JPH10130066A - Production of casting material using alumina based refractory waste material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an alumina based casting material to which an alumina based refractory waste material obtained by a refractory waste material treatment without causing any deterioration of workability and durability is added in order to use the casting material using the alumina based refractory waste material used for a lining refractory of a vessel for molten metal. SOLUTION: The refractory waste material containing >=60% Al2 O3 is particle-sized into 1-50mm, dipped into a metallic alkoxide solution containing a sol solution of metal oxide or a precursor of the metal oxide to impregnate the surface of the refractory waste material with >=0.5wt.% metal oxide and dried. The treated refractory waste material of 5-30wt.% is added into the alumina based casting material. Since the metal oxide having heat resistance is impregnated into the particle-sized refractory waste material, the alumina based refractory waste material is effectively used as the coarse particle of the alumina based casting material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a refractory waste material which does not cause deterioration in workability and durability because a cast material using an alumina-based refractory waste material is used for a refractory lining of a container for molten metal. The present invention relates to a treatment method and a method for producing an alumina-based cast material to which an alumina-based refractory waste material obtained by the method is added.

[0002]

2. Description of the Related Art Heretofore, refractory linings in used molten metal containers and the like have been almost discarded after being dismantled, and only a part of them has been sorted and crushed and reused. Also, most refractory members used for casting, such as long nozzles, immersion nozzles, and sliding plates, have been similarly discarded. For this reason, there has been a strong social demand for recycling such waste materials into refractories.

On the other hand, the construction of the refractory-lined structure is mainly performed by using a casting material, particularly for reasons such as mechanization and labor saving of furnace construction work. In recent years, hot metal pots,
The main flow of refractories lined in a molten iron processing vessel such as a ladle, RH, and tundish is an alumina-based pouring material.

[0004] Refractory casting members such as immersion nozzles, and bricks such as lining of mixed iron wheels are alumina-based refractories mainly containing carbon. It is satisfactory if these alumina-based refractory waste materials can be used again for the production of refractories, and if they can be used as resources for casting materials, the above requirements will be met, which is very convenient from this viewpoint. .

However, when these waste materials are added to the cast material, the flowability, water absorption, crushability and the like greatly affect the properties of the product, unlike the addition to the bricks. You cannot use it. Furthermore, the agglomerates themselves obtained by pulverizing the waste material are inhomogeneous and porous, so that they have high water absorption. For this reason, if these waste material agglomerates are used directly as a casting material, due to their large water absorption or the like, unevenness of the material occurs, or quality deterioration such as poor filling property is caused, and the waste material can be used as a raw material. There was a limit, and could not be fully utilized.

As a countermeasure, Japanese Unexamined Patent Publication No. Hei 6-345548 discloses a method in which, before blending a remnant of refractory waste with a refractory raw material, kneading with a mortar and water in advance and coating the surface of the remnant with mortar. , It is suggested to be used as a pouring material.

[0007]

However, this method can be applied only to aggregates having a particle size of 10 mm or more, and a mortar having a high air permeability cannot suppress the strengthening of the carbon source contained in the waste material. Occasionally, the refractory structure deteriorates. In addition, there is a problem that the thermal shock resistance decreases due to oversintering between the mortar coated with the agglomerates of the waste material and the refractory raw material, and the corrosion resistance decreases due to a reaction of forming a low melting point between the mortar and the refractory raw material. I was The present invention solves the above problems,
The main purpose is to effectively utilize alumina-based refractory waste material as coarse particles of an alumina-based casting material.

