KR101045969B1 - Furnace upbringing method using decarburization slag of converter itself - Google Patents

Abstract

The present invention removes impurities such as carbon contained in hot metal and scrap metal and removes impurities from the converter which is a facility for refining molten steel. The present invention relates to a method for growing a furnace using decarburization slag of the converter itself to coat the inside of the furnace.

To this end, the present invention is a method for nurturing the inside of the furnace of the converter which is a facility for receiving molten iron to perform decarburization and refining, the molten steel is removed from the converter after the decarburization is completed, and the remaining slag is not discharged. The present invention provides a furnace body growth method using decarburization slag of a converter itself, by adjusting the dolomite input amount according to the carbon content of the molten steel, and reusing the entire amount of residual slag in the furnace body coating.

As described above, the present invention can foster the upper and the loading side of the most vulnerable body, the charging side, and the abdomen of the body, so that the target body can be used, which can contribute to cost reduction and productivity improvement.

Converter, decarburized slag, furnace growth, dolomite, magnesium oxide, iron oxide

Description

METHOD FOR REARING CONVERTER BODY USING THE DECARBONIZING SLAG REMAINED IN THE CONVERTER}

Figure 1 is a comparison of the conventional furnace body growth method and the furnace body growth method of the present invention.

The present invention relates to a method for growing a furnace using decarburization slag of the converter itself, and more specifically, a converter that is a facility for refining molten steel by removing impurities such as carbon contained in charged hot metal and scrap metal. The present invention relates to a furnace body growing method using the decarburizing slag of the converter itself which coats the inside of the furnace body without using any slag remaining in the furnace after tapping molten steel from the furnace.

Typically, the converter blowing operation is divided into a flat blowing operation and a decarbonizing operation.

The carbonation method is a method of oxidizing most of the carbon, about 4.5% by weight, of molten iron contained in the converter during the drilling, and refining the end point carbon at 0.04% by weight to 0.10% by weight or less. Legal operation is a method of leaving a certain amount (more than 0.1% by weight) of carbon, which is about 4.5% by weight of the molten iron contained in the converter.

The present invention is directed to the decarburization operation, which leaves a certain amount of carbon in the molten iron accommodated in the converter.

That is, the decarburization operation is absolutely advantageous for furnace coating because of good cleanliness of refined steel, low T.Fe (iron oxide) content in slag, high magnesium oxide (MgO), and low viscosity in slag. In the method, dolomite [Dolomite-CaMg (CO ₃ ) ₂ ], which is a coating agent, was not separately inputted, but the dolomite was added to the slag amount of 4.0㎏ / TS in the range of 0.9-1.9㎏ / TS to coat the furnace body. .

This furnace coating method is not only partial coating but also unsatisfactory use of the valuable oil components of slag, oversaturation or poor slag refining during the treatment, which leads to the increase of the use of solvents, which is disadvantageous to the furnace body. It has also become an environmental pollution source.

In the case of carrying out the converter operation by acquiring the general molten iron or the Tallinn molten iron, it is necessary to inject excessive oxygen into the molten iron to solve the heat source shortage caused by the low content of silicon (Si) in the molten iron or the low molten iron temperature. This heavy blowing of coral reduces the cleanliness of the refined molten steel.

In addition, such heavy oxygen injection has a high end point oxygen concentration in molten steel, and high-temperature slag not only increases the furnace erosion rate but also increases the amount of deoxidizer used, lowers the error rate of ferroalloy, decreases the tapping yield and increases the T.Fe in the slag. It has a problem such as delay.

That is, according to the prior art, the slag is not completely cured even after 3-6 times of dolomite injecting 0.5 ~ 1.9㎏ / TS of dolomite into the 4.0kg / TS of slag remaining in the converter. Even when / TS is added, the furnace coating time is long, and the cured residual slag is cured in the form of agglomerates and is only partially coating the furnace body.

As a method for solving the problems of the prior art, since the T.Fe in the slag is 0.18 to 0.20% by weight, magnesium oxide (MgO) is 0.98% to 1.03% by weight when the end point carbon concentration is 0.1 ~ 0.15% by weight. In accordance with this, dolomite is added at 0.10㎏ / TS, but this is extremely disadvantageous for desalination of molten steel, and the amount of residual slag generated during the drilling operation is generally generated in a relatively large amount of about 8-12㎏ / TS. .

