JP2003088845A - Treatment method of spent refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment method of spent refractory by which the quantity of the spent refractory to become waste is minimized by removing incorporated metals, sorting crushed particles of the spent refractory containing an infiltrated part and separating and recovering a large quantity of particles of a good quality part of the spent refractory with high precision. SOLUTION: A primary magnetic selection is carried out on the spent refractory to remove the metals and after that, the spent refractory is crushed, screened and further is secondarily magnetically selected with a larger magnetic force than that of the primary magnet selection to separate into a magnetic body and a non-magnetic body and if necessary, it is distinguished by color whether the slug infiltrated layer is existed or not in the spent refractory of the selected nonmagnetic body to separate into one having the infiltrated layer and one having no infiltrated layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a used refractory for recovering the used refractory in an iron factory and reusing it as a raw material for the refractory.

[0002]

2. Description of the Related Art Conventionally, refractory materials such as refractory bricks and unshaped refractory materials are lined in refining furnaces such as converters and electric furnaces, ladle, gutters, etc., and incidental equipment in steel mills. The refractories are worn out due to melting loss due to molten steel or slag, and new refractory is replaced when the remaining thickness becomes thin.

The refractory generated by this re-attachment has a metal layer adhered to the surface, or a metal layer, iron oxide, slag, etc. infiltrate and a deteriorated infiltration layer adheres.

Since the quality of the infiltration layer such as melting resistance and strength is deteriorated, it becomes an obstacle when reusing the collected used refractories, and most of them are treated as waste.

However, in recent years, there have been problems that the disposal place of these used refractories is restricted, and the disposal processing cost becomes high due to the recovery and transportation costs for disposal.

As a countermeasure against this, Japanese Patent Laid-Open No. 8-188475
As described in Japanese Patent Publication, relatively good things such as porous plugs used in steelmaking plants and refractory linings in ladles were separated and recovered, and the refractory contacted with bare metal and slag. It has been practiced to remove the infiltrated layer and crush only the good quality part to adjust the particle size, and then mix and reuse new granular and powder refractory raw materials.

[0007]

However, according to the method described in Japanese Patent Laid-Open No. 8-188475, a pile of used refractories is used to remove a substance having a small infiltration layer in contact with a metal or slag. It is necessary to select and collect them, which requires time and effort for collection work and separation management, and the refractory to be separated and collected is limited to the lined refractory such as porous plug, ladle, and tundish.

Moreover, it is necessary to remove the infiltrated layer in which the used refractory and the ingot or slag are in contact with each other while observing the boundary. Most of this work requires manual work, so that the infiltrated layer must be removed. It takes a lot of time and labor, and it is difficult to dispose of a large amount of used refractories in the steel factory.

As described above, in the conventional method for reusing used refractory materials, limited refractory materials are targeted, the treatment cost is high, and large-scale treatment is not possible. There is a problem that it is difficult to minimize the amount of used refractory generated.

The present invention has been made in view of the above-mentioned circumstances, and in the processing step, the crushed particles of the used refractory material including the ingot and the infiltrated layer portion are removed, and the crushed particles of the used refractory portion of the good quality portion are removed. It is an object of the present invention to provide a method for treating a used refractory, which enables the separation and recovery of a large amount of treatment with high accuracy and minimizes the amount of the used refractory that becomes a waste.

[0011]

In order to achieve the above object, the gist of the present invention relating to a method for treating a used refractory material is as follows: (1) A primary magnetic separation is performed on a used refractory material. After removing the base metal, crushing and sieving, with a larger magnetic force than the primary magnetic force selection for each particle size,
A method for treating a used refractory material, which is characterized by performing secondary magnetic separation to classify the material into a magnetic material and a non-magnetic material, (2) a used refractory material classified as a non-magnetic material into a refractory raw material. (1) The method for treating the used refractory material according to (1), (3) the presence or absence of a slag infiltrated layer in the selected refractory material of the non-magnetic material is colored. (1) A method for treating a used refractory material described in (1), characterized in that the slag infiltrating layer is classified into those having no slag infiltrating layer and those having an infiltrating layer; The method for treating used refractory as described in (3), characterized in that the used refractory classified as no-use is reused as a refractory raw material, (5) as a magnetic material, or with a slag infiltration layer. Used refractories classified as present were melted, cooled and solidified It is characterized in that it is reused as a raw material for landscape materials or a raw material for refractory materials after being molded without being melted, as a raw material for subsequent refractory materials (1) or (3).
The method for treating used refractories is described.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments embodying the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.

