JPH1152095A - Device and method for separating waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste-separating technique that can surely exhaust a low-density molten layer outside a system, and ensures the separation of the low-density molten layer and a high-density one. SOLUTION: This device has a crucible 21 consisting of a coil 22 that also serves as an upper crucible, and a lower crucible 23, a multiple helical coil 30, a material supplying device 40, a drawing-out device 50, a non-contacting auxiliary heater 60 and a static magnetic field generator 70. Moreover, a separately take-out passage 27 that has an open cross-sectional structure to force a low-density molten layer M1 to flow outside is installed in a position including an upper free surface M1 ' of the low-density molten layer M1 on a side of the coil 22 that also serves the upper crucible, and a flow regulating member 28 is placed in a position including the upper free surface M1 ' inside the coil 22 that also serves as the upper crucible. The flow regulating member 28 has a self-cooling function of preventing a waste 41 supplied to the low-density molten layer M1 from flowing out directly to the branch passage 27. Consequently, the waste 41 is separated into melts while the separation of the low-density molten layer M1 and a high-density molten layer M2 and the continuous exhaust of the former outside a system are surely carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for reducing the volume of contaminated waste consisting of oxides, nitrides or carbides and metals, separating metals from oxides, nitrides or carbides,
Furthermore, the present invention relates to a waste separation device and a separation method for fixing each separated waste.

[0002]

2. Description of the Related Art Contaminated waste consisting mainly of solidified oxides, nitrides or carbides (hereinafter referred to as "oxides" in the present specification) and metals is mainly melted and subjected to volumetric melting. As a device that performs processing while reducing emissions, U.S.A.
(Retech, Inc. Yukata, California) developed a rotary hearth type plasma melting furnace (PACT), for example, Jour
nal of the RANDEC No. 9 (12, 1993).

FIG. 3 is an explanatory diagram showing the structure of PACT1. As shown in FIG. 1, a PACT 1 includes a steel cylindrical rotary furnace 2 having a discharge port 2a for molten metal and gas at the bottom center, a water-cooled double wall 3 covering the rotary furnace 2, and a plasma torch for igniting an object to be processed. 4. A gas / slag separation chamber 5a and a slag removal chamber 5b installed below the rotary furnace 2, a secondary combustion chamber 6 communicating with the gas / slag separation chamber 5a, and a drum for supplying an object to be processed into the rotary furnace 2. The apparatus includes a feeder 7, a slag container 8 for receiving a melt flowing down the gas / slag separation chamber 5a, and the like.

In operation, a processing object is supplied from the drum feeder 7 into the rotary furnace 2 and the rotary furnace 2 is rotated at about 40 rpm.
The plasma torch 4 is brought close to a ring for initial ignition provided around the discharge port 2a of the rotary furnace 2 to ignite the plasma arc, and the temperature of the furnace increases and the object to be processed is melted. The melted processing object is pressed against the inner furnace wall of the rotary furnace 2 by centrifugal force. By reducing the number of revolutions of the rotary furnace 2 after the completion of the melting, the molten metal is discharged from the discharge port 2a of the rotary furnace 2.
From the slag container 8 via the gas / slag separation chamber 5a
And cooled and collected as a solid.

[0005] As described above, the PACT 1 is a melting furnace in which an object to be processed is charged into the rotary furnace 2, a plasma arc is generated, and the object to be processed is melted to reduce the volume. It can be uniformly stirred to act on the processing target in a molten state, and the obtained solid has uniform and stable properties, has a high degree of freedom regarding the form of the processing target, and rotates the rotary furnace 2. Since tapping is performed by adjusting the number, a complicated mechanism such as a special valve mechanism or a tilting mechanism of the furnace is not required.

However, when the object to be treated is contaminated waste, in particular, radioactively contaminated waste, the PA
The use of CT1 causes the following problems (1) to (3).

(1) Since refractory is used for the lining of the rotary furnace 2, thermal damage is inevitably generated, so it is necessary to periodically replace the lining. In particular, when the object to be treated is radioactively contaminated waste, the used refractory generated at the time of lining replacement also becomes secondary contaminated waste, so that it is necessary to dispose it in another process.

(2) Since a carrier gas such as Ar gas is supplied to the plasma torch 4 due to the necessity of generating a plasma arc, it is necessary to increase the size of the exhaust gas treatment equipment, and the gas is lost as sensible heat of the gas. Energy consumption is large and energy efficiency is low.

(3) Since the plasma torch 4 is a consumable, it needs to be replaced periodically. Especially when the object to be treated is radioactively contaminated waste, the replacement operation of the plasma torch 4 is performed. Need to be performed remotely, which complicates the apparatus.

As an apparatus capable of solving these problems (1) to (3) and treating contaminated waste, the present inventors have previously described "layer separation" described in JP-A-8-120356.・ Phase change device ”. FIG. 4 is an explanatory diagram showing the configuration of the layer separation / phase change device 10 according to this proposal.

