KR101552142B1 - Agent for dephosphorization and treatment method of molten metal using the same - Google Patents

Abstract

The present invention relates to a method and apparatus for processing molten iron, comprising the steps of: preparing a talline material containing Mg-smelting slag; Introducing the talline material into a container; Charging molten iron into the vessel; And a step of blowing oxygen into the vessel, wherein phosphorus (P) contained in molten iron such as molten iron, molten steel and the like can be quickly removed.

Description

[0001] The present invention relates to a method for treating molten metal,

The present invention relates to a talline material and a molten iron treatment method using the same, and more particularly, to a talline material capable of rapidly removing phosphorus (P) contained in molten iron such as molten iron, molten steel, will be.

In general, the phosphorus (P) component contained in molten steel is segregated in the cast steel during continuous casting, causing quality defects, and particularly cracking of the material under extreme environments, adversely affecting the product. As a result, under extreme conditions, materials such as pressure vessels and line pipes are mainly used for ultra-low-strength steels that are resistant to stress cracking and cracking due to hydrogen organic cracking and sulfides.

On the other hand, the steelmaking process proceeds in the order of the iron pre-treatment process, the converter refining process, the secondary refining process, and the continuous casting process.

In the converter refining process, hot metal and scrap are charged into the converter and high-purity oxygen (O ₂ ) gas is blown through the lance to convert the carbon and impurities in the charcoal into CO The molten steel from which the impurities are removed through this process is called molten steel.

The impure elements in the wire are subjected to the oxidation reaction as shown in the following reaction formulas 1 to 5 with pure oxygen gas to be blown.

(Scheme 1)

_{[C] + 1/2 O 2 =} CO (g)

(Scheme 2)

_{[Si] + O 2 = SiO} 2

(Scheme 3)

_{[Mn] + 1/2 O 2 =} MnO

(Scheme 4)

_{[Fe] + 1/2 O 2 =} FeO

(Scheme 5)

2 [P] + 5/2 O ₂ = P ₂ O ₅

In the reaction scheme 1, carbon is oxidized into carbon monoxide (CO) to be removed in a gaseous state, and the reaction formulas 2 to 5 are present in the slag layer as the additives to be added during the conversion operation are consumed. The slag layer thus formed actively reacts with the molten iron by stirring action by the impact energy of the off gas (N ₂ , Ar) and pure oxygen to stably remove the impurities in the molten iron, and in particular to remove and stabilize phosphorus It plays a very important role.

On the other hand, the content of phosphorus (P) in the blast furnace currently being discharged from the blast furnace is about 0.1 ~ 0.2%, the phosphorus content of the usual product is 0.015% and the content of phosphorus is 0.008% or less. However, as the use of low - cost raw materials is expanded, phosphorus content in charcoal is expected to increase further. Phosphorus (P) is mainly removed from converter or converter tallin because it is removed by using basic flux such as burnt lime in an oxidizing atmosphere. However, since the talline efficiency using the basic flux is not sufficient, additional efforts such as changing the physical properties of the slag in a certain period of time are required. However, when the concentration of phosphorus is increased when the raw material is used at a low cost, the processing time of the converter and talline is increased, resulting in a decrease in productivity and an increase in the processing cost due to an increase in the use of raw materials such as quicklime have. In addition, there is also a problem that the phenomenon that phosphorus is removed from charcoal by the characteristic of thermodynamics occurs in the converter.

KR 2012-0070675A KR 2010-97905A

The present invention provides a talline material capable of rapidly removing phosphorus (P) components contained in molten iron and a method for treating molten iron using the same.

The present invention provides a talline material capable of shortening the processing time of molten iron and improving productivity, and a method for treating molten iron using the same.

The talline material according to an embodiment of the present invention is a talline material that removes phosphorus contained in molten iron and includes a by-product which is produced by heating a single light including dolomite ore powder and silicon (SiO ₂ ) to reduce Mg, by-products can include di-calcium silicate (2CaOSiO _2, C2S).

The by-product can be formed into a lump after being crushed.

The talline material may further include quicklime.

The by-product and the quicklime may have a weight ratio of 1: 2 to 3.

A method for treating molten iron according to an embodiment of the present invention is a method for treating molten iron, comprising the steps of: preparing a talline material containing Mg-smelting slag; Introducing the talline material into a container; Charging molten iron into the vessel; And injecting oxygen into the vessel.

The process of preparing the tallin material including the Mg-smelting slag may include the steps of preparing Mg-smelting slag generated in the process of reducing Mg in the dolomite ore; Crushing the Mg-smelting slag; And a process of making the crushed Mg-smelting slag into a mass.

