Device for producing ammonium fluoride and ammonium bifluoride from ammonium fluosilicate

Abstract

A device for producing ammonium fluoride and ammonium bifluoride by using ammonium fluosilicate, comprising an ammonium fluoride reaction unit, a white carbon black drying unit, an ammonium bifluoride reaction unit, a fluorinated salt liquid concentration unit, a drying unit, a tail gas treatment unit and a sealing unit. The device has simple structure, good continuity, less auxiliary materials and low production cost. Ammonium fluoride, white carbon black, ammonium bifluoride and purified fluosilicic acid are prepared by using ammonium fluosilicate solid waste as raw material, which turns waste into treasure, greatly reduces the cost of hazardous waste treatment, and realizes the rationalization of waste resources. The process conditions are easy to realize, the operation is simple, it is convenient for large-scale production, and the economic benefit is obvious.

Description

Technical Field

[0001] This utility model belongs to the field of chemical production equipment technology, specifically relating to an apparatus for producing ammonium fluoride and ammonium hydrogen fluoride using ammonium fluorosilicate. Background Technology

[0002] Ammonium fluoride (NH4F) and ammonium bifluoride (NH4HF2) are important fluorochemical products with wide applications in various industrial sectors. Ammonium fluoride is commonly used in glass etching, sterilization in the brewing industry, and metal surface polishing; while ammonium bifluoride plays a crucial role in ceramic manufacturing, beryllium smelting, and oilfield acidification. Both have stable market demand and promising application prospects.

[0003] However, traditional processes for producing ammonium fluoride and ammonium bifluoride rely heavily on non-renewable resources such as fluorite, which are not only costly but also prone to environmental pollution during mining and processing. Meanwhile, large quantities of ammonium fluorosilicate ((NH4)2SiF6) are produced as a byproduct in the wet-process phosphoric acid production of the phosphate fertilizer industry, as well as in the semiconductor and new energy industries. For a long time, my country has primarily focused on converting ammonium fluorosilicate into sodium fluorosilicate. However, due to the limited application scope and poor market benefits of sodium fluorosilicate, fluorine and silicon resources have not been effectively utilized, hindering the sustainable development of the phosphate fertilizer and related industries and causing significant environmental problems.

[0004] Developing a technology that can efficiently convert ammonium fluorosilicate into high-value-added ammonium fluoride and ammonium bifluoride would not only help alleviate the pressure on fluorite resources but also realize the resource utilization of industrial by-products, offering significant environmental and economic benefits. Currently, although some research has focused on the conversion pathway of ammonium fluorosilicate, problems such as low conversion efficiency, unstable product quality, complex processes, and difficulties in controlling environmental pollution still exist in industrial implementation.

[0005] Therefore, there is an urgent need to provide a new type of equipment and supporting production method that can operate continuously and stably, is environmentally friendly and has high conversion efficiency, in order to achieve the efficient and clean conversion of ammonium fluorosilicate to ammonium fluoride and ammonium bifluoride, meet the growing market demand and promote the green transformation of related industries. Summary of the Invention

[0006] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a device for producing ammonium fluoride and ammonium bifluoride from ammonium fluorosilicate that has a simple structure, good continuity, uses fewer auxiliary materials, and saves production costs.

[0007] The technical solution adopted to solve the above technical problems is: an apparatus for producing ammonium fluoride and ammonium hydrogen fluoride using ammonium fluorosilicate, including an ammonium fluoride reaction unit, a silica drying unit, an ammonium hydrogen fluoride reaction unit, a fluoride salt solution concentration unit, a drying unit, a tail gas treatment unit, and a sealing unit;

[0008] The ammonium fluoride reaction unit is as follows: solid ammonium fluorosilicate is added to the ammonium fluoride reaction tank from the feeding tank; an ammonia pump pumps ammonia water from the ammonia tank into the ammonium fluoride reaction tank; the ammonium fluoride reaction tank is connected to the ammonium fluoride reaction tank and the silica filter press respectively through a crude ammonium fluoride liquid filtration pump installed on the pipeline; the outlet of the silica filter press is connected to the silica drying unit; one outlet of the silica filter press is connected to the ammonium fluoride reaction tank, one outlet is connected to the silica washing water storage tank, and one outlet is connected to the ammonium fluoride solution storage tank; the silica washing water storage tank is connected to the silica washing water storage tank and the ammonium fluoride reaction tank through a silica washing liquid pump installed on the pipeline; the evaporation condensate storage tank and the process water storage tank are connected to the silica filter press through the silica washing water pump.

[0009] The aforementioned silica drying unit is a silica drying device;

[0010] The ammonium bifluoride reaction unit comprises: an ammonium fluoride solution storage tank connected to a first ammonium bifluoride reaction tank and a second ammonium bifluoride reaction tank via an ammonium fluoride liquid feed pump installed on a pipeline; a 50% hydrofluoric acid storage tank connected to the first ammonium bifluoride reaction tank and the second ammonium bifluoride reaction tank via a hydrofluoric acid feed pump installed on a pipeline; and the outlets of the first and second ammonium bifluoride reaction tanks connected to the first and second ammonium bifluoride reaction tanks via an ammonium fluoride liquid feed pump installed on a pipeline, and connected to a fluoride salt solution concentration unit via one of the pumps.

