JPH10332890A - Device for batch dissolution and lumping and method for dissolution and lumping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate an oxide phase and an oxide phase of a contaminated oxide and make it possible to reduce secondary wastes by providing the bottom of a melting crucible with a melt exhaust nozzle whose cross section is uniform, opening only the upper part of a lumping crucible at a lower level and making the cross-sectional area of it smaller and smaller as the bottom is drawing near. SOLUTION: A dissolution crucible 1 has an upper opening 7 and melt exhaust nozzle 8. A solid material to be dissolved is loaded into the dissolution crucible 1 from the upper opening 7 by material supplying devices 15a and 15b, and the material dissolved inside the crucible 1, or a melt phase 11 of metal and a melt phase 12 of an oxide, is exhausted from the exhaust nozzle 8. The cross-sectional area of the dissolution crucible 1 becomes smaller and smaller toward the melt exhaust nozzle 8, but the cross-sectional shape of it is uniform. Then, a metal material containing an oxide and a reducer are poured into the dissolution crucible 1 and are heated by upper and lower induction coils 2 and 3 to be melted, and the melt obtained in the dissolution crucible 1 is exhausted into a lumping crucible 20 and is slowly cooled to extract a solid oxide and metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a spent nuclear fuel,
The present invention relates to a technique for reducing the volume of radioactively contaminated substances such as radioactive waste, and for separating components into a metal phase and an oxide phase to facilitate post-treatment.

[0002]

2. Description of the Related Art Conventionally, a rotary hearth type plasma melting furnace (hereinafter, referred to as "PACT") has been used as an apparatus for reducing the volume of a contaminated amorphous solid by melting.
Is disclosed in Journal of the RANDEC No 9 (12, 1993). PACT supplies an object to be processed to a rotating melting furnace and melts it by a plasma arc, and has the following features.

(1) Since uniform stirring by centrifugal force is possible, a homogeneous and stable property of a molten solid can be obtained.

(2) The degree of freedom for the form of the material is large.

(3) Since tapping is performed by adjusting the number of revolutions, complicated devices such as special valves and tilting of the furnace are not required.

However, when the object to be treated is a material contaminated with a radioactive substance as in the present invention, these methods still have the following problems.

(1) Since a refractory is used for the lining of the melting furnace, the refractory is damaged and requires periodic replacement of the refractory. In particular, when the object is a contaminated material, the refractory generated in the maintenance process becomes secondary waste, which necessitates another treatment.

(2) A carrier gas such as Ar is supplied to a torch to generate a plasma arc. Therefore, it is necessary to increase the size of a waste gas treatment facility containing radioactive materials, The energy lost as sensible heat is large.

(3) Since the plasma torch is a consumable item, it needs to be periodically replaced. In particular, when the target is a material contaminated with radioactive materials, the replacement operation is performed remotely, which complicates the equipment and reduces workability.

The following method has been disclosed to solve the above problems.

Japanese Patent Publication No. 6-45810 discloses an electromagnetic nozzle device attached to the lower end of a batch processing furnace.
This electromagnetic nozzle has a function of taking out a melt that has been melted in a batch processing furnace for an arbitrary time outside the furnace so that the nozzle material is not contaminated. Such an electromagnetic nozzle is effective for metals, but is difficult to use for opening holes when melting oxides such as glass or a mixture of oxides and metals, and for subsequent outflow. This is because the electrical conductivity of the oxide has a remarkable temperature dependency, and
Frequency band 5 × 10 ³ as disclosed in
This is because even if a high frequency of ⁵ Hz to ⁵ × 10 ⁵ Hz is used, the material closed by the water-cooled finger cannot be induced and dissolved.

JP-A-5-15950 discloses a means for continuously or intermittently discharging an appropriate amount of a molten material from a crucible when the material is induced and melted. However, in this method, since there is no mechanical nozzle opening / closing device, the discharge or holding of the melt is performed only by the electromagnetic force acting on the melt. Theoretically, the induced current flows on the ring, so that the ring radius becomes zero at the lowermost end of the melt. This means that no electromagnetic force acts on the melt,
It is considered that the discharge control of the melt is difficult in this method.

