JPH06271352A - Fireproofing material compounded with steelmaking slag aggregate - Google Patents

Abstract

PURPOSE:To provide a fireproofing material obtained by compounding the slag generated at the steelmaking stage of the high alloy steel including a stainless steel as an aggregate. CONSTITUTION:The basic fireproofing material is composed by compounding the slag generated at the steelmaking stage of the high alloy steel including a stainless steel as the aggregate, and incorporated with each main component of Cr2O3, FeO, MnO, CaO, SiO2 and the compd. having various crystal type formed in the two component system or three component system among these components, further, incorporated sometimes with a small amount of each component formed by adding in the steelmaking stage and/or a small amount of each component contaminated inevitablly in the steelmaking stage, and the steelmaking slag aggregate consisting of 5-100wt.% slag aggregate having the composition in which the oxide of chromium consisting essentially of the Cr2O3 component occupies 35-60wt.% of total slag and the remainder of basic fireproofing starting material aggregate is compounded to make the fireproofing material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an electric smelting furnace for smelting chromium-containing hot metal, an electric furnace for producing high alloy steel including stainless steel, an upper-bottom blowing converter, and a molten metal located between these furnaces. In a molten metal container (furnace) such as a ladle that is transported and / or refined and transported, the side wall and bottom of the container (furnace)
It is related to the basic refractory material used as a material to be sprayed or thrown into the (furnace bottom) (sometimes also referred to as a drop material or a baking adhering material). Therefore, the present invention relates to a refractory material formed by mixing slag generated in a steelmaking process of a high alloy steel including the stainless steel as an aggregate.

[0002]

2. Description of the Related Art In recent years, an electric smelting furnace for smelting chromium ore to smelt chromium-containing hot metal, mainly producing high-alloy steels including stainless steel, and producing valuable metal components including chromium components, etc. An electric smelting furnace for smelting chromium-containing hot metal by electric smelting using the by-product contained as a raw material, an electric furnace for making high alloy steel including stainless steel, an upper bottom blowing converter, and smelting between these furnaces In a molten metal container (furnace) such as a ladle that simply transports various steelmaking melts or is used for both refining and transport, inside these containers (inside the furnace)
As a refractory that constitutes the side wall and bottom of the furnace (furnace bottom), a large amount of irregular refractory (hereinafter simply referred to as refractory material, used for refractory bricks for new construction and repair of such side wall and bottom) Depending on the application, it may be called a basic refractory material) is used. This amorphous refractory, that is, the refractory material, is relatively expensive and is mainly used for repair in large quantities.
Concretely, the material for hot spraying to the lining portion of the side wall, the protection of the refractory bricks arranged at the bottom of the vessel, and the material for throwing into the worn part (drop material, baking adhesion during hot repair) Used as a material).

In addition, recently, various molten metals produced or melted as described above (including the above-mentioned molten metal, hot metal and molten steel)
In order to mass-produce, with good quality, high efficiency and high productivity economically (at low cost), a large amount of raw materials and molten metal are charged and stored in a large capacity container. For various raw materials and molten metal in the container, various gases are blown from the top blowing lance and bottom blowing tuyere that are properly installed in the container to forcibly stir the molten metal and promote melting and melting of the various raw materials. Or promote various reactions to improve the refining effect. However, as the above-mentioned melting, melting and refining proceed while performing gas blowing in this way, refractory and the like forming the inner surface of the container, especially the bottom blowing tuyere arranged at the bottom of the vessel and its surroundings are arranged. The refractory bricks, etc. that are present are worn more severely by the forced stirring action of the molten metal and slag. Also, the part of the side wall refractory (slag line) inside the container, which almost corresponds to the position of the uppermost part of the slag that is in a layered state and floats on top of the molten metal stored in the container, is worn more severely. It is. Therefore,
Expensive new bottom blown tuyere, a molten metal container newly constructed using refractory materials such as refractory bricks and refractory materials are used repeatedly while being repeatedly used, and its life is extended as much as possible. In order to do so, it is necessary to interrupt the operation several times along the way, replace the bottom blown tuyere and refractory, protect them and repair various damaged parts more thickly and more frequently than before. Is no longer true.
Therefore, the refractory material as a refractory material forming the inner surface of the container is also used in large quantities under more severe conditions than ever before.

