KR102165194B1 - Method of recovering manganese in cleaning solution of graphite oxide and apparatus for recovering manganese - Google Patents

Abstract

A manganese recovery method and a manganese recovery device in a graphite oxide washing solution capable of easily recovering manganese as a valuable metal from a washing solution remaining after washing the graphite oxide are proposed. The manganese recovery method in the graphite oxide washing solution according to the present invention includes a washing step of washing the oxidized graphite with distilled water using sulfuric acid and a manganese oxidizing agent; And a manganese compound recovery step of adding a recovery solvent having a low solubility of MnSO ₄ to a washing solution from which graphite oxide is removed in the washing step.

Description

Manganese recovery method and manganese recovery device in graphite oxide cleaning solution {METHOD OF RECOVERING MANGANESE IN CLEANING SOLUTION OF GRAPHITE OXIDE AND APPARATUS FOR RECOVERING MANGANESE}

The present invention relates to a manganese recovery method and manganese recovery apparatus in a graphite oxide washing solution, and more particularly, a manganese recovery method and manganese recovery in a graphite oxide washing solution capable of easily recovering manganese, a valuable metal, from the washing solution remaining after washing the graphite oxide. It relates to the device.

Graphite has a structure in which graphene, a plate-shaped two-dimensional sheet formed in a hexagonal shape, of carbon atoms is stacked. Graphite has the advantages of excellent mechanical strength, high elasticity, and high transparency due to its excellent electrical and thermal conductivity, and energy storage materials such as secondary cells, fuel cells, super capacitors, filtration membranes, chemical detectors, transparent electrodes, etc. It can be used in a variety of applications such as.

Graphene, which is produced by oxidizing graphite and then dividing it into several layers and reducing it again, also has excellent physical properties such as high thermal conductivity, high current transfer ability, and excellent stiffness, so nanoscale electrical and electronic devices, nanosensors , Optoelectronic devices, and high-functional composites are evaluated to be applied in various fields.

Graphene can be generally prepared through a chemical vapor deposition method (CVD method), a chemical synthesis method (a graphite oxidation/reduction method), or the like. After the announcement that graphene can be produced by a mechanical peeling method known as the so-called Scotch tape method, many technologies have been researched, developed, and classified.

Among these methods, a chemical synthesis method that can produce graphene at a relatively low cost as well as mass production by the top-down method is known as the most practical and simple method.

To briefly explain the chemical synthesis method, graphite is oxidized with a strong acid to disperse and exfoliate with graphene oxide (GO), and then by reducing GO through heat treatment again, reduced graphene oxide (rGO) ). That is, graphene oxide corresponds to the raw material of graphene, and is a key starting material in the graphene-based industry.

However, in the traditional method (Hummer's method) for producing graphene oxide using the above-described chemical synthesis method, the interlayer distance of graphite is very narrow (0.34nm), so it takes a long time (approximately) to induce the interlayer chemical reaction. It takes 2-5 days), making it difficult to manufacture competitive graphene oxide.

In addition, in order to shorten the manufacturing time, a method of adjusting the reaction rate through strong acid and temperature control, etc., has been proposed, but in this case, there is a problem in that the environmental problem due to the increase in the waste acid solution and the cost for treating them increase.

Potassium permanganate, which is used as an oxidizing agent, has a high temperature and risk of explosion due to runaway reaction with sulfuric acid, and a potassium and manganese washing process is required for producing high-quality graphite oxide after the reaction, and wastewater treatment generated at this time is also a problem. have.

In particular, in the case of manganese, which is a valuable metal, when it is included in sewage and disposed of as it is, there is a problem of an increase in cost as well as an environmental problem.

In embodiments of the present invention, a manganese recovery method and a manganese recovery apparatus in a graphite oxide washing solution capable of easily recovering manganese as a valuable metal from a washing solution remaining after washing the graphite oxide are provided.

A method for recovering manganese in a graphite oxide washing solution according to an aspect of the present invention includes a washing step of washing the oxidized graphite with distilled water using sulfuric acid and a manganese oxidizing agent; And a manganese compound recovery step of adding a recovery solvent having a low solubility of MnSO ₄ to a washing solution from which graphite oxide is removed in the washing step.

The washing step may be a step of washing graphite with distilled water and sulfuric acid.

The manganese oxidizing agent may be potassium permanganate.

The recovery solvent may be ethanol.

It may further include a manganese acquisition step of obtaining manganese by electrolyzing MnSO ₄ obtained in the manganese compound recovery step.

Graphite can be oxidized using hydrogen peroxide, sulfuric acid and manganese oxidizing agents.

