JP3225985B2 - Uranyl nitrate denitration apparatus and denitration method using this apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to uranium trioxide (UO ₂ ) by thermal decomposition of solid uranyl nitrate hydrate (UO ₂ (NO ₃ ) ₂ .xH ₂ O, 3 ≦ x ≦ 6) and denitration. _The present invention relates to a denitration device for uranyl nitrate obtained in ₃ ) and a denitration method using this device . More particularly, the present invention relates to an apparatus for converting uranyl nitrate hydrate obtained by a crystallization method to dehydrated uranyl nitrate, and then thermally decomposing the uranyl nitrate for denitration, and a method using the apparatus. .

[0002]

2. Description of the Related Art The present applicant has proposed a method for obtaining a solid uranyl nitrate hydrate by a crystallization method (for example,
JP-A-3-78698). As a method of obtaining UO ₃ via this solid uranyl nitrate hydrate, for example, the following 2
There are two ways. In the first method, a uranyl nitrate solution is formed into a slurry containing uranyl nitrate hydrate by a crystallization method, and ammonia is reacted with the slurry to produce ammonium diuranate (ADU) in a slurry state. This is a method in which UO ₃ is obtained by denitration by roasting (pyrolysis) after drying. The second method is a method in which uranyl nitrate crystals are formed by a crystallization method, the uranyl nitrate crystals are directly converted into a solution by heating, and the resulting solution is introduced into a reaction fluidized bed and denitrated to obtain UO ₃ . But,
The first method requires waste liquid treatment by addition of ammonia, and requires many steps such as solid-liquid separation of slurry ADU, drying and roasting, and the second method requires uranyl nitrate crystals. It requires an apparatus for heating and melting and ancillary equipment for forming a reaction fluidized bed, and the apparatus becomes large.

On the other hand, solid uranyl nitrate hydrate is melted, this solution is dispersed to form spherical droplets having a diameter of 10 to 500 μm, and the droplets are cooled to form spherical solid particles. Is heated at a temperature equal to or lower than the melting point to remove hydrates to obtain UO ₃ , US Pat. No. 3,355,355.
No. 393. In this method, in the step of removing hydrates, first, three hours of water of hydration are removed from uranyl nitrate hexahydrate at a temperature of 40 ° C. for a sufficient time, and then one molecule of water is removed at a temperature of 80 ° C. Hydrated water at 140 ° C
One more molecule of water of hydration is removed at a temperature of and then the last water of hydration is removed at a temperature of 180 ° C., and after all the water of hydration is completely removed, the temperature is raised to a final 300 ° C. Denitration is being performed. However, UO ₃ obtained by this method had a disadvantage that the specific surface area was relatively small and the activity was poor.

[0004] As a method for improving this point, a solid uranyl nitrate hydrate is heated from an initial temperature always lower than the melting temperature to 3%.
A method of obtaining UO ₃ by heating the product temperature at each moment to a final temperature of 30 ° C. to 500 ° C. while always keeping the temperature of the product at a value lower than the melting temperature corresponding to the composition of the product at that moment is disclosed in Japanese Patent Publication No. No. 9735. in this way,
Maintaining the partial pressure of water vapor in the processing vessel at 65 mmHg or less,
The rate of temperature rise from the initial temperature to the final temperature is at least 2 ° C / min, the heat treatment time is 195 minutes or less, and the temperature is dehydrated without maintaining the temperature at the constant temperature for a certain period of time from the initial temperature to the final temperature. And denitration are continuously raised without distinction.

[0005]

However, the methods described in U.S. Pat. No. 3,355,393 and Japanese Patent Publication No. 4-9735 both involve a fine temperature setting or raising in a series of steps. It is necessary to heat the product while maintaining a temperature that is always lower than the melting temperature corresponding to the composition of the product under the heating rate, so that the dehydration and denitration conditions are complicated, and the temperature control and handling are complicated. was there. In particular, the methods described in the above two publications do not perform denitration while monitoring the decrease in the hydrate of uranyl nitrate hydrate, so that when the type of starting material changes or the amount of denitration changes, denitration cannot be performed accurately. There was a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for converting a solid uranyl nitrate hydrate into an active UO with relatively simple control using a small facility.
Uranyl nitrate denitration apparatus which can be directly converted to ₃ , and its equipment
An object of the present invention is to provide a denitration method using an apparatus .

