JPS62158812A - Manufacture of carburizing material for metallurgy - Google Patents

Abstract

PURPOSE:To manufacture carburizing material for efficiently adding carbon into steel making bath, by carrying out procedure in which binder is added to cokes fines and iron fines, these are mixed, heated and dehydrated, in one stage, then carrying out compacting and water content controlling. CONSTITUTION:The cokes fines 1 and the iron fines 1' of <=1mm particle size are intermittently and automatically charged from hoppers 3, 3' to a high speed mixer 5 having revolving blades 8, 22. Arranging ratio of the fines 1 and 1' is regulated to 10-60:90-40, and the fines 1' contains >=50wt% metallic Fe. Next, if necessary, the fines are heated, water is fed, binder (PDA, etc.) is added from a tank 12, these are stirred, mixed, melted at high temp. and rolled. At this time, water content in material is exhausted as vapor from an exhausting pipe 13. If mixing stage is ended, material is charged to a roll molding machine 20 having draining groove or a disk molding machine 21 providing dewatering grooe from a hopper 19, compacted to briquette. It is passed through a hot wind dryer 23 and the water contacted and hardness of the finished product dre controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a metallurgical recarburizer to be added to a metallurgical furnace, such as an electric furnace for steelmaking.

[Prior art]

Generally, when refining high carbon steel using a metallurgical furnace, such as an electric furnace for steelmaking, a recarburizer is used to adjust the carbon content during steelmaking. In this case, pig iron, lump coke, powdered coke, etc. are used as recarburizers, but although pig iron is a material with a high carbon yield as a recarburizer, its carbon content is low at about 4%, so the amount of addition is There is a disadvantage that the number of particles increases, and that they are bulky and large, resulting in a long dissolution reaction time and high cost. Furthermore, since both lump coke and powder coke have low specific gravity, they float to the surface of molten steel during steelmaking, resulting in a low carbon yield of 60 to 40 inches. Furthermore, when coke is used as a recarburizer, it has the disadvantage that it cannot be handled by the lifting magnet used for charging the main raw material because it has no magnetism, so a special charging device must be installed. It is also possible to use coke powder by blowing it into the injection pipe, but in addition to the drawbacks mentioned above, coke powder only reaches shallow parts of the molten steel, which is bad for the environment, and the carbon yield is still low. remains.

The present inventors filed a patent application No. 59-22939 for a metallurgical recarburizer that improves the drawbacks of these conventional recarburizers.

The above invention is based on the use of ultrafine coke powder generated in steel works, etc., which has limited use because of its fine particle size. This is a metallurgical recarburizer made by blending fine coke with a grain size of 1 or less and fine iron powder, adding a binder, mixing and molding. It is. This metallurgical recarburizer is a metallurgical recarburizer that can be used in metallurgical furnaces such as electric furnaces for steelmaking, has a high carbon yield, and can be handled with a lifting magnet or the like.

Generally, in order to make these metallurgical recarburized materials into briquettes or pellets, a series of steps are required: drying of the raw materials, crushing, mixing, adding a binder, heating and dehydration, compression molding, and moisture adjustment. It is also necessary to provide separate equipment for the husband and husband.
Equipment costs are high.

Furthermore, the metallurgical recarburizer includes fine coke with a particle size of 1 m or less and fine iron powder containing metallic F@, such as converter O.
Since it is a metallurgical recarburizer made of collected fine particles of iron such as G dust, the raw material fine coke and fine iron powder absorb a large amount of moisture during accumulation, and the moisture content fluctuates widely.
Furthermore, since fine iron powder contains metallic Fe, it is easily oxidized. Therefore, when manufacturing it using conventional methods, it is difficult to maintain uniform moisture, resulting in low crushing strength after molding. Since Fe has drawbacks such as not being able to be used effectively as an iron source, there has been a demand for the development of a method for producing these metallurgical recarburizers.

[Problem that the invention seeks to solve]

The present invention blends fine coke and fine iron powder with a particle size of 11111I or less and a high moisture content fluctuation, and completely adds a binder to the mixture, and has a high carbon yield when used in metallurgical furnaces such as electric furnaces for steelmaking, and is suitable for use in lifting magnets, etc. The purpose of the present invention is to provide a method for efficiently producing a metallurgical recarburizer that can be handled in a variety of ways.

