JP2006063375A - Method for manufacturing raw material to be sintered - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a raw material to be sintered, which improves the productivity of a drum mixer, when making a limestone-based raw powder and a solid-fuel-based raw powder adhere to the surface of para-particles containing iron ore and a SiO<SB>2</SB>-containing raw material. <P>SOLUTION: The manufacturing method comprises: charging the iron ore and the SiO<SB>2</SB>-containing raw material from a charging hole of a drum mixer and granulating them; simultaneously adding the limestone-based raw powder with an average particle diameter of 250 μm to 1 mm and the solid-fuel-based raw powder with an average particle diameter of 250 μm to 1 mm into such a region set at some midpoint of a downstream that the para-particles granulated in the drum mixer stay therein for further 10 to 50 seconds before arriving at the exhaust port of the drum mixer; and making the limestone-based raw powder and the solid-fuel-based raw powder adhere to the surface of the para-particles before they arrive at the exhaust port. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a raw material for sintering used when producing sintered ore using a downward suction droidoid type sintering machine.

  The sintered ore charged into the blast furnace is generally manufactured through the following treatment.

First, raw materials roughly classified into the following (a) to (d) are charged into a drum mixer, and an appropriate amount of water is added and mixed and granulated to produce a granular sintering raw material.
(a) Iron ore
(b) SiO ₂ -containing material consisting of silica, serpentine, nickel slag, etc.
(c) Limestone powder raw material containing CaO such as limestone
(d) Solid fuel-based powder raw material used as a heat source for powdered coke, anthracite, etc. The raw material for sintering consisting of granulated particles obtained by mixing and granulating these materials (a) to (d) It is stacked in layers so as to have a predetermined thickness (for example, 500 to 700 mm) on the pallet of the binding machine. Next, the solid fuel powder material distributed in the upper part of the sintering raw material layer loaded on the pallet is ignited, and after ignition, the solid fuel powder material is burned while sucking air downward. The raw material for sintering is sintered with combustion heat to form a sintered cake. At that time, hematite contained in iron ore reacts with CaO contained in limestone powder raw material and iron ore to produce calcium ferrite melt (hereinafter referred to as CF melt), and the CF melt is used for sintering. Contributes to the combination of raw materials. The sintered cake is crushed and sized to obtain a sintered ore having a predetermined particle size. On the other hand, the sintered ore that does not satisfy the predetermined particle size is returned to ore and reused as a sintering raw material.

  When the sintering raw material is sintered, the CF melt is selectively produced on the surface of the sintering raw material, and if the function of the CF melt is utilized, the sintered ore can be produced efficiently. In addition, the amount of various materials used in the raw material for sintering can be reduced. Therefore, various techniques for selectively generating the CF melt on the surface of the raw material for sintering have been studied.

For example, in Patent Document 1, (a) iron ore and (b) SiO ₂ -containing raw material are charged from a drum mixer inlet and granulated, and the granulated particles (hereinafter referred to as pseudo particles) A technique is disclosed in which (c) a limestone powder material and (d) a solid fuel powder material are added at a position where the residence time until reaching the discharge port is 10 to 90 seconds. In the raw material for sintering obtained by this technique, the limestone powder raw material and the solid fuel powder raw material are attached to the surface of the pseudo particles of the iron ore and the SiO ₂ -containing raw material. Therefore, when the sintering raw material is sintered, a CF melt is selectively generated on the surface of the sintering raw material.

However, in the technique disclosed in Patent Document 1, after adding the limestone powder raw material and the solid fuel powder raw material to the pseudo particles, the sintering raw material is discharged from the drum mixer after a maximum of 90 seconds. It takes a long time to manufacture the raw material for sintering. That is, the technique disclosed in Patent Document 1 is an effective technique for selectively generating the CF melt on the surface of the raw material for sintering, but there is room for improvement from the viewpoint of improving the productivity of the drum mixer. It was left.
Japanese Patent Laid-Open No. 2003-138319

The present invention solves the above problems and performs a treatment (hereinafter referred to as an exterior treatment) for adhering the limestone powder raw material and the solid fuel powder raw material to the surface of the pseudo particles of the iron ore and the SiO ₂ -containing raw material. It is an object of the present invention to provide a method for producing a raw material for sintering that can improve the productivity of a drum mixer.

  The inventor has intensively studied a technique for improving the productivity of a drum mixer when performing exterior processing. As a result, it was found that the residence time (hereinafter referred to as exterior time) until the pseudo particles reach the discharge port after adding the limestone powder material and the solid fuel powder material to the pseudo particles in the drum mixer was found. . In other words, if the particle size of the limestone powder raw material and the solid fuel powder raw material added to the pseudo particles in the drum mixer is reduced, it can be easily adhered to the surface of the pseudo particles even if the exterior time is shortened. . If the exterior time is shortened, the productivity of the drum mixer in the exterior processing is improved. The present invention has been made based on these findings.

