WO2023088016A1 - Production method for sodium bromide - Google Patents

Abstract

Disclosed in the present invention is a production method for sodium bromide. Bromine-containing brine is directly used as a raw material, so that the price is low; three absorption towers that are connected to each other are used for absorbing blown-out bromine, so that bromine can be more thoroughly absorbed, the waste of the raw material is avoided, and it is also prevented that unabsorbed bromine overflows into air to pollute the environment; a fan providing a power source for bromine-containing air entering the absorption towers also provides power for bromine blowing of an oxidized liquid, and thus, the whole cyclic operation is closed, bromine cannot overflow into the external environment, it is also ensured that bromine can be circularly absorbed, the yield rate of a product is improved, impurities such as sodium bromate cannot be produced in the whole reaction process, technological treatment is simpler, and the process period is shortened.

Description

A kind of production method of sodium bromide

Solemnly declare:

This invention claims priority from the following patent applications:

The application date is November 22, 2021, the application number is 202111387937.5, and the Chinese invention patent application titled "a production method of sodium bromide".

technical field

The invention relates to the technical field of sodium bromide production, in particular to a production method of sodium bromide.

Background technique

Sodium bromide is an inorganic compound, which can be used in photosensitive industry, perfume industry, printing and dyeing industry, etc. It can also be used in trace determination of cadmium, manufacture of bromide, inorganic and organic synthesis, photographic paper plate, etc. At present, the production of sodium bromide is generally produced by neutralizing hydrobromic acid and sodium hydroxide, or using sodium hydroxide to absorb bromine. Both of the above two methods produce impurity sodium bromate, which needs to be reduced by carbon powder Removal, this has increased process difficulty greatly, has also prolonged process cycle, has improved cost, and the sodium bromate that is difficult to handle and remove has also reduced the quality of sodium bromide product simultaneously.

Contents of the invention

The technical problem to be solved by the present invention is: aiming at the deficiencies in the prior art, provide a production method of sodium bromide, extract bromine from brine, the cost of raw materials is low, the reaction cycle is short, and no sodium bromate will be produced in the reaction at the same time and other impurities, the quality of sodium bromide products is relatively high.

In order to solve the problems of the technologies described above, the technical solution of the present invention is:

A kind of production method of sodium bromide, comprises the following steps:

A: Chlorine and bromine-containing brine are mixed in a static mixer to form an oxidizing solution;

B: The oxidizing solution is sprayed and blown out by air in the blowing tower to obtain bromine-containing air and blown waste brine;

C: Sodium formate solution is poured into the primary absorption tower, secondary absorption tower and tertiary absorption tower as the absorption liquid, and bromine-containing air is discharged from the top of the blowing tower and then enters the connected primary absorption tower and secondary absorption tower and three-stage absorption tower, the bromine in the bromine-containing air is sequentially absorbed by the absorption liquid in the absorption towers at all levels to form a mixed solution of sodium bromide and hydrobromic acid, and the absorption liquid in the three-stage absorption tower overflows to the second stage through the pipeline The first-level absorption tower, the absorption liquid in the second-level absorption tower overflows to the first-level absorption tower through the pipeline;

D: The sodium hydroxide solution is passed into the primary absorption tower to adjust the pH of the absorption liquid in the primary absorption tower, and then the absorption liquid in the primary absorption tower is discharged to the absorption liquid storage tank through overflow, and the absorption liquid is stored The absorption liquid in the tank is poured into the refining kettle at a certain flow rate, and ammonia water is passed into the refining kettle to adjust the color of the absorption liquid in the refining kettle, and then filter to obtain the supernatant;

E: The supernatant is poured into the double-effect evaporator through the feed pump, and in the double-effect evaporator, it is heated by steam and concentrated until sodium bromide crystals are precipitated. After being centrifuged in a centrifuge, solid sodium bromide is obtained. The centrifuged mother liquor is Liquid Sodium Bromide.

Preferably, the three-stage absorption tower is connected to the sodium formate preparation tank through an absorbent feed pump.

Preferably, the concentration of the sodium formate solution in the sodium formate preparation tank is 20-25%.

Preferably, the first-level absorption tower, the second-level absorption tower and the third-level absorption tower are all provided with a self-circulating spray pump, and the flow rate of the bromine-containing air entering the first-level absorption tower is the same as that of the first-level absorption tower, the second-level absorption tower and the third-level absorption tower. The gas-liquid flow ratio of the self-circulating spray flow of the absorption tower is 50:1-70:1.

