JP2018158870A - Mud material for blocking blast furnace tap pore - Google Patents

Abstract

The present invention provides a mud material using a novolac-type phenolic resin as an organic binder capable of exhibiting adhesive strength at an early stage and simultaneously suppressing a change in viscosity over time. SOLUTION: A novolac resin containing a refractory aggregate, an organic binder and a curing agent, wherein the organic binder is in the range of a weight average molecular weight of 3000 to 10,000, the curing agent is hexamethylenetetramine, and hexamethylenetetramine. The blending amount of the novolac resin is 0.5 to 3.0% by mass with respect to the novolac resin, and the blending amount of the novolac resin is 10 to 30% with respect to 100% by mass of the refractory aggregate. % Blast furnace outlet hole closing mud material. The refractory aggregate is composed of 5 to 75% by mass of an oxide refractory material, 3 to 25% by mass of a carbonaceous material, 5 to 50% by mass of a silicon carbide material and 5 to 40% by mass of a silicon nitride material. Mud material for hole closure. [Selection figure] None

Description

  The present invention relates to a mud material for closing a blast furnace outlet hole used for closing an outlet hole of a blast furnace.

  Blast furnace tap hole closing mud material (hereinafter referred to as “mud material”) is used to close the tap hole, which is the path for discharging hot metal and molten slag from the blast furnace to the end of the furnace. Refractory. Closing the tap hole is performed by press-fitting a mud material into the tap hole that is being put out by a press-fitting machine called a mud gun to close the tap hole, thereby stopping the tapping.

  The mud material used to close the tap hole is usually a mixture of refractory aggregates such as oxide refractory raw materials, carbonaceous raw materials, silicon carbide raw materials, silicon nitride raw materials and the like, and then a large amount of organic binder. Is added and kneaded. As the organic binder added to the mud material, coal tar and phenol resin are generally used. However, the coal tar mud material has a problem in that after filling the tap hole, smoke or a strange odor is generated by heating from the furnace wall, and the working environment in front of the furnace is deteriorated. For this reason, the use of coal tar mud materials requires powerful dust collection equipment, etc., and it is difficult to use coal tar mud materials in blast furnaces where these facilities are not sufficient, and there is no risk of fumes or off-flavors. It is common to use a phenolic resin mud material.

  Further, after the mud gun is filled with the mud material from the mud gun, the mud gun and the tap hole are maintained in a state where they are pressed for a certain time, and this time is referred to as a pressing time. The mud material filled within the pressure bonding time develops strength by heating. Here, the developed strength is the strength between the filled mud material and the taphole furnace wall and is referred to as adhesive strength. In the blast furnace, the operation is called alternate brewing, where the brewing and closing are alternately performed using two brewing holes, and the crimping time is usually about 20 to 60 minutes. Strength is fully expressed. On the other hand, in an operation called continuous brewing that repeats brewing and closing continuously using one brewing hole, the crimping time can often be taken only about 5 to 10 minutes, and the adhesive strength of the mud material is increased. The heating time for making it express will become short. Also, if the mud gun is detached from the tap hole before sufficient adhesive strength is developed, it is called natural tapping where the mud material filled in the tap hole is blown out of the tap hole by the pressure in the furnace. Trouble may occur. For this reason, the property that the adhesive strength is developed at an early stage has been demanded for the mud material used under conditions where the crimping time is short, such as a continuous tapping operation.

  Further, in order to fill the mud material in a good state into the tap hole, it is necessary to adjust the viscosity appropriately at the time of manufacturing the mud material. However, even if the viscosity is adjusted during production, the viscosity of the mud material may increase over time. If the viscosity of the mud material increases, the mud gun's press-fitting capacity will be exceeded during filling, and no more mud material can be filled, making it impossible to fill the furnace with the specified amount of mud material. There is sex. In such a case, there is a possibility that the bottom of the taphole will be lowered or the bottom temperature of the furnace will be increased to hinder the formation of the deposition base in the furnace, causing a great deal of damage such as wind reduction and production reduction. . The period until the manufactured mud material is used on the actual machine varies, but overseas export products have a long period of time from manufacture to use on the actual machine, and can be used up to about 3 months after manufacture. It has been necessary to maintain the state, and there has been a demand for a mud material having a small viscosity change with time.

