CN113479907B - Crystallization method of ammonium fluoride or ammonium bifluoride - Google Patents
Crystallization method of ammonium fluoride or ammonium bifluoride Download PDFInfo
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Abstract
The invention belongs to the technical field of compound production, and particularly relates to a crystallization method of ammonium fluoride or ammonium bifluoride, which comprises the steps of crystallizing by adopting an air-cooled spray cooling tower, reacting in batches by taking anhydrous hydrogen fluoride and liquid ammonia as raw materials, monitoring a reaction end point by a rapid acid-base titration method, pumping a reacted material to the top of the spray tower, falling from the top of the spray tower through a distributor, sequentially passing through two layers of demisters with opposite directions, then re-entering a circulating tank, cooling, then sending to a crystal growing tank for culturing, and separating to obtain a crystal finished product; meanwhile, the mother liquor is recycled after solid-liquid separation, and tail gas is discharged after passing through a three-stage spray tower and the mother liquor. The invention adopts the air-cooled spray cooling tower for crystallization, the cooling speed is high, the yield of finished products is high, and the obtained crystal particles are uniform, compact and stable and meet the requirements of first-class products of national standards; meanwhile, liquid and tail gas in the production process are uniformly and intensively recovered and recycled, no waste liquid or waste residue is generated, and zero-emission production is basically achieved.
Description
Technical Field
The invention belongs to the technical field of compound production, and particularly relates to a crystallization method of ammonium fluoride or ammonium bifluoride.
Background
Ammonium fluoride is a white needle crystal which is easy to absorb moisture, soluble in cold water, slightly soluble in ethanol, decomposed into ammonia and hydrogen fluoride by heating, decomposed into ammonia and ammonium bifluoride in hot water, the aqueous solution of the ammonium bifluoride is acidic, can corrode glass, has a relative density of 1.015, is toxic, has half of death amount (rat, abdominal cavity) of 32mg/kg, is corrosive, and can be used as a chemical reagent, a glass etchant (used together with hydrofluoric acid), a fermentation industry disinfectant and preservative, a solvent for preparing metallic beryllium from beryllium oxide and a surface treating agent for silicon steel plates, and also used for manufacturing ceramics and magnesium alloys, cleaning and descaling of boiler water supply systems and steam generation systems, and acid treatment of oil field gravels, and also used as an alkylation and isomerization catalyst component. Ammonium bifluoride is an important inorganic fluorine salt, white orthorhombic crystal, has the specific gravity of 1.52, the melting point of 124.6 ℃, is easy to deliquesce and agglomerate, is soluble in water and slightly soluble in alcohol, is decomposed into ammonia and ammonium bifluoride in hot water, is decomposed into ammonia and hydrogen fluoride when being heated, has acidic reaction in aqueous solution, can corrode glass and is toxic, is mainly used for passivating metal in phosphate or galvanizing and nickel plating, is used for washing metal to activate the surface, performing rust prevention treatment on the surface of silicon steel plate, utilizing the characteristics of dissolving silica and silicate, is used for acidizing sandstone in oil field by-edge wells to improve the yield, and can also be used for manufacturing an oxidant of ceramic cleaning agents and aluminum-magnesium alloys, removing silicate and other scales in a steam generating system of a boiler water supply system.
Currently, ammonium fluoride or ammonium bifluoride is mainly produced by a liquid phase method, and crystallization methods of the liquid phase method are various and generally divided into a natural cooling mode and a crystallizer mode. And natural cooling crystallization has long crystallization time, serious open air pollution, slow closed heat dissipation and longer crystallization period, and simultaneously, crystal particles formed by natural cooling crystallization have uneven particle size and large deviation.
Meanwhile, ammonium bifluoride has strong corrosivity, equipment is seriously corroded by using a crystallizer made of conventional metal materials, and the I-path plastic material is adopted, so that the plastic has poor heat conductivity and low heat exchange efficiency. In patent CN201510159229.4, a pressurized atomizing spray tower is adopted, air is used for cooling, but material spray enters the top of the tower, an air outlet is also positioned at the top of the tower, atomized small droplets are easily carried out of the spray tower by air flow and enter a tail gas system, and the yield of finished products is reduced. Even the entrained material droplets crystallize in the off-gas line, which can lead to line plugging as production batches increase.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a crystallization method of ammonium fluoride or ammonium bifluoride, which adopts an air-cooled spray cooling tower for crystallization, has high cooling speed and high finished product yield, and obtains uniform, compact and stable crystal particles; the whole process is completed under the condition of closed micro negative pressure, the production environment is good, liquid and tail gas in the production process are uniformly and intensively recycled and recycled, no waste liquid or waste residue is generated, and zero-emission production is basically achieved.
