JP2004076148A - Steelmaking raw materials - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method by which collected dust generated on converter operation which is not effectively recycled since it comprises moisture and consists of fine grains can be worked into an iron raw material of high quality in a high yield. <P>SOLUTION: The iron raw material for electric furnace steel making and for casting production is obtained by adding cement and/or starch to dust generated/collected in a converter and coke powder generated/collected in a coke furnace, performing kneading and thereafter compacting the same by a press. <P>COPYRIGHT: (C)2004,JPO

Description

又、使用したコークス炉集塵粉、即ちコークス微粉の成分分析値を表−２に示す。
【表−２】

なお、バインダーとして使用したセメントは通常のポルトランドセメントを使用した。又、スラグの流動性を改善するために少量の蛍石を使用することとした。
【０００８】
【実施例】
前述の各材料を以下の割合で配合し、簡易ミキサーで充分混練した。
集塵ダスト　；５００ｋｇ
コークス粉　；　２０ｋｇ
セメント　　；　５０ｋｇ
蛍石　　　　；　５ｋｇ
混練後、直ちに振動プレス機にて成型を行った。なお金型は約８００ＣＣのものを使用した。
５０個の正常な成型物を製造したが、平均単重は３．５ｋｇであった。
【０００９】
次に溶解歩留まりを確認するために、１００ｋｇの高周波誘導炉を用いて３回の溶解試験を行った。一回当たりの成型物の装入量は２０個とした。
完全に溶解し約３０分保持したのち、電源を切りそのまま冷却した。凝固後メタルを取り出し重量を測定した。
各々のメタル量は５２．７ｋｇ、５４．０ｋｇ、５１．２ｋｇであり平均の鉄歩留まりは９４．７％であった。
【００１０】
【発明の効果】
かくしてこの発明によれば、転炉集塵ダストを必要あらば同じく製鉄所にて副生しているコークス粉と共に成型することにより、ハンドリングが容易で、且つ溶解歩留まりの優れた良質な鉄原料を得ることが出来る。
【図面の簡単な説明】
【図１】この発明の製造工程を示す図である。
【符号の説明】
１．乾燥炉
２．ミキサー
３．プレス機
４．養生炉[0001]
TECHNICAL FIELD OF THE INVENTION
After the coke powder generated from the coke oven in the steelworks and collected by the dust collector as well as the dust generated from the converter in the steelworks in the steelworks and collected by the dust collector, was put into a mixer together with the binder and kneaded well, The present invention relates to an iron raw material formed using a press machine.
More specifically, it is an inexpensive and high-quality raw material suitable for electric furnace steelmaking and casting production that does not contain impurities such as phosphorus, sulfur, and heavy metals and has a uniform shape and is easy to handle.
[0002]
[Prior art]
Exhaust gas generated in large quantities during decarburization in a converter is a gas recovery system, unlike the conventional method. Therefore, most of the collected dust is only slightly oxidized on the surface of the particles and metallic iron The form is maintained.
However, the dust collected is several mm. Or, it is fine powder smaller than that, and since it is usually collected and collected by a venturi scrubber, it has about 20% moisture.
Therefore, a part is reduced to the converter as iron raw material, and although it is used as a raw material for electric furnace steelmaking, it is a fine powder, causing a loss at the time of handling. There are problems such as oxidation and slag.
Therefore, most of the dust is brought into the sintering plant in the steel mill and converted into sinter, and is reduced to the blast furnace as a substitute for iron ore.
[0003]
[Problems to be solved by the invention]
As described above, an effective recycling method has not been established because of the fine powder despite the fact that it is a good quality iron source with few impurities.
In particular, the conventional method of sintering in a sintering plant and returning to the blast furnace is a double method of oxidizing the metallic iron in the dust in the sintering process into iron oxide and reducing it to metallic iron again in the blast furnace. You are wasting.
Therefore, the present invention proposes a high-quality iron raw material that does not cause loss during handling and melting by blending carbon necessary for reducing iron oxide covering the dust surface and molding it with a vibration press or the like.
[0004]
[Means for Solving the Invention]
First, the dust collected by the dust collector is dried using a dryer such as a rotary dryer. However, when a binder such as cement is mixed in a later step, since water is added, there is no problem that a small amount of water remains in the dust.
The dust after drying is put into a mixer together with dust and coke dust from a coke oven and cement and / or starch, if necessary, and mixed well.
The mixing amount of the dust collecting coke is desirably 1.50 times or less the theoretical amount required for reducing iron oxide in the dust. Carbon is an indispensable element at the time of steel making or casting production, so that there is no particular problem even if the compounding amount is too large.
However, if the amount is too large, molding is difficult and sufficient molding strength may not be obtained, so that the blending amount is limited.
Next, as a binder, cement or starch or a mixture thereof is desirable. This is because it is inexpensive and can obtain sufficient strength even with natural curing.
Further, additives such as a binder should be kept as small as possible in order to dilute the iron content of the molded product and increase the amount of slag produced. Specifically, it varies depending on the properties such as the particle shape and size of the dust, but is desirably from several percent to less than 10%.
[0005]
The mixture discharged from the mixer is immediately applied to a vibrating press and molded. There is no problem if the molded product has a size that does not hinder the dissolution, but if it is too large, strength is not obtained and curing takes time.
On the other hand, if the size is too small, the productivity of molding is deteriorated, so that the weight per piece is preferably 1 to 10 kg.
The shape is not limited, but a rounded shape that is not easily damaged during handling is desirable.
[0006]
The molded product can be strengthened by curing. The curing may be a so-called natural curing that is left indoors, but requires a large space because it takes time. It is also effective to use a band dryer type curing machine to reduce time and space.
The cured moldings are stored indoors, and loaded onto trucks using magnets or shovels as necessary.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be specifically described with reference to examples.
Table 1 shows the component analysis values of the converter dust collected in this test.
[Table-1]