As shown in FIG. 1, a layer separation / phase change apparatus 10 according to this proposal has an upper crucible 11 and a lower crucible 11 having a hollow cylindrical shape having the same inner diameter and having flow channels 11a and 12a disposed therearound. 12 are vertically spaced apart from each other to form a hollow column-shaped crucible having a self-cooling function. Upper crucible
A fraction pipe 13 communicating with the upper crucible 11 and having a flowing water channel 13a around the periphery is connected to a substantially central portion in the height direction of the column 11. Furthermore, induction coils 14, 15 to which high-frequency current is supplied from high-frequency oscillators 16, 17 are wound and mounted substantially over the entire length of the upper crucible 11 in the height direction and substantially above the center in the height direction of the lower crucible 12. You.

First, a cylindrical base material M having substantially the same outer diameter as the inner diameter of the lower crucible 12 is inserted into the lower crucible 12, and contaminated from a vibration feeder 18 installed above the upper crucible 11. The waste is put into the upper part of the base material M via the upper crucible 11. When a high-frequency current is supplied to the induction coils 14 and 15, the base material M is induction-heated by the induction coil 15 to form a dome-shaped molten metal pool P on which electromagnetic stirring is performed. Since the thrown waste is in contact with the molten metal pool P, it is heated and melted by the amount of heat from the molten metal pool P, and is further induction-heated by the induction coil 14 as the temperature rises and melted and stirred.

Thus, the waste is separated into an upper layer: a low-density molten layer 19a (oxide etc.) and a lower layer: a high-density molten layer 19b (metal) according to the density by gravity. The separated high-density molten layer 19b moves downward together with the base material M that is pulled downward, and is cooled at a portion where the induction coil 15 is not wound to be a high-density solidified body and pulled out of the lower crucible 12 outside. . On the other hand, the separated low-density molten layer 19a is
It is discharged to the outside of the layer separation / phase change device 10 through 13 and then cooled to a low-density solid.

As described above, the layer separation / phase change device 10
The low-density molten layer 19a is formed by melting the waste in cylindrical crucibles 11 and 12 installed in a substantially vertical direction, utilizing the difference in the density of each of the metal and oxide constituting the waste. , Separated into a high-density molten layer 19b and a low-density molten layer 19a.
Is discharged from the sorting tube 13 to obtain a low-density solidified body.

In particular, in the layer separation / phase change apparatus 10 according to this proposal, the Joule heat generated in the high-density molten layer 19b is propagated to the low-density molten layer 19a by conduction heat transfer, and
It is intended to promote the melting of 19a, and is also excellent in energy efficiency.

[0016]

SUMMARY OF THE INVENTION The present inventors have conducted further studies with the aim of further improving the performance and efficiency of the layer separation / phase change device 10 proposed in Japanese Patent Application Laid-Open No. 8-120356. It has been newly found that the device 10 has the following problems (i) and (ii).

(I) When the low-density molten layer 19a is taken out through the fractionating tube 13 having the surrounding water channel 13a, the low-density molten layer 19a is rapidly cooled and solidified inside the fractionating tube 13, There is a risk that the low-density molten layer 19a may not be able to be taken out to the outside by closing the fractionation tube 13.

(Ii) Upper free surface 19a 'of low-density molten layer 19a
Due to the temperature drop in the vicinity and the instability of the shape of the interface 19c between the low-density molten layer 19a and the high-density molten layer 19b, part of the low-density molten layer 19a is once again separated into the separated high-density molten layer 19b. There is a possibility that the high-density molten layer 19b and the low-density molten layer 19a cannot be reliably separated from each other.

[0019] These problems are extremely serious in practical use in which the essential effect of the layer separation / phase change device 10 proposed in Japanese Patent Application Laid-Open No. 8-120356 is diminished, and it is necessary to take fundamental measures. .

Here, the object of the present invention is to
Solving the new problems inherent in the layer separation and phase change device proposed by JP 56, reliably discharging the low-density molten layer out of the system and ensuring the separation between the low-density molten layer and the high-density molten layer It is to provide a waste separation technology that can be carried out at the same time.

[0021]

SUMMARY OF THE INVENTION The present invention is directed to a crucible having a self-cooling function in the form of a hollow column into which contaminated waste is inserted in a vertical position, and heating the charged waste. A heating mechanism for forming a plurality of molten layers having different densities in the crucible, a waste separation apparatus for separating waste into a plurality of melts, wherein the side surface of the crucible and the At the position including the upper free surface of the low-density molten layer located at the uppermost part, a sorting path having an open cross-sectional structure that allows the low-density molten layer to flow out of the crucible is attached, and inside the crucible, A rectifying member having a self-cooling function for preventing waste supplied to the low-density molten layer from flowing directly to the sorting path is disposed at a position including the upper free surface of the high-density molten layer. And

In the above-described waste separation apparatus according to the present invention, the heating mechanism includes a first induction heating mechanism for induction-heating an area where the low-density molten layer is formed, and a high-density heating section below the low-density molten layer. And a second induction heating mechanism for induction heating the range in which the molten layer is formed.

The waste separation apparatus according to the present invention may further include a non-contact auxiliary heating device which is provided above the crucible and is spaced apart from the crucible to heat the upper free surface of the low-density molten layer. It is desirable to increase the speed.