[0011] The fluoride salt concentration unit comprises: an ammonium fluoride solution storage tank connected to a first-effect evaporator and a second-effect evaporator via an ammonium fluoride solution feed pump installed on a pipeline; an ammonium bifluoride reaction tank connected to a first-effect evaporator and a second-effect evaporator via an ammonium bifluoride solution feed pump installed on a pipeline; the top outlet of the first-effect evaporator connected to a first-effect separator, and the bottom outlet connected to a steam condensate tank; the top outlet of the steam condensate tank connected in one path to a steam condensate cooler, and in another path to the first-effect separator and the second-effect evaporator; and the bottom of the steam condensate tank connected to a steam condensate pump installed on a pipeline. One path is connected to the saturator, another to the steam condensate tank, and yet another to the steam condensate storage tank. The bottom outlet of the first-effect separator is connected to the inlet of the first-effect hydrocyclone via a first-effect slurry pump installed on a pipeline. The middle outlet is connected to the first-effect evaporator via a first-effect circulation pump installed on a pipeline. The top outlet of the first-effect hydrocyclone is connected to the first-effect separator. The top outlet of the second-effect evaporator is connected to the second-effect separator, and its lower outlet is connected to the steam condensate tank. The top outlet of the second-effect separator is connected to the first condenser, its middle outlet is connected to the second-effect evaporator via a second-effect circulation pump installed on a pipeline, and its bottom outlet is connected to... A double-effect slurry pump installed on the pipeline is connected to the inlet of the double-effect hydrocyclone. The top outlet of the double-effect hydrocyclone is connected to the double-effect separator. The bottom outlets of both the first-effect and second-effect hydrocyclones are connected to the thickener. Ammonia water from the ammonia tank is pumped into the ammonia water metering tank, which is connected to the thickener. The outlet of the thickener is connected to the filter. Both the filter and the thickener are connected to the mother liquor tank. The mother liquor tank is connected to the double-effect separator via a mother liquor pump installed on the pipeline. The filter hopper of the filter is set to correspond to the drying feed conveyor. The drying feed conveyor sends the material into the vibrating fluidized bed dryer. The air heater utilizes... The cold air supplied by the drying blower is heated by the introduced live steam. The heated air is then sent to the vibrating fluidized bed dryer. A packaging conveyor is installed at the discharge port of the vibrating fluidized bed dryer, and a metering packaging machine is installed at the discharge end of the packaging conveyor. The evaporation condensate from the double-effect evaporator enters the first condenser. The first condenser is connected to the second condenser and the evaporation condensate tank. The second condenser is also connected to the evaporation condensate tank. The evaporation condensate tank is connected to the evaporation condensate storage tank through an evaporation condensate pump installed on the pipeline. The non-condensable gas discharged from the second condenser enters the vacuum unit. The wastewater from the vacuum unit is discharged to the silica washing water storage tank.

[0012] The exhaust gas treatment unit comprises: non-condensable gas from the vibrating fluidized bed dryer is discharged into a drying dust collector; non-condensable gas discharged from the drying dust collector is fed into a drying exhaust gas scrubbing tower; the lower outlet of the drying exhaust gas scrubbing tower is connected to the upper part of the drying exhaust gas scrubbing tower via a drying scrubbing circulation pump installed on a pipeline, and to a drying exhaust gas scrubbing cooler via another pipeline; the top outlet of the drying exhaust gas scrubbing tower is connected to a primary exhaust gas absorption tower via a drying induced draft fan; the drying exhaust gas scrubbing cooler is connected to the drying exhaust gas scrubbing tower; and the unit includes an ammonia tank, an ammonium fluoride reaction tank, a silica washing water storage tank, an evaporation condensate storage tank, an ammonium fluoride solution storage tank, a 50% hydrofluoric acid storage tank, and a first ammonium hydrogen fluoride reaction tank. The system consists of a second ammonium bifluoride reaction tank, a filter, a mother liquor tank, a vibrating fluidized bed dryer, a vacuum unit, a sealed water tank, a thickener, and an ammonia metering tank. Non-condensable gas is introduced into the primary tail gas absorption tower via a tail gas induced draft fan. The gas is introduced into the lower outlet of the primary tail gas absorption tower and connected to the middle and upper parts of the primary tail gas absorption tower via a primary tail gas absorption circulation pump installed on a pipeline. The top of the primary tail gas absorption tower is connected to the secondary tail gas absorption tower. The lower part of the secondary tail gas absorption tower is connected to the primary tail gas absorption tower via a secondary tail gas absorption circulation pump installed on a pipeline, and connected to the middle and upper parts of the secondary tail gas absorption tower via another pipeline. The remaining tail gas in the secondary tail gas absorption tower then enters the alkaline washing tower for further absorption.

[0013] The sealing unit is as follows: mechanical seal return water from each pump enters the sealing water tank for cooling, and the cooled mechanical seal water is pumped back to the mechanical seal water inlet of each pump or to the silica washing water storage tank through the sealing water pump.

