KR20050092498A - Acceleration material of slag making and fabrication method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a goods promoter used to promote slagmaking as a fluorspar substitute in a steelmaking process. It is to provide a new slag smelting accelerator that does not discharge. To this end, the present invention is ladle slag (ladle slag); And either one or both of limestone (CaCO ₃ ) and aluminum, followed by compression molding by a molding method such as briquetting or pelletizing to prepare a goods promoter.

Description

Acceleration material of slag and manufacturing method thereof

The present invention relates to a substitute for fluorspar used for the purpose of promoting slag refining in a steelmaking process, and more particularly, mixing and forming one or both of limestone and aluminum in steelmaking ladle slag. It is related with the slag goods promoter of the steelmaking process manufactured by making it, and its manufacturing method.

In general, when refining steel in a steelmaking process during the steelmaking process, slag is formed on the surface of the molten steel, a multicomponent material composed of a metal or a nonmetal oxide.

Representative slag composition is CaO-SiO ₂ -Fe _x O type. Especially, CaO added during the initial refining process produces high melting point 2CaO · SiO ₂ on the surface of molten steel, resulting in temporary material stagnation. It may also cause, or inadvertently, throwing, a phenomenon in which slag and molten steel in the furnace are ejected out of the furnace.

In addition, in ladle refining for steel refining, the high melting point slag composed of CaO-SiO ₂ -Al ₂ O ₃ system keeps the molten state of limestone or iron ore and the slag goods Becomes difficult. Therefore, in the steelmaking process, it is required to promote the goods of the slag and to prevent the slope.

In order to satisfy this demand, fluorite (CaF ₂ ) was conventionally added. Fluorite dissociates into Ca ²⁺ and 2F ⁻ ions in the slag, which weakens the bond between the silicate network in the slag and the high melting point 2CaOSiO ₂ layer formed on the surface of the CaO By destroying, it promotes the regeneration of slag and at the same time improves fluidity, speeds up the refining reaction, and also acts as a desulfurization and dephosphorizing agent. In particular, F ^- ions have been known to effectively destroy silicate networks because of their small ionic radius and high electronegativity.

However, fluorspar has a problem of generating HF gas by reacting with moisture and SiO ₂ as shown in Schemes 1 and 2 below.

CaF ₂ + H ₂ O → CaO + 2HF (g)

2CaF ₂ + SiO ₂ → 2CaO + SiF ₄ ,

SiF ₄ + 2H ₂ O → SiO ₂ + 4HF (g)

HF gas can impair lung, liver, and kidneys and can cause breathing problems and skin diseases. In addition, erosion of the refractory due to excessive addition is also a problem. As a result, countries around the world regulate the emission of fluorspar and fluorine and limit their use, thus developing and using alternatives to fluorspar.

Such fluorspar substitutes include borate, bauxite, synthetic flux, etc., but these substitutes are less effective when the same amount of fluorspar is used. , Or even if the effect is similar, there is a problem such as the terminal Fe content (T.Fe: total Fe) is low and the slag amount is rapidly increased.

In order to solve this problem, iron ore in North America or Europe is mainly used as a converter material for the converter process, but in this case, it is difficult to control the components.

Alternatively, fluorspar and alternatives can be used simultaneously, in which case there is a fundamental limit to the reduction of fluorspar usage.

The present invention has been made to solve the conventional problems as described above, the object of the present invention is to provide a new slag smelting accelerator that is low in manufacturing cost, excellent performance as a fluorspar substitute, and does not emit substances harmful to the environment.

Another object of the present invention is to promote the production of slag during the steelmaking process to produce a stable slag.

In order to achieve the above object, the present invention provides a fluorite substitute of briquette and pellet type, which replaces fluorite in slag material accelerator used in the steelmaking process and has a low melting point and easy storage. do.

In the present invention, as a fluorspar substitute in the steelmaking process is used to promote the slag making of the slag, ladle slag (ladle slag); And a limestone (CaCO ₃ ) and aluminum or any one or both.

The goods promoter may then comprise 30-70% by weight of ladle slag, 10-40% by weight of limestone, and 5-30% by weight of aluminum, or 50-90% by weight of ladle slag, and in limestone and aluminum It may also comprise 10-50% by weight of either.

The ladle slag here preferably has a composition comprising 30-60% by weight of CaO, 20-50% by weight of Al ₂ O ₃ , 10% by weight or less of SiO ₂ , and the balance of unavoidable impurities.

The goods promoter may be molded by a briquetting or pelletizing method to have a particle diameter of 5 to 50 mm.

As such, a method of manufacturing a goods accelerator used to promote slag goods as a fluorspar substitute in the steelmaking process, the present invention comprises the steps of mixing the ladle slag with any one or both of limestone (CaCO ₃ ) and aluminum; The product promoter is prepared by the step of molding the mixture by briquetting or pelletizing.

In the mixing step, 30-70% by weight ladle slag, 10-40% by weight limestone, and 5-30% by weight aluminum may be mixed, or 50-90% by weight ladle slag, and any of limestone and aluminum One can also mix 10-50% by weight.

