WO1996008328A1

WO1996008328A1 - Temperature increasing agent and temperature increasing method

Info

Publication number: WO1996008328A1
Application number: PCT/JP1994/001507
Authority: WO
Inventors: Masaru Takashima; Masayoshi Sakashita; Shido Ichinose; Yoshihiro Yamaguchi
Original assignee: Aikoh Co., Ltd.
Priority date: 1994-09-12
Filing date: 1994-09-12
Publication date: 1996-03-21
Also published as: KR960705645A; AU7624594A

Abstract

When slag solidified on a container, in a molten metal, and on the surface of a molten metal, residuals in the container and deposit therein are preheated, heated and melted during the refining and casting of a metal, fine powder of a thermosoftening waste plastic alone or fine powder of a mixture of such a plastic and a thermosetting waste plastic is used as a combustion and heating promoting agent. This enables the heating effect to be improved, and the natural gas expenses to be reduced greatly.

Description

Description Heating agent and heating method

Technical field

The present invention relates to the refining of metals, the preheating of containers such as electric furnaces and reverberatory furnaces, the rapid heating of molten metal, and the heating and melting of residual metal and slag solidified in furnaces and containers. The present invention relates to a technique using tic as a heating material.

Background art

Conventionally, before pouring the molten metal into converters, electric furnaces, ladle, tundish, and other holding furnaces used for iron and steel refining to avoid the temperature drop of the molten metal due to rapid cooling, and Alternatively, for the purpose of removing adhering water and crystal water from the refractory, sufficiently heat the above-mentioned melting vessel or melting furnace or refining furnace to raise the temperature, or hold a hand-held furnace or ladle after pouring, etc. The metal slag generated on the surface of the molten metal and solidified by cooling is heated, or the temperature is increased by deposits such as residual metal and gold slag in the molten metal container immediately after pouring in the production process. It is necessary to dissolve and remove, and as a means, LP gas, liquefied natural gas, city gas, coke oven gas, etc. are heated and heated with a gas burner as a heat source.

Also, when it is necessary to raise the temperature of the molten metal, specifically, for example, when it is necessary to raise the temperature of the molten steel during the operation of the converter during steel refining and the RH degassing treatment of the ladle, Small aluminum ingots or fluorosilicon are added to the molten iron and melted, and the temperature of the molten metal is raised by acid heat by blowing an appropriate amount of oxygen. Or in terms of the converter only, after pouring hot metal, oxygen is blown to raise the temperature to the target temperature. These heating materials and methods are merely concerned with the point of view of raising the temperature of the object as easily as possible.

Therefore, in the case of a conventional heating material and a heating method, for example, when heating and raising the temperature of a molten metal vessel, a converter, a ladle, and a tundish having a large heat capacity are in a relatively low temperature range of 950 to 1,100. 1 temperature in a short time to the extent and rises goals, 2 5 0~1, 3 0 0 e C or more to increase the temperature, gas such as LP gas; increase, oxygen Washido Combustion with 50% 10 ± 10% oxygen-enriched air Up and increase the heating time ^! The method power ^{s is} adopted. For example, the heating pattern of a 50-ton tundish for continuous steelmaking shows that it takes more than three hours to raise the temperature to 1,300 degrees from room temperature. The amount of LP gas required is 15 O at NrrfZ up to the first temperature rise of 30 O -C X 30 minutes (time to reach 300 ° C) + 200 NrfZ X 210 minutes (30 The time required to reach 1,300 from CTC) = 775 Nnf (LP gas consumption). In order to shorten the heating time, oxygen-enriched air is blown for 30 minutes to increase the temperature, and the atmosphere ^ is raised at a stroke to shorten the heating time by 40 to 60 minutes. However, the cost required for raising the temperature becomes expensive, and further reduction in the time required for raising the temperature has been desired in terms of maintaining the operation of the tundish.

