JPH05178674A - Prepared unshaped refractory - Google Patents

Abstract

PURPOSE:To enhance corrosion resistance, spalling resistance and abrasion resistance by adding glass having the specified softening and melting points to refractory materials wherein novolac type phenolic resin is combined with pitch and a mosaiclike carbon bond structure is formed and by specifying the composition. CONSTITUTION:The prepared unshaped refractoried are constituted of 100wt.% refractory aggregate, the following pitch (P) and novolac type phenolic resin (N) of 5-25%, by outer percentage in total amount and glass having 300-400 deg.C softening and melting points of 0.5-10% by outer percentage and can be granulated. In the pitch (P), the temperature difference of melting is within 100 deg.C and the temperature difference of solidification is within 300 deg.C. The weight ratio of P/N is 0.3-12.5. The carbon bond of a mosaic structure is easily obtained by regulating the weight ratio of P/N within the range. When aggregate is heated, separation thereof is prevented by regulating its content to the range. Packing properties, strength and corrosion resistance or the like are made good. Furthermore, separation and settling of aggregate is inhibited by addition of the above-mentioned glass. Generation of laminer peeling is prevented by inhibiting stress generated when aggregate is heated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous refractory having a high hot strength which is excellent in corrosion resistance, spalling resistance and wear resistance, which is used for hot repair of the lining of a steelmaking furnace.

[0002]

2. Description of the Related Art Recently, pitch, phenol resin, etc. have been used as a binder as an amorphous refractory used for hot repair of lining of steelmaking furnace equipment such as converters, ladles, hot metal trucks and vacuum degassing furnaces. The non-aqueous material is used. For example, JP-A-56-26777 and JP-A-56-109874.
This is the material proposed in Japanese Patent Laid-Open No. 57-205381. This non-aqueous amorphous refractory is superior in adhesiveness, corrosion resistance, etc., as compared to the conventional water-mixed form in which water is added and used. Further, it is effective in improving hot filling and workability.

[0003]

However, since these amorphous refractories are used hot, they cannot follow the rapid change in the temperature inside the furnace due to the timing at the time of construction, construction thickness, heating time, etc. It has a drawback that the carbon bond structure formed by pitch or phenol resin is not sufficiently developed. Each of the conventionally proposed materials has its own problems.
In JP-A-56-26777, a pitch and a thermosetting resin are used to improve the adhesive strength due to the pitch and the adhesiveness due to the curing action of the thermosetting resin, but the workability is mainly improved. Yes, it is inferior in hot fluidization filling action. Japanese Unexamined Patent Publication No. 56-109874 provides a repair material that uses a combination of a thermosetting resin and a thermoplastic to generate less smoke and to have a shorter seizure time. However, only the effect of adjusting the heat curing time can be found. In JP-A-57-205381, an organic resin is used as a refractory material containing carbon,
Although the packing density improves the durability, the hot fluidity cannot be obtained.

Further, the materials disclosed in JP-A-56-26777 and JP-A-57-205381 are absolutely required to add water in order to secure adhesiveness, shape retention and workability. However, it has serious drawbacks such as heat spalling of the base material due to moisture. In addition, since these amorphous refractories are heated by the residual heat of the furnace when they are used hot, they are subject to large temperature changes and the amount of use is not constant, so the materials to which they are applied are not constant. Since the thermal effect constantly changes, the conventionally used pitch and phenolic resin do not sufficiently generate the carbon-bonded structure of mosaic structure having high hot strength.

The cause is deeply related to the melting point and solidification temperature of the pitch and the phenol resin. The pitch forms a carbon bond having a flow structure when heated, and the phenol resin on the other hand becomes a carbon bond having a glass structure when heated. Each of these carbon-bonded tissues has merits and demerits.
That is, the flow structure is excellent in spall resistance but low in strength and inferior in wear resistance and corrosion resistance. Although the glass structure has high strength and excellent wear resistance, it has poor spall resistance.

For the pitch or phenol resin used in the conventional amorphous refractory, the kind and the addition amount thereof are determined according to the selection of the characteristics to be utilized and the construction conditions such as furnace heat. Further, when the pitch and the phenol resin are used in combination, the purpose is only to adjust the curing time by utilizing the fast curing property of the phenol resin. The present inventors previously found a method of forming a mosaic carbon bond structure by using a pitch and a novolac type phenol resin in combination, and obtained a considerable effect in improving the durability of the amorphous refractory. ing. It was difficult to adjust the compatibility of pitch and phenol resin in the liquefied state due to unstable construction conditions such as residual heat of the furnace. No attempt was made to improve the characteristics. The inventors of the present invention further conducted research on a method of forming a mosaic carbon bond structure by using pitch and a novolac type phenolic resin in combination, and found that the uniform dispersion of the refractory aggregate and the stress during the heat of the carbonized structure. It turned out that there was a problem with mitigation.