The washing liquid may include H ⁺ , K ⁺ , HO ₂ ⁺ , SO ₄ ^2- , Mn ^{2 +} , MnO ₄ ^- and OH ^- .

According to another aspect of the present invention, a graphite oxide washing unit for washing the graphite oxide oxidized using sulfuric acid and a manganese oxidizing agent; And a manganese compound recovery unit for recovering manganese by adding a recovery solvent having a low solubility of MnSO ₄ to the cleaning solution from which the washed graphite oxide has been removed.

In the manganese recovery method in the graphite oxide washing solution according to the present invention, the acid solution or the oxidizing agent used in the process of oxidizing to obtain graphite oxide or graphene oxide from graphite remains as impurities in the graphite oxide. It has the effect of recovering and recycling manganese, a heavy metal, which is a pollutant.

In addition, since the recovery process is simple and efficient manganese recovery is possible while using a low-cost recovery solvent, it is possible to reduce raw materials, reduce manufacturing costs, and perform eco-friendly processes.

1 is a view showing a manganese recovery apparatus in a graphite oxide cleaning solution according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more completely describe the present invention to those of ordinary skill in the art. In the accompanying drawings, there may be elements having a specific pattern or having a predetermined thickness, but this is for convenience of description or distinction, so even if they have a specific pattern and a predetermined thickness, the present invention is characterized by the illustrated elements. It is not limited to only.

1 is a view showing a manganese recovery apparatus in a graphite oxide cleaning solution according to an embodiment of the present invention. The manganese recovery apparatus 100 in the graphite oxide washing liquid according to the present invention comprises: a graphite oxide washing unit 110 for washing oxidized graphite oxide using sulfuric acid and a manganese oxidizing agent; And a manganese compound recovery unit 120 for recovering manganese by adding a recovery solvent having a low solubility of MnSO ₄ to the washing solution from which the washed graphite oxide has been removed.

When the manganese recovery device 100 in the graphite oxide washing liquid is used, a washing step of washing the oxidized graphite with distilled water using sulfuric acid and manganese oxidizer performed in the graphite oxide washing unit 110; And the manganese compound recovery unit 120, a manganese compound recovery step of adding the solubility of MnSO ₄ low recovery solvent in the oxidized graphite is removed, cleaning solution in the cleaning steps performed in; MnSO ₄ form the manganese contained in the graphite wash liquid oxidation via Can be recovered with.

In the graphite oxide washing unit 110, the oxidized graphite oxide is washed using sulfuric acid and manganese oxidizing agent to obtain the washed graphite oxide. In the manganese recovery apparatus 100 in the graphite oxide washing liquid according to the present invention, graphite oxide, in which graphite is oxidized, is injected into the graphite oxide inlet 111 in the graphite oxide washing unit 110. Graphite oxide is oxidized using strong acids and oxidizing agents. Since strong acids and oxidizing agents are used, graphite oxide contains waste oxidizing agents and waste acid solutions as impurities.

The graphite before oxidation may be a commercial graphite, for example, a commercial graphite powder.

The manganese oxidizing agent may be any material capable of oxidizing graphite, and for example, potassium permanganate (KMnO ₄ ) may be used.

An acid solution that can be used for the oxidation of graphite oxide is required to oxidize graphite together with an oxidizing agent, and sulfuric acid (H ₂ SO ₄ ) is exemplified. In addition to sulfuric acid, a material selected from nitric acid, hydrochloric acid, phosphoric acid, and salts thereof (eg, sodium nitrate, NaNO ₃ ) may be additionally included. These substances function to prevent excessive reaction heat from rapidly reacting with sulfuric acid, which is a strong acid, and an oxidizing agent. The addition ratio of sulfuric acid and nitric acid may be from 2:1 to 10:1. Specifically, graphite is supported in an acid solution at room temperature and stirred, and then an oxidizing agent is added to the graphite-supported solution. The solution into which the oxidizing agent is added causes an oxidation reaction in the reactor, and as a result, graphite oxide may be produced. At this time, an additive such as hydrogen peroxide (H ₂ O ₂ ) may be added.

When sulfuric acid and a manganese oxidizing agent, especially potassium permanganate, are used during the oxidation of graphite, the graphite oxide may include sulfuric acid and potassium permanganate. Graphite oxide containing such impurities may be washed with distilled water and sulfuric acid. At this time, since graphite oxide can be obtained in the form of a very high density cake, a large amount of distilled water and sulfuric acid can be used.