In the molding step, it is preferable to add water and a binder, followed by molding. After the molding step, it is preferable to further include drying at a temperature of 100-300 ° C.

Hereinafter, the slag goods promoter according to the present invention and a method for producing the same will be described in detail.

In the present invention, by using a ladle slag and adding one or both of limestone (CaCO ₃ ) and aluminum to it, a goods accelerator for promoting slag making in the steelmaking process is provided. Manufacture. The goods promoter according to the present invention thus prepared is used as a fluorspar substitute to replace the existing fluorspar.

Steelmaking ladle slag used in the present invention is a pre-melted type, its melting point is low, the content of CaO is high, the recycling of resources and the generation of slag can be reduced, and the addition of limestone and aluminum to desulfurization and dephosphorization Can be made more active.

Steelmaking ladle slag used in the present invention is a composition of 30-60% by weight of CaO, 20-50% by weight of Al ₂ O ₃ , 10% by weight or less of SiO ₂ , and the remaining unavoidable impurities.

The use of these ladle slag shows the same level of delinquency as the fluorite and the use of quicklime can reduce the use of fluorspar. In addition, by reducing the slag generation by recycling the ladle slag generated as a by-product of the steelmaking process.

Ladle slag plays a role of improving the slag recyclability, and also excellent in absorbing inclusions to play the role of desulfurization and delineation.

Limestone plays a role in promoting desulfurization and delineation reactions, but adding too large a quantity lowers slag recyclability due to high melting point CaO and also deteriorates slag fluidity.

Aluminum serves to promote desulfurization in the desulfurization reaction shown in Scheme 3 below.

CaO + FeS → CaS + FeO (or O + Fe)

In the desulfurization reaction shown in Scheme 3, the conditions for promoting desulfurization are high concentrations of CaO and low concentrations of O (oxygen). To this end, the existing oxygen is removed using aluminum having excellent deoxidizing power. Therefore, aluminum promotes desulfurization by removing oxygen.

Therefore, the more ladle slag is used, the better the slag recyclability and the more limestone and aluminum are used, the higher the desulfurization and delinquency ability, but the increase in the amount of limestone and aluminum does not necessarily mean desulfurization and delinquency. It doesn't improve.

For example, if the content of the ladle slug is too small to reduce the ash capacity, even if the amount of limestone and aluminum is increased, the effect of desulfurization and dephosphorization improvement is small and the ash capacity is still difficult to improve.

More importantly, it is necessary to balance the relative content ratio between the amount of limestone and aluminum added and the amount of ladle slag used so as to be within an appropriate range. have.

In the case of using both limestone and aluminum according to an embodiment of the present invention, the goods accelerator of the present invention may include 30-70% by weight of ladle slag, 10-40% by weight of limestone, and 5-30% by weight of aluminum. It is possible to further improve the ability of fire, desulfurization and delinquency.

At this time, when the ladle slag is used at less than 30% by weight, the fire ability is relatively weak, and when it is used at an amount exceeding 70% by weight, the relative amount of limestone and aluminum is small so that desulfurization and dephosphorization are relatively weak.

The use of limestone in less than 10% by weight is relatively weak in desulfurization and delinquency, and in excess of 40% by weight of slag is relatively weak.

If the aluminum is used at less than 5% by weight, the desulfurization ability is relatively weak, and if the aluminum is used at more than 30% by weight, the slag ash is relatively weak.

In the case of using any one of limestone and aluminum according to another embodiment of the present invention, if the goods promoter of the present invention includes 50-90% by weight of ladle slag and 10-50% by weight of any one of limestone and aluminum, Recycling ability, desulfurization ability, and delinquency ability can be improved more.

In the case of using either limestone or aluminum as described above, the use of ladle slag at less than 50% by weight makes the ash less susceptible, and when it is used at more than 90% by weight, the relative amount of limestone and aluminum is used to desulfurize. And delinquency is relatively weak.

If less than 10% by weight of either limestone or aluminum is used, the desulfurization and delinquency is relatively weak, and when it is used at more than 50% by weight, the slag ash is relatively weak.

However, the present invention is not necessarily limited to the above-described composition ranges, and although it is relatively weak in the capability of dehydration, desulfurization, and delinquency, even if it is out of the range of the above-mentioned composition, it is not impossible to use it as a promoter for the reproduction. However, within the above-mentioned composition range, the recyclability, desulfurization ability, and delinquency ability are relatively better.

Water and a binder are added to the raw materials as described above, kneaded in a kneader, and then made into a size of 5 to 50 mm in a separate molding machine, dried, cooled, and then packaged and commercialized.

At this time, one example of the molding method may be a briquetting or pelletizing method, but is not necessarily limited to these methods, and various ceramic molding methods may be used, including briquetting or pelletizing.

An example of a drying method may be dried in a dryer at 100 ~ 300 ℃ in a heating furnace, but is not necessarily limited to this drying method.

In this way, commercialized goods accelerators can be used as fluorspar substitutes by satisfying the low melting point and high T.Fe (total Fe), which are global regulatory conditions for use as fluorspar substitutes in steel processing.

It is also an environmentally friendly product manufactured using steelmaking ladle slag and has the advantage of recycling resources. In addition, Briquette or Pellet products have the advantage of easy storage or utilization.