[0008]

Means for Solving the Problems The present invention has been made to solve the above problems, and the means are as follows. (1) A refractory waste material having an Al ₂ O ₃ content of 60% by weight or more is sized to 1 to 50 mm, and then immersed in a metal oxide sol solution to form a metal oxide on the surface of the refractory waste material. 5
A method for producing a cast material using an alumina-based refractory waste material, wherein the impregnated refractory material is dried after being impregnated in an amount of not less than 5% by weight, and the treated refractory material is subjected to the above treatment. . (2) A refractory waste material having an Al ₂ O ₃ content of 60% by weight or more is sized to 1 to 50 mm, then immersed in a metal oxide sol solution, and then immersed in a metal alkoxide solution containing a metal oxide precursor. Immersing, impregnating the surface of the refractory waste material with a metal oxide in an amount of 0.5% by weight or more, drying the refractory waste material, and adding the treated refractory waste material to 5 to 30% by weight alumina-based casting material. A method for producing a casting material using a waste alumina-based refractory material.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In view of the problems of the prior art, the present inventors have eagerly considered that a fine and thin layered structure may be formed with fine particles on the surface of waste material. After repeated research, 1-50mm of alumina waste material
Before being mixed with an alumina-based refractory raw material, before being impregnated with a heat-resistant metal oxide sol solution or a metal alkoxide solution containing a metal oxide precursor, and then dried. Have found that the agglomerates of the waste material are effective as coarse particles of the cast material, and as a result, the refractory waste material can be utilized, and the present invention has been completed.

That is, according to the present invention, as a method for treating alumina-based waste material, the waste material is sized to 1 to 50 mm, and then A
A sol solution of a heat-resistant metal oxide such as l ₂ O ₃ , SiO ₂ , or ZrSiO ₄ is impregnated with the waste material so that the metal oxide is impregnated to 0.5% by weight or more in air or under vacuum.
After immersion for more than a minute, preferably several hours, it is dried at 200 ° C. or less.

[0011] Alternatively, as a method of treating alumina-based waste material, the waste material is sized to 1 to 50 mm, and then Al ₂ O ₃ ,
In a metal alkoxide solution containing a precursor of a heat-resistant metal oxide such as SiO ₂ or ZrSiO ₄ , the surface of the waste material is impregnated with the metal oxide to 0.5% by weight or more under the atmosphere or under vacuum. After immersion for more than a minute, preferably several hours, it is dried at 200 ° C. or less. By performing such a treatment, coarse particles of 1 to 50 mm in which the surface of the alumina-based refractory waste material is coated with a metal oxide are obtained, and this is added to the alumina-based casting material as a base material in an amount of 5 to 30% by weight. It is to be added.

Hereinafter, the present invention will be described in more detail. According to the method of the present invention, Al ₂ O ₃ , Si
An alumina-based waste material impregnated with a heat-resistant metal oxide such as O ₂ or ZrSiO ₄ can be obtained. That is, the waste material is crushed by a normal crusher such as a crusher,
The mixture is sieved to obtain granules having a particle size of 1 to 50 mm. Preferably, further 1-5 mm, 5-10 mm, 10-20 m
It is better to sieve finely to 20 to 40 mm, and to make the mixing ratio of each particle size approximate to the particle size configuration of the casting material as the base material. When the particle size is 1 mm or less, it is not preferable to add an alumina-based waste material impregnated with a metal oxide to the casting material because an abnormal reaction or abnormal expansion may occur. When the particle size is 50 mm or more, the segregation of the particles may occur at the time of construction or the structure of the fine particles filled between the coarse particles may become loose and the stability as a structure may be reduced, which is not preferable. .

The waste material used has an Al ₂ O ₃ content of 6
It is an alumina-based refractory of 0% by weight or more, and an Al ₂ O ₃ content of 60% by weight or less impregnated with Al ₂ O ₃ and SiO <sub>2.
2. Because</sub> the metal oxide such as ZrSiO ₄ and the waste material themselves may form a low-melting substance in a high-temperature atmosphere in contact with the molten iron and the molten slag, and the durability may be significantly reduced. Further, it is desirable to use a waste material which has been sufficiently dried by performing a drying treatment. Watery,
This is because the wet solution makes it difficult for the processing solution to impregnate the inside.

