SU150828A1 - The method of obtaining crystalline potassium manganate - Google Patents

Description

Potassium manganate, an intermediate in the production of potassium permanganate, is obtained by fusing alkali with natural pyrolusite in an oxygen atmosphere according to the following scheme:

MpOz + 2 KOH K2Mp04 + NgO.

The process takes place at 250-450 °, the molar ratio between the alkali and pyrolusite in the initial reaction mixture is 2.5-3: 1 and the process duration is 32-36 hours. The degree of pyrolusite oxidation is 60-90Vo.

The proposed method for producing manganate is characterized in that for fusing take 1 part of pyrolusite and 5 parts of caustic potash, activation of pyrolusite and oxidation of it with oxygen of air is carried out at a pressure of 2 MPa in one apparatus-autoclave with a stirrer, followed by dissolving the melt and crystallizing it from the mother liquor . This method allows you to speed up and simplify the process.

Production of potassium manganate by the proposed method is carried out according to the following technology. The reactor, which is an autoclave type apparatus, receives molten alkali and ground pyrolusite from the Chiatura deposit. The load factor of the device is 40-50Vc. The temperature of the reaction mass support 200-220 °. The oxidation is carried out with gaseous oxygen with constant stirring of the mixture and a pressure in the reactor of 2 MPa. Oxygen enters the reactor as it is consumed. The oxidation process lasts 4 hours. At the end of the oxidation process, the potassium manganate melt in alkali is poured into alkaline water (40-100 g / l KOH) with constant mixing and a pulp is obtained, in which the alkali concentration is 500-600 with a potassium manganate concentration of 380-

L 1-50828- 2 -

420 g / l. The mixture is cooled to 20 °, while potassium manganate crystallizes. 3-5 g / l of K2MnO4 remain in the solution. After centrifugation, a potassium manganate paste is obtained, which contains (in Vo): 70-80 K2MnO4; 3-4 MpOg; 2-3 KOH, 0.5-1.0 KgSOz and an alkaline solution containing (g / l); 500-600 KOH, 3-5 K2MnO4 and 5-7 MpO-z.

The wood solution is evaporated and used for fusion with pyrolusite or, without prior evaporation, is processed into potash or other salts or materials.

Potassium manganate crystals are sent to electrolyte preparation.

The proposed method was tested in a laboratory setup with a capacity of 300 kg of manganate per day. At the same time, the following consumption norms were obtained in terms of 1 ton of permanganate: potassium hydroxide technical grade 1 0.525 g, manganese ore 0.8 tons, oxygen 0.25 tons, conditional fuel 1.5 tons.

Subject invention

The method of obtaining potassium manganate by melting pyrolusite with potassium hydroxide with an excess of the latter 25QVo in an oxygen atmosphere under pressure, characterized in that, in order to speed up the process and simplify it, for the alloying take 1 part of potassium hydroxide, pyrolusite activation and Its oxidation with air oxygen is carried out under a pressure of 2 MPa in one apparatus — an autoclave with a blender, followed by dissolving the melt and crystallizing it from the mother liquor.