As another furnace coating method, after decarburization operation, 2 ~ 4 tons of residual slag in the furnace is left, and dolomite is added 2 ~ 3 times with proper amount of dolomite, and then slag coating is performed. Not only is the efficiency lowered, but more dolomite is used than necessary, which increases the amount of side materials and can play a detrimental role in the desalination during the drilling.

In order to solve the above problems of the prior art, the present invention is the converter itself to fully utilize the valuable components in the slag by using the entire amount without exclusion of the residual slag that was previously operated in the converter blow operation in the decarburization operation The purpose of the present invention is to provide a method for fostering furnace bodies using decarburized slag.

In order to achieve the above object, the present invention is a method for nurturing the inside of the furnace of the converter which is a facility for accommodating molten iron to perform decarburization work, the decarburization work is completed and the molten steel is pulled out from the converter, and then remaining It provides a furnace body growth method using the decarburization slag of the converter itself, by adjusting the dolomite input amount according to the carbon content of the molten steel to be reused in the furnace body coating without excluding the slag.

In the present invention, when the carbon content of the molten steel is in the range of 0.1 ~ 0.15% by weight dolomite (250 to 380 kg per ton of residual slag), when the carbon content of the molten steel in the range of 0.16 to 0.20% by weight Dolomite ranges from 150 to 300 kg per ton of residual slag and carbon content of tungsten steel is 0.20 to 0.25% by weight. Dolomite ranges from 50 to 200 kg per ton of residual slag and carbon content of tungsten steel is 0.26 to 0.30% by weight. When the dolomite is put in the range of 0 ~ 100kg to provide a furnace body development method using the decarburization slag of the converter itself, characterized in that the entire amount of residual slag is reused in the furnace body coating.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated in detail.

In the present invention, the content of T.Fe in slag is lowered to 20% or less due to the lower end of the furnace converter catch carbon and the end point low temperature operation, so that the viscosity increases in the slag and becomes slag without fluidity. After finishing the tapping, the coating is filled with slag only to fill the internal melted portion of the converter. Rather than using a hot spray or kneader material, the inside of the furnace body is degassed using decarburized slag after the tapping is completed. When grown, the surface thickness is grown to a better level.

As described above, the molten steel refining operation of the converter is stably secured the content of the end point P, the first charge after the full catch carbon (decarburization) operation of the low temperature ash, the total amount of slag After refining, the second charge (Second Charge) is dolomite injecting a part of the coating after coating, some remain to coat the furnace body, and then the main raw material is scrap metal and molten iron It is a repetitive process of tapping and removing work after the drilling work.

The present invention is a method of applying the slag coating using the whole amount without exclusion of the residual slag that was operated last time after the converter blow operation performed by the catch carbon method, the content of iron oxide in the slag varies depending on the end point carbon and accordingly magnesium oxide ( By using different MgO) content and viscosity of slag, dolomite is applied differently according to the end point carbon content (wt%) of molten steel, so that it is used for the whole coating without slag.

As shown in Table 1, the amount of iron oxide (T.Fe) and magnesium oxide (MgO) according to the weight of the end point carbon is 17-20% by weight and the amount of magnesium oxide when the end point carbon is 0.1% by weight. When the end carbon is 0.2% by weight, about 9-11% by weight, the amount of iron oxide is 15-18% by weight, the amount of magnesium oxide is about 10-12% by weight, and when the endpoint carbon is 0.3% by weight, the amount of iron oxide is 11-15 The weight% and the amount of magnesium oxide is about 11 ~ 13% by weight, which varies slightly depending on the operating conditions.

Depending on the amount of iron oxide and magnesium oxide, the amount of dolomite is gradually added to 0 ~ 500㎏ to grow the furnace body by slag coating, which is a valuable component such as MgO present in the furnace body after the first charge and second charge operation. Since the amount is divided into justifiable amount, saturated, and supersaturated, dolomite is added to coat the inside of the furnace body according to the carbon content according to the previous decarburization.

Hereinafter, numerical limitations of the present invention will be described.

First, when the carbon content of the molten steel is in the range of 0.1 ~ 0.15% by weight dolomite is limited to 250 ~ 380 kg per ton of residual slag. When the end point carbon content is less than 0.1% by weight, iron oxide (T.Fe) is less than 20% by weight and magnesium oxide (MgO) is less than 8% by weight. In order to utilize the utility value, the end point carbon content range was based on 0.1 ~ 0.15% by weight.In this case, limiting the input of dolomite to 250 ~ 380kg per ton of residual slag is required for residual slag in 100 ton grade converter. It is because the effect of slag MgO component and dolomite MgO component on the furnace body is the most useful range when 2 to 4 ton remains, and it is calculated in the range of 7 to 9% by weight of slag. Therefore, dolomite is introduced at 250 to 380 kg per ton of residual slag as a result of the calculation.

