JPH0541594B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a self-flowing monolithic refractory material used for repair and filling in various high-temperature kilns. [Conventional technology] Hot repair materials are widely used in converters, electric furnaces, AOD furnaces, ladles, etc. to fill in cavities caused by damage to lining refractories by utilizing the fluidity of the material. . This material is generally made by adding coal tar pitch to basic aggregate and kneading it under heat, or in some cases adding creosote etc. and kneading it at room temperature to form plastic lumps, solids, etc. It is in the form of powder, powder with granular pitch added, etc. Coal tar has a high residual carbon content after heating, forms a good carbon bond, and is relatively inexpensive, so it has been widely used as a binder for baking materials. However, coal tar pitch contains harmful substances in its volatile gases and generates intense smoke during hot repairs, creating a poor working environment. Coal tar pitch is approximately 500℃
As described above, volatile matter is lost through the decomposition and polymerization reactions, and the material is carbonized, but since it is a mixture of organic substances with various compositions, the reaction proceeds in a complicated manner. Therefore, it takes a long time to carbonize the coal tar pitch at a temperature of about 500 to 600°C, that is, to harden the baking material. Baking materials are generally put into a furnace at high temperatures, and the natural flow of the material itself fills in the dents in the lining caused by damage, making it effective as a repair material, so good fluidity is required. be done. Therefore, if the amount of coal tar added is increased in order to obtain good fluidity, even if fluidity is obtained, the disadvantage is that the time required for curing becomes longer. Various attempts have been proposed to improve the drawbacks of baking materials using these coal tar binders. For example, instead of coal tar, there is a mixture (Japanese Patent Publication No. 62-28112) in which a phenolic resin or melamine resin and powdered carbon are added to a thermoplastic selected from aromatic petroleum resin, petroleum pitch, and heavy oil.
Petroleum-based thermoplastics are carbonized and have poor strength after solidification, making them insufficient for materials such as converter charging walls that require wear resistance.
In addition, novolak type phenolic resin is added to the basic aggregate, and the mixture is heated and kneaded to form a lumpy solid material.
17072), when the temperature of the furnace body is high, the surface of the lump starts to harden and carbonize before the inside of the lump melts and softens, and the entire lump often does not flow, making it difficult to obtain a satisfactory repair effect. In addition, repair materials are prepared by adding paraffin to basic refractory aggregate, bituminous substances such as coal tar, and thermosetting resins such as phenolic resin, and granulating them into small lumps (Japanese Patent Laid-Open No. 63
-74973) can be kneaded by low-temperature heating by using paraffin, which has the advantage of preventing smoke generation during kneading, but when placed in a high-temperature furnace, the surface of the lumps hardens quickly, and each lump The disadvantage is that it is difficult to melt and soften the material and integrate it into the roof tile. Furthermore, a repair material made by adding and kneading granular coal tar pitch, a granular or liquid low molecular weight thermoplastic resin, and an organic solvent to a basic refractory aggregate (Japanese Patent Application Laid-Open No. 61-242962) has poor natural flowability. The problem is that it becomes a fluid and fills the recesses. Furthermore, a material obtained by kneading a fireproof material and a powdered resin with a polyhydric alcohol (Japanese Patent Application Laid-Open No. 156081/1981) does not flow at all, especially when a thermosetting resin is used. [Problems to be Solved by the Invention] As described above, coal tar pitch takes a long time to harden, so it remains in a softened state due to heating for a considerable period of time and exhibits fluidity, but there is a problem with the generation of harmful substances and Repairs take a long time. On the other hand, with resin binding materials, the surface of the baking material begins to harden before the inside of the baking material is heated and softened, and the entire material cannot flow, making it difficult to obtain an integrated construction body. In order to solve these problems, we used phenolic resin as a binder that can form a good carbon bond, and it also has excellent hot fluidity that could not be obtained with conventional repair materials using resin, and is strongly integrated. As a result of various studies in order to obtain a monolithic refractory material that provides a construction body with improved construction properties, the present invention was achieved. [Means for Solving the Problems] That is, the present invention provides a refractory aggregate with particle size adjustment of 80~
