JPH10314799A - How to treat oily sludge with high iron content - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove oil from oil bearing sludge having high iron content which is produced at an iron mill by a simple process to utilize the oil as a raw material for sinter. SOLUTION: Oil bearing sludge 2 having high iron content is dried at a solar evaporation area and spread over a discharge yard 12, and converter slag 9 of high temperature discharged from a steel converter 11 is discharged onto the sludge 2 to bring it into contact with the sludge so that the oil of the sludge 2 can be removed by burning it. The sludge having a high iron content and free from oil is utilized as a raw material for sinter, which is fed into a blast furnace as sintering ores to recover iron, while the slag discharged from the blast furnace is utilized as granulated slag.

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 various oil-containing sludges containing a large amount of iron generated in a lump mill, a rolling mill or a steel mill in an ironworks.

[0002]

2. Description of the Related Art In an ironworks, an oil component caused by grease such as sludge generated from a lump mill or a rolling mill, and sludge generated in a direct cooling system of a slab in a continuous casting facility installed in a steel mill. Containing 2 to 25%. Such sludge is generally used as follows in order to recycle oil-containing sludge as a raw material for iron production because of its high iron content.

(1) In many cases, sinter is recycled as a raw material, but the oil is volatilized in the sintering machine and accumulates in the dust collecting device, and spontaneously ignites in a high-temperature atmosphere, causing the dust collecting device to be burned out. Cause. Because of this, oil has recently been
The sludge is limited to an extremely low oil content of less than 10%, and among the sludges mentioned above, a high oil content sludge containing an oil content of 10 to 25% by weight cannot be reused as a sintering raw material.

(2) In some cases, the oil content in the oil-containing sludge is incinerated, reduced by granulation, and charged as pellets in a blast furnace.
The construction and operation of the equipment for this purpose not only requires a great deal of cost, but also has the drawback of causing environmental problems including air pollution accompanying combustion. (3) After briquetting the oil-containing sludge, sintering it at a high temperature and charging it into a blast furnace or converter, or charging briquettes molded by a briquetter molding machine directly into a converter. is there. In these cases, when the briquette is handled, it is apt to be broken and powdered, resulting in a loss due to a decrease in yield. In particular, since oil causes a reduction in the crushing strength of briquettes, oil incineration is required, and the same problem as in the case (2) occurs.

(4) The oil-containing sludge is dehydrated to a water content of 20 to 40% by weight, cultivated and dried, then a cement-based binder is added, and the mixture is subjected to humidity control, kneading and granulation to produce non-dried cured pellets. Used as steelmaking pellets (Japanese Patent Publication No. 57-4)
No. 3622), the equipment is relatively simple, but the equipment and operating costs are still not cheap and problems remain.

FIG. 2 shows a case in which a conventional oil-containing sludge having a high oil content is naturally dried, and sinter or pellets are produced by a sintering facility or a pellet facility, and are used as an iron source of a blast furnace. As shown in FIG. 2, oil-containing sludge is mixed with water in a sludge collecting tank 1 such as a scale pit or a sedimentation tank.
The oil-containing sludge 2 which has settled in the sludge collecting tank 1 and separated from water and deposited in the tank is usually carried out to the ground hopper 4 using the bucket 3 or the like and temporarily stored. Then, the oil-containing sludge 2 cut out from the ground hopper 4 is carried out by a dump truck 5 or carried out in a fluidized state by a lorry truck 6 and stored in a storage pond 8 excavated at a predetermined place to perform simple dewatering. . Later, using the shovel car 13, the oil-containing sludge 2 in the reservoir 8 is scraped out,
It is transported to the sun drying station 7 and piled up, and naturally dried by solar heat for a long time.

