Crystallizing agent preparation system based on ammonium diuranate precipitate mother liquor

Abstract

The crystallizing agent preparation system based on ammonium diuranate precipitation mother liquor comprises a solid-liquid separation assembly, an ammonia removal assembly, a carbonization synthesis assembly and a storage tank assembly; the solid-liquid separation assembly comprises a thickener, a plate-and-frame filter press and a static pressure filter; the ammonia removal assembly comprises a stripping tower, a water vapor generating device, a condenser, a three-way valve A, a three-way valve B and a three-way valve C; the carbonization synthesis assembly comprises a filler tower A, a Venturi mixer, a carbon dioxide vaporizer, a liquid carbon dioxide storage tank and a three-way valve D; and the storage tank assembly comprises an ammonium diuranate precipitation mother liquor storage tank, an alkali liquor storage tank, an ammonia water storage tank and an ammonium carbonate solution storage tank. The application is aimed at recycling the ammonium diuranate precipitation mother liquor in the uranium purification process route, converting the fixed ammonia into free ammonia, preparing ammonia water, synthesizing the ammonia water with carbon dioxide to prepare ammonium carbonate solution, and returning the ammonium carbonate solution to the uranium purification process route as a crystallizing agent, thereby reducing the production cost of uranium purification.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of natural uranium purification technology in nuclear industry, and particularly to a crystallization agent preparation system based on ammonium diuranate precipitation mother liquor. BACKGROUND

[0002] Natural uranium purification production (from yellow cake to nuclear pure UO2) is the front end of nuclear fuel production and plays an important role in the atomic energy industry. The process route of uranium purification includes the following steps: 1. yellow cake is reacted with nitric acid to prepare uranyl nitrate (UNH) containing high impurities; 2. uranyl nitrate (UNH) is extracted by TBP-sulfonated kerosene, and micro-nitric acid is back-extracted to obtain nuclear pure uranyl nitrate (UNH); 3. uranyl nitrate (UNH) is reacted with ammonium hydroxide (NH4OH) to prepare ammonium diuranate (ADU); 4. ammonium diuranate (ADU) is reacted with ammonium carbonate ((NH4)2CO3) to prepare uranyl ammonium tricarbonate (AUC); 5. uranyl ammonium tricarbonate (AUC) is filtered and calcined to prepare nuclear pure UO2.

[0003] In the above process route, the process of precipitating uranyl nitrate with ammonia water to prepare ammonium diuranate (corresponding to the third sub-step above) has been used since the late 1950s, and its chemical reaction formula is: UO2(NO3)2+ NH4OH→ (NH4)2U2O7↓+ NH4NO3; the precipitate mother liquor generated in the reaction contains Plasma, it is appropriate to recycle and reduce resource waste.

[0004] At present, the recovery method for the above-mentioned precipitate mother liquor is mainly used for recovering nitrate and ammonium therein, and the specific steps are as follows:

[0005] 1. First, concentrated sulfuric acid is added to the precipitate mother liquor to convert nitrate to nitric acid, and then the solution after heating reaction is used to convert nitric acid to nitric acid vapor. Finally, the concentrated nitric acid obtained by condensing the collected nitric acid is obtained, i.e. the recovery of nitrate is realized, and its chemical reaction formula is: NH4NO3+ H2SO4→ HNO3↑+ NH4HSO4;

[0006] 2. Lime milk is added to the ammonium bisulfate solution obtained in the above step to convert the fixed-state ammonium to free-state ammonium, and then heating is performed to convert the free ammonium to gaseous ammonia. Finally, the gaseous ammonia obtained by condensing the collected gaseous ammonia is obtained, i.e. the recovery of ammonium is realized, and its chemical reaction formula is: NH4HSO4+ Ca(OH)2→ NH3↑+ 2H2O↑+ CaSO4↓.

[0007] The above-mentioned recovery method for the precipitation mother liquor has the following deficiencies in practical application: the addition of concentrated sulfuric acid introduces sulfate ions, changes the nitrate ion system solution into a sulfate ion system solution, and then the addition of lime milk causes the sulfate ions to combine with calcium ions to form calcium sulfate precipitate, which is equivalent to producing a new byproduct (calcium sulfate precipitate) while recovering the nitrate ions and ammonium ions; since the precipitation mother liquor itself contains radioactive uranium elements, the calcium sulfate precipitate generated in the reaction will inevitably contain radioactive uranium elements, and the calcium sulfate precipitate containing radioactive uranium elements cannot be sold commercially or further decontaminated. SUMMARY

[0008] The purpose of the present application is to overcome the deficiencies of the prior art and provide a crystallizing agent preparation system based on ammonium diuranate precipitation mother liquor, which solves the problem that the current recovery method for ammonium diuranate precipitation mother liquor produces difficult-to-handle byproducts.

[0009] The technical scheme of the present application is: a crystallizing agent preparation system based on ammonium diuranate precipitation mother liquor, comprising a solid-liquid separation assembly, an ammonia removal assembly, a carbon synthesis assembly, and a storage tank assembly;

[0010] The solid-liquid separation assembly comprises a thickener, a plate-and-frame filter press, and a static pressure filter; the overflow filtrate of the thickener is communicated with the plate-and-frame filter press, and the filtrate discharged by the plate-and-frame filter press is communicated with the static pressure filter;

[0011] The deamination assembly comprises a stripping tower, a steam generator, a condenser, a three-way valve A, a three-way valve B and a three-way valve C; the stripping tower is internally provided with, from bottom to top, a tower kettle liquid cavity, a gas-liquid mass transfer cavity and an ammonia gas cavity; the stripping tower top is provided with an ammonia gas outlet connected to the ammonia gas cavity; the stripping tower bottom is provided with a tower kettle liquid outlet connected to the tower kettle liquid cavity; the stripping tower side wall is provided with a steam inlet connected to the junction of the tower kettle liquid cavity and the gas-liquid mass transfer cavity; the stripping tower side wall is provided with a tower kettle liquid backflow port connected to the junction of the tower kettle liquid cavity and the gas-liquid mass transfer cavity; the stripping tower side wall is provided with an ammonia water backflow port connected to the junction of the gas-liquid mass transfer cavity and the ammonia gas cavity; the stripping tower side wall is provided with a mother liquor lye inlet connected to the gas-liquid mass transfer cavity; the steam generator is connected to the steam inlet of the stripping tower; the condenser is provided with a gas phase inlet, a liquid phase outlet and a non-condensable gas outlet; the gas phase inlet of the condenser is connected to the ammonia gas outlet of the stripping tower; the three-way valve A is provided with a first port, a second port and a third port; the first port of the three-way valve A is connected to the liquid phase outlet of the condenser; the second port of the three-way valve A is connected to the ammonia water backflow port of the stripping tower; the third port of the three-way valve A is used for outputting ammonia water; the three-way valve B is provided with a fourth port, a fifth port and a sixth port; the fourth port of the three-way valve B is connected to the mother liquor lye inlet of the stripping tower; the fifth port of the three-way valve B is used for receiving lye; the sixth port of the three-way valve B is used for receiving mother liquor; the three-way valve C is provided with a seventh port, an eighth port and a ninth port; the seventh port of the three-way valve C is connected to the tower kettle liquid outlet of the stripping tower; the eighth port of the three-way valve C is connected to the tower kettle liquid backflow port of the stripping tower; the ninth port of the three-way valve C is used for discharging tower kettle liquid;

