JPH11117012A - Production of low alloy steel using waste car scrap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize valuable metals, such as Ni, Cr, Mo, Cu, etc., contained in waste vehicles. SOLUTION: The waste car scrap obtd. by executing press-forming after applying safety countermeasure to prevent explosion at the time of charging it into a furnace by beforehand taking out only liquid from almost intact waste vehicle, is charged into a converter to produce a low alloy steel in a low cost by utilizing the special steel components in the waste car scrap 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing low alloy steel using a plurality of scrapped vehicles as scrap, and more specifically, to scrapping a plurality of scrapped scraps obtained by press-forming scrapped vehicles. The present invention relates to a method for inexpensively producing low alloy steel by charging a steelmaking melting furnace represented by a converter.

[0002]

2. Description of the Related Art As is well known, in the operation of steelmaking melting furnaces such as converters and electric furnaces, which are important production techniques in the steel industry, iron scrap is one of the important raw materials. A stable supply of iron scrap has not been established in the future, and some form of solution is required at this time.

[0003] Therefore, while being mass-produced today,
Many attempts have been made to effectively use scrap vehicles, such as scrap cars, whose disposal becomes a problem after use as iron scrap, and some of them are actually used in steel melting furnaces. Used as iron scrap in operations. Hereinafter, the prior arts will be summarized.

(I) Japanese Patent Application Laid-Open No. 3-291331 While recovering all the energy of the resinous residue contained in scrap iron and improving the steelmaking cycle,
This is a method of preheating scrap iron by thermally decomposing this resinous residue. However, in this method, there is a limit suitable for the operation in terms of the size and shape of the scrap iron, and the scrap iron must be cut and used, which increases the pretreatment cost.

(Ii) Japanese Patent Application Laid-Open No. 5-171305 [0005] A desired portion of a waste vehicle is crushed or cut, and the waste vehicle is charged into a continuous heating furnace having a plurality of heating zones having different temperatures. Half-burn the material and recover it as oil,
This is a vehicle disassembly and recovery method in which desired materials are sequentially melted in respective heating zones and separated and recovered. However, in this method, the steps required to recover the scrap iron from the waste vehicle become complicated, and the pretreatment cost increases.

(Iii) JP-A-5-222424 DISCLOSURE OF THE INVENTION Environmentally-friendly disposal of organic and inorganic non-metallic incidental substances of mass-produced products such as waste vehicles or washing machines and refrigerators. In the smelting of iron ore in blast furnace equipment, waste materials are chemically reduced and used as a flux to form slag, or used in the production of steel or cast iron in cupola equipment and usually used as a flux. Supplement at least part of the substance. However, in this method, a dismantling process of the waste vehicle is required, and the pretreatment cost increases.

[0007] Since these prior arts carry out appropriate pre-treatment on the discarded vehicle, the cost of the pre-treatment increases in each case, and the scrap scrap utilization of the discarded vehicle is significantly impaired.
Therefore, the present applicant has proposed some processing techniques in which such preprocessing is suppressed as much as possible.

(Iv) Japanese Patent Laid-Open Publication No. 8-143929 [0008] A substantially original scrap vehicle, which has been subjected to safety measures such as preliminarily extracting liquid from the scrap vehicle and preventing explosion when charging the converter, is used as a scrap for the converter. At the same time, the decarburization is promoted by using the heat of combustion of the rubbery substance or resinous substance contained in the waste vehicle as heat energy.
However, according to this method, since the volume of the scrap increases, if the number of pieces to be charged at once is increased, clogging of the furnace port is likely to occur at the time of charging the converter. Therefore, only one vehicle / CH can be used, and the cost reduction effect cannot be expected much. In addition, the scrap weight is reduced and the scrap balance becomes unstable.

