JPH0734149A - Evaporated zinc recovery device - Google Patents

Abstract

(57) [Summary] [Purpose] To recover zinc from scrap efficiently with inexpensive equipment. [Structure] Vacuum container 4 including container body 1 and container lid 2
Then, the induction melting furnace 5 is housed therein, and a simple vacuum melting device 8 is configured. The disk 12 is arranged in the container lid 2 so as to be vertically movable and rotatable. A collection trough 14 is provided on the inner peripheral surface of the container lid 2. The scrap charged in the melting furnace 5 is heated, and the evaporated zinc is vapor-deposited on the lower surface of the disk 12 placed at the top. Then, the disk 12 is lowered, the vaporized zinc is melted by the heat of the hot metal, and the molten zinc is blown off by the rotation of the disk 12 and collected by the collecting trough 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention realizes a high efficiency of dezincification, which is a problem when reusing waste materials such as punching residual materials of automobile steel sheets as raw materials for casting engine bodies and the like, and The present invention relates to an evaporated zinc recovery device capable of recovering zinc as metallic zinc.

[0002]

2. Description of the Related Art In Japan, where mineral resources are scarce, recycling scrap is an important issue, and various attempts have been made to recycle scrap of steel materials. Among them, scraps of galvanized steel sheets galvanized to ensure corrosion resistance have been used to some extent in blast furnaces, cupolas, electric steelmaking furnaces, etc., but zinc or zinc oxide transfer to dust, furnace body fire resistance The problem of zinc erosion of materials is known.

By the way, the recent great increase in the number of automobiles produced has led to an increase in scraps such as punching residual materials of galvanized steel sheets in automobile manufacturers. However, due to recent pollution regulations and other factors, zinc in product cast iron is Nowadays, with the progress of abandonment of cupola, which contains a small amount of contaminants, the rate at which punching residual material, which is in-house scrap, can be used as a raw material for cast iron such as engine bodies is decreasing. This is because in the case of the low-frequency melting furnace used instead of cupola, the amount of zinc remaining in the hot metal is higher than that of cupola hot metal, and this zinc hinders the spheroidization of graphite and the formation of a stable oxide film. , To deteriorate the quality of cast iron.

[0004] On the other hand, if the above punching residual material is replaced with a cast iron raw material and is, for example, a mild steel raw material, a large amount of zinc evaporates due to the high melting temperature, so that the zinc remaining in the molten steel is sufficiently reduced. This causes problems such as dust treatment and shortening of the life of refractories of steelmaking furnaces. Therefore, for dezincing scrap, 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.

[0005]

However, in the case of the above-proposed method, there are some points to be practically improved in measures against pollution of waste liquid, equipment cost, dezincification efficiency, running cost, zinc recovery rate and the like.

Incidentally, it is known that dezincification can be completely realized in a so-called vacuum melting furnace used for melting high alloy special steel and superalloy containing active elements, but equipment costs, running costs, productivity, etc. Therefore, it cannot be said that it is practical for the production of cast iron castings and the recycling of iron scrap, and it is not practical for the recovery of zinc without some measures.

Therefore, the present invention solves the technical and economic problems in the above-mentioned fields, and in order to meet the needs called the ecology and ecomaterials of the recent years, the temperature and vacuum degree of evaporation of zinc, It was made based on the knowledge and research on the condensation of gas phase substances, and the ultimate vacuum degree was 0.5.
The present invention aims to provide an evaporated zinc recovery device that can recover evaporated zinc efficiently and safely by using a vacuum melting device with a relatively low equipment cost of up to several kPa.

[0008]

In order to solve the above-mentioned problems, the present invention provides a vacuum container main body which constitutes a vacuum container,
A vacuum melting device is configured to accommodate the melting furnace, and a vacuum container lid that is attachable to and detachable from the vacuum container body is formed by depositing zinc evaporated from the raw material in the melting furnace on the lower surface and capturing it. A structure in which a plate is rotatably and rotatably provided, and further, a collecting gutter is provided on an inner peripheral surface portion of the container lid body so as to collect the molten zinc scattered by the rotation of the disk. And

Further, instead of providing the collecting trough on the inner peripheral surface of the container lid, the collecting trough may be connected to the inside of the outer peripheral edge of the disc.

Further, it is preferable that an inert gas introducing pipe is connected to the vacuum container.

Furthermore, in the case where a collecting trough is provided on the inner peripheral surface of the container lid, the diameter of the disk is 1.2 to the inner diameter of the melting furnace.
It is good to set 1.7 times, and when the collecting gutter is connected to the outer peripheral edge of the disk, make the diameter of the disk 1.5 times the inner diameter of the melting furnace.
It is better to set the value to 2.0 times.

[0012]

[Function] When the raw material is put in the melting furnace and the disc is positioned in the upper part, when the raw material is heated under reduced pressure in vacuum, zinc is evaporated from the raw material and deposited on the lower surface of the disc. To be Then, when the disk is lowered and brought closer to the melting furnace and rotated, the evaporated zinc on the lower surface of the disk is melted by the radiant heat of the hot metal in the melting furnace, and is scattered outward by the centrifugal force received from the disk. . The scattered zinc collides with the inner peripheral surface of the container lid, then flows down and is collected by a collecting trough.

