JP2001098310A - Nonaqueous press-fitting material for repairing blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous press-fitting material for repairing a blast furnace, which forms a minute structure in the temperature range of 100 deg.C-400 deg.C and has excellent press-fitting workability and stability for hardening. SOLUTION: This nonaqueous press-fitting material is the one adding 80-120 pts.wt. binder mixing dissolving phenol resin and coal-tar at weight ratio of 20/80-50/50 with aromatic solvent to 100 pts.wt. refractory aggregate. Then this has <=10,000 cps viscosity at the working time and >=1,000 cps viscosity when the hardening starts, and the heat-up of an iron shell of the blast furnace is restrained and the service life of the blast furnace lining can be extended in the further safe state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous refractory which is press-fitted into a gap between a steel shell of a blast furnace and a fragile refractory, and more particularly to a non-aqueous press-fitting material.

[0002]

2. Description of the Related Art In recent years, blast furnaces have been increasing in size and operating conditions have become severer, and the causes of damage to the refractory lining due to high pressure operation, pulverized coal injection operation, etc., have increased, but the life of blast furnaces has increased. The target is to operate for 20 years, twice that of the past.

Naturally, the life of such a blast furnace depends on the refractory lining of the lining, especially the refractory layer of the brick or stamp formed on the inner side of the blast furnace to protect the blast furnace steel at the bottom of the blast furnace. Affected by lifetime.

The bottom of a blast furnace always has a temperature of 1450 ° C. to 1550 ° C.
Since the hot metal of ℃ is stored, damage of the refractory lining progresses, and when the refractory layer becomes thinner, the heat insulating effect by the refractory becomes weaker, and the temperature of the blast furnace shell increases. In other words, the temperature of the steel shell on the bottom wall of the blast furnace and the carbon block used inside (hereinafter referred to as the back of the carbon block) was around 100 ° C in the early stage of blast furnace burning, but it melted over the years of operation. As the layer becomes thinner due to the loss, the temperature in the blast furnace of 1500 ° C. or higher during the operation of the blast furnace is transferred to the bottom wall of the blast furnace and heats up to about 400 ° C. In such a state, the blast furnace shell is deformed by heat, and finally, the worst state occurs in which the blast furnace shell is cracked.

Therefore, the temperature of the blast furnace is reduced to about 100 ° C. or less by spraying water from the outside of the blast furnace to cool the steel shell itself or installing a stave cooler to cool the refractory lining. Restrained. Although the life of such a blast furnace is extended, if the blast furnace operation continues for a long time,
In the bottom wall of the blast furnace, the blast furnace steel shell is deformed due to thermal distortion due to long-term operation, and a gap is created between the blast furnace steel shell and the lining refractory layer, and this gap significantly reduces the thermal conductivity. As a result, an adiabatic action occurs, and the cooling effect is reduced, and the cooling effect is not sufficient.

[0006] Therefore, in order to repair the fragile portion of the lining refractory layer and the gap with the steel shell, a paste-like paste has been regularly placed on the back of the carbon block from the outside of the blast furnace to the inside of the blast furnace during the operation of the blast furnace. The cooling effect is increased by filling the gap between the blast furnace steel shell and the lining refractory material, that is, the air pool, with the press-fitting material by injecting the irregular-shaped refractory material, that is, the press-fitting material, and increasing the temperature of the blast furnace steel shell and the lining refractory material. The rise in temperature of the layer is suppressed.

However, most of the conventional press-fitting materials use alumina cement as a binder as a refractory raw material and a large amount of water is added. In this case, the temperature of the back surface of the carbon block where the press-fitting is performed exceeds 100 ° C. It is temperature and a considerable amount of water evaporates instantaneously, which forces it into a non-pressurizable state during the press-fitting operation. Further, since a large amount of water is added to the press-fitting material, the structure after the press-fitting has a high porosity, and furthermore, by evaporation of the water at the time of the press-fitting operation, alumina hydrate is not generated, so that the strength is hardly developed. Become.

Hitherto, many means have been proposed for solving such a problem that the effect of repairing the refractory layer of the press-fitting material is small. For example, Japanese Patent Publication No. Sho 30-3035 discloses a press-fitting material made of a thermosetting resin using hexamethylenetetramine as a curing agent in a novolak-type phenol resin. However, in this case, when the press-in material receives heat during storage of the press-in material or during the press-in operation, there is a problem that the viscosity is significantly increased and the press-in operation is likely to be disabled. In addition, Japanese Patent Publication No. 3-16398 discloses that
A press-fitting material in which a furan-modified resin is added without adding water is disclosed. However, the furan-modified resin is very expensive and the addition of an acid required for curing the furan-modified resin significantly degrades the curing properties even in a very small range, so that there is a problem of lack of practical stability. there were.

