JPH0598338A - Slag reforming agent and method for refoming refining slag - Google Patents

Abstract

PURPOSE:To obtain a slag reforming agent for preventing the development of dust caused by cooling and collapse of the slag produced at the time of refining molten steel by sticking the specific quantity of B2O3 after moisture is added to the slag powder produced in desiliconizing refining of molten iron. CONSTITUTION:The slag produced at the time of executing the pre-desiliconizing refining to the molten iron is charged into a mixer, and by adding the moisture, the moisture is contained at the ratio of 0.1-1.0%. Successively, by adding the B2O3 powder, the B2O3 powder is stuck to the desiliconizing slag so as to become 20-30% in the inner ratio to manufacture the slag refoming agent. This slag reforming agent is used as bedding agent in a ladle pouring the molten steel after the reduction-refining so as to become 0.6-15% B2O3 content, and the molten steel and the molten slag are poured in the ladle. As B2O3 exists in the produced slag, the slag holds the solid-shape even after cooling without powdering by naturally collapsing, such as the ordinary reduction slag at the time of cooling, and this treatment is easy and also this slag can effectively be utilized as roadbed material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slag modifier for refining slag generated in electric furnaces and converters, and a method for modifying refining slag.

[0002]

2. Description of the Related Art Generally, the slag generated in the steelmaking process, especially the reducing slag of an electric furnace, is collapsed and weathered, which is attributed to unreacted free lime, which reacts with water during water cooling and further in the air. It absorbs carbon dioxide, changes to calcium carbonate and becomes fine powder, which causes dust. Therefore, in order to solve this problem, as a method for preventing collapse of slag, as shown in JP-A-55-138016, slate or shale that melts at a temperature lower than the slag temperature is charged and heat is supplied from the outside. Then, the slag composition is changed to prevent the slag from collapsing, and as shown in JP-A-61-295263, metallic aluminum is added to react with other iron oxides in order to reduce the heat source cost. There has been proposed a method of reforming the slag by reducing the cost by using the reaction heat generated as a result. In addition, JP-A-62-162657
As disclosed in the publication, there has been proposed a method of adding boric acid or a boric acid compound to a steelmaking molten slag mainly composed of dicalcium silicate in order to prevent pulverization at the time of cooling the slag, thereby improving the slag.

[0003]

However, as described in JP-A-61-295263, the heat is supplied from the outside, so that the cost is high, and further, JP-A-61-29.
The method using reaction heat as disclosed in Japanese Patent No. 5263 requires metal aluminum or iron oxide in order to cause the thermite reaction, and thus has a problem that the raw material of the modifier and the manufacturing cost are relatively high. there were. In addition, JP-A-62
In the method disclosed in Japanese Patent Laid-Open No. 162657/1992, even if boric acid or a boric acid compound is added to the steelmaking slag, the dust is intense and the loss of the additive is large, and certain refining slag is used for reliable reforming. There was a problem that I could not get it. The present invention has been made in view of the above circumstances, and an object thereof is to propose a slag modifier and a method for modifying refining slag that are relatively inexpensive to manufacture and use and have good addition efficiency.

[0004]

The slag modifier according to claim 1, which is in accordance with the above object, contains a hot metal desiliconization slag to have a water content of 0.1 to 1.0%, and ,
25-30% of B ₂ O ₃ powder is adhered internally to the hot metal desiliconization slag.

According to the second aspect of the present invention, there is provided a method for modifying a smelting slag according to the second aspect, in which 25-30, in internal content, of hot-melted hot metal deslagging slag containing 0.1 to 1.0% of water is contained. % B ₂
B ₂ O _{3 of} slag modified with O ₃ powder attached
An amount of the modifying agent having a concentration of 0.6 to 1.5% is laid on the bottom of the ladle, and refining slag is added to modify the slag.

[0006]

In the slag modifier and the method for modifying the smelting slag of the present invention, it is important to accelerate the reaction of the modifier with the slag and to generate dust when added to the slag. I got the knowledge of. Further, the present invention is to use the hot metal desiliconized slag after the hot metal desiliconization treatment as the base material of the modifier. This is because even if the hot metal demolition slag is in the form of particles, it itself forms a low-melting compound that is easily meltable, and is quickly mixed with the smelting slag after addition. According to the experiment, the melting point of the desiliconized slag containing 30% of B ₂ O ₃ is 970.
It was about ℃.

Then, water is added to the hot metal de-slagging slag.
B ₂ O ₃ powder is adhered and solidified by containing 1 to 1.0% of water or adhering it. This attachment solidified prevent dust generation Konabutsu including B ₂ O ₃ in addition or during bedding in refining slag, yet excellent B ₂ O ₃ of refining slag reforming properties to the surface
Since it is a modifier in which powder is exposed, the effect of modifying B ₂ O ₃ is greatly improved. Moreover, this B ₂ O ₃ effect is synergistic with the above-mentioned characteristics of the hot metal de-slagging slag, and the reforming effect of the refining slag is rapidly and surely exhibited. In addition, B ₂ in the modifier
The O ₃ concentration is 25 to 30% due to its reforming ability, and B ₂ O of slag subjected to the reforming treatment using the modifying agent.
₃ Make the concentration 0.6-1.5%. here,
If the amount of water contained in or attached to the hot metal de-slagging slag is lower than 0.1%, B ₂ O ₃ cannot be sufficiently adhered to the hot metal de-slagging slag particles, leading to dust generation and loss of B ₂ O ₃ when added. On the other hand, B ₂
If the amount of O ₃ is more than 1.0%, rapid heating at the time of addition causes rapid dust generation due to water vapor and loss of B ₂ O ₃ .

