JP3391652B2 - Equipment for processing zinc-containing dust - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the treatment of zinc-containing dust.
The present invention relates to processing equipment , particularly processing equipment for separating and recovering zinc from zinc-containing dust such as steelmaking dust.

[0002]

2. Description of the Related Art In recent years, research has been conducted to recover various metals from industrial waste from the viewpoint of recycling resources, and wastes containing zinc in the form of oxides, for example, zinc-containing dust such as steelmaking dust Have been proposed. For example, in Japanese Unexamined Patent Publication No. 8-134557, zinc oxide is reduced by mixing steelmaking dust with a reducing agent such as carbon powder, filling the mixture in a processing container of a vacuum reduction furnace, and heating it under vacuum. A vacuum reduction method is disclosed in which the vaporized zinc is evaporated and the vaporized zinc is cooled with air to be recovered as zinc oxide.

[0003]

However, in the above-mentioned vacuum reduction method, since a mixture of steelmaking dust and a reducing agent is heated in a filling state in a processing container, not only zinc but also lead and other non-ferrous metals in steelmaking dust are heated. At the same time, the metal is also reduced and evaporated, and non-ferrous metals such as lead are mixed in the recovered zinc, and since the steelmaking dust that is powder is in a filled state, there is a problem that the heating efficiency is poor and the recovery rate decreases. Moreover,
Since the recovered zinc is in the form of oxide, its melting point is 1
There is also a problem that a very large amount of heat is required to regenerate it as metallic zinc, which is extremely high at about 975 ° C. Therefore, the present invention has a technical object to enable zinc in steelmaking dust to be directly recovered as high-purity metallic zinc and to perform it with high efficiency.

[0004]

Means for Solving the Problems As a means for solving the problems, the present invention provides a dust obtained by heating a zinc-containing dust simple substance under reduced pressure to obtain dust mainly containing iron oxide and zinc oxide. Is mixed with a reducing agent, heated under reduced pressure to reduce and evaporate zinc, and the generated vapor zinc is cooled under vacuum to form metallic zinc.

That is, the present invention relates to a treatment apparatus for zinc-containing dust.
The equipment is composed of a multi-stage furnace equipped with a stirring arm, a vacuum exhaust device is connected to each stage of the multi-stage furnace, a zinc-containing dust supply device is provided in the uppermost stage, and a reducing agent supply device is provided in the lower stage, and The zinc recovery device is provided in the middle of the lower vacuum exhaust pipe.

In the treatment facility of the present invention, first, when zinc-containing dust alone is heated under reduced pressure, non-metal components such as oil and chlorine and low-melting non-ferrous metals other than zinc such as lead evaporate from the zinc-containing dust. Therefore, these are removed to obtain dust mainly composed of iron oxide and zinc oxide, and when this is mixed with a reducing agent and heated under reduced pressure, zinc oxide is reduced and evaporated, so cool it under vacuum. It can be recovered as metallic zinc by solidifying it. Below, in the present invention
The present invention will be described in detail with reference to the accompanying drawings showing an example of such processing equipment .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The zinc-containing dust treatment facility according to the present invention shown in FIG. 1 is basically a multi-stage vacuum reduction furnace 1
And each processing chamber 2A, 2 connected to each stage of the vacuum reduction furnace 1
Vacuum evacuation devices 9A, 9 for evacuating the inside of B, 2C, 2D
B, 9C, 9D, a zinc-containing dust supply device 10 for supplying zinc-containing dust to the uppermost processing chamber 2A of the vacuum reducing furnace 1, and a reducing agent for the lower processing chamber 2C of the vacuum reducing furnace 1. Reducing agent supply device 20, processing chambers 2C and 2D for reducing and evaporating zinc, and the respective vacuum exhaust devices 9A and 9A
A metal recovery device 33A disposed in the exhaust pipe system B, 9C, 9D for recovering metal from the exhaust gas flowing in the exhaust pipe,
33B, 33C, 33D.

