JP2007138244A - Method for producing sintered ore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing sintered ore with which, when a large amount of porous iron ores inexpensive and abundant in resources such as maramanba ores are used as sintering raw materials, without requiring prliminary granulation or the like using special equipment, the granulation properties of the sintering raw materials are improved with a small addition amount of water while improving gas permeability upon sintering, and the yield of formed products in the sintered ores and productivity can be satisfactorily maintained. <P>SOLUTION: In the method for producing sintered ores, before at least iron-containing raw materials among sintering raw materials are mixed and granulated, among iron ores blended into the iron-containing raw materials, at least porous iron ores in which the amount of fine pores measured by a mercury pressure process is ≥0.05 cc/g are pulverized to have grain sizes so that fine powders having a grain diameter of ≤45 μm are included by ≥15% in the porous iron ores. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing sintered ore, and in particular to improve the granulation property of the sintered raw material and improve the productivity of sintering by pre-grinding the porous iron ore to be mixed with the sintered raw material. The present invention relates to a method for producing a sintered ore.

  Generally, the sintered ore used as a main raw material of the blast furnace iron manufacturing method is manufactured as follows.

  First, iron ore powder of about 10 mm or less, which is the main raw material of the sintered raw material, sintered reverse sinter, sintered sieving powder, iron-containing dust (iron-making dust, steel-making dust, scale, etc.) and other iron-containing raw materials, limestone, After adding dolomite, converter slag, serpentine, quartzite, peridotite and other carbonaceous materials such as coke powder and anthracite, the amount of water added is adjusted to a suitable amount in a granulator such as a drum mixer or pelletizer. Mixing and granulation are performed while adjusting the above, and the sintered raw material is converted into pseudo particles, and then charged into a sintering machine and fired. The sintered cake after firing is crushed and sized to form a sintered ore with a predetermined particle size. In addition, sintered powder with a particle size smaller than a predetermined particle size and sintered powder produced by disintegration during transportation to a blast furnace are called sintered refining and sintered sieve powder, respectively. Used as an iron-containing raw material.

  Here, the pseudo particles obtained by granulating a normal sintered raw material mainly have a structure in which fine particles having a particle size of 0.5 mm or less adhere to core particles having a particle size of 1 to 3 mm. By using such pseudo particles as the sintering raw material, it is possible to suppress the deterioration of air permeability due to fine powder particles in the sintering raw material packed layer (sintering bed) in the sintering machine and to improve the productivity of the sintering machine. .

  In recent years, from the viewpoint of effective utilization of iron resources, fine iron ore for pellets (pellet feed) as a raw material for sintering, fine iron ore for sintering with a high proportion of fine powder such as maramanba ore, and further generated in the iron making process. A lot of steelmaking dust is blended.

  In order to granulate a sintering raw material having a high proportion of fine iron ore, a granulating agent such as quick lime is added to the sintering raw material and mixed with a kneader (mixer), and then a drum mixer, A granulation method using a granulator having a high granulation capability such as a disk pelletizer having a higher granulation capability than that of a drum mixer has been performed. The pellet-like granulated product made of a sintering raw material having a high fine powder ratio obtained by this granulation method becomes a granulated product having a relatively high density. Therefore, when it is fired using a normal sintering machine, Oxygen diffusion into the particles is hindered, and combustion of the internal carbon material is delayed. For this reason, after obtaining the pellet-shaped granulated material which restricted the content rate of carbonaceous material and quicklime comparatively few by the said granulation method (primary granulation), further, carbonaceous material and quicklime (CaO containing auxiliary material) When the carbonaceous material and CaO-containing auxiliary material are sheathed on the surface of the granulated material by secondary granulation with a drum mixer or a disk pelletizer, and fired using a normal sintering machine, the surface of the granulated material There has also been proposed a method for improving the combustibility of carbonaceous materials and generating a binder phase mainly composed of calcium ferrite having excellent reducibility (see, for example, Non-Patent Document 1 and Patent Documents 5 to 7).

  In the granulation treatment process of the sintering raw material, the degree of adhesion of fine powder particles in the sintering raw material around the core particles, that is, the pseudo-granulating property of the sintering raw material is improved, and the pseudo particles obtained by granulation However, it is required to have the strength of pseudo particles that are difficult to collapse during conveyance to the sintering machine and in the sintering bed. In general, the pseudo-granulating property and the strength of pseudo-particles (difficult to collapse) of such a sintered raw material are the properties and grain size composition of the mixed raw material of the sintered raw material, particularly iron ore that occupies the main part of the sintered raw material. It is known that it is greatly influenced by the properties and particle size composition of stone.

  On the other hand, iron ore, which is the main raw material of sintering raw materials, has iron ores of various brands with various components and characteristics in the world, and generally these multiple ores of iron ore are sintered as iron-containing raw materials. Used in the raw material. Among these iron ores, high-quality hematite ore, which has been widely used as a raw material for sintering, is in the direction of depletion in terms of the world's iron ore resources. It is predicted that it will be dug up, and the use of an iron ore of an alternative brand is desired.

  Under these circumstances, in recent years, as a main raw material for sintering, Maramamba ore, which is cheaper and more abundant in resources compared to high-quality hematite ore, has attracted attention as a raw material for sintering.

  Maramamba ore is a general term for iron ore produced from the Maramamba iron ore deposit in Australia, with goethite (Fe2O3 · H2O) and martite (Fe2O3 having a magnetite crystal shape) as the main iron minerals. West Angelus ore is a typical iron ore.

  Table 1 shows the chemical and physical characteristics of typical iron ore used as a raw material for sintering in Japan. West Angelus ore is a major ore from the Australian Maramamba iron ore (hereinafter referred to as the Maramamba ore) and is a major hematite ore such as Hamasley and Newman, which are the major ores from the Australian Blockman iron deposit. The content of crystal water (CW) is as high as about 5%, compared to the main ore (hereinafter referred to as pisolite ore) produced from the Australian pisolite iron deposit, commonly known as high crystal water ore. ) Is low compared to Robe River and Yandi. Moreover, it has the particle size distribution with many fine powder parts of 0.25 mm or less. The reason why the Mara Mamba ore has a high content of crystallization water (CW) like the pyrolite ore is due to the fact that the main iron mineral of these iron ores contains a large amount of goethite (Fe2O3 · H2O). Further, as will be described later, the inventors have confirmed that maramamba ore has a porous mineral structure containing a large amount of martite (Fe2O3 having a magnetite crystal shape) as a main iron mineral.

  Maramamba ore is available as a stable raw material and is considered to be an inexpensive iron ore that is used as a raw material for sintering. However, because Mara Mamba ore contains a large amount of martite having a porous structure as the main iron mineral, in addition to high water absorption, the amount of water added during granulation is high, and the particle size distribution is high in fine powder. There was a problem that the granulation property was bad due to having. In addition, in order to obtain a good granulated product due to the high water absorption of Mara Mamba ore, the water content of the granulated product of the sintering raw material is inevitably increased, and the content of crystal water of the Mara Mamba Ore is increased. As a result, the amount of moisture brought into the packed bed of the sintering raw material increases, which deteriorates the air permeability during sintering and reduces the combustion efficiency of the carbonaceous material. Become. Furthermore, the moisture brought into the packing layer of the sintering raw material evaporates in the process of burning and sintering the carbon material sequentially from the upper part to the lower part of the sintering raw material packing layer, and then the sintering is performed at a low temperature. It condenses in the lower part of the raw material layer to form a moisture condensation zone. In this moisture condensation zone, the pseudo particles at the time of charging absorb a large amount of surrounding moisture, and the structure deforms and collapses, so the air permeability of the entire sintering raw material layer at the time of sintering deteriorates, resulting in sintering. It is the main factor that decreases the productivity and product yield of the ore.