[0009]

Therefore, the present applicant has
First, according to Japanese Patent Application No. 8-350951, the pre-treatment process that causes cost increase such as dismantling of large-sized waste such as scrapped vehicles is omitted so as to minimize it, and the resources of scrapped vehicles can be efficiently recycled. At the same time, in order to prevent the instability of the scrap balance, which is usually controlled by weight, at the time of the production of ordinary steel by the steelmaking melting furnace, only the liquid is extracted in advance,
At least two scrap car scraps of approximately 1.0 m square shape are pressed into a steelmaking melting furnace by press forming a nearly prototype discarded vehicle with safety measures such as explosion when charging the furnace. The operation method of the steel melting furnace was disclosed.

According to this operation method, it is possible to use a plurality of discarded vehicles in order to reduce the risk of clogging of the chute, and to make effective use of the heat of combustion of the rubber or resinous material in the discarded vehicles. The cooling capacity can be improved, and ordinary steel can be smelted in the converter.

However, as a result of further studies, the present inventors have found that, according to the technology proposed in Japanese Patent Application No. 8-350951, valuable metals such as Ni, Cr, Mo and Cu contained in discarded vehicles are used. In addition, it has been newly found that the content of these valuable metals in the steel to be smelted is increased, and there is a problem that when the common steel is smelted, the components need to be further adjusted.

Here, an essential object of the present invention is to effectively utilize valuable metals such as Ni, Cr, Mo, Cu, etc. contained in a scrapped vehicle, and to obtain an advantage of the steel smelting technology by loading scrap scrap. Is to establish further.

[0013]

The inventors of the present invention have further studied and found that if the increase in the content of these valuable metals due to the charging of scrap car scrap is effectively used, these valuable metals can be used. The inventors have found that low-alloy steel can be produced at low cost by reducing the amount of positive addition, and completed the present invention.

That is, the present inventors have the advantage that the use of a plurality of discarded vehicles as an inexpensive iron source is advantageous for melting steel in a steel melting furnace typified by a converter, and particularly has an economic advantage. By utilizing valuable metals in discarded vehicles whose component weight% is known in advance to make further use, it is possible to obtain new knowledge that low alloy steel of the target component can be produced at minimum cost, The present invention has been completed.

Here, the gist of the present invention is that a steelmaking melting furnace is prepared by extracting only liquid from a substantially original scrapping vehicle in advance and taking safety measures such as preventing explosion when charging the furnace, followed by press forming. By using at least two or more scraps obtained as a result of scrapping as scrap, low-alloy steel is manufactured at a low cost by using a special steel component in the scraps. This is a method for producing an alloy steel.

In the above method for producing low alloy steel using scrap car scrap according to the present invention, "low alloy steel"
It means a steel that has given properties by adding a small amount of valuable metals such as Ni, Cr, Mo, and Cu to ordinary carbon steel.

In the method for producing low-alloy steel using scrap scrap according to the present invention, the heat of combustion of one or both of the rubbery substance and the resinous substance contained in the scrapped vehicle is used as thermal energy. It is desirable to improve the cooling capacity.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for producing low alloy steel using scrap car scrap according to the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment,
5 discs / CH of a discarded vehicle pressed by 2 normal vehicles / 1 press
(10 cars / CH) This will be described by taking an example of using the vehicle.

FIG. 1 shows a chute 1 (in this embodiment, length: 13 m) when charging scrap scrap 2 into converter 3 (250 ton furnace in this embodiment, furnace diameter d ₀ : 4.2 m). Width: 2.
3m) is a conceptual diagram showing the packing method, FIG. 1 (a) is a front view,
FIG. 1B is a top view. FIG. 2 is a conceptual diagram when charging scrap car 2 into converter 3.

