JPH02175812A - Slag cutting ball - Google Patents

Abstract

PURPOSE:To obtain a slag cutting ball having sufficient refractory layer at a low cost by coating outer surface of a core metal with the prescribed refractory using converter dust, waste brick, etc., to adjust this to the prescribed bulk density. CONSTITUTION:This slag cutting ball 1 is formed dy covering the outer surface of the core 2 with the refractory. This refractory is formed by adding binder to iron powder, converter dust, iron scrap, granular iron and waste brick. Then, the above ball 1 is adjusted to blending ratio of 30-50wt.% the above refractory, 70-50% metal iron and the bulk density of 4-5.5.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a slag cant ball used to prevent slag from flowing out together with molten metal at the final stage of steel tapping in a converter.

(Prior art) This type of slag cant ball is, for example,
Various proposals have been made regarding the shape of the ball, such as forming irregularities on the outer surface of the ball, as shown in Japanese Patent No. 85, or making the entire ball slightly flat. However, as shown in Japanese Patent Application Laid-Open No. 49-89609, most of the internal structures used steel as a core material for adjusting the specific gravity, and a refractory material was attached to the outer periphery of the core material.

(Problem to be solved by the invention) Since the slag cut ball is a so-called disposable item, the steel material and refractory material in the conventional structure described above are quite expensive, and the manufacturing method is also required to improve the adhesion between the steel material and the refractory material. In addition, it is necessary to wrap a linear body around the outer circumference of the steel material to form a so-called anchor material, which poses the problem of requiring a considerable amount of effort.

In addition, in recent years, due to changes in converter melting technology, it has become necessary to shift from low specific gravity to high specific gravity for conventional slag cut balls, and for this reason, increasing the size of the core member for specific gravity adjustment, As a result, the refractory layer becomes thinner, which poses a problem in durability, and there is also a limit to the depth of the groove for flowing out the molten steel compared to conventional methods.

The present invention is made possible by adding a predetermined amount of binder to iron powder, dust, scrap iron and two grains of iron brick waste generated in the same converter factory that uses slag cut balls, and adjusting the specific gravity and circumference. The object of the present invention is to provide a slag-cut ball that provides a sufficient refractory layer.

Means for Solving the Problems> The above objects of the present invention can be achieved by employing the following means. In other words, the gist is that the outer surface of the core metal is coated with a refractory made by adding a predetermined amount of binder to iron powder, converter dust, scrap iron, and brick waste, and mixing with water to reduce the overall bulk specific gravity to 4. 0
In order to satisfy the fire corrosion resistance and high bulk specific gravity of the slag cut ball, the composition conditions for coating around the iron core were set such that the refractory content was 30 to 50% by weight and Metallic iron consisting of iron powder converter dust, scrap iron, granulated iron, etc.
It was set as 0% by weight. The slag cut ball and the outer surface of the core metal, iron powder, converter dust, scrap granulated iron,
Add a predetermined amount of binder to the brick scraps, cover with a refractory mixed with water, and further form a required number of grooves for molten steel outflow on the outer surface, and make the bulk specific gravity of the whole 4.0 to 5.5. This is a slug cut ball that is characterized by adjustments.

(Function) As shown in Figure 1 (a) and (b), the slag cut ball (1) floats in the middle of the molten steel in the converter a and the molten slag C, and the molten steel flows into the ladle d. The tapping port e is closed at the same time as the outflow of the slag is completed.Therefore, it is necessary that the slag cant ball (I) has a specific gravity intermediate between the volume gb and the molten slag C. , the present inventors have confirmed that it is optimal for the specific gravity to be in the range of 4.0 to 5.5.

On the other hand, converter dust, which is one of the mixed materials, is made by collecting dust such as dust generated in the furnace during the scouring process using a wet dust collection device, and contains a large amount of iron (Fe). ing. The converter dust recovered by primary separation of the dust-containing water contained in the above-mentioned dust using a screw conveyor, etc. is treated with a thickener, etc.
It is called coarse-grained dust because it has fewer fine particles, relatively large particle size, and stable particle size compared to subseparated dust. The T・Fe of this coarse powder converter dust is 8
Among them, M-Fe accounts for 90% or more, has a high bulk density (4th and 7th place), and has a stable particle size distribution.

In addition, iron powder, scrap iron granules, and brick scraps are generated from the converter factory, and these materials are kneaded with a binder such as cement with water and coated on the core metal to form any desired material. Form a slag cut ball with a bulk specific gravity of 4.
．． We succeeded in setting it in the range of 0 to 5.5.

In this way, on the outer surface of the core metal, iron powder, one piece of scrap iron, one piece of brick scrap,
The molded body obtained by adding a predetermined amount of various binders to a mixture of so-called industrial waste generated from a converter factory, such as converter dust, and kneading the mixture and coating it, has a high specific gravity. The core metal itself for adjusting the specific gravity can be made smaller than before, and it has therefore become possible to obtain a sufficient refractory coating thickness. As a result, it was possible to form the required number of molten steel outflow grooves on the outer surface of the slag cut, making it possible to outflow the molten steel and cut the slag in a short time.