The above-described waste separation apparatus according to the present invention may further include a static magnetic field generation device which is installed at a distance from the periphery of the crucible and suppresses movement of the low-density molten layer and the high-density molten layer. It is desirable to reliably separate the low-density molten layer and the high-density molten layer.

From another viewpoint, the present invention relates to a method of charging contaminated waste into a vertically arranged hollow column-shaped crucible having a self-cooling function, and heating and melting the waste. A waste separation method for separating waste into a plurality of melts by forming a plurality of melt layers having different densities in a crucible, wherein the low-density melt positioned at the top of the plurality of melt layers is provided. The layer is discharged to the outside of the crucible through an open-section type sorting channel provided at a position including the upper free surface.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a waste separation apparatus and a separation method according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a vertical explanatory view showing the structure of a waste separation apparatus 20 according to the present embodiment. FIG. 2 is a view in which main parts of the waste separation apparatus 20 are extracted and partly broken. FIG.

The waste separation device 20 includes a crucible 21 for containing and melting the waste therein, a multiple spiral coil 30 for applying a high-frequency current to the waste contained in the crucible 21, and a waste in the crucible 21. The main components are a material supply device 40 for supplying 41 and a drawing device 50 for drawing the high-density solidified body downward.
Hereinafter, these components will be described separately.

[Crucible 21] In the present embodiment, the crucible 21
It is composed of a coil (hereinafter, also referred to as an “upper crucible / coil”) 22 and a lower crucible 23 which are arranged along the direction in which gravity acts (vertical direction) and also serve as an upper crucible. Both the upper crucible / coil 22 and the lower crucible 23 have a hollow cylindrical shape having the same inner diameter, and the upper opening of the upper crucible / coil 22 forms an inlet 22a and the lower opening forms an outlet 22b. The upper opening of the lower crucible 23 is the entrance 23
a and the lower opening forms an outlet 23b, each of which is arranged vertically in series.

In the present embodiment, the outlet 22b of the upper crucible / coil 22 and the inlet 23a of the lower crucible 23 are directly connected by appropriate means to form the crucible 21, but the upper crucible / coil 22
For example, a hollow cylindrical insulating wall may be interposed between the outlet 22b of the lower crucible 23 and the inlet 23a of the lower crucible 23 so as to be connected indirectly.

In the present embodiment, as shown in FIG. 2, the wall surface of the upper crucible / coil 22 has an outer peripheral surface of a conductive winding plate 24 having an insulating slit only at one place substantially along the direction in which gravity acts. The surface is formed by welding a water-cooled tube 25 bent in a reciprocating manner. A high-frequency power supply 24 ′ is connected to the winding plate 24 so that an alternating current of approximately 0.05 to 5000 kHz can be supplied in a substantially horizontal plane in the upper crucible / coil 22. Thus, in the above crucible combined coil 22, the low-density melt layer M ₁ is formed.

Note that a coil that also serves as an upper crucible other than this embodiment
The structure of 22 can be exemplified by a structure in which a water-cooled tube is used as a terminal by spirally winding a hollow water-cooled tube with almost no gap and stacking the layers in a stacked manner. Alternating current is passed directly. Regardless of the structure, it is also used as an upper crucible having a self-cooling function in the form of a hollow column, which can be arranged vertically to insert the polluted waste inside and to apply an alternating current to the waste inside. A coil 22 is configured.

The inlet 22 of the wall of the upper crucible / coil 22
The second outlet 26 is formed in a part including a by cutting out a part of the winding plate 24 into a substantially rectangular shape. This second exit
26 is a low density outlet melt layer M ₁ as described later, the base of the second outlet 26 is positioned lower than the upper free surface of the low-density melt layer M ₁ present in the upper crucible combined coil 22 It is formed so that

The opening area of the second outlet 26, to the extent that it is possible to exceed the maximum rate of formation of the low-density melt layer M ₁ which is formed in the upper crucible combined coil 22 discharge rate, is set. Further, the shape of the second outlet 26 is substantially rectangular in the present embodiment, but is not limited to such a shape, and may be an arc shape,
Deformation such as a polygonal shape is possible.

On the outer surface of the second outlet 26, a sorting path 27 is fixed by appropriate means. The preparative path 27 is a discharge passage for causing the outflow flowing out through the second outlet 26 of the low-density melt layer M ₁ to the outside, is no gap connected and fixed to the opening of the second outlet 26.

The sorting path 27 has an open cross-sectional structure having a groove-shaped cross section with an open top. Accordingly, clogging due to coagulation and the coagulated low density melt layer M ₁ is prevented in preparative channel 27, can be reliably and continuously discharged to the outside of the lower density molten layer M _1.

In order to discharge the low-density molten layer M ₁ in the interior, it is desirable that the sorting path 27 is arranged to be inclined downward. Further, in the present embodiment, the cross-sectional shape of the sorting path 27 is a groove shape, but is not limited to such a mode, and the same deformation as the opening shape of the second outlet 26 is possible.

In this embodiment, the second outlet 26 and the sorting path
The low-density molten layer M ₁ formed in the upper crucible / coil 22 flows out from the upper free surface M ₁ ′ side to the outside through 27 and is discharged.