Japanese Patent Application Laid-Open No. 7-3346 discloses a magnetic levitation induction melting device. Magnetic levitation is possible when the object to be treated is a metal with high electrical conductivity, but especially when melting oxide such as glass, the frequency required to achieve magnetic levitation Is high and inevitably becomes a high voltage, and as a result, a spark is generated, which is difficult to implement.

[0014]

SUMMARY OF THE INVENTION The object of the present invention is to provide systems which are contaminated, in particular radioactively contaminated, in which the phase separation of the melt proceeds during the melting process. TECHNICAL FIELD The present invention relates to an apparatus and a method for separating separated solids.

Problems required for the apparatus to satisfy this object will be described below. (1) Both metals and oxides can be melted. (2) The melting furnace has a long service life and does not generate secondary waste. (3) The material can be melted for an arbitrary time and discharged out of the system in a short time. (4) Phase separation of the metal phase and the oxide phase can be performed.

[0016]

As a method for dissolving a mixture of a metal and an oxide, there is a method using plasma or an electron beam. However, plasma is difficult to process with a carrier gas, and an electron beam complicates a device for maintaining a high vacuum. In addition, workability is reduced because maintenance of the device is performed remotely.

The present inventors have conducted various experiments and studied, and as a result, have obtained the following findings. (1) When a reducing agent is added to a mixture of an oxide and a metal, the metal is increased by smelting reduction. As a result, the metal receives the pinch force (interaction with the magnetic field created by the electric current) and gathers at the center of the melting crucible. At the same time, the magnetic field is completely shielded. Heat can be generated. For this reason, the oxide existing between the metal and the melting crucible wall not only undergoes induction heating, but also undergoes normal skull melting (solidification and solidification of the melt in contact with the cooling wall) due to heat conduction and radiant heat transfer from the metal. In this case, the temperature is higher than in the case where the melting is performed in a state where the heat insulating layer is formed in the self-flying, the skull layer becomes thinner, and the shape of the molten pool becomes similar to the shape of the melting crucible. In addition, the electromagnetic stirring increases the symmetry of the velocity field, and enables stable dissolution.

(2) The melting crucible is made of water-coolable copper without using a refractory material. If an induction coil is wound around the periphery, a skull layer is formed, and induction melting is performed in the melting coil. Is almost unnecessary. Even if the skull layer is peeled off, the skull enters the lower ingot crucible and solidifies in a state surrounded by the melt, so that no problem occurs.
For this reason, especially in the case of materials contaminated with radioactivity, the melting crucible does not become secondary waste.

(3) When the composition of the melt is composed of a large number of chemical elements, a batch processing method is indispensable. This is because, in the continuous processing method, since a melt having a large specific gravity and a low melting point is preferentially discharged, there is a problem that the properties of the solid are not uniform. In order to solve this problem, a technique for completely closing the discharge port and opening the discharge port in a short time when necessary is required. To this end, this problem can be solved by using a batch processing method in which low-temperature fingers and high-temperature fingers are appropriately used.

Here, the "low temperature finger" has a function of promoting solidification of the melt and preventing the melt from being discharged from the melting crucible to the outside of the system. The "high-temperature finger" is one that promotes melting of the oxide at the bottom of the melting crucible by induction heating and can provide an opening necessary for discharging from the bottom of the melting crucible in a short time.

(4) When the discharged melt is put into an ingot crucible, a solid separated into a metal phase and an oxide phase by specific gravity separation is obtained, and the shape of the crucible is such that the top opening is larger than the cross-sectional area of the bottom. If it is, the solid can be easily taken out simply by inverting the ingot crucible.

The present invention has been made based on such findings, and the gist is as follows (A) to (C).