[0014] The outlet of the thickener of this invention is connected to a cold water tank, which is connected to a chiller via a cold water circulation pump installed on a pipeline, and the chiller is connected to the thickener.

[0015] The circulating water of the steam condensate cooler, the dry exhaust gas scrubbing cooler, the vacuum unit, the sealed water tank, and the refrigeration unit of this utility model is fed into the cooling tower. After being cooled by the cooling tower, it is sent back to its original location by the circulating water cooling pump. The circulating water of the first condenser is fed into the cooling tower. After being cooled by the cooling tower, it is sent back to the second condenser by the circulating water cooling pump 56, and then back to the first condenser from the second condenser.

[0016] This utility model includes an ammonia tank, an ammonium fluoride reaction tank, a silica washing water storage tank, a process water storage tank, an evaporation condensate storage tank, an ammonium fluoride solution storage tank, a 50% hydrofluoric acid storage tank, a first ammonium hydrogen fluoride reaction tank, a second ammonium hydrogen fluoride reaction tank, a first-effect separator, a second-effect separator, a filter mother liquor tank, a drying tail gas scrubbing tower, a vacuum unit, a sealed water tank, a second-stage tail gas absorption tower, a cold water tank, a cooling tower, and a thickener through which process water is introduced.

[0017] Compressed air is introduced into the ammonium fluoride reaction vessel, the silica drying device, the first ammonium hydrogen fluoride reaction vessel, the second ammonium hydrogen fluoride reaction vessel, the drying dust collector, the thickener, and the silica filter press of this utility model.

[0018] This utility model introduces live steam for heating in its single-effect evaporator, double-effect evaporator, air heater, and thickener.

[0019] This invention has the following advantages over the prior art:

[0020] 1. This device adopts a process route combining evaporation concentration and cooling crystallization to treat the waste acid. The process is mature, stable, simple to operate, has reasonable operating costs, and low overall investment. The evaporation concentration system adopts double-effect evaporation concentration, which increases the total heat transfer temperature difference and has a high heat utilization rate. The evaporation concentration material flow adopts a parallel feed method for evaporation concentration operation, which conforms to the physical properties and has low heat loss. The evaporator adopts forced circulation evaporation, and the material flow rate in the heat exchange tube is high, which enhances heat transfer while reducing the tendency of material scaling.

[0021] 2. This device is equipped with secondary steam to preheat the system feed, making comprehensive use of heat and saving energy and reducing consumption.

[0022] 3. This device adopts a first-stage acid washing and a second-stage alkaline washing to ensure better washing treatment results. Attached Figure Description

[0023] Figures 1-4 This is a structural schematic diagram of one embodiment of the present invention.

[0024] In the diagram: 1. Ammonia tank; 2. Ammonia pump; 3. Ammonium fluoride reaction tank; 4. Crude ammonium fluoride solution filtration pump; 5. Silica washing liquid pump; 6. Silica washing water storage tank; 7. Silica drying tank; 8. Process water storage tank; 9. Silica washing water pump; 10. Evaporation condensate storage tank; 11. Ammonium fluoride solution storage tank; 12. Ammonium fluoride solution feed pump; 13. 50% hydrofluoric acid storage tank; 14. Hydrofluoric acid feed pump; 15. First ammonium fluoride reaction tank; 16. Second ammonium fluoride reaction tank. 17. Ammonium fluoride solution feed pump; 18. Steam condensate pump; 19. Steam condensate tank; 20. Steam condensate cooler; 21. First-effect evaporator; 22. First-effect circulating pump; 23. First-effect separator; 24. First-effect crystal slurry pump; 25. Second-effect evaporator; 26. Second-effect circulating pump; 27. Second-effect separator; 28. Second-effect crystal slurry pump; 29. ​​Filtration mother liquor pump; 30. Filtration mother liquor tank; 31. Filtration silo; 32. Filter press; 33. Drying feed conveyor 34. Vibrating fluidized bed dryer; 35. Air heater; 36. Drying blower; 37. Packaging conveyor; 38. Metering packaging machine; 39. Drying dust collector; 40. Drying exhaust gas scrubbing cooler; 41. Drying scrubbing circulating pump; 42. Drying exhaust gas scrubbing tower; 43. Drying induced draft fan; 44. Evaporation condensate tank; 45. Evaporation condensate pump; 46. Vacuum unit; 47. Sealed water tank; 48. Sealed water pump; 49. Primary exhaust gas absorption tower; 50. 51. Primary tail gas absorption circulation pump; 52. Secondary tail gas absorption tower; 53. Secondary tail gas absorption circulation pump; 54. Cold water tank; 55. Cold water circulation pump; 56. Chiller; 57. Circulating cooling water pump; 58. Cooling tower; 59. Tail gas induced draft fan; 60. Secondary condenser; 61. Primary condenser; 62. Thickener; 63. First-effect hydrocyclone; 64. Second-effect hydrocyclone; 65. Ammonia metering tank; 66. Steam saturator; 67. Silica filter press; 68. Feed trough. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to these embodiments.