Refractory materials used in this way have hitherto been used.
For example, a basic refractory raw material such as expensive seawater magnesia is generally used as an aggregate, and an appropriate amount of a binder is added to and mixed with the aggregate. Furthermore, a steel-making furnace slag generated from an electric furnace, a converter, a ladle, etc. is mixed as a partial substitute for the basic refractory raw material that has been conventionally used as an aggregate. (Sometimes referred to as a refractory composition) are introduced in the following publications. (1) Dilime silicate (2C
It consists of a mixture of 40 parts or less of basic slag whose main component is aO.SiO ₂ ) and 60 parts or more of magnesia clinker, and the mixture is bound with a binder that does not substantially contain water to prevent the digestion phenomenon. Basic fireproofing agent (JP-A-51-1
No. 23208). (2) A refractory composition containing a steelmaking furnace slag containing 1% or less of free CaO and 1.5 to 3.0% of a phosphorus component as P ₂ O ₅ (JP-A-54-156020). (3) It discloses that a part or most of the converter slag can be a basic refractory material.
5 parts by weight of one or two or more pitches and / or synthetic resins having a residual carbon content of 30 to 70% in 100 parts by weight.
A basic hot spray repair material which is coated or added in the form of granules in an amount of 50 parts by weight (JP-A-55-846).
4 publication). (4) Magnesia-based refractory material 10 to 88% by weight and free C
Steelmaking furnace slag 10 to 88 wt% in which aO is 1% or less and 2CaO · SiO ₂ exists in a high temperature type or a medium temperature type crystal type at normal temperature, a carbon material 1 to 20 wt%, and a powder digestion inhibitor 1 Steelmaking furnace slag-containing refractory composition consisting of ˜7% by weight with the aim of preventing collapse phenomenon (JP-A-57-3
No. 4083).

The refractory materials described in detail in the above publications are common in that steelmaking furnace slag is used.
All of them are aimed at preventing the collapse phenomenon of the refractory material when it is actually used as a refractory material forming each part of the inner surface of the container, and the digestion phenomenon by the moisture of the refractory material and the formation of various crystalline compounds at relatively high temperatures. Disclosed is a technical idea to solve the drawback of pulverization phenomenon caused by the transformation, transformation, etc. by using at least some non-aqueous binder together.

[0006]

As described above, in each of the publications (1) to (4) described above, the steelmaking furnace slag is used and the refractory material using the slag is used. However, since various problems that are common or common to the use of such a refractory material are described in detail, these problems will not be described in the present invention. However, various problems that are not clarified in each of these publications will be described below. B) Steelmaking furnace slag, which is produced in large quantities in one bite, is very different, at least in terms of its chemical composition and physical properties, as will be explained later, and steelmaking that cannot be actually used. There are many furnace slags. B) It is difficult to mix and prepare various steelmaking furnace slags to meet such characteristics, and the refractory material made by using the adjusted steelmaking furnace slag requires labor, investment amount, manufacturing cost and so on. Even if you consider it, it is not economically efficient. C) Such a steelmaking furnace slag, that is, a refractory material formed by using the steelmaking furnace slag described in each of the above-mentioned publications, cannot be used anywhere and has no versatility. On the contrary, the required characteristics of the refractory material are also greatly restricted by the purpose of use, the purpose of use, the place of use, the range, and the range of application. D) For example, the slag generated from the steelmaking process of the high alloy steel containing stainless steel, which is not specifically described in the above-mentioned publications, is as follows, and is caused by various reasons as described below. Although it is difficult to handle, and it is a large amount of industrial waste that is generated from the steelmaking process, it is disposed of in landfills and is rarely used, but its countermeasures are taken up as a serious problem. However, the proper usage is not found and it is not established.

This slag does not substantially contain a chemically stable nickel component that is not oxidized, but Cr ₂ O ₃
It contains a fairly large amount of heavy metal oxides, whose main constituents are.・ Cr ₂ O ₃ , FeO, MnO, MgO, Ca
Since it contains a large amount of each of the main components such as O and SiO ₂ , various crystal type compounds formed in the two-component system and the three-component system among these components are many. In many cases, a specific metal component or the like other than these is added, and if so, other various compounds are further produced and contained. -In some cases, fluorspar (containing CaF ₂ ) is added to lower the melting point of the slag and the softened slag is sufficiently stirred and brought into contact with the molten metal to improve the refining effect without waste. It is difficult to use slag with a low melting point as a refractory material. It is difficult to handle because it contains calcium fluoride (CaF ₂ ) and has a low melting point, and also contains dicalcium silicate (2CaO · SiO ₂ ) which is extremely unstable in moisture (humidity).・ As heavy metal oxides and harmful substances 6
Since there is a risk of containing valent chromium substances and calcium fluoride, it is difficult to handle them, and the landfill use of these substances
Storage and sediment disposal are becoming increasingly difficult.・ Since a large amount is generated, a vast area is required for this landfill, storage, and accumulation.・ As a method of using this slag, it is possible to use it for roads by mixing it with sand, etc., or to use it as a cement admixture, or as a soil neutralization improver, but in terms of pollution prevention, From an economical point of view, proper and sufficient usage has not been established.

