic power is 50kHz, and the dispersion time is 30 min;

(5) standing and layering: standing the ultrasonically dispersed anode product and the product obtained by cathode electrodeposition for 30min, and respectively obtaining supernatant and precipitate A, supernatant and precipitate B by vacuum filtration;

(6) and (3) drying: heating the precipitate A from-40 to 110 ℃ by a freeze dryer through a program, wherein the heating rate is 10 ℃/min, and drying for 240min to obtain a product graphene; and drying the precipitate B for 360min at 110 ℃ by an oven to obtain the product magnesium hydroxide.