[0012] The carbon synthesis assembly comprises a packed tower A, a Venturi mixer, a carbon dioxide vaporizer, a liquid carbon dioxide storage tank and a three-way valve D; the packed tower A is internally provided with, from bottom to top, a bottom liquid cavity, a carbon synthesis cavity and a tail gas cavity; the packed tower A is internally provided with a water spraying component at the junction of the carbon synthesis cavity and the tail gas cavity; the water spraying component is used for spraying water mist into the carbon synthesis cavity; the packed tower A side wall is provided with a deionized water inlet connected to the water spraying component; the packed tower A top is provided with a tail gas outlet connected to the tail gas cavity; the packed tower A bottom is provided with a bottom liquid outlet connected to the bottom liquid cavity; the packed tower A side wall is provided with a gas-liquid mixing inlet connected to the junction of the bottom liquid cavity and the carbon synthesis cavity; the packed tower A side wall is provided with an ammonia water inlet connected to the carbon synthesis cavity; the Venturi mixer upper end is provided with a solution inlet and a gas inlet; the Venturi mixer lower end is provided with a gas-liquid mixing outlet connected to the gas-liquid mixing inlet of the packed tower A; the carbon dioxide vaporizer two ends are respectively provided with a liquid inlet and a gas outlet; the liquid inlet is connected to the liquid carbon dioxide storage tank; the gas outlet is connected to the gas inlet of the Venturi mixer; the three-way valve D is provided with a tenth port, an eleventh port and a twelfth port; the tenth port of the three-way valve D is connected to the bottom liquid outlet of the packed tower A; the eleventh port of the three-way valve D is connected to the solution inlet of the Venturi mixer;

[0013] The tank assembly comprises a precipitation mother liquor tank, an alkali liquor tank, an ammonia water tank and an ammonium carbonate solution tank; the precipitation mother liquor tank is provided with a liquid inlet A and a liquid outlet A, the liquid inlet A of the precipitation mother liquor tank is communicated with the static pressure filter, the liquid outlet A of the precipitation mother liquor tank is communicated with the sixth port of the three-way valve B, the alkali liquor tank is communicated with the fifth port of the three-way valve B, the ammonia water tank is provided with a liquid inlet C and a liquid outlet C, the liquid inlet C of the ammonia water tank is communicated with the third port of the three-way valve A, the liquid outlet C of the ammonia water tank is communicated with the ammonia water inlet of the packed tower A, and the ammonium carbonate solution tank is communicated with the twelfth port of the three-way valve D.

[0014] The further technical scheme of the present application is that the thickener is internally provided with a separation chamber, an overflow port for discharging the clarified liquid in the upper part of the separation chamber is arranged on the upper end side wall of the thickener; the plate-and-frame filter press is provided with a liquid inlet D and a liquid outlet D, the liquid inlet D of the plate-and-frame filter press is communicated with the overflow port of the thickener to receive the clarified liquid discharged from the thickener; the static pressure filter is provided with a liquid inlet E and a liquid outlet E, the liquid inlet E of the static pressure filter is communicated with the liquid outlet E of the plate-and-frame filter press to receive the filtrate discharged from the plate-and-frame filter press, and the liquid outlet E of the static pressure filter is communicated with the liquid inlet A of the precipitation mother liquor tank to discharge the filtrate filtered by the static pressure filter.

[0015] The still further technical scheme of the present application is that the ammonia removal assembly further comprises a tubular heat exchanger A arranged between the precipitation mother liquor tank and the three-way valve C; the tubular heat exchanger A is provided with a shell inlet, a shell outlet, a tube inlet and a tube outlet; the shell inlet of the tubular heat exchanger A is communicated with the liquid outlet A of the precipitation mother liquor tank, the shell outlet of the tubular heat exchanger A is communicated with the sixth port of the three-way valve B, the tube inlet of the tubular heat exchanger A is communicated with the ninth port of the three-way valve C, and a pipeline for discharging column still liquid is connected to the tube outlet of the tubular heat exchanger A.

[0016] The still further technical scheme of the present application is that the carbonization and synthesis assembly further comprises a tubular heat exchanger B arranged between the bottom liquid outlet of the packed tower A and the solution inlet of the Venturi mixer; the tubular heat exchanger B is provided with a cooling water inlet, a cooling water outlet, an ammonium carbonate solution inlet and an ammonium carbonate solution outlet; the ammonium carbonate solution inlet of the tubular heat exchanger B is communicated with the bottom liquid outlet of the packed tower A, and the ammonium carbonate solution outlet of the tubular heat exchanger B is communicated with the solution inlet of the Venturi mixer.

[0017] The further technical scheme of the present application is: the tail gas treatment assembly further comprises a filler tower B and a dilute nitric acid storage tank; the filler tower B is internally provided with a liquid phase cavity, a filler absorption cavity and a gas phase cavity from bottom to top in sequence, a spraying component is arranged at the intersection of the filler absorption cavity and the gas phase cavity in the filler tower B, the spraying component is used for spraying misty dilute nitric acid into the filler absorption cavity, a non-condensable gas outlet is arranged at the top of the filler tower B and connected to the gas phase cavity, a dilute nitric acid inlet is arranged on the side wall of the filler tower B and connected to the spraying component, a non-condensable gas inlet is arranged on the side wall of the filler tower B and connected to the intersection of the liquid phase cavity and the filler absorption cavity, a tail gas inlet is arranged on the side wall of the filler tower B and connected to the intersection of the liquid phase cavity and the filler absorption cavity, and an ammonium nitrate solution outlet is arranged at the bottom of the filler tower B and connected to the liquid phase cavity; the non-condensable gas inlet of the filler tower B is connected to the non-condensable gas outlet of the condenser, and the tail gas inlet of the filler tower B is connected to the tail gas outlet of the filler tower A; the dilute nitric acid storage tank is connected to the dilute nitric acid inlet of the filler tower B.

[0018] The further technical scheme of the present application is: a pump A is arranged on the pipeline between the thickener and the plate-and-frame filter press, a pump B is arranged on the pipeline between the plate-and-frame filter press and the static pressure filter; a pump C is arranged on the pipeline between the second port of the three-way valve A and the ammonia water backflow port of the stripping tower, a pump D is arranged on the pipeline between the third port of the three-way valve A and the ammonia water storage tank, a pump E is arranged on the pipeline between the fourth port of the three-way valve B and the mother liquor lye inlet of the stripping tower; a pump F is arranged on the pipeline between the eighth port of the three-way valve C and the tower kettle liquid backflow port of the stripping tower; a pump G is connected to the pipeline connected to the tube side outlet of the shell-and-tube heat exchanger A, a pump H is arranged on the pipeline between the ammonium carbonate solution inlet of the shell-and-tube heat exchanger B and the bottom liquid outlet of the filler tower A, and a pump I is arranged on the pipeline between the dilute nitric acid storage tank and the dilute nitric acid inlet of the filler tower B.

[0019] The further technical scheme of the present application is: a flow control valve A is arranged on the pipeline between the water vapor generating device and the steam inlet of the stripping tower, a flow control valve B is arranged on the pipeline between the lye storage tank and the fifth port of the three-way valve B, a flow control valve C is arranged on the pipeline between the liquid outlet A of the precipitated mother liquor storage tank and the shell side inlet of the shell-and-tube heat exchanger, and a flow control valve D is arranged on the pipeline between the liquid inlet of the carbon dioxide vaporizer and the liquid carbon dioxide storage tank.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] 1. The present application is aimed at recycling the ammonium diuranate precipitated mother liquor in the uranium purification process, converting the fixed ammonia in the ammonium diuranate precipitated mother liquor into free ammonia, preparing ammonia water, and then synthesizing the ammonia water with carbon dioxide to prepare ammonium carbonate solution, which can be returned to the uranium purification process as a crystallizing agent, thereby reducing the production cost of uranium purification.

