JP3020888B2 - Molten metal distillation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal distillation apparatus for distilling and refining molten metal, and more particularly to a distillation apparatus for distilling and refining low and medium temperature molten metal having a high vapor pressure such as mercury and zinc. Related to the device.

[0002]

2. Description of the Related Art Conventionally, a metal refining method utilizing a metal evaporation phenomenon has been performed on low- and medium-temperature molten metals having a high vapor pressure, such as mercury (Hg) and zinc (Zn). Is generated, and this is condensed in a water-cooled retort and distilled under heating. In some cases, gas is injected into the metal under heating and depressurization (so-called bubbling) to increase the evaporation area to promote evaporation.

That is, the principle of distillation purification by a general heating and depressurizing method is as shown in FIGS. 4 and 5 attached to a vacuum pump side for increasing a vapor pressure by heating, lowering a boiling point by depressurizing, and depressurizing. The steam flow is guided, and a water-cooled condenser is installed in the steam flow path to aggregate the metal vapor.
Further, in order to promote evaporation, an inert gas is blown into the liquid metal to increase an evaporation area to increase efficiency.

[0003]

However, in the metal refining method according to the prior art described above, the liquid metal melted in the vessel only circulates by natural convection. The conduction of heat transmitted to the liquid metal through the container is not so good (better than water), so that there is a problem that the evaporation efficiency is poor and the purification ability cannot be improved. This is because the difference between the melting point and the boiling point of the metal is generally large. Particularly, in the case of a low-to-medium temperature molten metal subjected to distillation purification, the boiling point is often considerably higher than the melting point. In such a distillation purification method, there is only one evaporation surface of the molten liquid metal in the container, and only one surface of the liquid surface (surface) is used. At a temperature lower than the boiling point without increasing, the evaporation efficiency was deteriorated.

[0004] Further, it has been attempted to increase the surface of a gas layer to be evaporated by immersing a gas pipe in a container and performing gas bubbling from a lower portion of the container.
However, in such an attempt, the supply gas is increased in order to increase the gaseous layer surface area, and the liquid metal is cooled.
I will.

[0005] Therefore, an object of the present invention is to solve the above-mentioned problems in the prior art and to provide an improved molten metal distillation apparatus capable of improving the evaporation efficiency and the refining capacity thereof. I do.

[0006]

According to the present invention, in order to achieve the above object, a container for housing a metal therein, and a heating means for heating and melting the metal in the container to evaporate,
A molten metal distillation apparatus for cooling and condensing molten metal vapor evaporated in the container, thereby distilling the metal, wherein a gas pipe is immersed in the molten metal in the container, A molten metal distillation apparatus for injecting the heated inert gas into the molten metal while supplying an inert gas heated to a temperature higher than the temperature of the molten metal to perform gas bubbling is proposed.

Further, according to the present invention, in the above-described molten metal distillation apparatus, the inside of the vessel is provided with a chamber for performing gas bubbling with the inert gas.

According to the present invention, the above-mentioned molten metal distillation apparatus further comprises an electromagnetic stirring means for electromagnetically stirring the molten metal in the vessel.

That is, according to the present invention, based on the recognition that the molten liquid metal in the conventional general apparatus is in a natural convection state and is not sufficiently circulated, it is improved. To circulate this liquid metal, Thereby, the heat transfer supplied from the vessel was improved several times or more, and the evaporation was greatly promoted to improve the purification capacity.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, FIG. 1 shows a heater-equipped molten metal distillation apparatus according to one embodiment of the present invention.
In particular, it is an apparatus for distilling mercury (Hg).

In FIG. 1, reference numeral 10 designates a container for accommodating a low-to-medium temperature molten metal to be distilled therein, here a mercury. The container 10 is, for example, stainless steel (SUS) or Ceramic or the like is formed in a predetermined shape, specifically, as shown in the
1 is raised upward, and an annular concave portion 12 is formed around the raised portion. And the bottom of this container 10 and / or
Alternatively, for example, an electric heater 20 is provided around the periphery of the container, whereby the mercury inside the container 10 is heated and evaporated. Reference numeral 13 in the drawing is a mercury injection tube for injecting mercury into the container 10,
Reference numeral 14 denotes a mercury scattering particle prevention plate provided above the surface of mercury in the container 10, and reference numeral 50 denotes a heat insulating material provided so as to cover the periphery of the container 10.

