JPS5957968A - Blast furnace tap hole sealing material - 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 plugging material for blast furnace tapholes (hereinafter referred to as plugging material), and its purpose is to determine the amount of organic binder added to the plugging material without impairing workability. The object of the present invention is to provide a plugging material with improved durability by stabilizing the structure of the plugging material, which undergoes the most severe firing process among monolithic refractories.

The following requirements are required for the plugging material for the blast furnace.

(,) Workability is such that it has enough plasticity to easily fill the closed base material into the blast furnace tap hole with a mud gun, and that the hole opening operation can be performed easily when opening the tap hole. (b) Hardening. Sinterability is determined by the completion of hardening and sintering to maintain the plugging after the plugging material is filled into the blast furnace tap hole until the next hole is opened. It can withstand mechanical or chemical erosion caused by extraction, and the diameter of the tap hole does not expand from the initial stage to the final stage.

Conventional occlusion materials include chamotte, Rouseki, alumina,
A plugging material was used, which was made by kneading a refractory raw material such as magnesia, a carbonaceous raw material such as coke, and an organic binder such as tar into fireproof clay as a plasticizer and sintering material. However, in recent years, as blast furnaces have become larger and operated at higher pressures, the load on the plugging material has become extremely high, leading to a reduction in the tapping time and the loss of hot metal at the final stage of tapping.

The scattering of slag was interfering with the stable operation of the blast furnace.

To solve this problem, refractory aggregates and binders are generally made more sophisticated, such as by increasing the amount of alumina raw material, adding silicon carbide, or adding organic bonding resin binders such as phenolic resins. Although the results have been achieved, the current situation is that they are not fully satisfied.

In view of the above-mentioned current situation, the present inventors have repeatedly conducted basic research and examination of the sintering mechanism of the plugging material, and have developed a plugging material that has a stabilized structure and improved durability.

That is, the plugging material is heated to 50 to 60°C in the mud gun before filling by radiation of residual heat from the tap hole, but the temperature in the taphole plugging hole is 1500°C or higher. The plugging material filled here undergoes a rapid temperature rise. For this reason, it was found that the volatile matter in the organic binder contained in the plugging material caused a rapid boiling phenomenon and destroyed the structure of the plugging material during the firing process.

Therefore, even when high-grade bone materials such as alumina and silicon carbide or interstitial organic binders such as phenol resins are used, similar structural destruction occurs, and the effects cannot be fully exploited. Reducing the amount of organic binder is effective in reducing the above phenomenon, and the occluding material according to the present invention is a stable occluding material that does not cause tissue destruction even due to rapid evaporation of volatiles contained in the organic binder. This is what I got.

The present invention will be explained in detail below.

The refractory raw materials used in the present invention include common chamotte, alumina, Rouseki, zircon, magnesia, and a mixture of two or more of them, such as graphite, electrode scrap, coke, pitch, casen black, Kergan fiber etc.

One or more types of ultrafine powder selected from alumina, silica, silicon carbide, zircon, and synthetic silom oxide with an average particle size of 5μ or less are added to the commonly used mixture of the above refractory raw materials and carbonaceous raw materials. Add 10% by weight. By adding 1 to 10 weight percent of the ultrafine powder having an average particle size of 5 μm or less, the amount of organic binder added to impart plasticity to the plugging material can be greatly reduced.

The ultrafine powder of 5 microns or less used in the present invention includes crystalline refractory raw materials such as alumina, silica, silicon carbide, zircon, synthetic silicon oxide, and ferrosilicon.

Amorphous spherical ultrafine silica powder called silica flour, which is a collected dust produced as a by-product of metasilicon alloy production or zirconia production, or ultrafine powder of hyuusto silica powder, preferably silica flour, and particularly ultrafine alumina powder. Addition of organic binder is effective in reducing JJk.

If the amount of these ultrafine powders added is less than 1 part by weight, the dispersion in the matrix will be insufficient and the effect of reducing the amount of binder will not be obtained.On the other hand, if the amount of ultrafine powders added exceeds 10 parts by weight, The ultrafine powder aggregates and loses its ultrafine nature, and the amount of organic binder increases.

Furthermore, since the matrix is filled with ultrafine powder and the pore diameter is small, the evaporation of volatiles in the organic binder is also inhibited, making it impossible to stabilize the structure.