[0007]

The present invention is directed to a refractory aggregate 1
With respect to 00 wt%, the pitch and the novolac type phenol resin having a melting point temperature difference of 100 ° C. and a solidification temperature difference of 300 ° C. or less have a weight ratio of 0.3 to 12.5, and the total weight of the pitch and the novolac type phenol resin is 5 or more. ~ 25 wt% and softening melting point of 300 ~
It is an amorphous refractory characterized by adding 0.5 to 10 wt% of glass at 400 ° C. Also,
This amorphous refractory is characterized by being further granulated.

The pitch used in the present invention has a fixed carbon amount of 4
The pitch used is about 0 to 60 wt%, the melting point is 120 ° C. or less, and the solidification temperature is 450 to 550 ° C., and the melting point is particularly low as the pitch used as the binder of the refractory. The novolac type phenol resin has a number average molecular weight of 200 to 350, a melting point of 70 ° C or lower, and a solidification temperature of 250 to 400 ° C.
It is characterized by a lower melting point and higher solidification temperature than phenolic resins, which are commonly used as binders for refractories.

In the present invention, the pitch and novolac type phenolic resin having these characteristics are used in a weight ratio (P / N).
(Ratio) is 0.3 to 12.5 to easily form a carbon bond structure having a mosaic structure, which has been difficult to form in the past, as an amorphous refractory for hot repair, and It has been found that when the amount is limited to 5 to 25 wt% with respect to the refractory aggregate, the aggregate does not separate when heated and good properties such as filling property, strength and corrosion resistance are obtained.

The present invention further has a softening melting point of 300 to 4
By adding a glass of 00 ° C., it is possible to extend the durability by suppressing the separation and settling of the refractory aggregate and by suppressing the stress generated when heated to prevent the occurrence of delamination. .. When the irregular refractory material of the present invention is granulated, it has the effect of adjusting the melting-solidifying time when it is heated, and by this, it is possible to obtain a construction body with higher filling and excellent filling uniformity.

[0011]

[Function] The process and mechanism of generating a carbon-bonded structure of a mosaic structure having useful properties as a refractory material by using pitch and a phenol resin together have not been clarified at present, but This is probably due to the reason. The novolac type phenol resin used in the present invention starts softening and melting at about 50 ° C.
Solidify at ℃. The pitch starts softening and melting at about 80 ° C and solidifies at about 500 ° C. When the pitch and the novolac type phenol resin coexist in the above ratio, both are first liquefied by being heated. After that, the novolac-type phenol resin begins to solidify, but the solidified portion of the novolak-type phenol resin is still scattered in the entire liquid phase portion of the liquefied pitch. When the temperature further rises, the pitch begins to solidify, but at this time, the novolac-type phenolic resin that started to harden first becomes the core, and it becomes a form that hinders the carbonization of the flow structure of the pitch, and the pitch chain surrounds the core. Ring-shaped rings undergo a condensation reaction to form a three-dimensional mosaic structure.

The carbon bond of the flow structure is likely to cause latent microcracks along the flow structure in the refractory, and a structure with low hot strength is formed as the fracture toughness decreases. The glass-like carbon bond has a high-strength structure, which is a carbon bond peculiar to phenol resin, but it is an amorphous uniform structure, so it has a low spall resistance without crack propagation resistance. ..

On the other hand, since the mosaic structure obtained by the present invention is an aggregate of carbon particles, the fracture toughness of the carbon bond and the crack propagation resistance are improved and the spall resistance is excellent. In addition, it has a high hot strength, excellent corrosion resistance, and excellent wear resistance, and is a useful structure as an amorphous refractory.

What is important in the generation of this mosaic structure is that
This is to sufficiently mix pitch and phenol resin during liquefaction. Therefore, in addition to the liquefaction time (liquefaction temperature range) of the pitch and the phenol resin being similar, it is necessary that both liquefaction times are long and the viscosity at the time of each liquefaction is low in order to improve compatibility. Is.

The pitch and the phenolic resin used for the conventional amorphous refractory are not intended to positively form the carbon bond structure of such a mosaic structure. Regarding the pitch, a pitch having a large fixed carbon amount and a high melting point and a high viscosity is generally used because it is used as a carbon source. Further, phenolic resin is used as a carbon source similar to pitch, and is also used for the purpose of reducing the softening-melting phenomenon of the pitch when heated (giving shape retention) or shortening the repair time. Therefore, the addition of high molecular weight novolac type phenolic resin and hexamethylenetetramine as a curing agent,
Alternatively, it was general to use a resol type phenolic resin having a short liquefaction time. Therefore, in the present invention for the purpose of forming a mosaic structure, it is not possible to use the conventionally commonly used pitch or phenol resin. On the other hand, from the viewpoint of compatibility, it is preferable that the pitch and the novolac type phenol resin have a low melting point, and the lower limit of the melting point is not particularly limited.