[Means for solving problems]

In producing a metallurgical recarburizer consisting of fine coke powder and fine iron powder, the present inventors have developed a method for producing a strong briquette for coke as disclosed in Japanese Patent No. 980334 (Japanese Patent Publication No. 13441/1983). "methods and equipment used therein" (hereinafter referred to as "K")
, B is called a mixer. ), the steps in the conventional method for manufacturing recarburized materials are simplified as much as possible, and the five steps of drying raw materials, pulverization and mixing, addition of a binder, and heating and dehydration are performed in one step, followed by compression molding, The purpose is to manufacture a metallurgical recarburizer that adjusts moisture content. That is, the gist of the present invention is to use a mixture of fine coke with a particle size of 1+W or less and fine iron powder as a raw material, and to add a binder to the raw material to produce a recarburized material. The present invention is a method for producing a recarburized material for metallurgy, in which a series of steps of pulverization, addition of a binder, mixing, and heating and dehydration are performed in one step, followed by compression molding and moisture adjustment.

Furthermore, the blending ratio of raw material fine coke and fine iron powder is 10~
60: within the range of 90 to 40, the fine iron powder contains 50 weight or more of metallic F@, preferably converter OG dust, and the fine coke is preferably coke fire extinguishing equipment (CDQ) dust. be.

The binders added when mixing these raw materials are carboxylic methylcellulose (CMC), polyvinyl,
Selected from alcohol (poval), propane de asphalt (PDA), thermoplastic acrylic resin, thermosetting synthetic resin, starch, lignin, inorganic pentonite, cement, water glass, pitch, tar, and wood tar. 1 or 2 types, among which PDAe 1-10%
Or, polyvinyl alcohol is added and mixed in an amount of 20% or less.

When mixing these raw materials, adding one type selected from polyphosphoric acid, tannic acid, boric acid, etc. as a rust preventive agent can prevent oxidation of fine iron particles and make effective use of iron. It will be planned.

In addition, a mixer with high-speed stirring blades that mixes fine coke and fine iron powder supplies heat through a heat supply device and releases raw material moisture outside the mixer through indirect heating.
Also, when pulverizing in a mixer, water is added and water t-
adjust. In the process of adding a binder to these raw materials and molding the resulting mixture, it is recommended to use a roll-type molding machine with drainage grooves or a desk-type molding machine with dehydration grooves around the mold circumference for good metallurgical processing. Carbonaceous material is obtained.

[Effect]

Next, the method of the present invention will be explained based on the process diagram of the present invention shown in FIG.

In the coke manufacturing process of a steelworks, which normally has a moisture content of 5 to 10%, for example, 1 piece of fine coke of particle size -1 sushi and 1 piece of iron powder collected in a coke extinguishing equipment (CDQ), etc. d) into the respective air flow conveying hoppers 3 and 3'. These - 1m particle size fine coke 1
and the required amount of carburization of fine iron powder 1' and the crushing strength after molding,
Depending on the molding specific gravity, a high-speed rotating mixer (K
Raw materials are fed into mixer B) 5 intermittently and automatically. In this case, the tip of the pneumatic tube is sealed when the raw material is introduced. A temperature meter 6 measures the internal temperature of the KB mixer 5, and rotary blades 8 and 2 coaxially attached to the KB mixer 5 measure the internal temperature.
2 is rotated at high speed by power 16 through an acceleration/deceleration gear 17.

The raw material inside the KBi mixer is pulverized by blades rotating at high speed, and its temperature rises due to frictional heat.

When the thermometer 6 does not reach the preset temperature, the raw material is heated by a heat source such as electric heat or superheated steam installed in the external heating chamber 9 of the mixer via the steam pipe 15 to warm the raw material.

At this time, the pressure increases. Alternatively, if the temperature and moisture are insufficient to the predetermined values, water is supplied by pressure from the water supply pipe, and when the predetermined temperature is reached, the accelerator/deceleration is decelerated by the signal, and at the same time, the binder tank 12 is The binder is injected into the mixer 5 via the pressure pump 11 and the pipe 10, mixed with the raw materials (fine coke 1 and fine iron powder 1'), and melted and spread at a high temperature. During this time, the moisture in the raw material turns into steam, and since the mixer is sealed, the internal pressure increases. The pressure is measured by the pressure gauge 7, and if the pressure exceeds a predetermined value, it is discharged to the outside through the exhaust pipe 13 and the pressure regulating valve 14.

When the mixing process by the specified KB mixer is finished, the discharge port 1
8 is opened and stored in a hopper 19 on the molding machine, and then transferred to a roll-type molding machine 20 or a desk-type molding machine 2 as a molding machine.
1. As shown in FIG. 2, this roll-type molding machine 20 has drain grooves 26 that can easily remove excess water released during compression, and the desk-type molding machine 21 has drain grooves 26 around the mold circumference as shown in FIG. A dewatering groove 27 is provided. Both have good compression effects.

The compression-molded briquettes are passed through a hot air drying oven 26 to adjust the moisture and hardness of the finished product, depending on the properties of the binder used at that time. After passing through the hot air drying oven 23, the product is temporarily stored in a product hopper 24 or sent directly to a steelmaking converter or electric furnace as a recarburizing material for steelmaking.