Addition of organic binder 11 due to the effect of the ultrafine powder mentioned above
1-Although it was possible to reduce the amount by 1, there remains a problem as a occluding material with this alone. That is, the organic binder in the plugging material is heated in the taphole after being filled, causing a decrease in viscosity as the temperature rises. This may cause leaching of the organic binder from the plugging material, which may cause structural defects in the taphole after the plugging material has hardened, or if the plugging material is filled with a mud gun and the mud gun is pulled away. It can also cause trumpet-shaped damage at the hole opening, which is called the perforation area. When ultrafine powder is added to reduce the amount of organic binder, the viscosity of the organic binder increases during filling into the taphole. As the hardness decreases, the plasticity becomes poor.With closed!B materials that have poor plasticity, cracks may occur in the plugging material during press-fitting, and drilling failure may occur due to a decrease in the taphole depth, hot metal seepage, etc. Fireclay is generally used as a plasticizer.Fireclay is heated and its viscosity decreases as the temperature rises, and it captures the excess organic binder and prevents it from seeping out. It maintains its plasticity as an adsorbent clay.However, fireclay is susceptible to slag, which causes a decrease in its durability.

The present inventors have found that the above plasticizer is strong against slag,
In addition, we have discovered the usefulness of earthy graphite, which prevents leaching and exhibits plasticity as a material characteristic, similar to fireclay. Therefore, in the product of the present invention, 1 to 10% by weight of earthy graphite is further added. If the amount of earthy graphite added is less than 1 weight, plasticity will not be exhibited, nor will leaching of the organic binder be prevented. Also 10% by weight
If the amount is exceeded, the amount of organic binder used increases, and conversely, the solvent and volatile substances in the organic binder evaporate, resulting in a lack of stability of the structure.

As the organic binder used in the plugging material of the present invention, organic binders commonly used in plugging materials such as coal tar, pitch, tall oil, phenol resin, and furan resin can be effectively used.

Furthermore, among organic binders, phenolic resins develop strength faster than other binders and exhibit high sintering strength, so their usage is gradually increasing.

However, phenolic resin-based coal tar (500 to 1
8,000 compared to organic binders such as 200CPS/30℃)
Since it has a high viscosity of ~50,000 CPS/30°C, the amount of phenolic resin added for crosstalk tends to be larger than that of coal tar etc., and the amount of volatile matter is higher than that of other organic binders. When resin is used as a binder, the amount of resin added is greatly reduced compared to conventional binders, which improves the ability to destroy structures due to boiling of volatiles.However, as a way to take advantage of the resin's high strength, it is possible to reduce the viscosity of the resin itself. It is necessary to reduce the amount added.

However, a method for lowering the viscosity in a phenolic resin system is to reduce the amount of resin. There are methods of reducing the molecular weight of resins, but all of these tend to reduce the inherent strength characteristics of phenolic resins.

After further consideration of the above problems and development, we found that the weight ratio of novolac type phenol resin and benzylic ether type thermosetting phenol resin in the phenolic resin system was 95:5 to 60:40. The resin binder, which is a phenolic resin mixed with 20 to 70% by weight of carpitol or a mixture of carpitol and glycol as a solvent, has a low viscosity of 100 to 20,000 PS/30°C, and a low surface tension of 33 to 42 dyn/cy+r. , is effective in reducing the amount of resin binder and thus contributes to the above-mentioned structure improvement.

The novolac type phenolic resin of the resin binder of the present invention is a thermoplastic resin with a melting point of 45 to 75°C.

Furthermore, benzylic ether type thermosetting phenolic resin is a viscous or semi-solid resin with a viscosity of 500°C at 50°C.
It is a resin having a CPS of 0 to 50,000 and exhibits strong characteristic absorption based on benzolic ether bonds in its infrared absorption spectrum i'11060crn, and does not thermoset at temperatures below 130°C.

In addition, the phenols that can be used as raw materials in the production of the above-mentioned Nogelac type phenol@J fat and the above-mentioned benzylic ether type thermosetting phenolic resin are phenol, noyalacresol, and metacresol.

3,4-xylenol, 3,5-xylenol or a mixture thereof.

The benzylic ether type thermosetting phenolic resin used as a curing agent does not heat cure at temperatures below 13'OC, and its curing temperature is higher than that of hexamine or resol type phenolic resins, which are commonly used as curing agents. When a benzylic ether type thermosetting phenol resin is used as the agent, the plugging material does not seize in the mud gun when filling the plugging material, and the filling workability is excellent.

