JP3319056B2 - Evaporated zinc recovery device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention realizes highly efficient dezincification, which is a problem when reusing waste materials such as punched materials of automobile steel sheets as raw materials for casting engine bodies and the like, and The present invention relates to an apparatus for recovering zinc vapor, which can recover zinc as metallic zinc.

[0002]

2. Description of the Related Art In Japan, where mineral resources are scarce, recycling of scrap is an important issue, and various attempts have been made for scrap recycling of steel materials. Among them, the scrap of galvanized steel sheet that has been galvanized to ensure corrosion resistance has been used to some extent in blast furnaces, cupolas, electric steelmaking furnaces, etc., but the transfer of zinc or zinc oxide to dust, There is a known problem of erosion by zinc.

[0003] In recent years, a large increase in the number of automobiles produced has led to an increase in scrap such as punched residual materials of galvanized steel sheets in automakers. However, due to recent pollution regulations and other factors, zinc in product cast iron has been reduced. At present, when the disposal of cupola with little contamination has progressed, the proportion of in-house scrap, which is punched residue, can be used as a raw material for cast iron for engine bodies and the like. This is because, in the case of low-frequency melting furnaces used in place of cupola, more zinc remains in the hot metal than cupola pig, and this zinc hinders the spheroidization of graphite and the formation of a stable oxide film. This is for deteriorating the quality of cast iron.

[0004] On the other hand, if the above-mentioned punched material is not used as a cast iron raw material but is replaced with, for example, a mild steel raw material, the zinc remaining in the molten steel is sufficiently reduced due to the higher evaporation of zinc due to the higher melting temperature. Problems such as dust treatment and shortening of the life of refractories in steelmaking furnaces are caused. Therefore, a chemical treatment method as disclosed in JP-A-4-210434 and a physical method as disclosed in JP-A-4-346681 have been proposed for dezincing of scrap.

[0005]

However, in the case of the above-mentioned proposed method, there are points to be practically improved in terms of pollution control of waste liquid, equipment cost, dezincing efficiency, running cost, zinc recovery rate, and the like.

Although it is known that dezincing can be completely realized in a so-called vacuum melting furnace used for melting high alloy special steel and superalloys containing active elements, equipment costs, running costs, productivity and the like are known. However, it is not practical for the production of cast iron castings and the recycling of iron scrap, and the recovery of zinc is not practical without some means.

Accordingly, the present invention solves the technical and economic problems in the above-mentioned fields, and responds to the needs called ecology and eco-materials in recent years. It is based on knowledge and research on condensation of gaseous substances.
An object of the present invention is to provide an apparatus for recovering zinc vapor which can efficiently and safely recover zinc vapor using a vacuum melting apparatus having a relatively low equipment cost of up to several kPa.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a vacuum vessel main body constituting a vacuum vessel,
A circle in which a melting furnace is accommodated to constitute a vacuum melting apparatus, and zinc evaporated from the raw material in the melting furnace is vapor-deposited on a lower surface of a vacuum vessel lid detachably attached to the vacuum vessel main body and is captured. The plate is provided so as to be movable up and down and rotatable, and further provided on the inner peripheral surface portion of the container lid body with a collecting gutter configured to collect the molten zinc scattered by the rotation of the disk. And

In addition, instead of providing the collecting gutter on the inner peripheral surface of the container lid, a configuration in which the collecting gutter is continuously provided inside the outer peripheral edge of the disk may be adopted.

Further, it is preferable that an inert gas introduction pipe is connected to the vacuum vessel.

Further, when a collecting gutter is provided on the inner peripheral surface of the container lid, the diameter of the disk is set to 1.2 to the inner diameter of the melting furnace.
It is preferable that the diameter of the disk is 1.5 times the inner diameter of the melting furnace.
It is good to make it 2.0 times.

[0012]

[Function] In a state where the raw material is put in the melting furnace and the disk is positioned at the upper part, when the raw material is heated under vacuum decompression, zinc is evaporated from the raw material and deposited on the lower surface of the disk. Can be Then, when the disk is lowered and approached to the melting furnace and rotated, the deposited zinc on the lower surface of the disk is melted by the radiant heat of the hot metal in the melting furnace and scattered outward by the centrifugal force received from the disk. . The scattered zinc collides with the inner peripheral surface of the container lid, flows down, and is collected by the collecting gutter.