Preferably, sodium hydroxide is added to the blown brine in step B, and the pH is adjusted to 7.0-8.0 for salt drying or adjusted to the value of the original bromine-containing brine before backfilling.

Preferably, the chlorine distribution ratio of chlorine in step A is controlled to be 103%-105%.

Preferably, in step B, the gas-liquid flow ratio of the air entering the blowing tower to the oxidizing liquid sprayed in the blowing tower is 150:1-200:1.

Preferably, sodium hydroxide is added in step D to adjust the pH of the absorption solution to 7-8.

Preferably, when the supernatant in step E is concentrated in the double-effect evaporator, the temperature of the feed liquid in the first-effect evaporator is controlled at 78-82°C, and the temperature of the feed liquid in the second-effect evaporator is controlled at 68-72°C.

Preferably, after the bromine-containing air absorbs bromine in step C, the remaining air is discharged from the top of the three-stage absorption tower and is pumped by a fan to the bottom of the blowing tower as a power source for blowing bromine to the oxidizing liquid.

Production principle of the present invention is:

Oxidation of brine:

Chlorine is added to the bromine-containing brine for oxidation to obtain an oxidized solution. The reaction formula is:

2Br ^- +Cl ₂ —2Cl ^- +Br ₂ ①

Sodium formate absorbs bromine:

Utilize sodium formate solution to absorb bromine to generate the mixed solution of sodium bromide and hydrobromic acid, and concrete reaction formula is:

HCOONa+Br ₂ ＝NaBr+HBr+CO ₂ ↑ ②

Hydrobromic acid neutralization:

Utilize sodium hydroxide to react with hydrobromic acid produced by ② to generate sodium bromide, and the equation is:

NaOH+HBr—NaBr+H ₂ O ③

After finishing the above reaction, the reaction formula is:

HCOONa+Br ₂ +NaOH—2NaBr+CO ₂ ↑+H ₂ O ④

Brief description of the process flow:

1. The process of brine: the brine in the brine pool is transported to the brine pipeline through the brine pump, and mixed with chlorine gas in the brine static mixer to form an oxidation liquid. The top is sprayed down, and it is in countercurrent contact with the air blown in from the bottom of the blowing tower, the bromine in the oxidizing liquid is blown out, and the oxidizing liquid becomes blown waste brine, which is discharged from the bottom of the bottom of the blowing tower, and blown waste brine discharged from the blowing tower Add caustic soda dropwise to adjust the pH value of the waste brine to the required value, and then transport it to the next process.

2. The process of bromine: the bromine in the oxidizing liquid is blown out, and the bromine-containing air is discharged from the top of the blowing tower, and the bromine-containing air enters the primary absorption tower. In the primary absorption tower, the bromine in the air is absorbed by sodium formate. Absorption produces a mixed solution of sodium bromide and hydrobromic acid, and the unabsorbed bromine enters the secondary bromine absorption tower with the air, and then enters the third-stage bromine absorption tower until the bromine is completely absorbed.

3. Sodium formate absorption liquid process: a certain concentration of sodium formate solution is injected into the third-stage absorption tower at a certain flow rate as an absorbent, and the sodium formate absorption liquid is circulated and sprayed through a self-circulating spray pump to absorb the incompletely absorbed bromine in the third-stage absorption tower After the prime, it overflows to the secondary absorption tower by the potential difference, and performs the same operation in the secondary absorption tower, and the absorption liquid overflows to the primary absorption tower, and the control index of the primary absorption liquid meets the production requirements, and reaches the end point The absorbing liquid overflows into the absorbing liquid storage tank.

4. Refining process of absorbing liquid: the absorbing liquid in the absorbing liquid storage tank is pumped into the refined 釡 with the absorbing liquid pump, and a certain amount of ammonia water is added to the refined 釡, reacting with the free bromine in the solution to remove the free bromine and adjust the chromaticity Then filter the supernatant.

5. Concentration and crystallization process of sodium bromide solution: the supernatant is pumped into the double-effect evaporator through the feed pump of the double-effect evaporator, and in the double-effect evaporator, it is heated by steam, and the solid-liquid ratio of the liquid in the second-effect evaporator When it reaches 3:1, the material in the second-effect evaporator is transferred to the centrifuge, and at the same time, the material in the first-effect evaporator is transferred to the second-effect evaporator to replenish its liquid level. The sodium bromide solution is concentrated and passed through the centrifuge Solid sodium bromide is obtained by centrifugation, and the centrifuged mother liquor is sold as a liquid product.