In order to achieve the above object, the present invention provides a crystallization method of ammonium fluoride or ammonium bifluoride, wherein the crystallization method adopts an air-cooled spray cooling tower to perform crystallization, and specifically comprises the following steps:
s1, pumping mother liquor or water into a reaction kettle with a graphite tube array cooling tower, and dividing the amount of anhydrous hydrogen fluoride and the amount of liquid ammonia into a plurality of batches respectively according to theoretical feeding amount;
s2, introducing anhydrous hydrogen fluoride with a first batch of feeding amount into the reaction kettle in a water cooling state, slowly introducing liquid ammonia with the first batch of feeding amount into the reaction kettle, and controlling the flow of the liquid ammonia to ensure that the temperature of a reaction system does not exceed 95 ℃; preferably, when the ammonium fluoride is produced, the temperature of the reaction system does not exceed 90 ℃; when the ammonium bifluoride is produced, the temperature of the reaction system does not exceed 95 ℃.
S3, after the ammonia introduction in the S2 is finished, introducing anhydrous hydrogen fluoride with a second batch of material dosage into the reaction kettle, keeping the temperature of the reaction system not more than 95 ℃, introducing liquid ammonia with a second batch of material dosage into the reaction kettle, keeping the temperature of the reaction system not more than 95 ℃, and sequentially carrying out alternate reaction; preferably, when the ammonium fluoride is produced, the temperature of the reaction system does not exceed 90 ℃; when the ammonium bifluoride is produced, the temperature of the reaction system does not exceed 95 ℃.
S4, after the reaction in the step S3 is finished, sampling from the reaction liquid, monitoring the reaction end point by adopting a rapid acid-base titration method, and controlling the feeding amount of anhydrous hydrofluoric acid or liquid ammonia according to the monitoring result until the reaction is complete;
s5, pumping the completely reacted materials in the reaction kettle of S4 to a circulating tank filled with mother liquor in advance, reducing the temperature of the materials to be below 80 ℃, and stirring and mixing;
s6, pumping the material in the circulating tank in the S5 to the top of the spray tower, enabling the material to fall from the top of the spray tower through a distributor to enable the material to be in contact with cold air from bottom to top in the spray tower, sequentially passing through two layers of demisters in opposite directions, re-entering the circulating tank from the bottom of the spray tower, and circularly cooling the material in such a way to enable the temperature of the material to be reduced to 35-45 ℃; preferably, when the ammonium fluoride is produced, the temperature of the material is reduced to about 35 ℃; when producing ammonium bifluoride, the material temperature is reduced to about 40 ℃.
S7, feeding the cooled material in the S6 circulation tank to a crystal growing tank, and growing crystals;
s8, pumping the crystals cultured in the S7 crystal growing tank to a horizontal centrifuge, feeding the crystals into a packaging tank through a self-unloading material, and packaging to obtain a packaged finished product;
s9, automatically flowing the mother liquor separated in the S8 to a solid-liquid separator, feeding the upper clear liquid into a mother liquor tank, combining the lower solid-liquid mixture with the liquid separated by the gas-liquid separator in the tail gas system, and then feeding the combined liquid back to a circulating tank;
and S10, combining tail gas of equipment facilities, sending the tail gas into a three-stage spray tower, and emptying after mother liquor absorption.
Further, in the technical scheme, in the S1, the anhydrous hydrogen fluoride and the liquid ammonia are respectively divided into 2-5 batches.
Further, when ammonium fluoride is produced in the above technical scheme S4, the rapid acid-base titration method is: taking 2mL of reaction liquid, placing the reaction liquid into a colorimetric tube added with 50mL of water in advance, and dripping 2 drops of 1g/L bromcresol purple indicator liquid to obtain sample liquid; (1) When the sample liquid is purple, comparing with the standard liquid, if the purple of the sample liquid is deeper than the standard liquid, excessive ammonia is contained in the reaction system, and anhydrous hydrofluoric acid is not required to be supplemented, and if the purple of the sample liquid is lighter than the standard liquid, the reaction is complete; (2) When the sample liquid is yellow, titrating to purple with 1mol/L alkaline solution, and recording the volume consumed by the alkaline solution as V:
when V is more than 0.2mL, the ammonia in the reaction system is insufficient, and ammonia needs to be supplemented;
when 0< -V < -0.2ml, the reaction was complete.
Further, in the technical scheme, the standard solution is prepared by measuring 50mL of buffer solution with pH of 6.8, placing the measured solution in a 50mL colorimetric tube, adding 2 drops of 1g/L bromocresol purple indicator solution, and shaking up.
Further, when ammonium bifluoride is produced in the above technical scheme S4, the rapid acid-base titration method is: taking 2mL of reaction liquid, adding 50mL of water, dripping 2-3 drops of phenolphthalein indicator liquid of 10g/L for the first time, titrating to light red by using 1mol/L alkaline solution, and recording the volume consumed by the alkaline solution as V1; adding 20mL of neutral formaldehyde solution for the second time, titrating the solution to light red by using 1mol/L alkaline solution, and recording the volume consumed by the alkaline solution as V2;
when the ratio of (V1-V2) >0.5, ammonia is insufficient in the reaction system, and ammonia needs to be supplemented;
when the (V1-V2) <0, the acid in the reaction system is insufficient, and the anhydrous hydrofluoric acid is required to be supplemented;
when 0< (V1-V2) <0.5, the reaction was complete.