[0026] Example 1

[0027] exist Figures 1-4 The present invention relates to an apparatus for producing ammonium fluoride and ammonium bifluoride using ammonium fluorosilicate, comprising an ammonium fluoride reaction unit, a silica drying unit, an ammonium bifluoride reaction unit, a fluoride salt solution concentration unit, a drying unit, a tail gas treatment unit, and a sealing unit.

[0028] The ammonium fluoride reaction unit is as follows: solid ammonium fluorosilicate is added to the ammonium fluoride reaction tank 3 from the feed tank 67; ammonia water pump 2 pumps ammonia water from ammonia water tank 1 into the ammonium fluoride reaction tank 3; the ammonium fluoride reaction tank 3 is connected to the ammonium fluoride reaction tank 3 and the silica filter press 66 respectively through the crude ammonium fluoride liquid filtration pump 4 installed on the pipeline; the outlet of the silica filter press 66 is connected to the silica drying unit; one outlet of the silica filter press 66 is connected to the ammonium fluoride reaction tank 3, one outlet is connected to the silica washing water storage tank 6, and one outlet is connected to the ammonium fluoride solution storage tank 11; the silica washing water storage tank 6 is connected to the silica washing water storage tank 6 and the ammonium fluoride reaction tank 3 through the silica washing liquid pump 5 installed on the pipeline; the evaporation condensate storage tank 10 and the process water storage tank 8 are connected to the silica filter press 66 through the silica washing water pump.

[0029] The aforementioned silica drying unit is a silica drying device 7;

[0030] The ammonium bifluoride reaction unit is as follows: an ammonium fluoride solution storage tank 11 is connected to a first ammonium bifluoride reaction tank 15 and a second ammonium bifluoride reaction tank 16 via an ammonium fluoride liquid feed pump 12 installed on a pipeline; a 50% hydrofluoric acid storage tank 13 is connected to the first ammonium bifluoride reaction tank 15 and the second ammonium bifluoride reaction tank 16 via a hydrofluoric acid feed pump 14 installed on a pipeline; the outlets of the first ammonium bifluoride reaction tank 15 and the second ammonium bifluoride reaction tank 16 are connected to the first ammonium bifluoride reaction tank 15 and the second ammonium bifluoride reaction tank 16 via an ammonium fluoride liquid feed pump 17 installed on a pipeline, and connected to a fluoride salt solution concentration unit via another route.

[0031] The fluoride salt concentration unit is as follows: the ammonium fluoride solution in the ammonium fluoride solution storage tank 11 is connected to the first-effect evaporator 21 and the second-effect evaporator 25 via an ammonium fluoride solution feed pump 12 installed on a pipeline; the ammonium bifluoride reaction tank is connected to the first-effect evaporator 21 and the second-effect evaporator 25 via an ammonium bifluoride solution feed pump 17 installed on a pipeline; the top outlet of the first-effect evaporator 21 is connected to the first-effect separator 23, and the lower outlet is connected to the steam condensate tank 19; the top outlet of the steam condensate tank 19 is connected to the steam condensate cooler 20 in one path and to the first-effect separator 23 and the second-effect evaporator 25 in the other path; the lower part of the steam condensate tank 19 is connected to the steam saturator 65 via a steam condensate pump 18 installed on a pipeline. One path connects to the steam condensate tank 19, and the other path connects to the steam condensate storage tank. The bottom outlet of the first-effect separator 23 is connected to the inlet of the first-effect hydrocyclone 62 via the first-effect slurry pump 24 installed on the pipeline. The middle outlet is connected to the first-effect evaporator 21 via the first-effect circulation pump 22 installed on the pipeline. The top outlet of the first-effect hydrocyclone 62 is connected to the first-effect separator 23. The top outlet of the second-effect evaporator 25 is connected to the second-effect separator 27, and the lower outlet is connected to the steam condensate tank 19. The top outlet of the second-effect separator 27 is connected to the first condenser 60. The middle outlet is connected to the second-effect evaporator 25 via the second-effect circulation pump 26 installed on the pipeline. The bottom outlet is connected to the second-effect slurry pump installed on the pipeline. 28 is connected to the inlet of the second-effect hydrocyclone 63. The top outlet of the second-effect hydrocyclone 63 is connected to the second-effect separator 27. The bottom outlets of the first-effect hydrocyclone 62 and the second-effect hydrocyclone 63 are both connected to the thickener 61. Ammonia water in the ammonia water tank 1 is pumped into the ammonia water metering tank 64 through the ammonia water pump 2. The ammonia water metering tank 64 is connected to the thickener 61. The outlet of the thickener 61 is connected to the filter 32. The filter 32 and the thickener 61 are both connected to the filter mother liquor tank 30. The filter mother liquor tank 30 is connected to the second-effect separator 27 through the filter mother liquor pump 29 installed on the pipeline. The filter hopper of the filter 32 is set to correspond to the drying feed conveyor 33. The drying feed conveyor 33 sends the material into the vibrating fluidized bed dryer 34. The air heater 35 utilizes... The cold air supplied by the drying blower 36 is heated by the introduced live steam. The heated air is then sent to the vibrating fluidized bed dryer 34. A packaging feeding conveyor 37 is installed at the outlet of the vibrating fluidized bed dryer 34, and a metering packaging machine 38 is installed at the outlet of the packaging feeding conveyor 37. The evaporation condensate from the double-effect evaporator 25 enters the first condenser 60. The first condenser 60 is connected to the second condenser 59 and the evaporation condensate tank 44. The evaporation condensate tank 44 is connected to the evaporation condensate storage tank through the evaporation condensate pump 45 installed on the pipeline. The non-condensable gas discharged from the second condenser 59 enters the vacuum unit 46. The wastewater from the vacuum unit 46 is discharged to the silica washing water storage tank 6.

