CN116161679A - A kind of method for continuously synthesizing sodium fluoride - Google Patents

Abstract

The present invention provides a method for continuously synthesizing sodium fluoride, comprising the following steps: the alkali A in the first cooling tube pass of the low-temperature reaction module 1 passed into the continuous flow reactor through the first metering pump is cooled to the first set temperature 40 ‑50°C; through the second metering pump, the hydrofluoric acid B in the second cooling tube of the low temperature reaction module of the continuous flow reactor is cooled to the first set temperature of 40‑50°C; the two streams are reduced to the first set temperature The materials with a temperature of 40-50°C are combined, and in the main process of the low-temperature reaction module, after the neutralization reaction at the first set temperature of 40-50°C for 2-5 minutes, they pass through the pipeline of the high-temperature reaction module of the continuous flow reactor ;React at the second set temperature of 80-95°C for 1-2min, the reaction product enters the filter through the pipeline, then passes through the concentrator, passes through the crystallizer, passes through the scrubber and the dryer, and obtains the sodium fluoride product C, shortening the reaction time .

Description

A kind of method for continuously synthesizing sodium fluoride

technical field

The invention relates to the technical field of chemical metallurgy, in particular to a method for continuously synthesizing sodium fluoride.

Background technique

Sodium fluoride is a colorless crystal or white powder, soluble in water, slightly soluble in alcohol, commonly used as wood preservative, hydrogen fluoride adsorbent, agricultural fungicide, insecticide, water treatment agent, smelting and refining protective agent, steel Fluxes for cleaning fluids and other metals, leather and skin treatment agents for leather industry, anti-wear additives for brake pads, and anti-corrosion additives for concrete. The synthesis of sodium fluoride often adopts aqueous phase synthesis methods, such as ammonium fluoride neutralization method, hydrofluoric acid neutralization sodium carbonate method, and sodium fluorosilicate soda ash method. The operating process of the existing hydrofluoric acid neutralization method is: add 40% hydrofluoric acid to the lead reaction kettle, slowly add sodium carbonate solution for neutralization, until the pH value of the reaction solution is 8-9, and the carbon dioxide gas stops escaping stop responding. Since the hydrofluoric acid contains fluosilicic acid impurities, after the synthesis reaction is completed, the synthesis solution must be heated at 90-95°C for 1 hour to completely decompose the sodium fluosilicate. The heated solution was left to stand for 1 hour, and the clear liquid was concentrated and cooled to precipitate sodium fluoride crystals, and then centrifuged, dried, and pulverized to obtain the product sodium fluoride. The existing method has the disadvantages of long operation time and low efficiency.

Contents of the invention

The purpose of the invention is to solve the problems of long operation time and low efficiency in the existing method, and propose a method for continuously synthesizing sodium fluoride.

A method for continuously synthesizing sodium fluoride, comprising the steps of: cooling the base A in the first cooling tube of the low temperature reaction module 1 of the continuous flow reactor through the first metering pump to the first set temperature of 40-50°C The hydrofluoric acid B of the second cooling tube of the low-temperature reaction module passed into the continuous flow reactor by the second metering pump is cooled to the first set temperature 40-50 ° C; the two streams are dropped to the first set temperature 40- The materials at 50°C are combined, in the main process of the low-temperature reaction module, after neutralization reaction at the first set temperature of 40-50°C for 2-5 minutes, they pass through the tube pass of the high-temperature reaction module of the continuous flow reactor through the pipeline; 2. Set the temperature at 80-95°C to react for 1-2 minutes. The reaction product enters the filter through the pipeline, then passes through the concentrator, crystallizer, scrubber and dryer to obtain sodium fluoride product C.

As a further improvement of the present invention, the base A is one of the aqueous solutions of sodium hydroxide, sodium carbonate, and sodium bicarbonate.

As a further improvement of the present invention, the hydrofluoric acid B is an aqueous hydrogen fluoride solution with a mass fraction of 40%-50%.

Beneficial effects of the present invention:

The method of the present invention converts hydrofluoric acid and alkali into sodium fluoride and has a short reaction time. The method of the present invention adopts a continuous flow reactor. Since the continuous flow reactor has a large heat exchange area and significant pressure drop, the reaction can be made It has high heat exchange efficiency and mass transfer efficiency, and does not need to pre-mix the reaction materials, and the reaction is easier to control. The method of the invention can control the reaction conditions and increase the safety of the reaction, and has the advantages of short reaction cycle, high conversion efficiency and the like.