Also, when the molten metal container, for example, the steelmaking tundish that has been poured, is reused continuously during the manufacturing process, the steel remaining in the tundish and the steel slag intervene in the early stages of the continuous manufacturing process. The quality is degraded due to the increase of materials and the mixture of foreign components, and in some cases, the nozzle may be closed at the start of the filling.Therefore, the steel and the steel residue remaining in the tundish are removed with a gas parner immediately after the production. The tundish is melted and removed to clean the inside of the tundish.In the case of a large tundish, for example, in the case of a 45 ton tundish, for example, around 5 ton of solidified steel and around 1 ton of steel slag However, there still remain problems such as the fact that much time is required to remove the residual and the cost of heating and dissolving is too high.

In addition, when raising the temperature of molten metal, for example, when operating a converter in iron and steel refining and performing RH degassing of a ladle, small aluminum lumps and floc as a heating material are added. aluminum blob a 1 ₂ 0 ₃ becomes at oxygen吹鍊, remain as inclusions, and when the oxygen in the molten steel is small, and the residual becomes aluminum-rich, degrade the material. In addition, fluorosilicone is expensive as a heating material and has a drawback that it does not have the heating effect as expected due to its small calorific value, and coke lump is used as the heating material and hot metal is poured into the converter. However, the sulfur component in the coke remains in the steel and causes quality deterioration.Also, during the refining of arc furnace steelmaking, coal powder or coke powder is added for the purpose of increasing the temperature, which also serves as desulfurization treatment. Mixed with or without aluminum dross and enriched with oxygen or pure oxygen and blown into the melt to ~ $ t However, it is as though desulfurization and vulcanization are performed at the same time for taste, and it was left as an issue. The present invention has been made in view of such circumstances, and has as its object that the heating cost is lower than that of the conventional method, a high temperature can be obtained in a short time, and the quality of molten metal can be improved. ^s It is an object of the present invention to provide a heating material and a heating method which do not cause defects caused by the heating material.

Disclosure of the invention

The heating material and the heating method according to the present invention include: a waste plastic having a calorie of more than 6,000 calories Zg; in particular, a heat-softening plastic such as polyethylene, polyethylene terephthalate, polypropylene, and polystyrene; After heating or softening at least one type, or mixing it with 30% by weight or less of a thermosetting plastic and molding it into a desired shape with a maximum diameter of 200 mm, heat the material, and refine the metal. The present invention relates to a method of using as a temperature-raising accelerator for preheating, heating, and drying of a container, a molten metal, a solidified slag, etc., when the container is partially repaired.

In a more preferred embodiment, the heat-softening waste plastic having the heat of 6,000 calories ZgiiLb is heated and softened, and then crushed or granulated to a size of 3 mm or less alone or a particle size of 1.5. mm or less of thermosetting waste plastic crushed to 30% by weight or more, or at least one kind of strong oxidizing agent etc. The heating material is obtained by mixing an amount of less than 10% by weight and granulating or pulverized to a size of 3 mm or less, and a heating agent containing a knitting strong oxidizing agent. This is a heating method in which oxygen mixed with 0 to 60% is used as a carrier gas and sprayed through a lance to a heating object heated to at least 800 * 0 to rapidly raise the temperature. Furthermore, oxygen, which mixes the heating agent obtained as described above with a heating object heated to at least 800 * 0 at 0 to 60% of air as carrier gas, is passed through a lance. Blowing force> and / or heating without passing through a lance Heating method in which the material is thrown into the object and heated rapidly, or aluminum dross is added to the above granulated or pulverized material by 10 to 70% The combined temperature rise IJ is empty * 0 to 60% Oxygen mixed as a carrier gas is blown into the molten gold via a lance through a lance, and a temperature raising agent and a temperature raising method that rapidly raises the temperature and also serves as a desulfurization treatment. To provide. In recent years, as the quality of life has improved, large quantities of general consumer goods have been available, The discharge power of general waste and waste of waste is increasing year by year, and the problems related to the disposal of ^^ are becoming social problems, and measures have to be taken. Among these general and industrial wastes, some of the waste plastics are recycled and used, but most of them are actually disposed of by landfill or incineration. However, these raw plastic raw material sources are synthesized from petroleum or natural gas, and are finite as resources.Since they are simply discarded or incinerated, they are a waste of resources and how effective use is Or as a social issue.