Therefore, the present invention utilizes the slag generated from the steel making process of the high alloy steel including the stainless steel described in the above item 2) while solving the above-mentioned various problems as much as possible. Concerning the industrial waste processing measures, it is effective not only in terms of energy saving and resource saving,
In order to reuse this slag as a product with no risk of secondary pollution without discarding it as much as possible, we focused on solving the problems of this slag and used it as an aggregate to form an irregular shape. It is an object to provide a refractory material, that is, a refractory material.

[0009]

SUMMARY OF THE INVENTION In view of the problems detailed above, the present inventors have conducted various experiments to investigate and investigate, and as a result, (a) As described above. Steelmaking furnace slag, especially refractory materials that use slag generated from the steelmaking process of high-alloy steel including stainless steel, are not versatile due to great restrictions due to their intended use and scope of application. Considering from the characteristics of chemical composition and properties, basically the slag generation department (generation process)
Or it is economical and economical to reuse it in related processes existing around it, or (b) Therefore, a refractory material formed by using slag generated from the steelmaking process of high alloy steel including stainless steel. Is mainly a molten metal container (furnace) of the same or similar steelmaking process as described in the beginning of the above [Prior Art] and each electric smelting process in the related process surrounding the steelmaking process. It is a good idea to use it mainly for molten metal containers (furnace) such as furnaces,
(C) To minimize the content of other basic refractory raw material aggregates as much as possible, and to use the slag as much as possible to obtain the desired refractory material, (d) as in the conventional steelmaking furnace slag, (E) As described in the above [Prior Art], a non-aqueous binder or the like is used to prevent pulverization associated with the collapse phenomenon of the refractory material. It has high corrosion resistance and low melting point substances as much as possible in order to make it economically durable with better productivity under severe usage conditions of various refractory materials that compose the inner surface of the molten metal container (furnace). It does not contain (a),
In order to have versatility considering the application range of (b), the melting point of the aggregate of this slag should be high so that the fire resistance of the slag is SK39 or higher, and (f) the inner surface of the molten metal container (furnace) is configured. By using a refractory material formed by using this slag as a refractory material, it does not adversely affect the important molten metal, that is, it does not deteriorate the quality by contaminating the molten metal or reducing its cleanliness, etc. He has determined that it is necessary and important.

That is, based on the above-mentioned contents of investigation, the refractory material containing the steelmaking slag aggregate for achieving the above-mentioned object of the present invention is used in the steelmaking process of high alloy steel including stainless steel. A basic refractory material formed by mixing generated slag as an aggregate, which comprises Cr ₂ O ₃ , Fe
It contains O, MnO, MgO, CaO, SiO ₂ main components and various crystal type compounds formed in the two-component system and the three-component system between these components, and
5 to 100% by weight of slag having a chemical composition in which chromium oxide mainly composed of ₂ O ₃ component occupies 35 to 60% by weight of the entire slag, and the rest of basic refractory raw material aggregate The present invention has been completed based on the knowledge that a refractory material made by blending with is obtained.

[0011]

The refractory material containing the steelmaking slag aggregate according to the present invention and its operation will be described in detail based on the results obtained by measuring, investigating and examining various experiments, and examples. First, a molten metal container such as an electric furnace, a converter, a ladle in a steelmaking process of a slag used as an aggregate of a refractory material containing a steelmaking slag aggregate according to the present invention, that is, a high alloy steel including stainless steel. The general chemical composition and properties of slag generated from (furnace) will be explained. This slag is generally subjected to basic operation in the entire steel making process, and the slag material added or added separately for each process, that is, for each container (furnace) is also basicly mixed, and each container (furnace) is used.
As a refractory having an inner lining, for example, CaO or Mg at least as a main component typified by dolomite bricks.
Since a basic CaO-containing refractory brick containing O is used to ensure the durability of the refractory in this basic operation, it is inevitably generated as a basic slag.

[0012] In this way, each process or each container (furnace)
The slag generated separately is different in the role (purpose, function) to be performed for each process or container (furnace), the difference in steel type of the molten metal produced in the steelmaking process, and therefore, the slag is added during the initial period or the process. Difference in the added metallic material and its composition,
Similarly, the difference in the slag material added or added and the composition thereof, conversely, the difference in the method of removing slag generated during or between the steps and the degree thereof, and the process or container (case) accompanying these differences ( Steelmaking (operation) including refining for each furnace
Due to differences in conditions, differences in various operating conditions throughout the steelmaking process, etc., various differences occur in their chemical composition and their properties. Actually, as described above, fluorite (Ca
The slag generated by adding (containing F ₂ ) and lowering the melting point of the slag is not only difficult to use in the refractory material according to the present invention, but also unusable slag may occur.