  In the phenolic resin mud material that does not cause deterioration of the work environment such as smoke and nasty smell, in order to prevent troubles such as natural sag, the adhesive strength is developed early, and the spill hole can be satisfactorily filled In order to maintain the viscosity, there has been a demand for a mud material having a small change in viscosity with time. For example, Patent Document 1 discloses a mud material containing a refractory aggregate, a dispersant, and an organic binder, wherein the dispersant is a polyester acid amide amine salt and / or a polyether ester acid amine salt. It is possible to reduce the amount of organic binder added by using a polyester acid amide amine salt and / or a polyether ester acid amine salt as a dispersant. As a result, it is included in the mud material. Volatile components are reduced, and strength can be expressed early. However, with the mud material disclosed in Patent Document 1, the effect of promoting the strength development obtained is extremely small, and it has not been possible to completely solve troubles such as natural sag.

  In addition, in the phenolic resin mud material, the phenolic resin added as the organic binder is changed to a resol type phenolic resin, or hexamethylenetetramine as a curing agent for the novolac type phenolic resin in order to develop the adhesive strength at an early stage. It is generally known to add. However, since the resol type phenol resin itself increases in viscosity over time, the mud material using the resol type phenol resin as an organic binder has a problem that the viscosity increases over time. In addition, the novolac resin alone does not increase in viscosity over time, but if a curing agent such as hexamethylenetetramine is added, the viscosity increases over time, so a curing agent was added. A mud material using a novolac type phenolic resin as an organic binder has a problem that the viscosity increases with time.

  In addition, there is also a mud material using a novolac type phenol resin to which a curing agent such as hexamethylenetetramine is not added as an organic binder in order to suppress a change in the viscosity of the mud material with time. This is because the viscosity of a novolak type phenol resin alone does not increase with time as described above. However, novolac type phenolic resin with no hardener added takes a long time to develop adhesive strength, and there is no problem in alternating brewing operations that can secure a long crimping time. There is a possibility that troubles such as natural production may occur during the production operation. Thus, in a mud material using a novolac type phenol resin as an organic binder, it was impossible to achieve both early expression of adhesive strength and suppression of change in viscosity over time with or without the addition of a curing agent such as hexamethylenetetramine.

JP 2013-63883 A

  Accordingly, an object of the present invention is to provide a mud material using a novolac-type phenol resin as an organic binder that can develop adhesive strength at an early stage and can suppress a change in viscosity over time.

  As described above, by adding a curing agent such as hexamethylenetetramine to a novolac-type phenol resin, it is possible to develop adhesive strength at an early stage, but on the other hand, there is a problem that the viscosity increases with time. is there. Further, when no curing agent such as hexamethylenetetramine is added, there is a problem that the time until the adhesive strength is developed becomes long although the change in viscosity with time can be suppressed. As a result of various studies to solve these two problems at the same time, when the amount of addition of hexamethylenetetramine as a curing agent is the same, the weight average molecular weight of 500 to 500 normally used as an organic binder for mud materials is usually used. It was found that when a novolac type phenol resin having a weight average molecular weight of about 3000 to 10,000 is used, the adhesive strength is developed early compared to about 2500 novolak type phenol resin. Further, it was found that when novolac type phenol resin having the same weight average molecular weight is used, the change in viscosity of the mud material with time decreases as the amount of hexamethylenetetramine added decreases. In addition, a mud material prepared by adding a small amount of hexamethylenetetramine to a novolac type phenol resin having a weight average molecular weight of about 3000 to 10000, adjusted to have the same expression time of adhesive strength, and a novolak having a weight average molecular weight of about 500 to 2500 As a result of preparing a mud material in which a large amount of hexamethylenetetramine was added to a type phenolic resin and comparing changes in viscosity with time, it was found that the former had less change with time in viscosity. From this result, a novolak type phenol resin having a weight average molecular weight of about 3000 to 10,000 is used as an organic binder, and the blending amount of hexamethylenetetramine as a curing agent is small, specifically, with respect to the blending amount of the novolak type phenol resin. It has been found that by using 0.5 to 3.0% by mass as an outer coating, a mud material can be obtained in which adhesive strength is developed early and the change in viscosity of the mud material over time can be suppressed.