On the other hand, when the collecting gutter is provided inside the outer peripheral edge of the disk, the molten zinc is moved toward the outer peripheral portion of the disk by centrifugal force and received by the collecting gutter.

In addition, when an inert gas is introduced into the vacuum vessel when melting and collecting the deposited zinc, a part of the zinc can be prevented from being re-evaporated.

Further, the diameter of the disk when the collecting gutter is provided on the inner peripheral portion of the container lid is 1.2 to 1.
When the diameter of the disk is 1.5 to 2.0 times when the collecting trough is provided on the outer peripheral edge of the disk, the evaporating zinc is efficiently applied to the lower surface of the disk. It can be deposited.

[0016]

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

FIG. 1 shows an embodiment of the present invention, in which a vacuum vessel main body 1 having a required depth and having a flange portion 1a at an upper end.
And a vacuum vessel lid 2 of a required height having a flange 2a at the lower end and having a vacuum seal 3 between the flanges 1a, 2a which can be attached to and detached from the vacuum vessel body 1 at a boundary.
And a vacuum vessel 4 made of a non-magnetic material comprising: a vacuum induction melting furnace 5 such as a low-frequency induction melting furnace or a high-frequency induction melting furnace in which the applied voltage system is modified in the vacuum vessel body 1; Further, an exhaust duct 6 connected to a vacuum pump (not shown) is detachably connected to the upper end of the vacuum vessel lid 2 as an exhaust system in a required inclined arrangement, and a vacuum valve is provided in the exhaust duct 6 in the middle. Install 7
Simple vacuum melting device 8 with ultimate vacuum of 0.5 to several kPa
Is configured.

The vacuum vessel 4 has a shaft 11 at the center of the upper end of the vessel lid 2 which is vertically moved and rotated by a lifting drive 9 and a rotation drive 10 installed on the vessel lid 2. Are arranged so as to penetrate vertically through a vacuum seal and rotary bearing 16, and at the lower end of the shaft 11,
A central portion of a disk 12 having a diameter of 1.2 to 1.7 times the inner diameter of the induction melting furnace 5 is attached via a heat insulating material 13,
The zinc evaporated from the molten raw material or the hot metal of the induction melting furnace 5 is vapor-deposited on the lower surface of the disk 12 to be captured, and the zinc captured on the lower surface of the disk 12 is melted by the radiant heat of the hot metal. The droplets can be scattered to the outer periphery by the centrifugal force generated by the rotation of the disk 12.

A collecting gutter 14 is attached to the inner peripheral surface of the lower end of the container lid 2 of the vacuum container 4 so as to project inwardly in a conical shape, and is scattered by the rotation of the disk 12. And an inert gas introduction pipe 1 for introducing an inert gas into the vacuum vessel 4 during the vapor deposition zinc melting and scattering step.
5 are connected via the exhaust duct 6, and further, a raw material addition tower 17 is provided in the middle of the exhaust duct 6, and the raw material cut out from the raw material addition tower 17 flows along the inclination of the exhaust duct 6. By dropping it together, it can be additionally supplied into the induction melting furnace 5.

The rotation speed of the disk 12 is 200 to 500.
rpm is set. In addition, the height of the container lid 2 is
2 is set so that it can be kept at 300 to 350 ° C. or lower by the radiant heat of the hot metal when it is located at the top.

When recovering zinc from a raw material including scraps of galvanized steel sheet, the container lid 2 of the vacuum container 4 is detached from the container main body 1 and set in standby at a predetermined position in the vicinity. Raw materials are charged into the induction melting furnace 5. When the container lid 2 is put on standby, it is also separated from the exhaust duct 6. When the raw materials are charged, the removed container lid 2 is attached to the container body 1, and the inside of the vacuum container 4 is evacuated (depressurized) through the exhaust duct 6.
At this time, the disk 12 is positioned at the top.