Further, inside the upper crucible / coil 22 and in the vicinity of the second outlet 26, a cooling wall 28 supported by appropriate support means (not shown) is arranged as a baffle plate which is an example of a rectifying member. You. Cold wall 28 is suppressed so that thermal damage is minimized by the contact with the low-density melt layer M ₁ by the self-cooling (not shown), this cooling wall 28, an inlet 22a and second outlet 26 is partitioned Is done.

The cooling wall 28 has a distance from the second outlet 26 to the upper free surface M ₁ ′ of the low-density molten layer M ₁ , which is slightly smaller than the minimum particle size of the waste 41 supplied from the material supply device 40 described later. Only at a height that includes the upper free surface M ₁ ′ of the low-density molten layer M ₁ . Thereby, the low-density molten layer M ₁
Is prevented from floating directly from the second outlet 26 by floating on the upper free surface M ₁ ′ of the low-density molten layer M ₁ .

The self-cooling function of the cooling wall 28 is as follows.
For example, a structure in which a flow path in which cooling water circulates is embedded can be exemplified. On the other hand, the wall surface of the lower crucible 23 has a slit having an insulating function along the direction in which gravity acts (vertical direction).
29a is provided in a predetermined range (in the present embodiment, a range of about 4/5 of the entire length of the lower crucible 23 from the upper end of the lower crucible 23 downward).
Are connected in a circumferential shape. A water cooling pipe 29c is embedded in each segment 29b, and is configured to be able to cool each segment 29b.

As described above, in the present embodiment, the upper crucible / coil 22 and the lower crucible 23 provide a self-cooling function in the form of a hollow cylinder into which the waste 41 that is vertically arranged and into which contaminated waste 41 is inserted is inserted. Having a crucible 21.

[Multiple spiral coil 30] Further, a range corresponding to the middle from the upper end of the lower crucible 23 (in the present embodiment, about 2/2 of the total length of the lower crucible 23 from the upper end side of the lower crucible 23 downward). Three
The outer surface of the
Are arranged in a stacked state. This range is a range in which a high density melt layer M ₂ is formed. That is, the lower crucible 23
The stacking height of the multiple spiral coil 30 is set shorter than the height of the spiral coil 30.

The multiple spiral coil 30 has a high frequency power supply 3
0 'is connected, and a high-frequency current having a frequency of about 0.1 to 100 kHz is supplied to the multiple spiral coil 30 to heat the base material M disposed inside the lower crucible 23 by induction heating.
It is possible to form a high density melt layer M ₂ of the upper.

As described above, in the present embodiment, the high-frequency current is supplied from the high-frequency power source 30 ′ and the high-density molten layer M ₂ is supplied.
Helical coil 30 forming a low-density molten layer M ₁ supplied with a high-frequency current from a high-frequency power supply 24 ′
24 constitutes a heating mechanism 31.

[Material Supply Apparatus 40] A material supply apparatus 40 for supplying the waste 41 into the upper crucible / coil 22 is provided above and separated from the upper crucible / coil 22. The material supply device 40 is not limited to a specific device as long as it can supply a waste 41 adjusted to an appropriate size. For example, a vibration feeder can be exemplified.

[0047] Below the [withdrawal device 50 'under the crucible 23, a high-density solidified and the base material M, which is inserted under the crucible 23, high-density melt layer M ₂ to the base material M is formed by adhesion A removal device 50 for removing the body is provided. This drawing device 50
Is composed of a pair of drive rollers 51a and 51b which are arranged at a distance substantially equal to the outer diameter of the base material M.

The waste separation apparatus 20 of the present embodiment is configured as described above. Although not shown, the waste separation apparatus 20 is provided with a chamber capable of heating, depressurizing, or adjusting the pressure of the portion in contact with the high-density molten layer M ₂ and the low-density molten layer M ₁ to an atmospheric gas such as Ar. It may be accommodated inside.

Further, in the waste separation apparatus 20 of this embodiment, in addition to these main elements, a non-contact auxiliary heating device 60 and a static magnetic field generator 70 are provided as optional elements. Hereinafter, these will also be described.

[Non-contact auxiliary heating device 60] Upper crucible / coil
Above the inlet 22a of the nozzle 22, a non-contact auxiliary heating device 60 is arranged at a certain distance. This non-contact auxiliary heating device
60, depending on the type of waste 41 may lower density molten layer M ₁ itself can not generate sufficient Joule heat to melt the waste 41 is heated in the auxiliary non-contact in such cases Te in order to reliably form a low-density melt layer M _1, is used.

In this embodiment, the non-contact auxiliary heating device 60 using plasma is used. However, any device capable of heating the low-density molten layer M ₁ in a non-contact state may be used. Or radiant heating or the like.

[Static Magnetic Field Generating Apparatus 70]
A static magnetic field generating coil 18 as a static magnetic field generator is arranged. That is, when a high-frequency alternating current is supplied to the winding plate 24 and the multiple spiral coil 30, the low-density molten material M
_Although it is advantageous in promoting the heating of ( ₁₎ , sparks and power supply loss due to high voltage are inevitable. In such a case, a relatively low frequency AC voltage is supplied,
Now electromagnetic stirring becomes remarkable, both become difficult to maintain the interface between the low-density melt layer M ₁ and the high density melt layer M ₂ stably is likely to be mixed.