  The “weight average molecular weight of the novolak type phenol resin (synonymous with mass average molecular weight)” described in the present specification is measured by a gel permeation chromatography method (GPC method).

This result is thought to be due to the following mechanism.
That is, the novolak-type phenol resin is an aggregate of chain molecules, but a large weight average molecular weight indicates that the chain molecules are long. The longer the chain molecule, the more complicated the chain molecules are entangled with each other. Therefore, it is considered that the strength increases even if a reaction occurs in part, that is, the adhesive strength is expressed early. On the other hand, when the weight average molecular weight is small, the chain molecules are short and the chain molecules are less entangled with each other.

  In addition, by reducing the amount of hexamethylenetetramine added, the change in viscosity over time can be suppressed. By reducing the opportunity for contact between the hexamethylenetetramine and the chain molecules constituting the novolak phenol resin, condensation can be achieved. This is thought to be because the reaction rate has decreased. In addition, the amount of hexamethylenetetramine added to a refractory using a novolac type phenolic resin is about 10% by mass with respect to a novolac type resin that is usually added. As described above, the amount of hexamethylenetetramine added to the novolak type phenolic resin is very small at 0.5 to 3.0% by mass, so that the change in viscosity of the mud material over time can be suppressed. it is conceivable that.

  That is, the present invention relates to a mud material containing a refractory aggregate, an organic binder and a curing agent, wherein the organic binder is a novolak type phenol resin having a weight average molecular weight of 3000 to 10,000, and the curing agent is hexagonal. It is methylenetetramine, and it is a mud material characterized in that the blending amount of hexamethylenetetramine is in the range of 0.5 to 3.0% by mass with respect to the novolac type phenol resin.

  In addition, the mud material of the present invention is characterized in that the blending amount of the novolac type phenolic resin is in the range of 10 to 30% by mass on the basis of 100% by mass of the refractory aggregate.

  Further, in the mud material of the present invention, the refractory aggregate has an oxide refractory raw material of 5 to 75 mass%, a carbonaceous raw material of 3 to 25 mass%, a silicon carbide raw material of 5 to 50 mass%, and a silicon nitride raw material of 5 to 40. It has a blending ratio of mass%.

  According to the present invention, the novolac type phenol resin having a weight average molecular weight of 3000 to 10000 is used, and the amount of hexamethylenetetramine compounded as a curing agent is made small so that the adhesive strength of the mud material is developed early. At the same time, it is possible to suppress a change in viscosity with time, and it is possible to provide a mud material that can perform good blocking.

The mud material of the present invention contains a refractory aggregate, an organic binder and a curing agent.
First, the organic binder used for the mud material of the present invention is a novolak type phenol resin having an average weight molecular weight of 3000 to 10000, preferably 4000 to 8000. When the average molecular weight of the novolak type phenol resin is less than 3000, it is necessary to increase the blending amount of hexamethylenetetramine in order to develop the adhesive strength of the mud material at an early stage. Since it will become large, it is not preferable. Further, when the weight average molecular weight of the novolac type phenol resin is more than 10,000, the viscosity of the novolac type phenol resin is too high, and therefore a mud material having an appropriate viscosity cannot be obtained.

  The blending amount of the novolac type phenolic resin can be adjusted as appropriate according to the use situation as long as it is within the range of the organic binder amount of the ordinary mud material, and it can be applied to 100% by mass of the fireproof aggregate described later. It exists in the range of 10-30 mass%, Preferably it exists in the range of 12-25 mass%. Here, when the blending amount of the novolac type phenolic resin is less than 10% by mass with respect to 100% by mass of the refractory aggregate, the plasticity of the kneaded clay required for filling the mud material into the tap hole is sufficient. On the other hand, if it exceeds 30% by mass, the mud material structure becomes porous and the corrosion resistance decreases, which is not preferable.

  Further, hexamethylenetetramine is blended as a curing agent for the novolak type phenol resin. The compounding amount of hexamethylenetetramine is in the range of 0.5 to 3.0% by mass, preferably in the range of 1.0 to 2.5% by mass with respect to the novolac type phenol resin. When the blending amount of hexamethylenetetramine is less than 0.5% by mass with respect to the novolak type phenol resin, not only is the early manifestation of the adhesive strength difficult, but also the residual carbon derived from the novolak type phenol resin after heating. Decreases, and the strength of the mud material after firing decreases. In particular, the strength after baking at 1500 ° C. indicates resistance to wear damage caused by hot metal during the brewing, and if the resistance to wear damage is too low, the durability of the mud material is lowered. Further, if the blending amount of hexamethylenetetramine exceeds 3.0% by mass with respect to the novolac type phenol resin, it is not preferable because the change in viscosity of the mud material with time increases.