[0007]

Means for Solving the Problems The present inventors dehydrated unstable uranyl nitrate hexahydrate, which can be melted at 60 ° C., into a uranyl nitrate dihydrate dehydrated uranyl nitrate. Have reached the present invention based on the finding that a stable compound which does not melt even at a temperature of about 150 ° C. is obtained.

[0008]

That is, as shown in FIG. 2, the uranyl nitrate denitration apparatus of the present invention converts a solid uranyl nitrate hydrate 1 containing trihydrate to hexahydrate to a hydrate of not more than 2 hydrates. Rotary kiln 20 for dehydrating uranyl nitrate 6 containing waste
And a conversion device 50 for converting the dehydrated uranyl nitrate 6 into UO ₃ by heating it in an atmosphere having a continuous temperature distribution in the range of 150 to 350 ° C. to convert it into UO ₃ and at the same time obtain NOx with a low moisture content. Is provided. The characteristic configuration of the first rotary kiln 20 is that the first rotary kiln 20 has a guide blade 21a fixed to the inner surface of the pipe and the first rotatable core tube 21 is horizontally disposed, and the first rotatable core tube 21 rotates the first core tube 21.
A driving device 22 and a first feeder 2 provided at one end of the furnace tube 21 for supplying uranyl nitrate hydrate 1 into the furnace tube
3, a first discharge portion 24 provided at the other end of the furnace tube 21 for discharging the dehydrated uranyl nitrate 6, and a vacuum pump 25 for adjusting the pressure in the furnace tube 21 to a pressure of 0.01 to 10 mmHg.
And the inside of the furnace tube provided around the furnace tube 21
A first heater 26 for providing an atmosphere having a continuous temperature distribution within a range of 150 ° C., a measuring device 27 for measuring the weight of the furnace tube 21 and uranyl nitrate hydrate, and a measuring device 2
7 from the weight change rate of the uranyl nitrate hydrate salt
6 and a waste gas discharge unit 29 for discharging the waste gas in the furnace tube 21. As shown in FIG. 1, the uranyl nitrate of the present invention
The denitration method uses the above-mentioned denitration apparatus and does not contain trihydrate.
Uranyl nitrate hydrous salt containing sodium hexahydrate (UN
H) 1 to 30 to 15 under a pressure of 0.01 to 10 mmHg.
Put in an atmosphere with a continuous temperature distribution in the range of 0 ° C
Hydration of dihydrate or less by heating in a lever atmosphere
Vacuum dehydration step 2 for obtaining dehydrated uranyl nitrate 6 containing a substance,
The dehydrated uranyl nitrate 6 is heated at a temperature in the range of 150 to 350 ° C.
In an atmosphere with a continuous temperature distribution,
Low moisture content at the same time converted to UO ₃ 4 by heating
And a conversion step 3 for obtaining NOx5. Its features
The characteristic configuration is the vacuum dehydration step 2, in which heated urani nitrate is heated.
The hydrated salt and heat it according to its weight change rate.
To control the conditions.

[0010]

The furnace tube 21 is rotated by the driving device 22, and the pressure inside the furnace tube 21 is increased by 0.01 to 10 by the vacuum pump 25.
mmHg, and the temperature in the furnace tube 21 is increased from the feeder 23 to the discharge portion 24 by the heater 26 to 30 ° C. to 15 ° C.
The temperature is set so as to have a continuous temperature distribution within the range of 0 ° C. In this state, uranyl nitrate hydrate 1
Is supplied into the core tube 21. The uranyl nitrate hydrate 1 is vacuum-dehydrated in the furnace tube 21 as shown in the following equation (1).
The dehydrated uranyl nitrate 6 is discharged from the discharge unit 24. On the other hand, waste gas is discharged from the waste gas discharge unit 29. Here, the controller 28 calculates the weight change rate of the uranyl nitrate hydrate from the output of the measuring device 27, and adjusts the heating temperature of the uranyl nitrate hydrate so that the dehydrated uranyl nitrate 6 becomes dihydrate or less. Control. UO ₂ (NO ₃ ) ₂ .xH ₂ O → UO ₂ (NO ₃ ) ₂ .yH ₂ O + zH ₂ O (1) (However, 3 ≦ x ≦ 6, 0 <y ≦ 2, z = xy) The obtained dehydrated uranyl nitrate 6 was converted to 150-
It is introduced into an atmosphere having a continuous temperature distribution in the range of 350 ° C., and is heated in this atmosphere to be converted into UO ₃ as shown in the following formula (2), and at the same time NOx (NO, NO, NO ₂ ) is obtained. UO ₂ (NO ₃ ) ₂ .yH ₂ O → UO ₃ + NO + NO ₂ + O ₂ + yH ₂ O (2) The obtained UO ₃ powder becomes an active powder having a specific surface area of about 5 to 10 m ² / g.

