JP4725230B2 - Method for producing sintered ore - Google Patents

Description

  The present invention relates to a method for producing a sintered ore used as a main raw material for a blast furnace ironmaking method or the like.

Sinter ore, which is the main raw material of a blast furnace, is generally manufactured as follows. First, a raw material ore (pulverized iron ore) is blended with CaO-containing auxiliary materials such as lime powder, SiO _2- containing auxiliary materials such as silica and serpentine, and carbon materials such as coke powder, and an appropriate amount of water is added thereto. Mix and granulate. This granulated compounded raw material (sintered raw material) is filled onto a pallet of a Dwytroid type sintering machine to a predetermined thickness, and after igniting the carbonaceous material on the surface of the packed bed, air is directed downward. The carbonaceous material inside the packed bed is burned while being sucked, and the blended raw material is sintered by the combustion heat to obtain a sintered cake. Then, by pulverizing and sizing the sintered cake, a product sintered ore having a particle size of several mm or more can be obtained.

  In order to perform stable blast furnace operation, high-quality sintered ore is required. In general, the quality of sintered ore is indicated by cold strength, reduced powder index (RDI), reducibility (RI), etc., but the quality of the product sinter ore, which uses these as indicators, It has a great influence on the stability of the lowered state in the furnace, air permeability and liquid permeability in the furnace, ore reduction efficiency, high temperature properties, and the like. For this reason, strict quality control is performed in the manufacturing process of sintered ore. Moreover, in order to reduce the manufacturing cost of a sintered ore, the improvement of the product yield of a sintered ore is calculated | required, and also the efficiency improvement and productivity improvement of a sintered ore production line are calculated | required.

Since Japan does not have iron ore resources in the country, iron ore, which is a raw material for sintered ore, is 100% dependent on imports from overseas. In recent years, iron ore imports account for about 65% of Australian ores, about 20-25% of South American ores, and about 10-15% of Indian ores.
Here, iron ores having a relatively small P (phosphorus, hereinafter the same) content are roughly classified into hematite ore, magnetite ore, limonite ore, and maramamba ore as shown in Table 1 from the constituent minerals. Among these, a structure enlarged photograph of hematite ore, limonite ore and maramamba ore is shown in FIG.

South American ores are mainly hematite ores with low gangue components and high Fe grade, and some magnetite ores have been used as high-quality raw materials for sintered ore. However, there is a problem that the transportation cost is high because the production area is a long distance.
Although Indian ores have high gangue content such as SiO ₂ compared to South American ores, high-quality hematite ores and hematite ores containing about 4 to 5 mass% of crystal water are representative ores. There is one. However, compared to South America and Australia, the amount of reserves is small, infrastructure development for mining and transportation / shipping to the port is delayed, and there are restrictions on the shipping time due to the influence of monsoon, etc. There are problems, and the import ratio is sluggish.

  Australian ore, on the other hand, has been actively invested by mining companies, and its production volume has grown significantly since the 1980s, making it the main source of iron ore supply. However, the high-quality hematite ore that has been used favorably in Japan's steel industry has been rapidly depleting 30 years after its development, and the limonite ore that has been developed since the mid-1990s. However, production has reached a peak. On the other hand, many newly developed mines in recent years produce ores mainly composed of maramamba ore.

Here, the Mara Mamba ore is a general term for iron ores produced from the Mara Mamba deposit in Australia, and is generally a goethite (Fe ₂ O ₃ .H ₂ O) and martite (Fe ₂ O ₃ having a magnetite structure). Is an ore with a high crystal water content compared to hematite ore. By brand name, West Angelus ore and MAC ore are typical iron ores. A typical example of limonite ore is pisolite ore. This pisolite ore generally has an internal structure in which the gap between fish egg-like hematite (Fe ₂ O ₃ ) is filled with goethite (Fe ₂ O ₃ .H ₂ O), and is further more than maramanba ore. It is an ore with a high crystal water content. In the brand name, lobe river ore and yandi coujina ore are typical iron ores.

