JP2007147132A - Construction method for refractory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability with a view to decreasing damage and refractory unit requirement due to severity increase of recent treatment conditions, by force-feeding a monolithic refractory without causing hose clogging in repairing a refractory of a molten metal container of an RH facility or the like. <P>SOLUTION: In the construction method for a refractory used in construction using pump force feeding, firstly, a material A with a fine top size of used particles is force-fed, then, a material B with a coarse top size of used particles is force-fed to be integrated. The material A with the fine top size is the monolithic refractory composed of particle sizes of five milimeters or less, and the material B with the coarse top size is composed of particle sizes of 20 milimeters or less. The material A with the fine top size and the material B with the coarse top size can be force-fed and filled by pump force feeding of a concrete pump or the like. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a method for constructing a refractory used for repairing a kiln or degassing tank in the refractory field.

Conventionally, high-grade steel grades have been refined due to improvements in out-of-furnace refining techniques such as vacuum degassing and ladle refining, and the processing conditions have become severer accordingly. Therefore, it is desired to further increase the durability of the irregular refractories for refining outside the furnace.

In particular, in the vacuum degassing RH method equipment (hereinafter referred to as RH equipment), the reflux pipe, the dip pipe, and the lower tank are severely damaged, and repairs are frequently performed during operation. As general repair methods, JP-A-2000-160232, JP-A-8-020815, JP-A-5-3326.
Insert a refractory that becomes a sleeve when replacing a dip tube as described in No. 84, etc., an iron pipe, and use a concrete pump such as a mini cleat to damage a circulating pipe wall, lower tank bed, etc. A press-fit repair is carried out to pump the repair material.
JP 2000-160232 A JP-A-8-020815 JP-A-5-332684

An amorphous refractory used as a repair material is generally applied with an alumina-magnesia material excellent in corrosion resistance, etc., but because it is pumped, the raw materials used are also limited to a particle size of about 3 to 5 mm, Moreover, in order to give fluidity | liquidity etc., durability was inferior compared with the alumina-magnesia material etc. which are normally used with a ladle etc., such as the amount of additional water required more than a normal casting material.

In addition, the use of high-performance pressure feeders in ladles, etc., and the technology for pumping irregular refractories including coarse grains and steel wires have been established. However, problems such as particle clogging in the hose during pumping have been established. In order to prevent this, mortar is filled and pumped, and if it is confirmed that the material comes out of the hose, the mortar sealed by filling the tip and the mixed material of mortar are removed and construction is performed. ing.

However, pumping with an RH facility requires pumping with a hose or an iron pipe in the entire construction process, and it is impossible to remove a tip sealing material such as mortar.
Therefore, in the RH facility, it is difficult to perform press-fit repair with a tip seal with a mortar or the like which is a measure for preventing the clogging of the hose. For this reason, in recent years, durability that satisfies customer needs such as increased damage due to severe processing conditions and improved durability for the purpose of refractory unit consumption has not been obtained.

The present invention has been made in view of the above points, and in order to solve the above-described problems, in the construction method of the refractory used in the construction by pumping, first, the fine material A having the top size of the used particles is used. The object of the present invention is to provide a method for constructing a refractory, characterized in that a material B having a top size of used particles is subsequently pumped and integrated by pumping.

The fine top-sized material A is an amorphous refractory composed of a particle size of 5 mm or less, and the coarse top-sized material B is an amorphous refractory composed of a particle size of 20 mm or less. It is in providing the construction method of a thing.

Still another object of the present invention is to provide a method for repairing a refractory such as a kiln or the like, wherein the top-sized fine material A and the top-sized rough material B are pumped and filled by pumping such as a concrete pump.

The refractory construction method of the present invention is a refractory construction method used in construction by pumping. First, the material A having a fine top size of the particles used is first pumped, and then the coarse material having a top size of the particles to be used. By integrating B by pumping B, it is possible to reduce the cracks / peeling and melting damage of the molten metal container or the like and perform repairs or the like that can obtain high durability.

