KR19990015664A - Manufacturing Method of High Purity Manganese Trioxide for Magnetic Materials - Google Patents

Abstract

The present invention is an improved manufacturing method for producing economically and efficiently high-purity trimanganese tertaoxide for manganese ferrite (Mn-Ferrites) used as a magnetic material, and the particle size of manganese powder is 50 mesh or less. The reaction product is dispersed in the solution by stirring during the reaction, and oxygen or an oxidizing gas containing oxygen is introduced into the solution through a nozzle having an inner diameter of 10 mm or less to form a small droplet for reaction, and the reaction filtrate is recycled. It relates to a high purity, fine manganese tetraoxide.

According to the present invention, manganese trioxide powder can be obtained in a short time by using a smaller amount of the reaction additive at a higher manganese metal concentration by promoting the reaction through the dispersion of the reactants using the stirring during the reaction and the improvement of the oxidizing gas input method. The manganese trioxide powder obtained in this way contains no unreacted substance and has an average particle size of 0.3 μm or less and is a fine, high purity manganese trioxide powder. In addition, in the present invention, the reaction filtrate can be recycled to complete the reaction in a short time by using a smaller amount of the reaction additive, and economically by eliminating the contamination problem caused by the discharge of the filtrate as well as reducing the amount of the reaction additive. It can manufacture.

Description

Manufacturing Method of High Purity Manganese Trioxide for Magnetic Materials

The present invention relates to an improved manufacturing method for economically and efficiently producing high purity Trimanganese Tetraoxide for manganese ferrite (Mn-Ferrites) used as a magnetic material. More specifically, in the present invention, the metal manganese powder is added to an aqueous solution together with a reaction additive selected from amino acids or water-soluble ammonium salts, and the reactants are dispersed by stirring while heating, and the metal is oxidized gas containing oxygen or oxygen. When the manganese trioxide is prepared by oxidizing the manganese powder, the metal manganese powder has a particle size of 50 mesh or less, and an oxidizing gas containing oxygen or oxygen is introduced into the solution through a nozzle having an inner diameter of 10 mm or less to form small droplets. A method for producing a high purity, fine manganese tetraoxide powder consisting of reacting and recycling a reaction filtrate.

In general, manganese trioxide powder is prepared by reduction of MnO ₂ , MnOOH or by oxidation of Mn (OH) ₂ . In the case of reduction, manganese trioxide can be obtained by reducing manganese oxide by heating a manganese oxide such as Mn ₂ O ₃ , MnO ₂ , MnOOH in a furnace with methane gas as a reducing agent. . In the case of applying this process, heat treatment is performed between 250 ° C and 550 ° C to prevent the formation of MnO due to excessive reduction. The method of obtaining manganese trioxide powder by such a process has the advantage that the process is simple, but it is difficult to produce MnO as an impurity due to excessive reduction during heat treatment, and it is difficult to manufacture with high purity, and sintering of Mn ₃ O ₄ by high temperature (Sintering) has a disadvantage in that the reactivity decreases when used as a raw material for ferrite production because the surface area decreases as the particle size of the prepared powder increases.

Another process for producing high purity manganese trioxide powder is a method of oxidizing a manganese metal powder in water in a pressurized reactor. In this case, the temperature is required to be about 100 ℃ to 140 ℃, the pressure is about 40 psi to 70 psi and the catalyst is added. In general, the reaction time is short, the powder produced has the advantages of high purity, small particle size and uniformity, but because the equipment is expensive and high temperature and high pressure is required, it is not economical due to excessive use of energy.

In addition, there is a method of producing manganese trioxide by adding an alkali such as ammonia water to an aqueous solution of manganese sulfate to form manganese hydroxide. This method has the advantage that the manufactured manganese trioxide has a small particle size, but the wastewater containing sulfuric acid ions from manganese sulfate is produced during the manufacturing process. If present, the quality of the magnetic material is degraded, so the problem of washing with water to remove it is followed.