[0022] 2. The recovery process is simple, easy to operate, no difficult-to-handle precipitate is produced, by-product sodium nitrate solution produced in the recovery process can be used for further recovery of nitrate or can be discharged under the premise of meeting environmental protection requirements; the treatment mode is various and easy to implement.

[0023] The application will be further described in combination with the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Fig. 1 is a structural schematic diagram of the application;

[0025] Figure 2 Fig. 2 is a structural schematic diagram of a solid-liquid separation assembly in the application;

[0026] Figure 3 Fig. 3 is a connection relationship diagram of other assemblies in the application except the solid-liquid separation assembly;

[0027] Figure 4 Fig. 4 is an enlarged view of A part of Fig. 1; Figure 3

[0028] Figure 5 Fig. 5 is an enlarged view of B part of Fig. 1; Figure 3

[0029] Figure 6 Fig. 6 is an enlarged view of C part of Fig. 1; Figure 3

[0030] Figure 7 Fig. 7 is an enlarged view of D part of Fig. 1; Figure 3

[0031] Figure 8 Fig. 8 is an enlarged view of E part of Fig. 1. Figure 3

[0032] ​​​​​Legend: Thickener 11; Plate and frame filter press 12; Static pressure filter 13; Stripping tower 21; Reboiler liquid chamber 211; Gas-liquid mass transfer chamber 212; Ammonia chamber 213; Ammonia outlet 214; Reboiler liquid outlet 215; Steam inlet 216; Reboiler liquid reflux port 217; Ammonia water reflux port 218; Mother liquor / alkali inlet 219; Steam generator 22; Condenser 23; Gas phase inlet 231; Liquid phase outlet 232; Non-condensable gas outlet 233; First port 241; Second port 242; Third port 243; Fourth port 251; Fifth port 252; Sixth port 253; Seventh port 261; Eighth port 262; Ninth port 263; Shell and tube heat exchanger A27; Packed tower A31; Bottom liquid chamber 311; Carbonization synthesis chamber 312; Tail gas Chamber 313; Deionized water inlet 314; Tail gas outlet 315; Bottom liquid outlet 316; Gas-liquid mixing inlet 317; Ammonia inlet 318; Venturi mixer 32; Solution inlet 321; Gas inlet 322; Gas-liquid mixing outlet 323; Carbon dioxide vaporizer 33; Liquid carbon dioxide storage tank 34; Tenth port 351; Eleventh port 352; Twelfth port 353; Shell-and-tube heat exchanger B36; Precipitated mother liquor storage tank 41; Alkali storage tank 42; Ammonia storage tank 43; Ammonium carbonate solution storage tank 44; Packed tower B51; Liquid phase chamber 511; Packed absorption chamber 512; Gas phase chamber 513; Non-condensable gas outlet 514; Dilute nitric acid inlet 515; Non-condensable gas inlet 516; Tail gas inlet 517; Ammonium nitrate solution outlet 518; Dilute nitric acid storage tank 52. Detailed Implementation

[0033] Example 1:

[0034] like Figures 1-8 As shown, the crystallizer preparation system based on ammonium diuranate precipitate mother liquor includes a solid-liquid separation component, a deammoniation component, a carbonization synthesis component, a storage tank component, and a tail gas treatment component.

[0035] The solid-liquid separation assembly includes a thickener 11, a plate and frame filter press 12, and a static pressure filter 13. The thickener 11 has a separation chamber inside, and an overflow port on its upper side wall for discharging the clarified liquid from the upper part of the separation chamber. The thickener 11 also has an underflow port at its bottom for discharging the concentrated slurry from the lower part of the separation chamber. The plate and frame filter press 12 has an inlet D and an outlet D. The inlet D of the plate and frame filter press 12 is connected to the overflow port of the thickener 11 to receive the clarified liquid discharged from the thickener 11. The static pressure filter 13 has an inlet E and an outlet E. The inlet E of the static pressure filter 13 is connected to the outlet E of the plate and frame filter press 12 to receive the filtrate discharged from the plate and frame filter press 12. The outlet E of the static pressure filter 13 is used to discharge the filtrate filtered by the static pressure filter 13.

[0036] The solid-liquid separation assembly is used to remove the solid phase in the solution after reaction, wherein the filtration precision of the thickener 11, the plate-and-frame filter press 12 and the static pressure filter 13 is improved in turn, forming a three-stage filtration system from coarse to fine. The thickener 11 is used to perform solid-liquid separation on the product after the reaction of uranyl nitrate (referred to as UNH) and ammonium hydroxide (NH4OH), and most of the solid phase components in the reaction product are removed. The liquid phase component flows into the plate-and-frame filter press 12, and the solid phase is ammonium diuranate ((NH4)2U2O7). The liquid phase is the precipitate mother liquor (mainly ammonium nitrate (NH4NO3) solution). The plate-and-frame filter press 12 is used to intercept the fine crystals (mainly composed of ammonium diuranate and uranium oxide impurities) remaining in the precipitate mother liquor. The liquid phase component obtained after interception flows into the static pressure filter 13. The static pressure filter 13, also known as an open filter, is used to perform the most fine inspection filtration on the precipitate mother liquor, further filter the fine crystals (mainly composed of ammonium diuranate and uranium oxide impurities) remaining in the precipitate mother liquor, so that the final precipitate mother liquor discharged from the static pressure filter 13 has a uranium content of less than 15 mg / L, and the suspended solids ss < 200 mg / L.

[0037] The deamination assembly comprises a stripping tower 21, a steam generating device 22, a condenser 23, a three-way valve A, a three-way valve B and a three-way valve C. The stripping tower 21 is internally provided with, from bottom to top, a tower kettle liquid cavity 211, a gas-liquid mass transfer cavity 212 and an ammonia gas cavity 213 which are sequentially communicated, the stripping tower 21 is provided at the top with an ammonia gas outlet 214 which is communicated to the ammonia gas cavity 213, the stripping tower 21 is provided at the bottom with a tower kettle liquid outlet 215 which is communicated to the tower kettle liquid cavity 211, the stripping tower 21 is provided on the side wall with a steam inlet 216 which is communicated to the junction of the tower kettle liquid cavity 211 and the gas-liquid mass transfer cavity 212, the stripping tower 21 is provided on the side wall with a tower kettle liquid reflux port 217 which is communicated to the junction of the tower kettle liquid cavity 211 and the gas-liquid mass transfer cavity 212, the stripping tower 21 is provided on the side wall with an ammonia water reflux port 218 which is communicated to the junction of the gas-liquid mass transfer cavity 212 and the ammonia gas cavity 213, and the stripping tower 21 is provided on the side wall with a mother liquor lye inlet 219 which is communicated to the gas-liquid mass transfer cavity 212. The steam generating device 22 is communicated to the steam inlet 216 of the stripping tower 21. The condenser 23 is provided with a gas phase inlet 231, a liquid phase outlet 232 and a non-condensable gas outlet 233, and the gas phase inlet 231 of the condenser 23 is communicated to the ammonia gas outlet 214 of the stripping tower 21. The three-way valve A is provided with a first port 241, a second port 242 and a third port 243, the first port 241 of the three-way valve A is communicated to the liquid phase outlet 232 of the condenser 23, the second port 242 of the three-way valve A is communicated to the ammonia water reflux port 218 of the stripping tower 21, and the third port 243 of the three-way valve A is used for outputting ammonia water. The three-way valve B is provided with a fourth port 251, a fifth port 252 and a sixth port 253, the fourth port 251 of the three-way valve B is communicated to the mother liquor lye inlet 219 of the stripping tower 21, the fifth port 252 of the three-way valve B is used for receiving lye, and the sixth port 253 of the three-way valve B is used for receiving mother liquor. The three-way valve C is provided with a seventh port 261, an eighth port 262 and a ninth port 263, the seventh port 261 of the three-way valve C is communicated to the tower kettle liquid outlet 215 of the stripping tower 21, the eighth port 262 of the three-way valve C is communicated to the tower kettle liquid reflux port 217 of the stripping tower 21, and the ninth port 263 of the three-way valve C is used for discharging tower kettle liquid.