Further, the alkaline solution in the technical scheme is any one of sodium hydroxide, potassium hydroxide, calcium hydroxide and barium hydroxide.
Further, in the above technical solution S6, the distributor is made of a plastic material or a metal material resistant to corrosion by hydrofluoric acid, and preferably, a hastelloy metal material is selected; the demister is a cyclone plate or a baffle plate. Use the distributor among this technical scheme to make the material evenly get into the spray column, be difficult for forming vaporific and taken away by the air current, the whirl board has then further weakened the atomizing possibility of material whereabouts in-process.
Further, the time for growing the crystal in the technical scheme S7 is not more than 24 hours.
Further, in the technical scheme S8, the horizontal centrifuge is an automatic discharge centrifuge made of hydrofluoric acid corrosion-resistant material or a hydrofluoric acid corrosion-resistant material.
Furthermore, the crystallization method in the technical scheme is completed under the condition of closed micro-negative pressure.
The invention has the beneficial effects that:
1. the invention adopts the air-cooled spray cooling tower for crystallization, the cooling speed is high, the material can be uniformly distributed by using the distributor, atomized liquid drops are not easy to be formed and taken away by airflow, meanwhile, demisters such as a rotational flow plate and the like can further weaken the atomization level of the material, and the yield of finished products is high;
2. according to the invention, the amount of anhydrous hydrofluoric acid and liquid ammonia is divided into a plurality of batches for reaction, the input amount of raw materials is well controlled, and the reaction is sufficient; meanwhile, the problems of over-quick temperature rise of a reaction system and escape of raw materials due to the simultaneous existence of a large amount of anhydrous hydrofluoric acid and liquid ammonia are solved, the temperature is controlled, and no raw material is wasted;
3. the invention adopts a rapid acid-base titration method to carry out end point control, has simple, convenient, rapid and accurate operation and stable product quality;
4. the invention can reasonably configure the number of the reaction kettles and the crystal growing tanks, can realize continuous production, and has flexible production mode and high efficiency;
5. the whole production process is simple to operate and easy to control, the reaction end point can be accurately controlled, the crystal particles of the product are uniform and compact, the product quality is kept stable for a long time, and the requirements of first-class products in national standards are met;
6. the whole production process is finished under the condition of closed micro negative pressure, so that the production environment of a workshop is greatly improved, and the method is safe and environment-friendly; materials are conveyed through a pump and a pipeline in the production process, so that the labor intensity is reduced; meanwhile, liquid and tail gas in the production process are uniformly and intensively recovered and recycled, no waste liquid or waste residue is generated, and zero-emission production is basically achieved.
Drawings
FIG. 1 is a flow chart of the production process of the present invention.
Detailed Description
The experimental procedures in the following examples are conventional unless otherwise specified. The raw materials in the following examples are all commercially available products and are commercially available, unless otherwise specified.
FIG. 1 is a production process flow diagram of the present invention, in which an air-cooled spray cooling tower is used for crystallization, anhydrous hydrogen fluoride and liquid ammonia are used as raw materials, the reaction is carried out in batches, the reaction end point is monitored by a rapid acid-base titration method, then the reacted materials are pumped to the top of the spray tower, the materials are mixed with cold mother liquor in a circulation tank, the temperature is reduced to below 80 ℃, the materials fall from the top of the tower through a distributor, sequentially pass through two layers of demisters with opposite directions, and then enter the circulation tank again from the bottom of the tower, when the temperature of the materials is reduced to about 40 ℃, the spraying is stopped, the materials are cooled and then sent to a crystal growing tank for culture, and crystal finished products are obtained through separation; meanwhile, the mother liquor is recycled after solid-liquid separation, and the tail gas is exhausted after being absorbed by the three-stage spray tower and the mother liquor.
The method specifically comprises the following steps:
s1, pumping mother liquor or water into a reaction kettle with a graphite tube array cooling tower, and dividing the amount of anhydrous hydrogen fluoride and the amount of liquid ammonia into a plurality of batches respectively according to theoretical feeding amount; specifically, the method can be divided into 2 batches, 3 batches, 4 batches and 5 batches, and can be set according to the amount of fed materials, and if the batches are too many, the valves of anhydrous hydrofluoric acid and liquid ammonia are closed too frequently and are easy to damage; if the batch is too small, the temperature is not easy to control, and the temperature is increased too fast.
S2, introducing anhydrous hydrogen fluoride with a first batch of feeding amount into the reaction kettle in a water cooling state, slowly introducing liquid ammonia with the first batch of feeding amount into the reaction kettle, and controlling the flow of the liquid ammonia to ensure that the temperature of a reaction system does not exceed 95 ℃; specifically, the reaction system temperature should not exceed 90 ℃ when ammonium fluoride is produced, and the reaction system temperature should not exceed 95 ℃ when ammonium bifluoride is produced.