The weight ratio of novolak type phenolic resin and benzylic ether type thermosetting phenolic resin is 95 = 5 ~
60:40 is preferred. If the amount of benzylic ether type curable phenol resin as a curing agent is less than 5% by weight, the strength development is slow and the hot strength is J-sized. On the other hand, if it exceeds 40 gw, the hot strength decreases. What about this resin binder? Calpitol or a mixture of carpitol and glycol is blended in an amount of 20 to 70% by weight with a lac type phenolic resin and a benzylic ether type thermally N-oxidizing phenolic resin.

Calpitol is carpitol or carpitol derivatives such as methylcarpitol, diethylcarpitol, methylethylcarpitol, etc. alone or in combination. Further, the mixture of calpitol and glycol is a mixture of calpitol and glycols such as ethylene glycol, diethylene glycol, and telopylene glycol.

When the amount of carpitol or carpitol mixture as a solvent is less than 20 times, the viscosity reducing effect by the solvent is small;
Furthermore, if 70 or more layers are used, the viscosity as a resin binder decreases too much and the unique plasticity of the clogging material cannot be achieved.

An example will be explained below.

Table 1 shows the results of first heating and kneading mixed materials with the mixing ratio to 50°C, creating specimens for each test, and conducting rapid heating tests.
As shown in Table 1, in conventional products 1 and A2, "blister" was observed due to rapid evaporation of the solvent, and the internal structure had pores due to evaporation.

It was confirmed that cracks had developed. In Conventional Products Store 3, the amount of resin binder added was as low as 10.5 inches (external), but the plasticity was poor and the product was dry. In the rapid heating test, phenolic resin oozed out when the specimen was heated, and the specimen collapsed. In addition, resin seeps out inside, and coarse pores are significantly developed.

In the product A4 of the present invention, the amount of tar added is 11% (outer layer), and in A5, the amount of added phenol resin glycol solution conventionally used is 13% (outer layer). In A6, the phenolic resin of novilac type phenol national resin: pengylic ether type thermosetting phenol resin = 8 = 2 and the solvent was carpitol alone, and resin binder I with resin: solvent = 55:45 was used, and the amount added was 11% ( For A7, phenol tenae iji of Noblak type phenol resin: penzolic ether type thermosetting phenol resin = 7:3 and calpitol: diethylene glycol = 7
= 3 solvent, resin: solvent = 55:45; u
'AW binder 11e is used, the amount added is 11.5
By using υ and resin binders ■ and ■, it became possible to reduce the amount of resin to a level almost equal to the amount added when coal tar or the like was used. As described above, in the product of the present invention, the amount of organic binder added was significantly reduced compared to the conventional product.

Although these have a small amount of binder, they have good plasticity, and almost no structural defects are observed even in rapid heating tests. Corrosion resistance was also greatly improved due to the above structural improvement effect.

Invention product A4. As a result of using Flat 5 and A7 in an actual furnace,
Workability in front of the furnace was the same as before. Especially A
In No. 7, there were no failures in closure due to burning of the closure material during closure, and stable closure work was performed.

In the product of the present invention, the rapid expansion of the tap hole at the end of the tapping stage and the scattering of hot metal slag, which were observed in the conventional mud material, were significantly reduced. Additionally, the tapping time was extended by 20 to 30%, and the number of taps per day was therefore reduced, resulting in a significant improvement in the unit consumption of plugging material.

Claims (1)

[Claims] 1, 7 Yamatsuto, alumina, Rouseki, zircon. Magnesia and one or more types of refractory raw materials such as silicon carbide;
A carbonaceous raw material such as coke, and 1 to 10% by weight of one or more types of ultrafine powder selected from alumina, silica, silicon carbide, zircon, and synthetic chromium oxide with an average particle size of 5 μ or less,
A blast furnace tap hole blocking material made by adding and kneading 1 to 10 weight of earthy graphite and an organic binder thereto. 2. As the organic binder, use Phenol 41111tf in which the ratio of Noblak type phenol resin and benzylic ether type thermosetting phenol resin is 95 = 5 to 60:40 by weight, and Calpitol or Calpitol and glycol as the solvent. 2. The blast furnace tap hole closing material according to claim 1, which is obtained by blending a mixture of 20 to 70 double fluorite.