[0038] The deaminating assembly is used to convert the fixed ammonia in the precipitated mother liquor into free ammonia. On one hand, the high-temperature water vapor (100°C) produced by the water vapor generating device 22 enters the gas-liquid mass transfer cavity 212 of the stripping tower 21 through the pipeline and the vapor inlet 216, and then flows upward. On the other hand, the sodium hydroxide (NaOH) solution in the lye storage tank 32 enters the gas-liquid mass transfer cavity 212 of the stripping tower 21 through the pipeline, the fifth port 252 of the three-way valve B, the fourth port 251 of the three-way valve B, and the mother liquor lye inlet 219 of the stripping tower 21 in sequence, and then sprays downward. On the other hand, the precipitated mother liquor (NH4NO3 solution) in the precipitated mother liquor storage tank 31 enters the gas-liquid mass transfer cavity 212 of the stripping tower 21 through the pipeline, the sixth port 253 of the three-way valve B, the fourth port 251 of the three-way valve B, and the mother liquor lye inlet 219 of the stripping tower 21 in sequence, and then sprays downward. In the gas-liquid mass transfer cavity 212 of the stripping tower 21, the upward flowing water vapor and the downward spraying mixed solution (the mixed solution is obtained by mixing the sodium hydroxide solution and the precipitated mother liquor) are countercurrently contacted, gas-liquid mass transfer is carried out, and the following chemical reaction occurs: NH4NO3+ NaOH→ NaNO3+ NH4OH; The sodium nitrate solution and the ammonium hydroxide solution generated by the reaction flow downward and collect in the tower liquid cavity 211 to form the tower liquid; In the tower liquid cavity 211 of the stripping tower 21, the ammonium hydroxide is endothermically decomposed, and the following decomposition reaction occurs: NH4OH→ NH3↑+ H2O; The water produced by the decomposition remains in the tower liquid cavity 211, and the ammonia gas produced by the decomposition flows upward and is discharged to the outside of the stripping tower 21 through the gas-liquid mass transfer cavity 212, the ammonia gas cavity 213, and the ammonia gas outlet 214 in sequence. Therefore, the main component of the tower liquid is sodium nitrate, and contains a small amount of ammonium hydroxide to be decomposed. Based on the above two reactions, the fixed ammonia in the precipitated mother liquor is converted into free ammonia.

[0039] The carbonation synthesis assembly comprises a filler tower A31, a Venturi mixer 32, a carbon dioxide vaporizer 33, a liquid carbon dioxide storage tank 34, and a three-way valve D. The filler tower A31 is internally provided with, from bottom to top, a bottom liquid chamber 311, a carbonation synthesis chamber 312, and a tail gas chamber 313. The filler tower A31 is internally provided with a water spraying component at the junction of the carbonation synthesis chamber 312 and the tail gas chamber 313, which is used to spray water mist into the carbonation synthesis chamber 312. The filler tower A31 is provided with a deionized water inlet 314 on the side wall, which is connected to the water spraying component. The filler tower A31 is provided with a tail gas outlet 315 at the top, which is connected to the tail gas chamber 313. The filler tower A31 is provided with a bottom liquid outlet 316 at the bottom, which is connected to the bottom liquid chamber 311. The filler tower A31 is provided with a gas-liquid mixing inlet 317 on the side wall, which is connected to the junction of the bottom liquid chamber 311 and the carbonation synthesis chamber 312. The filler tower A31 is provided with an aqueous ammonia inlet 318 on the side wall, which is connected to the carbonation synthesis chamber 312. The Venturi mixer 32 is provided with a solution inlet 321 and a gas inlet 322 at the upper end. The Venturi mixer 32 is provided with a gas-liquid mixing outlet 323 at the lower end, which is connected to the gas-liquid mixing inlet 317 of the filler tower A31. The carbon dioxide vaporizer 33 is provided with a liquid inlet and a gas outlet at both ends. The liquid inlet is connected to the liquid carbon dioxide storage tank 34, and the gas outlet is connected to the gas inlet 322 of the Venturi mixer 32. The three-way valve D is provided with a tenth port 351, an eleventh port 352, and a twelfth port 353. The tenth port 351 of the three-way valve D is connected to the bottom liquid outlet 316 of the filler tower A31, and the eleventh port 352 of the three-way valve D is connected to the solution inlet 321 of the Venturi mixer 32.

[0040] The carbonization synthesis assembly is used for carbonization treatment of ammonia water. On one hand, the ammonia water prepared by the deamination assembly enters the carbonization synthesis cavity 312 of the packed tower A31 through the ammonia water inlet 318 of the packed tower A31, and on the other hand, the liquid carbon dioxide stored in the liquid carbon dioxide storage tank 34 is gasified through the carbon dioxide vaporizer 33, sequentially passes through the Venturi mixer 32 and the gas-liquid mixing inlet 317 of the packed tower A31, enters the carbonization synthesis cavity 312 of the packed tower A31, fully contacts, and the following chemical reaction occurs: NH3·H2O+CO2→(NH4)2CO3; the ammonium carbonate solution generated by the reaction flows downward and finally collects in the bottom liquid cavity 311 of the packed tower A31. The water mist sprayed by the water spraying assembly can form a water seal between the carbonization synthesis cavity 312 and the tail gas cavity 313 of the packed tower A31, and is used for dissolving the volatilized ammonia gas, avoiding the ammonia gas entering the tail gas cavity 313 and being discharged through the tail gas cavity 313. The ammonium carbonate solution discharged from the bottom liquid outlet 316 of the packed tower A31 is sampled and the ammonium carbonate concentration is detected: 1. If the ammonium carbonate concentration is lower than 350 g / L, it is determined that the ammonium carbonate solution is unqualified, the tenth port 351 and the eleventh port 352 of the three-way valve D are connected, and the ammonium carbonate solution discharged from the bottom liquid outlet 316 of the packed tower A31 returns to the carbonization synthesis cavity 312 of the packed tower A31 through the three-way valve D, the Venturi mixer 32 and the gas-liquid mixing inlet 317 of the packed tower A31 in sequence, and is concentrated. 2. If the ammonium carbonate concentration reaches 350 g / L, it is determined that the ammonium carbonate solution is qualified, the tenth port 351 and the twelfth port 353 of the three-way valve D are connected, and the ammonium carbonate solution discharged from the bottom liquid outlet 316 of the packed tower A31 is input into the ammonium carbonate solution storage tank 44 through the three-way valve D, for storage.

[0041] The storage tank assembly includes a precipitated mother liquor storage tank 41, an alkali liquor storage tank 42, an ammonia water storage tank 43 and an ammonium carbonate solution storage tank 44. The precipitated mother liquor storage tank 41 is provided with a liquid inlet A and a liquid outlet A, the liquid inlet A of the precipitated mother liquor storage tank 41 is connected with the static pressure filter 13, and the liquid outlet A of the precipitated mother liquor storage tank 41 is connected with the sixth port of the three-way valve B. The alkali liquor storage tank 42 is connected with the fifth port of the three-way valve B. The ammonia water storage tank 43 is provided with a liquid inlet C and a liquid outlet C, the liquid inlet C of the ammonia water storage tank 43 is connected with the third port 243 of the three-way valve A, and the liquid outlet C of the ammonia water storage tank 43 is connected with the ammonia water inlet 318 of the packed tower A31. The ammonium carbonate solution storage tank 44 is connected with the twelfth port 353 of the three-way valve D.