  For this reason, when maramamba ore is used as a sintering raw material, in order to maintain the productivity and product yield of the sintered ore, the blending ratio is limited to about 10% or less, and it is of good quality as other iron ore. Currently, hematite main ore is used in combination.

  However, as mentioned above, Australia, which is the main producer of iron ore used in Japan, is depleted of high-quality hematite ore from the Brockman deposit and is produced into the pisolite deposit and further to the Maramamba deposit. There is a move to move, and in the near future Mara Mamba ore is expected to become the mainstay of future Australian iron ore. Therefore, it is desired to improve the granulation property without increasing the amount of added water when granulating a sintered raw material containing a large amount of maramamba ore.

  In order to solve the problem caused by the decrease in the granulating property of porous iron ore such as the above-mentioned maramanba ore, for example, Patent Document 1 discloses that “a porous iron ore or a surface like a goethite is smooth and When using a dense ore as a part of the sintering raw material, the surface of the porous iron ore or goethite is smooth and dense before mixing and granulating with a mixer in a normal granulation line. `` Sintering raw material pretreatment method characterized in that ore is individually granulated on separate lines according to its physical properties, then mixed with other general brand ores in a mixer and granulated '' ing.

  High crystal water and low gangue iron ore, such as maramamba ore, are porous and inferior to other general iron ores. Therefore, as described in Patent Document 1, granulation suitable for the physical properties is individually provided in a separate line. However, there are disadvantages in that the manufacturing cost is increased and the strength of the whole granulated product cannot be significantly improved.

  Patent Document 2 states that “when using porous iron ore (for example, Australian maramamba ore) as part of the sintering raw material, before mixing and granulating with a mixer in a normal granulation line, There is disclosed a “sintering raw material pretreatment method” characterized in that the porous iron ore is treated with water in a separate line, and then mixed and granulated with another general brand ore by a mixer.

  Although it is effective to perform a water treatment as described in Patent Document 2, it is difficult to significantly improve the strength of the entire granulated product. In addition, the increase in moisture content in the granulated product increases the amount of moisture brought into the sintered raw material packed bed during sintering in addition to the high crystallization water content of maramanba ore, thereby expanding the range of moisture condensation zones. For this reason, the air permeability deteriorates due to the pseudo particle collapse in the water agglomeration zone, which is a main factor for reducing the productivity and product yield of the sintered ore.

  Patent Document 3 states that “a granulation line in which sintered raw materials are mixed and granulated and pretreated, and one granulation line having a low CaO component for treating a main raw material group such as iron ore and coke; It is divided into two series granulation lines with the other granulation line with a high CaO component to process other raw material groups such as other ores, and the ore of the other raw material group in the other granulation line includes maramamba ore etc. Pretreatment of sintered raw materials characterized by using finely divided ore of high crystal water, adding quick lime separately to both granulation lines, and granulating main raw material group and other raw material groups with quick lime binder Method "is described.

  In the method described in Patent Document 3, a secondary raw material tank, a limestone tank, and a binder tank are newly installed in addition to a plurality of ore tanks and granulated in advance, so that it is extremely large equivalent to installing a new granulation processing facility. Capital investment is required, leading to an increase in manufacturing costs.

In Patent Document 4, when soft / porous iron ore is used as part of the sintering raw material, the absorption of water into the soft / porous iron ore is suppressed by adding an additive such as sugar or molasses. A method is disclosed.
In the method described in Patent Document 4, when an additive such as sugar or molasses is added and used, these are generally expensive, so that the production cost increases and the strength of the granulated product cannot be significantly improved. Although the additive has the effect of increasing the viscosity at the time of granulation of the sintered raw material and increasing the strength of the granulated product, the pseudo particles are formed in the moisture condensation zone formed at the bottom of the sintered raw material packed layer at the time of sintering. Since the effect of suppressing the absorption of a large amount of moisture from the surroundings and suppressing the collapse of the pseudo particles is low, it causes the deterioration of air permeability during sintering, and the main factor that decreases the productivity and product yield of sintered ore Become.

  In Patent Document 8, limonite ore containing a large amount of crystal water is mixed with lime powder and scale, and pulp waste liquid containing lignin sulfonic acid as an active ingredient is added and granulated, and then mixed with the remaining raw materials. Then, a method of granulating again is disclosed, and the use of maramamba ore is exemplified.

  In the method described in Patent Document 8, since the effect of improving the granulating property of lignin sulfonic acid is not sufficient, when a large amount of maramamba ore is blended, the productivity is significantly reduced.

In addition, as an example of use of conventional maramamba ore, there is a track record of using a large amount of maramamba ore by applying the HPS method (Non-Patent Document 1) at Fukuyama Steel Works, Japan Patent Pipe Co., Ltd. The HPS method disclosed in No. 6 and Patent Document 7 and the like is a technology that enables a large amount of fine ore with a small particle size to be introduced by introducing dish-type granulation equipment into the granulation process and adding more limestone than before. However, this is not a method considering granulation centering on an existing drum mixer. In addition, the introduction of the plate-type granulation equipment to the existing sintering machine requires a huge capital investment and running cost.
Japanese Laid-Open Patent Publication No. 52-49905 (Publication Date: April 21, 1977) JP 52-49906 A (published on April 21, 1977) Japanese Patent Laid-Open No. 5-9601 (Publication date: January 19, 1993) JP 10-502417 A (publication date March 3, 1998) JP 63-149333 A (publication date June 22, 1988) JP 63-149334 A (publication date June 22, 1988) JP 63-149336 A (publication date June 22, 1988) JP-A-5-25556 (publication date February 2, 1993) Noboru Sakamoto, 4 others, “Fundamental examination and quality evaluation on production conditions of new agglomerates for blast furnace”, Iron and Steel, Japan Iron and Steel Institute, 73rd (1987) No. 11, p62

  Conventional granulation methods for sintered raw materials as disclosed in the above-mentioned patent documents are difficult to apply to sintered raw materials containing a large amount of maramanba ore, which has poor granulation properties compared to other ores. And practicality is low.

  The present invention is less expensive and does not require pre-granulation using special equipment when using a large amount of porous iron ore such as maramamba ore as a sintering raw material, which is abundant in resources. Provided is a method for producing a sintered ore which can improve the granulation property of the sintering raw material with the amount of water added, improve the air permeability during sintering, and maintain good product yield and productivity of the sintered ore. For the purpose.