Owing to adopted above-mentioned technical scheme, the beneficial effect of the present invention is:

1. Directly use bromine-containing brine as raw material, and the price is low.

2. Three connected absorption towers are used to absorb the blown bromine, so that the bromine can be absorbed more thoroughly, avoiding the waste of raw materials, and at the same time prevent the unabsorbed bromine from overflowing into the air and polluting the environment .

3. The fan that provides the power source for the bromine-containing air to enter the absorption tower also provides power for the bromine blowing of the oxidizing solution. The entire cycle is operated in a closed manner, so that the bromine will not overflow into the external environment, and at the same time ensure that the bromine can be recycled and absorbed. Increased product yield.

4. There will be no impurities such as sodium bromate in the product, the process is simpler and the process cycle is shortened.

5. Sodium formate is used as the absorbent, and sodium bromide and hydrobromic acid are generated after the reaction, and sodium bromate that is difficult to remove will not be produced, and the purity of the product is higher.

Description of drawings

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

Fig. 1 is the process flow diagram of the embodiment of the present invention.

Detailed ways

The present invention will be further described below in conjunction with FIG. 1 and various embodiments.

Example 1

A kind of production method of sodium bromide, comprises the following steps:

A: Use chlorine gas to oxidize bromine-containing brine to generate oxidizing liquid, and the chlorine distribution rate of chlorine gas is controlled to 103%;

B: The oxidizing solution is sprayed in from the top of the blowing tower through a spraying device, and is in countercurrent contact with the air blown in from the bottom of the blowing tower, the bromine in the oxidizing solution is blown out and mixed with air to form bromine-containing air, and the bromine is blown out The final oxidizing liquid becomes the blowing waste brine and is discharged from the bottom of the bottom of the blowing tower;

C: Bromine-containing air is discharged from the top of the blowing tower and enters the primary absorption tower. In the primary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid, which is not absorbed. The absorbed bromine enters the secondary absorption tower with the air. In the secondary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid. Enter the third-stage absorption tower until the bromine is completely absorbed, and the air after absorbing the bromine is discharged from the top of the third-stage absorption tower and pumped by the fan to the bottom of the blowing tower as the power source for blowing bromine to the oxidizing liquid;

D: Pass sodium hydroxide solution into the primary absorption tower to adjust the pH of the absorption liquid in the primary absorption tower to 7~8, then the absorption liquid in the primary absorption tower is discharged to the absorption liquid storage tank through overflow, The absorption liquid in the absorption liquid storage tank is poured into the refining kettle at a certain flow rate, and ammonia water is passed into the refining kettle to adjust the color of the absorption liquid in the refining kettle, and then filter to obtain the supernatant;

E: The supernatant is poured into the double-effect evaporator through the feed pump, and in the double-effect evaporator, it is heated by steam and concentrated until sodium bromide crystals are precipitated. After being centrifuged in a centrifuge, solid sodium bromide is obtained. The centrifuged mother liquor is Liquid Sodium Bromide.

The third-stage absorption tower is connected to the sodium formate preparation tank through the absorbent liquid supply pump, the absorption liquid in the third-stage absorption tower overflows to the second-stage absorption tower through the pipeline, and the absorption liquid in the second-stage absorption tower overflows to the first-stage absorption through the pipeline tower.

The concentration of sodium formate solution in the described sodium formate preparation tank is 20%.

The first-level absorption tower, the second-level absorption tower and the third-level absorption tower are all equipped with self-circulating spray pumps, and the flow rate of the bromine-containing air entering the first-level absorption tower is the same as that of the first-level absorption tower, the second-level absorption tower and the third-level absorption tower. The gas-liquid flow ratio of the self-circulating spray flow is 50:1.

Sodium hydroxide is added to the waste blowing brine in step B, and the pH is adjusted to 7.0-8.0 for drying salt or adjusting the pH to the value of the original bromine-containing brine before backfilling.

In step B, the gas-liquid flow ratio of the air entering the blowing tower to the oxidizing liquid sprayed in the blowing tower is 150:1.