Recently, manganese powder is dispersed in an aqueous solution with an ammonium salt selected from NH ₄ Cl, NH ₄ Br, NH ₄ I, NH ₄ NO ₃ , and (NH ₄ ) ₂ SO ₄ , and heated to contain oxygen or oxygen as an oxidant. A method of preparing manganese tetraoxide powder by introducing a gas into an aqueous solution is known. This is the anion contained in the salt ^{(Cl -, Br -, I} -, NO 3 -, (SO 4) 2 -) waste water treatment problem and an anionic the final product for handling corrosive and negative ions in the reaction vessel by There is a problem of washing with water to prevent the remaining of manganese trioxide. And during the reaction, while a sudden reaction occurs on the surface of the metal manganese powder, the metal manganese powder is agglomerated in a lump state, there is a problem that the agglomeration of the agglomerated metal manganese powder is not sufficiently oxidized and the purity falls.

In addition, the metal manganese powder is dispersed in an aqueous solution by using an amino acid or an ammonium salt as a reaction additive, and it is heated and stirred to inject a gas containing oxygen or oxygen into the aqueous solution to oxidize the metal manganese trioxide to Laboratory methods of preparation have been reported.

In this method, metal manganese powders of at least 140 mesh were used at a concentration of 125g / L and the additives were added at a concentration of 0.13 mol / L to react. Particularly, all experiments were conducted using 40 ml of aqueous solution, and it was reported that ammonium acetate could be used with 2 L aqueous solution. In this case, the formation of manganese trioxide in the amount of 40ml of aqueous solution is difficult to say that it is applied even in the industrial production of a large amount of manganese trioxide, and also an important oxidant gas in obtaining high purity manganese trioxide without any unreacted substances. It is difficult to use this method directly industrially because it does not specify the type, amount and amount of agitation. According to the above literature, the size and purity of the powder obtained by only reporting spherical powder having a specific surface area of 5 to 40 m ² / g in the characteristics of the produced manganese trioxide powder are not known.

In the present invention was studied to solve the above problems, by adjusting the particle size of the metal manganese powder, dispersing the reactants during the reaction through agitation, improving the method of adding the oxidizing gas, recycling the reaction filtrate, namely the most economic conditions The present invention has been accomplished by producing high purity, fine manganese tetraoxide powders at high metal manganese concentrations, small amounts of reaction additives, and shorter reaction times.

An object of the present invention is to disperse a metal manganese powder by oxidizing the metal manganese powder with an oxidizing gas containing oxygen or oxygen while dispersing the metal manganese powder in an aqueous solution with a reaction additive selected from amino acids or water-soluble ammonium salts and performing heating and stirring. In the manufacturing method, the metal manganese powder has a particle size of 50 mesh or less, an oxidizing gas containing oxygen or oxygen is introduced through a nozzle having an inner diameter of 10 mm or less to form a small drop in the solution to react, and the reaction filtrate is It is to provide a method for producing a high purity, fine manganese tetraoxide powder consisting of recycling.

1 is a graph showing the amount of hydrogen generated during the reaction in Experimental Example 1.

In the method for producing high purity, fine manganese tetraoxide of the present invention, the particle size of the metal manganese powder is 50 mesh or less, and during the reaction, the reactant is dispersed in a solution by heating and stirring, and an oxidizing gas containing oxygen or oxygen is dissolved in the solution. Injected through a nozzle having an inner diameter of 10 mm or less to form a small droplet to react, it characterized in that the reaction filtrate is recycled.

Manganese trioxide is prepared by dispersing a metal manganese powder in an aqueous solution using an amino acid or an ammonium salt as a reaction additive, and adding oxygen or oxygen-containing gas into the aqueous solution while heating and stirring it.

At this time, the metal manganese powder used as a raw material in the present invention uses finer powder finer than 50mesh. If the size of manganese powder is larger than this, unreacted manganese metal will be contained in the manganese trioxide powder produced due to inactivity.

The concentration of the dispersed metal manganese powder in the aqueous solution is preferably 50 to 250 g / l so that no unreacted material is formed.

As the reaction additive used in the present invention, conventionally used amino acids or ammonium salts are possible. Amino acids include glycine, glycyl glycine, α-alanine, glutamic acid. 1Na, DL-valine, L-asparagine, L-aspartic acid, β-alanine, L-lysine, glutamic acid, L-arginine, and α-amino isobutyl acid. Ammonium salt is preferably ammonium acetate (NH ₄ (C ₂ H ₃ O ₂ )).