When the inside of the vacuum vessel 4 reaches a predetermined degree of vacuum, energization of the induction melting furnace 5 is started. With the start of energization of the induction melting furnace 5, the raw material gradually starts to evaporate from the stage before it glows red, and the evaporated zinc is deposited on the lower surface of the upper disk 12. When the induction melting furnace 5 is heated and gas is released, the degree of vacuum in the vacuum vessel 4 is reduced with a limited pumping capacity. At this time, since the temperature of the raw material has increased, As the vapor pressure of zinc increases, the evaporation of zinc continues.

The raw material in the induction melting furnace 5 becomes hot metal by heating.
Dezincification proceeds sufficiently even at a vacuum of several kPa, so that zinc remains in the hot metal at a level of several tens of ppm. at this point,
The vacuum valve 7 of the exhaust duct 6 is closed, an inert gas is introduced into the vacuum vessel 4 through an inert gas introduction pipe 15, and the rotation of the shaft 11 is performed by driving the rotation drive device 10 and the elevation drive device 9. The disk 12 is lowered while rotating to a position heated to 420 to 500 ° C. by radiation from the hot metal. When the raw material becomes hot metal in the induction melting furnace 5, the level is lowered. Therefore, if necessary, the raw material is cut out from the raw material addition tower 17 and dropped along the inclination of the exhaust duct 6, whereby the induction melting furnace 5 is dropped. You may make it supply additionally inside.

When the disk 12 lowered as described above is heated to 420 to 500 ° C. by the radiant heat of the hot metal,
The zinc deposited on the lower surface of the disk 12 is melted, flows toward the outer periphery by centrifugal force due to the rotation of the disk 12, and further forms droplets (or scales). The particles are scattered toward the inner peripheral surface of the body 2, collide and then flow down to be collected in the collection gutter 14. When the disk 12 is rotated for a predetermined time to complete the zinc collecting operation, the container lid 2 is removed from the container main body 1, and the hot metal in the induction melting furnace 5 is subjected to component adjustment and the molten metal is discharged. On the other hand, the disk 12 is cooled and then cleaned, and the metallic zinc in the collecting gutter 14 is recovered using a vacuum cleaner or the like.

In the above description, since the diameter of the disk 12 is 1.2 to 1.7 times the inner diameter of the induction melting furnace 5, that is, 1.2 to 1.7 times the surface diameter of the molten metal, zinc can be efficiently vapor-deposited and the liquid can be smoothly evaporated. Can be scattered as drops. That is, when the diameter of the disk 12 is 1.2 times or less the surface diameter of the molten metal, the amount of zinc deposited is small, and when it is 1.7 times or more, the zinc adheres to the outer peripheral portion during rotation and is partially separated. May cause rotation balance to be lost. Further, in the above, when the deposited zinc is melted and scattered after the dezincification is completed, there is a possibility that a part of zinc may be re-evaporated due to an increase in vapor pressure. Since the gas is introduced to perform the operation, re-evaporation can be prevented. Further, in the above, it is conceivable to arrange the disk 12 close to the induction melting furnace 5 from the beginning with the intention of increasing the amount of captured zinc disk 12 by evaporation, but in this case, due to the influence of radiant heating, the reverse is assumed. There is a problem that the evaporated zinc does not condense. Therefore, in the present invention, the disc 12 is positioned at the uppermost part during most of the period during the dezincing step.

Next, FIG. 2 shows another embodiment of the present invention. In a vaporized zinc recovery apparatus having the same structure as that shown in FIG. 1, a collecting trough 14 for collecting molten zinc is used.
Instead of being provided on the inner peripheral surface of the container lid 2 of the vacuum container 4, a collecting gutter 14 is continuously provided on the outer peripheral edge of the disc 12 via a conical flow guiding wall 18. The collecting gutter 14 can be moved up and down and rotated integrally with the disk 12. The diameter of the disk 12 is set to 1.5 to 2.0 times the inner diameter of the induction melting furnace 5. In this embodiment, when the raw material cut out from the raw material addition tower 17 is additionally supplied into the induction melting furnace 5 along the inclination of the exhaust duct 6, the raw material supply path is cut off by the presence of the collection gutter 14. In order to prevent the disk 12 from moving, the height of the container lid 2 is made higher than that of the above-mentioned embodiment so that the disk 12 can be further moved upward.

