JP2009298633A - Casting monolithic refractory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a casting monolithic refractory having excellent constructability in a job site. <P>SOLUTION: The casting monolithic refractory contains 0.1-10 pts.wt. binder as the addition ratio to 100 pts.wt. fireproof aggregate. The binder is prepared by adding 0.05-30 pts.wt. zinc oxide into 100 pts.wt. mixture obtained by mixing sodium silicate with alkali metal phosphate in a ratio of (6:4)-(2:8). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cast amorphous refractory.

  In the furnace main body, the ladle, the ladle, etc., since it is in contact with various high-temperature melts or exposed to a high-temperature atmosphere, it has been conventionally performed to line with a cast amorphous refractory. Alumina cement is generally used as an amorphous refractory. However, since it hardens in a short time after kneading, bring a mixer etc. to the construction site and add water little by little to prevent the installer from hardening. It is necessary to perform kneading, and there are problems in terms of work and cost.

For this reason, in Patent Document 1, powdered silicate and alkali metal phosphate are mixed at a predetermined mixing ratio, added to a refractory aggregate at a predetermined ratio, and then added with water and kneaded. A thermosetting cast refractory is disclosed. Since this cast refractory is hard to cure at room temperature, it can be kneaded in advance in a factory and then transported to the work site.
Japanese Patent Laid-Open No. 10-130065

  However, the thermosetting cast refractory disclosed in Patent Document 1 may cause a separation phenomenon that the aggregate in the material sinks and the water floats during long-term storage or transportation by truck, There was room for further improvement in terms of workability.

  Then, an object of this invention is to provide the casting unshaped refractory excellent in the construction property on the spot.

  As a result of diligent research, the present inventors have further added zinc oxide as a binder in a cast amorphous refractory in which a binder containing sodium silicate and an alkali metal phosphate is added to a refractory aggregate. Even after curing once after the hydro-kneading, it was found that the fluidity was developed again by applying vibration, and the present invention was completed.

  That is, the object of the present invention is that the binder is added in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the refractory aggregate, and the binder includes sodium silicate and alkali metal phosphate in a weight ratio. This is achieved by a cast amorphous refractory characterized by adding 0.05 to 30 parts by weight of zinc oxide to 100 parts by weight of the mixture mixed at a ratio of 6: 4 to 2: 8.

  According to the present invention, it is possible to provide a cast amorphous refractory having excellent workability on site.

  The cast amorphous refractory of the present invention is produced by adding a binder to a refractory aggregate.

(A) Refractory Aggregate The refractory aggregate used in the present invention includes (1) high alumina raw materials such as fused alumina, sintered alumina, and calcined alumina (2) calcined bauxite, mullite, sillimanite, kyanite Alumina-silica raw materials such as andalusite (3) Silica-alumina raw materials such as rholite, chamotte and clay minerals (4) Silicic raw materials such as silica sand, silica and fused silica (5) Chromium iron ore, sintered spinel, Spinel raw materials such as fused spinel (6) Basic raw materials such as magnesia clinker, forsterite, dolomite clinker, calcia (7) Zircon material (8) Zirconia material (9) Silicon carbide, zirconium carbide, aluminum carbide, carbonized Boron and other carbide materials (10) Silicon nitride, zirconium nitride, boron nitride, aluminum nitride and other nitride materials (11) Coke, natural graphite, Concrete graphite, anthracite, carbon black, carbon brick scrap, carbonaceous feedstock (12) sodium silicate mass, such as an electrode scrap, silicon can be used for refractory powder such as chromium oxide. Further, as the refractory aggregate, one or more types can be selected and used from each of these groups, or one or more types can be selected and used from different groups. The refractory aggregate is preferably adjusted in particle size to about 5 mm or less.

(B) Binder As the binder, a mixture obtained by adding zinc oxide to a mixture containing hardly soluble powdered sodium silicate and alkali metal phosphate is used.

It is preferable to use a powdered sodium silicate containing 50 to 80% SiO ₂ and 15 to 40% Na ₂ O. The molar ratio of SiO ₂ and Na ₂ O is not particularly limited. However, if the solubility is too small, it is difficult to cure, whereas if the solubility is too large, the composition is cured quickly and it is difficult to ensure the fluidity during construction. Therefore, it is preferable to adjust appropriately so that the solubility at 20 ° C. is about 0.1 to 5%.