Here, FIG. 1 is a flow chart of a method for treating a used refractory for the purpose of recycling according to an embodiment of the present invention.

Refractory lined in refining furnaces such as converters and electric furnaces used in steel mills and ladles, incidental equipment such as gutters, etc., suffers melting damage and wear, and the remaining thickness becomes thin, leading to the end of life. It is dismantled and replaced. The used refractory that has been dismantled and collected has a surface ingot adhered to it, and a part of the infiltrated layer that has been altered is present, which impedes reuse.

The inventors of the present invention have found that metal is mixed,
As a result of intensive research on the treatment of used refractories with a deteriorated infiltrated layer, as a result of completely removing the mixed metal, there is a good deteriorated layer and a defective deteriorated layer. The crushed particles of the used refractories can be separated and collected in a large amount with high accuracy, minimizing the amount of used refractories that become waste, and reusing most of the used refractories as refractory raw materials. The inventors have found that they can be used and have completed the present invention.

Hereinafter, a method for treating a used refractory material according to an embodiment of the present invention will be described in detail. Note that FIG.
In order to facilitate understanding, the numbers shown in are assigned to the respective treatment steps and refractories described below.

The dismantled used refractories 1 are alumina type, magnesia type, alumina / silica type, zircon type, magnesia / carbon type, alumina / carbon silica / carbon type, etc. It is separated into 1 to 300 tons each time. The used refractory materials that have been separated and collected are collected in the same main component system, and proceed to the primary magnetic separation 3 for the purpose of removing the mixed metal 2. The dismantled refractory contains a large amount of metal that adheres to the surface or is inserted into the cracks of the refractory, but when this metal is mixed in the recycled refractory raw material, When a refractory is used in a steel factory, etc., it will form a compound with an extremely low melting point due to the temperature load during use, resulting in a significant decrease in life compared to a refractory containing only new raw materials. This is to prevent it from happening. The magnetic flux density to act as the primary magnetic force selection 3 is preferably 1,000 to 5,000 gauss. If it is less than 1,000 Gauss, even if the unrestricted metal can be removed, it will not adhere even to the refractory or even the metal inserted. On the other hand, if it exceeds 5,000 gauss,
This is because a part of the used refractory having a layer infiltrated with slag containing a large amount of iron oxide component is also removed in a state of being mixed with the metal. A suspension type magnetic separator or a drum type magnetic separator is suitable as the device for primary magnetic force selection, but is not limited thereto. In the primary magnetic selection, the used refractory material may be roughly crushed in advance with a breaker, a jaw crusher, or the like into a size suitable for the work.

The used refractory material subjected to the primary magnetic force selection is crushed into a size of 60 mm or less 4 by using a crushing device for mass treatment such as a commonly used jaw crusher, double roll crusher, or glass cone, 4 Using a vibrating sieving device or the like, sieving 5 is performed for each specific particle size according to the purpose of reuse. For example, 60 to 20 mm, 20 to 20
It can be divided into 10 mm, 10 to 5 mm, and 5 mm or less. Here, the particle size after crushing is set to 60 mm or less in order to suppress the generation ratio of the one containing the infiltration layer to the crushed, lump and granular used refractory material as much as possible. Further, classification after crushing is carried out in advance as a necessary pretreatment in order to enhance the work efficiency of the subsequent steps.

The used refractory in the form of lumps and granules can be divided into two types by using a device having a magnetic force larger than that of the primary magnetic force sorting device such as a belt type magnetic force sorting device or a counter electrode type magnetic force sorting device for each grain size. Next, magnetic force selection 6 is performed to classify the magnetic material into a non-magnetic material 7 and a magnetic material 8. This is because the infiltrated layer in which molten iron and slag have infiltrated reacts with the refractory raw material forming the refractory to form a compound containing iron oxide, and contains an iron oxide component, so that it has a weak magnetic property. It takes advantage of that. The higher the content of the infiltrated iron oxide component, the lower the refractory temperature of the refractory material.Therefore, when reusing the used refractory material, as much as possible, lumps with an infiltration layer and granular used refractory materials It is necessary to control the mixture of substances.

