JPS59182233A - Oxidation of manganese carbonate to manganese dioxide for cell - Google Patents

Abstract

PURPOSE:To prepare a high-quality manganese dioxide for cell, having low beta- content, by oxidizing heavy manganese carbonate at specific temperature and pressure with an oxidizing gas comprising a steam-containing oxygen gas or dried oxygen gas. CONSTITUTION:Heavy manganese carbonate is prepared e.g. by the precipitation reaction of a soluble manganese salt with a soluble carbonate. The produced heavy manganese carbonate is oxidized under a reaction pressure of 4- 20 atm at 275-350 deg.C using steam-containing oxygen gas or dried oxygen gas as the oxidizing gas. The objective chemically synthesized manganese dioxide for cell, having an MnO2-content of >=88% and beta-content in the produced MnO2 of <=20% can be produced by this process. The dry cell manufactured by using the chemically synthesized manganese dioxide as a raw material is superior to those manufactured from electrolytic manganese dioxide in the continuous discharge characteristics, intermittent discharge characteristics, etc.

Description

Detailed Description of the Invention Chemically synthesized mankan dioxide is produced by oxidizing heavy mankan carbonate, which is generally produced by the carbamate method or by soluble salt addition and precipitation reaction from soluble carbonate, to obtain crude MnO2, which is then treated with dilute sulfuric acid, etc. Then, acid treatment is performed to dissolve unreacted MnC0, improve the quality of MnO, and reduce the generated MnO2'
eActivate it for use in batteries, or add acid, seed salt to crude MnO2,
and Na(30) are added and reacted, and the Mn0t produced by the chlorate reaction is incorporated into the internal surface of the crude Mn0t, resulting in heavy MnO with good filling properties. ( Electrochemistry vol 49, page 766 (1981
)) However, in general, oxidation of MnCO5 can be carried out using air at a temperature of around 320°C, and the oxidation grade is also Mn0t.
The reaction stopped at around 5%, and around 0.15% of MnC remained in the reaction product, and the reaction took a long time.

(rwnganjs4:TijotMr uques
(by s, n'fehs 159 ptye, electrochemistry vol. 149.175 (1981)) In other words, the oxidation method currently in common use has a low oxidation grade (MnC0
, has the disadvantage of low utilization rate, and furthermore, residual Mn during processing
Since CO5 is extracted as seed salt, the produced MnO has the disadvantage of being extremely light. Furthermore, in order to make the crude Mn0t into Mn0t with good filling properties, acid, seed salt and Nh
C! ! Ds tl-MnO, which is caused by a chlorate reaction, also when performing a weighting treatment by addition reaction.

The disadvantage is that unless the production ratio of is increased, the degree of weighting is low. (Electrochemistry vol 149 □ 766 pages (1981
)) As a method to improve this, there is a method of using lightly humidified humidified oxygen of 4 atmospheres or less for heavy MnC0 by the carbamate method. (Electrochemistry vol 4976
6 (1981)) The same method produces MnO, the quality is 90
It is an excellent method that reaches ~91% and also reduces residual MnCO3 to 3-4%. However, the method produces Mn
The issue of the β-formation rate of O2 remains unresolved, and only points out that if pressurized oxygen of 4 atmospheres or more is used, there is a problem in that some of the produced MnO2 becomes β-form.

Regarding this problem, the reaction pressure during oxidation and the generated MnO,
The relationship between the β-formation rate and the β-formation rate of MnO.

Since there is no research on the effect on the discharge characteristics, we conducted a study to clarify this problem.

That is, the inventors prepared Mn5O+ solution and (NH4)2COs
Using MnCO3 with a tap density of 2.36 shown in Table 1, which was obtained by charging the solution in parallel while stirring, the reaction temperature was 325°C, which is considered to be the optimum temperature, for oxidation.
Assuming that the water vapor partial pressure of oxygen gas is 1 atm, the relationship between the reaction pressure, the quality of MnO2 produced, and the β-formation rate is determined by the reaction time of 3.
Considered at regular intervals. Regarding the β-formation rate of MnO2, the amorphous MnO without β-form, which is also listed in Table 1, and β-Mn02 obtained by thermal decomposition of Mn (NOx)t and further dehydration are used as standard. As a sample, M
The calibration curve shown in Figure 1 was created from the relationship between the mixing ratio of both samples and the area on the base line of the β-MnO2 peak using an O tube using a step scan method. .