[0032] The exhaust gas treatment unit consists of: non-condensable gas from the vibrating fluidized bed dryer 34 is discharged into the dryer dust collector 39; non-condensable gas discharged from the dryer dust collector 39 is fed into the dry exhaust gas scrubbing tower 42; the lower outlet of the dry exhaust gas scrubbing tower 42 is connected to the upper part of the dry exhaust gas scrubbing tower 42 via a dry scrubbing circulation pump 41 installed on a pipeline, and the other part is connected to the dry exhaust gas scrubbing cooler 40; the top outlet of the dry exhaust gas scrubbing tower 42 is connected to the first-stage exhaust gas absorption tower 49 via a dryer induced draft fan 43; the dry exhaust gas scrubbing cooler 40 is connected to the dry exhaust gas scrubbing tower 42; and the unit includes an ammonia tank 1, an ammonium fluoride reaction tank 3, a silica washing water storage tank 6, an evaporation condensate storage tank 10, an ammonium fluoride solution storage tank 11, a 50% hydrofluoric acid storage tank 13, and a first ammonium hydrogen fluoride reaction tank 15. The system includes a second ammonium bifluoride reaction tank 16, a filter 32, a mother liquor filter tank 30, a vibrating fluidized bed dryer 34, a vacuum unit 46, a sealed water tank 47, a thickener 61, and an ammonia metering tank 64. Non-condensable gas is introduced into the primary tail gas absorption tower 49 via a tail gas induced draft fan 58. The lower outlet of the primary tail gas absorption tower 49 is connected to the middle and upper parts of the primary tail gas absorption tower 49 via a primary tail gas absorption circulation pump 50 installed on a pipeline, and the top is connected to the secondary tail gas absorption tower 51. The lower part of the secondary tail gas absorption tower 51 is connected to the primary tail gas absorption tower 49 via a secondary tail gas absorption circulation pump 52 installed on a pipeline, and the other is connected to the middle and upper parts of the secondary tail gas absorption tower 51. The remaining tail gas in the secondary tail gas absorption tower 51 then enters the alkaline washing tower for further absorption.

[0033] The sealing unit is as follows: mechanical seal return water from each pump enters the sealing water tank 47 for cooling, and the cooled mechanical seal water is pumped back to the mechanical seal water inlet of each pump or to the silica washing water storage tank 6 via the sealing water pump 48.

[0034] In this embodiment, the outlet of the thickener 61 is connected to the cold water tank 53. The cold water tank 53 is connected to the chiller 55 via a cold water circulation pump 54 installed on a pipeline. The chiller 55 is connected to the thickener 61. The circulating water from the steam condensate cooler 20, the dry exhaust gas scrubbing cooler 40, the vacuum unit 46, the sealed water tank 47, and the chiller 55 is fed into the cooling tower 57. After being cooled by the cooling tower 57, the water is returned to its original location by the circulating water cooling pump 56. The circulating water from the first condenser 60 is fed into the cooling tower 57. After being cooled by the cooling tower 57, the water is returned to the second condenser 59 by the circulating water cooling pump 56, and then returns to the first condenser 60 from the second condenser 59. Ammonia tank 1, ammonium fluoride reaction tank 3, silica washing water storage tank 6, process water storage tank 8, evaporation condensate storage tank 10, ammonium fluoride solution storage tank 11, 50% hydrofluoric acid storage tank 13, first ammonium fluoride reaction tank 15, second ammonium fluoride reaction tank 16, first-effect separator 23, second-effect separator 27, filter mother liquor tank 30, drying tail gas scrubbing tower 42, vacuum unit 46, sealed water tank 47, secondary tail gas absorption tower 51, cold water tank 53, cooling tower 57, and process water is introduced into thickener 61. Compressed air is introduced into ammonium fluoride reaction tank 3, silica drying unit 7, first ammonium fluoride reaction tank 15, second ammonium fluoride reaction tank 16, drying dust collector 39, thickener 61, and silica filter press 66. Live steam is introduced into first-effect evaporator 21, second-effect evaporator 25, air heater 35, and thickener 61 for heating.

[0035] The working principle of this utility model is as follows:

[0036] 1) Material flow:

[0037] a. Silica products

[0038] Solid ammonium fluorosilicate is added to the ammonium fluoride reaction tank 3 from the feed trough 67 using an electric hoist and dissolved in water. Ammonia water pump 2 pumps ammonia water from ammonia water tank 1 into the ammonium fluoride reaction tank 3, where it reacts to produce ammonium fluoride and silicon dioxide. After filtration by the silica filter press 66, the silicon dioxide enters the silica drying device 7 for drying, and the product silica is obtained. The mother liquor from the filter press enters the ammonium fluoride solution storage tank 11.

