Converter Dust

Sources of Converter Dust

#Converterdust is produced during converter blowing. Converter is the main steelmaking equipment currently in existence, and has the characteristics of short blowing time and high efficiency. In the process of blowing, a large amount of iron-containing dust is blown away, and the dust enters the dust removal system through the flue. According to different dust removal methods, different types of dust are obtained, and their physical and chemical properties are also different.

The temperature of the dust generated in the converter production process is as high as 1400C. There are generally two dust removal methods currently in existence, one is wet dust removal, that is, 0G dust removal; the other is dry dust removal, that is, LT dust removal. In practice, there are still improved dust removal methods based on the above two methods, but generally speaking, they are divided into wet method and dry method.

The characteristics of converter dust removal

Converter dust removal generally refers to the fine dust obtained from the flue gas produced in the blowing process of the converter after dry dust removal. It has high utilization value. The predecessors have done a lot of research on it. The basic properties were characterized.

Converter dust has the characteristics of high iron content, fine particle size, and large specific surface area. At the same time, it contains a large amount of alkaline oxides such as CaO. Among them, iron exists as ferric oxide and ferric oxide, and the dust surface is positively charged. The ability to absorb negative ions. From a metallurgical point of view, the fine particle size of converter dust, high iron content and high CaO content are its remarkable features.

Utilization of Converter Dust Removal Ash

Converter dust has high iron content, less harmful impurities, and a considerable amount of alkaline oxides such as CaO. It is a good secondary resource. If it is discarded, it will not only occupy a large area of land, pollute the environment, but also waste resources. At present, researchers have done quite a lot of research on the utilization of converter dust.

The current processing and utilization methods of converter dust removal include: production of iron-based pigments, synthesis of non-normal iron, preparation of new ferrite magnetic materials, production of sintered ore, and production of pellets.

1) Production of iron-based pigments

The content of iron oxide or ferrous oxide in converter dust is relatively high, which is an ideal raw material for preparing iron oxide red pigments. Some large domestic steel companies have carried out a lot of research on the preparation of iron-based pigments by using dust, and have achieved application Sexual results, especially in the preparation of iron red. The basic method is to use sulfuric acid to leach Fe in the dedusting ash to obtain a mixed solution of FeSO4 and Fe(SO4)3, neutralize the mixed solution with alkali, and produce iron yellow, iron brown and iron black under different conditions. , iron green and other pigments, iron red pigments can also be obtained after calcining these products at high temperature.

2) Synthesis of non-normal iron

Non-normal iron refers to the metastable phase during the transformation of Fe;O4 to a-Fe2O3, that is, Y-Fe2O3°Because γ-Fe2O3 has a good magnetostriction coefficient and more stable chemical properties than FezO4, it is often used for Substitute FezO4 for magnetic powder. Due to the high content of iron oxide and ferrous oxide in the converter dust removal ash, it is used by researchers to synthesize non-normal iron. The basic method is to use sulfuric acid to leach the iron in the converter dust removal dust to obtain the H2SO4 impregnation solution of the dust removal dust. Add iron powder to the H2SO4 impregnation solution to reduce Fe2+, then neutralize the precipitate with NaOH, and dry the resulting precipitate at a temperature of 200C to obtain the product.

3) Preparation of hard ferrite

Ferrite is a metal oxide with ferromagnetic properties. In terms of electrical properties, the resistivity of ferrite is much larger than that of metal and alloy magnetic materials, and it also has higher dielectric properties. The magnetic properties of ferrite are also shown to have higher magnetic permeability at high frequencies. Therefore, ferrite has become a widely used non-metallic magnetic material in the field of high frequency and weak current.

4) Production of sinter

The converter dedusting ash is mixed with sintering raw materials to generate sintered ore, which is returned to the iron and steel plant for continued use, that is, the large cycle road of blast furnace to converter.

5) Production of pellets

Add appropriate amount of water and a binder with good bonding performance to the converter dedusting ash, prepare pellets on a disc pelletizer or double-roller pelletizer, and return to steelmaking and ironmaking.

In addition, during the pelletizing process, coke powder can be added as a reducing agent to produce self-reducing pellets and return them to the ironmaking pool.

Utilization Trend of Converter Dust Removal Ash

There are currently many ways to utilize converter dust, but the most popular method is to use it as iron-containing resources for "internal circulation", which not only has high utilization efficiency, but also can reduce the cost of raw materials in steel plants and reduce the discharge of waste in steel plants . Sintering ironmaking and pelletizing steelmaking are the two main "internal circulation" processing methods.

Sintering ironmaking is to use the converter as raw material for ironmaking after dedusting and sintering, and follow the big cycle road of blast furnace and converter. The pellet steelmaking method refers to making the converter dust into balls and directly returning to the converter steelmaking, replacing part of the iron ore and used as a slagging agent, that is, a small cycle road. In the process of producing pellets, a double-roller ball press is generally used to press them into balls.