90 parts by weight and 10 to 10 parts of liquid novolak type phenolic resin
An organic separation inhibitor that has a melting point or softening point of 50°C or higher and is insoluble or sparingly soluble in organic solvents at room temperature is added and kneaded to a mixture consisting of 20 parts by weight to give a flow value of 125 to 180 mm. The gist is a monolithic refractory material with self-flowing properties. The monolithic refractory material of the present invention is not a plastic, solid or powder-like material as in the past, but is a slurry-like material with self-flowing properties, and does not soften and flow due to furnace heat, but flows even at room temperature. have sex. Therefore, when it is put into a hot furnace, it shows good fluidity even at high temperatures, fills the recesses caused by damage to the refractory lining wall in the furnace, and forms a dense and integrated structure with a strong carbon bond. Forms a refractory layer and enables effective repair. The binder used in the monolithic refractory material of the present invention is
A known liquid novolak type phenolic resin is used as the binder for the amorphous refractory material. Novolak type phenolic resin is originally solid at room temperature, and there are powdered and granular forms, but in the present invention, in order to provide self-flowing properties at room temperature, liquid novolak type phenolic resin containing various organic solvents is used. It will be done. Novolac type phenolic resins, which are the base of liquid novolac type phenolic resins, have various molecular weights depending on their degree of polymerization. Although the molecular weight is not particularly limited, in general, higher molecular weight resins have higher viscosity when liquefied by adding an organic solvent, and the tendency is to increase the amount of liquid resin mixed in order to provide self-flowing properties at room temperature. Therefore, it cannot be said that it is economical. Further, higher molecular weight resins tend to polymerize more quickly when exposed to high temperatures, harden more quickly, and have lower hot fluidity, which is not preferable. Simply adding fluidity to the refractory aggregate can be easily achieved by mixing a large amount of liquid novolak type phenolic resin to the refractory aggregate, but the refractory aggregate may settle and separate due to vibrations during storage or transportation by truck, etc. , it is difficult to put it into practice. The most important point in the monolithic refractory material of the present invention is to achieve both good fluidity and prevention of settling and separation of aggregate. Of course, the quality characteristics of the hot-applied cured body, ie, the filling density, strength, etc., must be satisfactory. Liquid novolak type phenolic resin is composed of a resin component and an organic solvent, and there are various commercially available products with different viscosities in the liquid state depending on the ratio of the resin and the type of solvent. In order to give fluidity to the refractory material, by using a low viscosity liquid novolak type phenolic resin, a small amount of mixing is required, whereas when using a high viscosity liquid novolak type phenolic resin, it is necessary to increase the mixing amount relatively. There is. Therefore, from an economic point of view, it is more effective to use a small amount of low viscosity resin. Furthermore, the viscosity of liquid novolac type phenolic resins varies depending on the temperature even if the resin is the same. At low temperatures, the viscosity is high, and at high temperatures, the viscosity decreases. This is a large enough change to affect the self-flowing properties of the formulation due to changes in temperature. In the case of a low viscosity, if a resin with a viscosity of less than about 10 poise is used, it is not preferable because the fluidity changes over time after the compound is kneaded and left to stand. Although the reason for this is not clear, it is thought that there may be an influence such as penetration of liquid into the aggregate during storage. On the other hand, even if the viscosity is high and exceeds 400 poise, there is no practical problem, but the amount of liquid resin required to provide self-flowing properties increases, which is not economical. Therefore, the viscosity of liquid novolak phenolic resins varies from approximately 10 poise to changes in temperature from the time the formulation is manufactured until it is used.