  In addition, iron ores generally containing 0.10 mass% or more of P with respect to iron ores having a P content of less than 0.10 mass% (usually 0.06 mass% or less) like the various iron ores described above. Is called high phosphate ore. The use of such iron ore with a high P content as a blast furnace raw material increases the P concentration of the hot metal produced and increases the load of dephosphorization treatment in the steelmaking process. Was not. However, since the supply amount of high-quality iron ore is decreasing as described above, it is being studied to add a considerable amount of this high phosphate ore as a sintering raw material.

Conventionally used hematite ore has good sinterability. Sintered ore is adjusted in quality and production so that the basicity (CaO / SiO ₂ ) is adjusted to 1.7 or more by adding CaO source auxiliary material. Both sex and yield are good.
On the other hand, limonite ore among Australian ores usually contains about 9 to 11 mass% of crystal water, and there are few fine parts and the particle size is coarse, but as shown in the structure photograph of FIG. There are many rough air holes inside. For this reason, when the limonite ore is baked, the crystal water in the ore is released to make it more porous and cracks are derived. In addition, when a CaO-based melt formed by the reaction of the CaO source auxiliary material and iron ore in the sintering process intrudes into the relatively coarse pores from which crystal water has been removed, it rapidly assimilates and causes excessive melting. . Therefore, when a large amount of limonite ore is blended, not only does the strength of the sintered ore decrease, but a portion that grows in the form of a rock plate by generating excess melt in the sintering bed is generated, and this overmelting occurs. A significant unevenness occurs in ventilation between the part and the other part, and an unfired part is left below the overmelted rock-like part, resulting in a significant reduction in yield.

  On the other hand, maramamba ore, which is newly developed as an Australian ore and is expected to increase in use in the future, generally has a crystal water content of about 4 to 6 mass%, and it has less rough atmospheric pores than limonite ore. Therefore, excessive melting during firing is alleviated. However, since fine pores exist in the entire structure, it is easy to absorb the melt, and the absorbed melt assimilates the ore from the periphery, and when the Fe concentration in the melt increases, the viscosity rapidly increases and the internal Firing is completed with the pores left behind. For this reason, the melt does not sufficiently spread to adjacent ores, and the maramamba ore portion becomes a sintered ore with fine pores remaining, so that the strength is lowered and the yield is also lowered. Furthermore, because Mara Mamba ore has a fine particle size, when used in large quantities, the particle size after raw material granulation does not increase in the raw material processing step of sintering, and the bed of the bed charged on the sintering machine pallet does not increase. Air permeability will deteriorate and productivity will fall.

As described above, while high-quality hematite ore and magnetite ore tend to be depleted, large-scale use of limonite ore and maramamba ore has a major problem that the quality and productivity of the resulting sintered ore are reduced. . For this reason, high-quality sintered ore (for example, JIS
Currently, it is becoming difficult to manufacture a high production rate (for example, 1.5 t / h / m ² or more) at a low cost with a rotational strength of M 8712: 66% or more.
In addition, with respect to high phosphate ore, when a considerable amount of this is used, there is a problem that the P concentration in the hot metal is increased and the load of dephosphorization treatment is increased. Therefore, there has been little research on the influence on the quality, productivity and product yield of sintered ore when a considerable amount is mixed in the sintering raw material. Therefore, when the present inventors investigated and examined the influence of the high phosphate ore blending on the quality of the sintered ore, etc., the production rate of the sintered ore tends to decrease as the blending amount of the high phosphate ore increases. It has been found.

  Therefore, an object of the present invention is to produce a sintered ore that can produce a high-quality sintered ore at a high production rate and yield at a low cost under the above-mentioned supply situation of raw iron ore. Is to provide.

  The inventors of the present invention have studied the optimum blending conditions for solving the above problems on the premise that the above-described plural types of iron ores are blended simultaneously in the sintering raw material. As a result, hematite ore, magnetite ore, limonite ore, maramamba ore, and high phosphorus ore are blended at a blending ratio that takes into consideration the influence and interaction of their properties on the sintering process, resulting in high quality. It has been found that it is possible to produce a large sintered ore with high productivity and yield at a low cost.