The vacuum reduction furnace 1 penetrates through the furnace body 2 and the furnace floors 3A, 3B, 3C and 3D that divide the interior of the furnace body 2 into a plurality of processing chambers 2A, 2B, 2C and 2D. A drive shaft 4 rotatably arranged coaxially with the central axis, and processing chambers 2A, 2B radially attached to the drive shaft 4 and
2C and 2D, and a plurality of stirring arms 5 that move to the central portion or the peripheral portion side of the furnace body 2 while agitating the dust in the furnace body 2. Heating means (eg radiant tube burner)
6 are provided. Further, a small amount of an inert gas such as N ₂ is supplied from the vicinity of the support portions of both ends of the drive shaft 4 to prevent the metal vapor from adhering and solidifying to the drive portion of the drive shaft 4. Dust filters 7A, 7B, 7C, 7D and a vacuum valve 8 are provided in each of the processing chambers 2A, 2B, 2C, 2D.
A vacuum exhaust device 9A, 9 through A, 8B, 8C, 8D
B, 9C and 9D are connected. The drive shaft 4 is driven by a drive motor 53 via a speed reducer 52 arranged at the lower end side.
Are linked to. The temperature of the steelmaking dust in each processing chamber of the vacuum reduction furnace 1 is controlled by providing thermocouples (not shown) at the dust supply position, the hearth center position, and the discharge position, and detecting the temperature by each thermocouple. The rotation speed of the stirring arm 5 is controlled based on the above.

The zinc-containing dust is supplied from the side wall of the furnace main body 2 to the uppermost processing chamber 2A by a zinc-containing dust supply device 10 described later, and is agitated by a stirring arm 5 while the central part of the uppermost furnace floor 3A. To the center of the next-stage hearth 3B through the communication passage 2a between the through-hole provided in the center and the drive shaft, and from there, the furnace is stirred by the stirring arm 5 It moves toward the peripheral portion of the floor 3B, is supplied to the front portion 27a of the reducing agent supply feeder 27 through the communication passage 2b provided in the peripheral portion of the hearth 3B, and after being mixed with the reducing agent there, It is supplied to the stage hearth 3C.
Thereafter, similarly, the furnace moves from the peripheral portion of the hearth 3C to the central portion and then from the central portion of the next-stage hearth 3D to the peripheral portion while being agitated, and the discharge provided at the peripheral portion of the lowermost hearth 3D is performed. Exit 2
After d, it is discharged outside the furnace as a residue. This outlet 2d
Is provided with a hopper including storage chambers 50a and 50b,
The vacuum sluice valves 51a, 51b and 51c can be shut off respectively. When discharging, first, the vacuum sluice valve 51b is closed and the vacuum sluice valve 51a is opened to supply a predetermined amount of residue to the upper storage chamber 50a through the discharge port 2d.
After closing 1a to shut off the upper accommodation chamber 50a from the outlet 2d, the vacuum sluice valve 51b is opened to supply the residue in the upper accommodation chamber 50a to the lower sac chamber 50b, and then the vacuum sluice valve 51b is closed. Upper accommodation chamber 50a and lower accommodation chamber 50b
After shutting off, the vacuum switching valve 51c is opened and the residue in the lower storage chamber 50b is discharged to the outside of the furnace. Although the illustrated furnace employs a four-stage vacuum reduction furnace, the present invention is not limited to this, and a vacuum reduction furnace having a two-stage, three-stage, or five-stage or higher hearth can be used. Needless to say.

The zinc-containing dust supplying device 10 is basically composed of a first hopper 11, a first screw feeder 12, a second hopper 13 and a second screw feeder 14, as shown in FIG. The second hopper 13 is composed of an upper storage chamber 13a, an intermediate storage chamber 13b and a lower storage chamber 13c, and the space between the upper storage chamber 13a and the intermediate storage chamber 13b and between the intermediate storage chamber 13b and the lower storage chamber 13b.
between the vacuum sluice valves 51a, 51b and 51c.
Vacuum sluice valves (not shown) similar to the above are respectively arranged, and the intermediate storage chamber 13b has a bag filter 15 and a vacuum valve 16 respectively.
Connected to the vacuum exhaust device 17 via the
c is connected to a vacuum exhaust device 19 via a vacuum valve 18.