The method for producing a sintered raw material and sintered ore according to the present invention has the following features in order to achieve the above-described object.
(1) In the manufacturing method of the sintered ore which inserts and sinters the sintering raw material which consists of an iron-containing raw material, an auxiliary raw material, and a carbonaceous material to a sintering machine, at least iron-containing raw material of the said sintering raw materials Before mixing and granulating, among the iron ores blended in the iron-containing raw material, at least a porous iron ore having a fine pore amount measured by a mercury intrusion method of 0.05 cc / g or more is used. A method for producing a sintered ore, comprising pulverizing the iron ore so that the fine particle having a particle size of 45 μm or less in the iron ore has a particle size of 15% or more.
(2) The porous iron ore according to claim 1, wherein the porous iron ore is sieved with a sieve of 2 to 7 mm before pulverization, and the sieving of the porous iron ore is pulverized. Production method.
(3) The sintering according to (1) or (2) above, wherein the pulverization of the porous iron ore is performed together with iron ore having a particle size of 3 mm or less other than the porous iron ore and an auxiliary material. Manufacturing method of ore.
(4) The method for producing a sintered ore according to (3) above, wherein the iron ore having a particle size of 3 mm or less other than the porous iron ore is a fine iron ore for pellets.
(5) The porous iron ore is composed of one or more of maramamba ore, high phosphorus blockman ore, pisolite ore, and low adjacent blockman ore, according to the above (1) to (4) The manufacturing method of the sintered ore in any one.
(6) The method for producing a sintered ore according to any one of (1) to (5), wherein the mixing and granulation are performed by adding water and mixing and granulating with a drum mixer.
(7) The mixing or granulation is performed by adding a dispersant together with water, and mixing and granulating with a drum mixer, wherein the sintered ore according to any one of (1) to (5) above Production method.
(8) The above mixing and granulation are characterized in that after adding a dispersant together with water and mixing with a kneader, granulation is performed with any of a drum mixer, a disk pelletizer, or a pan pelletizer ( The manufacturing method of the sintered ore as described in any one of 1)-(5).
(9) In the granulation, water or water and a dispersant are added. The method for producing a sintered ore according to (8) above, wherein
(10) The mixing and granulation are performed by adding a dispersant together with water, mixing with a kneader, and performing primary granulation with any of a drum mixer, a disk pelletizer, or a pan pelletizer, and the granulated product. Carbonaceous material or carbonaceous material and CaO-containing auxiliary material are added to the material, and secondary granulation is performed with either a drum mixer, a disk pelletizer, or a pan pelletizer, so that the surface of the granulated material contains carbonaceous material or carbonaceous material and CaO. The method for producing a sintered ore according to any one of (1) to (5) above, wherein an auxiliary material is packaged.
(11) The method for producing a sintered ore according to (10) above, wherein water or water and a dispersant are added in either or both of the primary granulation and the secondary granulation. .
(12) The method for producing a sintered ore according to any one of (8) to (11), wherein a Redige mixer is used as the kneader.
(13) The sintered ore according to any one of (10) to (12) above, wherein one or two of carbonaceous material and CaO-containing auxiliary raw material are added when mixing with the kneader. Manufacturing method.
(14) The dispersant is added in the range of 0.001% by mass to 1% by mass with respect to the total amount of the sintered raw material excluding the carbonaceous material, including at least the iron-containing raw material to be mixed and granulated. The method for producing a sintered ore according to any one of (7) to (13), wherein the method is characterized in that.
(15) After mixing the dispersing agent and the sintering raw material including at least the iron-containing raw material to be mixed and granulated and excluding the carbonaceous material, the mixed composition is mixed with a solid content of 10 g in a 100 ml measuring cylinder. After adding ion-exchanged water so that the total amount becomes 100 ml and stirring for 10 seconds, the amount of fine particles floating in water after standing for 10 minutes is the solid content of the mixed composition. Adjusting the addition amount of the dispersant with respect to the total amount of the sintered raw material excluding the carbonaceous material and including at least the iron-containing raw material to be mixed and granulated so as to be 2% by weight or more. (14) The method for producing a sintered ore according to (14).
(16) The method for producing a sintered ore according to any one of (7) to (15), wherein the dispersant is a polymer compound having an acid group and / or a salt thereof.

  When producing sintered ore using a large amount of porous iron ore, such as cheap and resource-rich maramamba ore, as a sintering raw material, without prior granulation using special equipment, etc. In addition, the granulation property and adhesion of the sintered raw material can be improved with a small amount of water added. As a result, the air permeability during sintering can be improved, and the product yield and productivity of the sintered ore can be improved.

  First, the technical idea of the present invention will be described.

  Conventionally, limonite has a porous structure compared to magnetite and hematite, and thus has a high water absorption and is known to have a tendency to increase moisture necessary for proper granulation. The inventors measured the fine pore volume, water absorption, and granulation properties of typical iron ore brands used as sintering raw materials in Japan, and the fine pore volume and water absorption of iron ore were granulated. The effect on sex was investigated.

  FIG. 10 is a diagram showing the relationship between the amount of fine pores of various iron ores and water absorption, and FIG. 11 is a diagram showing the relationship between the water absorption of various iron ores and the GI value (pseudoparticle index).

  In addition, the amount of fine pores in iron ore is obtained by measuring the amount of fine pores having a pore diameter of about 0.1 to 10 μm using a mercury intrusion porosimeter.

  The iron ore absorbs 200 g of iron ore sample in water for 20 minutes, and then rotates at 800 rpm for 15 minutes in a centrifuge to determine the amount of water remaining in the ore sample per mass of iron ore. It is the value converted into the amount of water.

  Moreover, the GI value (pseudo-particleization index) of iron ore is one of the evaluation indexes of pseudo-granulation obtained by the following formula (for example, refer to page 9 of Steelmaking Research No. 288 (1976)), and nuclear particles The ratio of fine powder particles adhering to the surface of is shown. The larger this GI value, the better the effect of adhering fine powder particles to the surface of the core particles, the better the air permeability of the sintered layer, and the improved productivity of the sintered ore. The amount of water added for pseudo-granulation of iron ore was 7% (constant).

GI (%) = (ratio of raw material of 0.25 mm or less before granulation−ratio of raw material of 0.25 mm or less after granulation) / (ratio of raw material of 0.25 mm or less before granulation) × 100
FIG. 10 shows that the water absorption of iron ore increases as the amount of fine pores in the iron ore increases, and FIG. 11 shows that the GI value (pseudo-particleization index) of iron ore decreases as the water absorption of iron ore increases. . From these figures, when the amount of fine pores in the iron ore exceeds 0.05 cc / g, the water absorption of the iron ore becomes 5 (g-H ₂ O / g-Ore) or more, and the amount of added water Is constant (7%), the moisture is lost to the fine pores in the iron ore, resulting in a decrease in the amount of water that contributes to proper granulation. As a result, the iron ore has a GI value (pseudoparticle index) of 80 or less. The granulating property is lowered to the point.

  10 and 11, the iron ores having a fine pore volume of less than 0.05 cc / g correspond to, for example, riodose (hematite ore, H1 in FIG. 10) and carajas (hematite ore, H2 in FIG. 10). Iron ores having a pore volume of 0.05 cc / g or more are Mount Newman (hematite ore, H3 in FIG. 10), Yandi (pisolite ore, P1 in FIG. 10), Robe (pisolite ore, P2 in FIG. 10), MAC ( This corresponds to the Mara Mamba Ore, M1 in FIG. 10, West Angelus Ore (Mala Manba Ore, M2 in FIG. 10), and Salgaonka (Goesite Ore, G in FIG. 10).

  In addition, when granulating using a porous iron ore having a fine pore amount of 0.05 cc / g or more as a sintering raw material, the amount of added water is increased, and by ensuring moisture that contributes effectively to granulation, To a certain extent, granulation can be improved. However, an increase in the amount of added water during granulation not only deteriorates the fuel consumption rate due to an increase in the latent heat of vaporization of the water when the granulated product is sintered, but also increases the combustion zone of the sintered raw material packed bed. Expanding the range of the moisture condensation zone formed below, the pseudo particles absorb a large amount of moisture from the surroundings in the moisture condensation zone, and the pseudo particles collapse, leading to deterioration in air permeability during sintering, and sintering ore Cause a decrease in productivity and product yield.

  Based on the influence on the fine pore volume and water absorption granulation property (GI value) of each iron ore described above, the present inventors have developed a GI value (pseudoparticles) when granulation is performed under a constant amount of added water. In order to improve the granulation property when the iron ore is used as a sintering raw material for porous iron ore with a fine pore volume of 0.05 cc / g or more, which is markedly reduced in granulation property) The method of was examined.

  As shown in FIG. 10, the inventors of the present invention have a large cause that the porous iron ore such as maramamba ore has a low granulation property (GI value). These iron ores have a large amount of fine pores and increase water absorption. Therefore, the pre-grinding treatment to destroy the porous structure of these iron ores was examined.

  Conventionally, when porous iron ores such as maramamba ore and pisolite ore are used as a sintering raw material, if fine particles with a particle size of 0.5 mm or less increase, core particles with a particle size of 1 to 3 mm are relatively reduced. Because it becomes difficult to make pseudo-granulated particles, pulverizing porous iron ores such as maramamba ore and pisolite deteriorates the granulation property of the sintering raw material and reduces the air permeability and productivity during sintering. It was thought that it was not adopted.