The Mg-smelting slag may comprise a dicalcium silicate (2CaOSiO ₂ ).

The talline material may further include quicklime.

The Mg-smelting slag may be added in an amount of 0.1 to 0.5 wt% based on the weight of the molten iron.

The weight ratio of the Mg smelting slag and the quicklime may be 1: 2 to 3.

The phosphorus component in the molten iron is formed by reacting tricalcium phosphate (3CaOP ₂ O ₅ ) formed by the reaction of SiO ₂ and CaO contained in the molten iron and a solid solution by reaction of the di-calcium silicate contained in the Mg- .

The molten iron may be molten iron or molten steel.

The talline material and the method for treating molten iron using the same according to the embodiment of the present invention can quickly remove phosphorus (P) contained in molten iron such as molten iron or molten steel. That is, by directly feeding steelmaking by-products containing 2CaO-SiO ₂ (C2S) component generated in the talline reaction into the molten iron, the talline reaction can be accelerated and the bouillon phenomenon can be suppressed. Therefore, the processing time of the molten iron can be shortened to improve the productivity, and the production burden of high-grade products can be reduced. In addition, since the by-products generated in the steelmaking process are recycled as tallin materials, it is possible to reduce the production cost and the cost of processing the by-products, by replacing the existing quick lime used as tallin material.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart showing a process of processing molten iron using a molten iron processing method according to an embodiment of the present invention; FIG.
FIG. 2 is a photograph showing the state of the Mg-smelting slag applied to the molten iron treatment method according to the embodiment of the present invention
3 is a graph showing the results of X-ray diffraction (XRD) analysis of Mg-smelting slag.
FIG. 4 is a graph showing changes in silicon (Si) and phosphorus (P) concentrations in molten iron after the completion of culling according to the type of talline material.
FIG. 5 is a graph showing the relationship between the concentration of phosphorus in the molten iron and the amount of phosphorus emission according to the type of tallane.
6 is a graph showing the relationship between the concentration of carbon in the molten iron and the carbon concentration according to the type of talline material.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

The principle of removing phosphorus components in molten iron such as molten iron or molten steel is as follows. Here, an example of removing phosphorus in the charcoal is described.

Phosphorus produces P ₂ O ₅ through an oxidative gas blown into the molten iron through the reaction shown in the following reaction formula (1). The P ₂ O ₅ thus produced produces tricalcium phosphate (3CaOP ₂ O ₅ , hereinafter referred to as "C3P") through the reaction of calcium oxide (CaO) introduced into the molten iron with the following reaction formula ( ₂ ). SiO ₂ in the molten iron produces di-calcium silicate (2CaOSiO ₂ , hereinafter referred to as "C2S") through the reaction of the quicklime charged with molten iron and the reaction formula 3 shown below. At this time, C2S is produced smoothly as the concentration of CaO contained in the slag increases, that is, as the amount of CaO injected into the charcoal is increased. The C3P and C2S thus generated react with each other to form a solid solution (SS), thereby removing phosphorus in the charcoal.

[Reaction Scheme 1]

2 [P] + 5/2 O ₂ = P ₂ O ₅

[Reaction Scheme 2]

P ₂ O ₅ + 3CaO = 3CaOP ₂ O ₅ _C3P

[Reaction Scheme 3]

_{SiO 2 + 2CaO = 2CaOSiO 2 (} C2S)

[Reaction Scheme 4]

3CaOP ₂ O ₅ + 2CaOSiO ₂ = 3CaOP ₂ O ₅ -2CaOSiO ₂ (Solid Solution, SS)

In the present invention, by using such a principle, P ₂ O ₅ is added to the burnt lime without increasing the time for producing P ₂ O ₅ and the amount of burnt lime reacted with the oxidizing gas, The phosphorus component in the molten iron can be quickly removed by shortening the time during which the C2P is produced by the reaction.

FIG. 1 is a flowchart showing a process of processing molten iron using a molten iron processing method according to an embodiment of the present invention. FIG. 2 is a view showing a state of a Mg smelting slag applied to a molten iron processing method according to an embodiment of the present invention. And FIG. 3 is a graph showing the results of XRD (X-ray diffraction) analysis of Mg-smelting slag.

Referring to FIG. 1, a method for treating molten iron according to an embodiment of the present invention includes a step (S100) of preparing a tallin material containing Mg-smelting slag, a step (S110) of putting the tallin material into a container, A process of installing a charcoal (S120), a process of charging a charcoal into a converter (S130), a process of injecting oxygen into a converter (S140), and a process of opening a manufactured molten steel (S150).