(A) A chamber capable of adjusting the internal atmosphere and provided with a material supply means for supplying a molten material to an upper portion, a melting crucible provided with an induction coil on an outer periphery provided in an upper part of the chamber, A batch melting and ingot making apparatus having an ingot crucible provided in the lower part of the inside of the chamber, wherein the lower part of the melting part of the upper melting crucible has a smaller cross-sectional area toward the lower part, and is insulated from each other. It is composed of a plurality of segments that can be cooled and has a melt discharge nozzle with a constant cross-sectional shape at the bottom of the melting crucible, the lower stage ingot crucible is open only at the top,
A batch type melting and agglomeration apparatus, wherein the cross-sectional area decreases from the top to the bottom.

(B) The batch melting crucible according to the above (A), wherein the ingot crucible is constituted by a cooling structure having a slit in a vertical direction, and an induction coil is provided on the outer periphery. apparatus.

(C) A metal material containing an oxide and a reducing agent are charged into a melting crucible and heated and melted. The melt obtained in the melting crucible is discharged into an ingot crucible, and gradually cooled to form an oxide and a metal. A batch-type melting and agglomeration method using the apparatus according to any of the above (A) or (B), wherein the solid is taken out.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below based on a schematic longitudinal sectional view of an apparatus showing an outline of an example of the present invention shown in FIG. FIGS. 2A and 2B are schematic diagrams in which the insulating slit portions 9 and 10 of the melting crucible 1 and the ingot crucible 20 of FIG. 1 are partially enlarged. FIG. 4 is a schematic longitudinal sectional view when the induction coil 25 is used for the ingot crucible 20 of FIG.

The parts that come into contact with the molten raw material, for example, the melting crucible 1 and the ingot crucible 20 are housed in an atmosphere chamber 17 so that contaminants do not leak to the periphery. Also,
The atmosphere chamber 17 is provided with an auxiliary device for adjusting the atmosphere of the deaeration port 16 and the inert gas supply port 18.

The entire device is a melting crucible 1 arranged vertically
The melting crucible 1 has an upper opening 7 and a melt discharge nozzle 8. From the upper opening 7, solid material is charged into the melting crucible 1 by the material supply devices 15a and 15b, and from the melt discharge nozzle 8, the material melted in the melting crucible 1, that is, The molten phase 11 of the metal and the molten phase 12 of the oxide are discharged.

Although the cross-sectional area of the melting crucible 1 decreases toward the melt discharge nozzle 8, the cross-sectional shape of the melt discharge nozzle 8 is constant. In a portion where the cross-sectional area is reduced, heating and subsequent melting and reduction of the material are mainly performed, and in a certain portion, the material has a function as a nozzle of the melting crucible 1. Therefore, as long as it has two functions of a heating, melting, and reducing section (hereinafter, referred to as a melting section) and a melt discharge nozzle, it is not necessarily limited to the melting crucible having the shape shown in FIG. However, in order to prevent the melt from flowing out of the system from the gap between the melting part and the nozzle part, a structure in which the two are generally connected is desirable. That is, it is preferable that the melting part and the melt discharge nozzle 8 have a structure connected vertically.

As shown in FIG. 2A, the melting crucible 1 is provided with an insulating slit 9 having an insulating function (the insulator is mica or the like) in a predetermined section along the longitudinal direction. That is,
The wall of the melting crucible 1 is divided into segments, and each segment has a structure that can be cooled.

At least two types of upper induction coils 2 and lower induction coils 3 are wound around the outer periphery of the melting crucible 1 with a certain gap from the crucible, and the upper induction coils 2 and 3 are configured to be water-cooled. ing. The upper induction coil 2 is used for heating, melting and reducing the material, and the lower induction coil 3 is used for controlling the discharge of the melt.

A part of the material supplied from the material supply devices 15a and 15b undergoes a chemical reaction (reduction reaction) in the melting crucible 1 to form a material having high electric conductivity such as a metal from the oxide material.