The amount of the pitch and the phenol resin used in the present invention is 100% by weight of the refractory aggregate and the weight ratio (P / N ratio) is 0.3 to 12.5. The total amount is 5 to 25 wt%. in this case,
If the total amount is less than 5 wt%, the fixed carbon amount in the refractory becomes too small and the corrosion resistance is poor. If it exceeds 25 wt%, the flowability of the refractory becomes large, the phenomenon of separation of the refractory aggregate becomes remarkable, and the uniformity of the structure as the amorphous refractory deteriorates.

Ratio of pitch and phenolic resin (P / N
When the (ratio) is 12.5 or more, the pitch amount becomes large, and carbon bonds in the flow structure formed by the pitch become remarkable. If it is less than 0.3, the amount of phenol resin will be too much,
Along with the increase in carbon bonds in the glass structure formed by the phenol resin, the fluidity and workability are deteriorated due to the shortening of the liquefaction time, which causes a problem of forming a work body having a low filling property.

Next, glass having a melting point of 300 to 400 ° C. is added to the glass in an amount of 1 to 10% by weight. If it is 1 wt% or less, the generated stress cannot be absorbed, and if it is 10 wt% or more, the liquid phase portion increases when heated, not only the effect of suppressing the settling of the refractory aggregate is not effective, but also the corrosion resistance tends to decrease. Become. The preferable addition amount of glass is 2 to 8 wt% when applied outside.

The melting point of the glass is preferably 300 to 400 ° C. from the viewpoint of preventing the refractory aggregate from settling in combination with pitch or a thermoplastic phenol resin. Thermoplastic phenolic resin begins to harden at about 150 ° C due to heat
Hardens at around 00 ° C. The pitch begins to harden at about 300 ° C and solidifies at about 500 ° C. The glass has a role of softening at about the same time as the hardening temperature of the pitch and controlling the sedimentation of the refractory aggregate with its appropriate viscosity to form a uniform structure. When the melting point is 400 ° C. or higher, the refractory aggregate is hardened before being uniformly filled, so that a cavity is partially formed.

Further, the glass melts hot and fills the space between the refractory aggregate particles to relieve the generated stress, so that it is effective in suppressing the generation of cracks in the refractory structure and preventing peeling. As the glass source, borosilicate glass can be used, but borophosphate glass, which has excellent durability in a higher temperature range, is preferable.

The kind of the refractory aggregate used in the present invention is not particularly limited, and for example, magnesia, dolomite, lime, spinel, chrome ore, alumina, silica, alumina-silica, zircon, zirconia, silicon carbide, or The main material is one kind or two or more kinds selected from brick scraps using these as aggregates. The glass is silicate glass,
Borate glass, borosilicate glass, borophosphate glass, aluminate glass and the like can be used, but borophosphate glass is preferable. If necessary, one or more selected from wetting agents, dispersants, antioxidants, carbon, limestone, metal powder, organic fibers, metallic fibers, inorganic fibers and the like may be added.

The amorphous refractory material obtained by the present invention has an effect as a repair material even if it is used as it is, but granulation can be expected to further improve the durability. The purpose of granulating the amorphous refractory obtained in the present invention,
To regulate the transfer of furnace heat to the pitch and resin.
In the case of non-granulation, since the furnace heat is directly transferred to the pitch and the resin, the furnace heat is quickly transferred to the pitch and the resin. As a result, by shortening the time of the pitch and the resin in the liquid state, the compatibility of the pitch and the resin decreases,
Physical properties may be deteriorated due to the less generation of the mosaic structure.

On the other hand, in the case of granulation, the heat transfer to the inside of the granulation is slower than that in the non-granulation, and the compatibility of the pitch and the resin is increased by extending the liquid time of the pitch and the resin. It is effective in promoting the generation of the mosaic structure and improving the durability by improving the physical properties. Furthermore, the solidification time can be adjusted. As a method of granulating, for example, an appropriate amount of a non-aqueous binder is added to the entire mixture, the mixture is pressure-molded, and then granulated by pulverization. Further, an appropriate amount of a non-aqueous binder may be added to the entire mixture and granulated by a rolling method or the like. The non-aqueous binder used for this granulation is not limited to pitch and phenol resin, but furan resin, phenol resin, epoxy resin, paraffin and the like can be used.

[0024]

EXAMPLES Examples of the present invention and comparative examples are shown below.
Table 1 shows the quality values of the pitch and phenol resin used in each example. Table 2 shows the quality values of the borophosphate glass used in each example.

[0025]

[Table 1] * Among phenolic resins, and are resins within the range used in the examples of the present invention. Phenolic resin is the resin used in the comparative example. * The resin in the pitch is within the range used in the examples of the present invention. Pitch is the pitch used in the comparative example.