In particular, the amino acid and ammonium acetate used in the present invention do not cause the problem of corrosion of the reaction vessel by anion, and the amount remaining in the produced manganese trioxide powder is not only small but also easily decomposed during drying of the final manganese trioxide powder. There is an advantage to using it.

The concentration of the amino acid or ammonium salt used as the reaction additive is preferably 0.03 to 1.0 mol / l. Outside this range, unreacted materials may be present.

In addition, the ratio of the reaction additive to the metal manganese is preferably 0.12 to 20 mol / kg. Outside this range, unreacted substances will be present in manganese trioxide.

After the metal manganese powder and the reaction additive are added to the aqueous solution, the stirring is performed by the influence of the reaction additive. Eventually, the effect is the same as using a large-size metal manganese powder in the beginning, the reactivity is eventually lowered and remains in the final product, causing a problem of lower purity. Therefore, it is necessary to dissolve the metal manganese by stirring during the reaction, so that the metal manganese powder does not entangle and is completely dissolved to form manganese hydroxide.

As such, the stirring speed should be at least 100 rpm when stirring to obtain a stirring effect.

On the other hand, as described above, the metal manganese powder is dissolved in the reaction solution to produce manganese hydroxide, and the produced manganese hydroxide is oxidized by oxygen in the oxygen or oxygen-containing gas. In order for the oxidation of manganese hydroxide present in the aqueous solution to occur, contact with the oxygen gas supplied as the oxidant and dissolution of the oxygen gas into the aqueous solution must occur effectively. Therefore, when a certain volume of oxygen gas is added, the method of increasing the contact area and dissolving the oxygen gas into the aqueous solution effectively is to make the gas bubble as small as possible when adding oxygen gas. Therefore, the size of the nozzle used for the injection of oxygen gas has a great influence on the oxidation reaction of manganese hydroxide, and the smaller the size of the nozzle, the shorter the oxidation reaction occurs.

In the present invention, the oxidation of the metal manganese powder is promoted by introducing an oxygen gas or a gas containing oxygen into the aqueous solution using a nozzle having an inner diameter of 10 mm or less.

At this time, the reaction temperature is suitable to prevent the unreacted substance from 20 to 100 ℃.

In the present invention, after removing the manganese trioxide after the reaction is completed, the filtrate is used again in the process for producing manganese trioxide. After the reaction, the remaining filtrate is left with distilled water and reaction additives. If it is thrown away, it causes problems of wastewater treatment. Therefore, by using it again, not only does it save the reaction raw materials, but it also eliminates the problem of wastewater treatment. During the reaction, distilled water is lost through evaporation, and additives are lost through decomposition, and the amount lost through evaporation and decomposition is added to each reaction to prepare a raw material solution. Can be.

Hydrogen is generated during the transition to manganese hydroxide and oxidation of manganese hydroxide by the following reactions:

Mn + 2H ₂ O → Mn (OH) ₂ + H ₂

3Mn (OH) ₂ + O ₂ → Mn ₃ O ₄ + 3H ₂ O

Therefore, the treatment of hydrogen generated during the reaction becomes very important in order to eliminate the risk of explosion that can occur during the reaction.

In an embodiment of the present invention, in order to effectively treat hydrogen, water vapor generated during the reaction and gas containing hydrogen are forcibly sucked through the exhaust port and discharged, and the intake amount is the amount of hydrogen generated and the amount of air included in the inhalation. When summing up, it is preferable to set the amount of hydrogen in the air to be equal to or less than the combustion point (about 4%) of hydrogen.

Hereinafter, the present invention will be described with reference to Examples. However, the present invention is not limited only to these Examples.

Example 1

20 L of water was added to a stainless reactor, and 3.0 kg of 50-mesh metal manganese powder and 250 g of glycine were added to prepare a reaction solution. While stirring the reaction solution at 600 r.p.m. using a stirrer, air was injected at 65 L / min through a nozzle having an inner diameter of 2 mm. After setting the temperature of the reactor at 80 ° C. for 5 hours, it was confirmed that a precipitate of manganese tetraoxide was formed. The manganese tetraoxide precipitate was filtered and dried to obtain 4.1 kg of ocher colored manganese tetraoxide powder having an average particle size distribution of 0.3 μm or less. At this time, unreacted metal manganese or manganese hydroxide was not found.

