JPH10317018A - Blast furnace dust dezincing method - Google Patents

Abstract

(57) [Problem] To provide a method for removing zinc from blast furnace dust and recovering it as blast furnace raw material that can be reused. (A) High-pressure water is injected from one end of a container through a nozzle into the container, and air sucked into the high-pressure water from the nozzle is taken into the injection water, and water is introduced into the container. Generating a two-fluid jet of air and air;
(B) adding a slurry-like blast furnace dust to the two-fluid jet stream in the container, and using a stirring force of the two-fluid jet stream, a portion having a high zinc content attached to the particles of the blast furnace dust. From the particles. Further, the exfoliated portion having a high zinc content can be introduced into a wet cyclone to separate dust particles having a high zinc content and dust particles having a low zinc content.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of treating a slurry blast furnace dust generated from a blast furnace of an ironworks by improving the separation and recovery of a zinc component contained in the slurry blast furnace dust and effectively utilizing the blast furnace dust. About.

[0002]

2. Description of the Related Art Blast furnace dust cannot stay in the furnace of a blast furnace due to its small particle size, and is accompanied by gas in the furnace which blows up from the lower part of the furnace to the furnace top. This is a general term for powder that has jumped out. After jumping out of the blast furnace, it is collected as a slurry blast furnace dust to be collected by a scrubber.

[0003] In recent years, zinc in blast furnace dust is mainly present as zinc oxide with an increase in the amount of scrap used, and the content thereof tends to increase. The use of blast furnace dust having a high zinc content as a raw material for blast furnaces hinders the operation of the blast furnace, and its reuse has been limited. On the other hand, it is not desirable to directly dispose of such blast furnace dust from the viewpoint of environmental conservation. Therefore, it is required to establish a method of separating and recovering zinc oxide (hereinafter simply abbreviated as zinc) from blast furnace dust and reusing blast furnace dust as blast furnace raw material.

[0004] The method of separating zinc from blast furnace dust is roughly classified into i) by dissolution extraction and ii) by wet classification. Regarding the dissolution extraction method of i), Japanese Unexamined Patent Publication (Kokai) No. 3-177522 discloses "a method for dezincing blast furnace dust and a method for recovering the zinc".
No. 3 discloses "Blast furnace dust dezincing method".

[0005] The wet classification of ii) is disclosed in
JP-A-81406, "Method of treating blast furnace secondary ash", and JP-A-53-81479, "Method of treating blast furnace dust"
Is disclosed. In particular, in Japanese Patent Application Laid-Open No. 53-81479, an ultrasonic irradiator is used for the purpose of improving the separation and recovery rate of zinc (the same publication, FIG. 1).

[0006] In the above-mentioned dissolution extraction method, JP-A-3-13-1
As described in Japanese Patent No. 77522, when a large amount of blast furnace dust is treated, a large amount of an acid solution is used, so that there is a problem in economic efficiency. Further, in the publication, the composition of the effluent obtained from the exhaust gas cooling tower in the flue gas desulfurization step of the sintering plant greatly varies depending on the operation. For this reason, pH management is difficult. Further, in the conventional wet classification, the separation and recovery rate of zinc is 75 to 85%, and it is necessary to improve the recovery rate.

Further, the ultrasonic irradiator disclosed in Japanese Patent Application Laid-Open No. 53-81479 has to increase the size of the ultrasonic irradiator and increase the output when processing a large amount of dust. However, there was a problem in terms of economy.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned problems, and makes it possible to economically separate and recover zinc oxide from slurry blast furnace dust with more efficient and simpler equipment than before. Is provided.

[0009]

Means for Solving the Problems The inventors of the present invention have conventionally used a jet pump used for transporting sand, sludge, or the like, which has a very high stirring force in the jet flow, and uses this as a powder separation method. Has found that an effective separation method becomes possible.

Therefore, the following invention was conceived with the idea that a portion having a high zinc content was separated from the particles of the blast furnace dust by utilizing the stirring force of the jet flow in the jet pump. became.

A first aspect of the present invention provides a method for dezincing blast furnace dust, comprising the following steps. (A) High-pressure water is injected into the container from one end of the container through a nozzle, and air sucked by the high-pressure water from the nozzle is taken into the injected water, and water and air are injected into the container. A step of generating a fluid jet, and (b) adding slurry-like blast furnace dust to the two-fluid jet in the container, and using the stirring force of the two-fluid jet to separate zinc oxide from the particles of the blast furnace dust. Removing the high content portion from the particles.

In this method, high-pressure water is blown out from a nozzle into a container, air is sucked using the negative pressure, and a two-fluid jet of water and air is generated in the container. The slurry is washed with stirring to remove the zinc-rich portion adhering around the blast furnace dust particles, thereby improving the separation and recovery rate of zinc.

This method is excellent in that the stirring force by the two-fluid jet flow is stronger than that of ultrasonic irradiation or the like and not only disperses the dust particles but also peels off zinc fused to the blast furnace dust particles. .

According to a second aspect of the present invention, a particle group containing a portion having a high zinc content, which has been exfoliated in the first aspect, is further introduced into a wet cyclone, and a dust particle group having a high zinc content and a dust group having a high zinc content are further introduced. A method for dezincing blast furnace dust, comprising a step of separating into small dust particles.

According to the first aspect of the present invention, the blast furnace dust containing particles having a high concentration of zinc attached to the periphery of the blast furnace dust particles separated from the blast furnace dust particles according to the first invention is further introduced into a wet cyclone to contain zinc. It separates into dust particles having a high amount and dust particles having a low zinc content.