It is preferable to adjust it within the range of 400 poise. Note that, for example, the same effect can be obtained by using a high-viscosity liquid resin and adding another organic solvent to adjust the viscosity of the liquid component so that it falls within the above range. Regarding the ratio of resin content to organic solvent in liquid novolac type phenolic resin, most of the ordinary liquid novolac type phenolic resins have a resin content of about 50%, but in terms of strength due to the formation of carbon bonds in the cured product, Approximately 15% resin content
Anything above can be used. The organic solvent contained in the liquid novolak type phenolic resin is not particularly limited, as long as it dissolves the phenolic resin, and generally includes alcohols such as ethanol, cellosolve, ethylene glycol, triethylene glycol, and propylene glycol, and acetone. , ketones such as methyl ethyl ketone, furfural, and the like may be used alone or in combination, and are determined in consideration of safety aspects such as the above-mentioned viscosity and flash point. Next, an experiment was conducted to determine the minimum amount of liquid novolak type phenolic resin required. FIG. 1 is a diagram showing the relationship between the amount of liquid novolak type phenolic resin mixed and the fluidity in hot conditions. For the refractory material, we use magnesia clinker whose particle size has been adjusted, and liquid novolac type phenolic resin with various viscosities is added so that the self-fluidity of the slurry material after kneading is 140 to 145 mm in flow value at room temperature. Samples were prepared by adjusting the amount of resin. 1 kg of this sample was dropped onto a flat plate made of castable refractory material in a test furnace heated to 1000°C, and the measured value of the diameter expanded by the flow of the sample after standing was plotted. As is clear from this figure, when the liquid novolak type phenolic resin is less than 10%, the hot fluidity rapidly decreases even though the self-fluidity at room temperature is approximately the same. On the other hand, when the amount of liquid novolak type phenolic resin is large, no particular problem occurs, but even if the amount exceeds 20%, the effect of improving hot fluidity is small and it is uneconomical. Therefore, the amount of liquid novolak type phenolic resin mixed is preferably 10 to 20 parts by weight. In this way, by mixing refractory aggregate and liquid novolac type phenolic resin, it is possible to obtain a blended material that forms satisfactory carbon bonds after heating and has self-flowing properties at room temperature, but there is another important problem. Generally, the refractory aggregate and the liquid novolak type phenolic resin have a property of being difficult to wet, so the refractory aggregate settles and separates due to vibrations during storage or especially during transportation. When the refractory aggregate settles and separates, the lower aggregate sedimentation layer is hard and shows no fluidity, leaving only the upper liquid resin layer containing fine powder fluid. Even if the material separated in this way is placed in a high-temperature kiln, the sedimentary layer remains a lump and cannot be deformed, and only the upper liquid resin layer flows, making it impossible to obtain a satisfactory hardened structure. In order to solve this problem, we have developed an organic separation inhibitor that has a melting point or softening point of 50° C. or higher and is insoluble or poorly soluble in organic solvents at room temperature. Organic separation inhibitors with a melting point or softening point of 50°C or higher include polyolefins such as polyethylene and polypropylene, methane group hydrocarbons such as paraffin, fatty acids such as stearic acid, their salts and esters, oils and fats and their salts and esters. , various synthetic polymer compounds, etc., and the composition thereof is not particularly limited. The organic separation inhibitor is solid at room temperature like the refractory aggregate, and by adding a small amount of it, the amount of liquid resin appears to be insufficient, and the sedimentation and separation of the refractory aggregate can be virtually ignored. can be suppressed. Therefore, the organic separation preventive agent used in the present invention must at least maintain a solid state at the temperature from which the compound is manufactured until it is used, and should have a melting point or softening point of 50°C or higher, taking into account the temperature rise during transportation. It is necessary to have The organic separation preventing agent is preferably in the form of a powder, scale, fiber, or ribbon with a large surface area.