Examples 2 to 3

The same procedure as in Example 1 was repeated but the amount of manganese was increased to 4.5 and 6.0 kg, respectively. The amounts of the obtained manganese trioxide powder were 6.2 kg and 8.3 kg, respectively. At this time, unreacted metal manganese or manganese hydroxide was not found.

Comparative Example 1

The same procedure as in Example 1 was repeated but the reaction was increased by increasing the amount of manganese to 7.5 kg. The amount of the obtained manganese trioxide powder (yellow earth color) is 10.0 kg. When the amount of manganese is more than 7.5kg, that is, more than 250g / L, black metal manganese and white manganese hydroxide which are residual unreacted substances could be visually confirmed.

Examples 4-5

The same procedure as in Example 1 was repeated, but the amount of glycine was changed to 100 and 200 g, respectively. The amount of manganese tetraoxide obtained was 4.1 kg each. At this time, unreacted metal manganese or manganese hydroxide was not found.

Comparative Example 2

The same procedure as in Example 1 was repeated, but the reaction was carried out by changing the amount of glycine to 50 g. The amount of the obtained manganese trioxide powder is 3.7 kg. When the amount of glycine was 50 g or less, that is, 0.03 mol / l or less, black metal manganese and white manganese hydroxide, which were unreacted substances, were visually confirmed.

Examples 6-9

The same procedure as in Example 1 was repeated, but the reaction was carried out by changing the temperature of the reactor to 20, 40, 60, 100 ℃. The amount of manganese trioxide powder obtained is 4.1 kg. At this time, unreacted metal manganese or manganese hydroxide was not found.

Comparative Example 3

The same method as in Example 1 was repeated, but the reaction was carried out by changing the temperature of the reactor to 10 ° C. The amount of manganese tetraoxide powder obtained is 4.0 kg. When the reaction temperature was less than 10 ℃ it was possible to visually identify the remaining unreacted material of black metal manganese and white manganese hydroxide.

Examples 10-11

The same method as in Example 1 was repeated, but the reaction rate was changed to 400 and 200 rpm. The amount of manganese trioxide powder obtained is 4.1 kg. At this time, unreacted metal manganese or manganese hydroxide was not found.

Comparative Example 4

The same method as in Example 1 was repeated but the reaction rate was changed to 100 rpm. The amount of the obtained manganese trioxide powder is 3.8 kg. When the stirring speed was 100 rpm or less, black metal manganese and white manganese hydroxide, which were residual unreacted materials, were visually confirmed.

Examples 12-13

The same procedure as in Example 1 was repeated but the reaction was carried out by changing the amount of air to 20, 40 L / min. The amount of manganese trioxide powder obtained is 4.1 kg. At this time, unreacted metal manganese or manganese hydroxide was not found.

Comparative Example 5

The same procedure as in Example 1 was repeated but the reaction was carried out by changing the amount of air to 3 l / min. The amount of the obtained manganese trioxide powder is 3.7 kg. When the amount of air was 3 L / min or less, that is, 1.0 L / min / Kg based on the introduced metal manganese, residual unreacted substances of black manganese metal and white manganese hydroxide could be visually confirmed.

Examples 14-16

The same method as in Example 1 was repeated, but the reaction was performed by changing the inner diameter of the nozzle for blowing air to 4, 6, and 8 mm. The amount of manganese trioxide powder obtained is 4.1 kg. At this time, unreacted metal manganese or manganese hydroxide was not found.

Comparative Example 6

The same method as in Example 1 was repeated, but the reaction was performed by changing the inner diameter of the nozzle to 10 mm. The amount of the obtained manganese trioxide powder is 3.7 kg. Residual unreacted material of black manganese metal and white manganese hydroxide could be visually confirmed when the inner diameter of the nozzle was 10 mm or more.