Table 1 As a result, the reaction pressure, the quality of produced Mn0t, and produced MnO.

The results shown in FIG. 2 were obtained regarding the relationship between the β-forming rate of .

Next, each sample of 1009 with a stepwise difference in β-forming rate from 5 to 25% was treated with INHNos for 3 hours, washed and dried, and synthesized by a conventional method using an aqueous solution of 32% ZNC 14.1% NH 4 cc as an electrolyte. Acetylene black in agent 12%
With the Mn01 filling rate constant at 249, a D size dry battery was made, and a 4Ω continuous discharge test was conducted.
The retention time up to V was determined and compared with electrolytic mankan dioxide under the same conditions, and the relationship between the β-formation rate and retention time was summarized in a diagram.The results are shown in Figure 3.0 Based on the above results, acid treatment The relationship between the β-forming rate and the retention time of Mn0t is almost unchanged up to the β-forming rate of 1%, and the retention time is 17 to 18 hours, and the discharge efficiency is in the range of 20% to 7y%.
This value was superior to the retention time of electrolytic MnO+, which was 16.8 hours. However, when the β-formation rate was 20% or more, the retention time sharply decreased. That is, although β-Mn02 is originally inert and is said to have low discharge efficiency, 1. As for MnO2, which is the oxidation of MnCO3, the effect was found to be at least extremely small and not a problem up to a β-formation rate of 20%. This is considered to be due to the special characteristics of this chemically synthesized MnO2.

Next, looking back at the relationship between oxidation pressure, reaction time, and the quality of MnO2 produced, it is as shown in Figure 4. At 5 atm, the required time to reach 90% or more of MnO quality is 3 hours. On the other hand, the β-type conversion rate is 6%, but at 20 atm, MnO reaches 88% or more in 91 hours as shown in Figure 5, and β
Although the molding rate was only 13%, the oxidation grade reached Mn0t88% or higher even with dry oxygen, regardless of moist oxygen. Furthermore, when the reaction pressure is ambient pressure, the reaction time is
Even if lr was used for 1 hour, the quality of the generated MnOx was 90% or more, but the β-forming rate also reached 21%.

Overall, heavy MnCO for the purpose of MnO2 for batteries
As the oxidation method of No. 5, 02 scum containing water vapor or dry O, scum is used as the oxidation scum, and the reaction pressure is 4 to 2.
In the range of 0 atm (gauge pressure), the reaction temperature is 275°C/
It is concluded that the test should be carried out at -350°C.

Figure 6 shows the humidity level 02 (PH20
:'UA) shows the reaction temperature, Mnot grade of the oxidation product, and its β-form conversion rate, assuming an oxidation time of 2 hours.
This result showed that the reaction temperature should be in the range of 275-350°C.

This method has not been studied at all so far, and can be said to be a completely new method.

Examples of rates and methods will be described below.

Example 1 510 kg of heavy MnCO with a tap density of 2.58 was charged in a horizontal forced stirring and pushing type cylindrical electric furnace, and under stirring, the reaction temperature was 315°C to 325°C, the reaction pressure was 15 atm, and the water vapor partial pressure was increased. Oxidation was performed using humid oxygen at 1 atm for 2 hours.

As a result, 7.70 kg of MnO and manganese dioxide having a grade of 9065% were obtained. Next, this manganese dioxide 7.7k
1N-HNO31OA' was added to the reaction temperature of 85.
The mixture was treated at ℃ for 1 hour, washed with water, and dried to obtain 39 kg of purified man camphor dioxide having a grade of 3% MnO, 93J. The MnO2β conversion rate of the oxidation reaction product was 12%, and the analytical values and physical property values after treatment with nitric acid were as shown in Table 1.

Next, using 200 g of this acid-treated sample, acetylene black, 32% ZnCl, 1% NI (4CI2/aqueous solution) was used as an electrolyte, and acetylene black 12
．． 0%, 1 piece of mankan dioxide 24g as dry cell 8
4 Ω continuous discharge using 4 Ω each, 4 Ω
An intermittent discharge test was conducted and the results were compared with those prepared under the same conditions using electrolytic mankan dioxide alone. The results are as follows. The holding time of 0.85V and the discharge efficiency are as shown in Figure 7. Both intermittent discharge was superior to electrolytic mankan dioxide.