In addition, the top-size fine material A is an amorphous refractory composed of a particle size of 5 mm or less, and the top-size coarse material B is an amorphous refractory composed of a particle size of 20 mm or less. By using an irregular refractory with different particle diameters, it is possible to carry out an irregular refractory with a large particle diameter, which has been difficult in conventional RH facilities.

Furthermore, repairing of molten metal containers such as kilns, vacuum degassing tanks, ladles, etc. is easy by filling the top-size fine material A and the top-size coarse material B by pumping such as a concrete pump. The durability can be increased.

The refractory construction method of the present invention is a refractory construction method used in construction by pumping. First, the material A having a fine top size of the particles used is first pumped, and then the coarse material having a top size of the particles to be used. B is pumped and integrated.

The construction method of this refractory kneads a predetermined amount (for example, about 100 kg) of an amorphous refractory composed of 5 mm or less of the top particles used at the start of construction, and fills the hose by pressure feeding. Thereafter, an amorphous refractory composed of 20 mm or less of the top particles used is kneaded and pumped.

In addition, in pressure feeding repairs at RH facilities, etc., the hoisting pipe side, the descending pipe side, and the hose are connected to each other and pressure feeding may be performed. In this case, the top end portion of the hose is composed of 5 mm or less. It becomes possible to pump by filling a predetermined amount (for example, about 25 kg) of the amorphous refractory.
In the present invention, it has become possible to pump an amorphous refractory having a large particle shape by using the conventional press-fit repair material as a filler to the tip of the hose.

The major feature of the present invention is that the material is prevented from being separated and clogged even in the sleeve brick and the iron pipe for repair by filling the tip of the hose with an irregular refractory composed of 5 mm or less of the top particle used. It is in the point where pressure feeding construction became possible.

The particle size of the material used for filling the hose tip is preferably 5 mm or less to 1 to 5 mm. If the particle size is 5 mm or more, a material separation phenomenon occurs and clogging occurs in the hose. More preferably, the top particle size is 3 mm or less to 1 to 3 mm.

After the inside of the hose is sealed with a filler, the particle size of the material to be pumped is preferably 20 mm or less. If it is 20 mm or more, the particle size becomes too large, and the particles come into contact with and clog in the hose. More desirably, the top particle size is desirably 12 mm or less.

The amorphous refractory composed of 5 mm or less of the top particles used for filling the tip of the hose varies depending on the length of the hose to be pumped and the output of the pump, but if it is 20-30 m,
It can be filled with about 25kg.

For example, in the press-fit repair in the RH facility, the furnace temperature at the time of repair is 300 ° C ~
It is a construction method in which the construction is carried out between about 800 ° C. and hot, and the whole construction process is pumped in the hose or the iron pipe. Therefore, the characteristics required of the material are the material design centered on workability such as fluidity, the particle size used is subject to many restrictions, and the amount of added water is also normal pumping material etc. to ensure fluidity Even if compared, it tends to increase.

Therefore, compared with a normal pumping material etc., the porosity etc. were high and the intensity | strength was also low.
The biggest problem of press-fit repair in the RH facility is in how to press the material to the repair site, and we examined how to overcome this point. As a result, after sealing the tip of the hose at the start of pumping by filling with a conventional press-fitting material, it becomes possible to pump the material of coarse particles as in the present invention.

When the particle diameter is made coarse, the amount of added water can be relatively reduced, the material can be densified, and it has an advantage over melting and peeling.

The refractory raw material to be constituted is not particularly limited as long as it is used for ordinary amorphous refractories, and one or two of alumina, magnesia, zircon, spinel, dolomite, calcia, mullite and the like Two or more species can be used in appropriate combination.

The binder is not particularly limited as long as it is generally used for amorphous refractories such as alumina cement, alumina sol, or silica sol.