  As shown in Table 1, in particular, maramamba ore is a highly crystalline hydrous iron ore as well as pisolite ore, and contains a large amount of fine particles of 0.25 mm or less compared to pisolite ore. In order to maintain the granulation property and air permeability during sintering, the blending ratio to the sintering raw material was limited to be low.

  However, according to the study by the inventors, porous iron ores such as maramamba ore contain a large amount of porous structure (such as martite structure (Fe2O3 having a magnetite crystal shape)) as the main iron mineral. It was found that when the porous iron ore was pulverized, the porous structure was selectively pulverized to form fine particles, and the other mineral structures remained without being pulverized. Moreover, it was confirmed that when porous iron ore such as a martite structure was pulverized, it was destroyed from pores that were structurally fragile, and the particles after the destruction became ultrafine particles having a very small particle size.

  FIG. 1 shows that before the pulverization of maramamba ore (West Angelus ore with a fine pore volume: 0.091 (cc / g)), which is a porous iron ore (FIG. 1 (a): particle size of 45 μm or less is 12%). The cross-sectional structure | tissue photograph at the time of carrying out the microscope observation about each after grinding | pulverization (FIG.1 (b): The particle size of 45 micrometers or less is 20%) is shown. FIG. 2 shows photographs of a cross-sectional structure of the martite structure (porous structure structure) in the maramamba ore before and after pulverization shown in FIG.

  In the porous iron ore sample before pulverization (FIG. 1 (b)), many martite structures (M in the figure) having a porous structure with a size of 50-100 μm are observed, whereas the same after pulverization. In the sample (FIG. 1 (b)), the martite structure (M in FIG. 1 (a)) having a porous structure before pulverization may be crushed into a fine martite structure (M1 in FIG. 1 (b)). I understand. In other words, by pulverizing porous iron ore such as maramamba ore, while selectively pulverizing and refining porous structure structures (such as martite structures) that increase water absorption and reduce granulation, It was found that the core particles (particle size 1 to 3 mm) necessary for good pseudo-particle formation can be maintained.

  Further, as can be seen from FIG. 2, when the porous structural structure (martite structure) is crushed, it is broken from the structurally fragile pores, and the broken particles have a particle size of 45 μm or less. It was found that a large number of ultrafine particles having a very small diameter were produced. In general, fine particles adhering to the periphery of core particles (particle size 1 to 3 mm) constituting pseudo particles are known to have a particle size of 0.5 mm or less, and intermediate particles having a particle size of 0.5 to 1 mm are pseudo particles. It is thought that there is little contribution in constructing.

  Further, according to the study by the inventors, among the fine particles having a particle size of 0.5 mm or less, the ultrafine particles having a particle size of 45 μm or less are particularly easily dispersed with a small amount of added water during granulation because of high dispersibility in water. In addition, it is possible to effectively and efficiently adhere to the core particles and to increase the cohesion of water when the ultrafine particles are uniformly dispersed in the water, thereby improving the pseudo-particle property and adhesion. I understood.

  In addition, the dispersibility of the ultrafine particles in water is higher as the particle size is smaller, and the ultrafine particles having a particle size of 10 μm or less are further highly dispersible in water.

Further, according to the study by the inventors, some of the ultrafine particles having a particle size of 45 μm or less are aggregated and clustered with each other in water and have a large apparent particle size. By adding a dispersing agent having an enhancing effect, the ultrafine particles that have been clustered are separated and dispersed uniformly in the moisture that is improved by the action of the ultrafine particles, so that the pseudoparticulateness and adhesion are further improved. I have also confirmed that.
Incidentally, granulation additives such as molasses that have been conventionally added to increase the viscosity of the added water during granulation (for example, see Patent Document 4) are conversely in ultrafine particles having a particle size of 45 μm or less in the water. Since dispersibility is inhibited, it is not preferable.

  FIG. 3 is a granulated product obtained by pulverizing the maramamba ore which is the porous iron ore shown in FIGS. 1 and 2 and adding water (7%) and granulating (FIG. 3 (a)). And the micrograph at the time of carrying out the microscope observation of the surface of the granulated material obtained by granulating by adding a water | moisture content (7%) and a dispersing agent (sodium polyacrylate (PA): 0.04%) is shown. From FIG. 3, by pulverizing Mara Mamba ore, which is a porous iron ore, ultrafine particles having a particle size of 45 μm or less generated when the porous structural structure (martite structure) in the ore is selectively pulverized are contained in water. Because of its high dispersibility, it is easy to move in water, agglomerate and adhere around the core particles having a particle diameter of 1 to 3 mm that remain without being pulverized, and between the fine particles constituting the adhered powder, It can be seen that strong pseudo-particles are generated by increasing the adhesion between the particles and the core particles. In addition, by adding moisture and a dispersing agent during granulation, the effect of improving the dispersibility of ultrafine particles having a particle size of 45 μm or less in water is further enhanced. It can be seen that stronger pseudo-particles are generated by moving around and agglomerating around the core particles.

  The present invention has been made on the basis of the above knowledge and technical idea, and is a sintered ore that charges and sinters a sintered raw material comprising an iron-containing raw material, an auxiliary raw material, and a carbonaceous material into a sintering machine. In the manufacturing method, before mixing and granulating at least the iron-containing raw material among the sintered raw materials, among the iron ores blended in the iron-containing raw material, the amount of fine pores measured by at least the mercury intrusion method is 0. The porous iron ore having a particle size of 0.05 cc / g or more is pulverized so that the fine powder having a particle size of 45 μm or less becomes a predetermined amount or more. Thereby, while selectively destroying the porous structural structure contained in a large amount of porous iron ore having a fine pore amount of 0.05 cc / g or more which lowers the granulation property of the sintered raw material, the water absorption is suppressed, It is possible to increase the number of ultrafine powder particles with a particle size of 45 μm or less, which has high dispersibility even with a small amount of added water while retaining the core particles necessary for pseudo-particle formation, and has the effect of increasing the cohesive strength of water. Graininess and adhesion can be remarkably improved.

  Moreover, in order to further improve the dispersibility in the added water of the ultrafine particles having a particle size of 45 μm or less, and to improve the granulation and adhesion of the sintered raw material more effectively and efficiently with a small amount of added water, It is preferable to add a dispersant having an effect of enhancing the dispersibility of fine powder particles having a particle size of 45 μm or less together with moisture during granulation.

  Details of the present invention will be described below.

  The present invention selectively destroys the porous structure in the iron ore when pulverizing the porous iron ore having a fine pore amount of 0.05 cc / g or more which lowers the granulation property of the sintered raw material. In addition to suppressing water absorption and increasing the number of ultrafine powder particles with a particle size of 45 μm or less, which is highly dispersible even with a small amount of added water while retaining the core particles necessary for pseudo-particle formation, the granulation properties of the sintering raw material are increased. There is a need to improve.

  When the present inventors pulverize Mara Mamba ore (West Angelus ore with a fine pore volume: 0.091 (cc / g)), which is a porous iron ore, and then add water to the pulverized product and granulate In addition, by changing the content of ultrafine particles having a particle size of 45 μm or less after pulverization and the amount of added water during granulation, from the measurement results of the adhesion force and pseudo-granulating property (GI value) of the granulated product, The optimum grinding condition of porous iron ore was studied.

  FIG. 4 shows the amount of added water when granulating maramamba ore (a fine pore amount: 0.091 (cc / g) West Angelus ore), which is a porous iron ore, and a fine powder having a particle size of 45 μm or less after pulverization FIG. 5 shows the relationship between the content and the adhesion of the granulated product. FIG. 5 shows the amount of added water during granulation, the content of fine powder having a particle size of 45 μm or less after pulverization, and the pseudo-granulating property of the granulated product (GI Value).