[0042] The tail gas treatment assembly comprises a packed tower B51 and a dilute nitric acid storage tank 52. The packed tower B51 comprises, from bottom to top, a liquid phase cavity 511, a packed absorption cavity 512 and a gas phase cavity 513. The packed tower B51 is provided with a spraying component at the junction of the packed absorption cavity 512 and the gas phase cavity 513, which is used to spray misty dilute nitric acid into the packed absorption cavity 512. The packed tower B51 is provided with a non-condensable gas outlet 514 at the top, which is connected to the gas phase cavity 513. The packed tower B51 is provided with a dilute nitric acid inlet 515 on the side wall, which is connected to the spraying component. The packed tower B51 is provided with a non-condensable gas inlet 516 on the side wall, which is connected to the junction of the liquid phase cavity 511 and the packed absorption cavity 512. The packed tower B51 is provided with a tail gas inlet 517 on the side wall, which is connected to the junction of the liquid phase cavity 511 and the packed absorption cavity 512. The packed tower B51 is provided with an ammonium nitrate solution outlet 518 at the bottom, which is connected to the liquid phase cavity 511. The non-condensable gas inlet 516 of the packed tower B51 is connected to the non-condensable gas outlet 233 of the condenser 23, and the tail gas inlet 517 of the packed tower B51 is connected to the tail gas outlet 315 of the packed tower A31. The dilute nitric acid storage tank 5 is connected to the dilute nitric acid inlet 515 of the packed tower B51.

[0043] The tail gas treatment assembly is used to treat the non-condensable gas (mainly composed of ammonia) discharged from the stripping tower 21 and the upper end of the packed tower A31. The non-condensable gas discharged from the ammonia gas outlet 214 of the stripping tower 21 flows upward through the gas phase inlet 231 of the condenser 23, the non-condensable gas outlet 233 of the condenser 23 and the non-condensable gas inlet 516 of the packed tower B51, and enters the packed absorption cavity 512 of the packed tower B51. The tail gas discharged from the tail gas outlet 315 of the packed tower A31 enters the packed absorption cavity 512 of the packed tower B51 through the tail gas inlet 517 of the packed tower B51 and flows upward. The dilute nitric acid in the dilute nitric acid storage tank 52 enters the spraying component of the packed tower B51 through the dilute nitric acid inlet 515 of the packed tower B51 and sprays downward. The upward flowing ammonia gas and the downward spraying dilute nitric acid counter-currently contact each other, mass transfer occurs, and the following chemical reaction occurs: NH3+ HNO3→ NH4NO3. The ammonium nitrate solution generated by the reaction flows downward and collects in the liquid phase cavity 511. Subsequently, the ammonium nitrate solution can be sent back to the deamination assembly for recycling and treatment.

[0044] Preferably, the deamination assembly further comprises a tube-in-shell heat exchanger A27 arranged between the precipitated mother liquor storage tank 41 and the three-way valve C. The tube-in-shell heat exchanger A27 has a tube cavity and a shell cavity inside, and has a shell inlet, a shell outlet, a tube inlet and a tube outlet outside, the shell inlet and the shell outlet are both connected to the shell cavity, and the tube inlet and the tube outlet are both connected to the tube cavity. The shell inlet of the tube-in-shell heat exchanger A27 is communicated with the liquid outlet A of the precipitated mother liquor storage tank 41, the shell outlet of the tube-in-shell heat exchanger A27 is communicated with the sixth port 253 of the three-way valve B, the tube inlet of the tube-in-shell heat exchanger A27 is communicated with the ninth port 263 of the three-way valve C, and a pipeline for discharging column still liquid is connected to the tube outlet of the tube-in-shell heat exchanger A27. The tube-in-shell heat exchanger A27 is used to recover the residual heat of the column still liquid in the stripping tower 21, and preheat the precipitated mother liquor, thereby reducing the energy consumption of the stripping tower 21.

[0045] Preferably, the carbonization synthesis assembly further comprises a tube-in-shell heat exchanger B36 arranged between the bottom liquid outlet 316 of the packed tower A31 and the solution inlet 321 of the Venturi mixer 32. The tube-in-shell heat exchanger B36 is provided with a cooling water inlet, a cooling water outlet, an ammonium carbonate solution inlet and an ammonium carbonate solution outlet. The ammonium carbonate solution inlet of the tube-in-shell heat exchanger B36 is communicated with the bottom liquid outlet 316 of the packed tower A31, and the ammonium carbonate solution outlet of the tube-in-shell heat exchanger B36 is communicated with the solution inlet 321 of the Venturi mixer 32. The tube-in-shell heat exchanger B36 is used to continuously cool the ammonium carbonate solution, so that the inside of the packed tower A31 is kept at a suitable reaction temperature, and the exothermic reaction occurring inside the packed tower A31 can continue uninterrupted.

[0046] Preferably, a pump A is arranged on the pipeline between the thickener 11 and the plate-and-frame filter press 12, and a pump B is arranged on the pipeline between the plate-and-frame filter press 12 and the static pressure filter 13. A pump C is arranged on the pipeline between the second port 242 of the three-way valve A and the ammonia water backflow port 218 of the stripping tower 21, a pump D is arranged on the pipeline between the third port 243 of the three-way valve A and the ammonia water storage tank 33, and a pump E is arranged on the pipeline between the fourth port 251 of the three-way valve B and the mother liquor alkali liquid inlet 219 of the stripping tower 21. A pump F is arranged on the pipeline between the eighth port 262 of the three-way valve C and the column still liquid backflow port 217 of the stripping tower 21. A pump G is connected to the pipeline connected to the tube outlet of the tube-in-shell heat exchanger. A pump H is arranged on the pipeline between the liquid outlet E of the static pressure filter 13 and the liquid inlet A of the precipitated mother liquor storage tank 31, and a pump I is arranged on the pipeline between the dilute nitric acid storage tank 52 and the dilute nitric acid inlet 515 of the packed tower B51. The above-mentioned several pumps are arranged to provide power for the flow of liquid between the devices.

[0047] Preferably, a flow control valve A is arranged on the pipeline between the water vapor generating device 22 and the vapor inlet 216 of the stripping column 21, a flow control valve B is arranged on the pipeline between the lye storage tank 32 and the fifth port 252 of the three-way valve B, and a flow control valve C is arranged on the pipeline between the liquid outlet A of the precipitate mother liquor storage tank 31 and the shell inlet of the shell-and-tube heat exchanger 27. A flow control valve D is arranged on the pipeline between the liquid inlet of the carbon dioxide vaporizer 33 and the liquid carbon dioxide storage tank 34. The flow control valve A is used to control the amount of high-temperature water vapor (100℃) entering the stripping column 21, so as to control the temperature of the column liquid inside the stripping column 21, and when the column liquid temperature is controlled within an appropriate range (95-105℃), the decomposition reaction of ammonium hydroxide is facilitated. The flow control valve B is used to control the amount of sodium hydroxide solution entering the stripping column 21, so as to control the reaction efficiency inside the stripping column 21. The flow control valve C is used to control the amount of precipitate mother liquor entering the stripping column 21, so as to control the reaction efficiency inside the stripping column 21.

