JPH101725A - Dust treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust treating device which can recover zinc and lead separately in high yield from the dust stuck to a dust collecting device of an arc furnace for steelmaking. SOLUTION: In this dust treating device, metallic oxides are reduced to vaporize metallic components by heating the dust containing the metallic oxides such as zinc oxide and lead oxide together with reducing material in a closed vessel 1 under vacuum condition. In this case, the metallic components are liquefied by passing gas sucked from the closed vessel 1 through a piping 20 held at 419-550 deg.C, and dripped down into a liquid basin 22 provided at the lower part of the piping. A throat 24 is allowed to droop from the bottom part of the liquid basin into a liquid storing vessel 23 whose liquid surface is reliesed to the atmosphere and the liquefied metal in the liquid basin is allowed to flow into the liquid storing vessel through the throat. Then, the temp. of the liquefied metal is held at 419-450 deg.C and the zinc 51 and the lead 50 are separated into the upper and the lower parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust processing apparatus for separating and recovering valuable metals such as lead and zinc from dust adhering to a dust collecting apparatus provided in a waste gas passage of an arc furnace for steelmaking, for example. It is about.

[0002]

2. Description of the Related Art A large amount of dust accumulates in a waste gas passage such as an electric furnace or a scrap preheating device in a steelmaking plant and a dust collecting device thereof, and the dust contains lead oxide (Pb).
O) and zinc oxide (ZnO). Therefore, if this dust is discarded as it is, there is a risk that resources will be wasted and the environment will be destroyed. Therefore, it is desired to separate and collect these valuable metals from dust for effective use.

[0003] Conventionally, a reducing agent is mixed with the above-mentioned dust containing a metal oxide, and this is heated and sealed in a closed container.
It has already been attempted to reduce the metal oxide in the dust by stirring, evaporate the metal component, and recover the metal component in the gas by passing the gas discharged from the closed vessel through a condenser. ing.

However, in the conventional method for separating and recovering metal components, the recovery rate is low, and metal components other than zinc and lead are recovered in a unified manner. The situation required purification to increase the purity.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a dust processing apparatus capable of recovering zinc and lead at a high rate and in a separated state.

[0006]

For this purpose, the present invention provides a method for heating a dust containing a metal oxide such as zinc oxide and lead oxide in a closed vessel together with a reducing material in a vacuum to form the metal oxide. Gas at 419 ° C. in a dust treatment device for reducing the metal components and evaporating the metal components.
The metal component is liquefied by passing through a pipeline maintained at a temperature of ５550 ° C. and dropped into a liquid reservoir provided at the lower part of the pipeline. A throat is drooped from the bottom of the liquid reservoir, and the liquefied metal in the liquid reservoir is discharged to the liquid storage tank through the throat,
The temperature of the liquefied metal in the storage tank is maintained at 419 ° C. to 450 ° C., and zinc and lead are vertically separated.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a closed vessel formed by a heat insulating furnace wall, and 2 denotes a treatment pot disposed in the closed vessel 1. Reference numeral 4 denotes a stirrer that causes the blades 5 to hang down in the processing pot 2 and rotate the blades 5 in the processing pot 2 by driving a motor 6. Reference numeral 7 denotes an opening / closing stopper provided at the bottom of the processing pot 2, reference numeral 8 denotes a cylinder for opening and closing the opening / closing stopper 7 to open and close the discharge port 9, and reference numeral 10 denotes a heater provided in the closed container 1.

[0008] Reference numeral 20 denotes a U drawn out of the closed container 1.
A heater 21 for adjusting the temperature is provided on the outer periphery of the pipe 20. Reference numeral 22 denotes a liquid reservoir provided at a lower portion of the conduit 20, and a throat 24 hangs down from the bottom of the liquid reservoir 22. Reference numeral 23 denotes a liquid storage tank whose liquid surface is open to the atmosphere, and the lower end of the throat 24 is immersed in the liquid storage tank 23. Reference numeral 29 denotes a heater provided in the liquid storage tank 23. Reference numeral 25 denotes a temperature indicating controller which detects the temperature of the pipeline 20 by a sensor 26 and controls the heater 21 to maintain the temperature of the pipeline 20 at 419 ° C. to 550 ° C. This is a temperature indicating controller that detects the temperature of the liquefied metal in the liquid tank 23 and controls the heater 29 to maintain the temperature of the liquefied metal at 419 ° C. to 450 ° C.

