KR20050064542A - Batch composition of forming refractories for blast furnace tap hole - Google Patents

Abstract

The present invention relates to a high strength blast furnace outlet molding material refractory composition, more specifically 48 to 60% by weight of sintered alumina, 10 to 13% by weight of silicon carbide, 6 to 9% by weight of silicon nitride, 6 to 10% by weight of calcined alumina, Provided is a blast furnace outlet molding material refractory composition comprising 5 to 8% by weight of ceramic fiber, 2 to 4% by weight of metal Al powder, and 4 to 7% by weight of alumina cement. Blast furnace outlet molding material refractory composition according to the present invention is excellent in thermal shock resistance and corrosion resistance.

Description

Blast Composition of Forming Refractories for Blast Furnace Tap Hole}

The present invention relates to a refractory constituting the outer portion of the exit port is chartered through the exit port in the blast furnace. More specifically, the present invention relates to a high-strength blast furnace outlet molding material refractory composition excellent in thermal shock resistance and erosion resistance.

In general, the molding material constituting the outer portion of the blast furnace tap opening is eroded by the scattering of the molten iron and the reaction with the molten iron under high heat at the time of departure, and is used in a harsh atmosphere subjected to thermal shock by cooling when the starting line is finished. The construction method was also hit by an air rammer in the prior art, but the long time work in a poor working environment with high heat and dust causes inconvenience to the worker. Refractories with good corrosion resistance are required to shorten the construction time and to reduce the number of repairs.

Representative examples of the prior art having similar contents to the molded material refractory materials include Japanese Patent Laid-Open Nos. 1999-292643 and 1999-116345.

Japanese Laid-Open Patent Publication No. 1999-292643 relates to an amorphous refractory material having excellent heat resistance, characterized in that it contains a refractory raw material, a binder and a compound powder having poor water solubility and sublimation property at 100 ° C. or lower. Japanese Laid-Open Patent Publication No. 1999-116345 discloses an alumina cement and a carboxyl group-containing polyether dispersant in 100 parts by weight of a fire-resistant aggregate containing 1 to 20% by weight of ultrafine alumina and / or Al ₂ O _{3 ·} MgO based fine powder. The present invention relates to an amorphous refractory for inflow construction by addition.

All of them are limited in use because of their high expansion and low strength to solve all problems such as heat deficiency and deterioration due to prolonged use, which can be regarded as drawbacks of castable refractory.

Accordingly, the present inventors have repeatedly conducted research and experiments to solve the above problems to complete the blast furnace outlet molding material refractory composition.

In order to solve the problems as described above, the present invention is made of alumina and silicon carbide, which are resistant to erosion, aggregates, and fine pores are formed by adding ceramic fibers and a small amount of metal powder to increase thermal shock resistance, ultrafine raw materials and oxidation. It is an object of the present invention to provide a high-strength tap molding material refractory material having high high temperature strength, in which chromium is added to make the bonding part sinterable, thereby increasing the bonding strength.

The above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention is sintered alumina 48-60% by weight, silicon carbide 10-13% by weight, silicon nitride 6-9% by weight, calcined alumina 6-10% by weight, ceramic fiber 5-8% by weight, metal The blast furnace outlet molding material refractory composition containing 2-4 weight% of Al powder and 4-7 weight% of alumina cement is provided.

The alumina content of the ceramic fiber (fiber) is in the range of 30 to 60% by weight, the length of the fiber may be 1 to 5mm.

Hereinafter, the present invention will be described in detail.

In the blast furnace outlet molding material refractory composition, 48 to 60 wt% of sintered alumina, 10 to 13 wt% of silicon carbide, 6 to 9 wt% of silicon nitride, 6 to 10 wt% of calcined alumina, and 5 to 8 wt% of ceramic fiber %, 2 to 4 weight% of metal Al powder, and 4 to 7 weight% of alumina cement.

The alumina has a high purity and excellent sintering and corrosion resistance to act as an aggregate in the molded material refractory material. When the amount of sintered alumina used was less than 48% by weight, the refractory degree of refractory was low and erosion was severe, which was not suitable for use. Therefore, a suitable amount of sintered alumina is 48 to 60% by weight.

Since silicon carbide (SiC) has excellent corrosion resistance to molten iron, as in alumina, it serves as an aggregate in a molded material refractory material. When the amount of silicon carbide used was less than 10% by weight, the effect of improving corrosion resistance was small, and when the amount used was 13% by weight or more, the amount of silicon carbide was used, resulting in poor sintering resistance and deterioration in corrosion resistance and strength. Therefore, a suitable amount of silicon carbide is 10 to 13% by weight.

The silicon nitride (Si3N4), like silicon carbide, serves to enhance corrosion resistance to molten iron and to strengthen the bonding strength of the refractory bonding portion at high temperatures. When the amount of silicon nitride used was less than 6% by weight, the amount of use was small, so that the effect of improving corrosion resistance was small, and when the amount used was more than 9% by weight, the amount of used was large, resulting in poor sintering property, which was unsuitable. Therefore, a suitable amount of silicon nitride is 6 to 9% by weight.

Since the calcined alumina is active as an ultra fine powder, it serves to improve the sinterability of the refractory to increase the high temperature strength. If the amount of calcined alumina is less than 6% by weight, the amount of sintering was lowered due to insufficient amount of use. If the amount of the calcined alumina was more than 10% by weight, the shrinkage was severe. Therefore, a suitable amount of calcined alumina is 6 to 10% by weight.