For this reason as well, the refractory content should be 30 to 70% by weight; if the content of the refractory is less than 30%, the overall binding strength including metal iron will decrease, while if it is more than 70%, the bulk specific gravity will decrease. , initial goals cannot be achieved. Similarly, if the metallic iron content is less than 50%, bulk specific gravity cannot be satisfied, and conversely, if it is more than 70%, the loss resistance, crack resistance, etc. as a mixture with a refractory are greatly impaired.

<Example> Examples of the present invention will be described in detail below.

In this example, coarse-grained converter dust obtained by collecting dust generated in a 250-ton converter using a wet dust collection treatment device was used, and iron powder, scrap iron, and brick waste were collected from a converter factory. I used something.

Fig. 2 is a perspective view showing the shape of the core metal used in this example.
) A hanging odor (3) with a length of 580 m was attached to the upper end, and the total weight was 32.0 kg.

Next, Table 1 below shows the blending ratios of brick scraps, iron powder, dust, scrap iron and cement and bond as binders, and Table 2 below shows the blending weights.

Further, Table 3 below shows the component ratio and bulk specific gravity of three types of alumina-based brick waste.

Table 2: * indicates changes in materials and blending ratios. In this example, the brick scraps were manufactured by Kurosaki Ceramics Co., Ltd. under the trade name Zl! -816 was used.

30 to 50% of the refractories of the brick scraps, iron powder, and scrap iron.

Alumina Denka as a binder, Mo-, S4L, and silica flour were mixed with 70 to 50% of the mixture with coarse grain dust, and 6.8% of water was added to this mixture and kneaded for 4.0 minutes. As shown in Fig. 3, the core metal (2) was poured into a mold (4) with centrifugation, cured for 18 hours, heated at 230°C for 48 hours, removed from the frame, and then
Drying was carried out at 'C for 48 hours. As a result, as shown in FIG. 3, a hanging tool (3) and a slag cut ball (1) having grooves (5) for flowing out molten steel formed on the outer surface were able to be produced. The size of this slag cut ball (1) is 337 mm in outer diameter, and the shape of the molten steel outflow groove (5) is 38 mm in width.
The depth was 30 mm, the number of fibers was 5 vertically and 1 horizontally, and the specific gravity was 5.0.

The slag cut balls obtained in this way were placed on the iron plate.
The surface damage rate of the slag cut ball was measured by allowing it to fall naturally from a height of 0 m. Although it has been confirmed from past experience that the surface damage rate should be 10% or less, the slag cut balls of this example were all about 7 to 8%.

Also, the slag cut ball according to this example was heated to 1650°C.
As a result of investigating the buoyancy and heat resistance by placing it in molten steel, it was found that approximately 7
It has been confirmed that it retains its original shape for a minute and is sufficiently durable for practical use. As a result, the original shape can be easily maintained until the steel is tapped.
A reliable slag cut ball was made in a short time.

In addition, by using alumina-based brick scraps, the bonds between coarse dust, powdered iron, and scrap iron are covered with the refractory material of the brick scraps, and the bonds between each particle are strengthened. It has become possible to improve durability.

Furthermore, for comparison, the results of the conventional example in which the outer surface of the core metal was coated with a castable refractory and this example are shown in Table 4 below.

Table 3 Note that Δ is in the range of 50 to 70 χO is in the range of 70 to 100 However, by coating the outer surface of the metal core with a refractory mixed with a binder, it was possible to achieve the required specific gravity and coating layer thickness. As a result, the manufacturing cost of slag cut balls is approximately 70% lower than that using conventional castable refractories.
%, making it possible to significantly reduce costs.

<Effects of the Invention> As described above, although the present invention produces coarse converter dust in large quantities, in order to make effective use of it, it is necessary to undergo considerably complicated processing. and two iron powder particles generated from the converter factory.

By arbitrarily mixing scrap iron and brick scraps, a refractory layer with high mechanical strength is formed, and the specific gravity can be adjusted arbitrarily by changing the mixing ratio, so it can be applied to slag cutting of all steel types. In addition, when cutting slag, there are various effects such as less remaining hot water, improved success rate, and lower costs.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are explanatory diagrams showing the state of use of the present invention, Figure 2 is a perspective view showing the shape of the core metal used in the present invention, and Figure 3 is a means for manufacturing a slag cut ball. FIG. 4 is a cross-sectional view showing an example of the slag cut ball according to the present invention. In the figure: (1) Varnish slug cut ball (2); Core metal (4): Formwork (5): ? Steel drain groove

Claims (1)

[Scope of Claims] 1. The outer surface of the core metal is coated with a refractory made by adding a predetermined amount of a binder to iron powder, converter dust, scrap iron, granulated iron, and brick scraps and mixing with water; The blending amount is 30 to 50% by weight, and the metal iron is 70 to 50% by weight, and the bulk specific gravity of the whole is 4.0 to 5.
A slug cut ball characterized by being adjusted to 5. 2. Cover the outer surface of the core with a refractory made by adding a predetermined amount of binder to iron powder, converter dust, scrap iron, granulated iron, and brick waste and mixing with water, and then form a groove on the outer surface for molten steel to flow out. A slag cut ball characterized by having a required number of slag cut balls formed therein and having an overall bulk specific gravity adjusted to 4.0 to 5.5.