The present invention has been made on the basis of the above findings, and the gist thereof is as follows.
[1] The raw ore to be blended has an iron ore A having a crystallization water content of 9.0 mass% or more, a P content of 0.10 mass% or more, and an Al ₂ O ₃ content of 2.0 mass% or more. Iron ore B, iron ore C having a crystal water content of 4.0 mass% or more and less than 9.0 mass%, and iron ore D having a crystal water content of less than 4.0 mass% (provided that iron ore A, iron ore C and iron ore D are sintered raw materials composed of a P content of 0.10 mass% or more and an Al ₂ O ₃ content of 2.0 mass% or more).
The ratio of the iron ore D in the raw material ore is 20 to 50 mass%, and the mixing ratio of the iron ore A, iron ore B and iron ore C (however, the mixing ratio when iron ore A + B + C = 100 mass%) ), Point a (iron ore A: 60 mass%, iron ore B: 0 mass%, iron ore C: 40 mass%), point b (iron ore A: 60 mass%, iron ore B: 30 mass%) , Iron ore C: 10 mass%), point c (iron ore A: 20 mass%, iron ore B: 30 mass%, iron ore C: 50 mass%) and point d (iron ore A: 50 mass%, iron ore B: 0 mass%) , Iron ore C: 50 mass%), a sintered ore production method characterized by producing sintered ore from a sintering raw material within a range surrounded by iron ore B> 0 mass%.

[2] In the production method of [1], the mixing ratio of the iron ore A, iron ore B, and iron ore C (however, the mixing ratio when iron ore A + B + C = 100 mass%) is shown in FIG. Point e (Iron Ore A: 60 mass%, Iron Ore B: 10 mass%, Iron Ore C: 30 mass%), Point f (Iron Ore A: 60 mass%, Iron Ore B: 20 mass%, Iron Ore C: 20 mass%), Point g (iron ore A: 50 mass%, iron ore B: 30 mass%, iron ore C: 20 mass%), point c (iron ore A: 20 mass%, iron ore B: 30 mass%, iron ore C: 50 mass%) and A sintered ore produced from a sintered raw material within a range surrounded by a point h (iron ore A: 40 mass%, iron ore B: 10 mass%, iron ore C: 50 mass%) Production method.
[3] The method for producing sintered ore according to [1] or [2], wherein the amount of raw ore in the sintered raw material is 60 mass% or more.

  ADVANTAGE OF THE INVENTION According to this invention, the problem by using a high crystal water ore, ore with many fine powder ratios, etc. can be eliminated, and a high quality sintered ore can be manufactured with a high production rate and a yield at low cost.

In order to produce a high-quality sintered ore at a high production rate, the crystal water content and particle size of the raw ore to be mixed with the sintering raw material are important factors, but limonite ore, hematite ore / magnetite ore, maramanba The ore can be distinguished by the crystal water content as follows.
(1)
Iron ore with crystallization water content of 9.0 mass% or more A = limonite ore
(2)
Iron ore with crystal water content of 4.0 mass% or more and less than 9.0 mass% C = Malamanba ore
(3)
Iron ore with crystal water content of less than 4.0 mass% D = hematite ore or magnetite ore The usual particle size of these iron ores is the weight average diameter of limonite ore of 3.0 mm or more, hematite ore, Magnetite ore is about 2.2 mm or more, and Maramamba ore is about 1.8 mm.

On the other hand, high phosphorus ore has a P content that is prominently higher than that of other ores. Generally, the P content of other ores is 0.06 mass% or less, while P content is 0.10 mass% or more. . In addition, the high phosphate ore has a relatively high Al ₂ O ₃ content of 2.0 mass% or more, and the crystal water content is lower than that of limonite ore, but is twice or more that of hematite ore. In addition, regarding the particle size composition of the high phosphate ore, the proportion of fine powder having a particle size of 0.25 mm or less is as high as that of Maramanba ore, and the weight average diameter is 2.0 mm or less and is as fine as Maramanba ore. It is a feature. From the characteristics of the so-called high phosphate ore as described above, the high phosphate ore is distinguished from other ores (the iron ores A, C, and D mentioned above) by the P content and the Al ₂ O ₃ content. Therefore, in the present invention, an ore having a P content of 0.10 mass% or more and an Al ₂ O ₃ content of 2.0 mass% or more is defined as “high phosphorus ore”, and this is defined as iron ore B. And
Table 2 shows the typical chemical composition and LOI (mass loss ratio after heating highly correlated with crystal water content) for high phosphate ore, limonite ore, hematite ore, and maramamba ore. Table 3 shows (particle size distribution, arithmetic mean diameter).