Further, the slag generated from the steelmaking process of the high alloy steel including the stainless steel is different from the chemical composition of the steelmaking furnace slag introduced in the above-mentioned publications by performing the high basicity operation. Therefore, it is characterized by being a basic slag mainly containing a stable Cr ₂ O ₃ (trivalent chromium) component and containing a considerably large amount of chromium oxide. This chromium oxide and FeO, MnO, MgO,
It contains CaO and SiO ₂ as main components, and further contains various crystal type compounds formed in the two-component system and the three-component system between these components. Compounds of various crystal types thus produced are described and introduced in the above-mentioned publications, and the SiO ₂ —Ca of FIG.
Compounds of various crystal types (CaO
・ SiO ₂ , 3CaO ・ 2SiO ₂ , 2CaO ・ Si
O ₂ , 3CaO · SiO ₂ , ...) and Ca in FIGS. 3 and 4
O-SiO ₂ -Cr ₂ O various crystal forms of the compounds shown in the equilibrium diagram in 3-component system _{3 (CaO · Cr 2 O 3} , 3
_{CaO · Cr 2 O 3 · 3SiO} 2, ...) , etc., Fe-C
r alloy coexistence condition, slag temperature condition, Fe in slag
The (FeO) content is varied while varying in kind and quantity depending on the basicity condition, the solubility of chromium oxide in slag, and the like.

Further, in this steelmaking process, for example, Mo, Cu, Al, Ti, Nb or the like is added as a special component for melting high alloy steel including stainless steel, and A
Since a strong deoxidizing agent such as l and Ti is added, a small amount of oxide produced by oxidation of these is also contained.
On the other hand, in association with the metal material, the melt temperature adjusting material, the slag material, the reducing material, the single or complex deoxidizing agent, the desulfurizing material, etc., which are added or added between the initial stage of the steelmaking process and the process, for example, CaF ₂ , P ₂ O ₅ , S content (sulfides), various oxides that adversely affect the quality of the molten metal that is inevitably mixed in such as small amounts of unavoidable contaminants such as low-melting substances described below. It also contains impurities such as.

Next, the operating conditions outlined in the steelmaking process in which a refractory material comprising the slag having the chemical composition as described above as an aggregate is actually used, and conversely, the refractory material should be required and equipped. The characteristics and conditions will be described. As mentioned in (e) above, an electric furnace that melts or melts various raw materials with an extremely high-temperature arc, and oxidation refining that normally raises the temperature to 1700 ° C or higher by O ₂ blowing Since it is a steelmaking process that includes a converter that also performs refining and a molten metal container (furnace) such as a ladle that carries and / or refines and carries such high-temperature molten metal, the refractory material that forms the inner surface of this container (furnace) The refractory material used as a material is used under severe conditions with a forced stirring action, so it has high temperature corrosion resistance and its fire resistance is SK39 or higher (1880 ℃
Above) [Refractory Notebook (1981 version), 1982 10
Issued on March 31, second edition, published by the Institute of Refractory Technology. Then, as described above, basic slag is generated from each container (furnace) in the steelmaking process as described above by the basic operation, and the slag basicity {(% CaO +% M
gO) / (% SiO ₂ )} [wt%] is in the range of 1.2 to 3.0, and the chromium oxide mainly composed of Cr ₂ O ₃ component accounts for approximately 1 to 60 wt% of the entire slag. We have obtained the survey results that the content is varied depending on the range.

Therefore, based on the results of such a rough survey on slag, a large number of basic slag generated from a converter in which molten metal was smelted without adding fluorspar was placed as follows. Processing operation, basic aggregate,
That is, since a basic refractory material was manufactured as a prototype, typical prototype examples are shown in Table 1 and described below. When the basic slag generated from this converter is prototyped as an irregular shaped refractory, that is, an aggregate of refractory material, the slag shape state at the time of generation is solidified into a large lump, so a breaker and a jaw crusher, etc. After crushing, 25 ~ 2 by rod mill etc.
The particle size was adjusted by crushing to a predetermined particle size of 0 mm or less according to the intended use. In addition, not only various oxides and sulfides but also valuable metal components such as Fe, Cr, and Ni may be mixed in this slag, so specific gravity or magnetic separation is carried out as necessary. . Through these pre-treatment processes, slag is digested by water (moisture) and pulverized (deteriorated).
It was carried out with care so as not to occur.

