JPS5820729A - Preparation of manganese oxide - Google Patents

Abstract

PURPOSE:To prepare manganese oxide fine powder having controlled degree of oxidation and usable as a raw material of ferrite, by adding an oxidizing agent to a suspension of manganese hydroxide obtained by the reaction of an aqueous solution of manganese sulfate with ammonia water. CONSTITUTION:Ammonia water is added to an aqueous solution of manganese sulfate to obtain a suspension of manganese hydroxide. An oxidizing agent such as H2O2, O2, air, etc. is added to the suspension. The degree of oxidation of the resultant manganese oxide can be controlled easily by adjusting the concentration of the oxidizing agent when the agent is liquid, or by adjusting the blowing rate or time of the agent when it is gaseous. The oxidation is carried out until the oxidation degree (the value of x in the formula MnOx) reaches 1.3-1.5 which is suitable range as the raw material of ferrite, and the resultant manganese oxide is filtered and dried to obtain desired fine particles having relatively sharp particle size distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION The claimed invention relates to a method for producing manganese oxide, and more specifically, the invention relates to a method for producing manganese oxide, which has an oxidation degree of 1.3 and is particularly suitable as a raw material for ferrite.
1.5 relates to a method for economically producing oxidized χ/gun in the form of fine particles.

Conventionally, manganese oxide has been produced by many methods, but these methods have the following problems. For example, a method using a dissociation reaction of manganese oxide has a high dissociation temperature of 940° C. or higher.

Furthermore, when the reaction is allowed to proceed at low temperatures, there are drawbacks such as the need for hydrogen. Furthermore, manganese oxide can be obtained from manganese carbonate, manganese hydroxide, manganese chloride, etc., but heating at a high temperature of 1000°C or higher is required to remove the volatile substances of the hexasalt. .

Moreover, in addition to being uneconomical due to heating at pot temperature, the above method does not require manganese oxide to be produced which has a controlled oxidation degree and consists of fine particles, which is required for use as a raw material for ferrite. It also has the disadvantage that it is extremely difficult to obtain.

In other words, in order to obtain manganese oxide with an oxidation degree of 1.3 to 1.5, which is suitable as a ferrite raw material, by the conventional method, it is necessary to control the operating conditions in the heating step extremely closely, which is virtually impossible. In addition, to obtain fine manganese oxide, another process is required.

Therefore, the purpose of the present invention is to eliminate the above drawbacks,
A method for economically producing manganese oxide in the form of fine particles with a controlled degree of oxidation that can be used as a raw material for ferrite;
It is in providing the law.

The present inventors conducted research to achieve this objective, and found that a suspension of manganese hydroxide was formed by the reaction between an aqueous solution of manganese sulfate and aqueous ammonia, and K in the soybean solution was directly absorbed. By adding an oxidizing agent, manganese oxide can be generated while easily controlling oxidizing flies, and then,
It has been found that fine manganide having a desired degree of oxidation can be obtained by simply filtering and drying. Thus, according to the invention, reacting an aqueous manganese sulfate solution with aqueous ammonia to form a suspension of manganese hydroxide
Said lIi! The method is characterized by comprising a step of adding an oxidizing agent to the suspension to obtain manganese oxide with a desired degree of oxidation, and a step of filtering and drying the manganese oxide.
．． ! 1 to 1.5 is provided. (In addition, the candy called oxidation degree used in this specification is
It means the value of X when manganese oxide is expressed as MnOx. ) In the present invention, the step of reacting an aqueous manganese sulfate solution with aqueous ammonia to form a suspension of manganese hydroxide is carried out under conditions such that manganese hydroxide is efficiently produced and does not contain any impurities. It should be done in Therefore, the reaction is performed at a Mn concentration of 100 to 220 f'/l.
It is preferable to add 1 to 6N aqueous ammonia to the sulfuric acid urine solution under conditions of pH 9.0 to 10.2. Mn in manganese sulfate aqueous solution 9 degrees is 10
If it is less than 0171, productivity and reaction efficiency will be poor, and if it is less than 220
There will be manganese sulfate that does not dissolve above t/. The lower the ammonia water is, the better it is because there will be no impurities in the manganese hydroxide produced, but 1N
If it is less than 6N, the productivity will be poor, while if it is more than 6N, more impurities will be included, so it is preferable to use a concentration of 1N to 6N.

Moreover, the reason why g) H is set to 9.0 to 10.2 is to efficiently oxidize manganese. In other words, when the pH is below 9.0, the efficiency of manganese oxidation decreases, and on the other hand, when the pH is below 10. When the value is 2 or more, impurities such as alkali and alkaline earth contained in the manganese sulfate/aqueous solution increase, and as is well known, part of the manganese hydroxide becomes complex ions and becomes difficult to absorb in the bath. This is not preferable because it reduces the recovery rate of manganese.

Next, in the method of the present invention, manganese oxide is produced by directly adding an oxidizing agent to the suspension of manganese hydroxide obtained as described above. Various oxidizing agents can be used as the oxidizing agent, but in consideration of reactivity with manganese hydroxide and subsequent processing steps, it is preferable to use hydrogen peroxide, oxygen, or air. It is. Thus, according to the present invention, when a liquid oxidizing agent is used, the degree of oxidation of the obtained manganese oxide can be easily controlled by controlling its concentration.

