JPS6342130Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement in an apparatus for separating zinc oxide and metallic zinc in top dross floating on the surface of a molten zinc bath in a molten galvanizing line and recovering metallic zinc.

In recent years, continuous hot-dip galvanizing lines have been made faster by introducing gas throttling technology to control the amount of zinc deposited. However, in the gas squeezing method, the zinc adhering to the surface of the strip is oxidized by the gas ejected from the slit nozzle, which causes the zinc to become oxidized and become a highly viscous mud-like floating substance called top dross, which is deposited on the surface of the zinc bath. When the amount of top dross deposited increases, it adheres to the surface of the product and seriously impairs its appearance. Therefore, when a certain amount of top dross has accumulated, it is manually pumped out to clean the surface of the zinc bath.

On the other hand, this top dross contains a large amount of metallic zinc in addition to zinc oxide, and when it is pumped out, metallic zinc is also taken out, causing a loss of zinc. For this reason, it has been conventionally practiced to recover metallic zinc from top dross.

The general method for recovering metallic zinc from Topdross is to add an oxide separating agent (flux) to the molten Topdross and make the Topdross react with the flux to separate zinc oxide from metallic zinc. The following types of recovery devices are known.

In other words, the conventional equipment consists of a recovery machine body that stirs and mixes molten topdross and flux, an ash collection box that collects ash, which is a reaction product of topdross and flux, in water, and a harmful gas generated by the reaction between topdross and flux. It consists of a cleaning tower (wet type dust collector) to prevent dust and fine powder from flying into the air.

However, this type of recovery device has a complex overall structure, requires a lot of man-hours for maintenance and inspection, and since the reaction product, ash, is recovered wet, solid-liquid separation takes time and is inefficient. Moreover, since the transport method of the assembly is mechanical (screw conveyor), there are drawbacks such as frequent breakdowns.

This invention was an improvement to solve the above-mentioned drawbacks of the conventional method, and its main features are that the collection of the ashes is performed directly in a dry state instead of the conventional wet method; The method is such that the dust is removed using a dust removal device such as a dust catcher.

Hereinafter, one embodiment of this invention will be described based on the drawings.

This idea involves attaching a top dross reservoir 2 of an appropriate size to the end of a hot-dip galvanizing tank 1 so as to communicate with the galvanizing tank, and installing a vertical agitator in this top dross reservoir to stir and mix the top dross and flux. A container 3 is provided. This stirring vessel contains
A rotating shaft 4 having a stirring blade 5 at the bottom thereof is installed vertically through the upper lid 6 of the container, and is driven by a reversible motor 7 with a speed reducer. Moreover, inside this stirring container 3,
An annular compressed air injection nozzle 8 that sprays compressed air from above against the debris generated by the reaction between top loss and flux is attached to, for example, the upper lid 6, and the compressed air blown from this compressed air injection nozzle scatters the debris in the stirring vessel 3. I try to let them do it.

10 is a flux inlet, 11 is an ash outlet, and 12 is a gas outlet, and the ash outlet 11 is provided near the surface of the zinc bath. 13 is gas piping,
14 is a dust collection fan, 15 is an ash transport pipe, 16
17 is a dust catcher, 17 is a blower, and 18 is a wet type dust collector. The gas generated in the stirring container 3 is sucked by a dust collection fan 14, and the wet type dust collector 18 removes HCl and dust generated from the flux. On the other hand, the ash generated by the reaction between the top loss and the flux is sucked by the blower 17 and sent to the wet dust collector 18 via the dust catcher 16, where it is processed together with the gas and released into the atmosphere. It is becoming more and more common.

When separating and collecting top loss using the above device, first, the top loss 20 floating on the surface of the zinc bath in the hot-dip galvanizing tank 1 is pumped out, the top lid 6 of the stirring container 3 is opened and the top loss is poured into the container, and then the top lid is poured into the container. Close and pour flux 2 from flux inlet 10.
1 into the stirring container 3. The flux to be used may be, for example, one whose main component is ZnCl ₂ mixed with auxiliary agents such as NH ₄ Cl type and NaHCO ₃ type.

Next, the reversible motor 7 with a speed reducer is driven, and the top dross and flux are stirred and mixed by the stirring blade 5. At this time, zinc oxide and metallic zinc are separated by the reaction between the top dross and the flux, and the metallic zinc settles due to the difference in specific gravity and is recovered from the bottom of the top dross reservoir 2 into the hot-dip galvanizing tank 1. When the reaction between the top loss and the flux is completed and debris is generated, this debris is removed from the discharge port 1 as much as possible.
1, the rotating shaft 4 is switched from forward rotation to reverse rotation to change the stirring direction, and compressed air is blown from the compressed air injection nozzle 8 to scatter the ash on the bath surface. As a result, the debris on the bath surface gathers near the discharge port 11, flies away from the bath surface, and is sucked by the blower 17. The suctioned debris passes through the transport pipe 15 and is collected in a dust catcher 16, and the passed gas is sent to a wet dust collector 18. On the other hand, the gas generated in the stirring container 3 is sucked through the gas outlet 12 by the dust collection fan 14 and sent to the wet dust collector. In wet dust collectors, dust is generated from the flux in the gas sent to it.
Absorbs and collects HCl and dust. Ash stored in the dust catcher 16 and sludge in the wet dust collector 18 are discharged by cutting dampers 22 and 23, respectively, and collected in collection containers 24 and 25.

In other words, this invention is more efficient than the conventional wet collection method, as the generated debris is carried out using a suction method and collected in a dry state using a dust remover such as a dust catcher. Since the debris is separated and scattered and then suctioned, the debris can be efficiently collected without remaining in the stirring container. Furthermore, since it uses gas transport, there is no mechanical failure of the evacuation mechanism as in conventional systems, and stable operation can be expected at all times. Furthermore, by using a vertical stirring device and driving the rotating shaft for stirring outside the surface of the zinc bath, maintenance and inspection of the device can be facilitated, and the rotating shaft can be easily replaced. Additionally, in the past, the ash treatment equipment was installed around the hot-dip galvanizing tank.
Although the working space was small, this idea has the advantage of being able to secure the current working space since the removal of the ash is carried out using a suction method and is separated from the hot-dip galvanizing tank.

As mentioned above, this invention has great effects, particularly in simplifying the transport and treatment of the reaction product Ash, stabilizing the operation, and improving the recovery efficiency of metallic zinc in Topdross, reducing the unit consumption of zinc, and
It is extremely effective in improving workability.

[Brief explanation of drawings]

The drawing is a schematic explanatory diagram showing one embodiment of this invention. 1... Molten galvanizing tank, 2... Top loss reservoir, 3... Stirring container, 4... Rotating shaft, 5... Stirring blade, 6... Upper lid, 7... Reversible motor, 8...
Compressed air injection nozzle, 10...Flux inlet, 1
1...Atsushi discharge port, 12...Gas discharge port, 1
3... Gas piping, 15... Ash transport pipe, 16
...Dust catcher, 17...Blower, 18
...Wet type dust collector, 20...Topdross, 21...
...Flux.

Claims (1)

[Scope of utility model registration request] A top dross reservoir attached to the end of the hot-dip galvanizing tank so as to communicate with the galvanizing tank is equipped with a vertical stirring vessel that stirs and mixes the top dross and flux using a rotary shaft with vertical stirring blades driven by a motor. A compressed air injection nozzle for spraying compressed air onto the debris generated by the reaction between A top loss separation and recovery device comprising a cleaning tower for gas generated during reaction and gas filtered by the dust remover, which is connected to the stirring vessel.