[0017]

[Table 1]

In Table 1, high alloys including stainless steel
Inside the slag generated from the converter in the steelmaking process
For two types with typical chemical composition, 5 mm or less
The below crushed particle size adjusted product is A-1, crushed particles of 3.36 mm or less
Degree-adjusted product is A-2, crushed particle size adjusted product of 20 mm or less is B
Then, the particle size composition (wt%), representative chemistry for each of these
Ingredient (% by weight), basicity {(% CaO +% MgO) / (%
SiO₂)}, Content of low melting point substances below 1000 ° C (weight
%), The fire resistance of the remainder excluding the low melting point material [SK (Zege
(Lukegel), see "Refractory Notebook" above], Autocle
Pulverization rate (weight of 3 atmospheres x 2 hours) (weight
%) [Gakushinho 7. Dolomite clinker digestibility test
Method, (II) by autoclave method]
Indicates a value. Of these measured values, low melting point substances below 1000 ° C
The quality content (% by weight) was measured by adding 0.2
A circle with a diameter of 50 mm and a thickness of 10 mm after crushing to 97 mm or less
Silicon made into a plate specimen again
Electrofused magnesia substrate in electric furnace 3 with heating element
Place the disk-shaped test body 1 on 2 and heat it by applying electricity.
When kept at 1000 ° C for 5 hours, this heating causes a disc shape test.
The low-melting substance elutes from the body 1 in the fused magnesia substrate 2
The difference in weight before and after heating at 1000 ℃
Therefore, the content of the low melting point substance was measured by the following formula. W₁: Weight before heating at 1000 ℃ (gr) W₂: Weight after heating at 1000 ° C (gr) Low-melting substances below 1000 ° C elute from each disc-shaped test body 1
For the remaining test piece after regrinding, a test piece for refractory
Made a piece of "Segel corn"
It was measured. On the other hand, it was penetrated into the fused magnesia substrate 2
As a result of identifying low melting point substances, glass that generally melts at low temperatures
K, such as substances that easily form a glassy or glassy material₂O, Na
₂O, Pb₂O_Five, B₂O₃, SnO, etc. were detected.

As the refractory material mixed with the steelmaking slag aggregate according to the present invention, if the slag is treated as described above and shown in each measured value of Table 1, each slag is used as an aggregate. Although there is no problem in using it, since it is a refractory material made by mixing other basic refractory raw materials such as seawater magnesia as the balance aggregate, the pulverization rate (wt%) of other basic refractory raw materials to be blended Was also measured and investigated in the same manner as described above. Table 2 shows the measurement results of the pulverization rate (% by weight) of seawater magnesia, natural magnesia, magnesia dolomite type (synthetic magdrome etc.) and calcined dolomite type (calcined dolomite etc.) which are usually used as the raw material. In this measurement study, the present inventors have found that if the digestion property is 2.0% by weight or less of the natural magnesia pulverization rate shown in Table 2, the pulverization (deterioration) occurs due to the digestion even during the crushing and mineral processing. I have no knowledge.

[0020]

[Table 2]

Based on the measurement and investigation results shown in Tables 1 and 2 and the findings explained above, not only the slag generated one after another from the above-mentioned converter that satisfies the following condition range but also from the steelmaking process Properly sample from each slag generated, prepare a test piece "Seegel cone" for refractory measurement from each test slag, and while heating each Zegel cone to a high temperature in the furnace The melting start temperature (° C) of Cr is given to the melting start temperature (° C) of each sample slag (aggregate).
The influence of the content (% by weight) of the oxide of chromium mainly composed of ₂ O ₃ component was investigated. Each test slag condition range ・ Basicity of slag: Range of 1.2 to 3.0 ・ Content of chromium oxide mainly composed of Cr ₂ O ₃ component contained in slag: 1 to 60 weight % Range: -The content of the low melting point substance of 1000 ° C or lower in the slag is less than 10% by weight based on the measurement results shown in Table 1.

From the results of the investigation shown in FIG. 5, as the content (% by weight) of chromium oxide mainly composed of Cr ₂ O ₃ component increases in the slag (aggregate) generated from the steelmaking process, The melting start temperature (° C) tends to be high, and when the content of this chromium oxide reaches 50 to 60% by weight, the melting start temperature (° C) tends to approach a localization state of about 1900 ° C. I got some knowledge. As described above, as a refractory material as a refractory material that constitutes the inner surface of a container (furnace) such as a converter used at a high temperature of 1700 ° C. or higher as mentioned in the item (e), at least this oxide of chromium is used. Content of 35% by weight or more,
It was found that a content of 40% by weight or more is desired in order to obtain a fire resistance of SK39 or higher (1880 ° C or higher).