Therefore, in particular, at the boundary between the low-density molten layer M ₁ and the high-density molten M ₂ , the low-density molten layer M ₁ and the high-density molten static magnetic field generating coils 70 in effect of suppressing the movement of the liquid metal, such as layer M _2, for example by using a superconducting magnet, to stabilize the boundary surface.

Next, the volume reduction of the contaminated waste 41, the phase separation between the metal and the oxide, and the fixing of each of the wastes 41 by the waste separation apparatus 20 of this embodiment will be described with time.

First, the upper crucible / coil 22, the lower crucible 23,
Cooling water is supplied to a portion to be heated such as the multiple spiral coil 30 to keep it in a predetermined cooling state. Further, when the waste separation device 20 is accommodated in the above-described chamber, the contact portion between the high-density molten layer M ₂ and the low-density molten layer M ₁ is adjusted to an atmospheric gas such as pressurized, depressurized, or Ar. Keep it.

In this state, the base material M which is a columnar metal having an outer diameter substantially equal to the inner diameter of the lower crucible 23 is inserted into the lower crucible 23 from the outlet 23b. Insertion of the base material M is performed until the tip of the lower crucible 23 reaches the inlet 23a of the lower crucible 23.

After inserting the base material M into the lower crucible 23, the waste 41 is charged from the material supply device 40 into the upper crucible / coil 22.
A predetermined amount is charged onto the base material M. The waste 41 is generally a mixture of a metal and an oxide, but is not a single phase, and a waste in which a reduction reaction or the like proceeds in a melting process to obtain a metal, or a case where the reduction reaction does not proceed. Can be used a waste from which a mixture of a metal and an oxide is obtained.
Further, if necessary, auxiliary materials such as a reducing agent, a reducing gas or an oxidizing gas may be charged together with the waste 41.

In this way, preparations for waste treatment are made, and a high-frequency current is supplied to the upper crucible / coil 22 and the multiple spiral coil 30, respectively. Then, the first base material M is induction heating, the upper portion to form a high density melt layer M ₂ are melted, the high density melt layer M ₂ by the action of electromagnetic force and gravity is raised in a dome shape.

The high-density molten layer M ₂ is further heated by induction heating, and the waste 41 existing above the high-density molten layer M ₂ is heated.
Is heated and melted by conduction heat transfer. When heating of the waste 41 is made, in particular, ions low density electric conductivity of the molten layer M ₁ is increased play a major role in the electrical conductivity, also the line induction heating by the upper crucible serves coil 22 waste 41 eventually The temperature rises more markedly. With this, the upper crucible combined coil
A low-density molten layer M ₁ is formed inside 22.

That is, the waste separation apparatus 20 of the present embodiment
Then, in order to form a high-frequency electromagnetic field, the base material (metal) M which is melted by applying an electromagnetic force to the base material (metal) M gathers at the center of the crucible 21 and generates Joule heat. When the base material M is further melted by this Joule heat to form a high-density molten layer M ₂ , the high-density molten layer M ₂ rises in a dome shape due to electromagnetic force and gravity, and the crucible 21 A non-contact area appears. If you choose the right frequency,
Such an effect acting on the base material M can be made larger than an effect acting on the oxide. In this way,
In the initial stage of melting when the oxide is not melted, the oxide coexists with the base material M in the crucible 21, and the oxide conducts from the heated and melted base material M, rather than being heated by induction heating. The temperature is increased by heat transfer.

In general, an unmelted skull layer may adhere to a portion in contact with the low-density molten layer M ₁ and may remain in the lower crucible 23. Since this skull layer is a kind of sintered layer and has insufficient fixation of radionuclides, it is necessary to surely prevent the skull layer from flowing out of the system. In waste separation device 20 of the present embodiment, the high density melt layer M ₂ is for receiving the induction heating, promotes the heating of the surrounding low-density melt layer M _1. Therefore, since the skull layer skull layer when approaching the high density melt layer M ₂ side existing below is melted, the base material M
Will not be discharged out of the system when it is pulled down.

In a region below the region where the slit 29a is formed in the lower crucible 23, the base material M
No induction heating is performed. Therefore, the high-density molten layer M ₂
The cooled solidified high density melt layer M ₂ is a high-density solid material.

After the waste 41 is formed into the low-density molten layer M ₁ , the high-density molten layer M ₂ and the high-density solidified body in the crucible 21 in this way, the waste
With charged waste 41 from a material supply device 40 to the present in the inlet 22a side low-density melt layer M ₁ of the free surface,
High density melt layer M ₂ and the low density molten layer M ₁ of each interface, at a drawing speed to maintain a constant height, further withdrawal of the preform M downwards.

[0064] Thus, the high-density solid material from the outlet 23b of the lower crucible 23 is continuously withdrawn, the low-density melt layer M ₁ from preparative passage 26 of the upper crucible combined coil 22 is discharged out of the system. Discharged low-density melt layer M ₁ is cooled is housed in the housing container (not shown), eventually the low density solid material.