Next, the refractory aggregate used for the mud material of the present invention comprises an oxide refractory raw material, a carbonaceous raw material, a silicon carbide raw material, a silicon nitride raw material, and the like.
Examples of the oxide refractory raw material include one or more selected from the group consisting of an alumina raw material, an alumina / silica raw material, a clay raw material, and a siliceous raw material, and more specifically, Examples thereof include sintered alumina, fused alumina, bangshale shale, bauxite, chamotte raw material, rholite, mullite, and andalusite.
The oxide refractory raw material constituting the refractory aggregate constitutes the main aggregate, and the blending amount of the oxide refractory raw material is in the range of 5 to 75 mass%, preferably 30 to 65 mass%. Here, when the blending amount of the oxide refractory raw material exceeds 75% by mass, the corrosion resistance decreases, which is not preferable, and when it is less than 5% by mass, the porosity tends to increase, which is not preferable.

  Further, the carbonaceous raw material constituting the refractory aggregate of the mud material is blended for the purpose of suppressing slag permeation and oversintering, and the blending amount of the carbonaceous raw material is 3 to 25% by mass, preferably Is in the range of 4-20% by weight. If the blending amount of the carbonaceous raw material is less than 3% by mass, it is not preferable because of excessive sintering. On the other hand, if it exceeds 25% by mass, the strength is remarkably lowered. Examples of the carbonaceous raw material include graphite, earth graphite, coal coke, petroleum coke, and powders of these cokes, graphite electrode scraps, carbon black, coal pitch, and petroleum pitch.

  Further, as the silicon carbide material constituting the refractory aggregate of the mud material, for example, a silicon carbide material produced by the Atchison method, a silicon carbide material obtained by reducing carbonization of silica, or the like can be used. The silicon carbide material is blended for the purpose of improving the corrosion resistance against slag, and the blend amount of the silicon carbide material is in the range of 5 to 50% by mass, preferably 10 to 30% by mass. If the amount of the silicon carbide raw material is less than 5% by mass, it is not preferable because the contribution of improving corrosion resistance is small. On the other hand, if it exceeds 50% by mass, the corrosion resistance to hot metal will be remarkably lowered.

  The silicon nitride material is also a material blended to improve the corrosion resistance like the silicon carbide material. For example, silicon nitride obtained by reducing and nitriding silica, silicon nitride obtained by directly nitriding metal silicon, For example, silicon iron nitride obtained by directly nitriding ferrosilicon can be used. The compounding amount of the silicon nitride material is 5 to 40% by mass, preferably 10 to 40% by mass. If the amount of the silicon nitride material is less than 5% by mass, it is not preferable because a sufficient effect for improving the corrosion resistance cannot be obtained. On the other hand, if it exceeds 40% by mass, the effect is saturated, and from an economical viewpoint. It is not preferable.

  In addition, 1 type, or 2 or more types of metal powder can also be mix | blended with the fireproof aggregate of the mud material of this invention. Examples of the metal powder include metal aluminum, metal silicon, and metal aluminum / silicon alloy. In addition, when mix | blending metal powder, the compounding quantity of metal powder is 0.5-8 mass%, Preferably it exists in the range of 1-6 mass%. When the blending amount of the metal powder is less than 0.5% by mass, the blending effect is not manifested, and when it exceeds 8% by mass, the blending effect is saturated, which is not preferable from an economical viewpoint.

  The particle size range of the refractory aggregate is 5 to 60% by mass of particles of 1.0 mm or more, preferably 10 to 50% by mass, and 5 to 45% by mass of particles less than 1.0 mm and more than 75 μm, preferably 10 to 10% by mass. Particles of 35% by mass and 75 μm or less are in the range of 20 to 70% by mass, preferably 30 to 60% by mass. In addition, the particle size of a refractory aggregate is measured using JIS Z8801-1; Screen for test-Part 1: Metal mesh screen.