  In addition, the adhesive force of the granulated material of FIG. 4 was measured by the tensile fracture method.

  From FIG. 4 and FIG. 5, when the amount of added water at which the adhesion force and pseudo-granulating property (GI value) of the granulated product are almost maximized is compared with the condition of 5 to 7%, It can be seen that, as the content of fine particles having a particle size of 45 μm or less increases, the adhesion and pseudo-granulating property (GI value) of the granulated product are improved. Usually, the adhering force of the granulated material required to maintain good air permeability during sintering and ensure the productivity and product yield of sintered ore is 30 g / cm 2 or more, and pseudo granulation The property (GI value) is 80% or more. In addition, the increase in the amount of added water during granulation not only deteriorates the fuel consumption rate due to the increase in the latent heat of vaporization of the water when the granulated product is sintered, but also the combustion zone of the sintered raw material packed bed. Expanding the range of the moisture condensation zone formed below, the pseudo particles absorb a large amount of moisture from the surroundings in the moisture condensation zone, and the pseudo particles collapse, leading to deterioration in air permeability during sintering, and sintering ore Therefore, it is preferable to perform granulation with as little added water as possible.

  Therefore, based on the examination results of FIGS. 4 and 5, in the present invention, the adhering force is 40 g / cm 2 or more even with a relatively small amount of water added at the time of granulation of 5%, and the pseudo-granulating property (GI value). ) Is 80% or more, and as a pulverization condition for producing a granulated product excellent in strength and granulation property, a fine iron content with a particle size of 45 μm or less is obtained after pulverizing a porous iron ore of 0.05 cc / g or more. Is limited to a condition such that is 15% or more.

  As a result, a porous structure (such as a martite structure) that causes a decrease in the granulation property of the sintering raw material is selectively destroyed to suppress water absorption, and a particle size of 45 μm or less with high dispersibility even with a small amount of added water. The fine powder particles can be increased, the adhesion to the core particles and the pseudo-particle formation property (GI value) can be improved, and the air permeability, productivity and product yield during sintering can be improved.

  Next, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 6 shows the composition of a sintered ore that mixes and granulates a sintered raw material composed of an iron-containing raw material, an auxiliary raw material, and a carbonaceous material, and is mixed with the iron-containing raw material before the mixing and granulating. Among iron ores, porous iron ore with a fine pore volume measured by mercury porosimetry of 0.05 cc / g or more is pulverized, and fine powder with a particle size of 45 μm or less in the porous iron ore contains 15% or more An embodiment in the case of a granularity is shown.

  As shown in FIG. 6, first, the porous iron ore 1 having a fine pore volume measured by the mercury intrusion method is 0.05 cc / g or more includes other iron-containing raw materials and auxiliary raw materials other than the porous iron ore 1. And before mixing with the carbonaceous material 3 and granulating, it is pulverized in advance using a pulverizer 2 such as a roller press or a ball mill to obtain a pulverized product. The type of pulverizer and the pulverization conditions are not particularly limited, and 15% or more of fine powder having a particle size of 45 μm or less in the porous iron ore having the fine pore amount specified in the present invention of 0.05 cc / g or more is contained. If it can grind | pulverize so that it may become the particle size to achieve, the objective and effect of this invention can be achieved. For example, in the example of the microphotograph before and after pulverization of the Maramamba ore (West Angelus ore having a fine pore amount: 0.091 (cc / g)) shown in FIG. Using a Maramamba ore containing a grain size of 125 mm or less and a grain size of 45 μm or less, 12%, while applying a pressure of about 15 to 35 KN / cm per roll width, a particle size of 45 μm or less is contained by 20%. A pulverized product was obtained.

  The pulverized material of the porous iron ore 1 is supplied to the granulator 4 together with other iron-containing raw materials other than the porous iron ore 1, auxiliary materials, and the carbonaceous material 3, mixed and granulated, and then sintered. 5 can be used to make a sintered ore.

The embodiment shown in FIG. 6 shows an example in which the pulverized product of the porous iron ore 1 is mixed and granulated together with other iron-containing raw materials, auxiliary raw materials, and the carbonaceous material 3. Of the sintered raw materials, the auxiliary raw material and the carbonaceous material are not necessarily mixed and granulated. That is, when the pulverized product of the porous iron ore 1 and other iron-containing raw materials other than this are mixed and granulated, the auxiliary raw material and the carbonaceous material are added and sintered by the granulator 4, or Even when the pulverized product of the porous iron ore 1, other iron-containing raw materials other than this, and auxiliary materials are mixed and granulated, and then added with a carbonaceous material and sintered by the granulator 4, By pulverizing the iron ore 1, the above-described objects and effects of the present invention are exhibited.
Moreover, the pulverization of the porous iron ore 1 is not limited to the case where only the porous iron ore 1 is pulverized alone by the pulverizer 2, the porous iron ore 1 and other iron-containing raw materials, Even when the auxiliary raw materials are pulverized together by the pulverizer 2, the porous iron ore specified in the present invention has a particle size containing 15% or more of fine powder having a particle size of 45 μm or less in the porous iron ore. The purpose and effect of the present invention described above are exhibited.

  As the granulator 4 used for mixing and granulating the sintering raw material, the granulating ability of a drum mixer, a pan pelletizer, a disk pelletizer, etc. that are generally widely used in the sintered ore process is high. A granulator is used. As shown in FIG. 6, by adding water to the pulverized product of the porous iron ore 1, other iron-containing raw materials, auxiliary raw materials, and the carbonaceous material 3, only one granulator 4 is used for good mixing and production. In order to perform granulation, it is preferable to use a drum mixer as the granulator 4.

  Moreover, the dispersibility in the water | moisture content of the ultrafine particle | grains of 45 micrometers or less of particle size contained in the ground material of the said porous iron ore 1 is improved by adding a dispersing agent with water at the time of the said mixing and granulation. This is preferable because the granulation property and adhesion of the sintered raw material are further improved.

  In the present invention, the dispersant is an effect of promoting dispersibility in water of ultrafine particles having a particle diameter of 45 μm or less contained in the pulverized product by adding together with water at the time of granulating the sintered raw material. As long as it has, it is not limited to an inorganic compound, an organic compound, a low molecular compound or a high molecular compound, and is not particularly limited.

  In the present invention, the effect of the dispersing agent, that is, the dispersibility in water of fine particles having a particle size of 45 μm or less contained in the pulverized product of the porous iron ore during granulation is promoted, and the sintering raw material is produced. In order to obtain the effect of improving the grain property and adhesion, the dispersant contains at least an iron-containing raw material to be mixed and granulated, and is a sintered raw material excluding carbonaceous materials, for example, as shown in FIG. Is preferably added in the range of 0.001% by mass to 1% by mass with respect to the total amount of the pulverized product of the porous iron ore 1, other iron-containing raw materials, and auxiliary raw materials. In the present invention, the amount of the dispersant used may be set as appropriate so as to obtain the amount of dispersed fine particles according to the type of dispersant used and the type and combination of the raw materials for iron making used, and is particularly limited. Although not intended, it is preferably in the range of 0.001% by weight or more and 1% by weight or less, more preferably in the range of 0.005% by weight or more and 0.5% by weight or less with respect to the raw material for iron making. When the amount of the dispersant used is less than 0.001% by weight, the effect of the dispersant is not exhibited, and the pseudo-granulating property and the adhesive force are not sufficiently improved. Moreover, when 1 weight% or more of a dispersing agent is used, since viscosity becomes high and granulation may not be performed as a result, it is not preferable.