When the supernatant in step E is concentrated in the double-effect evaporator, the temperature of the feed liquid in the first-effect evaporator is controlled at 78°C, the temperature of the feed liquid in the second-effect evaporator is controlled at 68°C, and the feed liquid in the second-effect evaporator is When the solid-liquid ratio reaches 3:1, the material in the second-effect evaporator is transferred to the centrifuge, and at the same time, the material in the first-effect evaporator is transferred to the second-effect evaporator to replenish its liquid level.

Example 2

A kind of production method of sodium bromide, comprises the following steps:

A: Use chlorine gas to oxidize bromine-containing brine to generate oxidizing liquid, and the chlorine distribution rate of chlorine gas is controlled at 105%;

B: The oxidizing solution is sprayed in from the top of the blowing tower through a spraying device, and is in countercurrent contact with the air blown in from the bottom of the blowing tower, the bromine in the oxidizing solution is blown out and mixed with air to form bromine-containing air, and the bromine is blown out The final oxidizing liquid becomes the blowing waste brine and is discharged from the bottom of the bottom of the blowing tower;

C: Bromine-containing air is discharged from the top of the blowing tower and enters the primary absorption tower. In the primary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid, which is not absorbed. The absorbed bromine enters the secondary absorption tower with the air. In the secondary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid. Enter the third-stage absorption tower until the bromine is completely absorbed, and the air after absorbing the bromine is discharged from the top of the third-stage absorption tower and pumped by the fan to the bottom of the blowing tower as the power source for blowing bromine to the oxidizing liquid;

D: Pass sodium hydroxide solution into the primary absorption tower to adjust the pH of the absorption liquid in the primary absorption tower to 7~8, then the absorption liquid in the primary absorption tower is discharged to the absorption liquid storage tank through overflow, The absorption liquid in the absorption liquid storage tank is poured into the refining kettle at a certain flow rate, and ammonia water is passed into the refining kettle to adjust the color of the absorption liquid in the refining kettle, and then filter to obtain the supernatant;

E: The supernatant is poured into the double-effect evaporator through the feed pump, and in the double-effect evaporator, it is heated by steam and concentrated until sodium bromide crystals are precipitated. After being centrifuged in a centrifuge, solid sodium bromide is obtained. The centrifuged mother liquor is Liquid Sodium Bromide.

The third-stage absorption tower is connected to the sodium formate preparation tank through the absorbent liquid supply pump, the absorption liquid in the third-stage absorption tower overflows to the second-stage absorption tower through the pipeline, and the absorption liquid in the second-stage absorption tower overflows to the first-stage absorption through the pipeline tower.

The concentration of sodium formate solution in the described sodium formate preparation tank is 22%.

The first-level absorption tower, the second-level absorption tower and the third-level absorption tower are all equipped with self-circulating spray pumps, and the flow rate of the bromine-containing air entering the first-level absorption tower is the same as that of the first-level absorption tower, the second-level absorption tower and the third-level absorption tower. The gas-liquid flow ratio of the self-circulating spray flow is 50:1.

Sodium hydroxide is added to the blown brine in step B, and the pH is adjusted to 7.0-8.0 for drying salt or adjusting the pH to the value of the original bromine-containing brine before backfilling.

In step B, the gas-liquid flow ratio of the air entering the blowing tower to the oxidizing liquid sprayed in the blowing tower is 150:1.

When the supernatant in step E is concentrated in the double-effect evaporator, the temperature of the feed liquid in the first-effect evaporator is controlled at 78°C, the temperature of the feed liquid in the second-effect evaporator is controlled at 68°C, and the feed liquid in the second-effect evaporator is When the solid-liquid ratio reaches 3:1, the material in the second-effect evaporator is transferred to the centrifuge, and at the same time, the material in the first-effect evaporator is transferred to the second-effect evaporator to replenish its liquid level.

