JPH0441318B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a powder melting device that uses microwaves to melt and solidify powder, and more specifically, to a powder melting device that uses microwaves to melt and solidify powder. The present invention relates to a powder melting processing device that can process powdered materials.

The method for melting powder using microwaves is as follows:
Because heating is performed by dielectric loss based on the molecular motion of the substance that makes up the powder, the treated powder can be heated and melted from the inside evenly and efficiently, making it easier to heat and melt the powder than conventional electric heating or radiation heating. In principle, this method is much superior to that of the previous method. For this reason, it is used for various purposes in many industrial fields, but recently it has been applied to industrial waste treatment, where waste discharged from various industrial facilities and nuclear facilities is heated and melted by microwave irradiation. , a method of vitrifying and solidifying waste using silicon dioxide contained in waste is attracting attention.

Various types of melt processing equipment have been considered for this purpose. For example, as one such apparatus, a powder melting processing apparatus is known which includes a powder melting section consisting of a cylindrical container constituting a microwave cavity resonator.

The schematic structure of the powder melting section in this type of powder melting processing apparatus can be shown in FIG. That is, the powder melting section 1 transmits microwaves emitted from an oscillator 6 to the upper part of the cylindrical container 5, which is made up of metal cylinders 3 and 4 with high conductivity, which are joined or separated at the flange polymerization section 2. A microwave waveguide 7 that guides the inside, a matching mechanism 8 that performs matching during resonance, and a powder introduction pipe 10 that introduces the powder 9.
When microwaves are introduced, a microwave cavity resonator is formed which resonates in a mode that produces the strongest electric field inside the cylindrical container 5.

In this powder melting processing apparatus, the cylindrical container 5
After introducing a predetermined amount of the powder 9 into the powder 9, when microwave irradiation to the powder 9 is started, the powder 9 is heated and melted, and when it is left to cool, the particles contained in the powder 9 are melted. Depending on the components contained in the powder, such as silicon dioxide (if the powder 9 is waste from a nuclear facility), the powder 9 becomes vitrified or petrified and solidifies. This solidified powder 9 is separated from the metal cylinder 3 together with the cylinder 4, and is disposed of.

This device is considered to be the most excellent waste treatment device in terms of its ability to process a large amount of powder at one time. However, when trying to melt radioactive powder such as radioactive incineration ash obtained by incinerating waste at nuclear power plants, nuclear fuel processing plants, facilities that use radioisotopes, etc. using the above melting processing equipment, the following occurs. A big problem arises.

First, in the conventional powder melting processing apparatus, when the powder 9 is introduced into the cylindrical container 5 and then irradiated with microwaves, the cylindrical container 5 is heated by the by-product gas generated during the microwave irradiation. It becomes a pressure state and the powder 9
may be scattered or blown out from the flange portions 2 of the cylinders 3 and 4 or the connecting portions of the microwave introduction tube 7 and the powder introduction tube 10, contaminating the surrounding area. The fact that such powdery material 9 comes out is that the powdery material 9
If it is waste from a nuclear facility, it is extremely dangerous and poses a major safety problem.

Furthermore, in the case of radioactive powder (incineration ash), its particle size is small and it easily floats or scatters. Therefore, it is quite difficult to transport such dangerous radioactive powder from the incinerator to the melting processing equipment without scattering ash into the surrounding area.

The present invention has been made in view of these points, and its purpose is to eliminate the scattering and blowing out of the powder material outside the melting processing equipment during microwave irradiation of the powder material, and to further improve safety. An object of the present invention is to provide a powder melting processing apparatus.

