JPS609984B2 - Blast furnace taphole mud material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mud material for a blast furnace gun port, and more specifically, the present invention relates to a mud material for a blast furnace gun port, and more specifically, to the bone material of the mud material, alumina of 1 micron or less, at least one superconductor selected from silicic acid and silicon carbide is used. By using fine powder in place of viscosity, or in combination with viscosity, it is possible to obtain the appropriate plasticity necessary for filling the iron outlet with a significantly smaller amount of binder (tar-based or resin-based), and to reduce the volatile content in mud. By significantly reducing
This invention relates to a mud material for tapholes that makes it possible to shorten firing time and improve the structural strength of the mud material.

The recent increase in the amount of tapped iron due to larger blast furnaces and higher pressure operation has led to an increase in the number of times of tapping per day due to the use of lap tapping guns, etc.

As a result, the likelihood of opening or blocking the tap hole has increased, and the damage to the tap hole has increased dramatically, making stable operation of the blast furnace and work stability an important issue. Each type of blast furnace has 1 to 4 tapholes in one furnace, and these tapholes are used alternately during the tapping operation, so the intervals between opening and closing of the tapholes are the same as the normal number of tapholes for the same taphole. Depending on the condition of the tap duct, it may take several days, or it may take around an hour in cases of continuous tapping.

From these operational points of view, the following characteristics are required of mud materials. [1' Must have optimal stickiness and plasticity to facilitate taphole filling work with a mud gun.

■ The mud material after filling the tap hole requires a short firing time and should be sintered early. (3) The strength of the dawn stripe after firing has little variation depending on the length of firing time, making it easy to perform checkout work.

[4] Hot metal: It must be corrosion resistant against melting, minimize expansion of the taphole diameter, and maintain an appropriate taphole depth. By using hot metal that satisfies the above conditions, the inside of the furnace The molten iron is always controlled at a low level, the erosion of the blades is reduced, and secondary damage caused by sudden wind breaks due to mechanical failure can be prevented, which plays a major role in productivity and safety. can be accomplished.

Various refractory materials have been used in the past in order to provide properties as a mud material for the blast furnace taphole.

For example, materials commonly used are those made by adding and kneading tar, etc. as a binder to lowite, coke, and refractory clay, or by adding and mixing binders such as tar and pitch to alumina, coke, coke, silicon carbide, and fireclay. However, the following points have not yet been fully resolved. 1 Fireclay and tar are generally used to obtain the plasticity described in the above characteristics (item 1), but fireclay has adhering water and crystallization water as raw materials, so it is necessary to add tar to obtain the appropriate plasticity. Therefore, the amount of gas generated in the mud material increases, the firing time required for special selection 2-2 becomes longer, and rapid leech formation is inhibited, and gas dissipation to the outside world is insufficient. This is undesirable because there is a danger that the accumulated gas will blow out at the time of the checkpoint.2 Regarding the above-mentioned clause 4-, under usage conditions where the mud material is forced to be rapidly heated, a large amount of volatile matter in the tar and fire-resistant As the amount of gas generated due to the moisture in the clay increases and the fireclay shrinks, the structure of the wood becomes coarser and defects such as more cracks occur inside the taphole.

The present invention was developed as a result of various researches aimed at solving the above-mentioned defects.
This was achieved by reducing the raw material particle size in the mud material raw material mixture to ultra-fine particles of 1 micron or less, and the present invention makes it possible to improve the structural strength of the mud material and significantly shorten the firing time, making it an advantageous mud material for stable operation. were able to provide.

The present invention will be explained in detail below.

The binder (tar-based or resin-based) used as a binder for mud materials is quite viscous (200-35 ratio p/6).
030) is high, and it was found that the amount of binder required to obtain the same plasticity is particularly controlled by the blending ratio of ultrafine castle particles of 1 micron or less in the mud material compounding raw materials.

In other words, the minimum particle size in the blended raw materials is 5 to 15 grains for each raw material.
In the micron range, the amount of binder consumed is high, the stickiness and plasticity are insufficient, and the rapid heat exposure after filling results in a large amount of gas generation.
This impairs the stability of the structure and reduces corrosion resistance and the risk of ejection of retained gas when opening the iron outlet. If the particle size is 15 microns or more, stickiness and plasticity cannot be obtained and filling operations are impossible. When the particle size is 5 to 1 micron, there is no difference in binder consumption compared to when a secondary fireclay is used, and the effect is small. The use of particle sizes below 1 micron significantly reduces binder consumption and provides optimum toughness and plasticity. When the particle size is 1 micron or less, if the mixing ratio of various raw materials is 4% by weight or less, the stickiness and plasticity will be insufficient and the filling operation will be impossible.

If it exceeds 30% by weight, the stickiness becomes too strong, making the filling operation difficult, or conversely, a large amount of binder is required to enable the filling operation, causing the above-mentioned disadvantages.

In the case of silicic acid and silicon carbide, if less than 2% by weight is used, both stickiness and plasticity will be insufficient, and if 2% by weight or less is used,
In the above case, the stickiness becomes too strong and problems arise as in the case of alumina. The alumina used in the present invention is sintered or dragon fused alumina (commercially available, hereinafter the same) as Yama 20395.
~99%, Si02 and other 1~5% chemical components, moisture content is 0.1% or less, and particle size is adjusted to 1 micron or less (average particle size 0.4 French). For the above reasons, the amount is 4 to 3% by weight.

Silicic acid (commercially available, the same applies hereinafter) has a chemical composition of 95 to 98% Si, 2 to 5% of other components, 0.3% or less of moisture,
The particle size is adjusted to 1 micron or less (average particle size 0.5 French), for example, Silica Flower (trade name) is used, and the blending ratio is preferably 2 to 15% by weight for the above reasons.