In addition, as for the dispersant, if it is usually used for amorphous refractories such as ultrapolyphosphate soda, acid hexmetaphosphate soda, hexmetaphosphate soda, tripolyphosphate soda, polyacrylate soda, naltalene sulfonate, etc. There is no particular limitation.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples of the present invention. As an experiment for explaining the present invention, in order to evaluate the press-fitting conditions assumed in an actual machine by a laboratory test, the height is put into an experimental furnace 2 held at 800 ° C. by a heating rod 1 as shown in FIGS. 600mm, width 380mm,
A frame 3 having a construction thickness of 60 mm was installed, and the press-fitting material was pumped. A general squeeze-type concrete pump 4 was used as a condition for pressure feeding. Moreover, the hose 5 used at the time of pressure feeding used the material hose generally used by concrete construction etc., and pressure-fed on the conditions of a hose diameter of 1.5 inches and length 20m.

At the time of pumping, 25 kg of the material of the top particle 3 mm used is pumped first, and the experimental furnace 2 is filled with the press-fitting material until it is confirmed that the material of the top particle 3 mm has completely overflowed from the inside of the frame 3. Then, the press-fitting material using coarse particles was filled in the frame 3.

As the level of the experiment, the particle diameter of the press-fitting material following the filler material at the tip (top particle 3 mm) was changed, and the pumping situation and various physical properties after pumping were confirmed. The material used was an alumina magnesia material based on sintered alumina and using seawater magnesia clinker.

As comparative examples, Comparative Example 1 is the one in which the material of the top particle 3 mm is pumped in full amount, Comparative Example 2 is the one in which the material of the top particle 8 mm is pumped in full amount, and Comparative Example 3 is the top particle after the material of the top particle 3 mm is pumped. 30 mm of material is pumped. The results are shown in Table 1.

Table 1 Examples and Comparative Examples

In Comparative Example 1 in which the material of the top particle 3 mm was pumped in total, compared with Example 1-5, when the physical properties after hot press-fitting were compared, the porosity was high as shown in Table 1, and the bending strength was also low. Yes. In addition, the test piece after press-fitting was cut out and subjected to a rotary rotary erosion test, and the amount of erosion was about 10% larger than that in Example 1, and the material was densified by using coarse grains together. The effect of is recognized.

On the other hand, in Comparative Example 2 in which the top particles were 8 mm, clogging occurred in the hose being pumped. 5
Single pumping of materials using coarse particles of mm or more is difficult because of hose clogging due to separation of coarse particles and fine powder at the pumping tip. Moreover, although the comparative example 3 was able to pump in the middle, when switching to the material of 30 mm of top particles, the discharge pressure of the squeeze pump rose rapidly and tripped. When the inside of the hose was confirmed, the coarse particles and the coarse particles were in contact within the hose.
That part was an obstacle. Increasing the particle size is effective for reducing the amount of added water, but it becomes difficult to pump by the contact of the coarse particles in the hose.

About Example 2, the actual machine test was done as repair of a RH degassing reflux tube and a lower tank bed. As a result, the comparative example 1 which had a life of about 80 ch was improved to about 110 ch, and the effect was recognized even in an actual machine.

Thus, the top particle 5 used in the press-fitting construction of the kiln performed in the RH degassing tank or the like
By using a press-fit repair material with a diameter of not more than mm and a press-fit repair material with a top particle of 20 mm or less, fluidity is good as shown in Table 1, and even if a coarse material cannot be press-fitted alone, a trickle material should be first When filled through, it becomes possible to press-fit, reducing cracks / peeling and melting damage, RH
The durability of the lower tank and the reflux pipe can be improved.

Explanatory drawing for pumping experiment of the present invention, Simplified experimental furnace.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heating rod 2 ... Experimental furnace 3 ... Frame 4 ... Pump 5 ... Hose

Claims (3)

In the construction method of refractory used in construction by pumping,
First, a material A having a fine top size of used particles is pumped, and then a coarse material B having a top size of used particles is pumped and integrated to integrate the refractory. 2. The refractory according to claim 1, wherein the fine top-size material A is an irregular refractory having a particle size of 5 mm or less, and the coarse top-size material B is an irregular refractory having a particle size of 20 mm or less. Construction method. The method for repairing a refractory such as a kiln or furnace according to claim 1 or 2, wherein the top size fine material A and the top size rough material B are pumped and filled by pumping such as a concrete pump.

Images