After being sufficiently air-dried, the oil in the oil-containing sludge 2 is removed by burning in an oil incineration plant, supplied to the sintering plant as a sintering raw material, and mixed with other sintering raw material for sintering. The sinter is produced by the treatment, or supplied to a pellet facility, mixed with other raw materials, and reduced to produce pellets. Then, the sintered ore or the pellet is reused as a raw material for the blast furnace. In this case, fuel and transportation costs are required to burn the oil in the incinerator to remove the oil, and equipment costs for installing a cooling fan and the like for cooling after the combustion are required. It is expensive and costly. When reused as raw materials for sintering and pellets, these facilities are usually already provided, so most of the facilities do not need to be newly installed except for the necessary hoppers, etc., but the operating cost increases. And the problem of cost remains overall.

[0008]

The oil sludge content of the sewage sludge of a lump mill or rolling mill at a steel mill or the sewage sludge of a direct cooling water system of a continuous casting facility is as high as 10 to 25% by weight. Despite containing 25 to 40% by weight of iron, it could not be sufficiently recycled as a raw material for iron making, and an inexpensive treatment method was required.

Due to the circumstances described above, the reuse of oil-containing sludge containing a large amount of iron has a problem contrary to its value as an iron resource, and it is rather cheaper to dispose of it as landfill by paying a dumping fee as industrial waste. It may be. However, also here, there are restrictions such as “oil content of 5% or less” and restrictions such as prohibition of dilution by mixing with other wastes, and the fact is that sludge with high oil content cannot be dumped and there is no place to go. Was.

In view of the above, the present invention recycles oil-containing sludge containing a large amount of iron, which is difficult to dispose of, as a raw material for blast furnaces by simple treatment, and uses molten slag discharged from the blast furnace as an iron source. It is an object of the present invention to provide a method for treating oil-containing sludge containing a large amount of iron used as granulated slag or the like.

[0011]

According to a first aspect of the present invention, there is provided a method for treating oil-rich sludge containing a large amount of iron, the method comprising the steps of: Of the oil-containing sludge is removed by combustion to form a sludge rich in iron, which is blended with other sintering raw materials and charged into a blast furnace as a sintered ore. This is a method for treating oil-containing sludge containing a large amount of iron.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG.
Is collected together with water in a sludge collecting tank 1 such as a scale pit or a sedimentation tank. As shown in Table 1, the rolling ring water sludge generated from the plate water, hot rolling, and ring water of the steel mill has a high iron content and a low oil content. On the other hand, the sludge ring water sludge of the lump factory has low iron content and high oil content. In addition, the continuous casting ring water sludge of the direct cooling water system from the continuous casting plant has both iron and oil components between them.

[0013]

[Table 1]

The oil-containing sludge 2 having such components is precipitated in the sludge collecting tank 1, and the oil-containing sludge 2 separated from the water 14 is stored in the storage pond 8 through the same procedure as described with reference to FIG. To remove water to some extent by infiltration into the ground and solar heat. Thereafter, the shovel car 13 is operated to scrape out the oil-containing sludge 2 in the reservoir 8, move to the sun drying station 7, and pile up. Piled oil impregnated sludge 2
Is naturally dried by solar heat slowly and naturally, except that the tilling work, which is occasionally inverted, is periodically performed. If such a low-temperature drying operation is performed in a large greenhouse, the drying can be performed more efficiently, and the fluctuation of the degree of drying can be reduced because it is not affected by rainy weather. Usually, the oil-impregnated sludge 2 deposited in the solar drying area 7 is often naturally dried by the sun over a long period of about one year while being exposed to rain, so that the oil-impregnated sludge 2 is dried. be able to.

On the other hand, the converter 11 is tilted to the tapping side to discharge molten steel in the furnace from the tapping port 15, while the converter 11 is tilted to the opposite waste side to convert the converter slag in the furnace. 9 is discharged through a furnace opening into a pan 10 mounted on a truck on the track, and then discharged into a special discharge yard 12
And then discharged from the pot 10 to the ground or a dedicated container. At this time, most of the converter slag 9 is still in a molten and fluid state, but rapidly cools and solidifies as it is discharged, and enters a cooled state. At this time, water may be sprinkled in order to promote the cooling of the converter slag 9, but in any case, in the past, only cooling was performed without effectively utilizing the latent heat and sensible heat possessed by the converter slag. .