[0011]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 2 and 3, a hopper 10 containing uranyl nitrate hydrate 1 is connected to a first rotary kiln 20 via a supply pipe 11 and a flexible pipe 12. An electromagnetic valve 13 is provided in the supply pipe 11.
The rotary kiln 20 includes a first core tube 21 and a first driving device 2.
2, the first feeder 23, the first discharge unit 24, and the vacuum pump 2
5, a first heater 26, a meter 27, a controller 28, and a waste gas discharge unit 29.

The core tube 21 is disposed horizontally, and spiral guide blades 21a are fixed to the inner surface of the core tube from one end to the other end. The core tube 21 has a driving device 22 near both ends thereof.
Is rotated by As shown in FIG. 3, the drive device 22 includes a pair of drive rollers 22a and 22b on which the furnace tube 21 is placed and in which the outer periphery of the furnace tube 21 contacts, and the rotating shaft 22c is driven by a motor (not shown). First feeder 23
Has one end connected to the lower end of the flexible tube 12 and the other end inserted into one end of the furnace tube 21. The first discharge unit 24 is provided at the other end of the furnace tube 21 so as to discharge the dehydrated uranyl nitrate 6, and the lower end thereof is connected to the flexible tube 31.
And a transport pipe 32 connected to an intermediate tank 33 for temporarily storing dehydrated uranyl nitrate. An electromagnetic valve 34 is provided in the middle of the transport pipe 32. This tank 33 has a pipe 3
The vacuum pump 25 is connected via 6. An electromagnetic valve 38 is provided in the middle of the pipe 36. The vacuum pump 25 makes the inside of the furnace tube 21 have a pressure of 0.01 to 10 mmHg.

The first heater 26 is provided around the furnace tube 21 and without contact with the furnace tube 21, for example, heaters 26a to 26d.
Are divided into four parts. These heaters 26a-2
6d heats the inside of the furnace tube 21 so as to have a temperature distribution of 30 ° C to 110 ° C. As shown in FIG. 3, the weighing device 27 is provided on the lower surface of the plate 22e for fixing the bearing 22d of the rotating shaft 22c, and weighs the core tube 21 and the uranyl nitrate hydrate inside the tube. The controller 28 includes the measuring device 2
7 is connected, the controller 28 calculates the rate of change in weight of uranyl nitrate hydrate per hour, and controls the first heater 26 based on the calculation result. The control output of the controller 28 is the aforementioned vacuum pump 25, the solenoid valves 13, 34.
And 38. The waste gas discharge part 29 is provided in the furnace tube 21.
At one end of the furnace to discharge waste gas in the furnace tube. The upper end of the waste gas discharge part 29 is a flexible pipe 39 and a discharge pipe 4.
1 is connected, and a valve 42 is provided in the middle of the discharge pipe 41.

An intermediate hopper 45 is connected to the intermediate tank 33 via a pipe 44, and an electromagnetic valve 46 is provided in the pipe 44. The intermediate hopper 45 is connected to the second rotary kiln 50 via the supply pipe 47. An electromagnetic valve 48 is provided in the supply pipe 47. The rotary kiln 50 includes a second furnace tube 51 having guide blades 51a, a second driving device 52, a second feeder 53, a second discharge unit 54, a second heater 56, and a first NOx discharge unit 57. These are the second heater 5
Except for the 6 and the first NOx discharge section 57, the configuration is the same as each section of the first rotary kiln 20. Second heater 56
Are, for example, the heaters 56a to 56
6d. These heaters 56a-
Reference numeral 56d heats the inside of the furnace tube 51 from the second feeder 53 to the second discharge portion 54 so as to have a temperature distribution of 150 ° C to 350 ° C. The first NOx discharge unit 57 is connected to the second discharge unit 5
The discharge portion 57 is connected to a discharge pipe 58. A valve 59 is provided in the middle of the discharge pipe 58. A storage tank 62 for UO ₃ is provided below the second discharge part 54 via a discharge pipe 61. A valve 63 is provided in the middle of the discharge pipe 61.