In the method for producing sintered ore according to the present invention, the raw material ore in the sintered raw material is composed of the four types of iron ores A, B, C, and D, and the blending ratio thereof is as follows.
First, the ratio of the iron ore D (hematite ore and / or magnetite ore) in the raw material ore is set to 20 to 50 mass%. As mentioned earlier, iron ore D tends to be depleted and its output is decreasing year by year. Also, it is disadvantageous to use a large amount in terms of cost, but it is a high quality iron ore with high Fe grade. It is indispensable from the aspect of ensuring quality and productivity of sintered ore.

  Here, the supply ratio of iron ore from major production areas (supply ratio to Japan) is about 65% for Australian ore, about 20-25% for South American ore, and about 10-15% for Indian ore. It is. Further, almost all of South American ores and Indian ores are iron ore D, while in Australian ores, the ratio of iron ore D is about 25%. Therefore, the ratio of iron ore D in all iron ores supplied from the main production areas is: Australian ore (about 65% x 0.25) + South American ore (about 20-25%) + Indian ore (about 10-15%) = about 46-56%, that is, about 50%.

  Therefore, mix | blending the iron ore D exceeding 50 mass% of all the raw material ores will increase the manufacturing cost of a sintered ore and is contrary to the objective of this invention. In other words, increasing the blending ratio of expensive iron ore D, which is high in quality compared to other ores, and depleting, itself causes an increase in manufacturing cost and also from the supply situation of iron ore from the current production area. In order to increase the use ratio of iron ore D exceeding 50 mass% of the total raw ore, the only way to increase the production of South American ore (the most expensive iron ore D by production area) is the cost. Will increase significantly.

  On the other hand, when there is too little iron ore D, it becomes difficult to ensure the quality and productivity of the sintered ore. That is, when the blending ratio of iron ore D, which has been suitably used as a raw material for sintering and has a small amount of water of crystallization to obtain a dense sintered structure, is less than 20 mass%, the water of crystallization is removed by firing. Since the blending ratio of iron ores A, B, and C, which tend to become porous, exceeds 80 mass%, it becomes difficult to maintain the strength of the sintered ore (and thus maintain the production rate and yield). .

  Furthermore, about the compounding ratio (ratio of each iron ore in iron ore A + B + C) of iron ore A, B, and C, the point a (iron ore A: 60 mass%, iron ore B: 0 mass%, shown in FIG. 1) Iron ore C: 40 mass%), point b (iron ore A: 60 mass%, iron ore B: 30 mass%, iron ore C: 10 mass%), point c (iron ore A: 20 mass%, iron ore B: 30 mass%) , Iron ore C: 50 mass%) and point d (iron ore A: 50 mass%, iron ore B: 0 mass%, iron ore C: 50 mass%) (provided that iron ore B> 0 mass%) .

The limit line A in FIG. 1 defines the blending limit amount of iron ore A (limonite ore). When iron ore A is blended beyond this limit line i (60 mass% in iron ore A + B + C), sintering is performed. The quality and productivity of the ore is reduced.
That is, since iron ore A is inexpensive, it is advantageous in terms of cost to use a large amount of iron ore A, but it is disadvantageous in terms of quality and productivity because it is a high crystal water ore. Iron ore A contains a large amount of goethite (Fe ₂ O ₃ .H ₂ O) and becomes porous when crystal water is dehydrated at 300 to 500 ° C. to form cracks and pores. When a CaO—Fe ₂ O ₃ melt is generated at a temperature of about 1200 ° C. during the firing process, the melt enters macro pores and cracks and closes the voids, so that the air permeability of the sintered bed is increased. It deteriorates and productivity decreases. On the other hand, since the penetration rate of the melt into the pores and cracks is slow, the sintered ore has a structure containing a large amount of pores, and the strength and yield are also reduced.

