JPS6113559B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for constructing monolithic refractories for lining molten metal containers such as ladles, tundishes, and gutters used in the steel industry. The conventional method of lining molten metal containers with pouring material involves adding refractory powder to a mixer at a predetermined ratio, adding moisture in the area required for pouring, and mixing to give fluidity. A construction method has been used in which the monolithic refractories obtained are transported to a construction site, and placed in that state between the core and outer shell of the container to line the container. In the construction method described above, a phenomenon in which coarse particles and fine particles are separated occurs to some extent during the transport of the pouring material. When such refractories are applied to the container, the particles of the lined construction material become uneven, which accelerates the melting loss of the constructed material during operation or causes abnormal partial melting loss, resulting in a decrease in durability. I was forced to. Furthermore, since these monolithic refractories contain a large amount of water, they do not retain their shape, and it takes a long time to remove the core from the mold after construction. Therefore, a method of transporting the powder as a powder to the construction site, adding a hardening agent and kneading it on the spot has been adopted, but this method generates a lot of dust when it is put into the mixer, and fixed equipment such as dust collection equipment is required. This will worsen the working environment at the construction site. If mixing takes too long, the previously applied construction material will begin to harden, so mixing can only be carried out for a short period of time. Further, as long as such a construction method is used, the amount of moisture, binder, etc. in the monolithic refractory increases compared to other refractories, and such kneading makes it difficult for fine powder to adhere around coarse particles. Since monolithic refractories contain relatively large amounts of additives, they have disadvantages such as low filling properties of the constructed body, low porosity, and inability to obtain after-strength. The method of the present invention is a method obtained through various studies to eliminate defects in the work and construction body when lining monolithic refractories by pouring or vibration forming, and the gist thereof is as follows. However, in the method of pouring or vibration forming the lining of a molten metal container with a monolithic refractory, the monolithic refractory is pre-pressurized and kneaded with less moisture than the total moisture content required for construction. This method of constructing a monolithic refractory is characterized in that the remaining moisture or this and an additive are added during construction, and the mixture is mixed and then constructed. In the method of the present invention, it is important to add water in advance that is less than the total amount of water required for construction and then pressurize and knead it, although this is partly to avoid complicated work and dust generation at the construction site. The purpose is to make the moisture coating on the surface of the refractory particles thin and uniform, thereby reducing the distance between the refractory particles and improving the filling properties and strength of the construction body. That is, in the present invention, the coarse particles and the characteristic particles are brought close to each other due to the effect of kneading the monolithic refractory with a small amount of water sufficient to thinly coat the particles by pressurized kneading. Since the particles tend to come closer to each other due to the surface tension of the uniformly thin adhering water, no particle size separation phenomenon occurs during the transportation process of such refractories. In this way, since it is a monolithic refractory that has been pressurized and kneaded in advance with the addition of less moisture than the total moisture content required for construction, additional moisture that reaches the predetermined amount at the construction site or this It can be easily kneaded in a short time by adding additives such as a curing agent and a curing agent. Therefore, by lining with the above-described refractory material, a constructed body with a uniform structure and high strength can be obtained. The construction itself is easy for monolithic refractories because of its high fluidity even when the moisture content is low. Since the moisture content is low, demolding can be done quickly, and when a hardening agent is added, the time can be further shortened. It not only saves labor and improves the environment during construction work, but also increases the durability of the constructed structure. Examples will be described below.

【table】

[Table] 5% water was added to the mixture A in the proportions shown in Table 1, the mixture was kneaded under pressure in a wet kneader for 20 minutes, the mixture was stored in vinyl for 48 hours, and the mixture Add 1.5% moisture again and add 2
Mixed for a minute. The kneaded material obtained in this way was placed on a workbench.
Specimen No. 1 was manufactured by placing it in a 40 x 40 x 40 mm mold and applying vibrations of 3.600 VPM. At the same time, 8% water was added to the same formulation A and mixed for 20 minutes in a mixer, and the same vibration cycle as above was applied to obtain specimen No. 4. Furthermore, 5% water was added to the same formulation and mixed in a mixer for 20 minutes, and after storage for 48 hours, 1.5% water was added and mixed again in the mixer to prepare specimen No. 5 of the same size. Additionally, 5% of the formulations in Table 1 B and C
% of water was added to each mixture, kneaded under pressure for 15 minutes, and the kneaded product was placed in a bag and stored tightly. After 48 hours, the mixture was taken out, an additional 1.6% moisture was added, and the mixture was mixed for 2 minutes with a mixer. The mixture thus obtained was placed in a mold of 40 x 40 x 40 mm and specimens No. 2 and No. 3 were prepared under the same conditions.
8.5 for formulations B and C for comparison.
Add % moisture and mix for 15 minutes with a mixer 40 x 40
Specimen No. 6 was placed in a ×40mm formwork under the same conditions as above.
and No. 7 was created. The compressive strength and fluidity (fluidity index) of the above seven types of specimens were measured after drying at 110°C for 24 hours. As shown in Table 2, specimen No. 1 according to the embodiment of the present invention.
The compressive strength was 2 to 4 times higher than that of Comparative Examples of the same formulation No. 4 and No. 5, and the fluidity was more than 3 times higher. Example No. 2 of the present invention has four times the compressive strength and twice the fluidity compared to No. 6 with the same blend, and Example No. 3 of the present invention also has a compressive strength twice as high as No. 7 with the same blend. The compressive strength was 3 times higher and the fluidity was 2 times higher. Furthermore, each monolithic refractory prepared under the same conditions as specimens No. 1 and No. 4 was placed between the core and outer shell of the tap trough of a blast furnace and installed using a rod-shaped vibrator. The construction condition was adjusted in the same way as Specimen No. 1, and although the water content was low, it had high fluidity and a dense construction body. In contrast, specimen No. 4
A product prepared in the same manner as above had a high moisture content but low fluidity, and coarse particles and fine particles showed an extreme tendency to separate, making it impossible to obtain a satisfactory construction body. After construction, cores similar to No. 1 could be demolded after 3 hours, but cores similar to No. 4 could not be demolded until 20 hours had passed. In addition, when we measured the erosion rate using the same part, we found that the same one as No. 1 was 6.1 mm/1000t, which was a 20% improvement compared to the one similar to No. 4. As described above, according to the present invention, in the construction of monolithic refractories by pouring or vibration molding, the monolithic refractories are kneaded under pressure in advance with less moisture than the total moisture content required for construction. Effects such as labor saving, environmental improvement, and increased durability of the construction body can be obtained.

Claims (1)

[Claims] 1. In a method of pouring or vibration forming the lining of a molten metal container with a monolithic refractory, the monolithic refractory is kneaded under pressure in advance with less moisture than the total moisture content required for construction, A method for constructing a monolithic refractory, which comprises adding the remaining water or an additive thereto during construction, mixing the mixture, and then constructing the monolithic refractory.