A method for denitrifying uranyl nitrate hydrate to UO ₃ using the apparatus having such a configuration will be described. <Vacuum dehydration step> First, the furnace tube 21 is rotated at a speed of about 1 to 5 rpm by the driving device 22, the electromagnetic valve 46 is closed, the electromagnetic valves 38 and 34 are opened, and the pressure inside the furnace tube 21 is To 0.01 to 10 mmHg. At the same time, the temperature in the furnace tube 21 is increased from the feeder 23 to the discharge unit 24 by the heaters 26a to 26d to reach 30 ° C to 110 ° C.
Set so that the temperature distribution becomes That is, the heater 26a is heated to a temperature of 30 ° C., the heater 26d is heated to a temperature of 110 ° C., and the heaters 26b and 26c are heated to an intermediate temperature between them. In this state, the solenoid valve 13 was opened for a predetermined time, and a predetermined amount of uranyl nitrate hydrate 1 having an average particle diameter of 200 to 300 μm obtained by crystallization was supplied from the hopper 10 to the feeder 23. In this example, the uranyl nitrate hydrate was hexahydrate.

In the furnace tube 21, uranyl nitrate hydrate was dehydrated in vacuum as it traveled toward the discharge portion 24 by the guide blades 21a, and became dehydrated uranyl nitrate of dihydrate or less at the discharge portion 24. The waste gas generated in the furnace tube 21 is discharged to a waste gas discharge unit 29.
Was discharged from. Here, the controller 28 calculates the weight change rate of the uranyl nitrate hydrate from the output of the measuring device 27 together with the opening / closing control of the solenoid valve, and adjusts the heating temperature of the uranyl nitrate hydrate to constantly maintain the dehydrated uranyl nitrate 6 in dihydrate. The heater 26 was controlled so as to be less than the object. Rotary kiln 2
0 is free from other fixed tubes in the flexible tubes 12, 31 and 39, and since the core tube 21 is not in contact with the heater 26, the measuring device 27 is
The rate of change in weight of the uranyl nitrate hydrate salt therein can be measured. The dehydrated uranyl nitrate 6 is temporarily stored in the intermediate tank 33 through the discharge part 24, the flexible pipe 31, and the transport pipe 32. The controller 28 closes the solenoid valve 38 and sets the solenoid valve 1
3 is opened and the next uranyl nitrate hydrate 1 is supplied to the rotary kiln 20. Next, the controller 28 controls the solenoid valve 34.
Is closed, the electromagnetic valve 46 is opened, and the dehydrated uranyl nitrate 6 is stored in the intermediate hopper 45 via the pipe 44.

<Conversion Step> Further, the furnace tube 51 is rotated by the driving device 52 at a speed of about 1 to 5 rpm, and the heater 56 a
The temperature in the furnace tube 51 is set so as to have a temperature distribution of 150 to 350 ° C. from the feeder 53 to the discharge unit 54 by the steps 56 to 56d. That is, the temperature of the heater 5 is set to 150 ° C. by the heater 56a, and to 350 ° C. by the heater 56d.
Heat is applied by 6b and 56c to an intermediate temperature between them. In this state, the solenoid valve 48 is opened and the hopper 45
The average particle size obtained from the first rotary kiln 20 from
0 to 300 μm of dehydrated uranyl nitrate 6 was supplied to the feeder 53. In the furnace tube 51, the dehydrated uranyl nitrate was denitrated as it traveled toward the discharge portion 54 by the guide blades 51a, and was completely converted into UO ₃ powder at the discharge portion 54. The UO ₃ powder in the discharge section 54 was stored in the storage tank 63. The resulting powder has a specific gravity of 2.0 g / cm ³ or less and a specific surface area of 5 g / cm ^3.
The powder was highly active at m ² / g. NOx emission unit 5
From No. 7, NOx containing almost no water was obtained through the discharge pipe 61.