S3, after the ammonia introduction in the S2 is finished, introducing anhydrous hydrogen fluoride with a second batch of material dosage into the reaction kettle, keeping the temperature of the reaction system not more than 95 ℃, introducing liquid ammonia with a second batch of material dosage into the reaction kettle, keeping the temperature of the reaction system not more than 95 ℃, and sequentially carrying out alternate reaction; specifically, the reaction system temperature should not exceed 90 ℃ when ammonium fluoride is produced, and the reaction system temperature should not exceed 95 ℃ when ammonium bifluoride is produced.
S4, after the reaction in the step S3 is finished, sampling from the reaction liquid, monitoring the reaction end point by adopting a rapid acid-base titration method, and controlling the feeding amount of anhydrous hydrofluoric acid or liquid ammonia according to the monitoring result until the reaction is complete;
s5, pumping the completely reacted materials in the reaction kettle of the S4 to a circulating tank filled with mother liquor in advance, reducing the temperature of the materials to be below 80 ℃, and stirring and mixing;
s6, pumping the material in the circulating tank in the S5 to the top of the spray tower, enabling the material to fall from the top of the spray tower through a distributor to enable the material to be in contact with cold air from bottom to top in the spray tower, sequentially passing through two layers of demisters in opposite directions, re-entering the circulating tank from the bottom of the spray tower, and circularly cooling the material in such a way to enable the temperature of the material to be reduced to 35-45 ℃;
s7, pumping the cooled material in the S6 circulating tank to a crystal growing tank, and growing crystals;
s8, pumping the crystals cultured in the S7 crystal growing tank to a horizontal centrifuge, feeding the crystals into a packaging tank through a self-unloading material, and packaging to obtain a finished product of ammonium fluoride or ammonium bifluoride; specifically, the horizontal centrifuge adopts an automatic discharge centrifuge, and preferably adopts a hydrofluoric acid corrosion prevention measure or is made of a hydrofluoric acid corrosion resistant material.
S9, automatically flowing the mother liquor separated in the S8 to a solid-liquid separator, allowing the upper clear liquid to enter a mother liquor tank, combining the lower solid-liquid mixture with the liquid separated by the gas-liquid separator in the tail gas system, and then returning the mixture to a circulating tank;
and S10, combining tail gas of equipment facilities, sending the tail gas into a three-stage spray tower, and emptying after mother liquor absorption.
When the ammonium fluoride is produced, the method adopts a rapid acid-base titration method as follows: taking 2mL of reaction solution, putting the reaction solution into a colorimetric tube added with 50mL of water in advance, and dripping 2 drops of 1g/L bromocresol purple indicator solution to obtain sample solution; (1) When the sample liquid is purple, comparing with the standard liquid, if the purple of the sample liquid is deeper than the standard liquid, excessive ammonia is contained in the reaction system, and anhydrous hydrofluoric acid is not required to be supplemented, and if the purple of the sample liquid is lighter than the standard liquid, the reaction is complete; (2) When the sample liquid is yellow, titrating to purple with 1mol/L alkaline solution, and recording the consumed volume of the alkaline solution as V:
when V is more than 0.2mL, the ammonia in the reaction system is insufficient, and ammonia needs to be supplemented;
when 0 s were constructed from V-s-unders 0.2ml, the reaction was complete.
Specifically, the standard solution is prepared by weighing 50mL buffer solution with pH of 6.8, placing in a 50mL colorimetric tube, adding 2 drops of 1g/L bromcresol purple indicator solution, and shaking up.
Specifically, the alkaline solution may be a strong alkaline solution such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and barium hydroxide, which are readily soluble in water.
Specifically, the detection mechanism of the rapid acid-base titration method is as follows: the color change pH range of the bromocresol purple indicator is 5.2 (yellow) to 6.8 (violet), where the color change is gradually lighter yellow; when the pH value is 5.7-5.8, the color is almost colorless, gradually changes to light blue along with the gradual increase of the pH value, and gradually deepens from the light blue to purple. Therefore, when the sample liquid is darker in violet than the standard liquid, it indicates that the amount of free ammonia in the system is excessive and the amount of liquid ammonia is excessive. When the indicator added into the reaction solution is yellow, titrating with an alkaline solution to titrate weak acid salt as strong base, wherein the pH jump range is 0.2 percent around the stoichiometric point, and the pH value is 5.2-5.7, still can be determined as the stoichiometric point; the reaction was complete when less than 0.2mL of NaOH was consumed by titration.
Specifically, during the detection control of the reaction end point, the sampling amount is automatically set according to the solid content in the reaction liquid, and the relatively more accurate area of the burette scale of the consumption volume of the alkaline solution every time is controlled. The alkaline concentration is not limited to 1mol/L, but the concentration of the alkaline solution is increased, the pH jump range is expanded, and the end point control is not facilitated; the concentration of the alkaline solution is reduced, the pH jump range is reduced, and according to the pH jump change rule of strong base titration weak acid salt, when the concentration is 0.1mol/L, the pH jump range is about 5.3-6.5, but the dosage of the titration solution is increased, and the detection time is increased. The end point judgment basis is not limited to 0.2-0mL, and the detection data of the reaction end point, the quality data of the finished product and the concentration of the titration solution are determined.