Example 3

A kind of production method of sodium bromide, comprises the following steps:

A: Use chlorine gas to oxidize bromine-containing brine to generate oxidizing liquid, and the chlorine distribution rate of chlorine gas is controlled at 105%;

B: The oxidizing solution is sprayed in from the top of the blowing tower through a spraying device, and is in countercurrent contact with the air blown in from the bottom of the blowing tower, the bromine in the oxidizing solution is blown out and mixed with air to form bromine-containing air, and the bromine is blown out The final oxidizing liquid becomes the blowing waste brine and is discharged from the bottom of the bottom of the blowing tower;

C: Bromine-containing air is discharged from the top of the blowing tower and enters the primary absorption tower. In the primary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid, which is not absorbed. The absorbed bromine enters the secondary absorption tower with the air. In the secondary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid. Enter the third-stage absorption tower until the bromine is completely absorbed, and the air after absorbing the bromine is discharged from the top of the third-stage absorption tower and pumped by the fan to the bottom of the blowing tower as the power source for blowing bromine to the oxidizing liquid;

D: Pass sodium hydroxide solution into the primary absorption tower to adjust the pH of the absorption liquid in the primary absorption tower to 7~8, then the absorption liquid in the primary absorption tower is discharged to the absorption liquid storage tank through overflow, The absorption liquid in the absorption liquid storage tank is poured into the refining kettle at a certain flow rate, and ammonia water is passed into the refining kettle to adjust the color of the absorption liquid in the refining kettle, and then filter to obtain the supernatant;

E: The supernatant is poured into the double-effect evaporator through the feed pump, and in the double-effect evaporator, it is heated by steam and concentrated until sodium bromide crystals are precipitated. After being centrifuged in a centrifuge, solid sodium bromide is obtained. The centrifuged mother liquor is Liquid Sodium Bromide.

The third-stage absorption tower is connected to the sodium formate preparation tank through the absorbent liquid supply pump, the absorption liquid in the third-stage absorption tower overflows to the second-stage absorption tower through the pipeline, and the absorption liquid in the second-stage absorption tower overflows to the first-stage absorption through the pipeline tower.

The concentration of sodium formate solution in the described sodium formate preparation tank is 25%.

The first-level absorption tower, the second-level absorption tower and the third-level absorption tower are all equipped with self-circulating spray pumps, and the flow rate of the bromine-containing air entering the first-level absorption tower is the same as that of the first-level absorption tower, the second-level absorption tower and the third-level absorption tower. The gas-liquid flow ratio of the self-circulating spray flow is 50:1.

Sodium hydroxide is added to the waste blowing brine in step B, and the pH is adjusted to 7.0-8.0 for drying salt or adjusting the pH to the value of the original bromine-containing brine before backfilling.

In step B, the gas-liquid flow ratio of the air entering the blowing tower to the oxidizing liquid sprayed in the blowing tower is 150:1.

When the supernatant in step E is concentrated in the double-effect evaporator, the temperature of the feed liquid in the first-effect evaporator is controlled at 78°C, the temperature of the feed liquid in the second-effect evaporator is controlled at 68°C, and the feed liquid in the second-effect evaporator is When the solid-liquid ratio reaches 3:1, the material in the second-effect evaporator is transferred to the centrifuge, and at the same time, the material in the first-effect evaporator is transferred to the second-effect evaporator to replenish its liquid level.

Example 4

A kind of production method of sodium bromide, comprises the following steps:

A: Use chlorine gas to oxidize bromine-containing brine to generate oxidizing liquid, and the chlorine distribution rate of chlorine gas is controlled at 105%;

B: The oxidizing solution is sprayed in from the top of the blowing tower through a spraying device, and is in countercurrent contact with the air blown in from the bottom of the blowing tower, the bromine in the oxidizing solution is blown out and mixed with air to form bromine-containing air, and the bromine is blown out The final oxidizing liquid becomes the blowing waste brine and is discharged from the bottom of the bottom of the blowing tower;

C: Bromine-containing air is discharged from the top of the blowing tower and enters the primary absorption tower. In the primary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid, which is not absorbed. The absorbed bromine enters the secondary absorption tower with the air. In the secondary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid. Enter the third-stage absorption tower until the bromine is completely absorbed, and the air after absorbing the bromine is discharged from the top of the third-stage absorption tower and pumped by the fan to the bottom of the blowing tower as the power source for blowing bromine to the oxidizing liquid;

D: Pass sodium hydroxide solution into the primary absorption tower to adjust the pH of the absorption liquid in the primary absorption tower to 7~8, then the absorption liquid in the primary absorption tower is discharged to the absorption liquid storage tank through overflow, The absorption liquid in the absorption liquid storage tank is poured into the refining kettle at a certain flow rate, and ammonia water is passed into the refining kettle to adjust the color of the absorption liquid in the refining kettle, and then filter to obtain the supernatant;

E: The supernatant is poured into the double-effect evaporator through the feed pump, and in the double-effect evaporator, it is heated by steam and concentrated until sodium bromide crystals are precipitated. After being centrifuged in a centrifuge, solid sodium bromide is obtained. The centrifuged mother liquor is Liquid Sodium Bromide.