[0039] b. Ammonium fluoride products

[0040] The ammonium fluoride solution is concentrated in the first and second effect evaporators. After being cooled by the thickener 61, the material enters the filter 32 for dehydration to obtain wet salt. After being dried by the drying device, the ammonium fluoride product is obtained.

[0041] c. Ammonium bifluoride

[0042] The ammonium fluoride in the ammonium fluoride solution storage tank 11 is transferred to the ammonium bifluoride reaction tank via the ammonium fluoride liquid feed pump 12. Then, the hydrofluoric acid in the 50% hydrofluoric acid storage tank 13 is added to the ammonium bifluoride reaction tank via the hydrofluoric acid feed pump 14 to react with the ammonium fluoride to generate ammonium bifluoride.

[0043] Ammonium bifluoride is concentrated in the first and second effect evaporators, cooled by the thickener 61, and then dehydrated by the filter 32 to obtain wet salt. After drying by the drying device, the ammonium bifluoride product is obtained.

[0044] d. Purification of fluorosilicic acid according to

[0045] Solid ammonium fluorosilicate is added to the ammonium fluoride reaction tank from the feed trough 67 using an electric hoist and dissolved in water. The dissolved ammonium fluorosilicate is filtered through a silica filter press 66 to remove impurities, and then the clean ammonium fluorosilicate is concentrated in a first-effect and a second-effect evaporator. After being cooled by a thickener 61, the material enters a filter press 32 for dehydration to obtain wet salt, which is then dried by a drying device to obtain the ammonium fluorosilicate product.

[0046] 2) Steam process:

[0047] Raw steam from the outside is sprayed into the material in the shell side of the first-effect evaporator 21 through the steam saturator 65. The heated material undergoes flash evaporation and vapor-liquid separation in the first-effect separator 23. The generated secondary steam enters the material in the shell side of the second-effect evaporator 25 through the second-effect separator 27. The generated secondary steam is condensed in the tube side of the condenser.

[0048] Raw steam from the outside can also be directly introduced into the material in the shell side heating tube side of the double-effect evaporator.

[0049] Part of the live steam is used to purge the bottom pipe of the thickener 61, and the other part of the live steam enters the air heater 35 to heat the cold air sent by the drying blower 36.

[0050] 3) Condensate flow:

[0051] a. Steam condensate flow

[0052] The steam condensate from the shell side of the first-effect evaporator 21, the second-effect evaporator 25, and the air heater 35 flows to the steam condensate tank by pressure difference, and is finally pumped out or reused by the steam condensate pump.

[0053] b. Evaporation and Condensation Process

[0054] The evaporative condensate from the shell side of the double-effect evaporator 25 flows to the evaporative condensate tank 44 by pressure difference, and the evaporative condensate produced by the condenser also flows to the evaporative condensate tank 44.

[0055] 4) Vacuum system and exhaust gas process:

[0056] a. Vacuum system:

[0057] The vacuum system consists of a condenser, an evaporative condensate tank 44, and a vacuum unit 46. Secondary steam generated in the double-effect separator 27 enters the tube side of the condenser for condensation. The resulting evaporative condensate and non-condensable gases flow into the evaporative condensate tank. The non-condensable gases are extracted from the second condenser 59 by the vacuum unit 46, undergo gas-liquid separation in the vacuum unit 46's water tank, and are then discharged into the tail gas collection pipeline. Simultaneously, the vacuum pump maintains the required vacuum level for the entire evaporation and concentration system.

[0058] b. Exhaust system:

[0059] The exhaust gas from the vacuum unit 46 and other equipment outlets is collected through pipelines and then enters the primary exhaust gas absorption tower 49. In the primary exhaust gas absorption tower 49, the exhaust gas flows from bottom to top, and the absorbent flows from the top of the tower to bottom. Through countercurrent exchange with the exhaust gas, the exhaust gas in the tower is absorbed multiple times. Finally, a small amount of exhaust gas enters the secondary exhaust gas absorption tower 51 for further absorption.

[0060] The tail gas entering the secondary tail gas absorption tower 51 flows from bottom to top. The absorbent liquid is pumped to the top of the tower by the secondary tail gas absorption tower circulation pump 52 and flows down. It is absorbed through multiple cycles of countercurrent exchange with the tail gas. Finally, a small amount of tail gas enters the alkaline washing tower for further absorption.

[0061] The exhaust gas from the drying equipment first enters the exhaust gas scrubbing tower 42. In the exhaust gas scrubbing tower 42, the exhaust gas flows from bottom to top, and the absorbent flows from the top of the tower downwards. Through countercurrent exchange with the exhaust gas, the exhaust gas in the tower is absorbed multiple times. Finally, a small amount of exhaust gas enters the primary and secondary exhaust gas absorption towers for scrubbing and absorption.