Examples of the alkali metal phosphate include sodium phosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, potassium phosphate, and potassium polyphosphate. In particular, hydrate of aluminum dihydrogen tripolyphosphate (AlH _{2 P 3 O 10 · 2H 2} O) can be preferably used.

  Zinc oxide (ZnO) is preferably in the form of fine powder, and is uniformly dispersed in a mixture of sodium silicate and alkali metal phosphate. Moreover, it is preferable that the purity of the zinc oxide to be used is 90% or more.

(C) Mixing ratio i) Binder (sodium silicate, alkali metal phosphate, zinc oxide)
As for the mixing ratio of sodium silicate and alkali metal phosphate contained in the binder, if the proportion of alkali metal phosphate is too large, it is difficult to cure after construction and sufficient strength cannot be obtained, while the proportion of sodium silicate is large. When too much, fluidity | liquidity will deteriorate, and it will become hard to produce early, and it will become the tendency for construction to become difficult. Therefore, it is preferable to mix sodium silicate and alkali metal phosphate in a weight ratio of 6: 4 to 2: 8, and more preferably in a ratio of 4: 6 to 2.5: 7.5. preferable. Moreover, the dispersion | distribution of the particle size distribution, powder bulk, etc. of powders, such as a refractory aggregate which comprises a slurry, will also have dispersion | variation also in the property of the slurry after hydromixing, and may have a bad influence on workability | operativity. From the viewpoint of being hardly affected by such variations in raw material powder, the most practically preferred weight ratio of sodium silicate and alkali metal phosphate is 1: about 2.8.

  In addition, if too much zinc oxide is added to the above mixture, it will be difficult to develop fluidity again even if vibration is applied, while if too little, the generated separation-type refractory material will have the same separation phenomenon as before. May occur. Therefore, it is preferable to add 0.05-30 weight part of zinc oxide with respect to 100 weight part of the said mixture, and it is more preferable to add 1-25 weight part.

ii) Refractory aggregate and binder If the ratio of the binder to the refractory aggregate is too small, sufficient strength cannot be obtained after construction, while if too large, sufficient corrosion resistance cannot be obtained after construction. Therefore, it is preferable that the addition ratio of the binder is 0.1 to 10 parts by weight with respect to 100 parts by weight of the refractory aggregate.

iii) Others The cast amorphous refractories of the present invention may be added to those used for conventional cast amorphous refractories as long as the effects of the present invention are not impaired. For example, dispersants such as alkali metal carboxylates, polycarboxylic acid polymers, and alkyl sulfonates can be used.

(D) Method of use The above-mentioned cast amorphous refractory powder is naturally cured in about 1 to 3 days by adding an appropriate amount of water and kneading in advance at a factory or the like. Thereby, the separation phenomenon of water during storage or transportation can be prevented. The amount of water added to the cast amorphous refractory can be, for example, 5 to 7 parts by weight with respect to 100 parts by weight of the cast amorphous refractory powder.

  Next, the cast amorphous refractory cured after the hydro-kneading is transported to the site, and vibration is applied with a vibrator or the like immediately before construction. In the cast amorphous refractory according to the present invention, since an appropriate amount of zinc oxide is added to the binder, fluidity can be easily expressed by applying vibration, and casting can be performed.

  After the pouring work is completed, the surface of the cast amorphous refractory is heated with a burner or the like. The heating conditions are, for example, about 80 to 100 ° C. and about 3 to 5 hours. By such forced heating, the poorly soluble powdered sodium silicate has increased solubility and reacts with the alkali metal phosphate. As a result, the poured cast refractory thus constructed is cured to such an extent that it can sufficiently function as a refractory material.

  Thus, according to the cast amorphous refractory of the present invention, water separation can be suppressed by a pseudo-cured state during storage and transportation, and fluidity can be easily expressed by applying vibration during construction. Therefore, workability can be improved.

  The cast amorphous refractories of the present invention are blast furnaces for melting or treating various metals, glass, cement, slag, industrial waste, etc., melting / holding furnaces for various non-ferrous metals such as cupola, aluminum, copper, etc. Soaking furnace, heating furnace, grooved or crucible type electric induction heating furnace, various incinerators, cement kiln, glass melting furnace, etc. It can be suitably used for the purpose of pouring and curing in a device such as a duct or a boiler, which is used at a high temperature, so as to come into contact with various high-temperature melts or to cover a portion exposed to a high-temperature atmosphere.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention. However, the present invention is not limited to the following examples.