As described above, the waste separation apparatus of the present embodiment
In Example 20, since the density of the oxide is smaller than that of the metal, the oxide outlet and the metal outlet are provided at portions where the height of the crucible is different. it can be performed _first and isolation of the high density melt layer M _2. In the present embodiment, the molten metal melted in the furnace (high-density molten layer M ₂ ) or the molten metal supplied in the furnace (high-density molten layer M ₂ ) is directed in the direction in which gravity acts (vertically downward direction). ), And is cooled and solidified by the portion of the lower crucible 23 where the multiple spiral coil 30 is not provided, and is discharged from the first outlet 23b to the outside of the system. On the other hand, the oxide (low-density molten layer M ₁ ) is discharged out of the system from a second outlet 26 provided in the upper crucible / coil 22.

According to the waste separation apparatus 20 of the present embodiment,
The wall surface of the crucible 21 and the cooling plate 28 are not formed of a refractory constituting a high-temperature wall furnace of a normal induction melting furnace, but are formed by cooling walls having a self-cooling function. Thereby, even if the waste 41 is dissolved, there is almost no heat damage,
The eroded furnace wall does not become new waste. Especially,
If the waste 41 is a radioactively contaminated material, the furnace wall material does not become secondary waste, so that the life is long and no radioactive secondary waste is generated (effect 1).

[0067] In the waste separation device 20 of the present embodiment, the crucible 21, a first outlet 23b for discharging the high-density solid material with base material M, a second outlet 26 for discharging the low density molten layer M ₁ Are provided. When the unmelted oxide approaches the first outlet 23b, melting is performed by conduction heat transfer from the molten metal. On the other hand, the discharge of the unmelted waste 41 out of the system from the second outlet 26 means that the volume reduction and fixing treatment of the waste 41 are not sufficient and the device is incomplete as a unit. In the waste separation apparatus 20 of the embodiment, since the cooling plate 28 is installed, the unmelted oxide (waste) is prevented from flowing directly to the sorting path 27, and the second outlet 26 is for placement in the vicinity of the low density of the free surface melt layer M _1, for example, it becomes possible to use a non-contact auxiliary heating device 60 using plasma or the like, it is possible to complete melting of the oxide. Since non-contact heating is an auxiliary means of heating, even if plasma is used, the amount of carrier gas can be remarkably reduced as compared with the conventional case. As described above, according to the waste separation apparatus 20 of the present embodiment, after the waste is melted, it can be reliably separated into oxides and metals and taken out (effect 2).

In the waste separation apparatus 20 of the present embodiment, the high-density molten layer M ₂ separated from the waste 41 melted by the induction heating is cooled while the base material M is pulled down and cooled. It becomes a solidified material and is continuously taken out of the system from the first outlet 23b. On the other hand, the low-density molten layer M ₁
Is continuously discharged out of the system through a second outlet 26 provided in the upper crucible / coil 22 and is not a channel surrounded by a cooling wall as in the device described in JP-A-8-120356. Since the liquid is guided to the outside through the sorting passage having a cross-sectional structure, there is no possibility of blockage in the flow passage. Therefore, according to the waste separation device 20 of the present embodiment, a series of waste treatment can be continuously performed. Continuous process low-density melt layer M ₁ and the high density melt layer M ₂ each in the rate of advancement of the solidification interface can be kept constant because it is possible, low density solid material enhances the quality of the respective dense solidified be able to. Further, since continuous processing is possible, it is possible to omit the time required to raise and lower the temperature of the furnace as in, for example, batch processing, and to reduce the size of the furnace compared to a conventional furnace if the processing capacity is the same. it can.
In this way, according to the waste separation apparatus 20 of the present embodiment, the quality of each of the high-density solidified body and the low-density solidified body can be improved and the size of the apparatus can be reduced (effect 3).

Further, in the waste separation apparatus 20 of the present embodiment, when a high-frequency range in which electromagnetic stirring is remarkable is selected in order to promote a reaction in the furnace, the low-density molten layer M ₁ and the at the boundary between the high density melt layer M _2, it is necessary to suppress mixing of the two phases due to the interface of the disturbance, the static magnetic field generating device for, for example, a superconducting magnet disposed on the outer surface of the crucible 21, the liquid Suppress metal movement. In this way, it is possible to realize a reliable separation of low-density melt layer M ₁ and the high density melt layer M ₂ (Effect 4).

As described above, according to the waste separation apparatus 20 of this embodiment, the low-density molten layer M ₁ is reliably and continuously discharged out of the system, and the low-density molten layer M ₁ it can be reliably separated with the molten layer M _2.

[0071]

EXAMPLES Further, the waste separation apparatus according to the present invention will be described more specifically with reference to practical data.

(First Embodiment) The waste 41 was separated using the waste separation apparatus 20 according to the present invention having the structure shown in FIG. The specifications of the waste device 20 were as listed below.