Under such circumstances, the present inventors have obtained the knowledge of the present invention as a result of earnest studies as to whether the high calorific value of the waste plastic can be used for industrially effective IJ. The heat-softening waste plastic used in the present invention preferably has a heat of 6,000 calories Z gliLh. It is difficult to obtain the required high-temperature atmosphere in a short period of time at a temperature of 6,000 calories or less. In other words, as shown in Fig. 1, a heat-softening waste plastic equivalent to ① 6,200 calories Z g and 5 5,500 calories Z g was granulated to a diameter of 1.7 mm, respectively. As shown in the comparison of the preheating time of 25 ton tundish with different materials, the time to reach 1,300 from 800 * 0 was 6,200 calories / g, which was achieved in 15 minutes. , 000 calories Zg equivalent products need more than 6,000 calories, just like 10 minutes ± 22 minutes. The amount of the warming agent used per hour was 900 gZ min.

As a method of granulating or pulverizing the 600-calorie Lh thermal softening ¾g | plastic, for example, heat of 150 iiLh is applied to soften and granulate with a granulator or 3 It can be liquefied at a temperature of 0 or more and granulated to 3 mm or less by the atomizing method. In addition, as a method of pulverizing, the waste plastic can be obtained by low-temperature embrittlement and then pulverizing with a crusher. Here, the reason for limiting to granulation or pulverization with a particle size of 3 mm or less is that 3 mmliU: complete combustion is difficult and H¾ easily occurs.

Similarly, a thermoset plastic that is mixed with waste thermosetting plastic crushed to a particle size of 1.5 mm or less and granulated or crushed to a size of 3 mm or less can be obtained in the same manner. Here, the plasticization was limited to the grinding of waste plastics to 1.5 mm or less. Granulation or crushing force of 3 mm or less i Furthermore, if the thermosetting plastic has a large particle size, it takes more time to decompose and gasify than the thermosoftening plastic when burning, and it does not burn in a well-balanced manner with the thermosoftening plastic. The reason why the amount of the thermosetting plastic was limited to 30% or less with respect to the heat-softening waste plastic is that it is difficult to obtain the required high temperature at 30% R ± due to the long heating time. It is.

Also, by mixing a strong oxidizing agent in an amount of 1 to 10% to a granulated product or a pulverized product containing the heat-softening waste plastic and / or the thermosetting waste plastic, the flammability and the burning rate are increased. And a high temperature can be obtained in a shorter time. Here, as the strong oxidizing agent, peroxides such as benzoyl peroxide, sodium peroxide, calcium peroxide, barium peroxide, strontium peroxide, magnesium peroxide, or potassium chlorate, sodium chlorate, At least one of chlorates such as barium chlorate and ammonium chlorate, or perchlorates such as ammonium perchlorate, potassium perchlorate, sodium perchlorate and potassium perchlorate, etc. You can choose.

Furthermore, the reason why the amount of the strong oxidizing agent is set to 1 to 10% is that the effect is small when the amount is less than 1%, and when the amount exceeds 10%, explosive burning power s is generated, which involves dangers and safety devices. Even if it is installed and blended by 10% or more, the temperature of Lh cannot be expected to rise. Here, strong oxidizing agents such as benzoyl peroxide need to be stabilized by adding appropriate stabilizers, for example, paraffin, stearic acid, etc. to the strong oxidizing agents to prevent explosion due to impact. It is.

In addition, heat-softening of 6,000 calories Z gliLh 1¾¾ plastics, after caro-thermal softening, moldings of any shape with a maximum diameter of 200 mm and heat-softening plastics A pulverized product is blended in an amount of 30% by weight or less, and a molded product of any shape having a maximum diameter of 20 O mm after heat softening can be easily obtained by extrusion molding or calo pressing.