A high-temperature finger 14a and a low-temperature finger 14b can be inserted inside the melt discharge nozzle 8. When the high-temperature finger 14a is inserted into the melt discharge nozzle 8 and the lower induction coil 3 is induction-heated as necessary, it is possible to prevent the melt from adhering to the inner wall of the melt discharge nozzle 8 and solidifying. On the other hand, since the melt discharge nozzle 8 is heated, the melt can be discharged into the ingot crucible 20 in a short time by removing the high-temperature fingers 14a.

The low temperature finger 14b is cooled,
When inserted into the melt discharge nozzle 8, solidification of the melt at the bottom in the melting crucible 1 is promoted, and the discharge of the melt from the melt discharge nozzle 8 is prevented.

At the lower end of the melt discharge nozzle 8, there is provided a device (not shown) for inserting a high-temperature finger and a low-temperature finger into the melt discharge nozzle 8.

The ingot crucible 20 is a crucible having an opening only at the top and a cross-sectional area decreasing from the top to the bottom. In the ingot crucible 20, a crucible material having a small thermal conductivity is selected in order to slowly cool the melt. Also, as shown in FIG. 2B, an insulating slit 10 is provided along the longitudinal direction as necessary, and the periphery thereof is surrounded by an induction coil 25 as shown in FIG. It can also be cooled while performing. Although the cooling means is not shown in FIG.
What is necessary is just to make it the structure according to (a).

Using such an apparatus, volume reduction and phase separation of the material are performed as follows. After closing the melt discharge nozzle 8 with the high-temperature finger 14a, an oxide and a necessary amount of a reducing agent are added to the melting crucible 1. In the initial stage of melting, when the melting crucible contains only an oxide and a reducing agent, a metal (iron, iron alloy, etc.) is also added, and two kinds of melting raw materials are supplied using the material supply devices 15a and 15b. At the same time as the atmosphere of the inert gas, the melting crucible 1 is cooled. Subsequently, a high-frequency current is supplied to the upper induction coil 2 and the lower induction coil 3 of the melting crucible 1. In this state, first, the high-temperature finger 14a is heated by induction heating, and a part of the material at the bottom of the crucible is melted. At this time, heating of the cross-sectional area reduced portion of the melting crucible 1 is not promoted. This is because oxides at room temperature have low electric conductivity and do not receive induction heating. In order to expand the melting to the cross-sectional area reduction portion in a short time, auxiliary heating (plasma, microwave, etc.) may be appropriately performed from the top of the crucible.

Next, when the temperature of the oxide rises and self-heating starts, the supply of the high-frequency current to the lower induction coil 3 of the melting crucible 1 is stopped, so that the high-temperature fingers 14 a
And to prevent the high-temperature fingers 14a from reacting with the oxide. To ensure that the melt discharge nozzle 8 is closed, lower the temperature of the high-temperature finger 14a to form a solidified layer at the upper end of the melt discharge nozzle 8 and confirm that the melt is not discharged. It is preferable to insert the finger 14b.

The temperature in the furnace, particularly in the reduced area of the cross-sectional area, is raised by induction heating, and the oxide starts melting, and the smelting reduction reaction proceeds, and as a result, metal is generated in the melt. As a result of the electromagnetic stirring, the generated metal grows through repeated collisions and receives an electromagnetic pinch force, so this metal becomes a large lump of molten metal and floats almost in the center of the crucible as if it were a pool of oxide. State. Most of the Joule heat is concentrated in the molten metal lump, and the temperature rise and melting of the surrounding oxides are promoted by heat conduction and radiation. The feature of the present invention resides in that oxides can be dissolved at a lower frequency than in the past because such a heat generation phenomenon of the metal occurs.

Oxide has a lower electric conductivity than metal, and therefore generates less Joule heat per unit volume, and a portion in contact with the cooling crucible solidifies to form a so-called skull layer.

At the stage when the smelting reduction reaction reaches saturation, the discharge operation is started. Connect the melt discharge nozzle 8 to the hot finger 14
Power is supplied to the lower induction coil 3 of the melting crucible 1 in exchange for a. When the temperature of the high-temperature finger 14a rises and melting of the furnace bottom progresses, and an opening of a predetermined size is obtained, the high-temperature finger 14a is pulled down and the high-temperature finger 14a is moved to a predetermined place that does not interfere with the path of the discharged hot water. The finger 14a is moved. Thus, the molten metal and the molten oxide are poured into the ingot crucible 20.