Further, such a press-fitting material becomes viscous from about 100 ° C. and loses fluidity to cause a rapid hardening reaction, which makes the press-in operation difficult. Also, at the press-fitting inlet provided in the blast furnace steel shell, after press-fitting, the press-fitting material discharge portion nozzle of the press-fitting machine receives the heat of the blast furnace furnace body, the press-fitting material remaining at the nozzle tip hardens, and the seizure phenomenon occurs, There is a problem that it takes time to remove and clean the cured material when the press-fitting is performed again, which also hinders the press-fitting work in other places.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem of the conventional press-fitting material.
For blast furnace repair, which has sufficient fluidity and curability in the temperature range of 0 ° C to 400 ° C, and is excellent in press-in workability and strength stability of the construction body, which can form a dense structure after curing. Provide non-aqueous press-fitting material.

[0011]

The non-aqueous press-fitting material for repairing a blast furnace according to the present invention is obtained by adding a phenol resin and coal tar dissolved by an aromatic solvent to 100 parts by weight of one or more refractory aggregates. 80-120 parts by weight of a binder mixed at a ratio of 20/80 to 50/50 in weight ratio of phenolic resin / coal tar dissolved by an aromatic solvent is added, and the viscosity at the time of construction is 10,000 cps or less. The viscosity at the start of curing is 1,000 cps or more.

As the phenol resin dissolved by the aromatic solvent of the present invention, a commercially available resin can be used as it is.

The dissolved phenolic resin used in the present invention must be mixed and dissolved with coal tar, and is in the form of a solution with an aromatic solvent adjusted to have an ortho / para ratio of 2 or more as a bonding position. There are three types of bonds: those where the bonds are at ortho positions with respect to the hydroxyl group of the phenol nucleus, those at the ortho-para position and those at the para position. The ortho / para ratio in the present invention is defined as the number of bonds between ortho positions, the number of bonds between ortho positions, and the number of bonds between para positions with respect to １ ／ of the sum of the number of bonds between para positions and the number of bonds between ortho and para positions. Means half of the sum of

That is, the ortho / para ratio is given by {(oo) + (op) / 2} / ｛(pp) + (o
When this ratio is 2 or less, the hydroxyl group of the phenol nucleus dissociates the tar from being dissolved, becomes a separated state, and the two are not mixed.

As the phenol resin used, there are two types, a resol type which cures as it is when heat is applied, and a novolak type which thermally cures by using a curing agent. As the aromatic solvent of the phenol resin, various solvents can be used as long as the main component is an aromatic compound. In consideration of avoiding rapid gasification at the time of injection of injection material, 2
It is desirable that two or more types be mixed at a volatilization temperature of 00 ° C. or higher. Specific examples include benzene compounds such as monomethylenebenzene, diethylbenzene, trimethylbenzene, tetramethylbenzene, xylene, and toluene, and indene nucleus compounds.

An ester which can be mixed with an aromatic solvent;
Furfuryl alcohol, creosote oil or the like may be used in combination.

The properties of the coal tar to be mixed are not particularly limited in its properties. For example, anhydrous tar or pitch can be prepared by adding creosote oil, anthracene oil, light oil,
Cutback tar dissolved with a solvent such as absorbent oil can also be used. These have many polycyclic aromatic hydrocarbons as components,
Although its molecular weight is as low as several hundreds, it has a high melting point,
For example, the liquid state is maintained even when heated to around 600 ° C. From this, it is advantageous as a press-fitting material binder as compared with other liquid binders which evaporate at a low temperature when heated and easily form voids. On the other hand, at 400 ° C. or lower, no carbon bond is formed, and the material does not harden even if it receives heat after press-fitting, but rather decreases in viscosity. Although it is small, good properties can be obtained by mixing it with a phenol resin dissolved in an aromatic solvent at a fixed ratio and using it as a press-fitting material.

That is, by combining the hardening characteristics of phenol resin by heating and the softening characteristics of coal tar by heating, a material having a viscosity of 10,000 cps at the time of construction is used in a real furnace, and 1,000 cp by heating.
The material is changed to a low-viscosity press-fit material having a viscosity of about s to sufficiently fill the gap between the steel shell and the refractory, and furthermore, a shape retaining property is obtained as a construction body.