Example 17

The amount of filtrate remaining after the reaction in Example 1 was about 13 L, and distilled water and glycine were added thereto and reacted in the same manner as in Example 1. At this time, the supplemented amount of distilled water was 7 L and the supplemented amount of glycine was 87.5 g. The amount of the obtained manganese trioxide powder was 4.1 kg, and the average particle size of the powder was 0.3 µm or less. In addition, no residual unreacted material was found.

Example 18

The amount of filtrate obtained in Example 17 was about 13 L, and the reaction was repeated in the same manner as in Example 17 using the filtrate. The amount of the obtained manganese trioxide powder was 4.1 kg, and the average particle size of the powder was 0.3 µm or less. There was also no residual unreacted material.

Example 19

As in Example 18, the process of reusing the filtrate was repeated 10 times. The amount of trimanganese trioxide powder obtained was 4.1 kg, and the average particle size of the powder was 0.3 µm or less. There was no residual unreacted material.

The reaction conditions of Examples 1 to 19 and Comparative Examples 1 to 6 and the yield and average particle size of the obtained manganese tetraoxide powder are shown in Table 1 below.

Manganese (kg) Solution temperature (℃) Glycine (g) Stirring Speed (rpm) Air volume (L / min) Nozzle Inner Diameter (mm) Manganese trioxide Unreacted substance yield(%) Average particle size (㎛) Manganese (g) Manganese Hydroxide (g) Example 1 3.0 80 250 600 65 2 98.5 0.2 - - Example 2 4.5 80 250 600 65 2 98.5 0.2 - - Example 3 6.0 80 250 600 65 2 98.5 0.2 - - Comparative Example 1 7.5 80 250 600 65 2 96.1 0.2 Example 4 3.0 80 100 600 65 2 98.5 0.2 - - Example 5 3.0 80 200 600 65 2 98.5 0.2 - - Comparative Example 2 3.0 80 50 600 65 2 88.9 0.2 Example 6 3.0 20 250 600 65 2 98.5 0.2 - - Example 7 3.0 40 250 600 65 2 98.5 0.2 - - Example 8 3.0 60 250 600 65 2 98.5 0.2 - - Example 9 3.0 100 250 600 65 2 98.5 0.2 - - Comparative Example 3 3.0 10 250 600 65 2 96.0 0.2 Example 10 3.0 80 250 200 65 2 98.5 0.2 - - Example 11 3.0 80 250 400 65 2 98.5 0.2 - - Comparative Example 4 3.0 80 250 100 65 2 91.3 0.2 Example 12 3.0 80 250 600 20 2 98.5 0.2 - - Example 13 3.0 80 250 600 40 2 98.5 0.2 - - Comparative Example 5 3.0 80 250 600 3 2 88.9 0.2 Example 14 3.0 80 250 600 65 4 98.5 0.2 - - Example 15 3.0 80 250 600 65 6 98.5 0.2 - - Example 16 3.0 80 250 600 65 8 98.5 0.2 - - Comparative Example 6 3.0 80 250 600 65 10 88.9 0.2 Example 17 3.0 80 87.5 600 65 2 98.5 0.2 - - Example 18 3.0 80 87.5 600 65 2 98.5 0.2 - - Example 19 3.0 80 87.5 600 65 2 98.5 0.2 - -

Examples 20-31

Using the same method as in Example 1, but reacted with a different reaction additive as shown in Table 2. After completion of the reaction, it was confirmed that manganese tetraoxide was formed without residual unreacted material. The amount and average particle size of the obtained manganese trioxide powder are shown in Table 2 below.

Example number Type of reaction additive Manganese Trioxide Powder Yield Average particle size (㎛) 20 Glycyl glycine 98% 0.3 21 α-alanine 98% 0.3 22 Glutamic Acid. 1Na 98% 0.3 23 DL-valine 98% 0.25 24 L-asparagine 98% 0.25 25 L-aspartic acid 98% 0.3 26 β-alanine 98% 0.2 27 L-Lysine 98% 0.3 28 Glutamic acid 98% 0.2 29 L-arginine 98% 0.2 30 α-amino isobutyl acid 98% 0.2 31 Ammonium acetate 98% 0.2

Experimental Example 1

In order to measure the amount of hydrogen generated during the reaction, the total amount of the reaction was reduced to 1/50 and reacted in the same manner as in Example 1. That is, the amount of metal manganese powder is 0.06 kg, distilled water is 400 ml, the amount of glycine is 5 g, and the amount of air is 1.3 L / min. After the reaction, it was confirmed that manganese trioxide was formed without any unreacted material.