As a result of intensive studies, the present inventor has found that the content of the iron oxide component contained in one lump or granular used refractory is slightly different depending on the main component and the particle size of the used refractory. It has been found that if the content is 0.4 mass% or less, even if this used refractory is reused as a refractory raw material, the durability will not be deteriorated, and it will not be a factor of shortening the life during reuse. From the survey results shown in Fig. 2, the limit content of iron oxide contained that can be removed from the used refractory can be reduced as the magnetic flux density increases, and the secondary content can be obtained at a magnetic flux density of 10,000 gauss or more. It was found that the content of iron oxide can be reduced to 0.4% by mass or less by performing magnetic separation.

In general, a used refractory containing no carbon has a relatively thick infiltration layer as compared with a used refractory containing carbon, because the effect of making it difficult for carbon to wet slag and the like cannot be exhibited. large. Therefore, in consideration of the variation in the accuracy of secondary magnetic force selection, the absolute weight of the magnetic substance (with the infiltration layer) mixed in the non-magnetic substance (without the infiltration layer) per unit treatment weight does not contain carbon. Refractory is higher. In addition, some of the used refractory materials containing carbon have no infiltration layer and are non-magnetic materials, but some carbon materials are oxidized and the refractory structure deteriorates. .

Some operating conditions are strict, and strictness is required for the chemical composition of the refractory lining. For the purpose of further stabilizing the reuse of the used refractory, these defective materials that affect the durability are It may be necessary to further remove the used refractory.

The inventors of the present invention have earnestly studied a method of additionally removing a material containing an infiltrated layer or an oxidized layer for the purpose of further safe reuse of used refractory materials, and as a result, these color differences are utilized. By doing so, they found that they can be identified automatically. This is because the used refractory that does not contain carbon is white in the part without the infiltration layer, but the part of the infiltration layer is black, and in the used refractory containing carbon, the original color is black, but the oxidized part is white. By utilizing the fact that it can be identified.

The used refractories subjected to the secondary magnetic force selection for each particle size are subjected to color selection 9. Explaining an example of the configuration of the color selection device, the color information of the object to be rejected is installed in the computer in advance, the color information of the object that continuously flows on the belt conveyor is identified by the camera, and the object to be rejected passes. It is a method of blowing off with an air gun when doing. By using this type of color sorter, only used refractories containing defective parts conveyed on the belt conveyor together with used refractories consisting of good quality parts will be knocked down near the drop point. Thus, the defective portion can be almost completely removed, and almost all the used refractory material of good quality remains in the used refractory material that has been housed in the chute without being knocked down near the drop point.

Used refractories 7 and 10 composed of good quality parts which have been subjected to secondary magnetic force selection, and further color selection as necessary, and have been classified as having no slag infiltration layer are aggregates of castable and press-in pouring materials. , Or fireproof material for spraying construction,
Used as a refractory raw material for refractory bricks.

On the other hand, the used refractories 8 and 11 containing the defective portion classified by the secondary magnetic force selection and further the color selection as necessary and classified as having the slag infiltration layer or the oxidation layer are infiltrated. By melting 14 and 15 together with the carbonaceous material to reduce the iron oxide contained in the layer, a dense and low iron oxide content is produced, and the refractory raw material 16 and
Reuse as 17. Alternatively, as a raw material 18 or 19 of a landscape material that is molded by a pressing device, an interlocking block device, etc. without being melted, or gutter sand, a tundish seal material, a tundish dam block, a TPC iron mouth cover material, etc. Refractory raw materials of low quality to be installed in non-important parts that do not reach the life factor of refining furnaces and ladles, gutters, etc. lined with refractory and life of auxiliary equipment in factories 2
Reuse as it is as 0 and 21.

This method of treating used refractories enables large-scale treatment of used refractory and reduction of treatment cost.
Moreover, most of the used refractory materials can be effectively reused, and the refractory materials to be discarded can be minimized to avoid environmental problems such as landfill.

[0028]

EXAMPLES Next, examples of a method for treating a used refractory material according to the present invention will be described.

