JPH0717462B2 - Press-fit material for blast furnace wall repair - Google Patents

Description

TECHNICAL FIELD The present invention relates to a press-fit material for blast furnace wall repair, which has excellent durability.

(Prior Art) The refractory lining in a blast furnace is significantly damaged by the wear action of the contents of the furnace such as ore and coke due to the unloading of the contents of the furnace, and the chemical reaction by the alkaline components coming from the contents of the furnace.
Especially, the lower part of the shaft and the bosh area are greatly damaged. If the refractory lining becomes thin due to this damage, it will cause hot spots or cracks in the iron shell, which will greatly hinder stable operation of the blast furnace.

Therefore, conventionally, a small hole is formed in the iron shell during the operation of the furnace, and an amorphous refractory material is press-fitted through the small hole to repair the melted portion of the lining.

Various press-fit materials used for this repair have been conventionally proposed. For example, one using powdered alkali silicate as a binder (JP-A-55-113677), one containing a furan resin as a binder (JP-A-57-118073), or heat resistance as a tissue reinforcing material. Examples thereof include fibers added (Japanese Patent Laid-Open No. 50-45009).

(Problems to be Solved by the Invention) However, the press-fit material using powdered alkali silicate or furan resin as a binder cannot obtain sufficient structural strength and is inferior in wear resistance and alkali resistance. In particular, in the case of using powdered alkali silicate, water is added at the time of construction, so when the furnace heat is applied after press-fitting, the boiling of water causes the structure to become porous and the adhesion to the furnace wall to deteriorate. Further, the one to which the heat resistant fiber is added cannot obtain the expected effect because the fiber causes generation of a low melting point substance and the strength of the fiber is lowered at a high temperature during use.

Further, since the press-fitting repair must be performed within a limited time when the blast furnace is in a blast, and quick construction is required, the press-fitting material is required to be a material having low resistance to pumping.

It is an object of the present invention to provide a press-fitting material which can sufficiently cope with the wear effect on the furnace wall of the blast furnace and the damaging effect such as alkali erosion, and has a small resistance to pumping.

(Means for Solving the Problems) The present invention is for use in a blast furnace furnace wall provided with a cooling means, wherein 100 parts by weight of refractory aggregate, 5 to 40 parts by weight of graphite, and liquid phenol are used. It is an admixture for repairing a blast furnace wall by adding 5 to 80 parts by weight of resin and / or furan resin and 0.1 to 10 parts by weight of metal fiber.

The addition of heat resistant fibers such as metal fibers to the press-fit material is known, for example, in the above-mentioned Japanese Patent Laid-Open No. 50-45009. However, even though these fibers have heat resistance, they are inferior in corrosion resistance to fire-resistant aggregates, and their strength is reduced by furnace heat, so that sufficient effects cannot be exhibited.

On the other hand, in the present invention, the heat-resistant fibers are limited to metal fibers having excellent thermal conductivity, and by combining this with a liquid phenol resin and / or furan resin as a binder, it is required for a blast furnace press-fit material. It has improved abrasion resistance and alkali erosion resistance.

The blast furnace wall is cooled by a stave cooler or a water cooling jacket. Due to its thermal conductivity, the metal fiber propagates the water cooling effect to the press-fit material structure. However, since the metal fibers exist discontinuously in the press-fit material structure, the cooling action is not sufficiently propagated. The present invention solves this problem by using a phenolic resin and / or a furan resin as a binder together with the addition of metal fibers.

That is, when the binder is carbonized by receiving heat in the furnace, a carbon component having thermal conductivity exists between the metal fibers, and the cooling action of the metal fibers is cut off between the metal fibers. There is no. By keeping the temperature of the press-fitting material low by this cooling action, there are effects of improving wear resistance by preventing deterioration of fiber strength and preventing alkali erosion by suppressing reaction. Further, since the binder is a non-aqueous type, there is no porosity of the tissue due to the boiling found in the aqueous type.

In the formulations of the examples shown in the table below, the kind of binder and the addition ratio of metal fibers were changed, the thermal conductivity was measured for each, and the results are shown in a graph in FIG. From the graph, it can be seen that the thermal conductivity of the non-aqueous phenol resin or furan resin is more significantly improved by the addition of the metal fiber than the one using the aqueous binder powder sodium silicate.

Graphite powder is further added to the press-fit material of the present invention. Graphite powder has the effects of further improving the thermal conductivity and eliminating the decrease in pumpability that is observed when a large amount of metal fibers are added.

Hereinafter, the present invention will be described in more detail.

The refractory aggregate used in the present invention is alumina, alumina-
One or more selected from silica, magnesia, spinel, etc. as the main material, if necessary, one selected from silicon carbide, silicon nitride, chrome ore, clay, zircon, zirconia, silica, chromium oxide, etc. Alternatively, two or more kinds are combined in an appropriate amount. The selection of these refractory aggregates is no different from conventional materials. Further, the particle size constitution may be the same as that of the conventional material.

The binder is a liquid phenol resin and / or furan resin. If necessary, the viscosity of liquid phenol resin / furan resin is adjusted with alcohols and ethers.
The preferred viscosity is 10 to 200 centipoise.