According to the present invention, a converter slag in a molten state having a latent heat or a sensible heat, a semi-molten state or a solid state immediately after solidification (hereinafter referred to as a converter slag in a high temperature state) is contacted with oil-containing sludge containing a large amount of iron. The oil is removed by combustion. There are many possible means for bringing the converter slag and the oil-containing sludge into contact with each other. Here, some specific examples will be described.

(1) The oil-impregnated sludge 2 dried in the sun drying station 7 as described above is previously laid on the ground of the discharge yard 12, and the oil sludge 2 in the pot 10 discharged from the converter 11 is placed thereon. The furnace slag 9 is discharged and brought into contact, and the sun-dried oil-containing sludge 2 is heated by effectively utilizing the latent heat and sensible heat of the converter slag in a high temperature state, and is removed by burning oil. (2) The oil-impregnated sludge 2 previously dried in the sun is put in the pot 10, the molten converter slag 9 discharged from the converter 11 is received and brought into contact therewith, and the temperature is raised to burn the oil. Remove. When the converter slag 9 is received on the oil-containing sludge 2 in the pot 10, a steam explosion is prevented from occurring.
It is indispensable to completely remove the moisture of the sun-dried oil-containing sludge 2 by utilizing residual heat or the like. In addition, since smoke and flame are often generated during the burning process of the oil, it is necessary to consider installation of dust collecting equipment.

(3) The sun-dried oil-containing sludge 2 is put into contact with the converter slag 9 in the molten state received from the converter 11 into the pot 10 and brought into contact therewith, and is removed by burning oil. (4) On the converter slag 9 in the molten state, semi-molten state or solid state immediately after solidification discharged from the pot 10 onto the discharge yard 12,
Sun-dried oil-containing sludge 2 is sprayed and brought into contact with a projector or other equipment, the temperature is raised, and the oil is removed by combustion. In this case, the oil content of the oil-containing sludge 2 is completely evaporated and removed by the first contact with the spraying, and then the converter slag 9 is re-discharged thereon next time, whereby the burning and removal of the oil can be surely performed.

(5) An unusual case is that the oily slag 9 which is not dried at all and has a high moisture content is placed on the converter slag 9 in a molten state, a semi-molten state or a solid state immediately after solidification, which is discharged onto the ground of the discharge yard 12. The sludge 2 is sprayed and brought into contact.
Since this is performed also for the purpose of cooling the temperature of the converter slag 9 by water sprinkling, the temperature of the converter slag 9 is reduced, so that the oil content in the oil-containing sludge 2 is not easily burned by one contact. . Therefore, after the water in the oil-containing sludge 2 is evaporated by the heat of the converter slag 9 in the first contact, the high-temperature converter slag 9 is discharged again onto the oil-containing sludge 2 from which the water has been removed, The oil-containing sludge 2 is heated and removed by burning oil. The advantage in this case is that the labor for drying the oil-containing sludge 2 in advance in the sun can be omitted, and fluid conveyance means such as pumping directly from the sludge pit can be adopted.
Distribution costs can be reduced.

As described above, by contacting the sun-dried oil-containing sludge or the oil-containing sludge which is not dried at all and has a high moisture content with the converter slag in a high temperature state, the oil-containing sludge from which the oil component has been burned off is It is mixed with converter slag. By the way, converter slag is
At a steel mill, about 130 kg is generated per ton of crude steel. Recently, all of these have been used as a part of sintering raw materials and have been charged into blast furnaces as sinter. On the other hand, the amount of oil-containing sludge generated is on the order of 1/100 or less of the amount of converter slag generated, so it is only a small amount as a whole. It does not have the effect of causing component fluctuation.