However, not only the slag generated one after another from the converter but also most of the large amount of slag generated from the steelmaking process is the same as the measurement and investigation results shown in Tables 1 and 2 and FIG. According to the range of conditions and knowledge described above, for example, a powdering rate by digestion of 2% by weight or less and a chromium oxide content of at least 35% by weight or more can be used as a refractory material satisfying a high fire resistance condition. However, there is a residual part that cannot be used.
Therefore, in order to effectively use and reduce this unusable residue, and to enable it to be used as a refractory material satisfying higher corrosion resistance and refractory conditions with a powdering rate of 2% by weight or less, it is applicable. The idea is to use a refractory material that is made by adding an aggregate of basic refractory raw material such as seawater magnesia or natural magnesia that has been used as an aggregate to the aggregate made of slag, and actually use it. I decided to try it.

[0024] As a result of empirical results, Cr was experimentally examined while changing the compounding ratio of both aggregates in order to satisfy various conditions desired as a refractory material depending on the purpose of use and application.
Chromium oxide, which is mainly composed of ₂ O ₃ component, is contained in 3% of the entire slag.
According to the present invention, 5 to 100% by weight of a slag generated from a steelmaking process having a chemical composition occupying 5 to 65% by weight is used as an aggregate, and the balance of the basic refractory raw material aggregate. A refractory material containing the steelmaking slag aggregate was obtained. As described in the above (a) to (c), it is preferable that the refractory material containing the steelmaking slag aggregate according to the present invention is made of only the aggregate using the slag generated from the steelmaking process. It is necessary that the mixing ratio of the aggregate using this slag is at least 5% by weight or more.
If the amount is less than 5% by weight, it is not possible to sufficiently absorb the treatment cost required for the pretreatment process such as crushing particle size of this slag, identifying the chemical composition and checking whether or not it can be used. This is because the benefit of reducing and utilizing this slag as an aggregate mainly in the steelmaking process disappears.

However, as a result of using the refractory material containing the steelmaking slag aggregate according to the present invention for a long period of time, as described in the above item (f), the deterioration of the quality is particularly permitted in the steelmaking process. There is a case in which the essential molten metal that is not processed is contaminated with the P component and the S component, and unnecessary substances and man-hours are required to remove them, resulting in cost increase. As a countermeasure against this, it has been empirically found that the P ₂ O ₅ component in a small amount of each component inevitably mixed in the steelmaking process is preferably 0.5% by weight or less of the whole slag. Further, it has been found that the S pure content is also preferably at least 0.2% by weight or less of the whole slag.

Further, the refractory material in which the steelmaking slag aggregate according to the present invention, which is compounded as described in detail above, is mixed with the refractory material forming the inner surface of various molten metal containers (furnace) mainly in the steelmaking process. When using conventional steelmaking furnace slag when actually using it as a part of the product, unlike the problem solved by using a binder such as a non-aqueous system to prevent pulverization of the aggregate that uses this slag In order to satisfactorily bond aggregates mixed in a desired ratio with each other and to adhere well to refractory bricks as a refractory that constitutes the inner surface of the container (furnace), use this slag as aggregate. 5-100% by weight
And a basic refractory raw material aggregate and 100% by weight of both aggregates, and a total of 0 to 10% by weight of a binding binder and / or an adhesive binder is added and blended. It is preferable to use materials appropriately. As such a binder, sodium silicate or clay specifically has any function, but it is preferable to use the latter as a binding binder and the former as an adhesive binder.

[0027]

EXAMPLES The following will describe in detail the refractory material containing the steelmaking slag aggregate according to the present invention and the method of using the same by specific examples according to various applications (applied parts).
Table 3 shows examples and comparative examples of the refractory material containing the steel slag aggregate according to the present invention for each application (application part).
The details will be described below according to the use shown in Table 3. (A) Example as a hot-blasting refractory material for an electric furnace In an electric furnace in a steelmaking process of high alloy steel including stainless steel, the converter slag A-1 shown in Table 1 and described above is used.
A refractory material containing 20% by weight as an aggregate (Example 1) and a fireproof material containing 50% by weight (Example 2)
And were tested as a spray refractory material on the surface of the refractory bricks constituting the side wall of the electric furnace for one month. Spraying conditions: Discharge (injection) air pressure 2.0 kg / cm ² Average discharge rate 70 kg / min Both initial adhesion and workability during spraying are comparable to conventional blended spray refractory materials (comparative example). There was no 1
Table 3 also shows the trial results for a month and the economical efficiency of Examples 1 and 2. In Table 3, the criteria for economic evaluation of sprayed refractory materials are the basic unit used (kg / molten metal to
n) x sprayed refractory material product cost (ratio) = basic unit price used (ratio), and the unit consumption ratio (ratio) is used for the determination. In Example 1, the basic unit used is almost the same as that of the comparative example, and there is a merit of reducing the original unit price by about 7%. In Example 2, although the pick-up of the unit consumption to be used is recognized due to the deterioration of the corrosion resistance, since the product cost ratio is low, the unit price ratio to be used is lower than that of the comparative example.
That is, Examples 1 and 2 which are the products of the present invention show that the refractory material formed by mixing the converter slag as an aggregate reaches the purpose of use and has a recycling effect.