Furthermore, it is essential that the organic separation inhibitor is insoluble or poorly soluble at room temperature in the organic solvent contained in the liquid novolac type phenolic resin used in the present invention, and preferably at a relatively low temperature, e.g. It is preferable that the liquid becomes a low viscosity liquid at 150°C or lower. This is because the refractory aggregate, which is solid at room temperature, prevents sedimentation and separation, and when heated, becomes liquefied at a relatively low temperature, promoting fluidity in hot conditions. Furthermore, it is preferable that the specific gravity of the organic separation inhibitor is the same as or smaller than the specific gravity of the liquid novolak type phenolic resin. When the specific gravity is lower than that of the liquid resin, buoyancy acts on the organic separation preventive agent, which is highly effective in preventing settling of the refractory aggregate, which has a high specific gravity. The amount of the organic segregation inhibitor to be added may be small, and is usually 0.1 to 5% by weight based on the blend of fireproof aggregate and liquid novolak type phenolic resin. 0.1% by weight
If the amount is less than 5% by weight, the effect will be small in the case of formulations with a large amount of liquid resin, and since a sufficient effect can be seen with addition of 5% by weight or less, there is no point in adding more than 5% by weight. On the contrary, if it is added in excess, it may reduce the self-flowability and hot fluidity of the entire mixture. The optimum amount of the organic separation preventive agent to be added is determined by the particle size structure of the refractory aggregate, the viscosity and mixing amount of the liquid novolak type phenolic resin, the form of the organic separation preventive agent itself, etc. The amorphous refractory material of the present invention, which is obtained by kneading the refractory aggregate obtained as described above, a liquid novolak type phenolic resin, and an organic separation preventive agent, has good hot fluidity and anti-sedimentation properties of the refractory aggregate. Whether or not the self-flowing property shown was within an appropriate range was determined by the flow value according to the flow test method of JIS R-2521. The flow test method is originally a method for evaluating the fluidity of alumina cement, but it is also widely used to evaluate the fluidity of castable refractories. Therefore, the monolithic refractory material of the present invention can be directly applied to the adjustment of self-fluidity. Furthermore, it has been found that when the flow value is large, sedimentation and separation of the refractory aggregate occurs in some cases, so it is necessary to specify the flow value within a certain range. That is, in Fig. 2, the relationship between the flow value, hot fluidity, and separation of the refractory aggregate was measured for a sample obtained by adding and kneading an organic separation inhibitor to a compound consisting of magnesia clinker and liquid novolak type phenolic resin. . Samples were prepared by changing the mixing amount of liquid novolak type phenolic resins with various viscosities, adding appropriate amounts of various organic separation inhibitors, and kneading them. After leaving the sample at room temperature for 3 days after preparation,
The test was conducted at 1000°C in the same manner as determined in FIG. 1 above. Regarding the separation depth of refractory aggregate, immediately after preparing the sample, insert the sample into a cylindrical container so that the height is 100 mm, and after applying vibration for 30 minutes, fine powder and liquid that do not contain refractory aggregate particles are separated. The depth of the upper layer consisting of If the flow value is less than 125 mm, the fluidity in hot conditions will decrease significantly, and if it exceeds 180 mm, the liquid resin will flow preferentially due to the effect of separation of the refractory aggregate, causing overall flow and expansion. tends to decrease. In terms of separation depth, when the flow value exceeds 180 mm, the sedimentation of refractory aggregate particles increases rapidly after vibration is applied. As described above, when the flow value is less than 125 mm, the self-flowability is too small, and the hot fluidity is also insufficient. On the other hand, if the flow value exceeds 180 mm, sedimentation of the refractory aggregate may be observed when vibration is applied even if an organic separation inhibitor is added, so the self-flowing monolithic refractory material of the present invention exhibits its performance. The flow value must be in the range 125-180mm. However, since the viscosity of the liquid novolak type phenolic resin changes depending on the temperature, even if the mixture has the same blending ratio, the flow value will differ depending on the temperature. Therefore, it is difficult to define the self-flowing monolithic refractory material of the present invention only by the blending ratio. However, the object of the present invention can be achieved if the flow value is specified in a