The present invention achieves this object in a powder melting processing apparatus equipped with a powder melting section consisting of a cylindrical container constituting a microwave cavity resonator. A cylindrical-conical container is provided, the bottom of which communicates with the powder melting section, a powder introduction pipe is connected to the peripheral wall of the cylindrical body of the cylindrical-conical container in the connecting direction, and the cylindrical-conical container A powder collection section is formed by penetrating the top of the cylindrical body of the vessel with an exhaust pipe connected to an exhaust device at one end, and the powder collection section is brought into a negative pressure state to remove the powder. The powder is introduced from the powder storage section into the powder collection section as a swirling airflow, and is caused to settle along the peripheral wall of the container of the powder collection section and fall into the powder melting section. It is characterized by the following structure.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Figures 2 and 3 (A-A sectional view in Figure 2)
1 is an explanatory diagram showing an embodiment of the present invention, in which, like FIG. 1, 1 is a powder melting section, and a cylindrical container 5 in which cylinders 3 and 4 are removably connected at a flange overlapping section 2.
, a microwave waveguide 7 that introduces the microwave from the oscillator 6, and a matching mechanism 9. Reference numeral 11 denotes a powder collecting section, which includes a cylindrical-conical container 15 that communicates with the powder melting section 1 via a conduit 14, and one end of which is tangential to the peripheral wall of the cylindrical body 12 of the cylindrical-conical container 15. A powder introduction pipe 19 is connected to the powder material introduction pipe 19 whose other end is arranged in the powder storage section 18, and whose one end is installed passing through the top of the cylindrical body 12 of the cylindrical-conical container 15, and whose other end is arranged in the powder storage section 18. The exhaust pipe 23 is connected to an exhaust device 22 such as a turbo fan or a blade fan. The exhaust side of the powder collecting section 11, that is, the exhaust port of the exhaust device 22 is connected to the pipe line 2.
0 to the dust collector 24, and the dust collector 24
Thus, a small amount of powder accompanying the exhaust gas is completely collected and returned to the powder storage section 18 via the pipe 25.

Next, the operation of the powder melting processing apparatus having the above configuration will be explained.

In this processing apparatus, when the exhaust device 22 of the powder collection section 11 is started, the inside of the system consisting of the exhaust pipe 23, the cylindrical-conical container 15, the powder introduction pipe 19, etc. becomes a negative pressure state, and the powder The powder 9 in the powder storage section 18 is transferred to the cylindrical-conical container 1 through the powder introduction pipe 19.
5. Since one end of the powder introduction pipe 19 is tangentially connected to the peripheral wall of the cylindrical body 12, the powder 9 is sucked and introduced into the cylindrical body 12.
The powder flows through the cylindrical body 12 as a swirling air current, descends (settles) along the circumferential wall of the cylindrical body 12 under the action of centrifugal force, and passes through the funnel-shaped bottom 13 and the pipe 14 to become powder. The shaped body falls into the cylindrical container 5 of the melting section 1.
A predetermined amount of powder 9 is placed in the cylindrical container 5 of the powder melting section 1.
When microwaves are introduced from the microwave waveguide 7 and resonated together with the matching mechanism 8 while the exhaust device 22 is kept in operation in a state where the gas is deposited, a strong electric field is generated inside the cylindrical container 5. The powder 9 in the cylindrical container 5 is heated and melted by this electric field. At this time, dusting occurs due to disturbances such as generation of by-product gas, and even if some of the powder 9 returns to the powder collecting section 11, it will be captured by the swirling airflow and due to the action of centrifugal force. Cylindrical-conical container 15 again
The liquid sinks along the peripheral wall of the cylinder and falls into the cylindrical container 5. When the powder 9 in the cylindrical container 5 is irradiated with microwaves for a predetermined time and then left to cool, the powder 9 (molten material) in the cylindrical container 5 becomes glass-like or rock-like. and solidify. The solidified powder 9 is disposed of or stored together with the cylinder 4 that is separated from the cylinder 3.

It should be noted that the airflow exhausted through the exhaust pipe 23 of the powder collecting section 11 hardly contains any powder 9, but even if it does, it will be collected by the dust collector 24. The powder is collected, returned to the powder storage section 18, and subjected to the above-mentioned processing steps again.

FIG. 4 is an explanatory diagram of another embodiment of the present invention.
The same reference numerals are used for the same parts as those in the figures, and the explanation thereof will be omitted. The feature of this embodiment is that the powder collecting section 11
A valve 26 is provided in the pipe line 14 that communicates the powder melting section 1 with the
The point is that it has been established. The valve 26 is closed while the powder 9 in the cylindrical container 5 is being irradiated with microwaves. Therefore, even if the powder 9 is dusted by by-product gas during microwave irradiation, the powder does not return to the powder collecting section 11.