The heating agent molded to a maximum diameter of 200 mm or less can be used for drying and heating preheating after a ladle for steel and a converter or a partial repair of a tundish. For example, after repair work due to melting of the converter slag line, dry and preheat to 800 "C or more with LP gas Thereafter, the formed heating agent is injected into the repaired portion, and oxygen is blown on the heating agent, so that a high temperature can be obtained in a short time. The molded product having a maximum diameter of 20 Omm or less is because if it is 20 Omm or more, it does not burn efficiently and a high temperature cannot be obtained in a short time. The shape of the molded product can be any shape, such as a square shape, a prism shape, a spherical shape, an almond shape, a disk shape, a column shape, etc. In short, the maximum diameter may be 200 mm or less. Absent. Here, the object to be heated, which is preheated to at least 800 * 0, is because if the temperature of the object to be heated is 800 or less, it takes time to decompose the heating material and exothermic reaction, and it is difficult to heat up quickly is there.

The reason for limiting the oxygen content to 0-60% is that if the air content exceeds 60%, it is difficult to shorten the heating time, which may cause incomplete burning.

Further, by adding 10 to 70% of aluminum dross to the temperature raising agent of the present invention, a temperature raising force which also serves as desulfurization of molten steel is possible. Generally aluminum dross is composed mainly from A 1 ₂ 0 ₃ that is an oxide and Kimu厲A Rumi, dissolved aluminum, is generated as Bok Bbudorosu generated during Sei錁. The aluminum mud scan the molten steel by吹鍊in the molten steel slag to absorb sulfur in the molten steel becomes slag close to or the composition comprising calcium one Arumine Bok _{_{(12CaO · 7A 1 2 0 3}} ) Te, be desulfurized are well known, and metal aluminum in the aluminum dross reacts with oxygen in the molten steel a 1 ₂ 0 _3, and the Me molten steel was raised Atsushise is for slagging.

The amount of aluminum dross added to the heating agent of the present invention is preferably 10 to 70%. The 10% or less not to close only in 12Cao '7Al ₂ 0 ₃ composition Atsushi Nobori of the molten metal, that is, the desulfurization slag Objectives of heating which also serves as a desulfurization can not be achieved, and more than 70% The power ^s heating function decreases. Also included in the present invention is a method of raising the temperature of the molten steel, which is not mixed with aluminum dross in advance, but is simultaneously blown into the molten steel. The waste plastic used in the present invention is specifically a heat-softening waste plastic having a heat of 6,000 cal / gi ^ Ut, such as polyethylene, polystyrene, polyethylene terephthalate, etc., and a calorie of 6,000 calories or more. Other heat-softening plastics can be used as long as they have the following. The thermosetting waste plastic is, for example, a fuanol resin, a melamine resin, or a polyurethane resin. You.

However, both waste plastics and thermosetting 1iJ plastics containing halogen elements such as chlorine and fluorine are not preferred because they generate gas when burned.

The heating agent and the heating method of the present invention have been described in detail above. However, the heating agent and the heating method of the present invention should be appropriately selected depending on the object to be heated and the purpose of the heating.

For example, a coke oven gas is burned with oxygen-enriched air to remove solidified steel and its slag remaining in the steelmaking dundish after use for 10 hours per hour. When heated with a warming agent containing 5% of sodium peroxide mixed with the polyethylene waste plastic of the invention, a fire of 2,200 m: 1 is generated and can be easily removed within 15 minutes. In other words, in the conventional removal method, the dundish which has been in a high temperature state is cooled after 1 hour or more, and high temperature preheating is required again when reused. According to the present invention, since it can be removed in a short time, it is slightly cooled, but it can be used as it is without preheating at the time of reuse. BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 shows the temperature rise curve when a heat-softening waste plastic of 6,200 calories / g and 5,000 calories Zg was put into a dandish and burned by blowing oxygen from a lance. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to Examples in order to more specifically and specifically describe the present invention.