Description of drawings

Fig. 1 is the reaction flow chart of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Example 1

A method for continuously synthesizing sodium fluoride (the device used is shown in Figure 1), comprising the following steps: A (hydrogen sodium oxide aqueous solution) to the first set temperature of 40°C; through the second metering pump 10, the hydrofluoric acid B (mass fraction is 40% Hydrogen fluoride aqueous solution) is cooled to the first set temperature of 40°C; the two streams of materials dropped to the first set temperature of 40°C are combined and neutralized at the first set temperature of 40°C in the main process 13 of the low temperature reaction module 1 After reacting for 5 minutes, pass through the tube side of the high-temperature reaction module 2 of the continuous flow reactor 8 through the pipeline; react at the second set temperature of 80°C for 2 minutes, and the reaction product enters the filter 3 through the pipeline, then passes through the concentrator 4, and passes through the crystallizer 5 , through the scrubber 6 and the dryer 7, sodium fluoride product C is obtained. After determination, the yield of sodium fluoride was 98%, and the purity was 99%.

Example 2

A method for continuously synthesizing sodium fluoride (the device used is shown in Fig. 1), comprising the following steps: the base A ( saturated sodium carbonate aqueous solution) to the first set temperature of 50°C; the hydrofluoric acid B (mass fraction of 50 % hydrogen fluoride aqueous solution) to the first set temperature of 50°C; the two streams of materials dropped to the first set temperature of 50°C are combined, and in the main process 13 of the low temperature reaction module 1, at the first set temperature of 50°C After reacting for 2 minutes, pass through the tube pass of the high-temperature reaction module 2 of the continuous flow reactor 8 through the pipeline; react at the second set temperature of 95° C. for 1 minute, and the reaction product enters the filter 3 through the pipeline, then passes through the concentrator 4, and passes through the crystallizer 5. After going through the scrubber 6 and the dryer 7, the sodium fluoride product C is obtained. After determination, the yield of sodium fluoride was 97%, and the purity was 99%.

Example 3

A method for continuously synthesizing sodium fluoride (the device used is shown in Fig. 1), comprising the following steps: the base A ( sodium bicarbonate saturated aqueous solution) is cooled to the first set temperature of 45°C; the hydrofluoric acid B (mass fraction of 45% hydrogen fluoride aqueous solution) is cooled to the first set temperature of 45°C; the two streams of materials dropped to the first set temperature of 45°C are combined, and in the main process 13 of the low temperature reaction module 1, at the first set temperature of 45°C After 2 minutes of neutralization reaction, pass through the pipeline through the tube side of the high-temperature reaction module 2 of the continuous flow reactor 8; react at the second set temperature of 90°C for 1 minute, and the reaction product enters the filter 3 through the pipeline, then passes through the concentrator 4, and undergoes crystallization Device 5, through scrubber 6 and dryer 7, sodium fluoride product C is obtained. After determination, the yield of sodium fluoride was 99%, and the purity was 99%. Continuous flow reactors are commercially available, such as G1, G2, G3 and G4 continuous flow reactors from Corning, USA.

Claims (3)

1. A method for continuously synthesizing sodium fluoride, comprising the steps of: passing through the first metering pump (9) into the first cooling tube (11) of the low temperature reaction module (1) of the continuous flow reactor (8) The base A is cooled to the first set temperature of 40-50°C; the hydrogen fluorine is passed into the second cooling tube (12) of the low temperature reaction module (1) of the continuous flow reactor (8) through the second metering pump (10) The temperature of acid B is lowered to the first set temperature of 40-50°C; the two streams of materials dropped to the first set temperature of 40-50°C are combined, and in the main process (13) of the low-temperature reaction module (1), in the first set After the neutralization reaction at a fixed temperature of 40-50°C for 2-5min, pass through the pipeline through the tube side of the high-temperature reaction module (2) of the continuous flow reactor (8); react at the second set temperature of 80-95°C for 1-2min, The reaction product enters the filter (3) through the pipeline, then passes through the concentrator (4), passes through the crystallizer (5), passes through the scrubber (6) and the dryer (7), and obtains sodium fluoride product C. 2. a kind of method for continuously synthesizing sodium fluoride according to claim 1, is characterized in that: described alkali A is the one in the aqueous solution of sodium hydroxide, sodium carbonate, sodium bicarbonate. 3. a kind of method for continuously synthesizing sodium fluoride according to claim 1, is characterized in that: described hydrofluoric acid B is the hydrogen fluoride aqueous solution that mass fraction is 40%-50%.

Images