  The mud material of the present invention is prepared by mixing refractory aggregates such as the above-mentioned oxide refractory raw materials, carbonaceous raw materials, silicon carbide raw materials, silicon nitride raw materials with a mixer, and then adding a predetermined amount of organic binder and curing agent. It can be manufactured by adding and kneading. The kneading time of the refractory aggregate and the organic binder is not particularly specified, but it is necessary that the refractory aggregate and the novolac type phenol resin are sufficiently mixed. The kneading time for that is, for example, 10 minutes to 120 minutes. It can be.

  In addition, examples of the mixer that can be used when producing the mud material of the present invention include, for example, an upper mixer, an Eirich mixer, a Fukai-type Coner mixer, and the like, but any mixer that has been conventionally used is particularly limited. It is not a thing.

Examples The present invention and comparative mud materials were prepared at the blending ratios shown in the following table. A kneading machine was used for kneading, and the kneading time was 20 minutes.

In the table,
The blending amount of the binder is adjusted so that the extrusion load of each mud material is about 4.2 kN. Here, the extrusion load is a load applied when a mud material is extruded at a constant speed from a capillary having a diameter of 20 mm and a length of 20 mm. If the mud is high, the viscosity is high and hardly deformed, and if low, the viscosity is low. It means a low-deformable mud material. The binder used was a novolak type phenolic resin having a different weight average molecular weight;
Method for measuring mud viscosity over time:
The extrusion load (A) immediately after preparation of the mud material and the extrusion load (B) after storage for 30 days in a 40 ° C. incubator were measured. It was evaluated as a change index.
Viscosity change index with time = (B) / (A) × 100
If the viscosity change index is less than 250, it can be satisfactorily filled in the actual machine for 3 months or more under the condition of being stored at room temperature, and more preferably less than 200. On the other hand, if the viscosity aging index exceeds 250, filling failure may occur. In the viscosity aging evaluation, the viscosity aging index is less than 200, ◎, 200-250 is ◯, and more than 250 is x;
Method for measuring mud curing time:
The prepared mud material was molded into φ56 mm × 13 mm and placed on a hot plate heated to 245 ° C., and the time until the plasticity of the upper surface of the sample was completely lost was measured. The presence or absence of plasticity was determined by whether or not deformation occurred when the upper surface of the sample was pressed with a metal spatula. If the curing time is 10 minutes or less, it can be determined that the adhesive strength has been developed at an early stage, and troubles such as natural brewing can be avoided even during continuous brewing operations where the crimping time is short. In the curing time evaluation, those having a curing time of 10 minutes or less were marked with ◯, and those with more than 10 minutes were marked with x;
Corrosion resistance against hot metal:
Corrosion resistance to hot metal was evaluated by a sample lining test using a high frequency induction furnace. A mud sample heated for 3 hours at 800 ° C. in a reducing atmosphere was combined in a crucible shape, 20 kg of pig iron was added as an erodant inside the crucible, and the mud sample was dissolved at 1550-1600 ° C. for 4 hours. Loss volume was measured. The erosion volume is indicated by an index with Comparative Product 1 being 100. The smaller the corrosion resistance index (vs. hot metal), the better the corrosion resistance.
Corrosion resistance to slag:
Corrosion resistance to slag was evaluated by a rotating drum erosion test method. A mud material sample heated at 800 ° C. for 3 hours in a reducing atmosphere was combined into a drum shape, and 1 kg of blast furnace slag was added as an erodant inside the drum and held at 1550 to 1600 ° C. for 4 hours. The erosion agent was replaced every hour, and the melting depth of the mud material sample after the test was measured. The erosion depth is indicated by an index with Comparative Product 1 as 100. Corrosion resistance index (The smaller the slag, the better the corrosion resistance.
In the evaluation of corrosion resistance, the index of corrosion resistance to hot metal and slag was less than 110, 、, 110 to less than 120 as ◯, and 120 or more as x.
Bending strength measurement method:
The prepared mud material was put into a 40 × 40 × 160 mm mold, molded at a pressure of 5.0 MPa, and dried at 300 ° C. for 12 hours in a dryer. After drying, the molded body was immersed in a coke breeze and heated at 1500 ° C. for 3 hours as a test piece, and the bending strength was measured. If the bending strength after heating is 5 MPa or more, it can be determined that there is good wear resistance, and it is more preferable if it exceeds 5.5 MPa. In addition, the bending strength of a test piece is measured according to JIS R2553. In the strength evaluation, a bending strength of 5.4 MPa or more was evaluated as ◎, 5.0 MPa or more and less than 5.4 MPa as ◯, and less than 5.0 MPa as x;
Kneading properties:
The kneading properties are evaluated by tactile feeling determination by human hands. In addition, kneaded mud material can be easily deformed and no cracks are generated at the time of deformation, 変 形 is slightly difficult to deform, or slightly cracks are generated at the time of deformation, difficult to deform, or many at the time of deformation The thing which a crack generate | occur | produced was set as x.