The following presents a preferred embodiment to aid the understanding of the present invention. However, the following examples are provided only to make the present invention easier to understand, and the present invention is not limited to the following examples.

<Example>

The fluorite substitute of the composition as shown in Table 1 was added to the converter and the ladle of 300 tons to observe the degree of ash, desulfurization and delinquency of the slag, and the results are shown in Tables 2 and 3.

That is, for each of Examples 1 to 8, which are fluorite substitutes prepared by adding limestone and / or aluminum to the ladle slag according to the present invention, and Comparative Examples 1 to 4 using fluorite, the composition, recyclability, and desulfurization Rate and thallin rate are shown in Tables 1-3.

Composition (wt%) Ladle slag Limestone aluminum fluorite Example 1 30 40 30 - Example 2 40 30 30 - Example 3 60 10 30 - Example 4 70 30 - - Example 5 20 40 40 - Example 6 65 5 30 - Example 7 65 32 3 - Example 8 80 10 10 - Comparative Example 1 - - 50 50 Comparative Example 2 - 20 40 40 Comparative Example 3 - 50 - 50 Comparative Example 4 - - - 100

◎: Excellent, ○: Good, △: Vulnerable division Ability Example 1 ○ Example 2 ◎ Example 3 ◎ Example 4 ○ Example 5 △ Example 6 ◎ Example 7 △ Example 8 △ Comparative Example 1 ○ Comparative Example 2 ○ Comparative Example 3 △ Comparative Example 4 ◎

division Initial S (% by weight) S (wt%) after refining Desulfurization Rate (%) Initial P (% by weight) P after refining (% by weight) Tallinn (%) Example 1 0.0115 0.0032 72% 0.101 0.030 70% Example 2 0.0115 0.0022 81% 0.100 0.017 83% Example 3 0.0114 0.0024 79% 0.103 0.021 80% Example 4 0.0115 0.0052 58% 0.099 0.026 74% Example 5 0.0115 0.0048 58% 0.102 0.036 65% Example 6 0.0121 0.0039 68% 0.102 0.034 67% Example 7 0.0115 0.0053 54% 0.101 0.023 77% Example 8 0.0116 0.0040 66% 0.104 0.029 72% Comparative Example 1 0.0113 0.0040 65% 0.100 0.031 69% Comparative Example 2 0.0114 0.0040 65% 0.095 0.024 75% Comparative Example 3 0.0114 0.0046 60% 0.100 0.030 70% Comparative Example 4 0.0115 0.0035 70% 0.102 0.020 80%

As shown in Tables 2 and 3, Examples 1 to 8 of the present invention showed more than equivalent level of recyclability, desulfurization rate, and delineation rate of Comparative Examples 1 to 4. In particular, in Examples 1 to 4 falling within the composition range suggested by the present invention, it was confirmed that the desulfurization rate or the delineation rate was better than that of Comparative Examples 1 to 3 in which fluorite was partially used without using ladle slag.

As described above, in the present invention, it is cured at a relatively low temperature by replacing fluorite, which is a slag recycling agent, and is environmentally friendly due to no environmental pollution caused by HF gas. Compared to the low and the effect does not fall, it is effective to provide a resource recycled fluorspar replacement.

In addition, when used together with quicklime as an additive of low melting point, active refining reaction is possible due to the promotion of the goods by increasing the dissolution rate of quicklime.

In addition, as a pre-melted type additive, its dissolution rate is fast, its ingredients are uniform, and it replaces fluorspar, saves the amount of limestone and iron ore used in the existing operation, and does not increase the amount of slag separately. It is characteristic.

Claims (8)

As a substitute for fluorspar in the steelmaking process, it is used to promote slagmaking. Ladle slag; And Either or both of limestone (CaCO ₃ ) and aluminum Goods promoter comprising a. The method of claim 1, The goods promoter comprises goods 30-70% by weight of the ladle slag, 10-40% by weight of the limestone, and 5-30% by weight of the aluminum. The method of claim 1, The goods accelerator, 50-90% by weight of the ladle slag, and 10-50% by weight of any one of the limestone and aluminum. The method according to any one of claims 1 to 3, The ladle slag comprises 30-60% by weight of CaO, 20-50% by weight of Al ₂ O ₃ , 10% by weight or less of SiO ₂ , and the residual unavoidable impurities. The method of claim 1, The goods promoter is a goods promoter molded to have a particle size of 5 ~ 50mm by briquetting or pelletizing method. The method of claim 5, Water and a binder are added during the molding, and the goods promoter is dried at a temperature of 100-300 ℃ after the molding. As a method of manufacturing a goods promoter used to promote slagmaking as a fluorspar substitute in the steelmaking process, Mixing the ladle slag with either or both of limestone (CaCO ₃ ) and aluminum; Forming the mixture by briquetting or pelletizing method. The method of claim 7, wherein In the mixing step, 30-70% by weight of the ladle slag, 10-40% by weight of the limestone, and 5-30% by weight of aluminum, or Or 50-90% by weight of the ladle slag, and 10-50% by weight of any one of the limestone and aluminum.