  The inventors of the present invention have found that ultrafine particles having a particle size of 200 μm or less, particularly 45 μm or less, and even ultrafine particles having a particle size of 10 μm or less contained in the sintering raw material are uniformly dispersed in the water, so Experimentally confirming that the cohesive force is increased and the pseudo-particle property and adhesion force are improved, a dispersibility test for evaluating the ease of dispersion of the ultrafine particles in water has already been proposed.

  This dispersibility test is a method in which a sintering raw material is dispersed in water at a predetermined ratio, and the amount of fine particles suspended (dispersed) in water after a predetermined time (dispersed fine particle amount) is measured. It has been confirmed that when the amount of dispersed fine particles is 2% by weight or more based on the total amount of the sintered raw materials dispersed in water, the pseudo-granulating property and the adhesion force are improved.

  Specifically, the dispersibility test is carried out by the following method. First, a sintering raw material is collected in a 100 ml measuring cylinder so that the solid content becomes 10 g, and ion-exchanged water is added to this so that the total amount becomes 100 ml and stirred for 10 seconds. The amount of dispersed fine particles (dispersed fine particle amount) is measured. Since the particles having a large particle size and the particles which are not dispersion-stabilized contained in the sintering raw material settle while being left to stand for 10 minutes, all of the dispersion liquid after being left for 10 minutes is extracted, and the remaining sedimented particles are set to 110. By evaporating to dryness using a drier at 0 ° C., measuring the dry weight, and calculating the weight loss, the weight of the fine particles suspended (dispersed) in the dispersion can be obtained. .

  By this dispersibility test, the dispersibility in water of fine powder particles having a particle diameter of 45 μm or less contained in the pulverized product of the porous iron ore in the present invention can be evaluated.

  Therefore, in the present invention, in order to ensure the effect of improving the granulation property by the addition of the dispersant, the dispersibility test, that is, at least the iron-containing raw material to be mixed and granulated is used. Sintering raw material including and excluding the carbonaceous material, for example, in the case shown in FIG. 6, after mixing the pulverized porous iron ore 1, other iron-containing raw material, and auxiliary raw material, The amount of fine particles floating in water after being collected in a 100 ml graduated cylinder so that the solid content is 10 g, adding ion-exchanged water so that the total amount is 100 ml and stirring for 10 seconds. Sintered raw material including at least an iron-containing raw material to be mixed and granulated and excluding carbonaceous material, for example, so that the amount of the fine particles is 2% by weight or more of the solid content of the mixed composition, In the case shown in FIG. Pulverized porous iron ore 1, other iron-containing material, and, it is desirable to adjust the amount of the dispersing agent to the total amount of the auxiliary raw material.

  In addition, as the dispersant in the present invention, a polymer compound having an acid group and / or a salt thereof is preferable. Among these, carboxymethyl cellulose (CMC), lignin (LG), sodium polyacrylate (PA) having a weight average molecular weight of 1,000 or more and 100,000 or less, or ammonium polyacrylate has high dispersibility of fine particles and is inexpensive in price. Therefore, it can be used most preferably.

  In the embodiment of the present invention shown in FIG. 6, water, preferably water and a dispersant are added to the pulverized product of porous iron ore 1, other iron-containing raw materials, auxiliary raw materials, and carbonaceous material 3. An example of mixing and granulating with one granulator 4, preferably a drum mixer was shown. In the present invention, at least the iron-containing raw material among the sintered raw materials, for example, in the case shown in FIG. 6, the pulverized product of the porous iron ore 1, other iron-containing raw materials, auxiliary materials, and the carbonaceous material 3 together with water. In the case of adding a dispersant and mixing and granulating, the ultrafine powder particles having a particle size of 45 μm or less, the dispersant and water contained in the pulverized porous iron ore 1 are homogenized in the sintering raw material, In order to increase the dispersibility of ultrafine powder particles having a particle size of 45 μm or less in moisture during granulation by the granulator 4 and to improve the granulation properties and adhesion of the sintered raw material, A kneader may be provided. In this case, in order to improve the dispersibility of ultrafine particles having a particle diameter of 45 μm or less in water during granulation, it is necessary to add the dispersant together with water at least when mixing with a kneader. Furthermore, when granulating with the granulator 4, it is preferable to add water or water and a dispersing agent in order to improve the effect of the ultrafine particles having a particle diameter of 45 μm or less.

  As the kneader, a Redige mixer and a drum mixer are used. When a drum mixer is used as the granulator 4 and a kneader is provided in front of the granulator 4, the drum mixer can be used exclusively for granulation. In this case, a drum mixer is used as the granulator 4, and a drum mixer is provided as a kneader before the granulator 4, that is, two drum mixers are provided in series, and the previous drum mixer is dedicated for mixing. Of course, it is also possible to use the later drum mixer exclusively for granulation.

  In addition, when many fine iron materials such as fine iron ore for pellets (pellet feed) and ironmaking dust are blended in the sintered raw material, and a sintered raw material with a high content of fine powder particles of 0.5 mm or less is granulated May strengthen granulation by connecting two or more granulators 4 in series. A preferred embodiment in this case will be described later with reference to FIG.

  Moreover, in the present invention, the porous iron ore 1 is a porous iron ore having a fine pore amount measured by a mercury intrusion method of 0.05 cc / g or more, and if it is an iron ore corresponding to this condition, Regardless of the iron ore brand, it can be the object of grinding in the present invention. Examples of the iron ore corresponding to the porous iron ore having the fine pore amount of 0.05 cc / g or more include, for example, Mount Newman (low adjacent block man (hematite ore), H3 in FIG. ), Jandi (Pisolite Ore, P1 in FIG. 10), Robe (Pisolite Ore, P2 in FIG. 10), MAC (Malamanba Ore, M1 in FIG. 10), West Angelus Ore (Malamanba Ore, M2 in FIG. 10), Salgaonka In addition to (goethite ore, G in FIG. 10), high phosphorus Brockman ore (hematite ore), Hamasley ore in which hematite and maramamba ore are blended, and the like.

  In the present invention, the other iron-containing raw material is an iron ore other than the porous iron ore 1 to be pre-ground in the present invention, that is, the amount of fine pores measured by a mercury intrusion method is less than 0.05 cc / g. What consists of 1 type (s) or 2 or more types among a certain iron ore, sintered refining, sintered under sieve powder, and iron-making dust is preferable. Here, the sintered ore and sintered sieving powder are powdered ores that are smaller than a predetermined size among the sintered ores manufactured by the sintering process, and the product sintered ore is a blast furnace. It means powdered sinter collapsed in the process of transporting up to. Moreover, iron-making dust means iron-containing dusts such as steel-making dust and mill scale generated in the iron-making process.

  As another embodiment of the present invention, as shown in FIG. 7, a sieve 6 is arranged in front of the pulverizer 2, and sieved with a 2 to 7 mm sieve before the porous iron ore 1 is crushed. Then, the sieve of the porous iron ore (particle diameter of 2 to 7 mm or more) is pulverized by a pulverizer 2 to obtain a pulverized product having a particle size of 15% or more of fine powder having a particle size of 45 μm or less, and the porous The fine iron ore sieve (particle diameter of 2-7 mm or more) is blended in the other iron-containing raw material, auxiliary raw material, and carbonaceous material 3 as it is. After supplying, mixing, and granulating, sintering can be performed using the sintering machine 5. According to this embodiment, in addition to the reduction of the load on the pulverizer 2, the intermediate particles having a particle size of 0.5 to 1 mm with little contribution in constituting the pseudo particles during granulation are pulverized, Increasing the number of fine particles having a particle size of 45 μm or less is preferable in order to improve the pseudo-particle property and adhesion of the sintering raw material. In the embodiment shown in FIG. 7, the above-mentioned effect can be obtained when sieving with less than 2 sieves. However, when the sieve mesh is less than 2, clogging occurs when sieving, This is not preferable because the yield decreases or the working efficiency decreases. On the other hand, when sieving with a mesh size exceeding 7 mm, the above effect cannot be obtained.