The zinc-containing dust is thrown into the first hopper 11 of the zinc-containing dust supply device 10, conveyed by the first screw feeder 12 connected to the lower end of the first hopper 11, and then fed to the second hopper.
It is supplied to the upper storage chamber 13a of the hopper 13. The zinc-containing dust in the upper accommodation chamber 13a is
The vacuum switching valve between a and 13b is opened to open the intermediate storage chamber 13
b, the vacuum switching valve is closed, and both are shut off. Then, after vacuum-evacuating the intermediate storage chamber 13b and the lower storage chamber 13c by the vacuum exhaust devices 17 and 19, the vacuum switching valve between the intermediate storage chamber 13b and the lower storage chamber 13c is opened to contain zinc in the intermediate storage chamber 13b. Dust is in the lower chamber 1
3b. After that, the zinc-containing dust supplied to the upper storage chamber 13a is supplied to the lower storage chamber 13c below by a predetermined amount by opening and closing each vacuum sluice valve, and then from the second storage chamber 13c.
It is supplied from the side wall portion to the uppermost processing chamber 2A by the screw feeder 14.

The reducing agent supply device 20 basically has a first hopper 21 and a reducing agent transfer means 2 as shown in FIG.
2, a drying device 23, a crusher 24, a second hopper 25, a preheating device 26 and a reducing agent supply screw feeder 27, and the reducing agent transfer means 22 comprises a bucket conveyor 22A and a screw feeder 22B.
The reducing agent charged in the hopper 21 is transferred to the bucket conveyor 2
2A is lifted up and conveyed to the screw feeder 22B, and is supplied to the drying device 23 by the screw feeder 22B. The crusher 24 connected to the discharge end of the drying device 23 crushes the reducing agent hardened by drying and supplies it to the second hopper 25. The second hopper 25 includes an upper storage chamber 25a, an intermediate storage chamber 25b, and a lower storage chamber 25c, and between the upper storage chamber 25a and the intermediate storage chamber 25b and between the intermediate storage chamber 25b and the lower storage chamber 25c. A vacuum gate valve (not shown) is arranged in each case. The intermediate storage chamber 25b of the second hopper 25 is evacuated to the vacuum exhaust device 3 via the bag filter 28 and the vacuum valve 29.
0, and the lower storage chamber 25c is connected to a vacuum exhaust device 32 via a vacuum valve 31.

The metal recovery devices 33A, 33B, 33
C and 33D are vacuum exhaust devices 9A, 9B, 9C and 9D.
As shown in FIG. 4, the exhaust system is provided with a water-cooled rotary roller 34 and a scraper 35 for scraping metal adhered to the surface of the rotary roller 34, respectively. The collecting device hopper 38 for collecting is provided with a metal collecting device 33A via a vacuum gate valve 37,
It is connected to the discharge pipe 36 of 33B, 33C, 33D. The axis of the rotary roller 34 is arranged on the axis of the exhaust pipe of the vacuum exhaust device 9 so as to be orthogonal thereto, and the surface thereof is cooled by the cooling water W supplied therein. The cooling water W is supplied from one end side of the drive shaft S that rotationally drives the rotating roller 34, and is discharged from the other end side to the outside of the rotating roller. Each of the recovery device hoppers 38 has a vacuum exhaust device 41 through a dust remover 39 such as a filter and a vacuum valve 40.
It is connected to the. In addition, for simplification of the drawings, the exhaust system of each recovery device hopper 38 connected to the metal recovery devices 33B and 33C is the same as the exhaust system connected to the uppermost and lowermost metal recovery devices 33A and 33D. Since it has a configuration, the dust remover 39, the vacuum valve 40, and the vacuum exhaust device 41 are omitted.

A sub-system using the processing equipment according to the present invention having the above structure
The treatment of lead-containing dust can be carried out as follows . The case where steelmaking dust is treated as zinc-containing dust will be described as an example. First, in each of the processing chambers 2A, 2B, 2C, and 2D of the multistage vacuum reduction furnace 1, vacuum exhaust devices 9A, 9B, and 9C, Number Torr-10 by 9D
^The temperature is adjusted to ^-2 Torr, and by the heating means 6, the insides of the uppermost and second processing chambers 2A and 2B are set to about 900 ° C, and the third and fourth processing chambers 2C and 2D are set to about 950 ° C. Adjusted to.