That is, the present invention relates to a method for producing a raw material for sintering in which a raw material is charged into a drum mixer and granulated as a pretreatment of a process for producing sintered ore using a downward suction droidoid sintering machine. The iron ore and SiO ₂ -containing raw material is charged from the mixer inlet and granulated, and the residence time until the pseudo particles granulated in the drum mixer reach the drum mixer outlet is 10 to 50 Add a limestone powder material with an average particle diameter of 250 μm to 1 mm and a solid fuel powder material with an average particle diameter of 250 μm to 1 mm in the region set in the middle of the downstream side in the range of seconds. This is a method for producing a raw material for sintering in which a raw material and a solid fuel-based powder raw material are adhered to the surface of a pseudo particle.

  In the method for producing a raw material for sintering of the present invention, in the middle of the downstream side, the residence time until the pseudo particles granulated in the drum mixer reach the discharge port of the drum mixer is in the range of 30 to 50 seconds. It is preferable to add a limestone powder material having a particle diameter of 1 mm or less and a solid fuel powder material having a particle diameter of 1 mm or less in the set region. Moreover, it is preferable that a screw conveyor is inserted from the discharge port of the drum mixer, and the limestone powder raw material and the solid fuel powder raw material are dropped from the end of the screw conveyor and added to the pseudo particles.

  According to the present invention, the productivity of the drum mixer in the exterior processing can be improved.

FIG. 1 is a layout diagram schematically showing an example of an apparatus for manufacturing a raw material for sintering by applying the present invention. In the present invention, the iron ore 2 and the SiO ₂ -containing raw material 3 are charged into the drum mixer 1 from the charging port and granulated. The granulated particles (namely, pseudo particles) of the iron ore 2 and the SiO ₂ -containing raw material 3 granulated in the drum mixer 1 move to the discharge port.

  The limestone powder raw material 4 and the solid fuel powder raw material 5 are added in the region set in the middle of the downstream side where the residence time (that is, the exterior time) until the pseudo particles reach the discharge port is in the range of 10 to 50 seconds. To do. The specific method is, for example, adjusting the tip position of a belt conveyor or a screw conveyor arranged so as to be able to advance and retreat in the longitudinal direction in the drum mixer 1 from the downstream discharge port, and limestone powder raw material 4, solid fuel powder By adding the raw material 5, the exterior time can be maintained within a predetermined range. An appropriate amount of water may be added as necessary. As a result, the limestone powder raw material 4 and the solid fuel powder raw material 5 are uniformly coated on the surface of the pseudo particles until the pseudo particles reach the discharge port.

  In order to transport the limestone powder raw material 4 and the solid fuel powder raw material 5 to a position where a predetermined exterior time is secured, a transport device (for example, a belt conveyor, a screw conveyor, etc.) must be inserted into the drum mixer 1. I must. However, since a large amount of dust is floating in the drum mixer 1, when a belt conveyor is used, the failure frequency of the motor and roller for supplying driving force to the belt increases.

  Therefore, it is possible to feed the limestone powder raw material 4 and the solid fuel powder raw material 5 from the outside of the discharge port without inserting a belt conveyor into the drum mixer 1 and increasing the conveying speed. When this method is employed, when the limestone powder raw material 4 and the solid fuel powder raw material 5 are added to the pseudo particles, not only the impact of natural fall but also the horizontal impact is applied due to the conveying speed. Therefore, the pseudo particles are likely to collapse, and the limestone powder raw material 4 and the solid fuel powder raw material 5 are mixed inside the pseudo particles.

  Since the screw conveyor does not need to have a large number of rollers and has a simple structure, even if it is inserted into the drum mixer 1, it is unlikely to break down and can operate stably. If the screw conveyor is inserted into the drum mixer 1, the tip position can be adjusted, and the limestone powder raw material 4 and the solid fuel powder raw material 5 can be added to a predetermined position. In that case, the impact is alleviated (only the impact of natural fall), so that the pseudo particles can be prevented from collapsing. Moreover, collapse of the limestone powder raw material 4 and the solid fuel powder raw material 5 can be prevented, and the particle diameter adjusted in advance can be maintained. Therefore, it is preferable to use a screw conveyor in the present invention.

  The average particle diameters of the limestone powder raw material 4 and the solid fuel powder raw material 5 used for the exterior treatment are both 250 μm to 1 mm. When the average particle size of the limestone powder raw material 4 or the solid fuel powder raw material 5 exceeds 1 mm, coarse particles of the limestone powder raw material 4 or the solid fuel powder raw material 5 increase, so that the surface of the pseudo particle is short. It becomes difficult to coat uniformly over time. On the other hand, when the average particle size is less than 250 μm, the fine particles of the limestone powder raw material 4 and the solid fuel powder raw material 5 increase and intrude through gaps that inevitably exist in the pseudo particles, and also enter the limestone powder. The raw material 4 and the solid fuel-based powder raw material 5 are mixed into the sintering raw material. When such a sintering material is sintered, the effect of selectively generating the CF melt on the surface of the sintering material cannot be obtained.