When the ammonium bifluoride is produced, the rapid acid-base titration method is adopted as follows: taking 2mL of reaction liquid, adding 50mL of water, dripping 2-3 drops of 10g/L phenolphthalein indicator liquid for the first time, titrating to light red by using 1mol/L alkaline solution, and recording the volume consumed by the alkaline solution as V1; adding 20mL of neutral formaldehyde solution for the second time, titrating the solution to light red by using 1mol/L alkaline solution, and recording the volume consumed by the alkaline solution as V2;
when the ratio of (V1-V2) >0.5, ammonia is insufficient in the reaction system, and ammonia needs to be supplemented;
when the (V1-V2) <0, the acid in the reaction system is insufficient, and the anhydrous hydrofluoric acid is required to be supplemented;
when 0< (V1-V2) <0.5, the reaction was complete.
Specifically, the alkaline solution used may be a strong alkaline solution such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and barium hydroxide that is easily soluble in water, but the alkaline solution used for the two titrations must be a solution prepared in the same batch for each detection.
Specifically, the detection mechanism of the rapid acid-base titration method is as follows:
first titration: NH (NH) 4 HF 2 +NaOH→NH4F+NaF+H 2 O
Second titration: 4NH 4 F+6HCHO→(CH 2 ) 6 N 4 +4HF+6H 2 O
HF+NaOH→NaF+H 2 O
Specifically, the invention adopts a twice acid-base titration method to carry out reaction end point detection control, the sampling amount is automatically set according to the solid content in the reaction liquid, and the relatively more accurate scale region of the burette is controlled when the alkaline solution consumes the volume each time. The alkaline concentration is not limited to 1mol/L, but the pH jump range is enlarged when the concentration of the alkaline solution is increased, which is not beneficial to the end point control; the concentration of the alkaline solution is reduced, the dosage of the titration solution is increased, and the detection time is increased. The endpoint judgment basis is not limited to 0.5-0mL, and the reaction endpoint detection data, the finished product quality data and the concentration of the titration solution are determined in the early stage.
The distributor can be made of plastic or metal resistant to corrosion of hydrofluoric acid, can effectively prevent the distributor from being corroded by hydrofluoric acid and prolong the service life of the distributor, and particularly can be made of Hastelloy; the demister is a cyclone plate or a baffle plate.
In the crystal growing process, the crystal growth time is not more than 24 hours because the ammonium fluoride and the ammonium bifluoride crystals are easy to form walls; specifically, it may be 2h, 3h, 4h, 5h … … h.
The horizontal centrifuge adopted in the invention adopts an automatic discharge centrifuge which is made of hydrofluoric acid corrosion prevention measures or hydrofluoric acid corrosion resistant materials, so that the production continuity can be ensured, the equipment is effectively prevented from being corroded, and the service life of the equipment is prolonged.
The whole production process of the invention is completed under the condition of closed micro negative pressure, and the production environment of a workshop can be greatly improved. Particularly, materials are conveyed through a pump and a pipeline in the production process, so that the labor intensity of workers can be reduced by about 75%; the tail gas in the production process is uniformly and intensively recycled and recycled, no waste liquid or waste residue is generated, and zero-emission production is basically achieved.
The present invention is described in further detail below with reference to examples:
example 1
A crystallization method of ammonium fluoride adopts an air-cooled spray cooling tower for crystallization, and specifically comprises the following steps:
s1, pumping 1t of ammonium fluoride mother liquor into a reaction kettle with a graphite tube array cooling tower, and dividing the amount of anhydrous hydrogen fluoride and the amount of liquid ammonia into 2 batches respectively according to theoretical feeding amount;
s2, introducing 270kg of anhydrous hydrogen fluoride with a first batch of feeding amount into the reaction kettle in a water cooling state, slowly introducing 233kg of liquid ammonia with the first batch of feeding amount into the reaction kettle, and controlling the flow of the liquid ammonia to ensure that the temperature of a reaction system does not exceed 85 ℃;
s3, after the ammonia introduction of S2 is finished, introducing 270kg of anhydrous hydrogen fluoride with a second batch of feeding amount into the reaction kettle, keeping the temperature of a reaction system not to exceed 85 ℃, introducing 232kg of liquid ammonia with the second batch of feeding amount into the reaction kettle, and keeping the temperature of the reaction system not to exceed 85 ℃;
s4, after the reaction in the S3 is finished, taking 2mL of reaction liquid, adding 50mL of water and 2 drops of 1g/L bromocresol purple indicator liquid, wherein the solution is purple and is lighter than the standard solution, and the reaction is complete;
s5, pumping the completely reacted materials in the reaction kettle of S4 to a circulating tank filled with mother liquor in advance, reducing the temperature of the materials to be below 80 ℃, and stirring and mixing;
s6, pumping the material in the circulating tank in the S5 to the top of the spray tower, enabling the material to fall from the top of the spray tower through a distributor to enable the material to be in contact with cold air from bottom to top in the spray tower, sequentially passing through two layers of demisters in opposite directions, re-entering the circulating tank from the bottom of the spray tower, and circularly cooling the material in such a way to enable the temperature of the material to be reduced to 35 ℃;
s7, pumping the cooled material in the S6 circulation tank to a crystal growing tank, and culturing crystals for 2 hours;
s8, conveying the crystals cultured in the S7 crystal growing tank to a horizontal centrifuge for centrifugation, feeding the crystals into a packaging tank through self-unloading materials, packaging to obtain 994kg of ammonium fluoride crystals, and ensuring that the conversion rate of finished products reaches 98.91 percent
S9, automatically flowing the mother liquor separated in the S8 to a solid-liquid separator, feeding the upper clear liquid into a mother liquor tank, combining the lower solid-liquid mixture with the liquid separated by the gas-liquid separator in the tail gas system, and then feeding the combined liquid back to a circulating tank;
and S10, combining tail gas of each equipment facility, sending the tail gas into a three-stage spray tower, and emptying after absorbing mother liquor.
