JPS6011274A - Fine castable refractories - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dense castable refractory having excellent corrosion resistance and strength.

Among conventional castable refractories, those that use refractory aggregate toalumina cement, or those that are further blended with clay, ultrafine refractory powder, etc., have improved strength by reducing the amount of water added during kneading. Peptizers, water reducers, etc. are often added in order to improve the fluidity of the kneaded material and improve workability. Deflocculants, water reducers, and the like have air entrainment effects due to their surface active effects. If a small amount of air is entrained, the fluidity will be improved due to the bearing effect, but if a deflocculant, water reducer, etc. are added, excessive air entrainment will occur. In other words, in this case, a large amount of air bubbles are generated when the wires are crossed, which not only worsens the fluidity and reduces workability, but also causes the strength of the castable refractory construction to become significantly lower due to the high porosity. The major drawback is that it decreases. Such drawbacks may also occur when the refractory material is selected by flotation or the like, because the surfactant used at that time remains attached to the refractory material.

As a result of intensive research to overcome the above-mentioned drawbacks, the present inventor found that when an antifoaming agent is added to conventional castable refractory materials together with a deflocculant, in addition to the water-reducing effect of the deflocculant, the antifoaming agent is By adding it, it is possible to suppress or eliminate bubbles during crosstalk, reduce the porosity of the construction body, significantly improve strength and corrosion resistance, and improve workability due to good fluidity. The present invention was completed based on these findings. That is, in the present invention, a peptizer is added to 100 parts by weight of a castable refractory material using refractory aggregate and alumina cement, or a castable refractory material that is further blended with refractory ultrafine powder or (and) clay. , o-o, a parts by weight and antifoaming agent from 0.01 to 1.0
Pertains to dense castable refractories added in parts by weight.

The refractory aggregate used in the present invention includes, for example, high alumina raw materials such as fused alumina, sintered alumina, bauxite, clay shale, and synthetic mullite, acidic raw materials such as clayey chamotte, zircon, waxite, and kyanite, and magnesia. basic raw materials such as carbon, silicon carbide, etc.
At least one of these is used. The refractory aggregate is used by adjusting the particle size appropriately as usual so that it can be packed densely.

Just to be sure, to give you an example, you can use 80
-50% by weight, about 10-50% by weight for those with a diameter of 1 mm - 0.074 mm, and about 20-40% by weight for those with a diameter of about 0.074 mm or less.

As the alumina cement, for example, super alumina cement, No. 1 cement, No. 2 cement, etc. can be used.

The refractory ultrafine powder has an average particle size of about 25 μm or less, preferably 1 μm or less, such as high alumina ultrafine powder such as sintered alumina or calcined alumina, zircon ultrafine powder, silica ultrafine powder, and the like. As the clay, for example, kaolin, Honbushi clay, Frogme clay, etc. can be used.

Examples of the deflocculant in the present invention include sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate,
Phosphates such as sodium tetrapolyphosphate, sodium silicate 1
No. 8, silicates such as sodium silicate No. 8, lignin sulfonates such as sodium lignin sulfonate and calcium lignin sulfonate, carbonates such as sodium carbonate, sodium bicarbonate, and lithium carbonate, sodium acrylate, and polyacrylic acid. Examples include acrylates such as soda, and at least Ha is used. The amount of deflocculant used is 1 in total for refractory aggregate, alumina cement, refractory ultrafine powder, clay, etc.
0.00 parts by weight. The amount is about 2.8 parts by weight of O2N. If it is less than 0.01 part by weight, the water reduction effect will not be sufficient, and O,
If it exceeds a part by weight, it is not preferable because it shows a tendency to agglomerate and the fluidity decreases.

Examples of antifoaming agents in the present invention include alcohols such as octyl alcohol and polyalkylene glycol, fatty acid esters such as ethylene glycol distearate, sorbitan oleate, and rubitan trioleate, amines such as cyamylamine, di- Ethers such as t-amylphenoxyethanol, phosphate esters such as tributyl phosphate and trioctyl phosphate, metal soaps such as aluminum stearate and potassium oleate, silicone oil, silicone oil compound, emulsion of silicone oil compound, etc. A number of silicones can be used, and at least one of them is used. The antifoaming agent mentioned above may be liquid, solid, or semisolid, and any form of the antifoaming agent can be used. The defoaming action includes a foam-breaking action and a foam-inhibiting action, and all of the above-mentioned defoaming agents have a foam-breaking action and a foam-inhibiting action.

The amount of antifoaming agent used is 0.01 to 100N parts in total of fireproof aggregate, alumina cement, fireproof ultrafine powder, clay, etc.
It is about 1.0 part by weight. If it is less than 0.01 part by weight, the defoaming effect will not be sufficient, and if it exceeds 1.0 part by weight, the fluidity may decrease or the hardening of the alumina cement may be inhibited, which is not preferable.

The dense castable refractory of the present invention can reduce the porosity of the constructed body, in other words, can make the constructed body dense, especially by using an antifoaming agent, and not only has excellent strength and corrosion resistance, but also has excellent fluidity. Due to its good properties, workability has been significantly improved. Therefore, for example, a furnace skid pipe,
Can be used suitably for tandish covers, silk covers, etc.
High durability can be obtained.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Examples 1 to 8 and Comparative Examples 1 to 8 Using dense castable refractories of the present invention and comparative castable refractories (same as those of the present invention except that no antifoaming agent was used) having the formulations shown in Table 1. , conducted the following tests.

O Apparent porosity, bulk specific gravity, compressive strength and bending strength (at room temperature, hot): Knead the blends in Table 1 and form 40X40X16
It was cast into an Omm mold.

After curing, the mold was demolded and dried at 110°C for 20 hours.

After drying, the test pieces were fired at 900°C, 1800°C, or 1500''C for 8 hours, respectively.

In addition, the hot bending test was conducted at 1200°C or 1400°C using a sample that had been dried at 110°C for 20 hours.

・Slag test (crucible method) Diameter across sides 50mm, height 50mm
It was cast into a crucible shape with a hole of 18 mm in diameter and 800 mm deep in the center of the upper surface. After curing and drying, 15 g of mill scale was put into the hole and fired at 1450° C. for 8 hours in a propane-oxygen furnace. After cooling, cut the center of the crucible and measure the total area of the eroded and permeated areas (cm2).
) was measured.

The results of each test are shown in Tables 2 and 8. Note that each test other than the slag test was conducted twice, and the average value is shown.

As is clear from Tables 2 and 8, in all items, the examples exhibited higher density and strength than the comparative examples, and were also superior in corrosion resistance.

(that's all)

Claims (1)

[Claims] 1. Add 0.01 to 0.01 parts by weight of a deflocculant to 100 parts by weight of a castable refractory material using refractory aggregate and alumina cement, or a castable refractory material further blended with refractory ultrafine powder or (and) clay. A dense castable refractory to which 0.8 parts by weight and 0.01 to 1.0 parts by weight of an antifoaming agent are added.