JPS60103192A - Treatment of material accumulated in electrolytic cell - Google Patents

Abstract

PURPOSE:To recover efficiently product MnO2 and Mn oxide by adding hot water to the material accumulated in an electrolytic cell in the stage of producing electrolytic MnO2, adding water to the solid component recovered by a solid- liquid sepn. and stirring the mixture then recovering further the solid component by the solid-liquid sepn. thereby removing easily gypsum, etc. from the accumulated material described above. CONSTITUTION:The accumulated material consisting of a mixture composed of product MnO2 in addition to the wax, gypsum and Mn oxide produced in an electrlytic cell when the Mn oxide is suspended and electrolytic MnO2 is produced by a slurry method. More specifically, the accumulated material is separated and recovered from the electrolytic cell and thereafter water is added and th material is heated to >=70 deg.C to melt the wax, etc. and to float the same on the surface of the hot water; at the same time, CaSO4.2H2O is dissolved and extracted in the hot water. Such treated liquid is then subjected to a solid- liquid sepn. to separate the wax and CaSO4.2H2O. Water is added to the resultant sludge-like accumulated material and after thorough stirring, the material is subjected to the solid-liquid sepn., by which the product MnO2 and the raw material Mn oxide are recovered at a good yield.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for treating accumulated material in an electrolytic cell, and its purpose is to easily treat the accumulated material in an electrolytic cell during production of electrolytic manganese dioxide. In the electrolysis of electrolytic manganese dioxide in which manganese is recovered and reused, a method is known in which manganese oxide is suspended and electrolyzed in a manganese sulfate solution as an electrolytic solution (hereinafter referred to as the slurry method).

Slurry method 4.11 can double the current efficiency compared to the usual method of electrolysis at °C using only a manganese sulfate solution as an electrolyte, and is therefore an extremely superior method in practice.

However, as mentioned above, in the slurry method, the electrolyte is mixed with manganese oxide and electrolyzed with vinegar, so if continuous operation is continued for a long time, manganese oxide will accumulate in the electrolytic cell as the days of electrolysis pass. Therefore, in the slurry method, the electrolysis is stopped periodically or as needed, the electrolyte is drained, and the electrode plates are removed to remove the buildup in the tank, but this buildup has the following problems. Therefore, it is difficult to use this as a manganese oxide. That is, although manganese sulfate, which is an electrolyte, is originally of high purity, there is a trace amount of Ca present. . This Ca
+1 is CaS when the melt W reaches 1 degree or more in the electrolyte.
Forms O4 and also exists as an anhydrous salt, but % aqueous salt, 2
Water salts are precipitated primarily as dihydrate salts, which are included in the deposits in the electrolytic cell.

In addition, paraffin, wax, etc. are added to the electrolytic cell to prevent evaporation of the liquid during electrolytic treatment. These waxes have a melting point (one tap) of 55 to 70°C, and at a temperature of 90 to 95°C during electrolysis, they all melt and float to the surface of the electrolyte, covering the surface of the electrolyte and preventing evaporation. It's fulfilling its share.

However, these waxes flow over a wide area within the electrolytic cell due to the convection of the electrolyte, and some of them mix with the manganese oxide suspended in the electrolyte, and as the liquid temperature drops, manganese is released.・I\ solidified in the oxide and was included in the accumulation of the electrolytic cell (color).

Furthermore, partially exfoliated fragments and powder of manganese dioxide, which is a product deposited on the electrode plates by electrolysis, are also included in the accumulation of the electrolytic cell. Since it is directly related, it is necessary to recover it in one curve.

As a result of research on the electrolytic cell accumulation produced by the slurry method for manufacturing electrolytic manganese dioxide, the inventors of the present invention have found that by adopting the structure described in the claims, waxes, etc., can be removed from the electrolytic cell accumulation. The product manganese dioxide and manganese oxide could be recovered by simple removal.

That is, the present invention is a method for producing electrolytic manganese dioxide by suspending manganese oxide, in which hot water of 70'C or higher is added to the accumulated material in an electrolytic cell.

It is characterized by consisting of a first step in which solid content is recovered by solid-liquid separation, and a second step in which water is added to the solid content recovered in the first step and the solid content is agitated, and then the solid content is recovered by solid-liquid separation. This is a method for disposing of the accumulated material in the electric IQ tank.

As mentioned above, when electrolytic manganese dioxide is produced by the slurry method, the accumulation that occurs in the electrolytic cell is a mixture consisting of waxes, gypsum, manganese oxide, and product manganese dioxide. In the first step, water is added to the accumulated material recovered from the electrolytic cell and heated to 70°C or higher.

Since waxes generally have Ill and p of 55 to 700G, the waxes that have been rubbed into the manganese oxide and solidified can be separated from the solid matter and floated to the surface of the hot water for separation. Instead of adding water with a string, it is also possible to directly add hot water at 70°C or higher, but in this case, the hot water should be as high as possible, taking into account the amount of heat absorbed by the entire accumulation.

However, it is better to add hot water directly, but rather add water to 1+1
This method is advantageous because it is easy to handle and can easily be heated to a temperature of 90° C. or higher.