Summary of Example Results Used MnCO310kg (Mu 46.9%, tap density 2.58) 15 atmospheres 02 (Puzol, 0) 31
Yield after oxidation at 5 to 325°C for 2 hours: 7.70, 9 oxide quality and β-formation rate Total Mn: 60.7%, MnO: 290.5%, β-formation rate: 1
2%INHNO, yield and quality of processed material...7
．． 39kl? Discharge test results A, B 12% electrolyte Znet, 32%, Nagi α, 1% mankan dioxide 249 charge 4Ω continuous discharge Holding time to 0.85V 17.8hr
s discharge efficiency % Comparative electrolytic mankan dioxide 16.8 hrs discharge efficiency
% 4Ω intermittent discharge Holding time to 0.85V 22.7 hours
rs (0.5hr/day) Discharge efficiency
% comparative electrolytic mankan dioxide 19.4 hrs
Discharge efficiency % Example 2 Example 1: heavy MnCO3 with a tap density of 2.36
In the same reactor as above, the temperature was 315-325℃ and the water vapor partial pressure was 1.
．． 3 with humid oxygen at 0 atm and total pressure 5.0 atm (gauge pressure)
The reaction was carried out under stirring for hours to obtain 71 kg of mankampf dioxide with a MnO2 content of 91%. Next, add MnCO to this oxide.
52.2 kg 'c was added, and further 7% HNO3101 was added, stirred and heated to 75°C, and powdered NaNOS 9009
f It was added while maintaining the temperature at 75°C. After the addition, the mixture was further stirred for 2 hours, filtered, washed with water, and dried at 100°C to obtain 9.40 kg of heavy manganese dioxide.

The β-forming rate during the oxidation reaction, the quality and physical properties of the heavy mankan dioxide were as follows.

In addition, 2009' of heavy mankan dioxide was collected, mixed with acetylene black, and mixed with 32% ZnC4 and 1% NH.
Using 4CL electrolytic solution, a mixture was prepared so that the acetylene black content in the mixture was 12%, and 8 dry batteries were manufactured so that each battery contained 24 g of mankan dioxide, and the batteries were electrolyzed under the same conditions. The results of comparing the 4Ω continuous discharge and intermittent discharge characteristics with manganese dioxide are as follows. This synthetic heavy manganese dioxide shows superior characteristics than the electrolytic product, and the MnO2 production ratio due to the chlorate reaction is approximately 20 %, but reached a greater tap density than the electrolytic product.

Example 2. Summary of results MnC0B used 10 kg (Mn46.8%, tap density 2.36) 5 atm (Puto 1.0) 02
Oxide yield, quality, and β-formation rate obtained by 3-hour oxidation (315-325°C) at 7.71 kg, MnO291.0% β-formation rate 6%
MnCO5 (Mn 46.8%) 2.2kl? , 7%H
Amount and quality after reaction with addition of N0.10 l and addition of 10.900 g of NaC Physical properties Discharge test results A, B 12% electrolyte ZnCLL 32%, NH4CJ,
i% Mancan dioxide 24N charge 4Ω continuous discharge 17.9 hrs Comparative electrolytic Mancan dioxide 16.8 hrs 4Ω intermittent discharge
22.8 hrs comparative electrolytic mankan dioxide
19.2 hours

[Brief explanation of drawings]