[Example 1]

The pre-heating of a 60-ton capacity dundish for continuous steelmaking was carried out before longevity. Heat the L-gas as a heat source for about 90 minutes to raise the temperature of the dundish wall to 910 ° C.After that, stop heating with LP gas and reduce the particle size of waste polyethylene plastic to 1. After granulating to 7 mm for 15 minutes, oxygen mixed with 35% air is used as a carrier gas, and sprayed through a lance to heat the calo, and after the wall temperature of the dundish reaches 1,390 , Did the integration work. The results were as follows. The consumed waste plastic granulated product was 3 O kg, and the consumption of oxygen mixed with 35% of air was 540 Nm ³ . Further, in the heating agent and the heating method of the present invention, the order concentration of the pieces at the beginning of llfii, that is, 5 minutes after the start, was remarkably reduced as compared with the conventional method. Hereinafter, a comparison between the present invention and the conventional method will be shown.

Preheating time 105 minutes 150 minutes

LP gas extinction 275Nm ^! 475Nm ^: Waste plastic 30k

Granulated product consumption

139 ΟΌ 1200 * C 5 PPM from start to 5 minutes 12 PPM

锈 piece of water purple

(Example 2)

A 70-ton steelmaking ladle was preheated and heated. Liquefied natural gas was used as a heat source, and after the bottom surface temperature of the ladle reached 950, 85 Sfi% of polyethylene-based waste plastic and 15 Efi9 of phenol-based waste plastic were granulated to a particle diameter of 1.7 mm. The preheating of the ladle was performed by using a lance as a carrier gas containing oxygen containing the air-warming agent 38% in air as a carrier gas. The comparison between the present invention and the conventional method is shown below.

Preheating time 230 minutes 300 minutes LP gas extinguishing 100Nm ^! 725Nm ³

1200 to 120 o

Waste plastic 420kg

Granulated goods consumption 5

[Example 3]

The steel and steel slag remaining in the dandy after continuous sintering are removed using the heating agent of the present invention. A dissolution removal operation was performed.

Waste plastic made of polypropylene-based waste plastic with a particle diameter of 1.8 mm is mixed with a heating agent containing 5% by weight of sodium peroxide in a 55% air volume. Then, steel and steel slag remaining in the dundish were removed. Hereinafter, a comparison between the present invention and the conventional method will be shown.

The present invention

Dundish capacity 45 ton 45 ton

Amount of remaining steel 4.8 ton 4.9 ton

Amount of remaining steel slag 0.6 ton 0.7 ton

Coke oven gas consumption 4 ONm ³

Heating agent consumption of the present invention 30 kg

Heated dissolution removal time 12 minutes 65 minutes

[Example 4]

In the operation of the bottom-blowing converter, the waste plastic granulated product of the present invention consisting of 70% by weight of polyethylene and 30% by weight of polypropylene; a particle diameter of 1.7 mm was blown from the bottom tuyere of the converter using pure oxygen as a carrier gas. Temperature. The following shows a comparison with the conventional tuyere injection of coke powder (particle size of 5 mm or less) at the bottom tuyere.

The present invention m

Converter operation mode Bottom blowing ^ ^ Steel bottom blowing Steelmaking Converter molten steel tonnage 270 tons 270 tons Heating agent Polyethypro pro-coke powder

Waste plastic granulated product Heating agent injection amount 270k 270 k Iron scrap amount Z dissolution ratio 1 1% 1 1% Hot metal temperature before injection of heating agent 1325 "C 1328'C After oxygen injection and heating agent injection 1654 * C 1655 * C

Steel tapping temperature Sulfur of hot metal before injection of heating agent 0.023 0.023

Content% Sulfur after injection of heating agent and before desulfurization 0.023 0.025

Content%

[Example 5]