  In the embodiment shown in FIG. 7, when pulverizing the sieve of the porous iron ore (particle diameter of 2 to 7 mm or more), the iron ore having an average particle diameter of 3 mm or less other than the porous iron ore It is also possible to supply auxiliary materials to the pulverizer 2 and pulverize them together. In this embodiment, among the porous iron ore, the iron ore having an average particle size of 3 mm or less other than the porous iron ore, and the auxiliary raw material, the particle size that contributes little to constituting pseudo particles during granulation Is preferable in order to improve the pseudo-particle property and adhesion of the sintered raw material by pulverizing 0.5 to 1 mm of intermediate particles and increasing fine particles having a particle size of 45 μm or less. In addition, as an iron ore with an average particle diameter of 3 mm or less other than the said porous iron ore, the fine iron ore for pellets (pellet feed) is preferable.

  Further, as another embodiment of the present invention, as shown in FIG. 8, the porous iron ore 1 is pulverized by a pulverizer 2 so as to have a particle size containing 15% or more of fine powder having a particle size of 45 μm or less. The material is blended with other iron-containing raw materials other than the porous iron ore 1 and the auxiliary raw material 9 and supplied to the kneader 7 to add water and a dispersing agent so that the water and the dispersing agent are uniform in the sintering raw material. After being mixed, the mixture is supplied to the first-stage granulator 4-1 for primary granulation to obtain a granulated product. Furthermore, the surface of the granulated material is obtained by adding a carbonaceous material or a carbonaceous material and a CaO-containing auxiliary raw material 8 to the obtained granulated material, and supplying it to the second-stage granulator 4-2 for secondary granulation. A granulated material coated with a carbon material or a carbon material and a CaO-containing auxiliary material is manufactured and sintered with a sintering machine 3.

  In addition, although a Redige mixer and a drum mixer are used as the kneader 7, the Redige mixer is more preferable. Moreover, any of a drum mixer, a disk pelletizer, or a pan pelletizer can be used as the granulator 4-1 and the granulator 4-2.

  In this embodiment, a pulverized product made of porous iron ore 1 is blended with other iron-containing raw materials and auxiliary raw materials having a high fine powder content such as fine iron ore for pellets (pellet feed) and iron-making dust, and granulated. This is an effective method. According to the present invention, ultrafine powder having a particle size of 45 μm or less, which is highly dispersible in moisture contained in the pulverized product made of porous iron ore 1, is utilized, and the ultrafine powder is uniformly dispersed in moisture. In this embodiment, the cohesive force of moisture is enhanced by the above, so that even if there are many fine powders having a particle size of 0.5 mm or less in the sintered raw material, the effect of improving the pseudo-granulating property and adhesion of the sintered raw material can be obtained. Thus, the following problems can be solved when the granulated product of the sintering raw material having a high fine powder content is satisfactorily sintered.

  That is, a sintered raw material having a high fine powder content comprising the porous iron ore 1, other iron-containing raw materials other than the porous iron ore 1, and the auxiliary raw material 9 is supplied to the kneader 7. Since the granulated product obtained by primary granulation with the granulator 4-1 is a granulated product having a relatively high density, when it is baked as it is with an ordinary sintering machine 5, Oxygen diffusion into the water is hindered, and combustion of internal carbon materials may be delayed. In order to solve this problem, in this embodiment, after the primary granulation by the first-stage granulator 4-1, the carbon material 8 is further added and the second-stage granulator 4-2 is used. By performing secondary granulation, a granulated product in which the carbon material 8 is sheathed on the surface layer is formed and sintered by the sintering machine 5. Thereby, at the time of sintering, the combustibility of the carbonaceous material on the surface of the granulated material is improved, and the inside of the granulated material is fired satisfactorily by the transfer of combustion heat from the surface layer.

In addition, when both the carbonaceous material and the CaO-containing auxiliary raw material 8 are packaged on the surface of the granulated product, a calcium ferrite melt having excellent reducibility is produced along with the combustion of the carbonized material on the surface of the granulated product. Is promoted, and a sintered ore in which the granulated material is bonded by this bonded phase is produced. The sintered ore in which the granulated material is fixed with a calcium ferrite binder phase becomes a sintered ore with good reducibility when used in a blast furnace. As the CaO-containing auxiliary material, limestone, slaked lime, or quicklime can be used.
In the embodiment shown in FIG. 8, when the pulverized product of the porous iron ore 1, the other iron-containing raw material, and the auxiliary raw material 9 are mixed by the kneader 7, During the primary granulation by the granulator 4-1 and the secondary granulation by the granulator 4-2, the ultrafine powder particles having a particle size of 45 μm or less, the dispersant and water are homogenized in the sintering raw material. In addition, it is necessary to increase the dispersibility of ultrafine particles having a particle diameter of 45 μm or less in water, and to add the dispersant together with water at least when mixing with the kneader 7.

  Furthermore, in either or both of the primary granulation by the granulator 4-1 and the secondary granulation by the granulator 4-2, adding water or water and a dispersing agent This is preferable in order to improve the effect of ultrafine powder particles having a diameter of 45 μm or less.

  Moreover, in the said embodiment, when mixing by the said kneading | mixing 7, the said iron ore 1 and other iron containing raw materials other than a porous iron ore, and the auxiliary raw material 9 are set to carbonaceous material and CaO containing auxiliary raw material. It is also possible to add one kind or two kinds 10. As a result, although less effective than the addition of the surface layer of the granulated product, each granulated product is produced by burning the carbonaceous material inside the granulated product and / or generating a calcium ferrite binder phase inside the granulated product. The strength of is improved.

  In the embodiment shown in FIG. 8, preferred types and addition amounts of the dispersant are as described in the embodiment shown in FIG.

  The effects of the present invention will be described below with reference to examples. Needless to say, the present invention is not limited to only the examples described below, and the effect can be obtained even under the following conditions as long as the object and technical idea of the present invention described above are not violated.

  An example was performed by the manufacturing process of the sintered ore shown in FIGS. 6 and 8, and a comparative example was performed by the manufacturing process of the sintered ore shown in FIG.

  Table 3 shows the composition of iron-containing raw materials other than the porous iron ore used in Examples and Comparative Examples, auxiliary raw materials, and carbonaceous materials. In Examples and Comparative Examples, porous iron ore is crushed as it is or under the pulverization conditions shown in Table 1, and this pulverized product is blended in a blending ratio with respect to the total amount of other iron-containing raw materials and auxiliary raw materials shown in Table 3. Then, under the conditions shown in Table 1, only the addition of water, or a dispersant was added together with the addition of water, and granulated. The obtained granulated product is measured and evaluated for adhesion and pseudo-granulating property (GI value), and further, the granulated product is sintered with a sintering machine, and the productivity at this time is also evaluated. It was. In addition, the blending ratio of the pulverized raw material shown in Table 2 is expressed as a ratio (mass%) to the total amount of the sintered raw material other than the pulverized raw material and the pulverized raw material shown in Table 3. Moreover, the addition amount of a dispersing agent and water | moisture content shown in Table 2 is a ratio (mass%) with respect to the total amount of the pulverized raw material mixed and granulated and the other sintered raw materials shown in Table 3. In the dispersant, CMC represents carboxymethyl cellulose, and PA represents sodium polyacrylate.

  In addition, in Example 10 and Example 11 of Table 2, the addition amount of a water | moisture content and a dispersing agent is each process of mixing (7), primary granulation (4-1), and secondary granulation (4-2), respectively. The total addition amount added in is shown as a ratio to the total amount of the pulverized product, other iron-containing raw materials, and auxiliary raw materials.

