SU470107A3 - The method of producing manganese dioxide - Google Patents

Description

(54) METHOD FOR PREPARING MANGANESE BIOXIDE

electrolyte. A slurry containing Mgg + ions and manganese dioxide is continuously discharged from cell 2 and fed to filter 3 to separate manganese dioxide. The filtered electrolyte contains L1p- + 5-15 g / l ions, ions and sulfuric acid. Most of the filtered electrolyte can be returned to the electrolyzer 2, and part of the electrolyte is heated in tank 4, the ions are hydrolyzed and the manganese dioxide formed is filtered on the filter 5, returned to the electrolyzer 2 where it is used as a seed, and the filtrate containing 0.1 - 0 , 7 g / l of ions, are directed to the heating tank 6.

The filtered electrolyte from filter 3 can directly flow into the heating tank 6. On the filter 3, manganese dioxide enters the heating tank 6 and is heated there in the electrolyte filtered on the filter 3 or in a mixture of this electrolyte and the filtrate from the filter 5.

Manganese dioxide is subjected to further processing — filtration on filter 7, neutralization and washing, drying, before being converted into the desired product. The filtrate from filter 7 contains free sulfuric acid, miZ + ions in low concentration, it is returned to tank 1 for leaching manganese from raw materials.

The practical implementation of the proposed method is illustrated by the following examples.

Example 1

Electrolysis.

4L electrolyzer. Electrodes: the anode is pure lead dioxide, obtained by electrolytic deposition, the cathode is graphite. The distance between the electrodes is 9 mm. The composition of the electrolyte: the concentration of free sulfuric acid 400 g / l, the concentration of ions L1ts2 + - 20 g / l. Temperature - 37 ° C. Current density 45 a / dm. The average voltage on the electrolyzer is 3.7 b. Raw materials: manganese sulphate solution containing 120 g / l Mn2 +. The amount of the loaded raw material is 200 ml / hour, the loading is continuous.

Heating after electrolysis.

Heating temperature 95 ° C. Duration of heating is 2 hours. The electrolyte used for heating contains 400 g / l sulfuric acid, 20 g / l and 0.3 g / l Mp3 +.

Current efficiency and composition of manganese dioxide.

The current efficiency is 76% for 6 hours of electrolysis.

The product contains: total manganese — 58.0%, manganese dioxide — 87.9%, bound water — 7, 0%, Pb —0.009%.

The structure of the crystals y - MnO2.

PRI me R 2.

The electrolyzer, the electrodes and the distance between them are the same as in Example 1.

The composition of the electrolyte: the concentration of free sulfuric acid 500 g / l, concentration

Mn2 + ions - 16 g / l. Temperature 45 ° C. Current density 60 a / dm. The average voltage on the electrolyzer is 4.3 b. Raw materials: a solution of manganese sulphate, containing PO g / l of ions, obtained by leaching manganese carbonate. Quantity of the loaded raw materials: 240 ml / hour, loading is continuous. Heating after electrolysis. Heating temperature 70 ° C. Duration of heating is 3 hours. The electrolyte used for heating contains 500 g / l of sulfuric acid, 16 g / l of Alc2 + and 9.5 g / l.

Current efficiency and composition of manganese dioxide. The current efficiency of 71.2% per 24 hours electrolysis.

Product: total manganese - 58.0%, manganese dioxide - 86.4%, bound water - 9.8%.

The structure of the crystals y - MnOg and a small amount of a - MnOg. Froze Electrolysis.

The cell, as in example 1. Electrodes: the anode and the cathode of lead. The distance between the electrodes is 14 mm.

The composition of the electrolyte: the same as in example 1. Temperature 40 ° C. Current density 50 a / dm. The average cell voltage is 3.9 volts. Raw materials: manganese solution containing 100 g / l, obtained by leaching manganese oxide (MpO). The amount of raw material loaded 210 ml / hour, loading is continuous.

Heating after electrolysis. Heating temperature 80 ° C. The duration of heating is 1.6 hours. The electrolyte for heating is the same as in example 1.

Current efficiency and composition of manganese dioxide.

The current efficiency is 73.5% for 48 hours of electrolysis.

Product: total manganese — 58.3%, manganese dioxide — 87.0%, bound water — 7.5%.

The structure of the crystals y - MpOa and a small amount of a - MpOg.

Manganese dioxide, obtained by the proposed method, has a closed value of more than 1 in 15-20% more than in products obtained by known methods, as well as high depolarizing properties.

Subject invention

The method of obtaining manganese dioxide by electrolysis of sulfate solutions of divalent manganese containing free sulfuric acid, followed by separation of manganese dioxide from the electrolyte by filtration, washing and total precipitate, characterized in that, in order to intensify the process and improve the quality of the manganese dioxide in solution, from 10 to 40 g / l of free sulfuric acid is maintained from 400 to 600 g / l, electrolysis is carried out at a temperature of 30-50 ° C, at a current density of 30-75 a / dm.

2. A method according to claim 1, characterized in that, after filtration, the manganese dioxide is treated at a temperature of 50-100 ° C for 0.5-4 hours with stirring in the filtered electrolyte, after which the solution is subjected to repeated filtration.

3. Method according to paragraphs. I and 2, characterized in that the manganese dioxide is treated in a solution obtained from a portion of the filtered electrolyte after separation from it when heated manganese dioxide, which is returned to the electrolysis as a seed. 4. The method according to paragraphs. 1, 2 and 3, characterized in that manganese dioxane is treated in a mixture of a portion of a filtered electrolyte with a solution obtained from another portion of a filtered electrolyte after separation from it by heating manganese dioxide, which is returned to electrolysis as a seed.