  If the exterior time is less than 10 seconds, the surface of the pseudo particles cannot be uniformly coated. If the exterior time exceeds 50 seconds, the limestone powder raw material 4 and the solid fuel powder raw material 4 will be granulated again after the limestone powder raw material 4 and the solid fuel powder raw material 5 are added. 5 is mixed inside the pseudo particle. As a result, not only the surface of the pseudo particles cannot be uniformly coated, but also the sintering raw material in which the limestone powder raw material 4 and the solid fuel powder raw material 5 are mixed. Therefore, the exterior time needs to satisfy the range of 10 to 50 seconds. However, in order to prevent peeling of the limestone powder raw material 4 and the solid fuel powder raw material 5 covering the surface of the pseudo particles, the exterior time is preferably set to 30 seconds or more.

  Thus, the productivity of the drum mixer can be improved by shortening the exterior time in the exterior processing. Moreover, when the obtained raw material for sintering is sintered, the CF melt is selectively generated on the surface of the raw material for sintering, and the sintered ore can be efficiently manufactured.

As shown in FIG. 1, the iron ore 2 and the SiO ₂ -containing raw material 3 were charged into the drum mixer 1 from the charging port and granulated. In addition, silica stone or nickel slag was used as the SiO ₂ -containing raw material 3. In the drum mixer 1, the iron ore 2 and the SiO ₂ -containing raw material 3 are granulated into pseudo particles, and the residence time until the pseudo particles reach the discharge port of the drum mixer 1 is 40 seconds. Limestone with an average particle size of 0.9 mm was added as the powder raw material 4 and powder coke with an average particle size of 0.9 mm was added as the solid fuel-based powder raw material 5. The specific method is that the residence time until the pseudo particles reach the discharge port is 40 seconds by adjusting the tip position of the screw conveyor disposed so as to be able to advance and retreat in the longitudinal direction in the drum mixer 1 from the discharge port. Limestone powder material 4 and solid fuel powder material 5 were added to the position. Therefore, the exterior time is 40 seconds. This is an invention example.

On the other hand, as Comparative Example 1, as shown in FIG. 1, the iron ore 2 and the SiO ₂ -containing raw material 3 were charged into the drum mixer 1 from the charging port and granulated. In addition, silica stone or nickel slag was used as the SiO ₂ -containing raw material 3. In the drum mixer 1, the iron ore 2 and the SiO ₂ -containing raw material 3 are granulated into pseudo particles, and the residence time until the pseudo particles reach the discharge port of the drum mixer 1 is 80 seconds. Limestone having a particle diameter of 1.9 mm was added as the powder raw material 4 and powder coke having a particle diameter of 1.9 mm was added as the solid fuel-based powder raw material 5. The specific method is that the residence time until the pseudo particles reach the discharge port becomes 80 seconds by adjusting the tip position of the screw conveyor disposed so as to be able to advance and retreat in the longitudinal direction in the drum mixer 1 from the discharge port. Limestone powder material 4 and solid fuel powder material 5 were added to the position. Therefore, the exterior time is 80 seconds.

  Moreover, as Comparative Example 2, a raw material for sintering was manufactured under the same conditions as Comparative Example 1 except that the exterior time was 40 seconds.

  When the raw materials for sintering of the inventive examples and comparative examples 1 and 2 were sintered, the sintered raw materials of the inventive example and comparative example 1 had sufficient strength. This indicates that the CF melt was generated on the surface of the raw material for sintering.

  However, the sinter produced from the raw material for sintering of Comparative Example 2 was inferior in strength to the sintered ore using the inventive raw material for sintering and Comparative Example 1. This indicates that the limestone powder raw material 4 and the solid fuel powder raw material 5 could not be uniformly coated on the surface of the pseudo particles, so that the generation of CF melt was uneven.

  That is, according to the present invention, when manufacturing a raw material for sintering, the exterior time can be shortened, and a sintered ore having sufficient strength can be obtained by sintering the raw material for sintering.

It is a layout view schematically showing an example of an apparatus for manufacturing a raw material for sintering by applying the present invention.

Explanation of symbols

1 Drum mixer 2 Iron ore 3 Raw material containing SiO ₂ 4 Limestone powder raw material 5 Solid fuel powder raw material 6 Sintering raw material

Claims (3)

In the method for producing a raw material for sintering, in which a raw material is charged into a drum mixer and granulated as a pretreatment of a process for producing a sintered ore using a downward suction droidoid type sintering machine, the inlet of the drum mixer is used. The iron ore and the SiO ₂ -containing raw material are charged and granulated, and the residence time until the pseudo particles granulated in the drum mixer reach the discharge port of the drum mixer is 10 to 50 seconds. A limestone powder material having an average particle diameter of 250 μm to 1 mm and a solid fuel powder material having an average particle diameter of 250 μm to 1 mm are added in a region set in the middle of the downstream side of the range, and the limestone powder is delivered to the outlet. A method for producing a raw material for sintering, wherein the raw material and the solid fuel-based powder raw material are adhered to the surface of the pseudo particles.   The method for producing a raw material for sintering according to claim 1, wherein the residence time is 30 to 50 seconds. A screw conveyor is inserted into the drum mixer from the discharge port, and the limestone powder raw material and the solid fuel powder raw material are dropped from an end of the screw conveyor and added to the pseudo particles. Item 3. A method for producing a raw material for sintering according to Item 1 or 2.

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