Table 2 shows the component analysis values of the used coke oven dust, that is, the coke fines.
[Table-2]

Note that ordinary Portland cement was used as the cement used as the binder. In addition, a small amount of fluorite was used to improve the fluidity of the slag.
[0008]
【Example】
Each of the above-mentioned materials was blended in the following ratio and kneaded sufficiently with a simple mixer.
Dust collected; 500 kg
Coke powder; 20kg
Cement; 50kg
Fluorite; 5kg
Immediately after kneading, molding was performed using a vibration press. The die used was about 800 CC.
Fifty normal moldings were produced, but the average unit weight was 3.5 kg.
[0009]
Next, in order to confirm the melting yield, a melting test was performed three times using a 100 kg high-frequency induction furnace. The charging amount of the molded product at one time was 20 pieces.
After completely dissolving and holding for about 30 minutes, the power was turned off and the system was cooled as it was. After solidification, the metal was taken out and its weight was measured.
The amount of each metal was 52.7 kg, 54.0 kg, and 51.2 kg, and the average iron yield was 94.7%.
[0010]
【The invention's effect】
Thus, according to the present invention, if necessary, the dust collected from the converter is molded together with coke powder by-produced at the steel mill as well, so that a high-quality iron raw material that is easy to handle and has an excellent melting yield can be obtained. Can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a manufacturing process of the present invention.
[Explanation of symbols]
1. Drying oven2. Mixer 3. Press machine4. Curing furnace

Claims (4)

A raw material for electric furnace steelmaking and casting production, which is formed by kneading dust collected from a converter and fine coke generated and collected from a coke oven together with a binder, if necessary, and then molding with a press. 2. The method according to claim 1, wherein the amount of the fine coke is not more than 1.50 times the theoretical amount required to reduce the iron oxide contained in the dust. The raw material for steelmaking described in 1. 2. The binder according to claim 1, wherein the binder is cement and / or starch. The raw material for steelmaking described in 1. 2. The molding according to claim 1, wherein the unit weight of the molded product is from 1 kg to 10 kg. The raw material for steelmaking described in 1.

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