The third-stage absorption tower is connected to the sodium formate preparation tank through the absorbent liquid supply pump, the absorption liquid in the third-stage absorption tower overflows to the second-stage absorption tower through the pipeline, and the absorption liquid in the second-stage absorption tower overflows to the first-stage absorption through the pipeline tower.

The concentration of sodium formate solution in the described sodium formate preparation tank is 25%.

The first-level absorption tower, the second-level absorption tower and the third-level absorption tower are all equipped with self-circulating spray pumps, and the flow rate of the bromine-containing air entering the first-level absorption tower is the same as that of the first-level absorption tower, the second-level absorption tower and the third-level absorption tower. The gas-liquid flow ratio of the self-circulating spray flow is 50:1.

Sodium hydroxide is added to the waste blowing brine in step B, and the pH is adjusted to 7.0-8.0 for drying salt or adjusting the pH to the value of the original bromine-containing brine before backfilling.

In step B, the gas-liquid flow ratio of the air entering the blowing tower to the oxidizing liquid sprayed in the blowing tower is 150:1.

When the supernatant in step E is concentrated in the double-effect evaporator, the temperature of the feed liquid in the first-effect evaporator is controlled at 82°C, the temperature of the feed liquid in the second-effect evaporator is controlled at 72°C, and the feed liquid in the second-effect evaporator is When the solid-liquid ratio reaches 3:1, the material in the second-effect evaporator is transferred to the centrifuge, and at the same time, the material in the first-effect evaporator is transferred to the second-effect evaporator to replenish its liquid level.

Example 5

A kind of production method of sodium bromide, comprises the following steps:

A: Use chlorine gas to oxidize bromine-containing brine to generate oxidizing liquid, and the chlorine distribution rate of chlorine gas is controlled at 105%;

B: The oxidizing solution is sprayed in from the top of the blowing tower through a spraying device, and is in countercurrent contact with the air blown in from the bottom of the blowing tower, the bromine in the oxidizing solution is blown out and mixed with air to form bromine-containing air, and the bromine is blown out The final oxidizing liquid becomes the blowing waste brine and is discharged from the bottom of the bottom of the blowing tower;

C: Bromine-containing air is discharged from the top of the blowing tower and enters the primary absorption tower. In the primary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid, which is not absorbed. The absorbed bromine enters the secondary absorption tower with the air. In the secondary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid. Enter the third-stage absorption tower until the bromine is completely absorbed, and the air after absorbing the bromine is discharged from the top of the third-stage absorption tower and pumped by the fan to the bottom of the blowing tower as the power source for blowing bromine to the oxidizing liquid;

D: Pass sodium hydroxide solution into the primary absorption tower to adjust the pH of the absorption liquid in the primary absorption tower to 7~8, then the absorption liquid in the primary absorption tower is discharged to the absorption liquid storage tank through overflow, The absorption liquid in the absorption liquid storage tank is poured into the refining kettle at a certain flow rate, and ammonia water is passed into the refining kettle to adjust the color of the absorption liquid in the refining kettle, and then filter to obtain the supernatant;

E: The supernatant is poured into the double-effect evaporator through the feed pump, and in the double-effect evaporator, it is heated by steam and concentrated until sodium bromide crystals are precipitated. After being centrifuged in a centrifuge, solid sodium bromide is obtained. The centrifuged mother liquor is Liquid Sodium Bromide.

The third-stage absorption tower is connected to the sodium formate preparation tank through the absorbent liquid supply pump, the absorption liquid in the third-stage absorption tower overflows to the second-stage absorption tower through the pipeline, and the absorption liquid in the second-stage absorption tower overflows to the first-stage absorption through the pipeline tower.

The concentration of sodium formate solution in the described sodium formate preparation tank is 25%.

The first-level absorption tower, the second-level absorption tower and the third-level absorption tower are all equipped with self-circulating spray pumps, and the flow rate of the bromine-containing air entering the first-level absorption tower is the same as that of the first-level absorption tower, the second-level absorption tower and the third-level absorption tower. The gas-liquid flow ratio of the self-circulating spray flow is 70:1.

Sodium hydroxide is added to the waste blowing brine in step B, and the pH is adjusted to 7.0-8.0 for drying salt or adjusting the pH to the value of the original bromine-containing brine before backfilling.

In step B, the gas-liquid flow ratio of the air entering the blowing tower to the oxidizing liquid sprayed in the blowing tower is 150:1.

When the supernatant in step E is concentrated in the double-effect evaporator, the temperature of the feed liquid in the first-effect evaporator is controlled at 82°C, the temperature of the feed liquid in the second-effect evaporator is controlled at 72°C, and the feed liquid in the second-effect evaporator is When the solid-liquid ratio reaches 3:1, the material in the second-effect evaporator is transferred to the centrifuge, and at the same time, the material in the first-effect evaporator is transferred to the second-effect evaporator to replenish its liquid level.

Example 6

A kind of production method of sodium bromide, comprises the following steps:

A: Use chlorine gas to oxidize bromine-containing brine to generate oxidizing liquid, and the chlorine distribution rate of chlorine gas is controlled at 105%;

B: The oxidizing solution is sprayed in from the top of the blowing tower through a spraying device, and is in countercurrent contact with the air blown in from the bottom of the blowing tower, the bromine in the oxidizing solution is blown out and mixed with air to form bromine-containing air, and the bromine is blown out The final oxidizing liquid becomes the blowing waste brine and is discharged from the bottom of the bottom of the blowing tower;

C: Bromine-containing air is discharged from the top of the blowing tower and enters the primary absorption tower. In the primary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid, which is not absorbed. The absorbed bromine enters the secondary absorption tower with the air. In the secondary absorption tower, the bromine in the bromine-containing air is absorbed by the absorption liquid to form a mixed solution of sodium bromide and hydrobromic acid. Enter the third-stage absorption tower until the bromine is completely absorbed, and the air after absorbing the bromine is discharged from the top of the third-stage absorption tower and pumped by the fan to the bottom of the blowing tower as the power source for blowing bromine to the oxidizing liquid;

D: Pass sodium hydroxide solution into the primary absorption tower to adjust the pH of the absorption liquid in the primary absorption tower to 7~8, then the absorption liquid in the primary absorption tower is discharged to the absorption liquid storage tank through overflow, The absorption liquid in the absorption liquid storage tank is poured into the refining kettle at a certain flow rate, and ammonia water is passed into the refining kettle to adjust the color of the absorption liquid in the refining kettle, and then filter to obtain the supernatant;

E: The supernatant is poured into the double-effect evaporator through the feed pump, and in the double-effect evaporator, it is heated by steam and concentrated until sodium bromide crystals are precipitated. After being centrifuged in a centrifuge, solid sodium bromide is obtained. The centrifuged mother liquor is Liquid Sodium Bromide.

The third-stage absorption tower is connected to the sodium formate preparation tank through the absorbent liquid supply pump, the absorption liquid in the third-stage absorption tower overflows to the second-stage absorption tower through the pipeline, and the absorption liquid in the second-stage absorption tower overflows to the first-stage absorption through the pipeline tower.

The concentration of sodium formate solution in the described sodium formate preparation tank is 25%.

The first-level absorption tower, the second-level absorption tower and the third-level absorption tower are all equipped with self-circulating spray pumps, and the flow rate of the bromine-containing air entering the first-level absorption tower is the same as that of the first-level absorption tower, the second-level absorption tower and the third-level absorption tower. The gas-liquid flow ratio of the self-circulating spray flow is 70:1.

Sodium hydroxide is added to the blown brine in step B, and the pH is adjusted to 7.0-8.0 for drying salt or adjusting the pH to the value of the original bromine-containing brine before backfilling.

In step B, the gas-liquid flow ratio of the air entering the blowing tower to the oxidizing liquid sprayed in the blowing tower is 200:1.

When the supernatant in step E is concentrated in the double-effect evaporator, the temperature of the feed liquid in the first-effect evaporator is controlled at 82°C, the temperature of the feed liquid in the second-effect evaporator is controlled at 72°C, and the feed liquid in the second-effect evaporator is When the solid-liquid ratio reaches 3:1, the material in the second-effect evaporator is transferred to the centrifuge, and at the same time, the material in the first-effect evaporator is transferred to the second-effect evaporator to replenish its liquid level.