In this state, the steelmaking dust is horizontally supplied from the side wall of the vacuum reduction furnace 1 to the uppermost processing chamber 2A by the screw feeder 14 of the zinc-containing dust supply device 10. The horizontal supply prevents dust from scattering in the furnace during supply. Uppermost processing chamber 2A
Steelmaking dust introduced into the furnace moves to the center of the hearth 3A while being stirred by the stirring arm 5, and 600
After being heated to ˜700 ° C., it is transferred to the second stage processing chamber 2B through the communication path 2a of the uppermost hearth 3A. During heating in the uppermost stage, oil, fluorine, chlorine and other non-metal components in the steelmaking dust are vaporized, and part of lead is vaporized and vaporized. Sent to the metal recovery unit 33A. Metal recovery unit 3
When the exhaust gas sucked into 3A hits the water-cooled rotary roller 34, the lead in the exhaust gas is cooled on the surface of the rotary roller 34 and solidifies and adheres and deposits on the surface. The lead is conveyed to the scraper side by the rotary roller. , Scraped by the scraper 35 and collected by the collecting device hopper 38. The exhaust gas is released to the atmosphere after removing fluorine, chlorine and the like by a known trap device (not shown).

The steel-making dust transferred to the second-stage processing chamber 2B moves on the hearth 3B from the central portion toward the peripheral portion while being stirred by the stirring arm 5, and is heated to about 900.degree. In this process as well, lead in the steelmaking dust is vaporized and vaporized, and is sent as exhaust gas from the processing chamber 2B to the metal recovery unit 33B by the action of the vacuum exhaust device 9B, and the uppermost processing chamber 2 is discharged.
Lead is recovered in the same manner as in case A, the exhaust gas is subjected to an appropriate exhaust gas treatment to remove non-metallic components, and then released to the atmosphere.

The steel-making dust reaching the peripheral portion of the second-stage hearth 3B is supplied to the front portion 27a of the reducing agent supply screw feeder 27 through a communication passage 2b provided at the bottom thereof. Since the communication passage 2b is filled with the steelmaking duct during operation, the gas generated in the processing chambers 2B and 2C does not enter the processing chambers 2B and 2C. Then, the steelmaking duct is mixed with the reducing agent during transportation and supplied to the processing chamber 2C of the third stage. The reducing agent is dehydrated by the drying device 23 and heated to about 420 ° C. by the preheating device 26. Next, the steelmaking dust moves from the peripheral portion toward the central portion on the hearth 3C while being stirred by the stirring arm 5, and is further heated to 900 to 950 ° C. At this time, the zinc oxide in the steelmaking dust is reduced and evaporated by the action of the reducing agent, and this zinc vapor is used as exhaust gas by the action of the vacuum evacuation device 9C and the processing chamber 2
It is sucked from C to the metal recovery unit 33C. Metal recovery unit 33
The exhaust gas sucked by C collides with the water-cooled rotary roller 34 and is cooled, and zinc vapor in the exhaust gas is solidified on the surface of the rotary roller 34 and adheres and deposits on the surface. The attached deposit (metal zinc) is scraped off by the scraper 35 while the rotating roller 34 makes one rotation, and is stored in the recovery device hopper.

On the other hand, the steelmaking dust moved to the central portion of the processing chamber 2C while being agitated is the communication passage 2c provided in the hearth 3C.
Through the processing chamber 2D of the fourth stage, and while being stirred by the stirring arm 5 there, it moves on the hearth 3D from the central portion toward the peripheral portion. The inside of this processing chamber 2D is 900-
Since the temperature is maintained within the range of 950 ° C., the remaining zinc in the steelmaking dust evaporates and is sent as exhaust gas from the processing chamber 2D to the metal recovery unit 33D by the action of the vacuum exhaust device 9D, and the third stage It is recovered as in the case of the processing chamber 33C.