Mg smelting slag is a primary byproduct in the process of reducing Mg in dolomite ore. When dolomite ore is crushed and mixed with silicon oxide (SiO ₂ ) to produce monochromate. When mono-chrome is heated to about 1200 ° C, Mg in mono-chrome is vaporized and discharged to the outside of monochromatic light. The Mg-smelting slag may be a by-product in the form of a by-product as shown in FIG. 2 (a) as a by-product after recovering the vaporized Mg, and may be melted to form a mass or powder. Since the Mg-smelting slag exists in various forms as described above, it can be used as the tallin material of the present invention by crushing the Mg-smelting slag and processing it into a mass like a brick shape. If the talline ash exists in powder form, the reaction efficiency with the molten iron may be increased. However, since the process efficiency is lowered due to the charging of charcoal and the blowing of oxygen, it is preferable to manufacture the material as bricks or the like.

The Mg-smelting slag has a composition ratio (% by weight) as shown in Table 1 below.

SiO ₂ CaO MgO MnO P ₂ O ₅ TiO ₂ T-Fe C S 21.5 48.2 25.5 ≪ 0.05 ≪ 0.05 ≪ 0.05 2.73 0.07 0.09

Referring to Table 1, the Mg smelting slag contains 25.5 wt% or more of MgO, 21.5 wt% of SiO ₂ , and 48.2 wt% of CaO. As a result of analyzing the Mg smelting slag by the XRD method, it was found that SiO ₂ and CaO exist in the 2SaOSiO ₂ (C2S) state in the Mg smelting slag as shown in FIG. Therefore, when the Mg smelting slag containing C2S is fed into the molten iron as a tallin material during the converter operation, the reaction time for generating C2S can be shortened and the talline reaction can be accelerated. In addition, P ₂ O ₅ produced by reacting with phosphorus (P) in the charcoal rapidly reacts with C ₂ S to produce 3CaOP ₂ O ₅ -2CaOSiO ₂ Generation of a solid solution can suppress or prevent the phenomenon that the phosphorus oxide (P ₂ O ₅ ) in the slag is reduced and reverted.

The Mg smelting slag induces a talline reaction by the contained C2S, and also contains a large amount of MgO, which is a converter refractory component, and can also serve to protect refractories of the converter.

The input amount of the Mg smelting slag may be about 0.1 to 0.5 wt% based on the weight of the molten iron charged in the converter. If the input amount of Mg-smelting slag is less than the suggested range, the desired talline effect can not be obtained. If the amount of Mg-smelting slag is larger than the suggested range, the slag can be controlled rapidly by the SiO ₂ contained in the Mg- There is a problem that it becomes difficult. Also, there is a problem that the amount of slag increases as silicon (Si) contained in the molten iron is consumed as SiO ₂ by oxygen.

For this reason, the talline material introduced into the converter can be mixed with calcium oxide (CaO) together with the Mg-smelting slag. At this time, the Mg smelting slag and the quicklime are added so as to have a weight of 1: 2 ~ 3, whereby the basicity of the slag can be effectively controlled as well as the increase of the talline effect.

When the talline material is prepared as described above, talline material including Mg smelting slag and quicklime is introduced into the converter. At this time, it is possible to add subsidiary materials such as light dolomite, sintered ore and fluorite together with Tallinn material.

When Tallin ash is charged into the converter, charcoal produced from a blast furnace, an electric furnace, etc. is provided and charged into the converter. At this time, the charcoal may be a pre-processed charcoal.

When the charcoal is charged, the lance placed on the upper part of the converter is lowered, and oxygen is supplied through the lance to refine the charcoal.

When oxygen is blown, silicon (Si) in the molten iron is to generate the SiO ₂ reacts with oxygen and generates C2S reacts with the calcium oxide (CaO) contained in Tallinn material. Among the Mg smelting slag contained in the talline material, C2S reacts with C3P generated by the reaction of phosphorus (P ₂ O ₅ ) produced by phosphorus in the molten iron with oxygen and calcium oxide (CaO) to form a C2S-C3P solid solution To form slag. Generally, when calcium oxide (CaO) is used as a talline material, silicon in the charcoal reacts with oxygen to produce SiO ₂ by oxygen injection, and SiO ₂ reacts with calcium oxide, which is again talline, to form C 2 S, It is possible to shorten the time required for generating C2S by introducing Mg smelting slag containing C2S into the tallin material, thereby improving the initial talline efficiency of the smelting. In addition, by adding CaO together with the Mg smelting slag, it is possible to continuously remove phosphorus in the molten iron during the refining process by continuously reacting SiO ₂ generated by the reaction between silicon in the molten iron and the blowing oxygen. By this reaction, the phosphorus component in the molten iron can be efficiently removed.