Example 2
A crystallization method of ammonium bifluoride adopts an air-cooled spray cooling tower for crystallization, and specifically comprises the following steps:
s1, pumping 2t of ammonium bifluoride mother liquor into a reaction kettle with a graphite tube array cooling tower, and dividing the amount of anhydrous hydrogen fluoride and the amount of liquid ammonia into 3 batches respectively according to theoretical feeding amount;
s2, introducing 700kg of anhydrous hydrogen fluoride with a first batch of feeding amount into the reaction kettle in a water cooling state, then slowly introducing 299kg of liquid ammonia with the first batch of feeding amount into the reaction kettle, and controlling the flow of the liquid ammonia to ensure that the temperature of a reaction system does not exceed 93 ℃;
s3, after the ammonia introduction of S2 is finished, introducing 700kg of anhydrous hydrogen fluoride with a second batch of feeding amount into the reaction kettle, keeping the temperature of the reaction system not to exceed 93 ℃, and introducing 298kg of liquid ammonia with the second batch of feeding amount into the reaction kettle, keeping the temperature of the reaction system not to exceed 93 ℃;
s4, after the ammonia introduction in the S3 is finished, introducing 700kg of anhydrous hydrogen fluoride with a third batch of material dosage into the reaction kettle, keeping the temperature of a reaction system not to exceed 93 ℃, introducing 298kg of liquid ammonia with a third batch of material dosage into the reaction kettle, and keeping the temperature of the reaction system not to exceed 93 ℃;
s5, after the reaction of S4 is finished, taking 2mL of reaction liquid, adding 50mL of water and 3 drops of 10g/L phenolphthalein indicator liquid, titrating the reaction liquid to light red by using 1mol/L sodium hydroxide solution, and consuming 16.52mL of the sodium hydroxide solution. Adding 20mL of neutral formaldehyde solution into the titration solution, fading the light red color, titrating the titration solution again to the light red color by using 1mol/L of sodium hydroxide solution, consuming 16.26mL of the sodium hydroxide solution, (V1-V2) =0.26mL, and completely reacting;
s6, pumping the completely reacted materials in the reaction kettle of the S5 to a circulating tank filled with mother liquor in advance, reducing the temperature of the materials to be below 80 ℃, and stirring and mixing;
s7, pumping the material in the circulation tank in the S6 to the top of the spray tower, enabling the material to fall from the top of the spray tower through a distributor to enable the material to be in contact with cold air from bottom to top in the spray tower, sequentially passing through two layers of demisters with opposite directions, re-entering the circulation tank from the bottom of the spray tower, and circularly cooling the material in such a way to enable the temperature of the material to be reduced to 42 ℃;
s8, pumping the cooled material in the S7 circulation tank to a crystal growing tank, and culturing crystals for 2 hours;
s9, conveying the crystals cultured in the S8 crystal growing tank to a horizontal centrifuge for centrifugation, feeding the crystals into a packaging tank through self-unloading materials, and packaging to obtain 2990kg of ammonium bifluoride crystals, wherein the conversion rate of finished products is as high as 99.83%.
S10, automatically flowing the mother liquor separated in the S9 to a solid-liquid separator, allowing the upper clear liquid to enter a mother liquor tank, combining the lower solid-liquid mixture with the liquid separated by the gas-liquid separator in the tail gas system, and then returning the mixture to a circulating tank;
and S11, combining tail gas of equipment facilities, sending the tail gas into a three-stage spray tower, and emptying after mother liquor absorption.
Detection and analysis: the quality of the ammonium fluoride produced in example 1 was tested according to the test method in the "industrial ammonium fluoride" GB/T28653-2012 standard, and the results are shown in table 1; the quality of the ammonium bifluoride produced in example 2 was measured according to the method of detection in the standard GB/T28655-2012, and the results are shown in Table 2.