Next, the waste material is immersed in a sol solution of a metal oxide having heat resistance or a metal alkoxide solution containing a precursor of the metal oxide. Here, the metal oxide is
Determined by the intended use of the pouring material that mixes the waste material. For example, a portion in contact with high-temperature slag is Al ₂ having corrosion resistance.
The O _3, Z is the site of an oxidizing atmosphere having an Al ₂ O ₃ and SiO ₂ and the intermediate characteristic when the SiO ₂ which acts as blocking air vitrifying the surface of the construction member, is in the both environments
It is desirable to apply rSiO ₄ .

According to one preferred embodiment of the present invention, the sized waste material is transferred to a mesh basket and placed in a container containing a metal oxide sol solution or a metal alkoxide solution containing a metal oxide precursor. And soak. The atmosphere may be in the atmosphere, or the container may be placed in a processing tank maintained in a vacuum state and immersed in a vacuum. This state is maintained for about one hour to perform the metal oxide impregnation treatment.
Depending on the waste material, a short impregnation treatment of just over 10 minutes may be sufficient.

However, when the metal oxide impregnated on the surface of the waste material is not 0.5% by weight or more, the immersion time is further extended. The reason for this is that if the impregnated metal oxide is less than 0.5% by weight, the water absorption of the waste material cannot be prevented, and the workability deteriorates.
As a result, the refractory properties may be reduced, and especially in the case of waste materials containing carbon, carbon may be oxidized at the time of drying and preheating after casting, and the durability may be significantly reduced. After the impregnation, the net basket is taken out of the container, drained, and dried at a temperature of about 150 ° C. When dried at a temperature higher than 200 ° C., the layered film of the metal oxide coated on the surface of the waste material is broken by the influence of the water vapor pressure, and the prevention of water absorption of the waste material is diminished. There is a possibility that the oxidation resistance of itself will not be improved.

Next, the waste material composed of the agglomerates covered with the above-mentioned metal oxide is subjected to water kneading with the pouring material. The pouring material is composed of, for example, an alumina raw material, an alumina spinel raw material, high alumina cement, and an additive such as a deflocculant. The cast material of the present invention varies depending on the desired use / characteristics, the used waste material, etc., but is not uniform. However, the waste material which has been sized and treated by the above method is added to the cast material as a base material by 5 to 30% by weight. It is to be added. If the treated waste material is less than 5% by weight, the effect of improving the workability and characteristics is not clearly seen, and the cost of the cast material is not superior in consideration of the disposal cost of the waste material. Further, when the treated waste material exceeds 30% by weight, the influence of the impregnated metal oxide itself can be seen, resulting in poor construction or deterioration in properties such as corrosion resistance to molten iron and slag and high-temperature strength. This is because remarkable.

[0018]

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention. (Example A) A molded article was produced from a casting material using a composition as shown in Table 1. The carbon-containing refractory waste used here was obtained by collecting and grinding and sieving an alumina-based tundish SN plate having an Al ₂ O ₃ content of 85% by weight. This sieved 1-40m
m was immersed in a silica sol solution and a zircon alkoxide solution for a predetermined period of time.
Drying was performed at ° C. When the untreated waste material was added to Comparative Example 1 where no waste material was added, construction failure occurred in Comparative Example 2 with the same amount of kneading water, and apparent porosity increased remarkably in Comparative Example 3 in which the water content was increased. And a decrease in compressive strength is seen,
The physical properties of the refractory have been reduced. On the other hand, in Examples 1, 2, 3 and 4 in which the waste material was treated, regardless of the silica sol solution and the zircon alkoxide solution, the impregnation under the atmosphere and under vacuum, the workability was equivalent to that of Comparative Example 1 with no waste material added. It is clear that it has the properties of refractories. However, in Comparative Example 4 in which the impregnation time was short, the effect of waste material treatment was small, and construction failure occurred. This is because the impregnation amount of SiO ₂ was less than 0.5%.