[0019]

[Example] Fe, Mn, Cr, N as zinc-containing dust
i, Pb, Zn and Cl are included, the water content is 0.1% or less,
Steel scar with Zn content of 20%, Pb content of 3%, bulk density of 0.8 to 0.9 and grain size of 100 μ or less is used as a reducing agent for hot scarfer (FeO, water content: 7-1).
0%, bulk density: 2.5 to 3.0, particle size: 3 mm or less), and treated by the above apparatus. The recovered Zn had a purity of 93% or more, and the Zn content in the treated dust was 0.5% or less on average.

[0020]

As is apparent from the above description, according to the present invention, a simple substance containing zinc is heated under reduced pressure to remove non-ferrous metals and non-metallic components other than zinc, and the residual dust is mixed with a reducing agent. And heated under reduced pressure to reduce and evaporate zinc,
Since the generated steam zinc was cooled in a vacuum to solidify the zinc, most of lead and other non-ferrous metals and non-metallic components were removed before reduction, and thus the recovered metallic zinc contained no impurities. , High-purity zinc can be recovered. Also,
Since heating under reduced pressure is performed while stirring, highly efficient and uniform processing can be performed, and since the recovered metal is automatically recovered by the recovery device, it is not necessary to stop the vacuum reduction furnace for metal extraction, Excellent effects such as continuous operation can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a zinc-containing dust processing facility according to the present invention.

FIG. 2 is a configuration diagram of a zinc-containing dust supply device in the zinc-containing dust processing facility of FIG.

FIG. 3 is a configuration diagram of a reducing agent supply device in the zinc-containing dust treatment facility of FIG. 1.

FIG. 4 is a configuration diagram of a metal recovery device in the zinc-containing dust treatment facility of FIG. 1.

[Explanation of symbols]

1: Multi-stage vacuum reduction furnace 2: Main body of furnace 2A, 2B, 2C, 2D: Processing room 3A, 3B, 3C, 3D: Hearth 4: Drive shaft 5: Stirring arm 6: Heating means (burner) 9A, 9B, 9C, 9D: Vacuum exhaust device 10: Zinc-containing dust supply device 20: Reductant supply device 33A, 33B, 33C, 33D: Metal recovery device

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Okada 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (72) Inventor Toshikatsu Hara 1 Wano-wari, Arao-cho, Tokai-shi, Aichi Aichi Steel Co., Ltd. (72) Inventor Hirohiko Sasamoto 1 Wanowari, Arao-cho, Tokai-shi, Aichi Aichi Steel Co., Ltd. (72) Inventor Kazuhiro Suzuki 3-33 Konosu-cho, Toyota-shi, Aichi Toyokin Co., Ltd. (72) Inventor Nakatani Good, 2-4-7 Kyomachibori, Nishi-ku, Osaka-shi, Osaka Prefecture Chugai Furnace Industry Co., Ltd. (72) Noriyuki Nomura, 2-4-7, Kyomachibori, Nishi-ku, Osaka-shi, Osaka Prefecture (56) Reference: JP-A-9-202927 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C22B 1/00 -61/00

Claims (2)

(57) [Claims] 1. A plurality of processing chambers are divided into a plurality of processing chambers in multiple stages.
Furnace body with several hearths and connected to each stage of the furnace body
A vacuum exhaust device for vacuum exhausting each processing chamber, and the furnace book
Supply of zinc-containing dust to the uppermost treatment chamber of the body
A material supply device and a stirrer for stirring the material to be processed in each of the processing chambers.
Supplying a reducing agent to the stirring means and the processing chamber on the lower side of the furnace body
Reducing agent supply device and vacuum exhaust device from each processing chamber
And a metal recovery device installed in each exhaust pipe system to
The stirring means is rotatably arranged to penetrate the furnace body.
Drive shaft and the processing target in each processing chamber attached to the drive shaft.
A stirring arm that moves the material in a predetermined direction while stirring it
And each of the hearths is moved by stirring by the stirring arm.
Communication passage for supplying the processed material to the lower processing chamber
Zinc-containing dust treatment equipment characterized by comprising
Be prepared. 2. The furnace body is provided on a side wall of each of the processing chambers.
Equipped with heating means for heating and maintaining
The temperature detector is arranged in the hearth according to claim 1.
Processing equipment.