When the carbon content of the molten steel is in the range of 0.16 to 0.20% by weight, the dolomite is limited to 150 to 300 kg per ton of residual slag. This range and dolomite input amount were selected in consideration of the furnace growth rate, the number of times of hard work, the MgO component and the T.Fe component identified in the slag component, and the input calculation method used the above-mentioned carbon 0.1 ~ 0.15. Same as the weight percent range.

Dolomite was selected from 50 to 200 kg per ton of residual slag when the carbon content of the molten steel was in the range of 0.20 to 0.25% by weight. In this case, the most suitable MgO component for the furnace body and the effect on the refining operation when the residual slag was used In consideration of this, the input amount was determined based on the data from the comparative analysis in Table 1, and the effect of slag MgO component and dolomite MgO component on the furnace body was selected as the most suitable range.

In addition, when the carbon content of the molten steel is in the range of 0.26 ~ 0.30% by weight, dolomite is added in the range of 0 to 100 kg, which is also determined based on the data from the comparative analysis in Table 1, and the slag has The effect of MgO component and dolomite containing MgO component on the furnace body was selected as the most useful range.

Hereinafter, the operation of the present invention in detail through examples.

After the completion of the blow at 100 ton converter, dolomite was added according to the end point carbon, slag coating was carried out by tilting the converter 2-4 times, and then the protective quicklime was added.

Table 1 shows the state of the slag coating method of the prior art and the present invention according to the end point carbon.

[Comparative Example 1] in Figure 1 shows the hot spray (Spray: Water + Air + MgO) to the locally damaged parts of the furnace body, 300 to 500 kg of magnesium oxide through the machine to prevent the diffusion of the lead and surrounding erosion Or evenly spray localized damage. In [Comparative Example 2], a kneader material is added to the fire retardant and damaged parts of the furnace to cultivate the furnace with a curing time of 60 minutes or more at 1 ton and 120 minutes at 2 tons. Due to the work required, there are disadvantages of process waiting, production decrease, and cost increase.

4 to 5 tons of residual slag containing 11% by weight of magnesium oxide (MgO) as a valuable component in residual slag according to the content of the end point carbon, except for the same method as in Comparative Example 1 and Comparative Example 2 described above. By using the whole amount to tilt the furnace body two or three times, the spalling part from the tapping side, the upper charging side, and the abdomen bottom, which is the weak body, between the lead and the lead, and the surface of the lead as shown in Table 1 The growth of 10-60 mm could be confirmed with the naked eye, and the state of no-growth was extremely good. In particular, it is possible to cultivate the upper part, the loading side, and the abdomen abdomen of the most weak side of the body, so that the target body can be used, and it can contribute to cost reduction and productivity improvement.                     

As described above, in the present invention, the amount of dolomite was added to the furnace body coating by adding the amount of dolomite in consideration of the amounts of iron oxide and magnesium oxide according to the carbon content of the molten steel dropped after the converter operation. Through this development method, a well-developed layer was formed between the spalling part from the tapping side, the upper charging side, and the abdomen bottom, the soft and soft wires, and the surface of the soft body. And the charging side and the abdomen abdomen can be raised, the target furnace can be used, and it can contribute to cost reduction and productivity improvement.

Claims (2)

In the method of raising the inside of the furnace body of the converter, which is a facility for receiving molten iron and decarburization work, After the decarburization and refining operation is completed, the molten steel is removed from the converter, and then the doped slag is removed from the slag, and when the carbon content of the molten steel is in the range of 0.1 to 0.15% by weight, dolomite is divided into 250 to 1 ton 380 ㎏, dolomite per ton of slag when the carbon content of the tumbled molten steel is in the range of 0.16 ~ 0.20% by weight, 150 ~ 300 kg per ton of residual slag, when the carbon content of the tumbled steel is in the range of 0.20 ~ 0.25% by weight When the carbon content of the molten steel is in the range of 50 to 200 kg and 0.26 to 0.30 wt%, dolomite is reused in the furnace coating by adjusting the input amount in the range of 0 to 100 kg per ton of residual slag. A method of growing a furnace using decarburized slag of a converter. delete

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