  As a cast amorphous refractory, using a weight mixing ratio of sodium silicate and alkali metal phosphate as a parameter, a mixture of each material in the weight ratio shown in Table 1, using water kneading, the flow value immediately after kneading While measuring, this kneaded material was stored for a long time, and the flow values after 7 days, 14 days, 21 days, and 28 days were measured. The flow value was measured according to JIS R2521 (alumina cement flow test), and vibration was applied by a vibrator immediately before the measurement in order to develop fluidity.

  As shown in Table 1, in Comparative Example 1 and Examples 1 to 4, the flow value (ie, fluidity) gradually decreases as the proportion of sodium silicate with respect to the alkali metal phosphate increases. However, in Example 4, the flow value after 28 days was 120 or more, and good fluidity could be expressed by applying vibration even after long-term storage. On the other hand, for Comparative Example 2, the proportion of sodium silicate became too large, and the fluidity decreased sharply when the storage period was prolonged, and for Comparative Example 3, the proportion of sodium silicate was further increased. After the day, even if vibration was applied, fluidity did not appear and construction was impossible.

  During storage of the kneaded product, whether or not water was separated from the refractory raw material was regularly checked visually, but no separation phenomenon occurred in any of Examples 1-4 and Comparative Examples 1-3. .

  After 28 days from the start of storage of the kneaded product, the kneaded product was vibrated with a vibrator to develop fluidity, poured into a 40 × 40 × 160 (mm) mold, cured at 60 ° C. for 3 hours, and then removed. Frameability was evaluated for workability (fluidity and shape retention).

  As shown in Table 1, in Examples 2 to 3, sufficient fluidity during construction was secured, and after construction, sufficient shape retention was maintained, and the workability was good. It was. Moreover, although the shape retention property of Example 1 was slightly lowered and the fluidity of Example 4 was slightly lowered, construction work was possible in all cases. On the other hand, in Comparative Example 1, sufficient curing strength after construction was not obtained, and it was difficult to remove the frame. In Comparative Example 2, the fluidity during the construction was not sufficient, and it was difficult to fill the mold. Comparative Example 3 was cured during storage as described above, and construction work was impossible.

次に、珪酸ナトリウム及びアルカリ金属リン酸塩の混合物に対する酸化亜鉛の重量混合比をパラメータとして、表１の場合と同様に、フロー値の測定、分離現象の目視、及び施工性の評価を行った。

Next, using the weight mixing ratio of zinc oxide to the mixture of sodium silicate and alkali metal phosphate as a parameter, the flow value was measured, the separation phenomenon was visually observed, and the workability was evaluated in the same manner as in Table 1. .

  As shown in Table 2, for Comparative Example 4 and Examples 5 to 9, the flow value (ie, fluidity) gradually decreased as the proportion of zinc oxide increased, but also in Example 9, The flow value after 28 days secured 120 or more, and even after long-term storage, good fluidity could be expressed by applying vibration. On the other hand, in Comparative Example 5, since the ratio of zinc oxide became too large, fluidity was not expressed even after vibration was applied after 21 days, and the construction became impossible.

  During the storage of the kneaded material, no separation phenomenon occurred in Examples 6 to 9 and Comparative Example 5. In Example 5, although some water floating occurred, construction work was possible. On the other hand, in Comparative Example 4, the water separation phenomenon was likely to occur, and the construction work could not be performed without sufficient stirring.

  Regarding workability, Examples 5 to 8 ensured sufficient fluidity during construction, cured after construction, maintained sufficient shape retention, and had good workability. In Example 9, although the fluidity was slightly lowered, construction work was possible. On the other hand, in Comparative Example 4, since the water separation phenomenon occurs as described above, workability is ensured if sufficient stirring is performed, but complicated stirring work using a mixer or the like is necessary. Moreover, the comparative example 5 hardened | cured during storage as mentioned above, and construction work was impossible.

Claims (1)

The addition ratio of the binder to 100 parts by weight of the refractory aggregate is 0.1 to 10 parts by weight,
In the binder, 0.05 to 30 parts by weight of zinc oxide is added to 100 parts by weight of a mixture in which sodium silicate and alkali metal phosphate are mixed at a weight ratio of 6: 4 to 2: 8. A pour-shaped amorphous refractory.