In the operation of the arc furnace for 80-ton steelmaking, the temperature was raised in combination with the conventional method and the desulfurization according to the present invention. The heating agent of the present invention is 40% by weight of aluminum dross, which contains 95% by weight of waste polyethylene plastic and 5% by weight of melamine waste plastic, 60% by weight of granules having a particle diameter of 2 mm, and 30% of metal aluminum content. The mixture is then injected into molten steel together with oxygen through a lance. In the conventional method, a mixture of 60% coke powder with a particle size of 5 mm or less and 40% aluminum dross containing 30% metallic aluminum is mixed. Similarly, the molten steel was subjected to infusion as a heating agent, and the heating was compared. Molten steel tonnage 80 tons 80 tons Heating agent Waste bra + aluminum dross-Cus powder + aluminum dross

Heating agent consumption 135 k 135 kg Molten steel temperature 1510 before heating agent injection. C 1510 * C After oxygen blowing and heating agent injection l 67 or 1 660 ° C

Temperature of molten steel of sulfur in molten steel before injection of heating agent 0.025 0.024

Yellow% Sulfur in molten steel after injection of heating agent 0.014 0.019

Yellow%

[Example 6]

Partially repaired a steelmaking ladle with a capacity of 270 tons. The slag line of the ladle above was partially damaged after use, and repair was performed by spraying an irregular refractory with an area of about 3.5 m ^{2 on} the damaged part. The preheat drying was performed by using a coke oven gas up to around 90 CTC, and thereafter, a molded product having a shape of 15 Omm X 5 Omm consisting of 90% by weight of a waste polyethylene plastic and 10 Mfi% of a phenol waste plastic of the present invention. 11 pieces were placed in the collection area, and oxygen was blown to dehydrate water and raise the temperature of the repaired part. The following is a comparison between the present invention and the conventional method.

The present invention

Heating agent Polyethylene 90+ Hue coke powder furnace gas

Knoll 10

Shape 1 5 Omm 5 Omm Area of repair area j. 5 m '3.5 m ² Maximum of 1800 repair area after heating. C 115 or

High temperature reached

Maximum reached from 90 O'C 1 1 minute 28 minutes

Time to temperature Industrial applicability

As described above, waste plastics, which are often discarded and landfilled, can be used for refining, manufacturing, preheating of containers and molten metal, and extremely high temperature for dissolving slag, container residues and attachments. It can be used as a facilitator. In addition, it can greatly contribute to saving natural gas and natural fuels that have been used.

Claims

The scope of the claims

1. 6,000 calories Thermoplastic waste plastic having a calorie of Zg or more alone or thermosetting waste plastic mixed at a ratio of 30% or less by weight of the thermosoftening plastic to a maximum diameter of 20 Omm A method of forming a metal into an arbitrary shape and using it for preheating, raising the temperature, drying, etc. the container during metal refining and manufacturing of molten metal and solidified slag.

2. Heat-softening waste plastic having a calorie of 6,000 calories or more is granulated or pulverized to a particle size of 3 mm or less after heating and softening, or is crushed to 1.5 mm or less. Heat-hardening 厲 ^ Blastic mixed within 30% for metallurgical refining, containers for production, molten metal, solidified slag, residue in containers, preheating of deposits, heating, melting Heating agent.

3. From 1 to the total weight: The warming agent according to claim 2, containing a strong oxidizing agent of I 0%.

4. The heating agent according to claim 2, wherein aluminum dross is blended in a total weight of 10 to 70%.

5. Spraying the heating agent of claims 2, 3 or 4 as oxygen carrier with oxygen containing 0 to 60% air through a lance or tuyere to at least 800 pre-heated gold and steel objects A heating method.

6. 6000 calories Thermoplastic soft plastic waste with calorie of more than Z g alone or 30% by weight or less of thermosetting waste plastic mixed to form any shape with a maximum diameter of 20 Omm the NoboriAtsushizai, 80 O ^e ladle C above preheated was for steel, was charged to a portion repaired portion of the converter or tundish, characterized by blowing oxygen containing from 0 to 60% air portion How to dry or preheat the repaired ladle, converter or tundish.

Three