SU582331A1 - Electrochemical method of obtaining silver oxide - Google Patents

Description

one

The invention relates to the field of electrochemical production of silver oxide.

A known chemical method for producing silver oxide is by mixing a pure solution of silver nitrate with alkali. The precipitation is washed with water, freed from carbon dioxide, and dried at a temperature of 85-88 ° C. 1. The method requires pure starting reagents.

The closest technical solution to the invention is an electrochemical method for producing silver oxide, which consists in the electrochemical dissolution of metallic silver in a nitrate-silk electrolyte in a diaphragm electrolytic cell at a current density above 0.15 A / cm and in a rate of 60 ° C. 2. This method is difficult, namely, frequent replacement and regeneration of the diaphragms is necessary, due to the fact that on the membranes in the electrolysis process there occurs a partial reduction of silver cations to a metallic silver core It is associated with a sharp decrease in the electrical conductivity of the membranes, the yield of silver oxide and the contamination of the oxide with metallic silver.

The purpose of the invention is to simplify the method.

This is achieved by the fact that the process of electrochemical dissolution of metallic, silver is carried out in a diaphragm-free flow electrolyzer in an appetizer-alkaline electrolyte at a current density of 0.45-0.50 a / cm and the same temperature of 25-50 ° C. The electrolyte used is a solution of potassium hydroxide and potassium acetate in a ratio of 1: 6.8-

8.5 wt. h

The electrolyte is circulated in the direction from the cathode to the anode at a rate of 40-60 l / h. The yield of silver oxide by current is 92.0--95.0% with the content of the basic substance not lower than 99.9%, determined by

chemical analysis methods. The drawing is a technological scheme for the production of silver oxide.

Electrochemical dissolution of edetallic silver is carried out in the electrolyzer 1. The electrolyzer is a tube with two electrodes: a silver anode and a cathode of silver or stainless steel. The cell is equipped with a cooling jacket.

Formed with silver oxide under the action of a circulating electrolyte enters the vacuum filter 2 from a porous fluoroplast, where it is separated from the electrolyte. Further, the electrolyte is supplied to the auxiliary electrolyzer 4 by means of a bellows pump 3, where the dissolved silver oxide is removed from the electrolyte. Electrolyte purification is the iboc reduction of oxide on a stainless cathode.

steel or titanium to metal grains that precipitate out of solution. Then, the purified electrolyte passes through the filter 5 and returns to the electrolyzer 1 by pump 6.

Auxiliary electrolysis cell 4 is a cylindrical tank with a cooling jacket. The cathode is a cylinder made of stainless steel or titanium, the anode is platinum or platinized titanium.

Example. Electrochemical dissolution of metallic silver is carried out in an electrolyte containing 2.0 kg of potassium acetate and 0.3 kg of potassium hydroxide in 1 liter at a current density of 0.45 A / cm and a temperature of 38 ° C. Metallic silver is used as the cathode material. The distance between the electrodes is 100 mm. The flow rate of the electrolyte is 4600 l / h. After electrolysis, the silver oxide is washed with water and dried. The yield of the finished product is 179 g / dm per hour (yield

For current use: -95.0%). € The content of the main substance is more than 99.91%.

Claims (2)

1. Karin Yu. 3. Pure chemical reagents. M.-L., 1947, p. 488. 2. The patent of Germany No. 1168401, cl. 12p 5/00, 04.23.64. VO /