Lower crucible 23: inner diameter 100mm, outer diameter 150mm, height 250mm, material copper Slit 29a: slit length 180mm, number of slits 20, slit gap 0.2mm Multiple spiral coil 30: coil pipe inner diameter 15mm, wall thickness 1mm, Lower crucible 23 / coil gap 5mm, stacking height 100mm, number of turns 5 turns Upper crucible / coil 22: inner diameter 100mm, outer diameter 105mm, height 100mm, material copper, number of slits 1 cooling wall 28: thickness 8mm, high 50 mm in width and 50 mm in width First high frequency power supply 30 ': frequency 100 kHz, output 100 kW Second high frequency power supply 24': frequency 20 kHz, output 150 kW Drawing device 50: maximum drawing speed 50 mm / min High density molten layer M ₂ : density 9 g / cm ³ Low-density molten layer M ₁ : Density 6 g / cm ³ Water-cooled tube 25: Inner diameter of 15 mm In this embodiment, when operating this waste separation device 20, first, an upper crucible / coil 22, a multiple spiral coil
30, cooling wall 28, first high frequency power supply 30 ', second high frequency power supply 2
4 ', 100, 40, 20, 50, 50, 40l for each water cooling tube 25
After supplying cooling water at a flow rate of / min, the coil 2
2 and the lower crucible 23 were adjusted to an Ar gas atmosphere.

Subsequently, from below the lower crucible 23, a length of 200 mm
A base material M made of stainless steel having a diameter of 99 mm was charged until the upper end thereof substantially coincided with the upper end of the lower crucible 23. At this time, the high-density molten layer M from the gap between the base material M and the lower crucible 23
The outer diameter of the base material M was made as close as possible to the inner diameter of the lower crucible 23 in order to prevent the flow down of ₂ .

Then, FP (spent nuclear fuel after reprocessing)
As a simulated spent nuclear fuel, Cr, Fe, Ni, Se, Rb, Sr, Y, Zr, assuming the treatment of spent nuclear fuel after calcination and vaporization of a mixture of Mo,
Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Cs, Ba, L
500 g of an oxide containing a, Ce, Pr, Nd, Sm, Eu, and Gd as main components
And a mixture of 130 g of silicon nitride functioning as a reducing agent were charged onto the base material M from the inlet 22 a of the upper crucible / coil 22.

Multiple spiral coil 30 and coil for upper crucible
22 were supplied with high frequency currents of 1000A and 5000A, respectively. By the action of induction heating and magnetic pressure, the base material M was melted and raised in a dome shape to form a molten pool P. The depth of the molten pool P was about 80 mm. As a result, in the lower region of about 120 mm, the base material M did not melt and was in a solid state.

As the melting of the base material M progresses, Cr, Fe, Ni, Se, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Id
Each element of n, Sn, Sb, and Te was reduced by silicon nitride and mixed with the molten base material M to form a uniform metal melt (high-density molten layer M ₂ ). While the remaining elements present as oxides, it increases the electrical conductivity was heated by conduction heat transfer from the high density melt layer M _2, eventually, oxide itself is subjected to induction heating, melting and reducing reaction Doo is expanded to the entire interior of the acceleration to stretch the upper crucible combined coil 22, to form a uniform low-density melt layer M _1.

In this state, the high-density molten layer M ₂ reached a temperature of approximately 2000 ° C. At this time, in the region apart than 10mm high density melt layer M ₂ in cooling the wall near the lower crucible 23, it was completely dissolved leaving undissolved layer of an oxide of 1mm thick. It was later found that this oxide layer was sintered and fixed.

After realizing such a state, the waste 41 is removed from above the upper crucible / coil 22 via the material supply device 40.
While supplying at a speed of 500 g / min, the base material M was pulled downward at a speed of 5 mm / min. At this time, the low-density molten layer M ₁ wrapped around the lower end of the cooling wall 28 and was discharged out of the system from the second outlet 27 formed in the upper crucible / coil 22.

The low-density solid that was discharged from the system after cooling and solidified by cooling was vitreous and dark green. In this way, the waste was phase-separated into the form of metal and oxide, and the volume was reduced and fixed by melting and solidifying.

(Second Embodiment) In the first embodiment, an inductively coupled plasma heating device having a maximum output of 50 kW was installed as the non-contact auxiliary heating device 60, and waste 41 containing oxides was treated.

In the first embodiment, the upper limit of the processing speed is 500 g / m
is in, when supplying a large amount of waste increases the more the processing speed, some of the waste 41 is accumulated on the surface layer of low-density melt layer M ₁ remain unmelted. On the other hand, in the case of this example, the processing speed could be increased to 1000 g / min. Thus, by performing the auxiliary heating by installing a non-contact auxiliary heater 60, by forming a low-density melt layer M _1, it was able to double the processing speed.

(Third Embodiment) In the second embodiment, a static magnetic field generating coil having an effective magnetic flux density of 5 T was installed as the static magnetic field generating device 70, and the waste 41 containing oxide was treated.

