KR910008205B1 - Agent for controling the slag foaming - Google Patents

Abstract

A slag forming inhibitor in the removal of silicon for a molten iron is composed of at most 20 wt.% obsidian contg. at least 73 wt.% silica, 30-40 wt.% furnace sludge contg. at least 30 wt.% carbon, 20-40 wt.% paper sludge, and 10-20 wt.% refractory material contg. 60-65 wt.% MgO, 15-20 wt.% CaO and at most 20 wt.% clay.

Description

Degreasing slag forming inhibitor

1 is a schematic diagram for explaining the slag forming phenomenon.

2 is a graph showing the forming height for the inhibitor type.

The present invention relates to a de-silica slag forming inhibitor generated during the de-silicon treatment, and more particularly, to a de-silica slag forming inhibitor generated during the desulfurization treatment on the blast furnace column.

As shown in FIG. 1, the slag forming phenomenon includes carbon, silicon, and manganese in molten iron in which oxygen sources contained in the molten iron degreasing agent mill-scale and sintered ore. As a result of reaction with oxygen, oxygen source reacts with carbon to generate gas of CO or CO ₂ and oxygen source reacts with silicon and manganese to produce SiO ₂ , MnO and FeO, which are highly viscous slag. In other words, the gas of CO ₂ is not penetrated through these highly viscous slag and is trapped inside and consequently the slag layer is raised. Slag forming phenomena hinder the heat transfer between the slag layer and the molten metal layer during open hearth operation, and especially during molten metal degreasing, the slag overflows out of the repair vessel, resulting in a pressure drop or operation speed. It is a detrimental phenomenon that causes the lung to lower. In order to suppress the slag forming phenomenon and provide a normal repair of the molten iron during molten iron deregulation, several methods have been proposed. Conventional methods for suppressing slag foaming are largely classified into suppression methods in consideration of physical properties and reactivity of high viscosity slag and suppression by changing peripheral equipment. As a method of inhibiting slag physical properties, TiO ₂ is selected as a suitable material and its powder (ilmenite) is introduced into the slag forming layer to destroy the slag network structure and flames. There is a method of reducing the viscosity by reducing the FeO in the forming slag to Fe and O with the carbon component contained therein by using a (lumunous flame), a pitch, and the like.

However, these conventional techniques have the disadvantage of low efficiency and requiring additional equipment. In addition, a method of inducing weakening of the foam layer by inducing a change in slag composition using an inhibitor composed of wood powder and a small amount of binder as waste paper sludge and organic material discharged from a fireproof material and a paper pulp mill is Japan. Patent Publication No. 57-161017 discloses a rubber tire as a method of destroying the foam layer by remarkably strengthening the escape of the trapped gas in addition to the method of weakening the properties of the slag. The method of suppressing the forming of the refinery furnace in the furnace slag during or after refining has been proposed in Japanese Patent Laid-Open No. 59-133309, which has low efficiency, generates toxic gas, and changes the molten iron component. There are disadvantages to coming.

In addition, a method of injecting carbide (CaC ₂ ) into the foam layer while detecting the height of the foam layer by a change in electrical conductivity is disclosed in US Patent Nos. 4, 473 and 397. This is for the purpose of allowing the carbide to reduce the highly viscous FeO to induce the viscosity change of the slag to easily escape the gas in the foam layer, but there are disadvantages such as the cost of the blowing equipment and the conductivity measuring equipment. In addition to the above-described method for controlling slag properties, a method of separately removing slag generated by installing a separate slag induction path that induces slag forming by changing peripheral facilities is separately disclosed in Japanese Patent Laid-Open No. 60-228612. If the slag foaming phenomenon is observed during the repair of the charterer, there is a method of using the natural suppression of the foaming by temporarily changing the repair container, but these methods are only temporary measures and can be a continuous countermeasure. It is not there. On the other hand, there is an aluminum-based inhibitor, its slag forming inhibitory effect is good because it is currently used a lot, but the price is expensive, there is a problem in terms of economic burden. In general, aluminum-based inhibitors are "SYNLUX" (tm) under the trade name of Nippon Technics Co., Ltd. and its chemical composition is 56.2 wt% ash, 25.3 wt% fixed carbon, 13.0 wt% aluminum, and moisture. : 2.1 wt%, sulfur (S): 0.22 wt%. Accordingly, the present invention has been proposed based on the fact that the slag layer must be fixed in order to reduce the viscosity of the highly viscous slag and to suppress the continuous generation of foaming, and thus the sledger, obsidian, papermaking sludge and fire resistance It is to provide a foaming inhibitor prepared by mixing an appropriate amount of the material to suppress slag forming generated during molten iron degreasing treatment in the blast furnace column.