  In order to suppress the above phenomenon due to the iron ore A, it is necessary that the iron ore A is charged in a dispersed manner on the sintering bed. For this purpose, it is necessary to coordinate pseudo particles mainly composed of other iron ores (one or more of iron ores B, C, and D) around the pseudo particles mainly composed of iron ore A in the raw material packed bed. In order to obtain a state in which the pseudo particles mainly composed of iron ore A are appropriately surrounded by pseudo particles mainly composed of iron ore and the like, the pseudo particles mainly composed of iron ore A are set to 1, and at least the pseudo particles mainly composed of iron ore and the like are simulated. One or more particles are considered necessary. Here, since the ratio of the iron ore D in the raw material ore is 20 to 50 mass%, if the ratio of the iron ore A in the iron ore A + B + C is 60 mass% or less, the ratio of the pseudo particles is almost satisfied. Will be. In addition, it is considered that it is more preferable if the number of pseudo-particles mainly composed of iron ore A is 1.5 or more, but the ratio of iron ore A in iron ore A + B + C is 50 mass. % Or less, the ratio of such pseudo particles is almost satisfied, and therefore the ratio of iron ore A in iron ore A + B + C is more preferably 50 mass% or less (limit of FIG. 1). Line A ').

  Further, it is considered that it is more preferable that the number of pseudo particles mainly composed of iron ore is about 3 to 4 with respect to the number of pseudo particles mainly composed of iron ore A, and the ratio of the raw material ore in the sintered raw material Is preferably about 60 to 80 mass%. Therefore, if the ratio of iron ore A in iron ore A + B + C is 60 mass% or less, preferably 50 mass% or less, the ratio of iron ore A in the sintered raw material is about 30 mass% or less, The ratio will be satisfied.

The limit line B in FIG. 1 defines the mixing limit amount of iron ore B (high phosphate ore). When iron ore B is mixed beyond the limit line B (30 mass% in iron ore A + B + C), Since the P concentration in the steel becomes excessive, the load of dephosphorization treatment increases (→ increase in steelmaking cost), and the problem caused by the particle size becomes obvious together with iron ore C described later.
Iron ore B is an ore produced from the hematite ore belt, but the P content is about 2 to 3 times that of other ores, and the crystal water content and particle size are close to those of iron ore C (maramanba ore). A large proportion of fine ore. Therefore, when such iron ore B is used in a large amount, the P concentration in the hot metal increases, leading to a significant increase in the dephosphorization cost in the steel making process. Moreover, since it mix | blends with the iron ore C where the ratio of fine powder is also large, when iron ore B is used in large quantities, the problem resulting from a fine powder part, ie, the fall of productivity as mentioned later regarding iron ore C, becomes obvious. From the above points, the blending limit amount of iron ore B is 30 mass%.

The limit line C in FIG. 1 defines the blending limit amount of iron ore C (maramanba ore). When iron ore C is blended exceeding the limit line c (50 mass% in iron ore A + B + C), Along with B, problems due to the particle size of iron ore C become obvious.
Since iron ore C is inexpensive, its use in large quantities is advantageous in terms of cost, but as with iron ore B, the proportion of fine powder is large. In ordinary sintering operations, it is known that fine ore with a particle size of 0.25 mm or less inhibits the air permeability of the sintered bed, and removes such adverse effects of fine ore with a particle size of 0.25 mm or less. Therefore, by granulating the sintered raw material using quick lime or slaked lime as a binder, the size of the raw material particles charged in the sintering machine is set to 3 to 6 mm in weight average diameter. Generally, in granulation of sintered raw materials, the amount of binder added is adjusted in accordance with the content of fine ore with a particle size of 0.25 mm or less in the raw ore. As shown in FIG. In the region where the amount is small, it is proportional to the amount added, but when the amount added is increased to a certain degree (about 2.5 mass% or more), the effect becomes saturated. Therefore, there is a limit to the blending ratio of iron ore C with a large amount of fine ore, and in consideration of blending iron ore B with a large proportion of fine ore like iron ore C, as described below, The limit is about 50 mass% defined by C.