5 and 6 (BB sectional view of FIG. 5) are explanatory diagrams of still another embodiment of the present invention, and the same parts as in FIG. . The feature of this embodiment is that the cylindrical-conical container 15 constituting the powder collecting section 11 and the cylindrical container 5 constituting the powder melting section 1 are integrated, and a conduit (pipe line) connecting each container This is because the pipe line 14) in Figure 2 has been omitted. According to such a configuration, since the powder melting section 1 and the powder collecting section 11 are integrated, it is possible to realize a compact powder melting processing apparatus.

In each of the above embodiments, a turbo fan, a blade fan, etc. are used as the exhaust device 22 (these are omitted in FIGS. 4 and 5), but the present invention is not limited to this. Instead, it may be a fan such as a multi-blade fan or a propeller fan, a blower such as a turbo blower or a roots blower, or an ejector such as a water ejector or a steam ejector. Furthermore, the present invention does not require that the exhaust pipe 23 be provided with a dust collector 24 at the exhaust destination, and even if the exhaust destination of the exhaust pipe 23 is in the atmosphere or in an incinerator that incinerates waste. good. Furthermore, the present invention provides a powder collecting section 1.
Although the material of the cylindrical-conical container 15 constituting the container 1 is not limited, it is generally made of metal. In addition, in order to discharge the powder 9 after the melting process,
A discharge valve may be provided at the bottom of the cylindrical container 5.

As described above in detail, the powder melting processing apparatus of the present invention has a cylindrical body and a funnel-shaped bottom, and the funnel-shaped bottom has a powder collecting section that communicates with the powder melting section. The structure is such that the powder is brought into a negative pressure state as a swirling airflow and sucked into the cylindrical body, where it settles and is collected along the peripheral wall of the cylindrical body and falls into the powder melting section. . For this reason, it is not only possible to transfer the powder from the storage section without scattering the powder to the outside, but also by-product gas is generated during the microwave irradiation of the powder, and part of the powder is removed by dusting. Even if the powder returns to the powder collecting section, it is captured by the swirling airflow and returns to the powder melting section, and is not scattered to the outside. Therefore, it can be said to be extremely safe without contaminating the surrounding area.

[Brief explanation of drawings]

FIG. 1 is a conceptual explanatory diagram of a known powder melting processing apparatus, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a sectional view taken along line A-A in FIG. 2, and FIG. FIG. 5 is a diagram showing still another embodiment of the invention, and FIG. 6 is a sectional view taken along line BB in FIG. 5. 1...Powder melting part, 2...Flange part, 3,
4... Cylinder, 5... Cylindrical container, 6... Oscillator, 7
...Microwave waveguide, 8...Matching mechanism,
9... Powder, 11... Powder collection section, 12...
Cylindrical body, 13...funnel-shaped bottom, 14...pipe line, 15...cylindrical-conical container, 18...powder storage section, 19...powder introduction pipe, 22...exhaust device, 23...exhaust pipe, 24...dust collector.

Claims (1)

[Claims] 1 In a powder melting processing apparatus equipped with a powder melting section consisting of a cylindrical container constituting a microwave cavity resonator, the powder melting section is composed of a cylindrical body and a funnel-shaped bottom, and the funnel-shaped bottom is used for melting the powder. A cylindrical-conical container is provided which communicates with the cylindrical-conical container, and a powder introduction tube is tangentially connected to the peripheral wall of the cylindrical body of the cylindrical-conical container, and the top of the cylindrical trunk of the cylindrical-conical container is To,
A powder collection section is formed by penetrating an exhaust pipe whose one end is connected to an exhaust device, and the powder collection section is brought into a negative pressure state to remove the powder from the powder storage section. Powder material is introduced into a powder collecting section as a swirling airflow, settling along a peripheral wall of a container of the powder collecting section, and falling into the powder melting section. Melting processing equipment.