On the other hand, when the collecting troughs are continuously provided inside the outer peripheral edge of the disc, the molten zinc is attracted to the outer peripheral portion of the disc by the centrifugal force and received by the collecting trough.

Further, when the vaporized zinc is melted and collected, if an inert gas is introduced into the vacuum container, it is possible to prevent part of the zinc from being re-evaporated.

Further, with respect to the inner diameter of the melting furnace, the diameter of the disk when the collecting trough is provided on the inner peripheral portion of the container lid is 1.2 to 1.
If the diameter of the disk when the collecting gutter is provided on the outer peripheral edge of the disk is set to be 1.5 to 2.0 times, the evaporated zinc can be efficiently applied to the lower surface of the disk. It becomes possible to be vapor-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 container body 1 having a flange 1a at the upper end and having a required depth.
And a vacuum container lid 2 of a required height, which has a flange portion 2a at its lower end and is attachable to and detachable from the vacuum container body 1 with a vacuum seal 3 between both flange portions 1a and 2a as a boundary.
An 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 is housed in the vacuum container body 1. Further, as an exhaust system, an exhaust duct 6 connected to a vacuum pump (not shown) is detachably connected to the upper end of the vacuum container cover 2 in a required inclined arrangement, and a vacuum valve is provided in the middle of the exhaust duct 6. 7 is installed,
Simple vacuum melting device 8 with ultimate vacuum of 0.5 to several kPa
Make up.

In the vacuum container 4, a shaft 11 is arranged at the center position of the upper end of the container lid 2 so as to be moved up and down and rotated by a lift drive device 9 and a rotation drive device 10 installed on the container cover 2. Is arranged so as to pass through in the vertical direction via the vacuum seal and rotary bearing 16, and at the lower end of the shaft 11,
The center portion of a disk 12 having a diameter 1.2 to 1.7 times the inner diameter of the induction melting furnace 5 is attached via a heat insulating material 13,
The molten raw material of the induction melting furnace 5 or zinc evaporated from the hot metal is vapor-deposited and captured on the lower surface of the disk 12, and the zinc captured on the lower surface of the disk 12 is melted by the radiant heat of the hot metal. The rotation of the disk 12 allows the droplets to be scattered to the outer periphery by centrifugal force.

Further, a collecting trough 14 which is formed so as to project inward in a conical shape is attached to the inner peripheral surface of the lower end of the container lid 2 of the vacuum container 4 and is scattered by the rotation of the disc 12. An inert gas introducing pipe 1 for allowing the zinc droplets to be received by the collecting trough 14 and for introducing an inert gas into the vacuum container 4 into the container lid 2 during the vapor deposition zinc melting and scattering process.
5 are connected via the exhaust duct 6, and a raw material addition tower 17 is connected in the middle of the exhaust duct 6, and the raw material cut out from the raw material addition tower 17 is guided along the slope of the exhaust duct 6. In addition, it is made to fall so that it can be additionally supplied into the induction melting furnace 5.

The rotation speed of the disk 12 is 200 to 500.
It is set to rpm. Further, the height of the container lid 2 is the disc 1
When 2 is located at the top, it is set so as to be kept at 300 to 350 ° C. or lower by the radiant heat of the hot metal.

When recovering zinc from a raw material containing scraps of galvanized steel sheet, the container lid 2 of the vacuum container 4 is removed from the container body 1 in advance and left at a predetermined position in the vicinity thereof. Raw materials are charged into the induction melting furnace 5. When the container lid 2 is on standby, it is also disconnected from the exhaust duct 6. When the raw materials are charged, the removed container lid body 2 is attached to the container body 1, and the inside of the vacuum container 4 is evacuated (decompressed) 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, the induction melting furnace 5 is turned on. When the induction melting furnace 5 is energized, the raw material gradually begins 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 container 4 decreases with a limited exhaust capacity, but at this time, since the temperature of the raw material rises, that is, Since the vapor pressure of zinc also increases, the evaporation of zinc continues.

The raw material in the induction melting furnace 5 becomes hot metal by heating, but it is 10 at 1300 to 1400 ° C., which is hot metal.
Since dezincification proceeds sufficiently even at a vacuum degree of several kPa, the amount of zinc remaining in the hot metal becomes 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 container 4 by the inert gas introduction pipe 15, and the rotation drive device 10 and the elevation drive device 9 are driven to operate the shaft 11. The disk 12 is rotated and lowered to a position where it is heated to 420 to 500 ° C. by the 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 to cause the induction melting furnace 5 to fall. You may make it additionally supply in.

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 will be melted, and this will flow toward the outer peripheral direction due to the centrifugal force due to the rotation of the disk 12, and will further become droplets (or scaly pieces) to form a container lid. The particles are scattered toward the inner peripheral surface of the body 2, collide with each other, and then flow down to be collected in the collecting trough 14. When the disk 12 is rotated for a predetermined period of time to complete the zinc collecting operation, the container lid 2 is removed from the container body 1, and the molten pig iron in the induction melting furnace 5 is adjusted in composition and tapped. On the other hand, the disk 12 is cleaned after cooling and the metallic zinc in the collecting trough 14 is recovered by using a vacuum cleaner or the like.