[0048] Briefly describe the working process of the application:

[0049] The preparation system of the crystallizing agent based on the ammonium diuranate precipitate mother liquor is used for recycling the ammonium diuranate precipitate mother liquor in a uranium purification process to prepare an ammonium carbonate solution, and the operation is as follows:

[0050] S01, remove the solid phase:

[0051] 1. The thickener 11 performs preliminary solid-liquid separation on the product after the reaction of uranyl nitrate and ammonium hydroxide, the solid phase ammonium diuranate is discharged and enters the subsequent process of uranium purification for preparing triuranium ammine carbonate, and the liquid phase precipitate mother liquor flows into the plate-and-frame filter press 12 through a pipeline for further solid-liquid separation;

[0052] 2. The plate-and-frame filter press 12 traps the fine crystals remaining in the precipitate mother liquor, and the liquid phase composition obtained after the trapping flows into the static pressure filter 13 for further solid-liquid separation;

[0053] 3. The static pressure filter 13 performs inspection filtration on the precipitate mother liquor, further filters the fine crystals remaining in the precipitate mother liquor, so that the uranium content in the precipitate mother liquor discharged from the static pressure filter 13 is <15 mg / L, and the suspended solids SS is <200 mg / L;

[0054] 4. The precipitate mother liquor discharged from the static pressure filter enters the precipitate mother liquor storage tank 31 and is stored for 3-5 months, so that the radioactivity intensity is reduced to the natural uranium level.

[0055] In the second and third sub-steps of this step, the composition of the fine crystals includes ammonium diuranate and uranium oxide impurities.

[0056] In the second and third sub-steps of this step, the filter residues filtered by the plate-and-frame filter 12 and the static pressure filter 13 are returned to the thickener 11 to avoid loss of uranium.

[0057] In the third sub-step of this step, if the precipitate mother liquor discharged from the static pressure filter 13 does not meet the requirements of uranium content < 15 mg / L and suspended solids SS < 200 mg / L, the filtering functions of the thickener 11, the plate-and-frame filter 12 and the static pressure filter 13 are checked to see if they are normal, and after the filtering functions of the thickener 11, the plate-and-frame filter 12 and the static pressure filter 13 are adjusted to be normal, the precipitate mother liquor is returned to the thickener 11 to remove the solid phase again.

[0058] S02, fixed ammonia is converted into free ammonium:

[0059] 1. The precipitate mother liquor after standing storage is input into the shell cavity of the tube-shell heat exchanger 27, the precipitate mother liquor in the shell cavity exchanges heat with the column still liquid in the tube cavity of the tube-shell heat exchanger, is warmed up, and then enters the gas-liquid mass transfer cavity 212 of the stripping column 21 through the sixth port 253 of the three-way valve B, the fourth port 251 of the three-way valve B and the mother liquor lye inlet 219 of the stripping column 21, and is sprayed downward;

[0060] 2. The sodium hydroxide solution stored in the lye storage tank 32 enters the gas-liquid mass transfer cavity 212 of the stripping column 21 through the fifth port 252 of the three-way valve B, the fourth port 251 of the three-way valve B and the mother liquor lye inlet 219 of the stripping column 21, and is sprayed downward;

[0061] 3. The high-temperature water vapor produced by the water vapor generating device 22 enters the gas-liquid mass transfer cavity 212 of the stripping column 21 through the steam inlet 216 of the stripping column 21, and flows upward;

[0062] 4. In the gas-liquid mass transfer cavity 212 of the stripping column 21, the upward flowing water vapor and the downward sprayed mixed liquid (the mixed liquid is obtained by mixing the sodium hydroxide solution and the precipitate mother liquor) counter-currently contact, gas-liquid mass transfer occurs, and the following chemical reactions occur: NH4NO3 + NaOH → NaNO3 + NH4OH; The sodium nitrate solution and the ammonium hydroxide solution produced by the reaction flow downward and collect in the column still liquid cavity 211 to form column still liquid; In the column still liquid cavity 211 of the stripping column 21, the ammonium hydroxide is decomposed by heat, and the following decomposition reaction occurs: NH4OH → NH3↑ + H2O; The water produced by the decomposition remains in the column still liquid cavity 211, and the ammonia gas produced by the decomposition flows upward and is discharged to the outside of the stripping column 21 through the gas-liquid mass transfer cavity 212, the ammonia gas cavity 213 and the ammonia gas outlet 214 in turn; Based on the above two reactions, the fixed ammonia in the precipitate mother liquor is converted into free ammonia.

[0063] The first, second and third sub-steps of this step are performed simultaneously.

[0064] In the second sub-step of the step, the mass fraction of the sodium hydroxide solution is 20-50%.

[0065] In the third sub-step of the step, the temperature of the high-temperature water vapor is between 95-100℃.

[0066] In the fourth sub-step of the step, the main component of the tower bottom liquid is sodium nitrate, and the secondary component is ammonium hydroxide which has not yet decomposed.

[0067] In the fourth sub-step of the step, the temperature of the ammonia cavity 213 of the stripping column 21 is controlled between 90-100℃ (the temperature control of the ammonia cavity 213 can be achieved by adjusting the amount of high-temperature water vapor entering the stripping column 21), the temperature of the tower bottom liquid in the tower bottom liquid cavity 211 of the stripping column 21 is controlled between 95-105℃ (the temperature control of the tower bottom liquid can be achieved by adjusting the amount of high-temperature water vapor entering the stripping column 21), and the pH of the tower bottom liquid in the tower bottom liquid cavity 211 of the stripping column 21 is controlled between 10-13 (the pH control of the tower bottom liquid can be achieved by adjusting the amount of sodium hydroxide solution entering).

[0068] S03, processing the tower bottom liquid:

[0069] The tower bottom liquid in the tower bottom liquid cavity 211 of the stripping column 21 is sampled to detect the ammonia nitrogen content;

[0070] If [NH4±N] < 15mg / L, the seventh port 261 of the three-way valve C is communicated with the ninth port 263, the tower bottom liquid in the tower bottom liquid cavity 211 of the stripping column 21 is discharged from the tower bottom liquid outlet 215 of the stripping column 21, and then enters the tube cavity of the shell-and-tube heat exchanger 27 through the three-way valve C. The tower bottom liquid in the tube cavity of the shell-and-tube heat exchanger 27 exchanges heat with the precipitate mother liquor in the shell cavity of the shell-and-tube heat exchanger 27, the precipitate mother liquor is preheated, and the tower bottom liquid after heat exchange is discharged from the tube cavity of the shell-and-tube heat exchanger 27, and is discharged as waste water or enters the waste water treatment process to recover nitrate.

[0071] If [NH4±N] ≥ 15mg / L, the seventh port 261 of the three-way valve C is communicated with the eighth port 262, the tower bottom liquid in the tower bottom liquid cavity 211 of the stripping column 21 is discharged from the tower bottom liquid outlet 215 of the stripping column 21, and then returns to the tower bottom liquid cavity 211 of the stripping column 21 through the three-way valve C and the tower bottom liquid reflux port 217 of the stripping column 21, and continues the decomposition reaction of ammonium hydroxide.

[0072] S04, collecting ammonia water:

[0073] 1. The gas in the ammonia chamber 213 of the stripping tower 21 is a mixture of ammonia, water vapor, and other non-condensable gases. After the mixed gas is discharged from the ammonia outlet 214 of the stripping tower 21, it enters the interior of the condenser 23 through the gas phase inlet 231 of the condenser 23 and condenses to form ammonia water. The reaction that occurs during the condensation process is as follows: NH3↑+H2O↑→NH3·H2O; the ammonia water is discharged through the liquid phase outlet 232 of the condenser 23, and the non-condensable gases are discharged from the non-condensable gas outlet 233 of the condenser 23. Then, it enters the waste gas treatment process to convert the free ammonium in it into fixed ammonia.

