KR19980046769A - Basic Refractories for Timing Ladles - Google Patents

Abstract

The present invention relates to a basic refractory used in the slack-line of the Timing ladle, and its object is to provide a basic refractory excellent in corrosion resistance and spalling resistance.

The present invention for achieving the above object is a magnesia-zirconia clinker containing 15-25% by weight of a zirconia component: 60-70% by weight, alumina-magnesia-based spinel: particle size of 10㎛ or less: 10-20% by weight, impression Graphite: 10-20% by weight, metal powder: 7-10% by weight of the basic composition, and relates to the basic refractory for Timing Ladle comprising 5-15% by weight of phenol resin relative to the total weight It is a technical point.

Description

Basic Refractories for Timing Ladles

The present invention relates to a basic refractory used in the slack-line of the Timing ladle, and more particularly to a basic refractory excellent in corrosion resistance and spalling resistance.

In general, the slag-line of the teaming ladle used in the steelmaking process of steelworks is severely damaged by slag, and the sidewalls except the slag-line are significantly damaged compared to other parts, so that the slag-line is balanced for erosion balance. Only partly pays off. The brick used in the slack-line reacts with the slack. The brick used in the slack-line is constructed of basic mag-carbon bricks containing a large amount of carbon for the purpose of suppressing the reaction with the slack. As a result, the decarburized layer on the surface of the wall has been damaged in a layered manner.

Representative examples of the Timing Ladle basic refractory include the refractory materials disclosed in Japanese Patent Application Laid-Open No. Hei 6-321625 and Japanese Patent Application Laid-Open No. Hei 6-321626.

The refractory material described in (Pyeong) 6-321625 is related to MgO-C fluorine-based lead, characterized in that it represents a structure containing 10-50% by weight of MgO particles surrounded by a layer of pitch. The refractory material described in No. 1 relates to a MgO-C fluorine refractory brick having 10-50% by weight of MgO particles coated with MgO with a pitch of 1-5% by weight and the remaining MgO particles and carbon as the main raw materials. However, when the basic refractory is used in the Timing Ladle Slack-Line site, the corrosion resistance and spalling property are not improved in common, which is a problem in maintaining the life of the furnace body. Since this problem directly affects the life of the Timing Ladle, the steel industry is required to have a refractory against slack and excellent spalling resistance.

Accordingly, the present inventors have repeatedly conducted research and experiments to solve the problems of the prior art, and based on the results, the present invention proposes an aggregate of magnesia-zirconia synthetic clinker and aggregates and slacks. By suppressing the reaction of the alumina-magnesia-based spinel powder, and forming the bond part with a low-expansion spinel component to harden the expansion and inhibiting swelling. And it is to provide a low-expansion basic refractory resistant to spalling, an object thereof.

The present invention for achieving the above object is a magnesia-zirconia clinker containing 15-25% by weight of a zirconia component: 60-70% by weight, alumina-magnesia-based spinel: particle size of 10㎛ or less: 10-20% by weight, impression It relates to a basic refractory for Timing Ladle, which is composed of graphite: 10-20% by weight and metal powder: 7-10% by weight, and contains 5-15% by weight of phenol resin based on the total weight.

Hereinafter, the reason for component limitation of the basic refractory for teaming ladle is demonstrated.

First, the magnesia-zirconia clinker among the refractory components varies depending on the amount of magnesia and zirconia, and the magnesia-zirconia clinker used in the present invention preferably uses a magnesia-zirconia clinker containing 15-25% by weight of zirconia. Do. The reason is that when the amount of zirconia is 15% by weight or less, there is no effect of suppressing the reaction between the aggregate and the slag, and when 25% by weight or more, the melting point of the aggregate decreases and the erosion by the slag is severe. In addition, the magnesia-zirconia-clinker including zirconia as described above is preferably contained in the range of 60-70% by weight, the reason is that when less than 60% by weight is less erosion effect due to slack, severe erosion, 70% by weight If it is more than%, the amount is excessive, the sintering is not good, so the hot strength is small and the structure is not dense, which makes the use unsuitable.

The alumina-magnesia-based spinel fine powder forms an interface between aggregates, that is, a strong low-expansion spinel bond having high refractory properties. Therefore, in order to play such a role, since reactivity is important, it is important to increase reactivity by using an ultrafine powder of 10 μm or less. At this time, the amount of spinel used is less than 10% by weight, so the effect of improving spalling is less. When the amount of used is 20% by weight or more, the melting point of the joining part is lowered, and the joining part is preliminarily melted. Do.