The amount of the mixture of the phenolic resin dissolved with the aromatic solvent and coal tar used for obtaining the viscosity required in the present invention is 80 to 120 parts by weight based on 100 parts by weight of the refractory aggregate. The mixing ratio of the dissolved phenol resin and the coal tar is preferably 20/80 to 50/50 by weight of the dissolved phenol resin / coal tar. If the amount of the mixture of the dissolved phenol resin and coal tar is less than 80 parts by weight, the viscosity as the press-fitting material is high, and the press-fitting becomes impossible. If the amount exceeds 120 parts by weight, the press-fitting property is improved, but the structure is deteriorated. Furthermore, the mixing ratio of dissolved phenol resin / coal tar is 20/8
If it is less than 0% by weight and the amount of coal tar is too large,
In the case of using a novolak type, the effect is not improved even if hexamethylenetetramine as a curing agent is added in an amount of 10 parts by weight or more to the dissolved phenol resin. Cures slowly and has low strength.
On the other hand, if the ratio is larger than 50/50, the thermosetting properties of the phenolic resin become strong, and when the press-in machine receives heat, the viscosity increases significantly and the press-in becomes difficult.

In the production of the non-aqueous press-fitting material for repairing a blast furnace of the present invention, the phenol resin and the coal tar dissolved in the refractory aggregate by the aromatic solvent may be mixed in advance with each other. It can also be charged into a mixer. In order to impart thermosetting properties to a dissolved phenolic resin using a novolak type, a curing agent such as hexamethylenetetramine or MgO can be used, but some degree of curing characteristics are adjusted according to the amount of the curing agent used. can do. For example, when it is necessary to obtain a curing property at about 100 ° C. within 12 hours, it is necessary to add hexamethylenetetramine to the dissolved phenol resin in an amount of 5 parts by weight or more. However, addition of 10 parts by weight or more does not change the curing time, and has no effect of increasing the amount.

As the refractory aggregate used in the present invention, silicon carbide, coke, natural graphite, artificial graphite, calcined anthracite, pitch powder, carbon brick waste, electrode waste, fired waste are used in accordance with the material of the base material of the repaired part. Select from the group of sintered alumina, fused alumina, calcined alumina, rhoite, chamotte, pottery stone, clay, kaolin, bentonite, mullite, bauxite, ban shale, and use one or more of them as necessary it can.

The particle size of these refractory aggregates is not particularly limited.
It is desired to set it to 1/2 or less. However, it is preferable not to exceed 0.15 mm from the viewpoint of fluidity. This takes into account that the gap is not limited to 0.3 mm and that there are naturally many smaller places. If the gap of the press-fitting part exceeds 0.3 mm in particular, the air existing between the refractory and the blast furnace steel causes an adiabatic effect, and the temperature of the steel shell increases sharply, so it is necessary to repair immediately. . In this case, the particle size of the refractory aggregate should be 以下 or less according to the size of the gap, but the aggregate having a maximum particle size of 0.15 mm or less is considered in consideration of the unclear gap state. By using, the filling property of the press-fitting gap portion can be enhanced, and the repair effect can be improved.

The grain size of the refractory aggregate is defined as coarse grains near the maximum grain size, and as the size becomes smaller, the grains are classified into medium grains and fine grains, and these ratios are set to 30:40:30 or 20:40. : 40, fluidity during press-fitting can be ensured. If the particle size distribution is narrow, the aggregate and the liquid binder are easily separated at the time of the press-fitting work, and the press-fitting is liable to occur.

As a press-fitting machine into the blast furnace, a press-fitting machine such as a grout pump and a mortar pump can be used. The viscosity of the press-in material needs to be 10,000 cps or less at room temperature or even when it is heated to a temperature close to summer under use conditions in winter. Then, at the time of press-fitting, the press-fitting material is heated in the blast furnace and gasified at once, so that the press-fitting cannot be performed if the liquid phase portion in the solvent which functions as a lubricant at the time of press-fitting is lost. Therefore, the heated press-fitting material needs to be sufficiently soft. For this reason, the viscosity of the press-fit material before thermosetting is 1
However, if the viscosity before curing is less than 1,000 cps, the structure becomes poor due to the foaming phenomenon of the press-fitting material.

[0025]

Embodiments of the present invention will be described below with reference to examples.

The refractory aggregate used in each example was prepared by adjusting anthracite to a coarse particle size: medium particle size: fine particle ratio of 30:40:30 in accordance with the composition of the carbon block used in the bottom of the blast furnace.

Table 1 shows comparative examples together with examples of the present invention.

[0028]

[Table 1] The characteristic values of each sample shown in the table were measured in the following manner.

The viscosity was measured by kneading the pressed material for 30 minutes with a concrete mixer and using a B-type viscometer according to JIS K638.
It measured according to 1. The viscosity at 100 ° C. is such that the material temperature in a φ50 × 100 mm
Measured immediately after reaching 0 ° C.