[0074] 2. Sample the ammonia water discharged from the liquid phase outlet 232 of condenser 23 and test the ammonia water concentration;

[0075] If the mass fraction of ammonia water is between 15-20%, then the first port 241 and the third port 243 of the three-way valve A are connected, and the ammonia water discharged from the liquid phase outlet 232 of the condenser 23 enters the ammonia water storage tank 33 through the three-way valve A for storage.

[0076] If the mass fraction of ammonia is less than 15%, the first port 241 of the three-way valve A is connected to the second port 242. The ammonia discharged from the liquid phase outlet 232 of the condenser 23 returns to the gas-liquid mass transfer chamber 212 of the stripping tower 21 through the three-way valve A and the ammonia return port 218 of the stripping tower 21, and undergoes the following decomposition reaction: NH3·H2O→NH3↑+H2O↑. At the same time, the supply of high-temperature water vapor to the interior of the stripping tower 21 is reduced, thereby achieving the purpose of increasing the ammonia concentration in the ammonia chamber 213 of the stripping tower 21.

[0077] If the mass fraction of ammonia water is higher than 15%, the first port 241 of the three-way valve A is connected to the second port 242. The ammonia water discharged from the liquid phase outlet 232 of the condenser 23 returns to the gas-liquid mass transfer chamber 212 of the stripping tower 21 through the three-way valve A and the ammonia water return port 218 of the stripping tower 21, and undergoes the following decomposition reaction: NH3·H2O→NH3↑+H2O↑. At the same time, the supply of high-temperature steam to the interior of the stripping tower 21 is increased, thereby reducing the ammonia concentration in the ammonia chamber 213 of the stripping tower 21.

[0078] S05, ammonia carbonization treatment:

[0079] 1. The ammonia water stored in the ammonia water storage tank 43 is discharged and enters the carbonization synthesis chamber 312 of the packed tower A31 through the ammonia water inlet 318;

[0080] 2. The liquid carbon dioxide stored in the liquid carbon dioxide storage tank 34 is vaporized by the carbon dioxide vaporizer 33 and then enters the carbonization synthesis chamber 312 of the packed tower A31 through the gas inlet 322 of the Venturi mixer 32, the gas-liquid mixing outlet 323 of the Venturi mixer 32 and the gas-liquid mixing inlet 317 of the packed tower A31 in sequence.

[0081] 3、The ammonia water and carbon dioxide are fully contacted in the carbonation synthesis cavity 312 of the packing tower A31, and the following chemical reaction occurs: NH3·H2O+CO2→(NH4)2CO3; The ammonium carbonate solution generated by the reaction flows downward and collects in the bottom liquid cavity 311 of the packing tower A31;

[0082] 4、The water spray assembly sprays water mist into the carbonation synthesis cavity 312, thereby forming a water seal between the carbonation synthesis cavity 312 and the tail gas cavity 313 of the packing tower A31, for dissolving the ammonia gas volatilized from the ammonia water, avoiding the ammonia gas entering the tail gas cavity 313 and being discharged through the tail gas cavity 313.

[0083] 5、The ammonium carbonate solution discharged from the bottom liquid outlet 316 of the packing tower A31 is sampled and detected for ammonium carbonate concentration, which is processed in the following two cases: a、If the ammonium carbonate concentration is lower than 350g / L, it is determined that the ammonium carbonate solution is unqualified, the tenth port 351 and the eleventh port 352 of the three-way valve D are connected, and the ammonium carbonate solution discharged from the bottom liquid outlet 316 of the packing tower A31 is returned to the carbonation synthesis cavity 312 of the packing tower A31 in sequence through the three-way valve D, the Venturi mixer 32 and the gas-liquid mixing inlet 317 of the packing tower A31, for concentration treatment; b、If the ammonium carbonate concentration reaches 350g / L, it is determined that the ammonium carbonate solution is qualified, the tenth port 351 and the twelfth port 353 of the three-way valve D are connected, and the ammonium carbonate solution discharged from the bottom liquid outlet 316 of the packing tower A31 is input into the ammonium carbonate solution storage tank 44 through the three-way valve D, for storage.

[0084] The first and second sub-steps of this step are performed simultaneously, and the third and fourth sub-steps of this step are performed simultaneously.

[0085] S06, tail gas treatment:

[0086] 1、The non-condensable gas discharged from the ammonia gas outlet 214 of the stripping tower 21 flows upward into the packing absorption cavity 512 of the packing tower B51 in sequence through the gas phase inlet 231 of the condenser 23, the non-condensable gas outlet 233 of the condenser 23 and the non-condensable gas inlet 516 of the packing tower B51;

[0087] 2、The tail gas discharged from the tail gas outlet 315 of the packing tower A31 flows upward into the packing absorption cavity 512 of the packing tower B51 through the tail gas inlet 517 of the packing tower B51;

[0088] 3、The dilute nitric acid in the dilute nitric acid storage tank 52 is sprayed downward into the spraying component of the packing tower B51 through the dilute nitric acid inlet 515 of the packing tower B51;

[0089] 4. The upward flowing ammonia gas is countercurrently contacted with the downward spraying dilute nitric acid to occur gas-liquid mass transfer, and the following chemical reaction occurs: NH3+ HNO3→ NH4NO3; the generated ammonium nitrate solution flows downward and is collected in the liquid phase cavity 511.

[0090] The first, second and third sub-steps in this step are performed simultaneously.

[0091] After this step is completed, the ammonium nitrate solution is sent back to the deamination assembly for recycling.