Reference numeral 30 denotes an oil-drop-spray-type cooling / filter provided at the end of the pipe 20, and reference numeral 32 denotes a bag filter provided downstream of the cooling / filter 30. Reference numeral 33 denotes a catalyst made of a precious metal mesh such as platinum or titanium / vanadium provided on the secondary side of the bag filter, and reference numeral 34 denotes a vacuum suction pump provided at the extreme end.

In the cooling / filtering device 30, a filtering net 36 made of a metal net is stretched horizontally in a vertical cylindrical body.
A gas inlet 37 is opened on the lower side wall of the filter, a gas outlet 38 is opened on the upper side wall, and nozzles 39 and 40 are provided above and below the filter net 36 so that the oil such as engine oil and hydraulic oil is not used. Volatile cooling oil is sucked out of the body by the pump 41 and circulated through the nozzles 39 and 40 so that the cooling oil can be sprayed from the nozzles toward the filtration network 36. Reference numeral 42 denotes a strainer provided at the bottom of the container.

[0011] In the dust processing apparatus configured as described above,
Dust containing a metal oxide such as electric furnace dust is stored in a processing pot 2 together with a reducing agent in the form of a metal powder such as iron powder, and the heater 10
This is stirred by the stirrer 4 while being heated by heating, and the dust is heated to about 900 ° C., and the inside of the sealed container 1 is evacuated (depressurized) by the operation of the vacuum suction pump 34 so that Of zinc oxide, lead oxide, etc., to evaporate metal components.

Then, when the gas is passed through the pipe 20, the pipe 20 has a temperature (4 ° C. or lower) which is lower than the boiling point of zinc and higher than the melting point.
(19 ° C. to 550 ° C.).
Zinc and lead are liquefied and adhere to the inner surface of the substrate and form droplets and accumulate in the liquid reservoir 22. Then, the liquefied metal gradually flows down to the liquid storage tank 23 through the throat 24 by a balance between the pressure in the pipe 20 applied to the liquid surface of the liquid reservoir 22 and the atmospheric pressure applied to the liquid surface of the liquid storage tank 23. The liquefied metal in the liquid storage tank 23 is maintained at 419 ° C. to 450 ° C., so that the lead 50 sinks due to the difference in specific gravity while keeping the liquid state, and the zinc 51 is separated thereon. For this reason, zinc 5
1 can be recovered, and lead 50 can be recovered from the lower part. In order to promote this separation, it is desirable to set the above temperature strictly to 419.5 ° C. from the phase diagram of the alloy of both metals.

Further, the gas passed through the pipe 20 by the suction of the vacuum suction pump 34 and further led to the cooling / filter 30 is further sprayed with cooling oil by the cooling / filter 30 to be further cooled by 250. The temperature is cooled to not more than 0 ° C., and the metal components remaining in the gas are solidified, and the solid matter adheres to the filter net 36 together with the oil droplets, and can be collected on the strainer 42.

[0014]

As described above, according to the dust treatment apparatus of the present invention, the metal oxide in the dust is reduced to evaporate the metal component, and the gas is passed through a pipe maintained at a predetermined temperature range. By keeping the temperature of the liquefied metal at a predetermined temperature by flowing the liquefied metal through a throat to a storage tank, there is a beneficial effect that zinc and lead can be efficiently separated and recovered.

[Brief description of the drawings]

FIG. 1 is a piping system diagram of a dust processing apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed container 2 Processing pot 10 Heater 20 Pipeline 21 Heater 22 Liquid reservoir 23 Storage tank 24 Throat 25 Temperature indicator controller 26 Sensor 27 Temperature indicator controller 28 Sensor 29 Heater 30 Cooling / filtering device 32 Bag filter 34 Vacuum suction pump 50 Lead 51 Zinc

Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C22B 19/30 C22B 19/30 F27D 17/00 104 F27D 17/00 104G

Claims (1)

[Claims] 1. A dust treatment in which dust containing metal oxides such as zinc oxide and lead oxide is heated in a closed vessel together with a reducing material in a vacuum to reduce the metal oxides and evaporate metal components. In the apparatus, the metal component is liquefied by passing the gas sucked from the closed vessel through a pipe maintained at a temperature of 419 ° C. to 550 ° C., and is dropped into a liquid reservoir provided at a lower part of the pipe. Drop the throat from the bottom of the reservoir into a reservoir whose surface is open to atmospheric pressure,
The liquefied metal in the liquid reservoir is allowed to flow through the throat to the storage tank, and the temperature of the liquefied metal in the storage tank is set to 419 ° C.
A dust processing apparatus characterized in that zinc and lead are vertically separated while being maintained at -450 ° C.