The chromium oxide (Cr 2 O 3) serves to enhance the strength at high temperatures of the molding material refractory material. Chromium oxide is added in the form of natural chromium ore.If the amount is less than 7% by weight, the effect of increasing strength at high temperatures is small, and if the amount is more than 10% by weight, erosion is severe due to impurities such as iron oxide contained in the chromium ore. It was. Therefore, a suitable amount of chromium oxide is 7 to 10% by weight.

The ceramic fiber (ceramic fiber) serves to suppress the thermal reaction that is likely to occur during drying by forming micropores in the molding material refractory material. There are various kinds of ceramic fibers depending on the components, but in the present invention, the alumina content is in the range of 30 to 60 wt% and the fiber length is 1 to 5 mm. If the fiber length is less than 1mm is too fine to increase the toughness, at 5mm or more, the fibers are entangled and do not loosen well, so kneading is not good. If the alumina content of the fiber is less than 30% by weight, the heat resistance temperature of the fiber is low, which makes it unsuitable for use at high temperatures. At 60% by weight or more, the alumina content is excessively poor, and the adhesion is not good with the alumina, which is the main material surrounding the fiber. The amount of ceramic fiber used was less than 5% by weight because the amount of fiber was small, which did not help to form micropores. The erosion was lowered and unsuitable. Therefore, a suitable amount of ceramic fiber is 5 to 8% by weight.

The metal aluminum (Al) serves to form micropores by foaming while generating hydrogen gas by reacting with moisture in the molding material refractory material. When the amount of metal aluminum used is 2% by weight or less, the effect of forming micropores is small, and when the amount used is 4% by weight or more, the amount of porosity and pore diameter generated is large, so that erosion is severe and the strength is lowered. Therefore, a suitable amount of metal aluminum is 2 to 4% by weight.

The alumina cement serves to increase the plastic strength at room temperature strength and 1200 ℃ or more of the refractory. If the amount of alumina cement used is less than 4% by weight, the amount is insufficient and the effect of strength increase is small. If the amount used is more than 7% by weight, the room temperature strength is large, but the erosion is severe. Therefore, a suitable amount of alumina cement is 4 to 7% by weight.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples.

[Examples 1 to 5] and [Comparative Examples 1 to 4]

In order to manufacture the blast furnace outlet molding material refractory having the composition ratio as shown in Table 1 was added to the universal kneader for weighing the refractory material refractory kneading into a universal kneader for kneading refractory kneading kneading to dry uniformly by adding a little bit of water . The specimens were molded in a mold of 40 × 40 × 160 mm, naturally dried in air for 24 hours, and then dried at 110 ° C. for 24 hours in a dryer. The dried specimen was calcined at 1000 ° C. for 3 hours in an electric furnace to measure the bending strength. The corrosion resistance test was carried out using a blast furnace slag in a small high-frequency induction furnace (capacity 3kg) for 1 hour at 1500 ° C, and wired out to measure the remaining thickness of the specimen. The workability test measured the spread state of the sample when the kneaded sample was put into the mold of the fluidity tester and hit 30 times, and then the mold was removed. The thermal shock resistance was applied to a 50 x 50 mm specimen prepared in an electric furnace heated to 1300 ° C, taken out again after 30 minutes, cooled in air, and then cracked and edges generated in the specimen during 20 repeated heating and cooling processes. The appearance of the back was observed.

As can be seen from Table 1, Examples 1 to 5 satisfying the scope of the present invention is relatively small compared to Comparative Examples 1 to 4 and the prior art, the line change rate is relatively small, the plastic strength is large and excellent corrosion resistance Could.

division Example Comparative example Conventional One 2 3 4 5 One 2 3 4 Sintered Alumina 48 54 52 60 49 44 62 55 53 15 Silicon Carbide 13 11 12 10 10 15 8 10 11 - Silicon nitride 6 7 6 6 9 7 4 10 8 - Calcined alumina 7 6 8 6 10 11 6 4 7 - Chromium oxide 10 8 8 7 7 5 5 11 7 - Ceramic fiber 8 6 7 5 5 10 5 4 4 - Metal Al powder 2 4 2 2 3 5 2 One One - Alumina cement 6 4 5 4 7 3 8 5 9 8 Boki Site - - - - - - - - - 65 clay - - - - - - - - - 7 Silica fine powder - - - - - - - - - 5 Workability ◎ ◎ ◎ ◎ ◎ × × × △ △ Rate of change (%) -1.20 -1.28 -1.34 -1.28 -1.37 -1.64 -1.87 -1.97 -2.01 2.63 Bending strength (㎏ / ㎠) 73 70 76 79 78 62 68 60 61 68 Corrosion resistance (erosion thickness mm) 2.30 2.65 2.48 2.64 2.93 3.10 3.23 3.13 3.34 4.67 Thermal shock resistance ◎ ◎ ◎ ◎ ◎ △ × × × × ◎: Good X: Bad △: Normal

As described above, the blast furnace outlet molding material refractory according to the present invention has excellent thermal shock resistance, erosion resistance and high strength, so that it is used in the site of contact with molten iron at a high temperature such as blast furnace outlet, which has an excellent effect on protection of the outlet. It is a useful invention.

While the invention has been described in detail above with reference to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope and spirit of the invention, and such modifications and variations fall within the scope of the appended claims. It is also natural.

Claims (2)

Sintered alumina 48-60 wt%, silicon carbide 10-13 wt%, silicon nitride 6-9 wt%, calcined alumina 6-10 wt%, ceramic fiber 5-8 wt%, metal Al powder 2-4 wt%, and alumina Blast furnace outlet molding material refractory composition comprising 4 to 7% by weight of cement. The method of claim 1, The alumina content of the ceramic fiber (fiber) is in the range of 30 to 60% by weight, the length of the fiber is blast furnace outlet molding material refractory composition, characterized in that.