Alumina castable 2 containing 85% by mass of Al ₂ O ₃ lined in a ladle used for transporting molten steel.
In order to replace it, 0 ton was disassembled with a pick breaker and collected, and further roughly crushed to a size of a human head. Figure 3
Shows the treatment process flow, the balance balance of the used refractories sorted and collected in each process, and the content ratio of iron oxide analyzed by fluorescent X-ray. First, the used refractory material was subjected to primary magnetic force selection using a suspension type magnetic force selection device having a magnetic flux density of 3500 gauss. As a result, the total amount of 1.8 tons of the metal that was mixed could be selected as a magnetic material. The non-magnetic material classified by the primary magnetic separation and composed only of the used refractory is crushed to 60 mm or less by the jaw crusher, and then the vibrating and sieving device is used, and the particle size is 60 ~.
It screened so that it might become 20 mm, 20-5 mm, and 5 mm or less. And 60 ~ 20mm, 20 ~ 5mm,
For each grain size, a magnetic flux density of 12000 gauss was applied to a belt type magnetic force sorting device and 5 mm or less was applied to a counter electrode type magnetic force sorting device of 28,000 gauss to sort into magnetic substance and non-magnetic substance. Here, only the used refractory with a particle size of 5 mm or less was applied to the counter electrode type magnetic separator because a large amount of fine particles with a particle size of 1 mm or less were also included. The reason is that although it is a non-magnetic material, it is thrown into the chute of a magnetic material, and it is determined that correct sorting is difficult, and the drop method is considered to be more suitable.

Further, except for the particle size of 5 mm or less, the particles were subjected to a color sorter and classified into particles containing a wetting layer and particles not containing a wetting layer. The color sorter is equipped with one CCD camera, the width of the belt conveyor is 300mm, and 30 air guns are lined up in a row of 300mm width. At a speed of 80 m / min, originally white ones formed an infiltrated layer and were classified by being darkened to be identified. In Fig. 3, after color selection, the infiltration layer mixed in the used refractories classified without the infiltration layer was obtained by manual selection, and the ratio of the used refractory excluding it was shown as the pass rate. However, by performing color selection, it is possible to raise the pass rate to 99.9% for any particle size, and there is no need to worry about the influence of the iron oxide content. Here, what was not applied to the particle size of 5 mm or less is the secondary magnetic force selection, which is less than the target value of 0.4 mass% of the iron oxide component contained in the used refractory which is already recycled for reuse. Therefore, even if you apply color selection, the particle size is fine, the processing capacity is extremely low, compared to other particle sizes, and the level of the decomposed image of the camera and the air gun injection against the particle size of the used refractory This is because it was judged that the probability of selective removal due to was low, and high-accuracy sorting was impossible.

The used refractory material having a grain size of 60 to 20 mm, which is judged to have no infiltration layer by secondary magnetic force selection and color selection, is a brown-alumina coarse aggregate of a press-in pouring block installed in a ladle floor. As an alternative to the above, when 60% by mass of the inner coat was added and reused, the filling state was good, and the life was not shortened as compared with the normal product.

Grain size 20-5 m judged to have no infiltration layer
The used refractory of m is 25 mass% of inner lining, as an alternative to the brown alumina coarse aggregate castable for ladle general walls.
When added and reused, the workability and filling state were good, and the same life as regular products was secured.

A used refractory having a particle size of 5 mm or less, which was judged to be a non-magnetic material by secondary magnetic screening, was added with 40% by mass of the inner coating as a repair material for dry spraying and reused. It was possible to secure durability equivalent to that of normal products without causing deterioration of

On the other hand, the used refractories having a grain size of 5 mm or less, which are judged to be magnetic substances by being subjected to secondary magnetic force selection, are piled up in buckets, and when 2 tons are accumulated, every one hour,
Divided into 4 times, charged with coke powder as carbonaceous material into an arc type melting furnace and subjected to arc heating at 2500 to 3000 ° C., and about 70 mass% of the total amount of the used refractory materials charged was melted. By the way, after heating was stopped and natural cooling was carried out, the solidified melted ingot was taken out and crushed, and then magnetic separation of 3000 gauss was carried out to remove the reduced metallic iron. As a result, the content of iron oxide, which was 6.2 mass% before melting, decreased to 0.2 mass% in the ingot, and a good refractory raw material could be obtained.

Those which are determined to be magnetic substances by the secondary magnetic force selection,
And the grain size 6 which was judged to have an infiltrated layer by applying color selection
Used refractory of 0 to 20 mm is reused as an aggregate of landscape material blocks, kneaded with fine Portland cement and blast furnace slag powder, and molded with an interlocking block device, and marketed as an inexpensive landscape material. Is being supplied to.

Those which are determined to be magnetic substances by the secondary magnetic force selection,
And the grain size 2 judged to have an infiltrated layer by applying color selection
Used refractory of 0 to 5 mm was added as a castable aggregate for gutter covers with 20% by weight of inner lining and reused. It did not interfere with the operation and was more durable than ordinary products. No decline was seen.