In the case of the embodiment shown in FIG. 2, when zinc deposited on the lower surface of the disk 12 is melted, the zinc is caused to flow toward the outer peripheral side of the disk 12 by centrifugal force due to the rotation of the disk 12, and the flow guide wall 18 is formed. Therefore, zinc can be collected by the collecting trough 14 in the same manner as in the above embodiment. At this time, since the diameter of the disk 12 is set to 1.5 to 2.0 times the inner diameter of the induction melting furnace 5, the evaporated zinc can be efficiently vapor-deposited and the equipment is advantageous. That is, the disk 1
2 is not more than 1.5 times the melt surface diameter,
The deposition of zinc on the outside of 4 makes it difficult to collect as it is scattered, and it also causes troubles such as infiltration into refractories. Since the container lid 2 becomes unnecessarily large, the capacity of the exhaust system must be increased. Therefore,
By setting the diameter of the disk 12 to be in the range of 1.5 to 2.0 times the melt surface diameter, it is preferable that zinc does not adhere to the outside of the collection gutter 14 and the equipment does not increase in size.

It should be noted that the present invention is not limited to only the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0029]

As described above, according to the apparatus for recovering evaporated zinc of the present invention, the following various excellent effects are exhibited. (1) The equipment cost is low because a vacuum melting apparatus having an evacuation capacity close to vacuum melting can be used. (2) Since there is no need to provide a water cooling device on the disk on which zinc is deposited, there is no need to cause an explosion accident due to water leakage. (3) Since dezincing in the charged raw material is almost completed at the stage before the molten metal is formed, there is no possibility of causing an accident such as bumping of the molten metal. (4) The recovered zinc is rich in metals and is therefore a valuable resource for reuse. (5) Since zinc does not penetrate into the refractory, the number of furnaces will not increase even if the usage ratio of galvanized steel scrap is increased. (6) It can be applied to existing low-frequency or high-frequency induction melting furnaces by modifying the applied voltage system to prevent discharge under reduced pressure. (7) Since the operations other than the dezincing process are the same as those for the melting and casting in air, good productivity can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of an apparatus for recovering evaporated zinc according to the present invention.

FIG. 2 is a schematic diagram of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container main body 2 Vacuum container lid 4 Vacuum container 5 Induction melting furnace (melting furnace) 8 Vacuum melting device 9 Elevation drive device 10 Rotation drive device 11 Shaft 12 Disk 14 Collection gutter 15 Inert gas introduction pipe

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C22B 19/30

Claims (5)

(57) [Claims] 1. A vacuum vessel main body constituting a vacuum vessel,
A circle in which a melting furnace is accommodated to constitute a vacuum melting apparatus, and zinc evaporated from the raw material in the melting furnace is vapor-deposited on a lower surface of a vacuum vessel lid detachably attached to the vacuum vessel main body and is captured. The plate is provided so as to be movable up and down and rotatable, and further provided on the inner peripheral surface portion of the container lid body with a collecting gutter configured to collect the molten zinc scattered by the rotation of the disk. An apparatus for recovering evaporated zinc, comprising: 2. The evaporative zinc recovery apparatus according to claim 1, wherein the collecting gutter is provided continuously inside the outer peripheral edge of the disk, instead of being provided on the inner peripheral surface of the container lid. 3. The apparatus according to claim 1, wherein an inert gas introduction pipe is connected to the vacuum vessel. 4. The method according to claim 1, wherein the diameter of the disk is from 1.2 to the inner diameter of the melting furnace.
2. The evaporative zinc recovery apparatus according to claim 1, wherein said apparatus is 1.7 times. 5. The diameter of the disk is 1.5 to 1.5 times the inner diameter of the melting furnace.
3. The apparatus for recovering evaporated zinc according to claim 2, wherein the ratio is 2.0 times.