As shown in FIGS. 1 (a) and 1 (b), in the present embodiment, the scrap scrap 2 is arranged in one row and two stages (two in the upper stage and three in the lower stage) on the tip side of the chute 1. ) And charged into the converter 3. On the rear side of the scrap car scrap 2, light waste 4, cold iron 5, and heavy waste 6 are packed in this order, and the impact when the heavy waste 6 is charged into the converter 3 is reduced. As a result, furnace downtime due to local melting of the refractory on the charging side is reduced, and the life of the converter can be improved by about 10 to 17%. The converter 3 is charged with care so as not to cause clogging of the furnace chute.
Therefore, clogging of the furnace port is prevented in advance. This makes it possible to charge 10 vehicles / CH.

From the viewpoint of preventing explosion when the scrap 2 is charged into the converter 3, as a safety measure, liquids such as gasoline, oil, and cooling water are drained from the scrap vehicle, and a fuel tank and a radiator are disposed. Open the closed part such as.

As in this embodiment, when a scrapped vehicle is press-formed without being dismantled to be scrapped scrap 2 and charged into the converter 3 as scrap, a typical value of iron contained in the scrapped scrap 2 is It is as shown in the following formula.

[0023]

[Expression 1] 1.4 (tons / vehicle) × 0.72 (content rate) = 1.0 (tons / vehicle) ····················· Table 1 shows an example of the representative values of the components of all the materials constituting the scrapped vehicle Are shown together.

[0024]

[Table 1]

As shown in Table 1, the iron content in the scrap vehicle is about 72% by weight, including special steel. Also, Table 2 shows an example of special steel components that are included in the scrap vehicle and can be an additional alloy source when the low alloy steel is melted.

[0026]

[Table 2]

Since the weight of various parts varies depending on the type of vehicle, the maximum component increase when using 15 vehicles (15 tons) / ch in Table 2 is 15% of one vehicle (1.4 tons), and all components are the maximum values of components. It is calculated as there is.

In a steel melting furnace typified by a converter, a variety of steels are melted in one furnace. According to the present embodiment, in order to melt a low alloy steel by using this converter, Ni , Cr, Mo, Cu
By blending a large amount of scrap scrap whose weight% of valuable metal components such as is known, it is possible to reduce the amount of valuable metal added for component adjustment in subsequent processes by that much, and to reduce the use of low alloy steel. It can be manufactured at low cost.

As described above, according to the present embodiment, the following effects can be obtained. The cost can be reduced by omitting the pretreatment process for the discarded vehicle. That is, conventionally, a waste vehicle →
Although a pretreatment process of dismantling → sorting → scrap iron → charging the converter had been performed, according to the present embodiment, disposal vehicles → safety measures →
Press molding → converter charging is simplified, and significant cost reduction can be achieved.

[0030] By press-forming a scrapped vehicle,
It is possible to stabilize the scrap balance and increase the usage amount. By effectively burning and burning the rubbery substance (carbon) and resinous substance contained in the waste vehicle, the heat energy can be further increased and the cooling capacity can be increased.

It is possible to reduce the amount of valuable metal added in the smelting of low-alloy steel, and to smelt low-alloy steel at low cost. It becomes possible to economically and efficiently process a large amount of waste vehicles that are industrial wastes.

Further increase the recycling of scrapped vehicles
Can be promoted. Further, a method for producing low alloy steel using scrap car scrap according to the present invention will be described more specifically with reference to practical data.

[0033]

[Example] A scrap car obtained by pressing a scrap car using a 250 ton converter was used for 5 car / ch, 10 car / ch, and 15 car / ch.
The converter was operated using ch. At this time, the scrap scrap used was prepared by extracting only the liquid in advance, taking safety measures such as preventing explosion at the time of charging, and then pressing to reduce the volume.

(1) Transition of components of special steel components Table 3 summarizes the transition of components of main special steel components in this example. In Table 3, the difference from the conventional example without scrap car scrap is the reduction in alloy addition in the smelting of low alloy steel,
That is, it means the amount of cost reduction related to the production of low alloy steel according to the present embodiment.

[0035]

[Table 3]

(2) Results of production of low alloy steel Tables 4 to 6 show the results of alloy addition amounts in the smelting of low alloy steels in comparison with the conventional example, in Examples 1 to 3 of the present invention.
It shows about each.