Claims

1. A system for preparing a crystallizing agent based on the ammonium diuranate precipitate mother liquor, characterized by the fact that it comprises: Includes solid-liquid separation components, ammonia removal components, carbonization synthesis components, and storage tank components; The solid-liquid separation assembly includes a thickener, a plate and frame filter press, and a static pressure filter. The filtrate overflowing from the thickener is connected to the plate and frame filter press, and the filtrate discharged from the plate and frame filter press is connected to the static pressure filter. The ammonia removal assembly includes a stripping tower, a steam generator, a condenser, three-way valves A, B, and C. The stripping tower, from bottom to top, has a bottom liquid chamber, a gas-liquid mass transfer chamber, and an ammonia chamber. The top of the stripping tower has an ammonia outlet connected to the ammonia chamber, and the bottom of the stripping tower has a bottom liquid outlet connected to the bottom liquid chamber. The side wall of the stripping tower has a steam inlet connecting to the interface between the bottom liquid chamber and the gas-liquid mass transfer chamber, a bottom liquid reflux port connecting to the interface between the bottom liquid chamber and the gas-liquid mass transfer chamber, an ammonia water reflux port connecting to the junction of the gas-liquid mass transfer chamber and the ammonia chamber, and a mother liquor alkali inlet connecting to the gas-liquid mass transfer chamber. The steam generator is connected to the steam inlet of the stripping tower. The condenser has a gas phase inlet, a liquid phase outlet, and a non-condensable gas outlet. The condenser's gas phase inlet is connected to the ammonia outlet of the stripping tower; three-way valve A has a first port, a second port, and a third port. The first port of three-way valve A is connected to the liquid phase outlet of the condenser, the second port of three-way valve A is connected to the ammonia water reflux port of the stripping tower, and the third port of three-way valve A is used to output ammonia water; three-way valve B has a fourth port, a fifth port, and a sixth port. The fourth port of three-way valve B is connected to the mother liquor alkali inlet of the stripping tower, the fifth port of three-way valve B is used to receive alkali, and the sixth port of three-way valve B is used to receive mother liquor; three-way valve C has a seventh port, an eighth port, and a ninth port. The seventh port of three-way valve C is connected to the bottom liquid outlet of the stripping tower, the eighth port of three-way valve C is connected to the bottom liquid reflux port of the stripping tower, and the ninth port of three-way valve C is used to discharge the bottom liquid; The carbonization synthesis assembly includes a packed tower A, a Venturi mixer, a carbon dioxide vaporizer, a liquid carbon dioxide storage tank, and a three-way valve D. The packed tower A has, from bottom to top, a bottom liquid chamber, a carbonization synthesis chamber, and a tail gas chamber. A water spray component is located at the interface between the carbonization synthesis chamber and the tail gas chamber inside the packed tower A, used to spray water mist into the carbonization synthesis chamber. A deionized water inlet is located on the side wall of the packed tower A, connecting to the water spray component. A tail gas outlet is located at the top of the packed tower A, connecting to the tail gas chamber. A bottom liquid outlet is located at the bottom of the packed tower A, connecting to the bottom liquid chamber. A gas-liquid mixing inlet is located on the side wall of the packed tower A, connecting to the interface between the bottom liquid chamber and the carbonization synthesis chamber. The packed tower A has an ammonia water inlet on its side wall, which connects to the carbonization synthesis chamber. The venturi mixer has a solution inlet and a gas inlet at its upper end, and a gas-liquid mixing outlet at its lower end, which connects to the gas-liquid mixing inlet of the packed tower A. The carbon dioxide vaporizer has a liquid inlet and a gas outlet at both ends, with the liquid inlet connected to a liquid carbon dioxide storage tank and the gas outlet connected to the gas inlet of the venturi mixer. The three-way valve D has a tenth port, an eleventh port, and a twelfth port. The tenth port of the three-way valve D connects to the bottom liquid outlet of the packed tower A, and the eleventh port of the three-way valve D connects to the solution inlet of the venturi mixer. The storage tank assembly includes a mother liquor storage tank, an alkali storage tank, an ammonia storage tank, and an ammonium carbonate solution storage tank. The mother liquor storage tank is equipped with an inlet A and an outlet A. The inlet A of the mother liquor storage tank is connected to a static pressure filter, and the outlet A of the mother liquor storage tank is connected to the sixth port of a three-way valve B. The alkali storage tank is connected to the fifth port of the three-way valve B. The ammonia storage tank is equipped with an inlet C and an outlet C. The inlet C of the ammonia storage tank is connected to the third port of the three-way valve A, and the outlet C of the ammonia storage tank is connected to the ammonia inlet of the packed tower A. The ammonium carbonate solution storage tank is connected to the twelfth port of a three-way valve D.

2. The system for preparing a crystallizing agent based on the ammonium diuranate precipitation mother liquor according to claim 1, characterized in that: The thickener has a separation chamber inside, and an overflow port on the upper side wall of the thickener for discharging the clarified liquid from the upper part of the separation chamber; the plate and frame filter press has an inlet D and an outlet D, and the inlet D of the plate and frame filter press is connected to the overflow port of the thickener to receive the clarified liquid discharged from the thickener; the static pressure filter has an inlet E and an outlet E, and the inlet E of the static pressure filter is connected to the outlet E of the plate and frame filter press to receive the filtrate discharged from the plate and frame filter press, and the outlet E of the static pressure filter is connected to the inlet A of the sedimentation mother liquor storage tank to discharge the filtrate filtered by the static pressure filter.

3. The system for preparing a crystallizing agent based on an ammonium diuranate precipitation mother liquor according to claim 2, characterized in that: The ammonia removal assembly also includes a shell-and-tube heat exchanger A located between the mother liquor storage tank and the three-way valve C. The shell-and-tube heat exchanger A has a shell-side inlet, a shell-side outlet, a tube-side inlet, and a tube-side outlet. The shell-side inlet of the shell-and-tube heat exchanger A is connected to the outlet A of the mother liquor storage tank, the shell-side outlet of the shell-and-tube heat exchanger A is connected to the sixth port of the three-way valve B, the tube-side inlet of the shell-and-tube heat exchanger A is connected to the ninth port of the three-way valve C, and a pipe for discharging the bottom liquid is connected to the tube-side outlet of the shell-and-tube heat exchanger A.

4. The system for preparing a crystallizing agent based on an ammonium diuranate precipitation mother liquor according to claim 3, characterized in that: The carbonation synthesis assembly also includes a shell-and-tube heat exchanger B located between the bottom liquid outlet of the packed tower A and the solution inlet of the Venturi mixer; the shell-and-tube heat exchanger B is provided with a cooling water inlet, a cooling water outlet, an ammonium carbonate solution inlet, and an ammonium carbonate solution outlet; the ammonium carbonate solution inlet of the shell-and-tube heat exchanger B is connected to the bottom liquid outlet of the packed tower A, and the ammonium carbonate solution outlet of the shell-and-tube heat exchanger B is connected to the solution inlet of the Venturi mixer.

5. The crystallizer preparation system based on ammonium diuranate precipitate mother liquor as described in claim 4, characterized in that: It also includes a tail gas treatment component; the tail gas treatment component includes a packed tower B and a dilute nitric acid storage tank; the packed tower B has a liquid phase chamber, a packed absorption chamber and a gas phase chamber arranged sequentially from bottom to top inside the packed tower B; a spray component is provided at the junction of the packed absorption chamber and the gas phase chamber inside the packed tower B, the spray component is used to spray mist-like dilute nitric acid into the packed absorption chamber; the top of the packed tower B has a non-condensable gas outlet connected to the gas phase chamber; the side wall of the packed tower B has a dilute nitric acid inlet connected to the spray component; the side wall of the packed tower B has a non-condensable gas inlet connected to the junction of the liquid phase chamber and the packed absorption chamber; the side wall of the packed tower B has a tail gas inlet connected to the junction of the liquid phase chamber and the packed absorption chamber; the bottom of the packed tower B has an ammonium nitrate solution outlet connected to the liquid phase chamber; the non-condensable gas inlet of the packed tower B is connected to the non-condensable gas outlet of the condenser; the tail gas inlet of the packed tower B is connected to the tail gas outlet of the packed tower A; the dilute nitric acid storage tank is connected to the dilute nitric acid inlet of the packed tower B.

6. The crystallizer preparation system based on ammonium diuranate precipitate mother liquor as described in claim 5, characterized in that: Pump A is installed on the pipeline between the thickener and the plate and frame filter press; pump B is installed on the pipeline between the plate and frame filter press and the static pressure filter; pump C is installed on the pipeline between the second port of three-way valve A and the ammonia reflux port of the stripping tower; pump D is installed on the pipeline between the third port of three-way valve A and the ammonia storage tank; pump E is installed on the pipeline between the fourth port of three-way valve B and the mother liquor alkali inlet of the stripping tower; pump F is installed on the pipeline between the eighth port of three-way valve C and the bottom liquid reflux port of the stripping tower; pump G is connected to the pipeline connected to the tube side outlet of shell and tube heat exchanger A; pump H is installed on the pipeline between the ammonium carbonate solution inlet of shell and tube heat exchanger B and the bottom liquid outlet of packed tower A; pump I is installed on the pipeline between the dilute nitric acid storage tank and the dilute nitric acid inlet of packed tower B.

7. The crystallizer preparation system based on ammonium diuranate precipitate mother liquor as described in claim 6, characterized in that: A flow control valve A is installed on the pipeline between the steam generator and the steam inlet of the stripping tower; a flow control valve B is installed on the pipeline between the alkali storage tank and the fifth port of the three-way valve B; a flow control valve C is installed on the pipeline between the outlet A of the precipitated mother liquor storage tank and the shell-side inlet of the shell-and-tube heat exchanger; and a flow control valve D is installed on the pipeline between the inlet of the carbon dioxide vaporizer and the liquid carbon dioxide storage tank.

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