That is, when distilled water and sulfuric acid are introduced into the washed graphite oxide inlet 121, the graphite oxide is washed, and the washing waste solution is introduced into the manganese compound recovery unit 120 through the washing liquid outlet 113 from which the graphite oxide has been removed.

Washing waste liquid, the ions of _{^{H +, K +, HO 2}} +, SO 4 2-, Mn 2 +, MnO 4 from sulfuric acid and potassium permanganate and ^hydrogen peroxide may be included ^- and OH. That is, the manganese compound recovery unit 120 may include H ⁺ , K ⁺ , HO ₂ ⁺ , SO ₄ ^2- , Mn ^{2 +} , MnO ₄ ^- and OH ^- . Therefore, in order to recover manganese, it is necessary to add a recovery solvent that reacts with these ions to extract manganese.

In the case of Mn ^{2 +} ions, when Na ₂ CO ₃ is added, manganese may be obtained in the form of MnCO ₃ , but since sulfuric acid or other acids are used in excess, hydrogen ions are included in the washing solution in excess and CO ₃ ^2- Is not extracted with MnCO ₃ and carbon dioxide gas is likely to be generated.

In addition, MnO ₄ ^- In the case of ions, adding an ethanol, and the following reaction to be precipitated in the form of MnO _2.

[Scheme 1]

_{C 2 H 5 OH + MnO 4} - -> CH 3 COOH + MnO 2 + H 2 O

In addition, when ethanol is added in the case of Mn ^{2 +} ions, ethanol does not directly participate in the reaction, but manganese compounds are precipitated in the form of MnSO ₄ due to the low solubility of MnSO ₄ in ethanol. That is, in the manganese compound recovery unit 120, when a recovery solvent having low solubility of MnSO ₄ is added to the recovery solvent inlet 122, a compound containing manganese can be recovered through the manganese compound outlet 123.

The MnSO ₄ obtained in the manganese compound recovery step can be electrolyzed to obtain Mn in the form of a metal.

In the above, embodiments of the present invention have been described, but those of ordinary skill in the art will add, change, delete or add components within the scope not departing from the spirit of the present invention described in the claims. Various modifications and changes can be made to the present invention by means of the like, and this will also be said to be included within the scope of the present invention.

Manganese recovery device in 100 graphite oxide cleaning solution
110 Graphite oxide cleaning unit
111 Graphite oxide inlet
112 Washing liquid inlet
113 Cleaning fluid outlet from which graphite oxide has been removed
114 Connection
120 Manganese compound recovery unit
121 Washed graphite oxide inlet
122 Recovery solvent inlet
123 Manganese compound outlet

Claims (8)

A washing step of washing the oxidized graphite with a washing solution using hydrogen peroxide, sulfuric acid and manganese oxidizer; And
A manganese compound recovery step of adding a recovery solvent having a low solubility of MnSO ₄ to a washing solution from which graphite oxide is removed in the washing step, wherein the method for recovering manganese in a graphite oxide washing solution comprising:
The washing liquid is distilled water and sulfuric acid,
The manganese oxidizing agent is potassium permanganate,
The recovery solvent is ethanol,
The washing solution includes H ⁺ , K ⁺ , H0 ₂ ⁺ , SO ₄ ^2- , Mn ²⁺ , MnO ₄ ^- and OH ^- ,
MnO ₄ ^- was recovered by adding ethanol,
Manganese recovery method in a graphite oxide washing solution, characterized in that the Mn ²⁺ is recovered by adding Na ₂ CO ₃ . delete delete delete The method according to claim 1,
Manganese acquisition step of obtaining manganese by electrolyzing MnSO ₄ obtained in the manganese compound recovery step; manganese recovery method in a graphite oxide washing solution further comprising. delete delete A graphite oxide washing unit in which the graphite oxide oxidized using hydrogen peroxide, sulfuric acid, and manganese oxidizer is washed with a washing solution; And
A manganese compound recovery unit for recovering manganese by adding a recovery solvent having a low solubility of MnSO ₄ to the washing solution from which the washed graphite oxide is removed, comprising: a manganese compound recovery unit in the graphite oxide washing solution,
The washing liquid is distilled water and sulfuric acid,
The manganese oxidizing agent is potassium permanganate,
The recovery solvent is ethanol,
The washing solution includes H ⁺ , K ⁺ , H0 ₂ ⁺ , SO ₄ ^2- , Mn ²⁺ , MnO ₄ ^- and OH ^- ,
MnO ₄ ^- was recovered by adding ethanol,
Manganese recovery device in graphite oxide washing liquid, characterized in that the Mn ²⁺ is recovered by adding Na ₂ CO ₃ .

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