Silicon carbide (commercial product "the same applies hereinafter") has an SIC of 85 to 98%,
Has a chemical composition of fixed carbon 0.3-4%, moisture 0.1%
Below, the particle size is adjusted to 1 micron or less (average particle size 0.7 French), and the blending ratio is 2 to 2 for the above reasons.
% by weight is preferred.

By using various raw materials with a diameter of 1 micron or less in an optimal blending range of 2 to 3% by weight, the amount of tar added can be reduced by approximately 38% compared to mud materials using conventional fireclay, and the volatile content is reduced by 42%. It became possible to reduce it.

As mentioned above, by adjusting the optimal blending ratio of various raw materials, it is possible to significantly reduce the volatile content compared to conventional mud materials, shorten the firing time, improve structural strength and corrosion resistance, and improve workability. Good results were obtained in these respects.

Next, the present invention will be specifically explained with reference to Examples.

Example The raw materials used in this example are as follows.

Raw stone (produced in Korea) Chemical composition: Burning loss 3.4%, Si
0275.7%, AI2031947%, others 1.2%,
Water 0.4%, particle size below 1.0 (weight) Coke (for domestic castings) Volatile content 2.0%, ash content 8.1%, fixed carbon 89.2%, attached moisture 0.5%, particle size 4-1 side 57.0
%, 1 leg or less 43.0% (weight) Silicon carbide (commercial product)
Chemical composition: SIC 87.4%, fixed carbon 3.7%, particle size 3-1 95.4%, below 1st side 4.6%, particle size 0.1
Below 100% (weight) silicon carbide super fine powder (commercial product) Chemical composition SIC 96.3%, fixed carbon 0.3%, particle size 1 micron or less (average particle size 0.6 French) 100% (weight) super alumina Fine powder (commercially available) Chemical composition: 20398.5%, particle size: 1 micron or less (average particle size: 0)
．． 4) 100% (weight) Silicic acid super powder (commercial product, e.g. silica flour) Chemical composition Si0297.1%, particle size 1
Micron or less (average particle size 0.5 French) 100% (weight) Fireclay (Osuji clay; domestically produced) Chemical composition Loss on burning 10.
8%, AI20333.4%, Si0254.8%, attached moisture 4.2%, particle size 0.3 skin or less 98% (weight) Fire resistance SK33 tar (commercial product, refined tar No. 2) Specific gravity 1.198/6000 , viscosity 34 ratio p/60oo, moisture 0.05%, distillate fraction up to 250 qo, distillation analysis value 12.
2%, distillate between 250 and 300°C 11.0%, 300
Distillate between ~350q○ 16.2%, fixed carbon 29.1
% (weight) Pitch (commercial product) Softening point (BR method) 130
00, volatile content 36.7%, fixed carbon 63.0%, ash content 0
．． 3% (by weight) of the above raw material was added to Example No. 1 in Table 1. 1~N
o. Samples were prepared using a commercially available lower mixer at the blending ratio shown in No. 7 and the blending ratio of Comparative Example to a total weight of 250k9, and mixed for 2 minutes.

The line temperature during kneading was maintained at 46°C. The quality characteristics of various formulations obtained by the above method are also shown in Table 1.

Table 1 Note 1) Murashiki degree is measured by asphalt penetration tester (JIS method)
Measurement results at a sample temperature of 45°C 2) As a way to check the filling workability, the extruder was made using a 50mm metal frame x 200L cylinder with a nozzle with a slope of 300mm at the end. Tip nozzle diameter 1
Fill the cylinder in Example 5 with mud material and set the sample temperature to 4.
After holding at 5℃ for 30 minutes. Measure the amount of mand material extruded from the nozzle tip using hydraulic pressure of 25mm.

3) The slag erosion resistance test was carried out using a rotary arc furnace erosion tester (a rotating model of a 500L metal frame x 500L cylinder with both ends sealed with iron lids). The sample has a shape of 60 x 65 x
Molded into 200 pieces at a molding pressure of 100mm. Reduction 800
The specimen was treated at ℃/5 days. Samples 1 to 7 and the comparative example were placed inside the rotary arc furnace erosion tester described above at the same time. The test was carried out under the following conditions (temperature: 1550°C/2 days, rotation speed: 8 times/min, blast furnace slag replaced twice at 1-/time). Comparison was made based on the maximum erosion depth (example) of the samples.

4) The specimens used to measure various physical properties after reduction firing at 1350°C/2 days were those with a shape of 50 x 50 days, and a molding pressure of 100/2 days.
The one made by a female was used.

From the above experimental results, the amount of tar added can be changed from 17% in the comparative example to Example No. of the present invention without impairing workability. 1~No.
The volatile content was reduced by about 40% from 15.4% to 8.7% (weight), and the structural strength was also improved by about 30% and corrosion resistance by about 40%. From the above results, we were able to significantly improve the mud material requirements for the taphole.

When the mud material of the present invention was put to practical use in a large high-pressure blast furnace of 4,500 liters, the tapping time per tap was 110 to 130.
The time required for firing was reduced to 140 to 160 minutes, and the required firing time was reduced to two-thirds of the conventional time, resulting in significant improvements in terms of stability of blast furnace operation, safety of furnace front work, etc.

Claims (1)

[Claims] 1 At least one particle selected from alumina, silicic acid, and silicon carbide of 1 micron or less for the refractory aggregate whose particle size has been adjusted
A matwood material for a blast furnace taphole, which contains 2 to 30% by weight of ultrafine seed powder and is kneaded with the addition of an organic binder.