In general, the proportion of fine ore having a particle size of 0.25 mm or less is about 40 mass% for iron ore C, about 5 to 12 mass% for iron ore A, about 20 to 30 mass% for iron ore D, and about 20 to 30 mass% for iron ore B. Although it is about 30 mass%, as shown in FIG. 5, when the proportion of fine-grained ore having a particle size of 0.25 mm or less in the raw ore exceeds about 35 mass%, it adversely affects the sintering, and the production rate seems to decrease. become. And since the ratio of the iron ore B is 30 mass% or less as mentioned above, if the ratio of the iron ore C is 50 mass% or less, the ratio of the fine ore with a particle size of 0.25 mm or less becomes about 35 mass% or less, The impact on productivity is small.
From the above results, in the present invention, the mixing ratio of the iron ores A, B, and C in the raw ore is within the range defined by the limit line loha in FIG. 1 (however, iron ore B> 0 mass%). That is, it is defined as within a range surrounded by point a, point b, point c and point d (however, iron ore B> 0 mass%).

  Furthermore, in the more preferable production method of the present invention, the blending ratio of the iron ores A, B, and C in the raw ore (the ratio of each iron ore in the iron ore A + B + C) is shown in FIG. Iron Ore A: 60 mass%, Iron Ore B: 10 mass%, Iron Ore C: 30 mass%), Point f (Iron Ore A: 60 mass%, Iron Ore B: 20 mass%, Iron Ore C: 20 mass%), Point g ( Iron Ore A: 50 mass%, Iron Ore B: 30 mass%, Iron Ore C: 20 mass%), Point c (Iron Ore A: 20 mass%, Iron Ore B: 30 mass%, Iron Ore C: 50 mass%) and Point h ( Iron ore A: 40 mass%, iron ore B: 10 mass%, iron ore C: 50 mass%).

Here, the reason why the limit lines A, B, and C in FIG. 2 are defined is as described above. Further, the limit line D prescribes the lower limit of the amount of iron ore C (Malamanba ore), and the limit line H prescribes the lower limit of the amount of iron ore B (high phosphorus ore). . By blending iron ores C and B so as not to fall below these limit line D and limit line E respectively, iron ore C, which is cheap but has a large amount of fine ore, is likely to cause the above-mentioned problems. Produces high-quality sintered ore at a lower cost and higher production rate while actively blending iron ore B that is prone to the above-mentioned problems due to its high P content and high amount of fine ore. can do.
Therefore, in the present invention, the mixing ratio of the iron ores A, B, and C in the raw ore is within the range defined by the limit line knee-lo-haho in FIG. It is preferable to be within a range surrounded by f, point g, point c, and point h.

  In the method for producing sintered ore of the present invention, in order to sufficiently secure the effect of the above-described regulation of the mixing ratio of iron ores A, B, C and D, the amount of raw ore in the sintered raw material (iron ore) Stone A + B + C + D) is preferably 60 mass% or more. The blending amount of this raw material ore is a general range in the current sintering operation, but if the blending amount of the raw material ore (iron ore A + B + C + D) is less than 60 mass%, the influence on the sinterability by other raw materials will be affected. Since it becomes apparent, it is difficult to obtain the effect of the present invention.

In the present invention, the raw material ores to be blended in the sintered raw material are four types of iron ores A, B, C, and D. The raw material ore contains component adjusting auxiliary materials (for example, CaO-containing auxiliary material, SiO ₂ -containing). Auxiliary raw materials, etc.), granulation aids (for example, quick lime, etc.), steel mill recovered powder (mainly iron sources such as dust), carbonaceous materials (coke powder, anthracite, etc.), sintered ore sieving powder, etc. Then, a sintering raw material is used, and an appropriate amount of water is added to the sintering raw material and mixed and granulated. This granulated compounded raw material (sintered raw material) is filled onto a pallet of a Dwytroid type sintering machine to a predetermined thickness, and after igniting the carbonaceous material on the surface of the packed bed, air is directed downward. The carbonaceous material inside the packed bed is burned while being sucked, and the blended raw material is sintered by the combustion heat to obtain a sintered cake. Then, by pulverizing and sizing the sintered cake, a product sintered ore having a particle size of several mm or more can be obtained.