At this time, the amount of hydrogen generated during the reaction is measured and shown in FIG. 1, the maximum amount of hydrogen during the reaction is 700 ml / min. The total amount of hydrogen generated during the reaction was 20,731.5 ml, which is almost the same as the theoretical value of 24,483.3 ml.

Example 32

Example 1 while forcibly discharging hydrogen to 900 L / min (intake amount of 4%, which is the combustion point of hydrogen in air is 880 L / min) based on the maximum value of hydrogen measured in Experimental Example 1 Reaction under the same conditions. The combustion did not occur as a result of igniting the exhausted hydrogen gas. The amount of manganese trioxide powder obtained is 4.1 kg. At this time, unreacted metal manganese or manganese hydroxide was not found.

Comparative Example 7

Using the same method as in Example 32, but changing the discharge of hydrogen to 600 l / min to react. The exhaust gas was ignited and burned. The amount of manganese trioxide powder obtained is 4.1 kg. At this time, unreacted metal manganese or manganese hydroxide was not found.

The present invention disperses the reactants in solution through agitation during the reaction, and promotes the reaction by improving the method of adding oxidizing gas, thereby reducing manganese trioxide powder in a short time using a smaller amount of the reaction additive at higher manganese metal concentrations. The manganese trioxide powder obtained in this way contains no unreacted substance, and has an average particle size of 0.3 µm or less and is a fine, high purity manganese trioxide powder. In addition, in the present invention, the reaction filtrate can be recycled to complete the reaction in a short time by using a smaller amount of the reaction additive, and economically by eliminating the contamination problem caused by the discharge of the filtrate as well as reducing the amount of the reaction additive. It can manufacture.

Claims (10)

In the method for producing manganese trioxide powder by dispersing the metal manganese powder in an aqueous solution with a reaction additive selected from amino acids or water-soluble ammonium salt and oxidizing the metal manganese powder with an oxidizing gas containing oxygen or oxygen while heating and stirring it. The high purity consisting of a metal manganese powder having a particle size of 50 mesh or less, oxygen or oxygen-containing oxidizing gas is introduced into the solution through a nozzle having an inner diameter of 10 mm or less, formed into small droplets, and recycled, and the reaction filtrate is recycled. Method for preparing fine tetramanganese trioxide powder. The method for producing manganese trioxide according to claim 1, wherein the concentration of the metal manganese powder dispersed in the aqueous solution is 50 to 250 g / L. The amino acid of claim 1, wherein the amino acid is glycine, glycyl glycine, α-alanine, glutamic acid. 1Na, DL-valine, L-asparagine, L-aspartic acid, β-alanine, L-lysine, glutamic acid, L-arginine, and A process for producing manganese trioxide, wherein the water-soluble ammonium salt is selected from α-amino isobutyl acid and the water-soluble ammonium salt is ammonium acetate (NH ₄ (C ₂ H ₃ O ₂ )). The method for producing manganese trioxide according to claim 1, wherein the concentration of amino acid or ammonium salt is from 0.03 to 1.0 mol / l. The method for producing manganese trioxide according to claim 1, wherein the ratio of the reaction additive to the manganese metal is 0.12 to 20 mol / kg. The method for producing manganese trioxide according to claim 1, wherein the reaction temperature is 20 to 100 ° C. The method of claim 1, wherein the rate of stirring during the reaction is at least 100 rpm or more. The method for producing manganese trioxide according to claim 1, wherein the hydrogen generated during the reaction is discharged to the outside through inhalation. The suction amount of the generated hydrogen is set to an intake amount such that the amount of hydrogen in the air is equal to or less than the combustion point of hydrogen when the amount of generated hydrogen and the amount of air included in the suction are added together. Method of manufacturing manganese trioxide. The method for producing manganese trioxide according to claim 1, wherein an amount of oxygen or oxygen-containing gas per kilogram of manganese metal powder is 1.0 L / min or more.