[0019]

[Table 1]

(Example B) A molded article was prepared from a casting material using a composition as shown in Table 2. The carbon-containing refractory waste used here is an alumina-based tundish SN plate having an Al ₂ O ₃ content of 85% by weight.
Further, as a method of treating the waste material, the waste material was immersed in a silica sol solution and a zircon alkoxide solution in the atmosphere. Examples 1, 2 and 2 in which the waste material was applied to Comparative Example 1 in which no waste material was added
Regardless of the processing solution, the amount of waste material added is 5 to 30 for both 3 and 4.
In the range of%, there is no decrease in workability, material properties, and refractory properties. Therefore, when applied to a molten iron treatment tank, the same durability as Comparative Example 1 can be expected. On the other hand, in Comparative Example 2 in which the amount of waste material added was small, the effect of the waste material treatment was uncertain, and in Comparative Example 3 in which the amount of waste material added was large, poor construction occurred. Examples 2 and 4 were separately integrated into a ladle wall in contact with molten steel. In both cases, there was no problem in the construction, and a good construction structure was obtained. No cracks or peeling after drying,
Put into production. As a result of the application, the same furnace life as Comparative Example 1 was maintained, the damage rate was equal, and good durability was obtained.

[0021]

[Table 2]

(Example C) A molded article was prepared from a cast material having a composition as shown in Table 3. The waste materials are the limestone brick used for the ladle, the alumina-silicon carbide-carbon brick used for the mixed iron wheel, and the alumina refractory used for the tundish SN plate.
₂ O ₃ content is different. The waste material was treated by immersing it in a silica sol solution. In comparison with Comparative Example 1 in which no waste material was added, Examples 1, 2 and 3, in which the waste material was treated, had the same workability regardless of the type of the waste material, and there was no difference in the physical properties of the refractory. . However, Al ₂ O contained in waste materials
_{(3) The} higher the content, the more the corrosion resistance and the heat-resistant spall properties tend to be improved. In Example 1, in which the content of Al ₂ O ₃ is the lowest, the characteristics are significantly reduced as compared with Comparative Example 1. This is because the impregnated metal oxide and the waste material themselves formed a low-melting substance in a high-temperature atmosphere. Thus, in order to effectively utilize the waste material without deteriorating its durability, it is necessary to use the aluminum of the waste material itself. _It is necessary to pay attention to the ₂ O ₃ content,
You must select more than weight percent waste.

[0023]

[Table 3]

[0024]

According to the treatment method of the present invention, metal oxides having heat resistance can be impregnated up to the inside of refractory waste material that has been sized in advance, and alumina-based refractory waste material can be poured into alumina. It can be effectively used as coarse particles of wood. That is, since the surface of the waste material itself is coated with the metal oxide, the water absorption of the waste material is reduced or lost,
In addition, the strength of the waste material itself can be improved. As a result, the cast material to which the waste material is added does not cause a decrease in workability, a decrease in properties and physical properties, and can provide good durability even when applied to an actual furnace.

Claims (2)

[Claims] 1. A refractory waste material having an Al ₂ O ₃ content of 60% by weight or more is sized to 1 to 50 mm, and then immersed in a metal oxide sol solution to deposit a metal oxide on the surface of the refractory waste material. A cast material using an alumina-based refractory waste material, wherein the impregnated refractory material is dried after impregnated by 0.5% by weight or more, and the treated refractory waste material is added to a 5-30% by weight alumina-based cast material. Manufacturing method. 2. A refractory waste material having an Al ₂ O ₃ content of 60% by weight or more is sized to 1 to 50 mm, then immersed in a metal oxide sol solution, and then a metal alkoxide containing a metal oxide precursor. After being immersed in a solution, the surface of the refractory waste material is impregnated with 0.5% by weight or more of a metal oxide, dried, and the treated refractory waste material is added to 5 to 30% by weight alumina-based casting material. A method for producing a casting material using an alumina-based refractory waste material.