[0028]

[Table 3]

(B) Example as a hot-spray refractory material for ladle In a ladle for transporting or refining / transporting various molten metals between each container (furnace) in the steelmaking process, a side wall portion of the inner surface of the ladle or As a refractory material sprayed on the surface of the refractory bricks that constitutes the bottom of the furnace, a refractory material (Example 3) prepared by blending 30% by weight of the above-mentioned converter slag A-2 shown in Table 1 as an aggregate,
Life of several ladles 1 generation period (average useful life: 16
It was used twice). Spraying conditions: Discharge (injection) air pressure 1.7 kg / cm ² Average discharge rate 30 kg / min Both initial adhesion and workability during spraying are comparable to conventional blended spray refractory materials (comparative examples). It was good. Although the erosion condition in the slag line portion of the side wall is slightly larger than that in the comparative example,
Comparative examples of seizure ability and residual efficiency on the gas-bottomed tuyere at the bottom of the hearth, the wear parts of the hearth refractory bricks around it and the wear parts of the corners, and joint damages between refractory bricks throughout the furnace Slightly better than Example 3 can be effectively recycled and is more economical than the comparative example.

(C) Example as Hot Drop-Down Refractory Material for Electric Furnace Gas-bottomed tuyere and a furnace around it at the bottom of the electric furnace A refractory material containing 85% by weight of the above-mentioned converter slag B shown in Table 1 as an aggregate from the opening of the furnace top after the molten metal was smelted to a locally large wear portion of the floor refractory brick (Example 4). ) And a refractory material (Example 5) formed by blending 95% by weight thereof were dropped and repaired for about 1 month.
As a result of this trial, as compared with the conventional dolomite magnesia drop-in refractory material (comparative example), both seizure and durability were about the same use effect and economical.

(D) Example as a hot drop refractory material for an electric smelting furnace As a hot drop refractory material to a hearth wear (bed dug) spot in the bottom of the electric smelting furnace, A refractory material (Example 6) consisting of only the aggregate of the converter slag B shown in Table 1 above was dropped from the furnace top or the side wall opening of the furnace after the molten metal was poured out, and repaired for about one month for trial use. did. As a result of this trial, it could be used without any particular problem as compared with the conventional refractory material (comparative example), and both the seizure property and the durability have the same effect in use and are economical.

In each of the examples (A) to (D) detailed above, all of the examples shown in Table 1 above are shown as the aggregate of the refractory material containing the steelmaking slag aggregate according to the present invention. Converter slag A (A-1, A- in the steelmaking process described above
2) and only converter slag B is used. However, as the refractory material containing the steelmaking slag aggregate according to the present invention, as described above, in order to recycle as much as possible the slag generated from the steelmaking process, the chemical composition of the slag described in detail above and Any slag is acceptable as long as it satisfies the constraint conditions such as properties. As the slag having such a chemical composition constraint, the slag that can be rephrased as follows can be used for the aggregate. C
aO-, the SiO _2, Cr ₂ O ₃ component is a slag with each major component, surrounded by a-b-c-d in the equilibrium phase diagram of _{CaO-SiO 2 -Cr 2 O 3} 3 -component system shown in FIG. 4 In the figure, the CaO component value is 0 to 39 wt%, S
iO ₂ component value is 0 to 45% by weight, Cr ₂ O ₃ component value is 18
It is sufficient that the slag has a chemical composition within the range of ˜100% by weight. The liquidus temperature in the region of the chemical composition is approximately 1900 ° C or higher, and the desired fire resistance as described above: SK
It has properties exceeding 39 (1880 ° C). The chemical composition of the converter slag A (A-1, A-2) shown in Table 1 above is shown in FIG. 4 in the chemical composition region in the equilibrium diagram of the CaO—SiO ₂ —Cr ₂ O ₃ 3 component system. Corresponding to point A, the chemical composition of converter slag B also corresponds to point B.