The embodiment of the present invention has been described above.
The present invention is not limited to the above-described embodiment, and changes in conditions and the like without departing from the spirit are all within the scope of application of the present invention.

[0038]

EFFECTS OF THE INVENTION According to the present invention, after the mixed metal is completely removed from the total amount of the used refractories generated and recovered in the steelmaking plant, the non-magnetic material, the magnetic material and the infiltrating layer are separated for each grain size. It has become possible to automatically sort out those that include and those that do not, with high processing capacity. By recycling according to the form and characteristics of the selected used refractory, the reuse ratio, which was 3% in the past, could be increased to 99.9%. In particular, even when it was not reused as a refractory raw material, compared with the conventional refractory to which the used refractory was not added, the life was not shortened and the equivalent durability could be secured. Along with this, the cost of refractories used in the steel plant could be reduced by about 20%, and the amount of waste for landfill could be reduced to zero throughout the year.

[Brief description of drawings]

FIG. 1 is a flowchart of a method for treating a used refractory material according to an embodiment of the present invention.

FIG. 2 is a relationship diagram of iron oxide content-magnetic flux density contained in a non-magnetic material after secondary selection.

FIG. 3 shows the balance of balance and iron oxide content for each treatment process of used refractories.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) B07B 1/28 C04B 35/66 S 4G030 B09B 3/00 G01J 3/51 4G033 C04B 35/00 G01N 21/27 B 4K001 35 / 66 C22B 1/00 601 G01J 3/51 B09B 5/00 ZABF G01N 21/27 C04B 35/00 V // C22B 1/00 601 B09B 3/00 Z 303A (72) Inventor Matsui Taijiro Tobata, Kitakyushu, Fukuoka Prefecture 1-1 Hiwata-cho, Hinohata-ku, Tokyo (72) Inventor Hiroshi Imagawa 1-1 Hibata-cho, Tobata-ku, Kitakyushu, Kitakyushu, Fukuoka 1-1 In-house, Yawata Works (72) Person Tetsuo Shima 20-1 Shintomi, Futtsu City, Chiba Prefecture Nippon Steel Co., Ltd.Technology Development Division (72) Inventor Hiroyuki Kato 20-1 Shintomi, Futtsu City, Chiba Prefecture Nippon Steel Co., Ltd.Technology Development Headquarters (72) Invention Takeshi Matsuda 5-3 Tokai-cho, Tokai-shi, Aichi Nippon Steel Share company Nagoya Steel Works (72) Inventor Toshifumi Suzuki Tokai-cho, Tokai-shi, Aichi 5-3 Shin Nippon Steel Share company Nagoya Works (72) Inventor Seiji Aso Oita-shi Oita-shi 1 Nishinosu New Nippon Steel Co., Ltd. Oita Steel Works (72) Inventor Shiro Yusei 1st Nishinosu, Oita City, Oita Prefecture Shin-Nippon Steel Co., Ltd. Oita Steel Works F Term (reference) 2G020 AA08 BA20 DA05 DA13 DA66 2G059 AA05 BB09 EE02 EE13 HH02 JJ02 KK04 4D004 AA16 BA05 BA06 CA04 CA08 CA09 CA29 CA32 CB13 DA03 4D021 CA07 EA10 EB01 4D067 EE14 EE17 EE25 GA20 GB05 4G030 AA36 BA25 4G033 AA02 AA11 AB02 BA01 4K001 AA10 BA22 CA04

Claims (5)

[Claims] 1. The used refractory is subjected to primary magnetic sorting to remove the metal, and then crushed and sieved. A method for treating used refractories, which is characterized by performing the following magnetic separation to classify it into a magnetic substance and a non-magnetic substance. 2. The method for treating a used refractory according to claim 1, wherein the used refractory classified as a non-magnetic material is reused as a refractory raw material. 3. The used refractory of the non-magnetic material selected is further distinguished by color for the presence or absence of a slag infiltration layer,
The method for treating a used refractory material according to claim 1, characterized in that it is classified into one having no slag infiltration layer and one having an infiltration layer. 4. The method for treating a used refractory according to claim 3, wherein the used refractory which is a non-magnetic material and is classified as having no slag infiltration layer is reused as a raw material for the refractory. . 5. A landscape material for use as a refractory material after melting and cooling and solidifying a used refractory material classified as a magnetic material or a material having a slag infiltrating layer, or for forming a landscape material. 4. The method for treating a used refractory according to claim 1 or 3, which is reused as a raw material or a refractory raw material.