As raw materials for sintering (mixed raw materials), raw materials ore (pulverized ore) and other raw materials in the ratios shown in Tables 4 and 5 (outside the ratio of “mixed raw materials” in Tables 4 and 5 only the number of powdered coke) Blended so that the total amount is about 50 kg, mixed this raw material for 3 minutes with a drum mixer while adjusting the moisture content to 7%, and then granulated with the same drum mixer for 3 minutes. Pseudo particles were used. The granulated product was charged into a pan test apparatus having a diameter of 300 mm so that the layer thickness was 400 mm, ignited with a burner, and then fired at a constant negative pressure of 10 kPa to produce a sintered ore.
In this test, selection of brands of iron ore A to D and adjustment of the blending amount were performed so that SiO _{2 of the} sintered product ore was 4.7 ± 0.3 mass% and the basicity was 1.9 to 2.0. . In addition, as quicklime, the activity 300-310 ml and the particle size of 1.0 mm or less were used.

Product sinter production rate, tumbler strength (JIS
Table 6 and Table 7 show the product yield (+10 mm%) after dropping once from a height of 2 m) and the rotational strength according to M 8712). Moreover, in the graph of FIG. 6, the ore mixing | blending of each Example was plotted.
Although the said Example made the hematite ore compounding rate in all iron ores constant about 20 mass%, when increasing the hematite ore compounding rate with 30 mass%, 40 mass%, and 50 mass%, FIG. Improvements in productivity and quality were observed at each point plotted in. However, the unit price of iron ore increased significantly.

Drawing which shows the range of the compounding ratio of iron ore A, B, C prescribed | regulated by this invention Drawing which shows the more limited range of the compounding ratio of iron ore A, B, C prescribed | regulated by this invention Photomicrographs of hematite ore, limonite ore and maramamba ore A graph showing the relationship between the amount of quicklime added to the sintering raw material and the production rate of sintered ore The graph which shows the relationship between the ratio of the fine ore with a particle size of 0.25 mm or less in the raw material ore mix | blended with the sintering raw material, and the production rate of a sintered ore Drawing which shows the mixture ratio of iron ore A, B, C in each Example

Claims (3)

The raw material ore to be blended is an iron ore A having a crystallization water content of 9.0 mass% or more, a P (phosphorus) content of 0.10 mass% or more, and an Al ₂ O ₃ content of 2.0 mass% or more. Iron ore B, iron ore C having a crystal water content of 4.0 mass% or more and less than 9.0 mass%, and iron ore D having a crystal water content of less than 4.0 mass% (provided that iron ore A, iron ore C and iron ore D are sintered raw materials composed of a P (phosphorus) content of 0.10 mass% or more and an Al ₂ O ₃ content of 2.0 mass% or more). ,
The ratio of the iron ore D in the raw material ore is 20 to 50 mass%, and the mixing ratio of the iron ore A, iron ore B and iron ore C (however, the mixing ratio when iron ore A + B + C = 100 mass%) ), Point a (iron ore A: 60 mass%, iron ore B: 0 mass%, iron ore C: 40 mass%), point b (iron ore A: 60 mass%, iron ore B: 30 mass%) , Iron ore C: 10 mass%), point c (iron ore A: 20 mass%, iron ore B: 30 mass%, iron ore C: 50 mass%) and point d (iron ore A: 50 mass%, iron ore B: 0 mass%) , Iron ore C: 50 mass%), a sintered ore production method characterized by producing sintered ore from a sintering raw material within a range surrounded by iron ore B> 0 mass%.   Point e (iron ore A: 60 mass%, iron ore) shown in FIG. 2 is the blending ratio of iron ore A, iron ore B, and iron ore C (provided that iron ore A + B + C = 100 mass%). B: 10 mass%, iron ore C: 30 mass%), point f (iron ore A: 60 mass%, iron ore B: 20 mass%, iron ore C: 20 mass%), point g (iron ore A: 50 mass%, iron ore) B: 30 mass%, iron ore C: 20 mass%), point c (iron ore A: 20 mass%, iron ore B: 30 mass%, iron ore C: 50 mass%) and point h (iron ore A: 40 mass%, iron ore) B: 10 mass%, iron ore C: 50 mass%) The sintered ore is manufactured from the sintering raw material made into the range enclosed, and the manufacturing method of the sintered ore of Claim 1 characterized by the above-mentioned.   The method for producing a sintered ore according to claim 1 or 2, wherein the amount of raw ore in the sintered raw material is 60 mass% or more.