JPS63174758A - Slag adsorbent - Google Patents

Abstract

PURPOSE:To obtain a slag adsorbent which has excellent slag removability and property to retain the heat of a molten metal and permits easy recovery and removal by allowing glass fibers having an SiO2 content of a specific value or above to exist mixedly in the surface part of a calcined body formed by molding refractory material powder to a plate shape and calcining the molding. CONSTITUTION:Mixed slurry 1 composed of agalmatolite powder, the glass fibers contg. >= 75wt.% SiO2 and water is poured into a molding tool 2 consisting of a metal flask 3, a bottom plate 4 and a press plate 5. The compression molding of the mixed slurry 1 pressurized and molded in the tool 2 is then calcined to obtain the slag adsorbent having the desired glass fibers existing mixedly in at least the surface part of the calcined body. The slag adsorbent which has the excellent slag removability and property to retain the temp. of the molten metal and permits the easy recovery and removal from the molten metal is thereby realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a slag removal means that can easily remove slag floating in molten cast iron.

(Prior art) Usually, cast iron is melted in a melting furnace such as a cupola or a low-frequency furnace, and if a drop in casting temperature is not desired, the molten cast iron is transferred to a holding furnace and kept at a high temperature. is maintained.

When pouring into the mold, the metal is transferred from the melting furnace or holding furnace to a tapping ladle and a pouring ladle, and finally poured into the pouring ladle or three molds.

At this time, in order to prevent the slag in or on the surface of the molten metal from being poured into the mold together with the molten metal, measures are taken to remove the slag present together with the molten metal mainly in the pouring ladle.

Such measures include scattering natural pumice particles on the surface of the molten metal, or floating asbestos plates on the molten metal so that the slag is adsorbed onto these objects, and then collected and removed.

(Problems to be Solved by the Invention) However, although natural pumice grains have an excellent slag adsorption effect, it is difficult to completely remove the pumice grains from the molten metal after adsorbing the slag, and the molten metal heat retention effect cannot be expected.

On the other hand, although asbestos boards have good slag adsorption and heat retention effects, they pose problems in terms of occupational safety and health. Furthermore, when asbestos plates are recovered after slag adsorption, they tend to crack and break into small pieces, making recovery time-consuming and difficult to completely remove asbestos pieces from the molten metal.

The present invention was made in view of such problems, and an object thereof is to provide a slag removal means that has excellent slag removal effects and molten metal heat retention effects, is easy to collect and remove, and is free from problems in terms of occupational safety and health.

(Means for Solving the Problems) The slag removal means of the present invention taken to achieve the above object is such that the 5i02 content is reduced in at least the surface layer of a fired body in which refractory material powder is molded and fired into a plate shape. The structure is such that 75% by weight or more of glass fiber is mixed therein.

(Example) The slag adsorbent of the present invention has glass fibers having a 5i02 content of 75% by weight or more mixed in at least the surface layer of a fired body in which waxite powder as a refractory material powder is molded and fired into a plate shape. The adsorbent is used with the glass fiber mixed side floating on molten metal.

The reason why waxite powder is preferable as a refractory material powder mixed with glass fiber is that waxite powder has a content of 5t02 by weight in its composition.
50-60%, Aj'2 (h 50-40%,
This is because it is resistant to thermal shock, and its fired body is less likely to crack even when rapidly heated from room temperature to molten metal temperature. In addition, it is inexpensive and has excellent economic efficiency. Note that waxite is known as a raw material for firebrick used for lining ladle and the like.

Glass fibers are mixed in at least the surface layer of the fired body of the waxite powder. Glass fiber is mixed because it has excellent slag adsorption properties, but the amount mixed in is 2% by weight.
~8% is appropriate. This is because if it is less than 2%, the slag adsorption properties will be poor, while if it exceeds 8%, the fibers will fall off significantly.

The glass fiber has a 5tOz content of 75% by weight.
The above are used. This is because the fibers containing 75% by weight Miura have poor heat resistance to molten cast iron, and the fibers themselves turn into slag.

In order to increase the SiO2 content in the glass fibers, the glass fibers are usually subjected to acid treatment.

Acidic treatment involves immersing glass fibers with low 5iQ2 content in an acidic solution to remove impurities such as Cab and Mgo in the fibers.
, Fe2O3+ Cr2O3+ Na2O2,K2
O1Ti02. This process lowers the content of B2O3 and the like and increases the 5iQ2 content as a result.