Low purity of the impression graphite is bad because it has a bad effect on erosion, it is preferable to use more than 95% natural acid. Such graphite reacts with phenol resin at high temperature to form a strong carbon bond, but the addition amount is less than 10% by weight of the anti-infiltration effect of the graphite, when the amount is more than 20% by weight of excessive graphite amount when molding Since cracks are inadequate, it is preferable to add in a range of 10 to 20% by weight.

The metal powder is used to prevent oxidation, and it is preferable to use one selected from Al, Mg-Al, Si, SiC, Al-Si, Al-SiC, Mg-Al-Si, and Mg-Al-SiC groups. Do. When the added amount of the metal powder is less than 7% by weight, the antioxidant effect is small, and when the amount of use is 10% by weight or more, it is excessive to produce a low melting point material and becomes excessively sintered so that erosion is severe, so it is added in the range of 7 to 10% by weight. It is desirable to.

It is preferable to add 5-15% by weight of the phenol resin as a binder to the basic composition as described above, because the amount is not used at 5% by weight or less due to low ambient temperature strength, it is unsuitable, If the amount is more than 15% by weight, the amount of use is excessive, and when used as a crack during drying, it is severely eroded by penetration of molten steel.

Hereinafter, the present invention will be described in detail through examples.

EXAMPLE

Each component of the basic refractory having a composition ratio as shown in Table 1 was kneaded and kneaded to form a brick in a hydraulic press and cured for 12 hours. This was cut into a size of 40 × 40 × 160 mm to measure the room temperature strength, and then maintained at 1450 ℃ for 3 hours in an reducing atmosphere using an electric furnace to measure the plastic line change rate and volume specific gravity. The hot strength was measured at 1000 ° C. for 30 minutes using a hot strength tester to measure the bending strength. In the erosion test, a rotary erosion tester using oxygen-propane gas as a heat source was held at a temperature of 1,600 ° C for 3 hours, and then the erosion depth was measured after the slag was poured. The spalling properties were tested in a vacuum atmosphere using a high frequency heating spalling test apparatus to compare the fracture state of the specimens. As described above, the measurement result of the plastic line change rate, volume specific gravity, hot strength, spalling resistance, and erosion resistance was measured and shown in Table 2 below. At this time, in the result of plastic line change rate, (+) value means expansion rate, and (-) value means shrinkage rate.

(Legend: ○ good, X defectiveness)

As can be seen from Table 1 and Table 2, Inventive Example (1-6), which satisfies the scope of the present invention, was particularly excellent in hot strength, spalling resistance, and erosion resistance compared to the comparative example. On the contrary, Comparative Example (1) in which the amount of magnesia-zirconia clinker is less than the range of the present invention has a low amount of aggregate, and thus has severe erosion. In addition, Comparative Example (2) is a case where the amount of magnesia-zirconia clinker is larger than the range of the present invention, the amount of aggregate is large, the tissue is not dense and the hot strength is also small. In Comparative Example (3), when the spinel amount was less than the range of the present invention, the expansion ratio was large and the spalling resistance was also poor. In addition, in Comparative Example (4), when the amount of spinel is larger than the range of the present invention, cracks occur due to the decrease in the expansion rate of the aggregate interface due to oversintering, and the erosion is severe. Further, in Comparative Example (5), even when the amount of the drawn graphite was less than the range of the present invention, the slack penetration inhibitory effect was small, and erosion was severe. In Comparative Example (6), when the amount of drawn graphite was greater than the range of the present invention, the graphite amount was excessive, so that cracks occurred between the brick layers, the strength decreased due to poor sintering, and the erosion was severe. In Comparative Example (7), when the amount of metal powder used was small, the brick surface was oxidized and erosion was severe in the decarburized layer. In addition, in Comparative Example (8), the amount of metal powder used was greater than the range of the present invention, but the oxidation resistance was good, but the hot strength was small, and low melting point material was generated by melting of the metal powder, thus causing erosion.

As mentioned above, the present invention can provide a low-expansion basic refractory resistant to erosion and spalling through proper design of the refractory, and the refractory provided above has a useful effect that can be applied to Timing ladles.

Claims (2)

Magnesia-zirconia clinker containing 15-25% by weight of zirconia components: 60-70% by weight, alumina-magnesia-based spinel having a particle size of 10 μm or less: 10-20% by weight, graphite graphite: 10-20% by weight, metal Powder: A basic refractory for Timing Ladle, based on 7-10% by weight, containing 5-15% by weight of phenol resin based on the total weight. The basic refractory according to claim 1, wherein the metal powder is one selected from Al, Mg-Al, Si, SiC, Al-Si, Al-SiC, Mg-Al-Si, and Mg-Al-SiC.