[0033]

The refractory material in which the steelmaking slag aggregate according to the present invention having the above-described detailed structure is compounded is a subject of the present invention based on the various items described in the above items a) to d). Which is very effective industrially. Then, if the proportion of the basic refractory raw material aggregate such as conventional magnesia or seawater magnesia is reduced as much as possible according to the purpose of use and the purpose of use (application part), further economic efficiency is achieved. It can be recycled.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the structure of a test electric furnace provided with a heating element for measuring the content of a low melting point substance.

FIG. 2 is a phase diagram of a SiO ₂ —CaO system.

FIG. 3 is a local sectional view in a high temperature region of an equilibrium diagram of a CaO—SiO ₂ —Cr ₂ O ₃ three-component system.

FIG. 4 is an equilibrium state diagram of a CaO—SiO ₂ —Cr ₂ O ₃ three-component system.

FIG. 5 is a relationship diagram showing the influence of the content (% by weight) of chromium oxide mainly composed of Cr ₂ O ₃ component on the melting start temperature (° C.) (refractory level) of slag (aggregate). .

[Explanation of symbols]

 1 Specimen (specimen) 2 Grain base 3 Test electric furnace

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Yamamoto 4976 Nomuraminami-cho, Shinnanyo-shi, Yamaguchi Prefecture Inside the Shunan Steel Works, Nisshin Steel Co., Ltd. (72) Takeshi Yoshida, 7904 Honami, Bizen-shi, Okayama Koa Fireproof Industry Co., Ltd.

Claims (7)

[Claims] 1. A basic refractory material obtained by mixing slag generated in a steelmaking process of high alloy steel including stainless steel as an aggregate, which is Cr ₂ O ₃ , FeO, MnO, MgO,
An oxide of chromium containing each major component of CaO and SiO ₂ and various crystal type compounds formed in a two-component system or a three-component system between these components, and mainly containing the Cr ₂ O ₃ component 5 to 100% by weight of slag having a chemical composition occupying 35 to 60% by weight of the whole slag as an aggregate
A refractory material containing steel-making slag aggregate, which is obtained by mixing a base material with the rest of the basic refractory raw material aggregate. 2. Cr ₂ O ₃ , FeO, MnO, MgO, C
In addition to the main components of aO and SiO ₂ and various crystal type compounds formed in the two-component system and the three-component system between these components, a small amount of each component produced in the steelmaking process and / or in the steelmaking process A slag having a chemical composition that contains a small amount of each component inevitably mixed, and that the chromium oxide mainly composed of the Cr ₂ O ₃ component occupies 35 to 60% by weight of the entire slag. 5 to 100% by weight as an aggregate
The refractory material containing the steelmaking slag aggregate according to claim 1, wherein the refractory material is a mixture of the basic refractory raw material and the rest. 3. Basicity of slag {(% CaO +% MgO)
/ (% SiO _2)} refractory material formulated steelmaking slag aggregate according to claim 1 or 2 [wt%] is in the range of 1.2 to 3.0. 4. The P ₂ O ₅ component in a small amount of each component inevitably mixed in the steelmaking process is 0.5% by weight or less of the whole slag, according to any one of claims 1 to 3. A refractory material containing the steelmaking slag aggregate described. 5. The S-purity content in a small amount of each component that is inevitably mixed in the steelmaking process is 0.2% by weight or less of the entire slag, according to any one of claims 1 to 4. A refractory material containing steelmaking slag aggregate. 6. A basic refractory material formed by mixing slag generated in a steelmaking process as an aggregate, wherein the slag has the following three chemical compositions and the following three conditions in terms of properties (1) 1000 on the chemical composition. The content of the low melting point substance of ℃ or less is less than 10% by weight, (2) When slag satisfying the condition of the above (1) is used as an aggregate, the fire resistance of the aggregate is SK39 or more. (3) When slag satisfying the condition of (1) above is used as an aggregate, the pulverization rate in the digestibility test by the autoclave treatment of the aggregate {holding (3 atm × 2 hours)} Is 2% by weight or less, the refractory material containing the steelmaking slag aggregate according to any one of claims 1 to 5, which is satisfied. 7. A binding binder with respect to 100% by weight of both aggregates formed by mixing 5 to 100% by weight of slag generated in the steelmaking process as an aggregate and the balance of the basic refractory raw material aggregate. A refractory material in which the steelmaking slag aggregate is compounded according to any one of claims 1 to 6, which is obtained by adding and compounding a total amount of 0 to 5% by weight of an adhesive binder.