[0026]

[Table 2]

[Physical property measuring method] <1> Fluidity 7 g of a material of 800 g is air rammed.
A 70 square sample is prepared by hitting 50 times with a pressure of kg / cm ² . This sample was placed in an electric furnace at 700 ° C., softened to melted by heat, and spread to a large extent.
It was divided into three stages, medium and small.

The following physical properties were measured as follows.
125φ with the lower part sealed and the upper part opened in a predetermined furnace
A metal pipe of × 750 is set, and the metal pipe is heated to 800 to 900 ° C. Thereafter, a total of 20 kg of amorphous refractory material, which is divided into 1 kg portions, is sequentially charged into the pipe from the top of the pipe. After the amorphous refractory is cured, a predetermined sample for measuring physical properties is cut out.

<2> Fillability The apparent porosities of the middle part and the upper part of the amorphous refractory material were measured. The smaller the value is, the better the filling property is, and the smaller the difference between the middle part and the upper part is, the better the filling uniformity of the construction product is.

<3> Generation ratio of upper porous layer: The refractory aggregates are settled by the melting of the pitch and the resin due to the heat,
The refractory aggregate was diluted and the size of the porous layer formed on the upper part of the construction body was measured. The size of the porous layer is indicated by the ratio in the height direction of the construction body. The larger the value, the greater the generation of the porous layer.

<4> Spoll resistance A sample of 40 □ × 120 was cut out from the middle part and cut into 16
After being immersed in molten steel at 00 to 1650 ° C. for 3 minutes, it is air cooled for 10 minutes. This is defined as 1 cycle, and after 5 cycles, the central part in the length direction is cut, and the degree of cracks in the cut surface is large, medium,
It was divided into three small stages.

<5> Corrosion Resistance A predetermined sample was cut out from the middle portion and subjected to an erosion test by a rotation method at a weight ratio of steel 80: slag 20 at 1650 ° C. as a solvent. As a comparison of the erosion tests, a comparative example, No. 3, in Table 4 corresponding to a non-aqueous baking repair material usually used in a converter is used. The melt loss size of No. 7 was set to 100, and the ratio was shown. The smaller the ratio, the higher the corrosion resistance.

<6> Hot Bending Strength A test piece cut out to a thickness of 20 × width of 30 × length of 120 mm was heated in a coke breeze at 1400 ° C. for 1 hour and then 1
The bending strength with a push rod was measured on a span of 100 mm with the temperature kept at 400 ° C.

<7> Generated stress 40 × 4 from the middle part
Cut out a sample of 0 × 120 mm and 800 ° C × 2
The test stress after heat treatment for Hr was subjected to one-side restraint to measure the hot stress generated, and the maximum stress is shown in Table 4 as Comparative Example No. 1
The ratio is set to 00. The smaller the ratio, the smaller the generated stress. Note that the blank columns are those that were not measured.

Tables 3 to 7 show compounding compositions and test results of each example.

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

[Table 5]

[0039]

[Table 6]

[0040]

[Table 7]

[0041]

The mosaic carbon bond structure obtained in the present invention is an aggregate of carbon particles, and therefore exhibits an excellent spall resistance and improved fracture toughness and crack propagation resistance of carbon bond. High hot strength and high corrosion resistance,
A structure excellent in high wear resistance can be arbitrarily obtained. Further, the stress generated during hot is reduced to suppress the generation of cracks in the structure, the delamination is eliminated, and the structure having high durability is formed.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 13, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Next, glass having a melting point of 300 to 400 ° C. is added 0.5 to 10 % by weight . 0.5 w
When t% or less, the generated stress cannot be absorbed and 10w
If it is t% or more, the liquid phase portion when heated is large, and not only the effect of suppressing the settling of the refractory aggregate is not exerted, but also the corrosion resistance tends to decrease. The preferred amount of glass added is 1 to 8 w
t%.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinobu Kambe 1-3-1 Niihama, Arai-cho, Takasago-shi, Hyogo Within Harima Ceramics Co., Ltd. (72) Iyoyuki Hayashida 1-3-3 Niihama, Arai-cho, Takasago-shi, Hyogo Prefecture 1 Harima Ceramics Co., Ltd.

Claims (2)

[Claims] 1. A pitch and a novolac type phenol resin having a melting point temperature difference of 100 ° C. and a solidification temperature difference of 300 ° C. with respect to 100 wt% of a refractory aggregate, and the weight ratio of both is 0.3 to 12. 5, 5 to 25 wt.
%, And 0.5 to 10 wt% of glass having a softening melting point of 300 to 400 ° C. is externally added to the amorphous refractory. 2. An irregular refractory material obtained by granulating the irregular refractory material according to claim 1.