The wall surface of the container 10 extends upward so as to cover the container, and the tip of the container 10 is formed into a tubular conduit and curved laterally. Is provided with a pipe 30 for passing a coolant (cooling water) such as water. That is, a condenser is formed by the refrigerant pipe 30, and a tank (distilled metal storage tank) 40 for storing distilled mercury obtained by condensation is attached below the condenser. Reference numeral 31 in the figure denotes a bundle of thin tubes provided in a tube downstream of the condenser. On the other hand, as shown in the drawing, a pipe 45 is also attached to a part of the side wall of the tank 40, and the pipe 45 is led to a vacuum pump (not shown) through a filter 46. That is, the evacuation and decompression of the tank 40 are performed by the vacuum pump.

According to the present invention, the annular recess 12 of the container 10 is immersed in mercury (Hg), and an inert gas such as argon (Ar) is supplied into the interior. A gas pipe 15 is led from the outside of the container 10 and is led to a header portion (gas foaming portion) 16 arranged along the annular concave portion. The outer wall of the header 16 has a number of pipe holes. Further, a gas heater 60 for heating and supplying the inert gas such as argon to the gas pipe 15 is provided outside the container 10. In addition, an induction coil 70 for generating a rotating magnetic field by applying an alternating current, for example, is arranged around the container 10.

Next, the operation of the apparatus for distilling a molten metal for mercury (Hg) according to the present invention whose structure has been described above will be described with reference to FIG. First,
Mercury (Hg) is put in the container 10, and then the electric heater 20 is energized to heat the container 10. Thereby, the mercury reaches the boiling point in the container 10 and evaporates. At this time, droplets of mercury splashed by the vaporized gas are stopped here by the mercury scattering particle prevention plate 14 provided above the mercury surface.

As described above, the mercury vapor evaporated in the vessel 10 is drawn through the pipe 45 by the vacuum pump, passes through a conduit extending above the vessel 10, and surrounds the refrigerant pipe 30. Led to a condenser with
There, it is cooled and condensed to obtain distilled mercury. Then, the obtained distilled mercury is stored in the tank 40.

According to the present invention, the inert gas heated to a high temperature by the gas heater 60 is supplied to the gas pipe 15 provided in the annular concave portion 12 of the container 10. This inert gas is spouted into the mercury in the container 10, so-called gas bubbling is performed to increase the surface of the gas layer to be evaporated, and furthermore, the liquid metal is circulated and supplied from the container. Greatly improve heat transfer. At this time, since the inert gas ejected into the mercury is heated to a high temperature by the gas heater 60, it does not cool the liquid metal, but rather promotes the evaporation while heating, thereby improving the purification capacity. Will be done.

Further, at this time, mercury as a liquid metal in the container 10 is agitated by applying an alternating current or the like to the induction coil 70 provided around the container 10 to generate a rotating magnetic field. Thereby, mercury is sufficiently circulated in the container 10, and thus, it is possible to promote the evaporation and further improve the refining capacity.

Next, FIG. 2 shows a molten metal distillation apparatus of the inside / outside type of the heater. In addition, in this heater internal / exterior type molten metal distillation apparatus, in addition to the electric heater 20 provided on the outer periphery of the container 10, a heating means such as an electric heater 25 is further provided in the container, At the bottom, it is immersed in a molten metal and arranged. In the molten metal distillation apparatus of the inside / outside type of the heater, the header portion (gas foaming portion) 16 for performing the bubbling with the inert gas is used to avoid deterioration of the heat transfer characteristic from the heater due to the bubbling. , Except that it is located above the electric heater 25 inside the container.

Also in this heater-internal / exterior type molten metal distillation apparatus, the mercury vapor evaporated in the vessel 10 is guided to the condenser provided with the refrigerant pipe 30 to be condensed. Obtained at this time, the inert gas ejected into the mercury is heated to a high temperature by the gas heater 60, without cooling the liquid metal,
Rather, it promotes evaporation while heating to improve the purification ability.

FIG. 3 shows a molten metal distillation apparatus according to another embodiment of the present invention. In addition, in this distillation apparatus, as is clear from the figure, the bottom of the container 10 is not provided with the annular concave portion as described above, but is flat. An exterior electric heater 20 and an immersion electric heater 25 are disposed outside and inside the bottom of the container 10, respectively.

In the other embodiment, a structure for performing a so-called gas lift function is provided inside the container 10. That is, a flow path partition plate 17 having a substantially “L” cross section is provided inside the container 10,
Thus, the inside is partitioned and divided into left and right sides in the figure. The header portion (gas foaming portion) 16 is disposed near the bottom surface on the left side of the container 10 in the figure. Here, an inert gas is injected into the liquid metal in the container 10 to perform bubbling.

