SU858556A3 - Method of producing manganese dioxide - Google Patents

Description

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This invention relates to a process for producing manganese dioxide used in the production of dry cells.

A known method of producing manganese dioxide by decomposing a solution of manganese nitrate at a pressure of 3.5 atm under an oxygen overpressure for 15 minutes. 10

The disadvantage of this method is its complexity due to the need to use high pressure, as well as the low purity of the product obtained.

There is also known a method of producing manganese dioxide by precipitating impurities from a manganese solution and nitrate with a pI of 3.5-4.0, separating the precipitate, concentrating the solution of 20 manganese nitrate to a concentration of 55-70% without crystallization, decomposing manganese nitrate at 250-350 ° C under vacuum followed by a three-stage refinement of the obtained manganese dioxide-25 SI 2.

The disadvantage of this method is its complexity due to the need to purify manganese dioxide .30

The purpose of the invention is to simplify the process by eliminating the 9CLEANING operations.

Postav.1. The goal is achieved by the fact that, according to the method of producing manganese dioxide, the impurities are precipitated at a pH of 4.0-5.5 and a temperature of 70-105 s, and the decomposition of manganese nitrate is at a temperature of 135-14b C in the presence of 5 -25% manganese dioxide.

Distinctive features are the pH and the temperature at which the deposition of impurities leads, the decomposition temperature, the decomposition in the presence of manganese dioxide and its amount.

These differences make it possible to simplify the method for eliminating cleaning operations.

Claims (1)

At pH below 4.0, the content of impurities in the product increases, and at pH above 5.5 it is impractical to conduct the process. At temperatures below 70 ° C, incomplete removal of impurities occurs due to precipitation of impurities in an amorphous form, at temperatures above 105 ° C, boiling up of the solution is possible. At temperatures below, the decomposition rate of manganese nitrate is not high enough, and at temperatures above 4b C, the process is impractical. When the content of manganese dioxide during decomposition is less than 5%, the decomposition process is non-equilibrium and because of this, the product yield decreases, and when the content of two manganese oxides is more than 25%, the equipment is incrusted. Example. A solution of manganese nitrate is loaded into the tank, it is heated to pH and adjusted to 4.8 by adding manganese oxide. The precipitate of impurities is separated by filtration. The solution is concentrated to a content of MnCNOj) of 55% by weight, manganese dioxide is added to the resulting solution to keep it in suspension at 5% and 1,700 gallons of suspension per day with stirring, heated to and maintained at this temperature. From the reactor, 3,500 lb. day. After drying, the product contains weight. 63.0, Re 0.03, Av 0.007, Zn 0.0001, Cu 0.0015. DETAILED DESCRIPTION A method for producing manganese dioxide, which includes precipitating impurities from a manganese nitrate solution, separating the precipitate, concentrating the solution, and decomposing manganese nitrate when heated, followed by separating and drying manganese dioxide, in order to simplify the process by eliminating dioxide cleaning manganese, precipitation of impurities is carried out at a pH of 4.0-5.5, and the temperature VO-IOS C, and decomposition of manganese nitrate is carried out at 135-146 C in the presence of 5-25 wt.% manganese dioxide, Sources of information taken into account in examination 1, US Patent No. 2779659, class 23-145, published. 1957. 2, US Patent 3677700, CL.23-145, published. 1972.