Adopt the process control parameter of embodiment 1-6 respectively, intercept the process index in 1 hour respectively after the continuous operation of the system is stable, draw the following results:

Table 1

As can be seen from the table, the sodium bromide product obtained by the method of the present invention is divided into two kinds of solid sodium bromide product and liquid sodium bromide product, which can meet the needs of different customers, and the purity of the solid sodium bromide obtained simultaneously In addition, by controlling the evaporation temperature and evaporation time of the double-effect evaporator stage, the amount of solid sodium bromide crystallized can be controlled and adjusted, thereby adjusting the concentration of liquid sodium bromide.

It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (10)

1. A kind of production method of sodium bromide is characterized in that comprising the following steps:

   A: Chlorine and bromine-containing brine are mixed in a static mixer to form an oxidizing solution;

   B: The oxidizing solution is sprayed and blown out by air in the blowing tower to obtain bromine-containing air and blown waste brine;

   C: Sodium formate solution is poured into the primary absorption tower, secondary absorption tower and tertiary absorption tower as the absorption liquid, and bromine-containing air is discharged from the top of the blowing tower and then enters the connected primary absorption tower and secondary absorption tower and three-stage absorption tower, the bromine in the bromine-containing air is sequentially absorbed by the absorption liquid in the absorption towers at all levels to form a mixed solution of sodium bromide and hydrobromic acid, and the absorption liquid in the three-stage absorption tower overflows to the second stage through the pipeline The first-level absorption tower, the absorption liquid in the second-level absorption tower overflows to the first-level absorption tower through the pipeline;

   D: The sodium hydroxide solution is passed into the primary absorption tower to adjust the pH of the absorption liquid in the primary absorption tower, and then the absorption liquid in the primary absorption tower is discharged to the absorption liquid storage tank through overflow, and the absorption liquid is stored The absorption liquid in the tank is poured into the refining kettle at a certain flow rate, and ammonia water is passed into the refining kettle to adjust the color of the absorption liquid in the refining kettle, and then filter to obtain the supernatant;

   E: The supernatant is poured into the double-effect evaporator through the feed pump, and in the double-effect evaporator, it is heated by steam and concentrated until sodium bromide crystals are precipitated. After being centrifuged in a centrifuge, solid sodium bromide is obtained. The centrifuged mother liquor is Liquid Sodium Bromide.
2. A kind of production method of sodium bromide as claimed in claim 1, is characterized in that: three-stage absorption tower is communicated with sodium formate preparation tank by absorbent liquid supply pump.
3. A kind of production method of sodium bromide as claimed in claim 2 is characterized in that: the concentration of sodium formate solution in the described sodium formate preparation tank is 20～25%.
4. A kind of production method of sodium bromide as claimed in claim 1, it is characterized in that: one-level absorption tower, two-level absorption tower and three-level absorption tower are all provided with self-circulation spray pump, enter the first-level absorption tower containing The gas-liquid flow ratio of the flow rate of bromine air to the self-circulation spray flow of the primary absorption tower, secondary absorption tower and tertiary absorption tower is 50:1-70:1.
5. The production method of a kind of sodium bromide as claimed in claim 1, it is characterized in that: sodium hydroxide is added to the waste brine in step B, and the pH is adjusted to 7.0-8.0 to carry out salt drying or adjust the pH to the original bromine-containing brine Backfill after the value.
6. A kind of production method of sodium bromide as claimed in claim 1, it is characterized in that: in step A, the chlorine distribution rate of chlorine gas is controlled to be 103%～105%.
7. The production method of a kind of sodium bromide as claimed in claim 1, it is characterized in that: the gas-liquid flow ratio of the air entering the blowing tower and entering the spraying oxidizing liquid in the blowing tower in step B is 150:1～200:1 .
8. A kind of production method of sodium bromide as claimed in claim 1, is characterized in that: in step D, add sodium hydroxide to adjust the pH of absorption liquid to 7～8.
9. The production method of a kind of sodium bromide as claimed in claim 1, it is characterized in that: when the supernatant liquid is concentrated in the double-effect evaporator in step E, the feed liquid temperature in the first-effect evaporator is controlled at 78～82°C , Control the feed liquid temperature in the two-effect evaporator to be 68-72°C.
10. A kind of production method of sodium bromide as claimed in claim 1, it is characterized in that: in the step C, bromine-containing air absorbs bromine, remaining air is discharged from the top of the three-stage absorption tower and is pumped to the blowing tower through fan The bottom is used as the power source for blowing bromine to the oxidizing liquid.

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