[0037]

[Table 4]

In Example 1 shown in Table 4, since the target component value of Cr has an upper limit of 0.05%, the composition of scrap scrap is limited to a maximum of 15 tons / ch. According to the first embodiment,
The alloy addition cost was reduced by about 15%.

[0039]

[Table 5]

In Example 2 shown in Table 5, scraps of scrap scrap were blended at 25 tons / ch in order to recover all components of Cr and Cu from valuable metals in scrap scrap. The shortfall in the target components of Ni and Mo was dealt with by adding alloys.
A 33% reduction was achieved.

[0041]

[Table 6]

In Example 3 shown in Table 6, since the target component value is high, the cost merit increases as the mixing ratio of scrap scrap increases, but this time, in consideration of the scrap balance, the scrap scrap in a 250-ton converter is used. 10
%, That is, 25 tons / ch of scrap car scrap was blended. However, since the scrap car scrap blending ratio can be operated in the range of 0 to 30%, the blending ratio of the third embodiment is not limited to 10%, but is, for example, 10% on average among several charges. It is desirable to select the operation that maximizes the cost merit by changing the mixing ratio for each charge so that the mixing ratio becomes.

(3) Converter operation It was confirmed that troubles such as clogging did not occur at the time of charging the scrap, and that the operation could be performed safely without generating dust or explosion at the time of charging the hot metal.

(4) Dust Collection Dust components sampled from the primary dust collection water of the converter were compared for normal operation and when 25 vehicles / ch were used, but there was no difference between the two. Even if the vehicle / ch was used, the effect was within the range of the dilution effect, and it was confirmed that there was no problem in operation.

(5) Converter cooling capacity and iron content For each of the test time and the normal time, the converter cooling capacity,
The iron yield was compared between a conventional example, a comparative example, and Examples 1 to 3. The results are summarized in Table 7.

[0046]

[Table 7]

The converter cooling capacity when scrap car scrap was used at 25 cars / ch increased by 6.947% as compared with the conventional example not using scrap car scrap. The heat source increased by the combustion has an effect of dissolving more iron than in the normal operation, and is considered to have contributed to the improvement of 0.301% of the iron yield.

[0048]

As described above, according to the method for producing low alloy steel using scrap car scrap according to the present invention, the following effects can be obtained.

(1) A plurality of presses of a scrapped vehicle having a liquid portion removed in advance and having a sealed portion opened without dismantling,
Press at the same time as lightweight scrap and press to match the shape of scrap chute.
It is possible to use up to about 25 cars / ch.

(2) The special steel component in the discarded vehicle, when 25 vehicles were used in a 250 ton converter, the amount of alloy addition of low alloy steel was about 33%.
%, And low alloy steel can be produced at low cost.

(3) No environmental trouble due to the burning of rubber and resin components in the waste vehicle occurs due to the dilution effect. In addition, a significant increase in the heat source due to these combustions improves the cooling capacity of the converter and contributes to an increase in the yield of iron, which is advantageous not only in low alloy steel but also in smelting ordinary steel.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing how a chute is packed when loading scrap into a converter. FIG. 1 (a) is a front view, and FIG.
(b) is a top view.

FIG. 2 is a conceptual diagram when loading scrap into a converter.

[Explanation of symbols]

 Reference Signs List 1 chute 2 scrap car scrap 3 converter 4 light weight scrap 5 cold pig 6 heavy scrap

Claims (1)

[Claims] At least two scraps obtained by subjecting a steelmaking melting furnace to press-forming after at least taking out only liquid from a substantially original disposal vehicle and taking safety measures such as preventing explosion at the time of charging the furnace are subjected to press molding. A method for producing low-alloy steel using scrap car scrap, characterized in that low-alloy steel is manufactured at low cost by using special steel components in the scrap car scrap by charging as scraps.