Claims

1. An apparatus for producing ammonium fluoride and ammonium bifluoride using ammonium fluorosilicate, characterized in that: It includes an ammonium fluoride reaction unit, a silica drying unit, an ammonium bifluoride reaction unit, a fluoride salt solution concentration unit, a drying unit, a tail gas treatment unit, and a sealing unit; The ammonium fluoride reaction unit is as follows: solid ammonium fluorosilicate is added to the ammonium fluoride reaction tank (3) from the feed tank (67), and the ammonia water pump (2) pumps the ammonia water in the ammonia water tank (1) into the ammonium fluoride reaction tank (3). The ammonium fluoride reaction tank (3) is connected to the ammonium fluoride reaction tank (3) and the silica filter press (66) respectively through the crude ammonium fluoride liquid filter pump (4) installed on the pipeline. The outlet of the silica filter press (66) is connected to the silica drying unit. (66) One outlet is connected to the ammonium fluoride reaction tank (3), one outlet is connected to the silica washing water storage tank (6), and one outlet is connected to the ammonium fluoride solution storage tank (11). The silica washing water storage tank (6) is connected to the silica washing water storage tank (6) and the ammonium fluoride reaction tank (3) through the silica washing liquid pump (5) installed on the pipeline. The evaporation condensate storage tank (10) and the process water storage tank (8) are connected to the silica filter press (66) through the silica washing water pump. The aforementioned silica drying unit is a silica drying device (7); The ammonium fluoride reaction unit is as follows: an ammonium fluoride solution storage tank (11) is connected to the first ammonium fluoride reaction tank (15) and the second ammonium fluoride reaction tank (16) respectively through an ammonium fluoride liquid feed pump (12) installed on the pipeline; a 50% hydrofluoric acid storage tank (13) is connected to the first ammonium fluoride reaction tank (15) and the second ammonium fluoride reaction tank (16) through a hydrofluoric acid feed pump (14) installed on the pipeline; the outlets of the first ammonium fluoride reaction tank (15) and the second ammonium fluoride reaction tank (16) are connected to the first ammonium fluoride reaction tank (15) and the second ammonium fluoride reaction tank (16) through an ammonium fluoride liquid feed pump (17) installed on the pipeline, and connected to the fluoride salt solution concentration unit in one direction. The fluoride salt concentration unit is as follows: the ammonium fluoride solution in the ammonium fluoride solution storage tank (11) is connected to the first-effect evaporator (21) and the second-effect evaporator (25) through the ammonium fluoride solution feed pump (12) installed on the pipeline; the ammonium fluoride reaction tank is connected to the first-effect evaporator (21) and the second-effect evaporator (25) through the ammonium fluoride solution feed pump (17) installed on the pipeline; the top outlet of the first-effect evaporator (21) is connected to the first-effect separator (23), and the bottom outlet is connected to the steam condensate tank (19); the top outlet of the steam condensate tank (19) is connected to the steam condensate cooler (20) in one way and to the first-effect separator (23) and the second-effect evaporator (25) in the other way; the steam condensate tank (19)... The lower part is connected to the steam saturator (65), the steam condensate tank (19), and the steam condensate storage tank via a steam condensate pump (18) installed on the pipeline. The bottom outlet of the first-effect separator (23) is connected to the inlet of the first-effect hydrocyclone (62) via a first-effect crystal slurry pump (24) installed on the pipeline. The middle outlet is connected to the first-effect evaporator (21) via a first-effect circulation pump (22) installed on the pipeline. The top outlet of the first-effect hydrocyclone (62) is connected to the first-effect separator (23). The top outlet of the second-effect evaporator (25) is connected to the second-effect separator (27), and the lower outlet is connected to the steam condensate tank (19). The top outlet of the second-effect separator (27) is connected to the first condensate tank. The middle outlet is connected to the second-effect evaporator (25) via a second-effect circulating pump (26) installed on the pipeline, and the bottom outlet is connected to the inlet of the second-effect hydrocyclone (63) via a second-effect crystal slurry pump (28) installed on the pipeline. The top outlet of the second-effect hydrocyclone (63) is connected to the second-effect separator (27). The bottom outlets of the first-effect hydrocyclone (62) and the second-effect hydrocyclone (63) are both connected to the thickener (61). The ammonia water in the ammonia water tank (1) is fed into the ammonia water metering tank (64) via the ammonia water pump (2). The ammonia water metering tank (64) is connected to the thickener (61). The outlet of the thickener (61) is connected to the filter (32). The filter (32) and the thickener (61) are both connected to the mother liquor tank (30). The filter mother liquor tank (30) is connected to the second-effect separator (27) through the filter mother liquor pump (29) installed on the pipeline. The filter hopper of the filter machine (32) is set up with the drying feed conveyor (33). The drying feed conveyor (33) sends the material into the vibrating fluidized bed dryer (34). The air heater (35) uses the introduced live steam to heat the cold air sent by the drying blower (36). The heated air is sent into the vibrating fluidized bed dryer (34). The outlet of the vibrating fluidized bed dryer (34) is set up with the packaging feed conveyor (37). The outlet of the packaging feed conveyor (37) is set up with the metering packaging machine (38). The evaporation condensate from the second-effect evaporator (25) enters the first condenser (60).The first condenser (60) is connected to the second condenser (59) and the evaporative condensate tank (44). The second condenser (59) is connected to the evaporative condensate tank (44). The evaporative condensate tank (44) is connected to the evaporative condensate storage tank via an evaporative condensate pump (45) installed on a pipeline. The non-condensable gas discharged from the second condenser (59) enters the vacuum unit (46). The wastewater from the vacuum unit (46) is discharged to the silica washing water storage tank (6). The exhaust gas treatment unit is as follows: the non-condensable gas from the vibrating fluidized bed dryer (34) is discharged into the dryer dust collector (39), and the non-condensable gas discharged from the dryer dust collector (39) is fed into the dry exhaust gas scrubbing tower (42). The lower outlet of the dry exhaust gas scrubbing tower (42) is connected to the upper part of the dry exhaust gas scrubbing tower (42) through a dry scrubbing circulation pump (41) installed on the pipeline, and the other part is connected to the dry exhaust gas scrubbing cooler (40). The top outlet of the dry exhaust gas scrubbing tower (42) is connected to the first-stage exhaust gas absorption tower (49) through a dryer induced draft fan (43). The dry exhaust gas scrubbing cooler (40) is connected to the dry exhaust gas scrubbing tower (42). The unit includes an ammonia tank (1), an ammonium fluoride reaction tank (3), a silica washing water storage tank (6), an evaporation condensate storage tank (10), an ammonium fluoride solution storage tank (11), a 50% hydrofluoric acid storage tank (13), and a first ammonium hydrogen fluoride reaction tank (15). The non-condensable gas is introduced into the first-stage tail gas absorption tower (49) by the tail gas induced draft fan (58) through the tail gas induced draft fan (58). The lower outlet of the first-stage tail gas absorption tower (49) is connected to the middle and upper parts of the first-stage tail gas absorption tower (49) through the first-stage tail gas absorption circulation pump (50) installed on the pipeline, and the top is connected to the second-stage tail gas absorption tower (51). The lower part of the second-stage tail gas absorption tower (51) is connected to the first-stage tail gas absorption tower (49) through the second-stage tail gas absorption circulation pump (52) installed on the pipeline, and the other part is connected to the middle and upper parts of the second-stage tail gas absorption tower (51). The remaining tail gas of the second-stage tail gas absorption tower (51) is then sent to the alkaline washing tower for absorption. The sealing unit is as follows: mechanical seal return water from each pump enters the sealing water tank (47) for cooling, and the cooled mechanical seal water is pumped back to the mechanical seal water inlet of each pump or to the silica washing water storage tank (6) through the sealing water pump (48).