According to this manufacturing method, the molding conditions can be adjusted in the same device in an extremely short time (4 to 6 minutes), and the recarburizer consisting of fine coke and fine iron powder is pulverized in the mixer 5. A series of steps of adding and mixing a binder and heating and dehydrating are processed in one step, and then molded in a compression molding machine 20, and if necessary, moisture is adjusted in a hot air drying oven 23.

In FIG. 1, the operation in the KBS mixer is a batch type operation, but the KB mixer 5 can be operated from 2 to 2 depending on the molding capacity of the roll type molding machine 20 or desk type molding machine 21.
It is also possible to provide three units in parallel and alternately discharge the mixed raw materials through the mixer and store them in the hopper 19 for continuous molding.

In addition, this KBS heater 5 is equipped with an external heating chamber 9, so that moist raw materials with a moisture content of 10 to 15% can be indirectly heated using saturated steam at 101 (saturation temperature 170°C). It is possible to maintain an appropriate amount of moisture during mixing and stirring.

As a raw material for metallurgical recarburization material by the method of the present invention, the particle size is -1
It uses fine coke of 1.0 mm and fine iron powder, and the fine coke includes various types of dust-collecting coke generated in the coke manufacturing process in steel works, such as coke extinguishing equipment (cn
Various types of fine coke such as the dust mentioned in Q) can be used, and the method of the present invention is particularly effective when using coke dust collected by a wet dust collection equipment such as a wet scrubber or a venturi scrubber.

Next, fine iron powder containing metallic Fe, such as converter OG dust, is preferable for effective use as an iron source, and one or a mixture of these two types may also be used. Containing metallic iron in fine iron powder is preferable from the point of view of effective utilization of the iron source, but if there is too much oxygen in fine iron powder, it will cause bumping phenomenon in electric furnaces for steelmaking, so adding iron oxide will be extremely difficult. Since only a small amount can be added, the metallic Fs should be at least 50% by weight, preferably 6.
It is desirable that the content be 0 to 70% by weight.

The blending ratio of fine coke and fine iron powder is such that the fine coke must be at least 10% in order to utilize metallic Fe as an iron source and to ensure the carbon content and specific gravity as a recarburizing agent. If the ratio is lowered, the specific gravity of the molded recarburizer will decrease, and if a recarburizer is used, it will float on the steelmaking bath, so a minimum of 40% is required, so the blending range is 10~
60:90-40 preferably 20-30:80-70.

As a binder for molding these raw materials,
Carboxy methylcellulose (CMC), polyvinyl alcohol-poval), propane de-asphalt (PDA), thermoplastic resin, thermosetting synthetic resin,
Starch, lignin, inorganic pentonite, cement, water glass, pitch, tar, wood tar, etc. are used, and when one or two selected from these are used, it is possible to ensure the crushing strength of the carburizer. It is valid. Among these binders, poval is preferred from the viewpoint of viscosity, but since it is an aqueous solution, it is not effective to use a mixer equipped with an indirect heating device and a high-speed stirring blade in the method of the present invention, such as a KB mixer. , it is possible to release excess water through the exhaust pipe 13 of the mixer and dehydrate it.

Furthermore, as for the amount of the binder added, as mentioned above, various binders such as inorganic acphalt-based, pitch-based, cornstarch, etc. can be used, but asphalt-based or pitch-based binders are preferably 1 to 10 g, preferably 5 to 8 g, and organic binders, such as poval, are used in amounts of 1 to 10 g. For those used as an aqueous solution, it is desirable to add 20 g or less in terms of crushing strength and carbon adjustment as a recarburizing agent. The crushing strength is usually 80 when used for electric furnaces.
~90v is enough, but the metallurgical recarburizer according to the present invention is
According to the method of the present invention, a material having sufficient strength of 1001e/piece or more can be obtained.

Although the softening point of coal tar separates at room temperature, it has a high binder effect in the KB mixer 5 due to heating and frictional heat.

Moreover, the molding shape can be made into any shape such as briquettes or pellets using the roll molding machine 20 or the desk molding machine 21.

Next, the present invention will be explained based on embodiment examples.

〔Example〕

Steelworks converter OG dust (particle size is 1W or less 0.05
~0.3 garden, 70-80% M-Fe70%) and coke extinguishing equipment (CDQ) collection dust) (V, M,: 0.5
%, particle size 0.01-0.2mm, 70-80%) KB
Mix with a mixer. A specific amount of the binder shown in Table 1 was added to each of these and mixed, and a double 0-kFJ, molding machine (molding)': 53 x 53, x: 14 ~
Molded with a 47cc machine mold R15), the resulting added μ
The physical properties of the S material were measured.