composition obtained by adding and kneading an organic separation inhibitor to a mixture consisting of at least 80 to 90 parts of refractory aggregate and 10 to 20 parts of liquid novolak type phenolic resin. Provides hot fluidity and prevention of sedimentation and separation of refractory aggregates. The refractory aggregate used in the self-flowing monolithic refractory material of the present invention is preferably a basic aggregate such as magnesia when used in a smelting furnace, etc., and a basic aggregate such as silica, zircon, or alumina when used in a hot metal container etc. Acidic or neutral aggregates may be selected, but are not particularly limited. The particle size of the refractory aggregate is preferably adjusted to about 20 to 60% fine powder of 0.3 mm or less, which is used for ordinary unshaped refractories. It is also possible to add a small amount of ultrafine powder such as silica, alumina, or zircon to improve the structure after hardening, and carbonaceous materials such as graphite, carbon black, or solid pitch can also be added to reinforce the carbon bond. , mesophase carbon, etc. may be added. It is also possible to add a small amount of surfactant for the purpose of improving fluidity. [Example] For the monolithic refractory material (Example) of the present invention, comparative examples, and conventional examples, the hot flow performance, sedimentation separation of refractory aggregate, and physical properties of hot cast products are listed in the attached table. In addition, each physical property etc. depended on the following test method. The flow value was measured by the method according to JIS R2521, the separation depth was measured by the method shown in the explanation of Figure 2 above, and the hot fluidity was measured after each sample was left for 7 days after preparation.
The flow end time is determined by visually observing how the dropped sample expands in a circular shape as it flows, and determining the flow end time using the method shown in the explanation of Figure 1 above. The time is measured, the state of smoke generation is visually checked, and the physical properties of the hot cast product are measured in a small furnace with internal dimensions of 200×
A 125 x 90 mm refractory pod was set and heated to 1200℃.
Turn off the burner until the internal temperature of the pod reaches
When the sample was cooled to 1000℃, a 6 kg sample was put into it.
Leave it to stand, cool it to room temperature, and then cut it to prepare a sample. Measure the porosity and bending strength of this sample using standard methods.

〔Effect of the invention〕

The self-flowing monolithic refractory material of the present invention exhibits excellent fluidity with almost no sedimentation and separation of the refractory aggregate due to the addition of an organic separation inhibitor. Therefore, it brings about various benefits. For example, it can be packed in a flexible container bag of about 1 ton, transported and stored as it is, and then put into the furnace, making the work easier as it eliminates the need for small packages of 5 to 10 kg, which have been used in the past. In addition, conventionally fluid materials were kneaded in a mixer etc. at the site of use, but the monolithic refractory material of the present invention can be kneaded at the manufacturing factory, so it requires fluidity for construction at room temperature. It can also be applied to materials such as materials for filling gaps. In addition, the product of the present invention is used for repairing a converter with a capacity of 250 tons, and the product is used for repairing a converter with a capacity of 250 tons.
Immediately after putting it into a flexible container, it becomes flat due to its good fluidity, hardens in about 20 minutes, and is ready for use. Conventional pitch material requires a long time of about 1 and a half hours to use, and the lifespan was 5 to 6 charges, but the product of the present invention has a lifespan of 10
A significant improvement of ~15 charges.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the mixing amount of liquid novolak type phenolic resin and hot fluidity, Figure 2 is a graph showing the relationship between flow value and hot fluidity, and Figure 3 is a graph showing the relationship between Example 2 and the conventional example. 4 is a graph showing the curing time at each temperature.

Claims (1)

[Scope of Claims] 1. A blend consisting of 80 to 90 parts by weight of refractory aggregate whose particle size has been adjusted and 10 to 20 parts by weight of liquid novolak type phenolic resin, which has a melting point or softening point of 50°C or higher, and an organic solvent. An organic separation inhibitor that is insoluble or poorly soluble at room temperature is added and kneaded to adjust the flow value.
A monolithic refractory material with self-flowing properties of 125 to 180 mm. 2. The organic separation inhibitor is at least one of polyolefins such as polyethylene and polypropylene, methane group hydrocarbons such as paraffin, fatty acids such as stearic acid, salts or esters thereof, and fats and oils and salts or esters thereof. Monolithic refractory material.