In addition, this hydrothermal treatment allows -(CaSO4.2H2O present in the accumulation to be dissolved and extracted in hot water.

That is, the solubility of Ca5O, # 2 H2O is M n
In the presence of SO4 or H2SO4, there is a positive temperature dependence, e.g.
The solubility of CaSO4・211□O in Oi solution is 20
℃ 9 -CO-5Ca is 7 stones, while 80
IL at ℃! 37 Ca, and the solubility of CaSO4.211□O in 0.7 mol H2SO4 solution 6 is o, sg'fi' at 20°C, while it is 2 at 80°C. , OCa9/13-C;I'J
Z+ (see Japanese Patent Publication No. 18661/1983).

The hot water treatment requires the use of a considerable amount of hot water in order to reduce the stickiness of MnSO4' and 142sO4. 1-
It is desirable to use a small amount of hot water once: 1: 2013 + 'r' per IICg of accumulated material,
IJ is effective in removing wax ribs I by increasing the number of treatments.

The accumulated product from which wax and Ca5O, .2112U have been dissolved and removed as described above is recovered by solid-liquid separation.

Solid-liquid separation in the string can be carried out by either the θi filtration method or decantation method, which is an alternative to the conventional method.

In this case, if there is any manganese dioxide product that has peeled off from the electrode in the accumulated material, remove it and store it separately.

In addition, after solid-liquid separation in the first step, 11J'I and water are injected, and if an oil-like pattern is observed on the surface, the hot water treatment in the first step is performed. is desirable.

The accumulated material recovered from the hot water in the first step is in the form of sludge and contains Ca5Q1. Stir thoroughly to 1/L.

In the second step, the temperature of the water used may be around room temperature, but it is necessary to use a large amount of water.

That is, the solubility iQ' of CaS'04.2 H2O in water
There is almost no influence of temperature on r degrees, which is approximately 2 degrees/l-1.
It is said to be a 2o swamp. Therefore, the accumulation 11 [! /This D
If it contains 500' of CaSO4/2H2o (according to research by unexploded IJJ people, CaSO4 in the
' 2 H2O is thought to be in the range of 5 to 40%, and in reality the content is lower than the above value), :1f1 product 11r
The amount of water used for one treatment is 150 to 500 g.
C4 "It is desirable to set it to 11 degrees, '; j, 1st -
口H(4i+(-;l...) Water treatment J
It is more effective to turn 11 two or more times.

The drawing shows a flow sheet of an embodiment of the present invention, and as is clear from a glance at the drawing, the present invention can be easily incorporated into a part of a series of manufacturing processes from ore refining to electrolytic treatment. In some cases, it can also be incorporated into the oxidation step (Fe-+Fe) in the series of manufacturing steps, thus improving the yield of manganese oxide and producing high-purity manganese dioxide. It can be manufactured relatively inexpensively.

As described above, the present invention uses a combination of the first step 4-Jl and the second step 4'11 to almost completely remove waxes and gypsum in the electrolytic cell accumulation, and finally recover solids. The remaining manganese oxide and electrolytic manganese dioxide, which is a product partially exfoliated from the electrode, can be separated, so relatively large electrolytic manganese dioxide products are sorted out and recovered as products, and other manganese oxides are recycled. Since it can be used repeatedly as manganese oxide suspended in the electrolytic solution, it is possible to improve the product yield and reduce the basic unit of manganese oxide that causes 1'IV1 turbidity, thereby reducing the manufacturing cost of electrolytic manganese dioxide. There is an effect of being able to do something.

Example Electrolysis of manganese dioxide by slurry method
After about 3 months of operation, the electrolysis was stopped, the accumulated material in the tank was taken out, and 1 kg was placed in a 20 g container. Further steam was blown into the mixture to heat it to 90° C. While stirring was continued for 15 minutes, the mixture took on an oily pattern and many bubbles were generated.

This was passed through Nunoche for 01, and the residue was returned to the original 2 (1
It was returned to the 0,0 container and the same treatment as above was repeated three times.

During this time, I picked up the fragmented product Den-W (manganese dioxide) in ^7I+1 with my fingers and recovered it as a product.

After completing the three hot water treatments, the residue is 1.000
After adding 500 n of water to this and stirring for 30 minutes, it was filtered using a Nunoche. The liquid temperature at this time is 23
It was ℃.

Return the aforementioned residue to the 1,000 stone container again and add 200 stones of water.
, e were added, stirred, and filtered through Nu7che to obtain the following residue.

[Brief explanation of drawings]

The drawing shows a flown-1 according to an embodiment of the present invention. patent applicant Japan Heavy Chemical Industry Co., Ltd. 1”: agent Rikichi Ichikawa

Claims (1)

[Claims] Electric j by suspending manganese oxide! In the method for producing IF4 manganese dioxide, 70
The first step is to add hot water at a temperature of ℃ or higher and recover the solid content by solid-liquid separation, and the second step is to add water to the solid content recovered in the first step, stir it, and then recover the solid content by solid-liquid separation. 2
A method for treating accumulated material in an electrolytic cell, characterized by comprising steps 4 and 1.