SU1004263A1 - Process for producing potassium fluoride - Google Patents

Description

The invention relates to the production of potassium fluoride used for the production of fluoride salts.

A known method of producing potassium fluoride by the interaction of potassium silicofluoride with a solution of potassium carbonate by heating £ 1

The disadvantage of this method is the high content of impurities in the product.

The closest to the invention in technical essence and the achieved result is a method of producing potassium fluoride, including the interaction of hydrofluoric acid with a solution of potassium carbonate when heated to boiling, separating the precipitate of silicofluoride, potassium, followed by treatment at a boiling point of 10-30% solution of ^a P ^Bonate potassium, cooling and separating the silica precipitate from the solution. The Be · * ratio of hydrofluoric acid and potassium carbonate in the first stage is 1: 1.04 (2}.

The disadvantage of this method is the low product yield of 85%.

The purpose of the invention is to increase the yield of the product to 92.3-95.5%.

This goal is achieved in that according to the method of obtaining potassium fluoride, which consists in borrowing the action of hydrofluoric acid with a solution of potassium carbonate when heated, followed by the separation of the precipitate of silicon dioxide from the solution, and the weight ratio of hydrofluoric acid and potassium carbonate is maintained equal to 1: 3.0-3 , 3.

PRI me R 1. To obtain 348 g of potassium fluoride is heated to 50 ⁱⁿ C 15 1440 g of hydrofluorosilicic acid with a concentration of 12%, add 920 g of an 18% solution of potash, which corresponds to the weight ratio of H _x Sifb: K ^ SOU * 1: 1.04 and mix for 30 minutes. The precipitate was filtered off and 450 g of water was added thereto. The resulting suspension is heated to 50 * C, 2950 g of a 10% potash solution are added, the temperature is raised * 25 ru to 105 ° C, stirred for 2 hours, and cooled. The silica precipitate was separated by filtration and washed with 200 ml of water. Wash water is added to the stock solution. The concentration of the target product in solution® · solution is 10%. The fluorine yield is 85%.

PRI me R 2. To obtain 348 g of potassium fluoride is heated to 50 ° C.

1260 g of hydrofluoric acid with a concentration of 12% and adds 2550 g of an 18% potash solution, which corresponds to the weight ratio of H ^ SiFe: K ^ CO ^ 1: 3.03, heated to boiling, stirred for 2 hours and cooled. The silica precipitate was separated by filtration and washed with 200. ml of water. Wash water is added to the stock solution. The concentration of the target product in solution is 10%. Fluorine yield 95%.

Example 3. Potassium fluoride. Is obtained in the same manner as described in example 2, with the only difference that the amount of potash is 2778 g, which corresponds to the weight ratio:

: = 1: 3.30. The concentration of the target product in solution is 9.8%. The fluorine yield is 95.5%.

The table shows the dependence of the yield of potassium fluoride on the weight ratio of hydrofluoric acid and potassium carbonate.

Weight ratio 30 HoSlF ₆ :

: 1: 3.02 1: 3.01 1: 2.95

Fluorine yield,% 94.70 92.30 77.64

With a decrease in the weight ratio below 1: 3.0, a sharp decrease in the yield of the product occurs, and an increase in the ratio above 1: 3.3 is impractical due to an increase in the consumption of expensive potassium carbonate.

This method allows to increase the yield of the product from 85% to 92.3-95.5% and in addition, it allows to simplify the process by eliminating stage 10 of potassium silicofluoride and separating it by filtration.

Claims (2)

The thief is 10%. Fluorine yield 85% ,. PRI mme R 2. To obtain 348 fluoride, CAL is heated to 12/20 F / L acid and if) T 2550 g of an 18% potassium solution is added, which corresponds to the weight ratio: 1 g 3.03, heated to boiling, stirred for 2 h and cooled. The silica precipitate was filtered off and washed with 200. ml of water. Washed water is added to the basic solution. The concentration of the desired product in the solution is 10%. Fluorine yield 95%. EXAMPLE 3 Potassium fluoride is obtained in the same manner as described in Example 2 with the only difference that the amount of potash is 2778 g, which corresponds to the weight ratio H, 55iF: 1: 3.30. The concentration of the desired product in the solution is 9.8%. The yield of fluorine is 95.5%. The table shows the dependence of the yield of potassium fluoride on the weight ratio of hydrofluoric acid and potassium carbonate. Weight ratio: Is 3.02 Is 3.01 Is 2.9 S Yield pfto94, 70 92.30 77., b4 ra,% With a decrease in the weight ratio below 1: 3.0, there is a sharp decrease in the product yield, and an increase ratios above 1: 3.3 necessyubraeno due to increased consumption of expensive potassium carbonate. This method will increase the yield of the product from 85% to 92.3-95.5% and, in addition, allows the process to be improved by eliminating the stage of potassium silicofluoride and its separation by filtration. DETAILED DESCRIPTION OF THE INVENTION A method for producing potassium fluoride, which comprises reacting hydrofluoric acid with potassium carbonate solution when heated, followed by separation of a precipitate of silica from a solution, o. It is characterized by the fact that, in order to increase the yield of the product, the dispersion ratio of hydrofluoric acid and potassium carbonate is maintained at 1: 3.0-3.3. Sources of information taken into account in the examination 1. Chemistry and chemical technology, 5, 1, 1962, p. 115 2.Lzholovsky A.A. et al. Proceedings of the State Scientific Research Institute of Chemical Industry, vol. 2, 1955, p.5 (prototype).