Figure 1 shows the β-MnOt mixing ratio and β-Mr1 in
The relationship between the area of the 0t peak, Figure 2 shows the relationship between the oxidation pressure of MnCO3 and the Mnot% and β-M1102 equivalent content of the product (reaction time 3 hours), and Figure 3 shows the relationship between β-Mn02% and the D size dry battery. FIG. 4 shows the relationship between the holding time of 4Ω continuous discharge and the reaction time during oxidation at 5 atm, the MnO2 grade, and the β conversion rate. (PH201, 0 atm, 320℃) 5th
The figure shows the oxidation pressure, seed 0□ grade, and β conversion rate (320℃) during oxidation with dry oxygen at a reaction time of 1 hour, and Figure 6 shows 15
Oxidation temperature during oxidation at atmospheric pressure, Mn01 grade and β conversion rate (
PH201, 0 atm, reaction time 2 hours), Figure 7 shows Zn
CnC type D size dry cell 4Ω continuous and 4Ω intermittent (0,
5Hr/da7) Discharge performance of discharge (24g charge): 17; Written amendment (spontaneous), 2-/ May H, 1980, Commissioner of the Patent Office Kazu Wakasugi Failure 1, Indication of case Patent application No. 58-53197 2, Title of invention Oxidation of manganese carbonate to manganese dioxide for batteries Method. 3. Relationship with the case of the person making the amendment Patent applicant address: 3-12-2 Nihonbashi, Chuo-ku, Tokyo Name: Outside of Toho Zinc Co., Ltd. Name 4: Agent A column for a brief explanation of the drawing, and Figures 3, 4, 6, and 7 of the attached drawings for clarity. 6. Contents of amendment In the detailed statement, there are four deficiencies in the following sections, so we will amend them. (1) Description Correct "Gyore" on the 5th line of the 2nd page to "Gyomarare", and correct "Stop" on the 6th line to "Stop". (2) Amend "do" in the fifth line from the bottom of the second page of the specification to "do". (3) Line 1 on the 7th line from the 3rd purchase on the statement has stopped.”
to "stopped", "to make clear" in line 11 to "to make clear", and "density" in line 14 to [density ('i', D)J]. To do. (4) “Different” in the seventh line from the bottom of page 4 of the specification should be corrected to “different”. (5) “Relationship between” on the second line from the fifth purchase on the statement
to "relationship i with time and discharge efficiency", and "retention time 17 to 18 hours" in the 6th line to "retention time 18.5 to 19 hours"
Then, from the father, in the first line, "stopping" is corrected to "stopping". (6) “Things to be carried out” on the 10th line from the 6th purchase in the specification are changed to “Things to be carried out” from the father on the 7th line.
``should be within the scope'' becomes ``should be within the scope'', ``hasn't been done'' in the 5th line from the bottom is changed to ``hasn't been done'', and ``state'' in the 3rd line from the bottom to ``state'' Correct each. (7) In the 9th and 10th lines from the top of page 7 of the specification W, the phrase “as in Table 1” was replaced with “Example 1 below.”
．． The results are shown in the summary. ” and correct it. (8) “As below” in the third line from the bottom of page 7 of the specification
will be corrected “as shown in the summary below”. (9) "Summary of results of Examples" on the top line of page 1 of the specification will be corrected to "Example 1. Summary of Results." (Correct the record from line 13 to line 20 on page 8 of the IQ specification as follows. 4Ω continuous discharge Holding time to 0.85V 19.0
hrs discharge efficiency 72.6% Comparative electrolytic manganese dioxide 16.8hrs discharge efficiency 70.2% 4Ω intermittent discharge Holding time up to 0.85■ 22
．． 7hrs (0.5br/day) Discharge efficiency
89.3% comparative electrolytic manganese dioxide 19.4
hrs discharge efficiency 79.7% Accurate "It was as follows" in the 9th to 12th line of the statement will be corrected to "as shown in Example 2. Result summary below." tlB "As below" in the first line from the bottom of page 9 of the specification
will be corrected “as shown in the summary below”. αken The "Relationship with retention time" in the 6th line from the top of page 11 of the specification will be corrected to "Relationship with retention time and discharge efficiency." I. Figures 3, 4, 6, and 7 of the drawings attached to the specification are amended as shown in the attached drawings.

Claims (1)

[Claims] As a method for oxidizing heavy mancan carbonate to manganese dioxide for batteries, oxygen gas containing water vapor or dry oxygen scum is used, and the reaction conditions are a total pressure of 4 atmospheres or more (gauge pressure) 2
At reaction pressure below 0 atmospheres, reaction temperature from 275℃ to 350℃
The reaction was carried out within a range of MnO288% or more, and the produced M
A method for oxidizing mankan carbonate for the purpose of producing chemically synthesized manganese dioxide for batteries with a β-form conversion rate of nO2 of 4% or less.