Hereinafter, the present invention will be described in detail.

The present invention provides a slag forming inhibitor for suppressing slag forming phenomenon generated during molten iron degreasing treatment, the slag forming inhibitor comprising: up to 20% by weight of obsidian containing at least 73% by weight of silica; 30-40% by weight blast furnace sludge containing at least 30% carbon; It relates to a desilica slag forming inhibitor comprising 20 to 40% by weight of papermaking sludge and 10 to 20% by weight of a refractory material. The obsidian (obsidian) is intended to expand the slug when trapped in the slag to capture the slag layer, blast furnace sludge to be a carbon source (resource) to reduce the viscosity of the high viscosity slag, Paper sludge and refractory materials are used in part because they can accelerate this reaction.

In particular, the obsidian serves to agglomerate slag by rapidly expanding its volume 5-6 times at a molten iron temperature of 1000 ° C. or more, and at this time, the temperature of the slag surface is slightly lowered, and thus the slag layer is fixed. If growth is suppressed, but the amount is 20% by weight or more, the obsidian scattered on the surface of the slag expands on the surface and promotes shaping, so the amount is preferably 20% by weight or less. Examples of chemical components for the obsidian and blast furnace sludge are shown in Tables 1 and 2, respectively.

TABLE 1

TABLE 2

In addition, an example of a preferred chemical component of the refractory material contains 60-65 wt% MgO powder, 15-20 wt% CaO powder and 20 wt% or less clay, and its particle size is 1 mm or less. Is preferred, and the components are generally used as stamping materials. In addition, an example of a preferable chemical component of the papermaking sludge is shown in Table 3 below, and the papermaking sludge is not limited thereto, and any papermaking sludge may be used as long as it is used in a slopping sedative.

TABLE 3

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

EXAMPLE

Graphite crucible was used as an indirect heating source in an induction melting furnace, and a magnesia crucible was installed therein to de-silify 15 kg of molten iron of 0.6 wt% [Si] to 600 g of millscale at a processing temperature of 1350 ° C. In order to suppress the foaming of the slag, the conventional inhibitor shown in Table 4, the inhibitor and the comparative material according to the present invention were added, respectively, and after 20 seconds, the foaming inhibitory activity of each was measured and shown in FIG.

TABLE 4

* Bentonite is included in refractory materials (Composition A).

Here, in order to prevent the natural suppression of the slag foaming by the reaction between the slag generated and the magnesia crucible before adding the inhibitor, a large amount of slag was generated in advance with a large amount of mill scale and sufficiently saturated on the crucible wall and used as an inhibitor. The constituents were first measured by obsidian and the remaining refractory materials, and mixed according to the composition table. As shown in FIG. 2, when no foaming inhibitor is added, the slag foaming height of 140 mm is used, and the slag foaming height of 110 ± 2 mm for the conventional material A, and 140 ± 3 and 135 for the comparative materials 1 and 2. Slag foam height of ± 3, and slag pitch height of 100 ± 3mm for invention materials B and C.

As described above, the present invention materials B and C have excellent slag forming inhibitory ability as compared with the conventional materials A and the comparative materials 1 and 2.

In addition, in the case of Inventive C, which merely increased the raw unit by 1.3 times with respect to Inventive B, the result is almost similar to the increase in the raw unit, which may help in setting an optimal raw unit of the inhibitor.

As described above, the present invention can not only have better slag foam suppression ability than the conventional inhibitor, but also can utilize the blast furnace sludge, which is a self-producing by-product of steel mill, so that the desulfurization slag suppressing agent having a cost reduction effect can be obtained. It can manufacture.

Claims (1)

Inhibitors for suppressing slag forming generated during soluble desulfurization treatment: Obsidian containing at least 73% by weight of silica: 20% by weight or less, blast furnace sludge containing at least 30% by weight of carbon: 30-40% by weight, converter Conventional paper sludge used as a sloping agent: 20-40% by weight, and refractory material containing 60-65% by weight MgO, 15-20% by weight CaO and up to 20% by weight clay: 10-20% De-slag forming agent, characterized in that the composition in%.

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