Further, since oil is removed by the combustion caused by the contact between the oil-containing sludge and the converter slag, there is no need to worry about a fire caused by the oil in the exhaust gas collection system of the sintering machine. In this way, the sludge rich in iron from which oil has been removed is blended with other sintering raw materials, sintered and charged into a blast furnace as a sintered ore, thereby achieving effective resource recovery of iron. . Here, other components of the sludge other than iron are discharged from the blast furnace as part of blast furnace slag generated at a rate of about 300 kg per ton of hot metal. This blast furnace slag is used as granulated slag or slowly cooled slag as a raw material for cement,
All can be used as roadbed materials and the like.

In some cases, valuable iron in the converter slag is recovered by magnetic separation before the converter slag discharged from the converter is cooled and used as a raw material for sintering. In this case, part or all of the converter slag will not be charged into the blast furnace, but valuable iron in the converter slag collected by magnetic separation, etc. will be reused by recycling it to the converter, etc. However, there is no difference in using it as an iron source.

[0023]

EXAMPLE Among the oil-containing sludges containing oil components shown in the above Table 1, continuously cast ring water sludge was deposited in the sun drying plant 7 through the process shown in FIG. 1, and was exposed to rain for about one year. Was naturally dried over the sun over a long period of time. The dried oil-containing sludge 2 is dug out from the sun drying station 7, transported to the discharge yard 12, and laid in advance. And on the oil-impregnated sludge that has been pre-paved on the ground of the discharge yard,
The converter slag in the molten state having the components shown in Table 2 is discharged from the converter 11 into the pot 10 and brought into contact therewith, and the latent heat and sensible heat held by the converter slag in the high-temperature state are effectively used for solar radiation. The oil content of the dried oil-containing sludge 2 is removed by combustion.

[0024]

[Table 2]

Since the amount of converter slag discharged from the converter is much larger than the amount of continuous cast ring water sludge generated, the oil content of the oil-containing sludge could be almost completely removed by combustion. The continuously cast ring water sludge from which the oil was removed in this manner was blended into a sintering raw material and charged into a sintering machine to produce a sinter. When the obtained sinter was used as a raw material for a blast furnace, the blast furnace operation could be performed under favorable furnace conditions, and the hot metal of the target component could be produced. Also, granulated slag was manufactured from blast furnace slag discharged from the blast furnace,
Other components other than iron in the oil-containing sludge also migrated to the granulated slag and could be used effectively.

[0026]

As described above, according to the present invention, the oil-containing sludge is easily removed by combustion by bringing the oil-containing sludge having a high iron content into contact with the high-temperature converter slag discharged from the converter. Is used as part of the sintering raw material without affecting the operation of the sintering machine,
Recycled as sinter in the blast furnace. For this reason, the iron content in the oil-containing sludge is recovered in the hot metal discharged from the blast furnace,
The slag discharged together with the hot metal can be used as granulated slag or the like. On the other hand, the latent heat and sensible heat of converter slag, which have not been effectively used in the past, can be used for drying and burning oil-containing sludge, and are also valuable in the effective use of waste heat.

As a result, it becomes possible to recycle oil-containing sludge as a resource which has not been economically treated in terms of cost, and has a great industrial effect.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a treatment process of an oil-containing sludge according to the present invention.

FIG. 2 is a schematic explanatory view showing a conventional oil-containing sludge treatment process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sludge collection tank 2 Oil impregnated sludge 3 Bucket 4 Ground hopper 5 Dump truck 6 Lorry truck 7 Solar drying station 8 Reservoir 9 Converter slag 10 Pot 11 Converter 12 Discharge yard 13 Shovel car 14 Water 15 Steel tap

Claims (1)

[Claims] 1. A method for treating oil-rich oil-containing sludge, wherein the oil-rich oil-containing sludge is brought into contact with a high-temperature converter slag discharged from a converter, and the oil content in the oil-containing sludge is removed by combustion. A method of treating oil-containing sludge containing a large amount of iron, wherein the sludge is rich in iron, and the resulting mixture is mixed with other sintering raw materials and sintered ore is charged into a blast furnace.