The curing time at 100 ° C. is similarly indicated as the time at which the viscosity measurement with a B-type viscometer becomes impossible after the material temperature reaches 100 ° C. The desired curing time is
Considering the operating conditions of the blast furnace and the speed of filling and filling the gap,
It is about 240 minutes.

The viscosity and the curing time were measured 10 times.
The reason why the temperature was set to 0 ° C. was that the condition was determined based on the initial state of the blast furnace operation, and if the damaged portion was heated to 100 ° C. or higher, it was necessary to perform repair.

The compressive strength and apparent porosity are 40 × 40
Pour into a metal frame of × 160 mm, and after curing, raise the temperature to 350 ° C. at a rate of 70 ° C./hour, hold for 10 hours,
The measurement was performed according to JISR2553 and JISR2655, respectively.

The structure after the rapid heating at 350 ° C. is φ50 × 100
This is a result of visually observing the condition of the cut surface after being charged into a 350 ° C. electric furnace and held for 60 minutes in a state where a press-fitting material is cast into a metal frame of mm.

The success rate of the press-in operation was calculated as follows: the number of press-in ports that could be press-fitted under the condition of 150 kg / place / the total number of press-in ports that were press-fitted × 10
This is indicated by the result of 0.

In Example 1, the weight ratio of dissolved phenol resin / coal tar was 20/80.
The structure after the 0 ° C. rapid heating was good, and the press-in success rate was 95%.

In Example 2, the weight ratio of dissolved phenol resin / coal tar was 40/60.
The structure after 0 ° C rapid heating is also good, and the press-in success rate is as high as 95%.
The curing time at 100 ° C. was 60 minutes.

In Example 3, the weight ratio of dissolved phenol resin / coal tar was 50/50.
The structure after 0 ° C rapid heating is also good, and the press-in success rate is as high as 95%.
The curing time at 100 ° C. was 45 minutes.

Comparative Example 1 is a case where a normal novolak type phenol resin is used as a binder and hexamethylenetetramine is used as a curing agent. Since the curing time at 100 ° C. is short, the composition is cured during press-fitting, and the press-in success rate is the lowest result of 31%.

Comparative Example 2 was a case where coal tar was used as a binder. Although the press-in success rate was as high as 98%, a cured structure was not obtained and the repair effect was small.

In Comparative Example 3, a novolak-type phenol resin as a binder and 20/80% by weight of coal tar were used.
Are mixed in the ratio of, but there is no compatibility of both,
The novolak type phenol resin and coal tar separated.

In Comparative Example 4, a dissolved phenol resin and coal tar were used as binders in a ratio of 20/8 according to the present invention.
Although the mixture was mixed at a ratio of 10/90% by weight, which was less than 0% by weight, the viscosity at 100 ° C. became 1000 cps or less, a foaming phenomenon occurred, and it took 46 hours or more to complete the curing.

In Comparative Examples 5 and 6, the dissolved phenol resin /
The ratio of coal tar exceeds 50/50,
A foaming phenomenon occurred.

Examples 1 to 3 and Comparative Examples 4 to 4 in Table 1 were used.
In No. 6, novolak-type dissolved phenol resin was used and hexamethylenetetramine was used in combination as a curing agent. However, similar characteristics were obtained in the case of a dissolved resol-type resin not requiring a curing agent.

[0044]

The press-fitting material of the present invention has a temperature of 150 ° C to 400 ° C.
The repair material is a press-fitting material at a temperature of, and can maintain the fluidity, cure without foaming, and increase the press-in success rate. Thereby, the temperature rise of the blast furnace iron shell can be suppressed, and the life of the blast furnace can be extended in a safer state.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Matsunaga 1 at 7 Tsukiji, Kisarazu-shi, Chiba Pref. Kurosaki Ceramics Co., Ltd. 1 Nippon Steel Corporation Technology Development Division (72) Inventor Akio Ishii 20-1 Shintomi, Futtsu-shi, Chiba F-term in Nippon Steel Corporation Technology Development Division 4G033 AB23 AB25 BA04 4K015 BA05 BA08 4K051 AA01 AB03 BE03 GA01 LB04 LJ01

Claims (1)

[Claims] Claims 1. A phenolic resin dissolved in an aromatic solvent and coal tar, and a phenolic resin dissolved in an aromatic solvent / coal tar in a weight ratio, relative to 100 parts by weight of one or more refractory aggregates, 80 to 120 parts by weight of a binder mixed at a ratio of 20/80 to 50/50 are added, and the viscosity at the time of construction is 10,000 cps or less, and the viscosity at the start of hardening is 1,000 cps or more. Non-aqueous press-fitting material.