FIGS. 4 and 5 show another conversion device according to the present invention. This conversion apparatus is a flat plate multi-chamber fluidized reaction bed 70 having a flat plate main body 71, a lower partition plate 72, and a supply port 73.
, An outlet 74, an upper partition plate 76, a third heater 77, a gas inlet 78, and a second NOx outlet 79. In this example, three lower partitioning plates 72 are erected on a dispersion plate 81 provided on the entire lower part of the layer main body 71. Above the dispersion plate 81, a fluidized bed for converting dehydrated uranyl nitrate into UO ₃ powder is formed. In this example, the dispersion plate 81 is formed in a porous mesh so that a flowing gas to be described later is permeable, but dehydrated uranyl nitrate and UO ₃ powder do not fall off. A wind box 82 is formed below the dispersion plate 81. The supply port 73 is provided at one end of the layer main body 71, and the intermediate hopper 45 is connected to the supply port 73 via a supply pipe 73 a and a valve 48. The discharge port 74 is provided at the other end of the layer main body 71, from which UO ₃ is taken out. Outlet 7
4 is connected to the storage tank 62 via a discharge pipe 74a and a valve 63.
Is connected. The upper partition plate 76 is provided on the top of the layer main body 71, and partitions the inside of the layer main body into five reaction chambers 71a, 71b, 71c, 71d, and 71e together with the lower partition plate 72.

As shown in FIG. 5, the heater 77 is connected to the layer body 7.
The five reaction chambers 71a to 71e provided on the peripheral wall of the first one are set to have an atmosphere having a continuous temperature distribution in the range of 150 to 350 ° C. from the supply port 73 to the discharge port 74. The gas introduction section 78 is provided at one end of the layer main body 71,
8 communicates with the wind box 82. The NOx discharge part 79 is piped through the top of each of the five reaction chambers 71a to 71e.

In the conversion apparatus constructed as described above, after the five reaction chambers 71a to 71e are brought into an atmosphere having a predetermined temperature distribution by the heater 77, the valve 48 is opened and dehydrated uranyl nitrate is supplied from the supply port 73 to the reaction chamber. 71a. At the same time, air as a flowing gas is introduced into each of the five reaction chambers 71a to 71e from the gas introduction unit 78 via the wind box 82 and the dispersion plate 81, and the supplied dehydrated uranyl nitrate is stirred and fluidized. As shown by the arrow in the figure, short path in the layer main body of the dehydrated uranyl nitrate is prevented by the upper partition plate 72, and the reaction chamber 71
b, 71c, 71d and 71e to be denitrated.
The UO ₃ powder was stored in the storage tank 63 in the reaction chamber 71e. The obtained powder showed the same physical property values as those of the above example. NOx containing almost no water is NO
It was discharged from the x discharge section 79.

[0021]

As described above, according to the present invention, there is no need to add an additive to a solid purified or recovered uranyl nitrate hydrate or to melt a solid uranyl nitrate hydrate without melting. It can be converted to active UO ₃ with small equipment. In addition, since denitration is performed while monitoring the state of reduction of hydrates of hydrated salts, even when the type of starting material changes or the amount of denitration changes, direct denitration can be performed with relatively simple control. In particular, NOx with a low moisture content is obtained as a by-product from the converter of the present invention. This NO
x has an advantage that it can be used for purging iodine from uranium or plutonium in nuclear fuel reprocessing, adjusting the valence of plutonium, and the like.

[Brief description of the drawings]

FIG. 1 is a denitration process diagram of uranyl nitrate of the present invention.

FIG. 2 is a configuration diagram of a uranyl nitrate denitration apparatus according to an embodiment of the present invention.

FIG. 3 is a sectional view taken along the line AA.

FIG. 4 is a configuration diagram of a denitration apparatus according to another embodiment of the present invention.

FIG. 5 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydrate uranyl nitrate 2 Vacuum dehydration process 3 Conversion process 6 Dehydrated uranyl nitrate 20 1st rotary kiln 21 1st core tube 21a Guide blade 22 1st drive device 23 1st feeder 24 1st discharge part 25 Vacuum pump 26 1st heater 27 Measuring instrument 28 Controller 29 Waste gas discharge unit 50 Second rotary kiln (conversion device) 51 Second furnace tube 51a Guide blade 52 Second drive unit 53 Second feed 54 Second discharge unit 56 Second heater 57 First NOx discharge unit Reference Signs List 70 Flat multi-chamber fluidized reaction bed (conversion device) 71 Layer main body 71a to 71e Reaction chamber 72 Lower partition plate 73 Supply port 74 Drain port 76 Upper partition plate 77 Third heater 78 Gas introduction unit 79 Second NOx discharge unit

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kenji Nishimura, Nakamachi, Naka-gun, Ibaraki Pref. 200830 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C01G 43/01

Claims (4)