For example, when using hydrogen peroxide, the concentration is between 1 and
By setting the concentration to 15 percent, manganese oxide with a desired degree of oxidation (1.3 to 1.5) can be obtained. If the concentration of the hydrogen peroxide solution is more than 15/volume-cent concentration, it will become vno2, whereas if it is less than 1 percent concentration, the productivity will be poor and it will not be practical. Further, when oxygen or air is used as an oxidizing agent, the degree of oxidation of the obtained manganese oxide can be easily controlled by adjusting the blowing speed and blowing time. Note that a mixture of a plurality of oxidizing agents can be used as the oxidizing agent.

Finally, in the method of the present invention, the manganese oxide obtained by oxidizing to a desired degree of oxidation by adding an oxidizing agent is filtered and dried.

In this manner, according to the method of the present invention, manganese oxide having a desired degree of oxidation can be obtained in a short time and at a low temperature (room temperature). In addition, since it is processed at a high concentration, it is suitable for mass production.

Furthermore, since the fine particles of manganese hydroxide are oxidized as they are, the obtained manganese oxide is always in a uniform state and has a fine shape with a relatively uniform particle size structure of 1 to 5 μm. In addition, the manganese oxide obtained by the present invention has the advantage that it is fine particles and does not require steps such as calcining, so it is suitable as a raw material for ferrite.

The accompanying drawing shows an example of a suitable apparatus for carrying out the method of the invention. When a manganese sulfate water bath solution and ammonia water are reacted, the manganese sulfate aqueous solution is charged into the apparatus equipped with a stirrer 1 and a baffle plate 4, while ammonia water is introduced through a nozzle 2. When oxidizing a suspension of manganese hydroxide, a gas such as oxygen or air is blown through the gas blowing nozzle 3, or a liquid oxidizing agent such as aqueous ammonia is introduced through the nozzle 2. Alternatively, these oxidizing agents are mixed and introduced using nozzles 2 and 3 in combination. The product will be removed from the drain port 5. Examples of the invention are listed below.

Example 1 A manganese sulfate aqueous solution with a Mn concentration of 150 tt/l was prepared.

Next, the above-described aqueous solution of manganese sulfate was placed in a reaction tank equipped with a stirrer as shown in the figure, and 2N aqueous ammonia was added little by little. Add ammonia water in this way,
After obtaining white manganese hydroxide at pH 9.8, while stirring was continued, hydrogen peroxide solution with a concentration of 6/9 cents was added little by little to oxidize the manganese hydroxide.

The brown product obtained by the oxidation reaction was extracted from No. 5, filtered, washed with water, and dried at a temperature of 140°C. As a result, fine particles of manganese oxide having the composition shown in Table 1 were obtained. It was done.

Table 1 In addition, T, Mn (Tota
lMn) is the Mn grade (Mn content) of the produced manganese oxide expressed in weight %.

Example 2: Un a & 150 f/J of sulfuric acid 9 N f7 aqueous solution 41
After creating a white precipitate in the reaction tank in the same manner as in Example 1, 201. JO160, stirred for 90 minutes, and the resulting oxidized manganese 7 was mixed with KN as in Example 1.
After filtering, washing with water, and drying, fine particles of manganese oxide having the composition shown in Table 2 were obtained.

2nd #! As is clear from the above, the composition of the oxidized manganese varies depending on the Km conditions (injection amount and time), and in this example, A2 to A7 are the optimum conditions.

M211i! Example 3: The same operation as in Example 2 was repeated. However, an oxidation reaction was carried out for 90,180 minutes using K9 gas instead of 02 gas, followed by temporary drying, and as a result, fine particles of oxidized manganese having the composition shown in the third section were obtained. It was done.

As in Example 2, the composition of manganese oxide becomes favorable depending on the oxidation conditions, and in this example, the composition of manganese oxide becomes favorable depending on the oxidation conditions.
It was found that the desired degree of oxidation could be obtained under the conditions shown in #! 3 Table 4, Brief outline of the drawings & 114 □ The drawings are cross-section diagrams of the shank section suitable for applying the method of the present invention to the dormitory.

2; liquid introduction nozzle; 3; f-s blowing nozzle.

Claims (1)

[Claims] 111 A method for producing manganese oxide having an M degree of 1.3 to 1.5, which comprises reacting an aqueous solution of manganese sulfate with aqueous ammonia to form a suspension of manganese hydroxide. The method comprises the following steps: adding an oxidizing agent to the suspension to obtain manganese oxide with a desired degree of oxidation, and filtering and drying the manganese oxide. (2) The reaction between manganese sulfate aqueous solution and ammonia water is
The method for producing manganese oxide according to the above item (1), which is carried out by adding 1 to 6N ammonia water to Mn concentration [1DO to 220 f/l, and performing under the conditions of G) H9-0 to 10.2. . 131 The method for producing manganese oxide according to item f11 or item (21), wherein the oxidizing agent is hydrogen peroxide, oxygen, or air.