When the proportions of the phenol resin and furan resin, each alone or in combination, are less than 5 parts by weight with respect to 100 parts by weight of the refractory aggregate, the press-fitting property of the press-fitting material is poor and sufficient thermal conductivity cannot be obtained. If it exceeds 80 parts by weight, the structure of the press-fitting material becomes porous, resulting in poor durability.

Further, a curing agent may be added. As the type of this curing agent, those known as curing agents for citric acid, malic acid, tartaric acid and other liquid resins can be used.

The metal fiber is most preferably stainless steel from the viewpoint of heat resistance, but is not limited to this, and examples thereof include iron, carbon steel, and Cr-Mo.
Steel, Cr steel, Cr-V steel, Al, Al alloy, Cu alloy, etc. may be used. The shape may be straight, curved, chevron-shaped, or wavy. The size is 0.1-1mm in diameter, and the length is 5-50 of the diameter.
About twice (for example, 5 to 40 mm) is preferable. If the addition ratio is less than 0.1 parts by weight with respect to 100 parts by weight of the refractory aggregate, the cooling effect is not recognized, and if it exceeds 10 parts by weight, the fire resistance of the press-fit material decreases.

As the graphite powder, for example, earthy graphite, phosphorous graphite, waste graphite material, etc. can be used. The particle size is, for example, 1 mm or less, preferably 0.1
mm or less. The ratio is 4 to 100 parts by weight of refractory aggregate.
It is 0 parts by weight or less. If it exceeds 40 parts by weight, the oxidation resistance of the press-fitting material will deteriorate.

FIG. 2 is a graph showing the change in press-fit resistance when only the amount of graphite powder added was changed in the formulation of Example 10 described later. From the graph, in order to sufficiently obtain the effect of adding the graphite powder, the ratio is set to 5 parts by weight or more. The thermal conductivity and the press-fitting resistance shown in the graphs of FIGS. 1 and 2 were measured by the same methods as those described in the section of Examples below.

In addition to the above-mentioned refractory raw materials and additives, the press-fit material of the present invention may be added with an appropriate amount of metal powder, organic fiber, dispersant, etc. as long as the effects of the present invention are not impaired.

And, the press-fitting material of the present invention, in the repair of the lining of the blast furnace furnace wall provided with a cooling means such as a stave cooler or a water-cooling jacket, a piston type or squeeze type pressure-feeding device is used, and a press-fitting hose is applied to the furnace wall. The part to be repaired is press-fitted through the provided hole.

(Examples) Table 1 shows examples of the present invention and comparative examples thereof.

The test methods shown in the table are as follows.

Porosity, thermal conductivity and bending strength are
What was dried at 110 ° C. × 24 hrs was measured.

The actual machine test was performed by press-fitting and repairing the lining on the shaft portion of the blast furnace equipped with the cooling means.

In the case of using powdered sodium silicate as a binder, 20% by weight of water was added to the whole composition, and the work was performed.

Porosity: Measured according to JIS 2205-74.

Thermal conductivity; After heating the sample at 700 ℃ in reducing atmosphere,
It was measured.

Abrasion resistance: After heating the test piece at 700 ° C in a reducing atmosphere,
Measured by the sandblast method. The wear size of Comparative Example 1 is 100
The wear resistance is superior as the value is smaller.

Bending strength; span of 100m for test pieces cast into 40 × 40 × 160mm
Measured in m.

Pumping resistance: When a refractory was pumped at a rate of 0.1 m ³ / min into an iron pipe having an inner diameter of 50.8 mm and a length of 500 mm, the shear bond stress of the refractory at the proximal end of the pump was measured.

Service life: The service life was determined by increasing the temperature of the steel shell.

Time required for press-fitting: When a piston type pump was used and press-fitting was performed through a press-fitting hose having an inner diameter of 25 mm, the time required for completion of press-fitting of 300 kg of press-fitting material was measured.

(Effect of the invention) As is clear from the tests of the examples, the press-fit material of the present invention has improved thermal conductivity due to the combined use of a metal fiber and a resin binder, and can be cooled with water from a cooling means such as a stave cooler or a water cooling jacket. The action is propagated to the entire press-fitting material, and the operating temperature of the press-fitting material can be lowered. As a result, the strength of the metal fiber is not deteriorated, and the erosion effect of alkali from the furnace contents is reduced. In addition, by using the non-aqueous binder, there is no porosity of the structure as seen when the aqueous binder is used. As a result, the press-fitting material of the present invention showed a marked durability as shown in the data of the actual machine test.

In addition, graphite reduced the resistance to pumping, enabling quick construction.

[Brief description of drawings]

FIG. 1 is a graph showing the thermal conductivity of the press-fit material, and FIG. 2 is a graph showing the pumping resistance of the press-fit material.

Front Page Continuation (72) Inventor Akira Kojima 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Co., Ltd. Kimitsu Steel Co., Ltd. In-house (56) References JP-A-63-190766 (JP, A)

Claims (1)

[Claims] 1. A blast furnace wall provided with a cooling means, comprising 100 parts by weight of refractory aggregate, 5 to 40 parts by weight of graphite, and 5 to 5 parts of a liquid phenol resin and / or furan resin. A press-fit material for blast furnace wall repair that contains 80 parts by weight and 0.1-10 parts by weight of metal fibers.