JP6384511B2 - Castable refractories - Google Patents

Description

  The present invention relates to a castable refractory using a blast furnace slag line material after use.

  Various refractories used in steelworks are dismantled after use and reused or discarded. In recent years, there is a problem such as a decrease in landfill, and the demand for reusing refractories after use is increasing. If the refractory after use can be sorted by equipment or part where the refractory is installed or by the material of the refractory, there is a possibility that it can be reused as a refractory raw material again. Patent Document 1 discloses a technique in which used alumina, rholite, silicon carbide, and carbonaceous refractory are pulverized and used as a raw material for unfired brick.

Japanese Patent No. 5366560 Japanese Patent No. 4856772

  However, most of the blast furnace refractories containing silicon carbide-carbon are disposed of in spite of the large amount of refractory used. One reason for this is considered to be that blast furnace refractories need to be constructed on site in a short time, and castable refractories are poured into the construction. Spent blast furnace refractories contain a mixture of alumina, silicon carbide, carbon, and other compositions, but when pulverized and reused, the amount of water mixed is less than when virgin raw materials are used. There is a tendency to increase. When the amount of mixed water in the castable refractory increases, the porosity of the refractory after construction increases and the problem arises that the corrosion resistance deteriorates.

  For this reason, the slag line material used for a slag line part among blast furnace refractories contains 50 mass% or more of expensive silicon carbide as a refractory raw material, but is hardly reused. Compared to slag line material, the metal line material in the blast furnace refractory has a low silicon carbide content. Therefore, if the used slag line material can be reused for the metal line material, it becomes a very useful technique.

  Blast furnace refractories are composed of oxides such as alumina and spinel, carbides, pitch, carbon black, metal, alumina cement, dispersant and the like. Among these, according to Patent Document 2, sodium hexametaphosphate and β naphthalene sulfonate formalin condensate are used as the dispersant. Recently, carboxyl group-containing polyether dispersants have also been used for blast furnace refractory metal line materials.

  When these conventionally used dispersants are used, the virgin raw material is used when pulverized so that the grain size of the blast furnace slag line material is 1 mm or less after use and used as a part of the castable refractory raw material. If the amount of the dispersant used is not increased, the fluidity is deteriorated and the kneading failure occurs. This is because O and H contained in hydrophobic materials such as pitch and carbon black in blast furnace refractories are separated and disappeared by heating with high temperature blast furnace slag, and the hydrophobicity of these materials is further enhanced. It is thought that.

  Further, when the amount of the dispersant is increased in order to avoid kneading failure, there is a problem that the curing time after the construction becomes long and the time until it can be used as a blast furnace iron becomes long. Furthermore, when the amount of mixed water is increased for the purpose of improving fluidity, there is a problem that the porosity of the metal line material after construction increases and the corrosion resistance decreases. The present invention has been made in view of the above problems, and is a castable refractory containing a blast furnace slag line material after use, which can be constructed without increasing the amount of mixed water compared to the case of using a virgin raw material. The purpose is to provide refractories.

The features of the present invention for solving such problems are as follows.
(1) A blast furnace slag line material after use having a particle size of 1 mm or less is contained in an amount of 10% by mass to 50% by mass, and a carboxyl group-containing polyether dispersant as an outer coating is 0.1% by mass to 0%. A castable refractory containing 3% by mass or less and containing 0.01% by mass to 0.5% by mass or less of polyoxyethylene oleyl cetyl ether as an outer shell.

  The castable refractory containing the blast furnace slag line material after use of the present invention as a raw material can be constructed as a metal line material of the blast furnace refractory without increasing the amount of mixed water. Thereby, it can suppress that the porosity of the metal line material after construction becomes high, and can suppress the fall of corrosion resistance.

A sectional view of the blast furnace refractory is shown. The perspective view of a blast furnace refractory is shown.

  When using the blast furnace slag line material after use as a castable refractory for the blast furnace metal line material, the present inventors set the particle size of the blast furnace slag line material after use to 1 mm or less and 10 masses. % Or more and 50% by mass or less, a carboxyl group-containing polyether dispersant as a dispersant is added by 0.1% to 0.3% by mass, and polyoxyethylene oleyl cetyl ether is externally applied. 0.01 mass% or more and 0.5 mass% or less are contained. Thereby, it discovered that it could construct as a metal line material of a blast furnace refractory, without increasing the amount of mixed water, and completed this invention. Hereinafter, the present invention will be described through embodiments of the present invention.