According to this configuration, the inert gas injected into the liquid metal is supplied to the flow path partition plate 17 in the container 10.
As a result, the inside of one of the chambers (the left chamber in FIG. 3) partitioned upward is raised upward. For this reason, a driving force that pushes the liquid metal in the room upwards due to the rise of the inert gas is generated. Due to the driving force for pushing the liquid metal upward, a flow of the liquid metal as shown by an arrow in the drawing is generated, and the liquid metal inside the container 10 is further actively circulated. This greatly improves the heat transfer from the heating means at the bottom of the vessel 10 and greatly enhances the evaporation to improve the purification capacity.

As described above, in the other embodiment, it is possible to obtain a means for stirring the liquid metal in the container at low cost without using a relatively expensive member such as the induction coil 70 described above. become. At this time, similarly to the above embodiment, the gas layer surface to be evaporated is increased by gas bubbling of the inert gas, and the inert gas is heated at a high temperature by the gas heater 60. Therefore, the evaporation of the molten metal in the container is promoted while heating, rather than cooling the liquid metal, and the refining ability is improved.

In the embodiment shown in FIGS. 1 to 3, the inert gas ejected into the liquid metal inside the container 10 is heated at a high temperature by the gas heater 60. Is preferably set higher than the temperature of the liquid metal in the container. In other words, the higher the supply gas temperature is than the temperature of the liquid metal in the container, the more heat can be supplied to the liquid metal and the amount of steam that dissolves into the high-temperature gas bubbles increases, and the amount of generated steam increases and evaporates. Efficiency is improved. Also, the pressure of this inert gas is
It is preferable that the pressure be the minimum pressure that overcomes the hydraulic pressure loss of the gas blown between the container internal pressure and the liquid metal head (that is, the minimum pressure that overcomes the liquid pressure of the liquid metal).

A pipe 4 is provided on the side wall of the storage tank 40.
The displacement of a vacuum pump provided through the
The header (gas bubble) 1
Naturally, it must be larger than the sum of the blowing gas amounts from 6. Further, in the above-described embodiment, only mercury (Hg) was described as the metal to be purified by distillation. However, the present invention is not limited to this, and further, the vapor pressure of zinc (Zn) or the like may be reduced. It goes without saying that the present invention can be applied to high low and medium temperature molten metals. Also, as for the heating means, in the above embodiment, only the electric heater has been described. In particular, the exterior heating means is not limited to the above electric heater, and may be a heater using a flame, An induction furnace using high-frequency electromagnetic induction heating may be used.

[0026]

As is clear from the above detailed description, according to the molten metal distillation apparatus of the present invention, it is possible to greatly improve the evaporation efficiency and improve the refining capacity, and Means for this purpose are relatively simple, and exhibit an excellent effect that it can be realized at low cost .

[Brief description of the drawings]

FIG. 1 is an overall cross-sectional view illustrating a structure of a heater-equipped molten metal distillation apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a structure of a heater internal / exterior type molten metal distillation apparatus according to an embodiment of the present invention.

FIG. 3 is a sectional view illustrating a structure of a molten metal distillation apparatus according to another embodiment of the present invention.

FIG. 4 is a diagram for explaining the structure and principle of a conventional general distillation / purification apparatus using a heating and decompression method.

FIG. 5 is also a view for explaining the structure and principle of a conventional general distillation and purification apparatus using a heating and decompression method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Container 15 Gas pipe 16 Header part (gas foaming part) 20 Electric heater 30 Refrigerant pipe 40 Tank (distilled metal storage tank) 60 Gas heater 70 Induction coil

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) C22B 9/00-9/22 B01D 3/00

Claims (3)

(57) [Claims] A container for storing a metal therein; heating means for heating and melting the metal in the container to evaporate the molten metal; and cooling and condensing the vapor of the molten metal evaporated in the container to obtain a metal. Is a molten metal distillation apparatus for distilling a gas pipe in a molten metal in the container, further supplying an inert gas heated to a temperature higher than the molten metal temperature to the gas pipe. The molten metal distillation apparatus, wherein the heated inert gas is injected into the molten metal to perform gas bubbling. 2. The apparatus for distilling molten metal according to claim 1, wherein a chamber for performing gas bubbling with the inert gas is provided separately from the inside of the vessel. . 3. The molten metal distillation apparatus according to claim 1, further comprising electromagnetic stirring means for electromagnetically stirring the molten metal in the vessel.