(57) [Claims] 1. A first rotary kiln that converts a solid uranyl nitrate hydrate containing trihydrate to hexahydrate into dehydrated uranyl nitrate containing hydrates equal to or less than dihydrate (6). (20)
And a conversion device for converting the dehydrated uranyl nitrate (6) into UO ₃ by heating it in an atmosphere having a continuous temperature distribution in the range of 150 to 350 ° C. and simultaneously obtaining NOx with a low moisture content. (50, 70), wherein the first rotary kiln (20) has guide vanes (21a) fixed to the inner surface of the pipe and is horizontally disposed and rotatable. A first driving device (22) for rotating the furnace tube (21); and a urethane nitrate hydrate salt (1) provided in one end of the furnace tube (21). And a dehydrating uranyl nitrate (6) provided at the other end of the furnace tube (21).
A first discharge part (24) for discharging the furnace core, a vacuum pump (25) for adjusting the pressure in the furnace tube (21) to 0.01 to 10 mmHg, and a furnace pump provided around the furnace tube (21). 30-15
A first heater (26) for providing an atmosphere having a continuous temperature distribution within a range of 0 ° C .; a measuring device (27) for weighing the furnace tube (21) and uranyl nitrate hydrate salt (1); A controller (28) for controlling the first heater (26) based on a weight change rate of the uranyl nitrate hydrate salt of the measuring instrument (27); and a waste gas discharge section (29) for discharging waste gas in the furnace tube (21). )
A denitration device for uranyl nitrate, comprising: 2. A conversion device comprising: a rotatable second core tube (51) having guide vanes (51a) fixed to the inner surface of the tube and disposed horizontally, and rotating the core tube (51). A second driving device (52); dehydrated uranyl nitrate provided at one end of the furnace tube (51) and sent from a first discharge portion (24) of the first rotary kiln (20).
And supplying (6) the second feeder (53), a second discharging the UO ₃ provided at the other end of the core tube (51)
A discharge portion (54), provided in the periphery of the furnace tube (51), and moving through the inside of the furnace tube from the second feeder (53) to the second discharge portion (54) in the range of 150 to 3;
A second heater (56) for providing an atmosphere having a continuous temperature distribution within a range of 50 ° C., and a first NO for discharging NOx generated in the core tube (51).
x discharge unit (57) and a second rotary kiln (50) in which claim 1 denitrator uranyl nitrate according equipped with. 3. A conversion device comprising: a plate-shaped layer main body (71); a lower partition plate (72) for partitioning a lower portion in the layer main body (71); Dehydrated uranyl nitrate sent from the first discharge part (24) of the first rotary kiln (20)
A supply port (73) for supplying (6), and a discharge port provided at the other end of the layer body (71) for taking out UO ₃
(74), and the lower partition plate (7) provided on the top (75) of the layer body (71).
2) together with an upper partition plate (76) that partitions the inside of the layer body into a plurality of reaction chambers (71a to 71e) to prevent a short path of the dehydrated uranyl nitrate, and the plurality of the plurality of reaction chambers provided around the layer body (71). Reaction chamber (71a
To 71e) from the supply port (73) to the discharge port (74).
A third heater (77) for providing an atmosphere having a continuous temperature distribution within a range of 50 to 350 ° C., and a gas introduced into each of the plurality of reaction chambers (71a to 71e) to stir and flow the dehydrated uranyl nitrate. A gas introduction part (78), and a second part for discharging NOx generated in the reaction chambers (71a to 71e).
Flat chamber multi-chamber fluidized reaction bed (70) with NOx discharge (79)
The uranyl nitrate denitration apparatus according to claim 1, wherein 4. The denitration apparatus according to claim 1, wherein
A method for denitrifying uranyl nitrate using a device, comprising the steps of: preparing a solid uranyl nitrate hydrate (1) containing trihydrate to hexahydrate under pressure of 0.01 to 10 mmHg for 30 to 1;
Vacuum dehydration step (2) of placing in an atmosphere having a continuous temperature distribution within the range of 50 ° C. and heating in this atmosphere to obtain dehydrated uranyl nitrate (6) containing dihydrate or less hydrate (2)
And converting the dehydrated uranyl nitrate (6) into an atmosphere having a continuous temperature distribution within a range of 150 to 350 ° C. and heating the atmosphere to convert the uranyl nitrate to UO ₃ and simultaneously obtain NOx having a low moisture content. (3) and only contains the vacuum dehydration step (2), the weight of the heated uranyl nitrate hydrate (6) is measured, and controlling the heating condition in accordance with the weight change rate Denitration method of uranyl nitrate.