In addition, B in the modifier₂O₃The concentration is 25%
If it is less, unstable α'-2CaO ・ SiO₂But γ
-2CaO / SiO₂There is a problem that it easily becomes. one
B in the modifier₂O₃If the concentration is higher than 30%, it is not necessary.
B above₂O₃It becomes an addition, and there is an economic problem. next,
B in refined slag after reforming₂O₃Concentration of 0.6%
If it is low, there is a problem that the slag reforming effect becomes unstable.
On the contrary, if it is more than 1.5%, B is more than necessary. ₂O₃With addition
There are financial problems.

The slag modifier contains 25 to 40
% CaO, 20-30% SiO ₂ and 2-4% A
because it contains l ₂ O _3, as well as tempered components of the slag, to promote diffusive mixing of the molten steel slag B ₂ O _3. If it exceeds this range, the basicity will become high and the fluidity of the slag will deteriorate, and in some cases the above-described stable mineral composition may not be modified.

[0010]

EXAMPLES First, in producing a slag modifier according to an example of the present invention, hot metal desiliconization slag is prepared. The particle size of this hot metal desiliconization slag is as shown in Table 1.

[0011]

[Table 1]

Next, the hot metal desiliconization slag is put into a mixer and water is added so as to have a water content of 0.1 to 1.0%, and then 25 to 30% of B ₂ O ₃ is added as an internal content. It is manufactured by mixing B ₂ O ₃ into the crushed hot metal desiliconization slag that has been stirred and crushed substantially uniformly. In this example, hot metal desiliconization slag was used as the raw material for the slag modifier, but if the overall components fall within the above range, other raw materials or raw materials prepared by mixing in shortages may be used. It can be used even if there is.

When using this slag modifier, the slag modifier is put in a slag pan in advance, but the amount of the slag modifier is 1 to 7% (preferably 3 to 7) of the slag to be treated.
5%). Next, the molten steelmaking slag is received in the slag pan, in which case the slag modifier is agitated by the falling energy of the molten steelmaking slag at the time of slag to lower the melting point of the slag and at the same time. Is modified.

When gradual cooling is continued for 24 hours, the slag without addition of the slag modifier is early and after 4 to 5 hours all are pulverized, which causes difficulty in treatment work, but the slag modifier is added. The slag thus produced is sufficiently prevented from being pulverized and does not disintegrate even if it is immersed in water thereafter. Here, an experiment was conducted in order to confirm the action and effect of the present invention. The results will be described. First, the components of the slag to be treated are shown in Table 2, and Table 3 shows the experimental slag modifier ( A), (B),
The component (C) and the result of X-ray diffraction are shown.

[0015]

[Table 2]

[0016]

[Table 3]

Therefore, according to the result of X-ray diffraction, the γ-type dicalcium silicate (γ-2CaO.SiO ₂ ) which causes the powdering and disintegration in the electric furnace reducing slag is converted to the glenite (GEHLENITE, 2CaO.
SiO ₂ · Al ₂ O ₃ ) and is considered to be stable. For (B) and (C), the post-reforming Gerenite ratio is as high as 90% or more, and for (A), ilbitite (ILVAITE, CaO.Fe ₂ O ₃ (FeO
It is presumed that H) and SiO ₂ ) and gehlenite are stable in most cases. Further, it has been clarified that the modifier based on hot metal desiliconization slag is sufficiently applicable as a dusting inhibitor after slag treatment. Since B ₂ O ₃ (boric anhydride) is relatively expensive as a raw material, it is considered that 30% or less of the slag modifier is sufficient. Further, in the above-mentioned embodiment, the slag modifier is of the put type which is put in the bottom of the slag pan in advance, but it may be blown by gas or put on top.

[0018]

EFFECTS OF THE INVENTION The slag modifier and refining slag reforming method according to claims 1 and 2 are treated because they can prevent the slag from collapsing in the steelmaking process, which is disintegrated if left as it is. The slag can be used as a roadbed material, and the application range of slag is expanded. And, it has become possible to provide a slag modifier which is relatively low in manufacturing and use costs as compared with conventional products and has good addition efficiency. Furthermore, since the hot metal desiliconization slag, which has not been effectively used in the past, can be used, the usage of slag is further expanded.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Saito 1-3-1 Otani, Yawatahigashi-ku, Kitakyushu, Fukuoka Prefecture Irie Kosan Co., Ltd.

Claims (2)

[Claims] 1. Hot metal desiliconization slag is impregnated with water for 0.1 to 10.
A slag modifier characterized by having a water content of 1.0% and adhering 25 to 30% of B ₂ O ₃ powder in the internal content to the hot metal desiliconization slag. 2. A slag modified by depositing 25 to 30% of B ₂ O ₃ powder in the internal content on the hot metal desiliconized slag containing 0.1 to 1.0% of water. ₂ O ₃ concentration is 0.
A method for modifying a smelting slag, which comprises laying a modifying agent in an amount of 6 to 1.5% on the bottom of a ladle, adding refining slag, and modifying the slag.