In the above, 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, the diameter of the surface of the molten metal, the evaporated zinc can be efficiently deposited and the liquid can be smoothly fed. Can be scattered as drops. That is, if the diameter of the disk 12 is 1.2 times or less of the molten metal surface diameter, the amount of zinc vapor deposition is small, and if it is 1.7 times or more, zinc adheres to the outer peripheral portion during rotation and is partially peeled. There is a possibility that the rotation balance may be lost due to the occurrence of the. Further, in the above, when vaporized zinc is melted and scattered after the completion of dezincification, the vapor pressure may increase and a part of zinc may be re-evaporated. Since gas is introduced to carry out the work, 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 in order to increase the capture amount of the evaporated zinc disk 12, but in that case, due to the effect of radiation heating, the reverse There is a problem that evaporated zinc does not condense. Therefore, in the present invention, the disc 12 is positioned at the top most of the time during the dezincification process.

Next, FIG. 2 shows another embodiment of the present invention. A collecting trough 14 for collecting molten zinc in a vaporized zinc recovery apparatus having the same structure as shown in FIG.
Instead of being provided on the inner peripheral surface of the container lid 2 of the vacuum container 4, a collecting trough 14 is continuously provided on the outer peripheral edge of the disk 12 via a conical guiding wall 18. The collecting trough 14 is configured so that it can be raised and lowered and rotated integrally with the disc 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 addition, 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 blocked by the existence of the collection trough 14. Therefore, the height of the container lid 2 is made higher than that of the above-mentioned embodiment so that the disk 12 can move further up.

In the case of the embodiment shown in FIG. 2, when the zinc deposited on the lower surface of the disk 12 melts, it is caused to flow to the outer peripheral side of the disk 12 by the centrifugal force due to the rotation of the disk 12, and the flow guide wall 18 is formed. Since it is made to flow down along with, zinc can be collected by the collecting trough 14 as in the case of the above-mentioned embodiment. At this time, since the diameter of the disk 12 is 1.5 to 2.0 times the inner diameter of the induction melting furnace 5, evaporated zinc can be deposited efficiently and it is also advantageous in terms of equipment. That is, disk 1
If the diameter of 2 is less than 1.5 times the diameter of the molten metal surface, the collection trough 1
If zinc is vapor-deposited on the outside of 4 and scattered, it will not only be difficult to recover, but it will also enter into refractories and cause troubles, and if it is 2.0 times or more. Since the container lid body 2 becomes unnecessarily large, the capacity of the exhaust system must be increased. Therefore,
By setting the diameter of the disk 12 within the range of 1.5 to 2.0 times the diameter of the molten metal surface, it is suitable without adhering zinc to the outside of the collecting trough 14 and without increasing the size of the equipment.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0029]

As described above, the evaporated zinc recovery apparatus of the present invention exhibits various excellent effects as described below. (1) Equipment costs are low because a vacuum melting device with an exhaust capacity close to that of vacuum melting can be used. (2) Since it is not necessary to provide a water cooling device on the disk on which zinc is deposited, it is not necessary to cause an explosion accident due to water leakage. (3) Since dezincification in the charging raw material is almost completed before it becomes a molten metal, there is no risk of accident such as molten metal bumping. (4) Since the recovered zinc is rich in metals, it is valuable as a reusable resource. (5) Since there is no intrusion of zinc into the refractory, the number of furnace constructions will not increase even if the proportion of galvanized steel scrap used is increased. (6) It can be applied to existing low-frequency and high-frequency induction atmosphere melting furnaces by modifying the applied voltage system so as to prevent discharge under reduced pressure. (7) Other than the dezincification process, the work is the same as the work of melting in air and casting, so good productivity can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of an evaporated zinc recovery device of 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 Elevating drive device 10 Rotation drive device 11 Shaft 12 Disc 14 Collection gutter 15 Inert gas introduction pipe

Claims (5)

[Claims] 1. A vacuum container body constituting a vacuum container,
A vacuum melting apparatus is configured to accommodate a melting furnace, and a vacuum container lid that is detachably attached to the vacuum container body is provided with a circle for depositing zinc evaporated from the raw material in the melting furnace on the lower surface to capture it. A structure in which a plate is rotatably and rotatably provided, and further, a collecting gutter is provided on an inner peripheral surface portion of the container lid body so as to collect the molten zinc scattered by the rotation of the disk. An apparatus for recovering evaporated zinc, comprising: 2. The evaporated zinc recovery apparatus according to claim 1, wherein the collection 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 evaporated zinc recovery apparatus according to claim 1, wherein an inert gas introducing pipe is connected to the vacuum container. 4. The diameter of the disk is 1.2 to the inner diameter of the melting furnace.
The evaporated zinc recovery apparatus according to claim 1, which is 1.7 times larger. 5. The diameter of the disk is 1.5 to the inner diameter of the melting furnace.
The evaporated zinc recovery apparatus according to claim 2, which is 2.0 times as large.