In the wet cyclone, due to centrifugal force, based on the difference in particle density, a high zinc content dust containing a high zinc content portion exfoliated and a low zinc content low Separates from zinc-containing dust.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an outline of an apparatus for dezincing blast-furnace dust in the practice of the present invention. The slurry-like blast furnace dust 2 is supplied from a transport vehicle to a container 34 of a two-fluid slurry machine 35 via a reservoir tank 4 and a feed tank 6. Two-fluid slurry machine 3
In 5, after blowing out the high-pressure water 30 from the nozzle 33, the air 32 is mixed to form a two-fluid jet.

When the slurry-like blast furnace dust 2 is added to the two-fluid jet, the high-energy air and water two-fluid jet separates the high zinc content portion adhering to the periphery of the blast furnace dust particles. be able to. The resulting slurry is desirably fed to a wet cyclone 10 and separated into high zinc dust 12 and low zinc dust 14.

FIG. 2 shows an outline of the method according to the present invention. In the container of the two-fluid slurry machine, a two-fluid jet of water and air is generated while sucking air into high-pressure water. Slurry blast furnace dust is added to this. Blast furnace dust discharged from the blast furnace top is collected by a scrubber and is supplied in a slurry state.

In the container of the two-fluid slurry machine, air is sucked by high-pressure water to generate a two-fluid jet of air and water. Slurry blast furnace dust is added to the two-fluid jet. With the two-fluid jet, a portion having a high zinc concentration attached to the periphery of the blast furnace dust particles can be separated.

After the portion having a high zinc concentration is peeled off, it is separated into low zinc content dust and high zinc content dust by a wet cyclone based on a difference in specific gravity. The low zinc content dust can be reused as a raw material for the blast furnace after being subjected to a dehydrator because of its low zinc content. The high zinc content dust is not desirable as a blast furnace raw material because of its high zinc content, and is used as a cement raw material after being dewatered.

FIG. 3 shows the material balance of the method according to the invention. The figure shows the material balance before and after dezincification and the zinc content in each part when slurry blast furnace dust is supplied to these devices. According to the method of the present invention, the zinc content in the high zinc slurry is about 2.5%
It is.

FIG. 4 shows the process of calculating the zinc removal rate and the results when the present invention is carried out. As shown in FIG.
When dezincing was performed using the method according to the present invention, the zinc content of the low zinc slurry was about 0.1%, which was 1/3 of the zinc content of the conventional low zinc slurry. Therefore,
Most of this low zinc slurry can be reused as blast furnace raw material. In addition, the zinc removal rate reached about 91%.

FIG. 5 shows the concept of an apparatus for explaining a conventional method. The figure shows the material balance before and after dezincification and the zinc concentration in each part when slurry blast furnace dust is supplied to these devices. Traditionally, simply
The slurry blast furnace dust was supplied to the wet cyclone as it was. As a result, the zinc content in the high zinc slurry reached only about 2.0%.

FIG. 6 shows the calculation process and the result of the zinc removal rate in this case. As shown in FIG. 6, the zinc removal rate in the low zinc slurry was only about 73%. This low zinc slurry had a zinc content of about 0.3%, which was not very desirable as a blast furnace raw material. Therefore, much of this low zinc slurry could not be used as a blast furnace raw material.

[0026]

As described above, the method of the present invention has the following advantages. (1) Since the two-fluid slurry machine used in the present invention utilizes simple equipment, it is extremely economical and can greatly reduce costs. (2) According to the method of the present invention, dezincing of slurry blast furnace dust can be carried out at a higher dezincing rate than before. (3) The slurry-like blast furnace dust dezincified by the method of the present invention has a low zinc content, so that it can be reused in large quantities as a blast furnace raw material and has an effect of saving resources.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of an apparatus required for dezincing slurry blast furnace dust in carrying out a method of the present invention.

FIG. 2 is a diagram showing an outline of a method according to the present invention.

FIG. 3 is a diagram showing the concept of an apparatus for explaining a method according to the present invention.

FIG. 4 is a diagram showing a calculation process and a result of a zinc removal rate by a method according to the present invention.

FIG. 5 is a diagram showing the concept of an apparatus for explaining a conventional method.

FIG. 6 is a diagram showing a calculation process and a result of a zinc removal rate according to a conventional method.

[Description of Signs] 2 Slurry blast furnace dust 4 Reservoir tank 6 Feed tank 10 Wet cyclone 12 High zinc-containing dust 14 Low zinc-containing dust 30 High-pressure water 32 Air 33 Nozzle 34 Container 35 Two-fluid slurry machine

Claims (2)

[Claims] 1. A method for dezincing blast furnace dust, comprising the following steps: (A) High-pressure water is injected into the container from one end of the container through a nozzle, and air sucked by the high-pressure water from the nozzle is taken into the injected water, and water and air are injected into the container. Generating a fluid jet, (b) adding slurry-like blast furnace dust to the two-fluid jet in the vessel,
A step of exfoliating, from the particles of the blast furnace dust, particles having a high zinc content by the stirring force of the two-fluid jet stream. 2. The method according to claim 1, further comprising the step of introducing the exfoliated portion having a high zinc content into a wet cyclone to separate a dust particle group having a high zinc content and a dust particle group having a low zinc content. The method for dezincing blast furnace dust according to claim 1, characterized in that: