JP2012006771A - Wet classification equipment for steel slag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide equipment which when steel slag is crushed and sized, efficiently removes and classifies fine powder sticking to a steel slag surface.SOLUTION: Wet classification equipment for steel slag includes wet sieves 14, 16 for classifying crushed and sized steel slag and a wet cyclone 18 for centrifugally separating particles having a smaller particle size and a smaller specific gravity than undersize particles through the wet sieves 14, 16 from the sieved particles. Since fine powder sticking to a steel slag surface is efficiently classified with the wet sieves and the wet cyclone, it is not necessary to carry out sieving again. Iron-containing steel slag can be subjected to efficient classification and separation into slag and iron.

Description

  TECHNICAL FIELD The present invention relates to an equipment for classifying steel slag such as blast furnace slag and steelmaking slag in a wet manner, and particularly to a wet classification equipment capable of effectively utilizing slow-cooled slag in blast furnace slag and desulfurization slag in steelmaking slag. It is.

  Processing of blast furnace slag and steelmaking slag among steel slag generated at steelworks will be described below.

  The blast furnace slag is classified into a granulated slag rapidly cooled with a large amount of water and a gradually cooled slow slag discharged from the blast furnace. Of these, granulated slag is effectively used as a raw material for cement, while gradual slag is effectively used as roadbed material for roads, etc. due to the formation of strong massive slow-cooled slag due to the inherent hydraulic properties of slag. ing. Moreover, since slow cooling slag has the property equivalent to a natural stone, it is effectively used also as an aggregate for concrete.

On the other hand, steelmaking slag is classified into desulfurization slag, dephosphorization slag, decarburization slag, etc. generated when pre-treatment such as desiliconization, desulfurization, dephosphorization, decarburization is performed on the hot metal discharged from the blast furnace. . These steelmaking slags are effectively used as roadbed materials. In addition, since it contains a lot of CaO and SiO _2, it is also reused in the steelworks.

  By the way, among the blast furnace slag, as shown in FIG. 3A, for example, the slow-cooled slag A is processed in the crushing and sizing plant 1, and the particle size is less than 40 mm, 20 mm or more, less than 20 mm, 5.0 mm or more, Sorted to less than 5.0mm. And the powder with a particle size of less than 5.0 mm is sieved by a sieve 2 outside the system of the crushing and sizing plant 1 into a particle size of less than 5.0 mm and 2.5 mm or more and less than 2.5 mm. Moreover, as shown in FIG.3 (b), operation of a crushing and sizing plant may be changed, and crushing may be repeated and it may be sized to less than 27 mm.

  Of the above, the rock wool (heat insulating material) material having a particle size of less than 40 mm and 20 mm or more, as described in FIG. 3A, and the coarse particle material for concrete having a particle size of less than 20 mm and 5.0 mm or more are used. As a result, the aggregates having a particle size of less than 5.0 mm and 2.5 mm or more are reused as aggregates for concrete blocks, and those having a particle size of less than 2.5 mm are reused as raw materials for cement. Moreover, the thing with a particle size of less than 27 mm demonstrated in FIG.3 (b) is reused as a roadbed material. Hereinafter, the concrete aggregate, concrete block aggregate, and cement raw material are collectively referred to as concrete aggregate.

  However, among these, especially those with a particle size of less than 20 mm and 5.0 mm or more, the fine powder adhering to the surface of the slag during indoor or outdoor storage is piled up due to vibration, contact between slags, etc. The specific gravity, composition, etc. are biased, the slag particle size distribution changes and deviates from the specified particle size distribution, and the quality of the coarse aggregate for concrete deteriorates. Therefore, the sieving is carried out again to remove the fine powder. However, it is difficult to effectively remove the fine powder adhering to the surface with the conventional dry sieve.

  In addition, among the steelmaking slag, the desulfurization slag B generated in the desulfurization process performed as the hot metal pretreatment includes a large amount of iron and a large amount of fine carbon powder. In addition, there are concerns about environmental pollution such as dust scattering.

  Therefore, as shown in FIG. 4, water is poured into the desulfurized slag B, cooled, and stirred indoors, then drained into the water pit 3, exposed to the outside air, and naturally dried (hereinafter referred to as air drying). Then, sieving is performed in the crushing and sizing plant 1 shown in FIG. After sieving, iron is separated from desulfurized slag using a magnetic separator, etc., and the slag is reused in the steelworks and the iron is reused as an iron raw material. Moreover, since the selected iron content is granular iron with few impurities and uniform particle size, it can be sold as a high-quality iron raw material.

  However, desulfurized slag with a high sulfur content is air-dried after submerging and sifted in a state where the surface is dried, so that powdered slag with a high sulfur content is fixed to the recovered iron content. Low quality as a source.

  Therefore, for example, in Patent Document 1, the steel-containing slag particles that have been crushed and sized to 1 to 5 mm with a pulverizer after cooling are added to and mixed with the carbon-containing recovered particles and the iron-containing recovered particles using a mixer. It is described that it is used as a part of a raw material for sintered ore.

  Moreover, in patent document 1, the iron content contained in the steelmaking slag screened and removed by the magnetic separator during the pulverization is sieved to 5 mm or less with a sieve to obtain iron-containing recovered particles, and those exceeding 5 mm are rolled. It is also described that it is used as a part of steelmaking raw materials such as a furnace iron source and a converter coolant.

  However, when desulfurized slag is the target, the slag and iron content are not sufficiently separated, so when the recovered iron content is put into the molten steel, the sulfur content in the steel increases, leading to a decrease in quality. There is no change.

JP 2001-192741 A

  The problems to be solved by the present invention when classifying steel slag are the following two points. The first is that it is difficult to effectively remove fine powder adhering to the surface when gradual slag is crushed and sized as concrete aggregate, so that the fine powder segregates during storage and the particle size distribution changes. It is out of the specified particle size distribution and the quality of the aggregate for concrete deteriorates. Second, since desulfurized slag has a high sulfur content in the slag, a high sulfur content slag adheres to the surface of the recovered iron and the quality as an iron source is low.

  The present invention solves the above-mentioned problems of the prior art when effectively classifying and effectively using steel slag such as blast furnace slag and steelmaking slag.

That is, the steel slag wet classification equipment of the present invention does not change the particle size distribution of the aggregate for concrete during storage due to segregation of fine powder, and the sulfur content of the desulfurized slag is high on the recovered iron surface. To prevent the sticking
Wet sieve for sieving steel slag that has been crushed and squeezed or treated with water into a predetermined particle size, and a wet type for centrifuging a material having a particle size smaller than the sieved material and having a smaller specific gravity from the sieve under the wet sieve Having a cyclone is the main feature.

  The steel slag wet classification equipment of the present invention screens steel slag into a predetermined particle size with a wet sieve, so in the case of blast furnace slow-cooled slag, fine powder adhering to the surface of the crushed and sized concrete aggregate Removal is possible and there is no need to screen again. In addition, since desulfurized slag contains a large amount of granular iron, it is possible to accurately separate iron and slag by sieving the desulfurized slag with a wet sieve. Moreover, it can suppress that powdery slag with a high sulfur content adheres to the surface of the iron content collect | recovered from desulfurization slag, and the effective utilization as a high quality iron source comes to be achieved while improving the recovery rate of iron content.

  In the steel slag wet classification equipment of the present invention, in the case of a blast furnace slow-cooled slag in which the steel slag is crushed and sized, a magnetic separator is provided upstream of the wet sieve, It is desirable to sort out bullion.

  Moreover, in the steel slag wet classification equipment of the present invention, in the case of desulfurized slag in which the steel slag is injected, it is possible to separate the iron and slag accurately by sieving the desulfurized slag with a wet sieve as described above. Yes, a magnetic separator may be used.

  In the present invention, since the steel slag is sieved to a predetermined particle size by a wet sieve, fine powder adhering to the surface of the coarse aggregate for concrete can be removed in the case of a blast furnace slow-cooled slag. Therefore, even when stored for a long period of time, it does not deviate from the specified particle size distribution range.

  For the same reason, in the case of desulfurization slag, since it is treated with a wet sieve without being air-dried after submersion, it is possible to suppress the adhesion of high sulfur content slag to the surface of the recovered iron content. Can be separated and recovered efficiently. In addition, because of wet processing, scattering of fine carbon powder and the like can be suppressed.

It is a figure explaining an example of the wet classification equipment of this invention in case the steel slag is a blast furnace slow cooling slag. It is a figure explaining an example of the wet classification equipment of this invention in case the steel slag is desulfurization slag. It is a figure explaining an example of the classification equipment of the conventional blast furnace slow cooling slag, (a), when classifying into a thing with a particle size of less than 40 mm 20 mm or more, less than 20 mm 5.0 mm or more, and less than 5.0 mm, (b) Is a case where pulverization is repeated and the particle size is reduced to less than 27 mm. It is a figure explaining an example of the classification equipment of the conventional desulfurization slag.

  In the blast furnace slow-cooled slag, the fine powder adhering to the slag crushed in the pulverization and sizing plant is efficiently removed, and the particle size distribution does not change during the pile storage. The purpose of preventing desulfurization slag having a high sulfur content from adhering to the surface of the steel was achieved by sieving the steel slag into a predetermined particle size with a wet sieve.

Hereinafter, the steel slag wet classification equipment of the present invention will be described.
First, an example of wet classification equipment for blast furnace slow cooling slag of the present invention will be described with reference to FIG.

  A is a slow-cooled slag obtained by gradually cooling the molten slag discharged from the blast furnace into a lump, and is processed in the crushing and sizing plant 1 so that the particle size is, for example, less than 40 mm and less than 20 mm and less than 20 mm. The Of these, those having a particle size of less than 40 mm and 20 mm or more are reused as a material for rock wool (heat insulating material). On the other hand, in the present invention, those having a particle size of less than 20 mm are sent from the receiving hopper 11 to the magnetic separator 13 via the belt conveyor 12 and sorted into the magnetically-adhered material Aa containing iron and the others.

  In addition, it is the same as before that the operation of the crushing and sizing plant may be changed and the crushing may be repeated to reduce the particle size to less than 27 mm in order to be reused as the material for the roadbed material.

  What the magnetic deposit Aa has been removed by the magnetic separator 13 is sent to the primary separation wet sieve 14 by the belt conveyor 12, where water w is dispersed, and the particle size is, for example, less than 20 mm, 15 mm or more, less than 15 mm, 5.0 mm or more, Sift into 3 pieces of less than 5.0mm and 2.5mm or more. All of these sieved materials are reused as aggregates for concrete.

  On the other hand, those having a particle size of less than 2.5 mm under the sieve are sent to the secondary separation wet sieve 16 via the primary classification tank 15, where the particle size is, for example, less than 2.5 mm and 0.8 mm or more. And sieve to less than 0.8mm.

  Those having a particle size of less than 0.8 mm under the sieve are sent to the wet cyclone 18 via the secondary classification tank 17, where the particle size is less than 0.8 mm and 0.075 mm or more, and 0.075 mm. Centrifuge to less than.

  Those having a particle size of less than 0.8 mm and 0.075 mm or more are sent again to the secondary separation wet sieve 16 and sieved together with those having a particle size of less than 2.5 mm and 0.8 mm or more. And a thing with a particle size of less than 2.5 mm and 0.075 mm or more is reused as a material for fine aggregate for concrete. Those having a particle size of less than 0.075 mm are sent to a slurry tank 19 where a coagulating precipitant is added for aggregation and precipitation, followed by dehydration filtration with a compressed filter press 20. Those having a particle size of less than 0.075 mm are reused as cement raw materials.

  In the wet classification equipment of the present invention having the above-described configuration, the slow-cooled slag A crushed and sized in the pulverization and sizing plant 1 is finely removed with water when sieving with the primary separation wet sieve 14, so that Does not have fine powder attached and does not need to be sieved again. Moreover, even when these sieved products are stored in a pile for a long time, they do not deviate from the specified particle size distribution range.

  When sorting the iron contained in the slowly cooled slag A, it is desirable to place and sort the magnetic separator 13 before sieving with the primary separation wet sieve 14 as in the above configuration.

Next, an example of the desulfurization slag wet classification equipment of the present invention will be described with reference to FIG.
B is desulfurization slag, and is injected into the water pit 3 after water injection, cooling, and indoor stirring to prevent the scattering of fine carbon powder.

  In the present invention, the desulfurized slag in the water pit 3 is put into the vibration feeder 21 and supplied to the wet vibration sieve 22 through the vibration feeder 21 to sprinkle water while sprinkling water. Sift into pieces.

  The desulfurized slag under the sieve is sent to the primary separation wet sieve 14 through the mixing tank 23, and after spraying water to remove the powdered desulfurized slag adhering to the surface, the base metal Bb and the powdered slag are removed. Sift into pieces. In the example of FIG. 2, the bare metal Bb is sieved to, for example, a particle size of less than 30 mm, 15 mm or more, less than 15 mm, 5 mm or more, and less than 5.0 mm, 2.5 mm or more.

  Since the above-mentioned bullion Ba and Bb have little powdery desulfurization slag adhering to the surface, the sulfur content becomes low and can be effectively used as a steelmaking raw material.

  On the other hand, the desulfurized slag Bc having a particle size of less than 2.5 mm under the sieve is sent to the secondary separation wet sieve 16 through the primary classification tank 15, where the particle size is, for example, less than 2.5 mm and 0.8 mm or more. Sieving into one with less than 0.8mm.

  Those having a particle size of less than 0.8 mm under the sieve are sent to the wet cyclone 18 through the secondary classification tank 17, where the particle size is 0.8 to 0.075 mm and less than 0.075 mm. Centrifuge into one.

  Those having a particle size of less than 0.8 mm and 0.075 mm or more are sent again to the secondary separation wet sieve 16 and sieved together with those having a particle size of less than 2.5 mm and 0.8 mm or more. And a thing with a particle size of less than 2.5mm and 0.075mm or more is collect | recovered as sandy slag, and is reused as an iron-making raw material. Those having a particle size of less than 0.075 mm are sent to a slurry tank 19 where a coagulating precipitant is added for aggregation and precipitation, followed by dehydration filtration with a compressed filter press 20. When the particle size is less than 0.075 mm, the dehydrated cake is recovered and reused as an ironmaking raw material.

  In the wet classification equipment of the present invention having the above-described configuration, the metal contained in the desulfurization slag B is separated from the desulfurization slag B by the wet vibrating sieve 22 and the primary separation wet sieve 14 without using a magnetic separator. Accordingly, the amount of desulfurized slag attached to the surface of the metal bars Ba and Bb is small, and the sulfur content of the metal bars Ba and Bb is reduced, so that it can be effectively used as a steelmaking raw material.

  The present invention is not limited to the above example, and it goes without saying that the embodiments may be changed as appropriate within the scope of the technical idea described in each claim.

  For example, in the example of FIG. 1, two wet sieves for sieving steel slag, the primary separation wet sieve 14 and the secondary separation wet sieve 16, are installed, but one wet sieve may be used.

1 Crushing and Sizing Plant 3 Water Pit 13 Magnetic Separator 14 Primary Separation Wet Sieve 16 Secondary Separation Wet Sieve 18 Wet Cyclone 22 Wet Vibrating Sieve A Slow Cooling Slag B Desulfurization Slag

Claims (3)

A wet sieve that screens steel slag that has been crushed and sized or irrigated with water to a predetermined particle size;
A wet classifier for steel slag, characterized by having a wet cyclone for centrifuging a material having a particle size smaller than that of the sieved material and having a specific gravity smaller than that of the sieved product.   The steel slag is a blast furnace slow-cooled slag in which the steel slag is crushed and sized, and a magnetic separator is provided upstream of the wet sieve to select and remove the metal in the blast furnace slow-cooled slag before being put into the wet sieve. The steel slag wet classification equipment according to claim 1.   The steel slag wet classification equipment according to claim 1, wherein the steel slag is desulfurized slag subjected to water injection treatment, and the metal slag is separated with the wet sieve.

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