2. The apparatus for producing ammonium fluoride and ammonium bifluoride from ammonium fluorosilicate according to claim 1, characterized in that: The outlet of the thickener (61) is connected to the cold water tank (53), the cold water tank (53) is connected to the chiller (55) through the cold water circulation pump (54) installed on the pipeline, and the chiller (55) is connected to the thickener (61).

3. The apparatus for producing ammonium fluoride and ammonium bifluoride from ammonium fluorosilicate according to claim 1, characterized in that: The circulating water from the steam condensate cooler (20), the dry exhaust gas scrubbing cooler (40), the vacuum unit (46), the sealed water tank (47), and the refrigeration unit (55) is fed into the cooling tower (57), cooled by the cooling tower (57), and then sent back to its original location by the circulating water cooling pump (56); the circulating water from the first condenser (60) is fed into the cooling tower (57), cooled by the cooling tower (57), and then sent back to the second condenser (59) by the circulating water cooling pump (56), and then returned to the first condenser (60) from the second condenser (59).

4. The apparatus for producing ammonium fluoride and ammonium bifluoride from ammonium fluorosilicate according to claim 1, characterized in that: Process water is introduced into the ammonia tank (1), ammonium fluoride reaction tank (3), silica washing water storage tank (6), process water storage tank (8), evaporation condensate storage tank (10), ammonium fluoride solution storage tank (11), 50% hydrofluoric acid storage tank (13), first ammonium fluoride reaction tank (15), second ammonium fluoride reaction tank (16), first-effect separator (23), second-effect separator (27), mother liquor filter tank (30), dry tail gas scrubbing tower (42), vacuum unit (46), sealed water tank (47), secondary tail gas absorption tower (51), cold water tank (53), cooling tower (57), and thickener (61).

5. The apparatus for producing ammonium fluoride and ammonium bifluoride from ammonium fluorosilicate according to claim 1, characterized in that: Compressed air is introduced into the ammonium fluoride reaction tank (3), the silica drying device (7), the first ammonium hydrogen fluoride reaction tank (15), the second ammonium hydrogen fluoride reaction tank (16), the dryer and dust collector (39), the thickener (61), and the silica filter press (66).

6. The apparatus for producing ammonium fluoride and ammonium bifluoride from ammonium fluorosilicate according to claim 1, characterized in that: Live steam is introduced into the first-effect evaporator (21), the second-effect evaporator (25), the air heater (35), and the thickener (61) for heating.

Images