Glass fibers are usually used with a wire diameter of 3 to 9 μm, and the length is determined from the viewpoint of ease of mixing with waxite powder.
．． It is best to cut it into pieces of about 5 to 3 mm.

As shown in FIG. 1, the adsorbent of the present invention has a
A mixed slurry 1 of 0 mesh of waxite powder, the required glass fiber, and water is poured into a mold 2, and pressure molding is performed to remove water and improve the packing density, and the resulting compression molded body is fired. It was formed by In the figure, the mold 2 is composed of a metal punching frame 3, a bottom plate 4 and a presser plate 5 fitted to the metal frame 3, and the mixed slurry 1 is pressurized through the presser plate 5. be done.

When the compression molded body is fired, the clay content in the wax stone material acts as a binder, and the particles of the wax stone powder bond together.
Sufficient strength for handling is ensured.

Incidentally, the firing temperature is set below the cristobalite transformation point at which a brittle structure occurs, and is usually carried out at 800 to 1000°C, and the firing temperature may be about 3 to 6 hours. Although the glass fibers in the molded body are also fired and shrunk by this firing, the heat resistance and slag adsorption properties of the glass fibers are not affected.

Since the adsorbent of the present invention has excellent heat resistance and heat insulation properties, that is, heat retention effect, it can of course be used not only for pouring ladle but also for molten metal in tapping ladle, melting furnace, and holding furnace.

Furthermore, since it has sufficient strength through firing, it is easy to handle, and it is easy to recover and remove it from the molten metal.

Next, specific examples will be listed and explained.

<Example 1> (1) 500 g of the following waxite powder, 20 glass fibers
g and 82.5 cc of water were kneaded to prepare a mixed slurry.

○Main components of waxite powder: 5iOz 60%, A172Ch 40% grains
Degree: 300 mesh O Glass fiber 5i02 Content: 98% Size: φ9μ lock x length 0.5~3 fins (2) Pour the mixed slurry into the mold and pressurize with a surface pressure of 200kg/-, 200X200X Thickness 51 A heavy compression molded body was obtained.

After naturally drying this for 24 hours, it was heated at 1000℃ x 6 hours.
Fired.

(3) When the adsorbent obtained by firing was floated on molten cast iron at 1500° C. for 7 minutes, no cranking occurred and the slag adsorption area ratio was 60 to 80%.

Note that the slag adsorption area ratio (%) refers to the slag adsorption area xlOO/adsorbent surface area on the molten metal side surface of the adsorbent.

(4) For comparison, a fired body of waxite powder that does not contain glass fibers was produced under the same conditions as in (2) above, and the slag adsorption area ratio was measured to be 10 to 30%.

<Example 2> (11 Same as Example 1) 500 g of dolomite powder and 82.5 g of water
cc and kneaded to prepare a waxite powder slurry.

(2) 20 g of the same glass powder as in Example 1 was kneaded with 250 g of the waxite powder slurry to obtain a mixed slurry, which was poured into a mold, and the remainder of the waxite powder slurry was poured onto it.

Then, it was pressure-molded under the same conditions as in Example 1 and then fired.

(3) The slag adsorption rate of the obtained adsorbent was examined by floating it on a 1500° C. molten metal with the glass powder mixed side as the molten metal side, and it was found to be 80 to 90%.

In this case, although the same amount of raw materials as in Example 1 was used, the slag adsorption rate was improved because the amount of glass fiber mixed on the slag adsorption side was twice as large. In this example, the layer without glass fibers serves as a back-up layer.

(Effect of the invention) As explained above, the slag adsorbent of the present invention has a specific 5i
Since the glass fiber of 02 composition is mixed with the refractory material powder and molded and fired into a plate shape, it has excellent slag adsorption and heat insulation properties, and has good high temperature strength, so it is easy to recover and remove from F4 hot water. It is safe from an occupational health perspective, and has great utility in the foundry industry.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a mold showing the state of molding the slag adsorbent of the present invention. Patent applicant: Kubota Iron Works Co., Ltd. Figure 7

Claims (1)

[Claims] (1) A slag adsorbent characterized in that glass fibers with an SiO_2 content of 75% by weight or more are mixed in at least the surface layer of a fired body obtained by molding and firing refractory material powder into a plate shape.