  FIG. 1 shows a cross-sectional view of a blast furnace refractory 10. FIG. 2 is a perspective view of the blast furnace refractory 10. The blast furnace refractory 10 is composed of a metal line material 12 and a slag line material 14. The hot metal 16 and the blast furnace slag 18 discharged from the blast furnace are transferred to the hot metal transfer container (not shown) through the blast furnace refractory 10.

  In the blast furnace refractory 10, the metal line material 12 is provided on the lower side of the blast furnace refractory 10 so that the interface between the hot metal 16 and the blast furnace slag 18 is in contact, as shown in FIGS. 1 and 2. The slag line material 14 is provided on the upper side of the blast furnace refractory 10 so that the interface between the blast furnace slag 18 and air is in contact therewith. The metal line material 12 and the slag line material 14 are formed by pouring and casting castable refractories.

  The blast furnace refractory 10 is disassembled after being used a predetermined number of times. The dismantled blast furnace refractory 10 after use is recovered and then crushed. The crushed blast furnace refractory 10 after use is separated into a metal line material and a slag line material using the specific gravity difference. Separation of the metal line material and the slag line material is performed using, for example, sand having a specific gravity intermediate between the specific gravity of the metal line material and the specific gravity of the slag line material.

  The castable refractory according to this embodiment is crushed so that the particle size is 1 mm or less, and uses a slag line material after use containing 50% by mass or more of silicon carbide as a raw material. The particle size of 1 mm or less is a particle size that is sieved with a sieve having an opening of 1 mm and sieved under the sieve. Further, if the particle size of the slag line material for use is larger than 1 mm, the particle size of silicon carbide increases, and the performance of silicon carbide as an antioxidant is unfavorable.

  Moreover, the castable refractory according to the present embodiment contains the slag line material after use having a particle size of 1 mm or less in an amount of 10% by mass to 50% by mass. When the content of the slag line material after use is less than 10% by mass, the amount of silicon carbide added is reduced, and the antioxidant effect is lowered, which is not preferable. Further, if the content of the slag line material after use is more than 50% by mass, the amount of silicon carbide added is excessively increased, and the corrosion resistance against hot metal is lowered, which is not preferable.

  The pitch and carbon black contained in the slag line material 14 in the blast furnace refractory 10 are heated by the blast furnace slag 18 to become highly hydrophobic carbon. When the slag line material after use is pulverized, the slag line material is crushed from the portion containing carbon having low strength, so that the surface of silicon carbide is covered with carbon. For this reason, the slag line material after use has low wettability with water, fluidity is deteriorated, and kneading failure tends to occur. If the amount of the dispersant is increased in order to avoid kneading failure, the curing time after construction becomes long and the workability deteriorates. Moreover, when the amount of mixed water is increased for the purpose of improving fluidity, the porosity of the metal line material after construction increases and the corrosion resistance decreases. The mixed water amount is the amount of water added when kneading the refractory material.

  For this reason, the castable refractory in this embodiment contains 0.01% by mass or more and 0.5% by mass or less of polyoxyethylene oleyl cetyl ether as a dispersant. Thereby, the problem of kneading | mixing failure, deterioration of workability, and the fall of corrosion resistance can be solved. In addition, when content of polyoxyethylene oleyl cetyl ether is less than 0.01 mass%, since sufficient fluidity | liquidity is not obtained, it is unpreferable. Moreover, if the content of polyoxyethylene oleyl cetyl ether is more than 0.5% by mass, the porosity of the metal line material after construction increases due to the foaming property of polyoxyethylene oleyl cetyl ether, and the corrosion resistance decreases. It is not preferable. As polyoxyethylene oleyl cetyl ether, for example, Neugen (registered trademark) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. can be used.

  In the castable refractory according to the present embodiment, a carboxyl group-containing polyether dispersant is further added as a dispersant in an amount of 0.1% by mass to 0.3% by mass. If the content of the carboxyl group-containing polyether dispersant is less than 0.1% by mass, improvement of the wettability of the alumina fine powder and the alumina cement becomes insufficient, which is not preferable. Moreover, since the hardening time after construction will become long when content of a carboxyl group-containing polyether type dispersing agent exceeds 0.3 mass%, it is unpreferable. As the carboxyl group-containing polyether dispersant, for example, Tight Rock (registered trademark) manufactured by Kao Corporation or Mighty (registered trademark) manufactured by Kao Corporation can be used. In the present embodiment, the outer jacket is a content ratio in which the total mass of other raw materials excluding polyoxyethylene oleyl cetyl ether and carboxyl group-containing polyether dispersant is 100.