In the present invention products 1 to 5 and comparative products 1 to 3, the composition of the refractory aggregate and the type of the novolac type phenol resin are the same, and the blending amount of hexamethylenetetramine is changed. In Comparative products 1 and 2, the blending amount of hexamethylenetetramine was less than 0.5% by mass based on the blending amount of the novolac type phenol resin, and the curing time was long. In Comparative product 3, the blending amount of hexamethylenetetramine was over 3.0% by mass with respect to the blending amount of the novolac type phenol resin, and the change with time in viscosity was large. On the other hand, as for this invention products 1-5, the compounding quantity of hexamethylenetetramine exists in the range of 0.5-3.0 mass% on the outside with respect to the compounding quantity of a novolak-type phenol resin, and hardening time and Both the change in viscosity with time showed good characteristics, and there were no problems with the characteristics such as corrosion resistance and strength characteristics.
In the present inventions 6 to 9 and the comparative products 4 and 5, the blending of the refractory aggregate and the blending amount of hexamethylenetetramine with respect to the novolak type phenol resin are the same, and the weight average molecular weight of the blended novolak type phenol resin is changed. Is. Comparative product 4 was a blend of a novolac type phenol resin having a weight average molecular weight of 1300, and the curing time was long. Comparative product 5 is a blend of a novolak type phenolic resin having a weight average molecular weight of 12,000, and the novolac type phenolic resin itself has a very high viscosity, and the mud material after kneading can be adjusted to an appropriate viscosity. It was difficult and could not be put to practical use as a mud material. Invention products 6 to 9 are blended with a novolak type phenolic resin having a weight average molecular weight within the range of the present invention, and there is no problem in curing time and viscosity adjustment, and the viscosity change with time, corrosion resistance, etc. There was no problem with the characteristics.
Invention products 10 to 13 were obtained by variously changing the blending amount of the same novolak type phenol resin as that of the present invention product 3, but there were no problems in the curing time and the change in viscosity over time.
Invention products 14 to 16 were prepared by variously changing the composition of the refractory aggregate, but there was no problem in the curing time and the change in viscosity over time.
The comparative product 6 is a mud material in which the polyester acid amide amine salt disclosed in Patent Document 1 is blended with the comparative product 1 in an amount of 3% by mass. Compared with Comparative Product 1, the effect of reducing the amount of binder is seen, and the curing time is shortened, but the degree is low, and the actual machine does not develop strength at an early stage, completely preventing problems such as natural sag. It cannot be lost.

Claims (3)

  In a blast furnace outlet hole closing mud material containing a refractory aggregate, an organic binder and a curing agent, the organic binder is a novolac resin having a weight average molecular weight of 3000 to 10,000, and the curing agent is hexamethylene. A mud material for closing a blast furnace outlet hole, characterized in that it is tetramine and the blending amount of hexamethylenetetramine is in the range of 0.5 to 3.0% by mass with respect to the novolac resin.   The mud material for blockage | closure of a blast furnace outlet hole of Claim 1 whose compounding quantity of a novolak-type resin is in the range of 10-30 mass% by an outer shell with respect to 100 mass% of refractory aggregates.   The refractory aggregate has a blending ratio of 5 to 75% by mass of oxide refractory material, 3 to 25% by mass of carbonaceous material, 5 to 50% by mass of silicon carbide material, and 5 to 40% by mass of silicon nitride material. Item 3. A mud material for closing a blast furnace outlet hole according to item 1 or 2.