Thereafter, the blowing of oxygen is stopped, the molten steel produced by tilting the converter is introduced, and then moved to a place for a subsequent process.

Hereinafter, the results of analyzing the components of the molten iron after the primary smelting to confirm the refining ability of the talline material including the Mg smelting slag will be described.

FIG. 4 is a graph showing changes in silicon (Si) and phosphorus (P) concentrations in the molten iron after primary firing according to the type of talline material, and FIG. 5 is a graph showing changes in the concentration of silicon FIG. 6 is a graph showing the relationship between phosphorus concentration and carbon concentration. FIG.

Figs. 4 to 6 show the results of analysis of the components in the charcoal when the converter was operated using a tallinn material containing Mg-smelting slag and when the converter was used as tallin material alone with calcium oxide (CaO). Indicates the case where the quicklime is used as a tallin material alone, and (2) shows a case where a talline material containing Mg-smelting slag is used.

FIG. 4 is a graph showing changes in phosphorus concentration and silicon concentration in the charcoal by collecting charcoal at predetermined time intervals. From the right to the left in the graph, it is shown that the winding time increases. Referring to FIG. 4, it can be seen that, in the case of using the talline material including Mg-smelting slag and the activated lime alone, the phosphorus concentration and the silicon concentration decrease with the progress of the curing time. However, it can be seen that the phosphorus concentration of the quicklime in the charcoal sampled at a similar time was higher than that of the charcoal using the talline material containing Mg-smelting slag. This shows that when the talline material containing Mg-smelting slag is used, the generation time of C 2 S in the Mg-smelting slag is shortened and the phosphorus component is effectively removed. At this time, silicon is produced as SiO ₂ by the blowing of oxygen and its concentration is decreased.

Referring to FIG. 5, it can be seen that, in the case where oxygen is blown into the furnace under similar conditions, for example, at a flow rate, the molten iron content in the molten iron is lower than that in the case of molten iron charged with talline material containing Mg smelting slag Able to know.

Also, referring to FIG. 6, lower phosphorus concentration was measured in the case of using talline material containing Mg-smelting slag than when using activated lime alone as talline material after completion of the primary smelting. Here, the carbon concentration in the molten iron is removed from the mid-tune period, so that the carbon concentration is relatively high. On the other hand, when the talline material containing Mg-smelting slag is used, the phosphorus concentration is measured to be low. .

Thus, when Mg smelting slag containing dicalcium silicate (C2S) is used as the tallin material, the talline reaction can be accelerated at the beginning of the molten iron shunting, and phosphorus is converted into the stable C2S-C3P form, Can also be suppressed.

Herein, the contents of removing the phosphorus component from the molten iron introduced from the blast furnace or the electric furnace have been described, but the above-described apparatus and method can be similarly applied to remove the phosphorus component in the molten steel subjected to the refining of the converter.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

Claims (12)

A talline material for removing phosphorus contained in molten iron,
By-products containing dolomite ore powder and a silicon oxide (SiO ₂₎ was dicalcium silicate (2CaOSiO _2, C2S) by heating reduction of the Mg Briquetting, including; And
Quicklime;
Wherein the by-product and the quicklime have a weight ratio of 1: 2 to 3. The method according to claim 1,
Wherein the by-product is formed into a mass after being crushed. delete delete As a method for treating molten iron,
Preparing dolomite ore and silicon oxide to produce mono-chrome, and heating the mono-chrome to vaporize Mg in mono-Mg to prepare Mg-smelting slag containing di-calcium silicate (2CaOSiO ₂ );
Crushing the Mg-smelting slag to prepare a brick-shaped talline material;
Introducing the talline material into a container;
Charging molten iron into the vessel; And
Injecting oxygen into the vessel;
/ RTI >
The components in the molten iron forms a solid solution with tricalcium phosphate (3CaOP ₂ O _5), and a reaction of the dicalcium silicate contained in the Mg Slag formed by the reaction of the SiO ₂ and CaO contained in the molten iron to remove ≪ / RTI > delete delete The method of claim 5,
Wherein the talline material further comprises quicklime. The method of claim 8,
Wherein the Mg smelting slag is charged in an amount of 0.1 to 0.5 wt% based on the weight of the molten iron. The method of claim 9,
Wherein the weight ratio of the Mg smelting slag to the quicklime is 1: 2 to 3. delete The method of claim 5,
Wherein the molten iron is molten iron or molten steel.

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