JPH028002B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for separating and recovering zinc from Zn-containing dust. Blast furnace dust usually contains about 2 to 4% Zn, but also contains a large amount of Fe. For this reason, it is generally reused as an Fe source for blast furnaces, but in this case it is necessary to remove Zn from the dust. This is because if Zn remains contained, a so-called Zn attack problem will occur when used as an Fe source, but this Zn removal has the disadvantage of requiring a large amount of cost. That is, two methods, called a dry processing method and a wet processing method, are currently in practical use as methods for removing Zn from dust.
The dry processing method is a method in which Zn compounds in dust are reduced using, for example, dust reduction equipment to volatilize and remove Zn, but this processing is disadvantageous not only in terms of equipment costs but also in terms of energy costs. On the other hand, the wet method involves bringing the dust into contact with, for example, NaOH.
This method involves dissolving and separating _the Zn content as Zn(OH) ^2-4 , which also reduces equipment costs.
The use of NaOH not only poses problems in terms of running costs, but also the residual Na poses a problem when the residue after Zn removal is reused as blast furnace raw material. The purpose of the present invention is to provide a method for rationally and effectively separating and recovering zinc from Zn-containing dust using a method completely different from conventional methods. Zn-containing dust is blown in using a lance, and the zinc oxide contained in the dust is reduced by C and Si in the hot metal.
It is characterized in that it is separated as Zn vapor, collected by a dust collector connected to the sealed container, and concentrated. That is, the desiliconization treatment of hot metal is usually carried out using sintering dust generated in the sintering process of blast furnace raw materials, but the present invention uses Zn as a desiliconizing agent for the desiliconization treatment of hot metal. Adding contained dust,
It allows the following reaction to proceed. Based on the reaction Si + 2ZnO → SiO ₂ + 2Zn↑ ...... Si in the hot metal is oxidized and separated as slag, and at the same time zinc oxide (ZnO) in the dust is reduced and volatilized as Zn vapor. Zn
Since Fe has a lower boiling point (918℃) than Fe, it evaporates from the hot metal. Through the reaction of Si + 2FeO → SiO ₂ + 2Fe......, as above, Si in the hot metal is oxidized and separated in the form of slag, and iron oxide (FeO) in the dust is reduced, and the Fe content is directly added to the hot metal. to recover. All of the above are Si oxidation reactions and are exothermic reactions, so there is no need to supply energy from outside during the reaction, which is not only advantageous in terms of energy costs, but also allows the Fe content in dust to be recovered directly. Therefore, the collection efficiency is extremely high. Specifically, the method of the present invention described above can be carried out as follows. Dust collector 4 shown in Figure 1
In the injection extraction equipment, Si-containing hot metal 1 tapped from a blast furnace is stored in a closed container 3, and Zn-containing dust is blown into the hot metal 1 using a lance 2. By this operation, Si in the hot metal is reduced to slag 1
To a, the Fe content in the dust is recovered into the hot metal 1, and the Zn content that evaporated at the same time reaches the dust collector 4 along with the scattered particles, where it is separated in the form of dust containing ZnO as the main component. It is. In other words, this dust is concentrated Zn dust that does not contain Fe. According to the results of the present inventors, blast furnace dust having the components shown in Table 1 was added to torpedo hot metal (300T) containing 0.5% Si by the method shown in Fig. 1 to perform the Si removal treatment. , hot metal Si content from 0.5% to 0.2
% [(Si concentration before reaction - Si concentration after reaction) x 100/Si concentration in hot metal before reaction] was investigated and found that it was 80 to 90, the same as when using conventional sintered dust. % high efficiency was recorded. The composition of the Zn concentrated dust produced in this case was as shown in Table 2, and since it contains 50% or more of Zn, it can be sold externally as a Zn raw material.

【table】

[Table] As is clear from the above explanation, the method of the present invention can separate and recover the Zn content in Zn-containing blast furnace dust as concentrated Zn dust, and also directly transfer the Fe content in the above dust into hot metal.
Therefore, it can be recovered at a high yield. At the same time, Si in hot metal can be removed in the form of slag with high efficiency. Moreover, since it utilizes the exothermic oxidation reaction of Si, it is much more advantageous and economical in terms of energy costs than conventionally known methods for removing Zn from blast furnace dust (wet method, dry method). In addition, there is a great practical advantage in that the existing hot metal desilicon treatment equipment can be used as is. Therefore, it can be said that the present invention provides an extremely advantageous method of utilizing blast furnace dust.

[Brief explanation of drawings]

FIG. 1 is a schematic process diagram illustrating a specific example of the method of the present invention. In the figure, 1: hot metal, 1a: slag, 2: lance,
3: Airtight container, 4: Dust collector.

Claims (1)

[Claims] 1 Using a lance in hot metal stored in a closed container
Zn-containing dust is injected, and the zinc oxide contained in the dust is reduced by C and Si in the hot metal.
A method for separating and recovering the zinc content of Zn-containing dust, which comprises separating the zinc content as vapor, collecting it using a dust collector connected to the airtight container, and concentrating it.