The molten material poured into the ingot crucible 20 is gradually cooled to a solid. The cooling rate at this time is important,
It is necessary to maintain the molten state for at least the time required for the specific gravity separation of the metal and the oxide to proceed.
For this purpose, an induction coil 25 for induction heating the ingot crucible 20 is provided as needed. Since the insulated slit 10 having an insulating function is arranged in the ingot crucible 20 as necessary, it is possible to apply a high-frequency electromagnetic field into the ingot crucible 20.

[0043]

EXAMPLES Using the apparatus shown in FIG. 1, the following raw materials were melted and agglomerated. Dissolved raw material is assumed to be a process of spent nuclear fuel after calcination and vaporization of a mixture of FP (spent nuclear fuel after reprocessing) and CP (piping corrosion product),
Cr, Fe, Ni, Se, R as simulated spent nuclear fuel
b, Sr, Y, Zr, 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 was charged into the material supply device 15a.

As a reducing agent, 130 g of silicon nitride was charged.
It is considered that the thermodynamic behavior of TRU (transuranium element) can be replaced by lanthanide-based elements,
U element was excluded.

Next, while cooling water is supplied to the melting crucible 1, the ingot crucible 20, and the upper induction coil 2 and the lower induction coil 3 of the melting crucible, the melting crucible 1 and the ingot crucible 2
r atmosphere.

(Example 1) Melting crucible 1 and ingot crucible 2
0 uses the following, and the upper induction coil 2 of the melting crucible
And the lower induction coil 3 was supplied with a high-frequency current having a maximum output of 20 kW and a frequency of 1 MHz.

(Melting crucible) (Ingot crucible) Material: Copper Material: Copper Internal structure: Water-cooled Internal structure: Non-water-cooled or water-cooled Upper opening inner diameter: 100 mm Upper inner diameter: 100 mm Lower opening inner diameter: 15 mm Lower inner diameter: 70 mm height of reduced cross section: 150 mm slit width: 0.2 mm height of fixed cross section: 20 mm Number of slits: 20 Slit width: 0.2 mm Number of slits: 28 Further, the upper induction coil 2 of the melting crucible 1, The following were used for the lower induction coil 3 and the induction coil 25 of the ingot crucible 20.

(Upper induction coil of melting crucible) (Lower induction coil of melting crucible) Material: Copper Material: Copper Inner diameter: 160 mm Inner diameter: 150 mm Outer diameter: 180 mm Outer diameter: 170 mm Cross section: 7 × 5 mm ² Cross section: 7 × 5 mm ² wall thickness: 1 mm Wall thickness: 1 mm (Induction coil of ingot crucible) Material: Copper Inner diameter: 55 mm Outer diameter: 75 mm Cross section: 7 × 5 mm ² wall thickness: 1 mm Subsequently, melting Outer diameter 1 from melt discharge nozzle 8 below crucible
A high-temperature finger 14a made of a graphite material having a length of 4 mm and a length of 100 mm was charged, and the melt discharge nozzle 8 was closed. High frequency current of 400K is applied to the upper induction coil 2 of the melting crucible.
When HZ was supplied and the temperature of the high-temperature finger reached 1800 ° C., an oxide and a reducing agent were charged under a condition satisfying the chemical equivalent until the layer thickness of the material at the lower portion of the melting crucible became 2 mm.

Thereafter, when the current supply to the upper induction coil 2 of the melting crucible 1 was stopped, the cooling of the high-temperature finger 14a and the material was promoted by the water-cooled melting crucible 1, and the melt began to solidify at the lower part of the crucible. . After the stable solidified body 23 is formed and the nozzle is closed, the high-temperature finger 1
After pulling out 4a from the melt discharge nozzle 8 of the melting crucible 1,
Instead, a low-temperature finger 14b made of a copper material which was previously cooled with water was inserted.

The following high and low temperature fingers were used. (High-temperature finger) (Low-temperature finger) Material: Graphite Material: Copper Outer diameter: 14 mm Outer diameter: 14 mm Length: 100 mm Length: 100 mm Subsequently, while supplying high-frequency current to the upper induction coil 2 of the melting crucible 1, After charging all the remaining materials into the melting crucible 1, an ignition rod (not shown) made of graphite material is inserted into the melting crucible 1 from above, and the tip thereof is located 5 mm above the surface layer on the central axis of the melting raw material. Stopped in position. The igniter rod was induction-heated, and the surface layer of the raw material for melting started to melt by the radiant heat. The dissolved material has an electric conductivity 1 /
As it increased to about 100, induced dissolution of the material began at the surface. Thereafter, the ignition rod was pulled upward.

As the dissolution of the material progresses, C in the oxide
r, Fe, Ni, Se, Mo, Tc, Ru, Rh, P
Each element of d, Ag, Cd, In, Sn, Sb, and Te is reduced by silicon nitride, and the molten phase of the mixed metal 1
It became 1 and gathered in the center of the melting crucible 1. This molten phase 11
Is further induction heated more remarkably than oxide,
Temperature. The temperature of the molten phase 12 of the oxide existing around the molten phase 11 of the metal alloy is increased by the heat transfer from the alloy and the induction heating from the upper induction coil 2 of the melting crucible 1 to cool the melting crucible 1. It dissolved completely, leaving about 1 mm of undissolved phase between the wall.

The output of the upper induction coil 2 of the melting crucible 1 was reduced to 1/2 of the maximum output in order to make the skull layer 13 including the undissolved layer a more stable solid skull layer. as a result,
The thickness of the skull layer 14 grew from 1 mm to 5 mm.
Then, remove the low-temperature finger 14b and remove the high-temperature finger 1
After replacement with 4a, a high-frequency current was supplied to the lower induction coil 3 of the melting crucible 1. High temperature finger 14a is 1800
When the temperature reached ° C., the high-temperature finger was quickly pulled out, and the melt (molten phase of metal and oxide) was discharged from the melt discharge nozzle 8 below the melting crucible 1 into the ingot crucible 20. At this time, the contact time between the high-temperature finger 14a and the melt is 3
Because of the short time of 0 second or less, little wear of the high-temperature finger occurred.

After the melt flowed into the ingot crucible 20, the melt was gradually cooled. After the completion of the cooling, the ingot crucible 20 was inverted, and the crucible was impacted several times. As a result, the solid metal phase 22 was successfully taken out of the ingot crucible 20. The solid oxide phase 21 having a small specific gravity was present on the upper layer of the solid metal phase 22. Thus, the simulated nuclear fuel could be processed.

At the stage where the above batch processing was repeated 100 times, there was a case where the solid oxide was attached to the cooled melt discharge nozzle 8 and the discharge was not performed smoothly. The ingot crucible 20 was worn by about 1%.

(Embodiment 2) The difference from the conditions of Embodiment 1 is that a sleeve is inserted into the nozzle portion of FIG.
A schematic cross-sectional view using a high-temperature finger is shown,
A sleeve made of a graphite material having an inner diameter of 10 mm, a thickness of 2 mm, and a length of 20 mm is provided on the melt discharge nozzle 8 and the outer diameter is 9 mm.
Hot and cold fingers reduced to mm were used in this sleeve 24. The batch processing was performed in the other conditions in the same manner as in Example 1. In this method, since the sleeve 24 was subjected to induction heating, the effect was observed 100 times at the stage where the effect was observed. When the state of the sleeve was observed, no oxide was attached. Thereafter, the sleeve was worn out at the stage when the processing was performed 200 times, and was replaced with a new sleeve.

(Example 3) The difference from Example 1 is that the ingot crucible 20 is a water-cooled structure made of a copper material having an insulating slit 9 similar to the melting crucible 1 and the induction coil 25 of the ingot crucible 20 is This is a structure that can supply a high-frequency current. . After discharging the melt into the ingot crucible 20, the output of the induction coil 25 of the ingot crucible 20 was reduced under the condition that the output became zero in 5 minutes, and the melt was gradually cooled. The batch processing was performed in the other conditions in the same manner as in Example 1. At that time, the induction coil of the ingot crucible was 400k at the maximum output of 30kW.
A high frequency current of a frequency of Hz was supplied. This processing is
Even if it repeats 0 times, the ingot crucible 20 does not wear at all,
It was found that it can be used for a long time.

(Comparative Example) Inner diameter 244 cm, rotation speed 40 r
The same simulated nuclear fuel as in Example 1 was melted in a PACT furnace with a pm refractory material. The dissolution amount was 1 ton, and it could be processed in 1 hour.

At this time, refractories lined up in the melting furnace were generated as secondary waste. Table 1 shows a comparison of secondary waste generation / treatment amount and oxide volume after melting / oxide volume before melting between Examples 1 to 3 of the present invention and a PACT furnace as a comparative example.

[0059]

[Table 1]

From Table 1, it is found that Examples 1 to 3 of the present invention
The amount of secondary waste generated / processed amount was reduced to 1/100 as compared with the PACT furnace of the comparative example. In addition, the ratio of oxide volume after melting / oxide volume before melting also decreased to 1/5. Therefore, the use of the method of the present invention greatly promotes the reduction of secondary waste and the reduction of oxide volume.

[0061]

According to the present invention, the contaminated oxide can be separated into a metal phase and an oxide phase, and the secondary waste can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of an apparatus showing an outline of an example of the present invention.

FIGS. 2A and 2B are partially enlarged schematic views of the insulating slit portion of FIG. 1, wherein FIG. 2A shows a state of a melting crucible, and FIG. 2B shows a state of an ingot crucible. .

FIG. 3 is a schematic cross-sectional view when a sleeve is inserted into the nozzle portion of FIG. 1 and a high-temperature finger is used therein.

FIG. 4 is a schematic longitudinal sectional view when an induction coil is used in the ingot crucible of FIG. 1;

[Explanation of symbols]

 1: melting crucible, 2: upper induction coil, 3: lower induction coil, 4: cooling water inlet, 5: cooling water outlet, 6: cooling water channel, 7: upper opening, 8: melt discharge nozzle, 9: melting Crucible insulating slit, 10: ingot crucible insulating slit, 11: molten phase of metal, 12: molten phase of oxide, 13: skull layer, 14a: high temperature finger, 14b: low temperature finger, 15a: first material supply device, 15b : Second material supply device, 16: deaeration port, 17: atmosphere chamber, 18: inert gas supply port, 19: high frequency power supply, 20: ingot crucible 21: solid oxide phase, 22: solid metal phase, 23 : Solidified body, 24: sleeve, 25: induction coil.

Claims (3)

[Claims] A chamber provided with a material supply means for supplying a molten material to an upper part thereof; a melting crucible provided with an induction coil on an outer periphery provided in an upper part of the chamber; It is a batch type melting and ingot making apparatus provided with an ingot crucible provided in the lower part of the inside of the chamber, and the lower part of the melting part of the upper part melting crucible has a smaller cross-sectional area toward the lower part, and is insulated from each other. It is composed of a plurality of segments that can be cooled.The melting crucible is provided with a melt discharge nozzle with a constant cross-sectional shape at the bottom of the melting crucible. A batch-type melting and agglomeration apparatus, characterized in that the size of the apparatus is reduced from the top to the bottom. 2. The batch type melting and ingot making apparatus according to claim 1, wherein the ingot making crucible has a cooling structure having a slit in a vertical direction, and an induction coil is provided on an outer periphery thereof. 3. A metal material containing an oxide and a reducing agent are charged into a melting crucible, heated and melted, and a melt obtained from the melting crucible is discharged into an ingot crucible. 3. A batch-wise melting and agglomeration method using the apparatus according to claim 1 or 2, wherein the solid is taken out.