TABLE 1 ammonium fluoride test results
| Item | Example 1 | First-class article in GB/T28653-2012 |
| Ammonium fluoride w/%) | 95.42 | ≥95.0 |
| Free acid (as HF) w/%) | 0 | ≤1.0 |
| Fluosilicic acid [ in (NH) 4 ) 2 SiF 6 Meter]w/％ | 0.34 | ≤0.5 |
As can be seen from the results in Table 1, the ammonium fluoride produced by the preparation method of the invention has excellent quality, and meets the requirements of first-class products in GB/T28653-2012.
TABLE 2 ammonium bifluoride assay results
As can be seen from the results in Table 2, the quality of the ammonium bifluoride produced by the preparation method is excellent and meets the requirements of first-class products in GB/T28655-2012.
In conclusion, the crystallization method of ammonium fluoride or ammonium bifluoride adopts the air-cooled spray cooling tower for crystallization, has high cooling speed, simple operation in the whole production process, easy control and accurate control of the reaction end point, and can obtain products with uniform, compact and stable crystal particles and high yield, thereby meeting the requirements of first-class products in national standards; meanwhile, liquid and tail gas in the production process are uniformly and intensively recovered and recycled, no waste liquid or waste residue is generated, and zero-emission production is basically achieved.
Finally, it should be emphasized that the above-described preferred embodiments of the present invention are merely examples of implementations, and it should be understood that various changes and modifications may be made by those skilled in the art, and any changes, equivalents, improvements and the like, which fall within the spirit and principle of the present invention, should be included in the scope of the present invention.
Claims (8)
1. A crystallization method of ammonium fluoride or ammonium bifluoride is characterized in that the crystallization method adopts an air-cooled spray cooling tower for crystallization, and specifically comprises the following steps:
s1, pumping mother liquor or water into a reaction kettle with a graphite tube array cooling tower, and dividing the amount of anhydrous hydrofluoric acid and the amount of liquid ammonia into a plurality of batches respectively according to theoretical feeding amount;
s2, introducing anhydrous hydrofluoric acid with a first batch of feeding amount into the reaction kettle in a water cooling state, then slowly introducing liquid ammonia with the first batch of feeding amount into the reaction kettle, and controlling the flow of the liquid ammonia to ensure that the temperature of a reaction system does not exceed 95 ℃;
s3, after the liquid ammonia is fed in the S2, feeding anhydrous hydrofluoric acid with a second batch of feeding amount into the reaction kettle, keeping the temperature of the reaction system not more than 95 ℃, feeding liquid ammonia with a second batch of feeding amount into the reaction kettle, keeping the temperature of the reaction system not more than 95 ℃, and sequentially and alternately reacting;
s4, after the reaction in the step S3 is finished, sampling from the reaction liquid, monitoring the reaction end point by adopting a rapid acid-base titration method, and controlling the feeding amount of anhydrous hydrofluoric acid or liquid ammonia according to the monitoring result until the reaction is complete;
s5, pumping the completely reacted materials in the reaction kettle of S4 to a circulating tank filled with mother liquor in advance, reducing the temperature of the materials to be below 80 ℃, and stirring and mixing;
s6, pumping the material in the circulating tank in the S5 to the top of the spray tower, enabling the material to fall from the top of the spray tower through a distributor to enable the material to be in contact with cold air from bottom to top in the spray tower, sequentially passing through two layers of demisters in opposite directions, re-entering the circulating tank from the bottom of the spray tower, and circularly cooling the material in such a way to enable the temperature of the material to be reduced to 35-45 ℃;
s7, feeding the cooled material in the S6 circulation tank to a crystal growing tank, and growing crystals;
s8, pumping the crystals cultured in the S7 crystal growing tank to a horizontal centrifuge, feeding the crystals into a packaging tank through a self-unloading material, and packaging to obtain a packaged finished product;
s9, automatically flowing the mother liquor separated in the S8 to a solid-liquid separator, allowing the upper clear liquid to enter a mother liquor tank, combining the lower solid-liquid mixture with the liquid separated by the gas-liquid separator in the tail gas system, and then returning the mixture to a circulating tank;
s10, combining tail gas of equipment facilities, sending the tail gas into a three-stage spray tower, and emptying after mother liquor absorption;
in S4, when ammonium fluoride is produced, the rapid acid-base titration method comprises the following steps: taking 2mL of reaction solution, putting the reaction solution into a colorimetric tube added with 50mL of water in advance, and dripping 2 drops of 1g/L bromocresol purple indicator solution to obtain sample solution; (1) When the sample liquid is purple, comparing with the standard liquid, if the purple of the sample liquid is deeper than the standard liquid, the liquid ammonia in the reaction system is excessive, and the anhydrous hydrofluoric acid is required to be supplemented, and if the purple of the sample liquid is lighter than the standard liquid, the reaction is complete; (2) When the sample liquid is yellow, titrating to purple with 1mol/L alkaline solution, and recording the consumed volume of the alkaline solution as V:
when V is more than 0.2mL, the liquid ammonia in the reaction system is insufficient, and liquid ammonia needs to be supplemented;
when 0-woven fabric V-woven fabric is 0.2ml, the reaction is complete;
in S4, when ammonium bifluoride is produced, the rapid acid-base titration method comprises the following steps: taking 2mL of reaction liquid, adding 50mL of water, dripping 2-3 drops of 10g/L phenolphthalein indicator liquid for the first time, titrating to light red by using 1mol/L alkaline solution, and recording the volume consumed by the alkaline solution as V1; adding 20mL of neutral formaldehyde solution for the second time, titrating the solution to light red by using 1mol/L alkaline solution, and recording the volume consumed by the alkaline solution as V2;
when the (V1-V2) >0.5, the liquid ammonia in the reaction system is insufficient, and the liquid ammonia needs to be supplemented;
when the (V1-V2) <0, the acid in the reaction system is insufficient, and the anhydrous hydrofluoric acid is required to be supplemented;
when 0< (V1-V2) <0.5, the reaction was complete.