  Sintering was performed using a sintering machine having a sintering area of 400 m 2 and a pallet width of 5 m, a layer thickness of 600 mm, a coke blending amount of 3.7%, and a suction negative pressure of 14.2 MPa.

  Table 1 shows the adhesion force and pseudo-granulating property (GI value) of the granulated product obtained by granulating the sintering raw material, and the evaluation results of the sintering production rate.

  The adhesion of the granulated product obtained by granulating the sintered raw material is measured by the tensile fracture method, and the pseudo-granulating property (GI value) of the granulated product is GI (%) = (before granulation) The ratio of the raw material of 0.25 mm or less of-the ratio of the raw material of 0.25 mm or less after granulation / (the ratio of the raw material of 0.25 mm or less before granulation) x 100.

As can be seen from Table 2, in the case of Comparative Example 1 in which the porous iron ore was granulated without being pulverized by the conventional method shown in FIG. 9, the adhesion of the granulated product was 21 (cm 2 / g), The GI index was as low as 78.8 (%), and the productivity of sintering was as low as 35.0.
On the other hand, in Examples 1 to 11 in which the porous iron ore was pulverized and granulated within the scope of the embodiment of the present invention shown in FIG. 6 or FIG. More than (cm2 / g), the GI index is as high as 80% or more, and by granulating the porous iron ore that deteriorates the granulation property of the sintering raw material, the granulation property of the sintering raw material is greatly improved. It was. In addition, the granulation property of the sintering raw material is improved with a relatively small amount of moisture, and the collapse in the moisture condensing zone in the sintering machine is suppressed, so that the sintering productivity is 37 (t / d / m 2). As above, good results were obtained.

The cross-sectional structure | tissue photograph at the time of carrying out a microscope observation about each before (FIG. 1 (a)) and after grinding | pulverization (FIG.1 (b)) of the maramamba ore which is the porous iron ore of this invention is shown. The cross-sectional structure | tissue photograph at the time of carrying out the microscope observation at high magnification about the martite structure | tissue in the maramamba ore before grinding | pulverization (FIG. 2 (a)) of FIG. 1 of this invention and after grinding | pulverization (FIG. 2 (a)) is shown. The surface of the granulated material obtained by adding water after adding the water after pulverizing the maramamba ore which is the porous iron ore of the present invention (FIG. 3 (a)) The micrograph at the time of observing a microscope is shown. It is the figure which showed the relationship between the additional water content at the time of granulating the maramamba ore which is the porous iron ore of this invention, the fine powder content of the particle size of 45 micrometers or less after a grinding | pulverization, and the adhesive force of a granulated material. The relationship between the amount of added water when granulating the maramamba ore, which is the porous iron ore of the present invention, the content of fine powder with a particle size of 45 μm or less after pulverization, and the GI value (pseudo-particle conversion index) of the granulated product is shown. It is a figure. It is explanatory drawing which shows the manufacturing process of the sintered ore using the sintering raw material of this invention. It is explanatory drawing which shows the manufacturing process of the sintered ore using the sieve in the case of manufacture of the sintering raw material of this invention. It is explanatory drawing which shows the manufacturing process of the sintered ore using the mixer and two granulators in the case of manufacture of the sintering raw material of this invention. It is a figure which shows the manufacturing process of the sintered ore using the conventional sintering raw material. It is the figure which showed the relationship between the amount of fine pores and water absorption of various iron ores. It is the figure which showed the relationship between the water absorption of various iron ores and GI value (pseudo-particle-izing index).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Porous iron ore 2 Crusher 3 Other iron-containing raw materials, auxiliary raw materials, and carbon materials 4, 4-1, 4-2 Granulator 5 Sintering machine 6 Sieve 7 Kneading machine 8 Carbon materials or carbon materials CaO-containing auxiliary raw material 9 Other iron-containing raw materials and auxiliary raw materials other than porous iron ore 1 Carbon material and CaO-containing auxiliary raw material 1 type or 2 types

Claims (16)

  In a method for producing a sintered ore in which a sintered raw material comprising iron-containing raw material, auxiliary raw material, and carbonaceous material is charged into a sintering machine and sintered, at least the iron-containing raw material is mixed and produced Before granulating, among the iron ores blended in the iron-containing raw material, at least a porous iron ore having a fine pore volume measured by a mercury intrusion method of 0.05 cc / g or more is contained in the porous iron ore. A method for producing a sintered ore, wherein the fine powder having a particle size of 45 μm or less is pulverized to a particle size containing 15% or more.   The method for producing sintered ore according to claim 1, wherein the porous iron ore is sieved with a 2 to 7 mm sieve before pulverization, and the sieving of the porous iron ore is pulverized.   The method for producing a sintered ore according to claim 1 or 2, wherein the pulverization of the porous iron ore is performed together with an iron ore having an average particle size of 3 mm or less other than the porous iron ore, and an auxiliary material.   The method for producing a sintered ore according to claim 3, wherein the iron ore having an average particle size of 3 mm or less other than the porous iron ore is a fine iron ore for pellets.   The sintering according to any one of claims 1 to 4, wherein the porous iron ore is composed of one or more of maramamba ore, high phosphorus block man ore, pisolite ore, and low adjacent block man. Manufacturing method of ore.   The method for producing a sintered ore according to any one of claims 1 to 5, wherein the mixing and granulation are performed by adding water and mixing and granulating with a drum mixer.   The method for producing a sintered ore according to any one of claims 1 to 5, wherein the mixing and granulation are performed by adding a dispersant together with water and mixing and granulating with a drum mixer.   6. The mixing and granulation are performed by adding a dispersant together with water and mixing with a kneader, and then granulating with any of a drum mixer, a disk pelletizer, or a pan pelletizer. The manufacturing method of the sintered ore in any one of.   The method for producing a sintered ore according to claim 8, wherein water or water and a dispersing agent are added in the granulation.   The mixing and granulation are carried out by adding a dispersant together with water, mixing with a kneader, and performing primary granulation with any of a drum mixer, a disk pelletizer, or a pan pelletizer, and further adding a carbonaceous material to the granulated material. Alternatively, the carbonaceous material and the CaO-containing auxiliary material are added, and the granulated material surface is subjected to secondary granulation by using a drum mixer, a disk pelletizer, or a pan pelletizer, whereby the carbonaceous material or the carbonaceous material and the CaO-containing auxiliary material are added to the surface of the granulated product. The method for producing a sintered ore according to any one of claims 1 to 5, wherein the outer or outer packaging is provided.   The method for producing a sintered ore according to claim 10, wherein water or water and a dispersant are added in either or both of the primary granulation and the secondary granulation.   A method of producing a sintered ore according to any one of claims 8 to 11, wherein a Redige mixer is used as the kneader.   The method for producing a sintered ore according to any one of claims 10 to 12, wherein one or two of carbonaceous materials and CaO-containing auxiliary raw materials are added when mixing with the kneader.   The dispersant includes at least an iron-containing raw material to be mixed and granulated, and is added in a range of 0.001% by mass to 1% by mass with respect to the total amount of the sintered raw material excluding the carbonaceous material. The manufacturing method of the sintered ore in any one of 7-13 characterized by these.   After mixing the dispersing agent and the sintering raw material including at least the iron-containing raw material to be mixed and granulated and excluding the carbonaceous material, the mixed composition is made to be 10 g in a solid content in a 100 ml measuring cylinder. Ion-exchanged water was added to this and added to 100 ml, and the mixture was stirred for 10 seconds. After standing for 10 minutes, the amount of fine particles floating in water was 2% by weight of the solid content of the mixed composition. The amount of the dispersant added to the total amount of the sintered raw material including at least the iron-containing raw material to be mixed and granulated and excluding the carbonaceous material is adjusted as described above. Method for producing sintered ore. The method for producing a sintered ore according to any one of claims 7 to 15, wherein the dispersant is a polymer compound having an acid group and / or a salt thereof.