  Thus, the castable refractory according to the present embodiment contains a used blast furnace slag line material having a particle size of 1 mm or less in an amount of 10% by mass to 50% by mass, and a carboxyl group-containing polyether dispersant as a dispersant. Is 0.1 mass% or more and 0.3 mass% or less by outer coating, and polyoxyethylene oleyl cetyl ether is 0.01 mass% or more and 0.5 mass% or less by outer coating. The castable refractory thus configured can be constructed as a metal line material for a blast furnace refractory without increasing the amount of mixed water as compared with the case where a virgin raw material is used. Thereby, it can suppress that the porosity of the metal line material after construction becomes high, and can suppress the fall of corrosion resistance.

Next, examples of the present invention will be described. Table 1 shows the components of the castable refractories of Invention Examples 1 to 5, the amount of mixed water, the apparent porosity, and the erosion index. Table 2 shows the components of the castable refractories of Reference Example 1 and Comparative Examples 1 to 4, the water mixing ratio, the apparent porosity, and the erosion index. In addition, the post-use slag line material used in the present Example is 32.0% by mass of Al ₂ O ₃ , 52.0% by mass of SiC, 2.7% by mass of C, and 7.0% by mass of SiO ₂ , MgO is contained at 1.0 mass%.

  Invention Examples 1 to 5 shown in Table 1 are castable refractories containing 10 to 50% by mass of the slag line material after use. The dispersant contains Neugen (registered trademark) which is polyoxyethylene oleyl cetyl ether in addition to Tightlock (registered trademark) which is a commonly used carboxyl group-containing polyether dispersant.

  Invention Example 1 contains 20.0% by mass of the slag line material after use, as a dispersant, 0.1% by mass of Neugen (registered trademark) as an outer covering, and 0.05% of tight rock (registered trademark) as an outer covering. It is a castable refractory containing 20% by mass.

  Invention Example 2 contains 20.0% by mass of the slag line material after use, Neugen (registered trademark) as a dispersant is 0.20% by mass, and Tightlock (registered trademark) is 0.00. It is a castable refractory containing 20% by mass.

  Invention Example 3 contains 20.0% by mass of the slag line material after use, and 0.50% by mass of Neugen (registered trademark) as a dispersing agent and 0.5% by weight of Tightlock (registered trademark) as the dispersing agent. It is a castable refractory containing 20% by mass.

  Invention Example 4 contains 10.0% by mass of the slag line material after use, 0.20% by mass of Neugen (registered trademark) as a dispersing agent and 0.2% by mass of Tightlock (registered trademark) as an outer coating. It is a castable refractory containing 20% by mass.

  Invention Example 5 contains 50.0% by mass of the slag line material after use, 0.20% by mass of Neugen (registered trademark) as a dispersing agent and 0.2% by weight of Tightlock (registered trademark) as an outer coating. It is a castable refractory containing 20% by mass.

  Invention Example 6 contains 20.0% by mass of the used slag line material, 0.20% by mass of Neugen (registered trademark) as a dispersing agent, and 0.2% by weight of Tightlock (registered trademark) as an outer covering. It is a castable refractory containing 10% by mass.

  Invention Example 7 contains 40.0% by mass of the slag line material after use, Neugen (registered trademark) is 0.20% by mass as a dispersant, and Tightlock (registered trademark) is 0.00. It is a castable refractory containing 30% by mass.

  Reference Example 1 does not contain a slag line material after use, contains silicon carbide having a particle size of 0.075 mm or less at 10.0% by mass, and tight lock (registered trademark) as a dispersing agent has a thickness of 0.0. It is a castable refractory containing 20% by mass.

  Comparative Example 1 contains 20.0% by mass of slag line material after use, Neugen (registered trademark) as a dispersing agent with an outer coating of 0.004% by mass, and Tightlock (registered trademark) with an outer coating of 0.20. It is a castable refractory containing mass%.