2. The method for crystallizing ammonium fluoride or ammonium bifluoride according to claim 1, wherein the anhydrous hydrofluoric acid and the liquid ammonia are divided into 2 to 5 batches in S1.
3. The method for crystallizing ammonium fluoride or ammonium bifluoride according to claim 1, wherein the standard solution is prepared by measuring 50mL of a buffer solution with pH of 6.8, placing the buffer solution in a 50mL colorimetric tube, adding 2 drops of 1g/L bromcresol purple indicator solution, and shaking up.
4. The method for crystallizing ammonium fluoride or ammonium bifluoride according to claim 1, wherein the alkaline solution is any one of sodium hydroxide, potassium hydroxide, calcium hydroxide and barium hydroxide.
5. The method according to claim 1, wherein the distributor in S6 is made of a plastic material or a metal material resistant to corrosion by hydrofluoric acid; the demister is a cyclone plate or a baffle plate.
6. The method for crystallizing ammonium fluoride or ammonium bifluoride as claimed in claim 1, wherein said time for growing crystals in S7 is not more than 24 hours.
7. The method for crystallizing ammonium fluoride or ammonium bifluoride as claimed in claim 1, wherein in S8, the horizontal centrifuge is an automatic discharge centrifuge made of a material having hydrofluoric acid corrosion resistance or a hydrofluoric acid corrosion resistance.
8. The crystallization method of ammonium fluoride or ammonium bifluoride according to claim 1, wherein the crystallization method is performed under a closed micro-negative pressure condition.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4026997A (en) * | 1973-09-21 | 1977-05-31 | Bayer Aktiengesellschaft | Process for the production of ammonium fluoride from fluosilicic acid |
| CN102689876A (en) * | 2011-03-25 | 2012-09-26 | 精工爱普生株式会社 | Separating method and separating apparatus |
| CN108910916A (en) * | 2018-08-20 | 2018-11-30 | 福建永晶科技股份有限公司 | A kind of preparation method and its preparation system of ammonium acid fluoride |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2816818A (en) * | 1954-12-31 | 1957-12-17 | Int Minerals & Chem Corp | Process for the preparation of ammonium fluoride |
| US3106449A (en) * | 1961-07-17 | 1963-10-08 | Grace W R & Co | Production of ammonium hydrogen fluoride |
| CN1385369A (en) * | 2002-01-15 | 2002-12-18 | 姜仁和 | Proces for direct synthesizing fluoammonium salt |
| CN101269816A (en) * | 2008-05-16 | 2008-09-24 | 夏克立 | Method for producing fluorine series compounds and white carbon black |
| CN103803584B (en) * | 2012-11-08 | 2016-03-02 | 福建省邵武市永飞化工有限公司 | Ammonium bifluoride preparation method |
| CN103303941B (en) * | 2013-05-30 | 2014-12-17 | 福建省邵武市永飞化工有限公司 | Preparation method of ammonium fluoride |
| CN106145160A (en) * | 2015-04-03 | 2016-11-23 | 东至天孚化工有限公司 | A kind of ammonium acid fluoride production method |
| CN106608646A (en) * | 2015-11-22 | 2017-05-03 | 宁夏际华环境安全科技有限公司 | Production process for ammonium fluoride |
| CN107540001A (en) * | 2016-06-29 | 2018-01-05 | 宁夏海诚电化信息科技有限公司 | A kind of ammonium acid fluoride production technology |
| CN107879360B (en) * | 2017-12-19 | 2023-09-05 | 浙江朗泰环境工程有限公司 | Ammonium bifluoride mother liquor cooling system |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4026997A (en) * | 1973-09-21 | 1977-05-31 | Bayer Aktiengesellschaft | Process for the production of ammonium fluoride from fluosilicic acid |
| CN102689876A (en) * | 2011-03-25 | 2012-09-26 | 精工爱普生株式会社 | Separating method and separating apparatus |
| CN108910916A (en) * | 2018-08-20 | 2018-11-30 | 福建永晶科技股份有限公司 | A kind of preparation method and its preparation system of ammonium acid fluoride |
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