The above blending conditions and physical properties are shown in Table 1 below.

The obtained recarburized material for metallurgy has high crushing strength and apparent specific gravity,
Moreover, the M-F in the product was high, and the moisture content of the product was low even when an aqueous binder was used, so that it could be satisfactorily used as a recarburizing material in an electric furnace or the like.

〔Effect of the invention〕

The formed recarburizer for metallurgy according to the method of the present invention has the following advantages: 1) The density of the formed recarburizer can be controlled to 1 to 6 by controlling the addition of fine iron powder to coke powder at an arbitrary ratio, and the density of the formed recarburizer can be controlled to 1 to 6. Carbon can be efficiently added to the inside of the bath.

2) Since the carbon material is originally coke fine powder and has a large surface area, it has high carburization reactivity in a steel bath.

3) Since the size and shape of the molded solid can be controlled arbitrarily, it can be made into the optimal size and shape depending on the depth and width conditions of the steel bath.

4) Since the fine carbon material and fine iron powder are closely and uniformly distributed, some of the iron oxide is reduced and becomes an effective iron source.

5) Compared to using scraps in cloth as an iron source, Cu
#Sn*Cr*Zn and other impurities (tramp elements) are absent, making it a high-quality iron source. .

6) When applied to metallurgical furnaces such as electric furnaces, sufficient strength of the charge can be obtained.

It has great effects as a recarburizing material in metallurgical furnaces.

[Brief explanation of drawings]

FIG. 1 is a process diagram of the method of the present invention, FIG. 2 is a schematic diagram showing a dewatering groove of a roll-type molding machine, and FIG. 3 is a schematic diagram of a mold showing a dewatering groove of a desk-type molding machine. In the figure, 1: fine coke, 1': fine iron powder, 5:
High-speed rotating mixer, 7: Pressure gauge, 8, 22: Rotating vane,
9: External heating chamber, 12: Binder tank, 13: Exhaust pipe, 14: Pressure regulating valve, 18: Discharge port, 20: Roll molding! , 21: desk-type molding machine, 26: hot air drying oven. Agent Patent Attorney Tadashi Sato Year 2 Figure 3 Korororo 27-◇◇◇

Claims (14)

[Claims] (1) Using a mixture of fine coke and fine iron powder as raw material,
In the process of adding a binder to the raw material to produce a recarburized material, a series of steps of pulverizing the raw material, adding a binder, mixing, and heating and dehydrating are performed in one step using a mixer with high-speed stirring blades, and then A method for producing a recarburized material for metallurgy, characterized by compression molding and moisture adjustment. (2) The method for producing a metallurgical recarburizer according to claim 1, wherein the particle size of the raw material is 1 mm or less. (3) The method for producing a metallurgical recarburizer according to claim 1, characterized in that the blending ratio of the raw materials, fine coke and fine iron powder, is in the range of 10 to 60:90 to 40. . (4) The method for producing a metallurgical recarburizer according to claim 1, wherein the fine iron powder contains 50% by weight or more of metallic Fe. (5) The method for producing a recarburizer for metallurgy according to claim 1, wherein the fine iron powder is converter OG dust. (6) The fine coke is used in coke extinguishing equipment (CDQ)
The method for producing a metallurgical recarburizer according to claim 1, wherein the method is dust. (7) The binder is carboxy methyl cellulose (CMC), polyvinyl alcohol, propane de asphalt (PDA) thermoplastic acrylic resin,
Claim 1, characterized in that the material is one or two selected from thermosetting synthetic resins, starch, lignin, inorganic pentonite, cement, water glass, pitch, tar, and wood tar. A method for producing a recarburized material for metallurgy. (8) The method for producing a recarburizer for metallurgy according to claim 1, characterized in that 1 to 10% of the PDA is added and mixed. (9) The method for producing a metallurgical recarburizer according to claim 1, characterized in that 20% or less of the polyvinyl alcohol is added and mixed. (10) The method for producing a metallurgical recarburizer according to claim 1, characterized in that a rust preventive material is added during the mixing. (11) The method for producing a carburizer for metallurgy according to claim 10, wherein the rust preventive material is one selected from polyphosphoric acid, tannic acid, and boric acid. (12) In the mixer having high-speed stirring blades, heat is supplied via a heat supply device to indirectly heat the mixer, and the water content of the raw material is discharged to the outside of the mixer.
A method for producing a recarburized material for metallurgy as described in . (13) In the pulverizing process, water is added to the mixer to adjust the moisture content.
A method for producing a recarburized material for metallurgy as described in . (14) In the compression molding process, a roll type molding machine provided with a draining groove or a desk type molding machine provided with a dewatering groove on the circumference of the mold is used. Method for producing recarburized materials.