  Comparative Example 2 contains 20.0% by mass of the slag line material after use, 0.60% by mass of Neugen (registered trademark) as a dispersant, and 0.20 of Tightlock (registered trademark) as an outer shell. It is a castable refractory containing mass%.

  Comparative Example 3 contains 20.0% by mass of slag line material after use, only 0.50% by mass of Tightlock (registered trademark) as a dispersant, and no castable Neugen (registered trademark). Refractory.

  Comparative Example 4 is a castable refractory containing 20.0% by mass of slag line material after use and containing sodium polyacrylate and sodium naphthalene sulfonate formalin condensate as a dispersant.

  Comparative Example 5 contains 20.0% by mass of slag line material after use, only 0.20% by mass of Neugen (registered trademark) as a dispersant, and castable that does not contain tight rock (registered trademark) Refractory.

  In any of Invention Examples 1 to 7, Reference Example 1, and Comparative Examples 1 to 5, the raw materials were weighed to 2.5 kg, water was added, and the mixture was kneaded with a universal mixer for 3 minutes. Then, it was cast into a (53/78) × 35 × 160 mm trapezoidal column and a 40 × 40 × 160 mm rectangular parallelepiped mold, and was shaken with a desktop vibrator for 20 seconds. Then, after leaving for one day, the frame was removed and dried at 110 ° C. for 24 hours.

  The apparent porosity of a 40 × 40 × 160 mm sample was measured using the Archimedes method using water. Samples of (53/78) × 35 × 160 mm were subjected to reduction firing at 1400 ° C. × 3 hours in a coke breeze for evaluation of corrosion resistance, and then installed in a high-frequency induction furnace as a set of eight. In that, 6.8 kg of pig iron was dissolved and held at 1600 ° C. for 3 hours. When the temperature reached 1600 ° C., 200 g of blast furnace slag was added, and the slag was replaced every hour. Then, the site where the dimensional change before and after the test was the largest was measured, the dimensional change before and after the test of Reference Example 1 using the virgin raw material was taken as 100, and the erosion index was normalized with the dimensional change of the inventive example and the comparative example. Corrosion resistance was evaluated.

  In Examples 1 to 7 of the present invention, the material could be poured in with a mixed water amount similar to that in Reference Example 1 using virgin raw materials. Further, the apparent porosity and the melt index of the castable refractory after construction were both as small as or better than those of Reference Example 1.

  On the other hand, in Comparative Example 1, although the amount of mixed water was 8.0% by mass, a kneading failure occurred, and the material could not be poured and applied. Moreover, the comparative example 2 was able to pour and construct the material with the same amount of mixed water as the reference example 1. However, there was much foaming of the dispersant, the apparent porosity of the castable refractory after construction increased, and the melting index increased.

  Moreover, although the comparative example 3 was able to pour material with the same amount of mixed water as the reference example 1, it took a long time to construct and harden, and the workability of the castable refractory was worse than that of the reference example 1. . Further, in both Comparative Example 4 and Comparative Example 5, the amount of mixed water was set to 8.0% by mass as in Comparative Example 1, but kneading failure occurred, and the material could not be poured into the construction.

  As described above, the blast furnace slag line material after use having a particle size of 1 mm or less is contained in an amount of 10% by mass to 50% by mass, and a carboxyl group-containing polyether dispersant as an outer coating is 0.1% by mass or more. A castable refractory containing 0.3% by mass or less and containing 0.01% by mass to 0.5% by mass or less of polyoxyethylene oleyl cetyl ether is a metal of a blast furnace refractory without increasing the amount of mixed water. Can be cast as line material. And while being able to suppress that the hardening time of the metal line material constructed by pouring is prolonged, it can be suppressed that the porosity of the castable refractory after construction can be suppressed, and thereby the corrosion resistance can be prevented from lowering. It was.

10 Blast furnace refractories 12 Metal line material 14 Slag line material 16 Hot metal 18 Blast furnace slag

Claims (1)

  Blast furnace slag line material after use with a particle size of 1 mm or less is contained in an amount of 10% by mass to 50% by mass, and a carboxyl group-containing polyether dispersant as an outer coating is 0.1% by mass to 0.3% by mass. % Castable refractory material containing 0.01% by mass or more and 0.5% by mass or less of polyoxyethylene oleyl cetyl ether as an outer shell.