In the second embodiment, the processing speed could be increased to 1000 g / min. However, a low-density solid (oxide) was mixed in the obtained high-density solid, a molten layer M ₂ the separation of low-density molten layer M ₁ could not be fully performed. In contrast, in the present embodiment, the low density solid material is not mixed, performs perfectly the separation of the high density melt layer M ₂ and the low-density melt layer M ₁ in the dense solidified I was able to. Thus, by installing a static magnetic field generating coil 70, by forming a low-density melt layer M _1, it was possible to reliably perform the separation of the high density melt layer M ₂ and the low-density melt layer M ₁ .

Table 1 summarizes the results of comparing the apparatuses of the first to third embodiments, the conventional method: PACT, and the comparative method: the apparatus described in JP-A-8-120356.

The evaluation items in Table 1 are the continuous processing time (Hr) in which continuous processing was possible until the blockage, the secondary waste generation ratio (%) with respect to the amount of waste processed, and the discharge to the outside of the system. The processing speed at which the unfused oxidized portion contained in the low-density molten layer is exposed becomes the "0.1% unmolten oxide generation limit treatment speed". There are three types of processing speed, "the limit processing speed of 0.1% oxide mixing", which is the processing speed at which the oxidized portion of the melt becomes apparent.

[0087]

[Table 1]

From Table 1, it can be seen that Example 1 was able to reliably separate metals and oxides while significantly reducing the rate of secondary waste generation as compared to the conventional example and the comparative example. I understand. The second embodiment is different from the first embodiment in that
It can be seen that the processing speed could be doubled.

Further, it can be seen that in Example 3, the phase separation was surely performed while maintaining the same processing speed as in Example 2. As described above, according to the first to third embodiments, the volume reduction and the reduction of the volume of the metal including the contaminated oxide and metal, the nitride and the metal, and the waste including the different layers such as the carbide and the metal are performed. Phase separation and fixation of other phases could be performed, and the amount of secondary waste generated could be significantly reduced as compared with the conventional case.

[0090]

As explained in detail above, the present invention is directed to a contaminated waste, particularly a radioactively contaminated waste, in which the phase separation of the melt proceeds in the melting process. (1) The life of the melting furnace is long and no secondary waste is generated. (2) After melting the oxide and metal,
That each can be separated and taken out of the system,
(3) The effects of improving the quality of the solidified body, miniaturizing the device, and (4) realizing phase separation were obtained. The significance of the present invention having such an effect is extremely remarkable.

[Brief description of the drawings]

FIG. 1 is a vertical explanatory view showing a structure of a waste separation apparatus according to an embodiment.

FIG. 2 is a perspective view illustrating a main part of the waste separation apparatus according to the embodiment, which is extracted and partly broken.

FIG. 3 is an explanatory view showing a structure of a rotary hearth type plasma melting furnace PACT.

FIG. 4 is an explanatory diagram showing a configuration of a layer separation / phase change device described in Japanese Patent Application Laid-Open No. 8-120356.

[Explanation of symbols]

20 Waste separation device 21 Crucible 22 Upper crucible combined coil 23 Lower crucible 27 Sorting path 28 Cooling plate (rectifying member) 30 Multiple spiral coil 40 Material supply device 41 Waste 50 Extraction device 60 Non-contact auxiliary heating device 70 Static magnetic field generation device M ₁ low-density molten layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F27B 14/10 C22B 7/00 F F27D 9/00 B09B 3/00 ZAB // C22B 7/00 303K

Claims (5)

[Claims] 1. A crucible having a self-cooling function in the form of a hollow column into which contaminated waste is inserted in a vertical direction, and the charged waste is heated to have a density in the crucible. A heating mechanism for forming a plurality of different molten layers, wherein the waste separation apparatus separates the waste into a plurality of melts, wherein the side surface of the crucible and the most of the plurality of molten layers At a position including the upper free surface of the low-density molten layer located at the top, a sorting path having an open cross-sectional structure for allowing the low-density molten layer to flow out of the crucible is attached, and inside the crucible, A rectifying member having a self-cooling function for preventing the waste supplied to the low-density molten layer from flowing directly to the sorting path is disposed at a position including the free surface. Waste separation equipment. 2. The heating mechanism includes: a first induction heating mechanism for induction-heating a range where the low-density molten layer is formed; and a range where a high-density molten layer below the low-density molten layer is formed. The waste separation apparatus according to claim 1, further comprising a second induction heating mechanism for performing induction heating. 3. The apparatus according to claim 1, further comprising a non-contact auxiliary heating device installed above the crucible at a distance from the crucible to heat the upper free surface of the low-density molten layer.
Or the waste separation device according to claim 2. 4. The apparatus according to claim 1, further comprising: a static magnetic field generator that is installed at a distance around the crucible and that suppresses movement of the low-density molten layer and the high-density molten layer. Item 4. The waste separation device according to any one of items 3 to 3. 5. A contaminated waste is charged into a vertically disposed hollow column-shaped crucible having a self-cooling function, and the waste is heated and melted to have a different density in the crucible. A waste separation method for separating the waste into a plurality of melts by forming a plurality of melt layers, wherein the low-density melt layer located at the top of the plurality of melt layers is A method for separating wastes, wherein the wastes are discharged to the outside of the crucible through a separation passage having an open-section structure provided at a position including an upper free surface.