JP4518895B2 - Raw material evaluation method and blending design method - Google Patents

Description

  The present invention relates to an evaluation method for evaluating the characteristics of various brands of iron ore (sintering raw material) used in the manufacture of sintered ore for blast furnace raw material, and based on the evaluation results, the product yield, productivity, and The present invention relates to a blending design method for designing blending of various brands of iron ore (sintering raw material) for producing sintered ore with excellent quality.

  In general, sintered ore for blast furnace raw materials is mixed with iron ore powder, sieving powder, secondary raw materials (limestone, serpentine, etc.), coke breeze, anthracite, ore, etc., and mixed with a primary mixer and a secondary mixer. Pseudo particles in which fine powder having a particle size of less than 1 mm adheres around a core particle having a particle size of 1 mm or more (the portion where the fine powder adheres are referred to as “attached powder portion”) are granulated, and then the pseudo particles are sintered into a sintering machine. To form a sintered bed, and then igniting a fuel such as powdered coke on the surface of the sintered bed, burning it while ventilating downward and firing the sintered raw material.

  In this firing process, the sintering raw material is heated by the combustion heat of the fuel, and the temperature rises to a maximum of around 1300 ° C., but usually around 1200 ° C., from the adhering powder part of the pseudo particles to the quick lime (CaO) The initial melt begins to form due to the formation of low melting point materials composed of fine iron ore, and then, when the temperature rises further, the initial melt dissolves surrounding fine ore components and increases the amount of melt. Let

  Thereafter, agglomeration proceeds while the melt also reacts with the core particles, and finally, a sintered ore is formed in which the remaining unmelted coarse particles are bonded together by a binder phase.

  In general, the quality, yield, and productivity of sintered ore greatly depend on the properties of iron ore (powder) to be blended with the sintering raw material. The air permeability of the particles has a great influence. For example, if the initial melt resulting from the reaction of iron ore (powder) blended with the sintered raw material with quick lime (CaO generated by thermal decomposition of limestone) is rich in fluidity, agglomeration tends to proceed, Increases the strength and yield of the ore.

  Moreover, when the ratio of the fine part of the iron ore in the sintering raw material is small, or the fine part (fine iron ore with a particle diameter of less than 1 mm) to the core particle of the pseudo particle (coarse iron ore with a particle diameter of 1 mm or more) When the adhesion amount is high, the air permeability in the sintering process is increased, and the productivity of the sintered ore is increased. Therefore, it is particularly important to evaluate the melting characteristics of various types of iron ore (powder) and the aeration characteristics of the pseudo-particles in producing sintered ore excellent in quality and productivity.

  Until now, several methods for evaluating the melting characteristics of iron ore (powder) to be blended in the sintering raw material have been proposed. For example, as a method for relatively evaluating the melting behavior of nuclear ore (coarse iron ore having a particle size of 1 mm or more) in pseudo particles, CaO powder having a particle size of 10 μm or less (reagent) ), Or a sample in which iron ore particles cut into 5 mm squares are placed on a CaO tablet is fired in an electric furnace, and the method for evaluating the assimilation reaction between the iron ore particles and limestone is the present invention. (See, for example, Non-Patent Document 1).

  Moreover, in order to simulate the melt generation behavior in the sintering process closer to actual conditions, the present inventors use adhering powder in the pseudo particles (sub-materials such as fine iron ore having a particle diameter of less than 1 mm, CaO powder). As a method for relatively evaluating the melt generation behavior of the steel, a low melting point material is placed on the molded fine iron ore, and the temperature is raised to 1000 ° C. or higher in the air or in a low oxygen atmosphere, Melt and infiltrate the molten melt into the iron ore powder, and measure one or more of the distance, cross-sectional area and volume permeated by the melt, thereby increasing the melt permeability into the iron ore powder. A method for evaluation was proposed (see, for example, Patent Document 1).

  Moreover, as an evaluation method of iron ore for the same purpose, an ore brand evaluation method in which the bottom area of the tablet after sintering a tablet made of iron ore having a particle size of 2 mm or less and limestone at high temperature is used as the fluidity index of the melt. Has also been proposed (see, for example, Non-Patent Document 2).

  Furthermore, 20% CaO powder was blended with each brand iron ore powder, and the volume shrinkage ratio after firing a sample press-molded into a cylindrical shape was measured, and this volume shrinkage ratio was determined in the sintering reaction of each brand iron ore. A method for managing the blending of each brand ore so that the volume shrinkage ratio is within a predetermined range, specifically 15 to 35%, is disclosed (for example, see Patent Document 2).

  The above iron ore evaluation method is based on the individual melting characteristics of iron ore core particles (coarse iron ore having a particle size of 1 mm or more) or iron ore fine particles (fine iron ore having a particle size of less than 1 mm). It is a method to evaluate.

  However, in the actual sintering operation, the pseudo-particles of the sintering raw material mainly consist of coarse iron ore having a particle size of 1 mm or more as a core particle, and auxiliary materials such as fine iron ore and limestone powder having a particle size of less than 1 mm around it. It has a structure in which a differential part consisting of powder and carbonaceous powder is attached, and the melt behavior of iron ore during the sintering process is different between the core particle and the fine powder part, The melt behavior is greatly affected.

  For example, in the case of iron ore of brands such as Hamasley and Mount Newman produced in Australia, the melt behavior in pseudo particles is greatly different between coarse iron ore having a particle size of 1 mm or more and fine powder portions having a particle size of less than 1 mm. Only an evaluation test with a constant particle size has a problem that the entire melt behavior cannot be evaluated correctly.

  Conventionally, a method has been proposed in which a sintering test is performed in advance for each brand of iron ore, and the characteristics of the sintered ore when the blended raw material is used based on the measurement result of the characteristics of the sintered ore.

For example, when the amount of iron ore of each brand is increased or decreased from the basic amount, the iron ore of each brand is classified into a group that deteriorates the reduced powder index (RDI) of the sintered ore and a group that improves it. Based on the blending index (B.I. = ΣBjW _Bj [Deterioration] / ΣAjW _Aj [Improvement]), there is known a method for estimating reduced powdering (RDI) of sintered ore (for example, Patent Document 3). reference).

  Also, the low-temperature reduced powdering index (RDI) of sintered ore obtained by sintering in advance for each iron ore constituting the raw material for sintering is measured, and the RDI and sintered raw material composition measured in advance for each iron ore are measured. Disclosed is a method for predicting the RDI of sintered ore based on the blending ratio based on the plan, and correcting and controlling the blending ratio of each iron ore so that the RDI of the sintered ore is within the set range based on the predicted RDI (For example, see Patent Document 4).

  However, in any of the above methods, in the blending of various brands of iron ore, after performing a sintering test for each brand of iron ore in advance, only the reduced powder index (RDI) indexed based on the results is used. To evaluate. For this reason, it is not always a satisfactory method for accurately evaluating quality such as cold strength other than the reduced powder index (RDI), product yield, and productivity.

  Therefore, as an evaluation method for improving the above problems, the present inventors divided each type of iron ore into coarse and fine particles, and (1) indexed the characteristics of various types of coarse ore as nuclear characteristic indices, And / or (2) indexing the characteristics of various fine iron ores as a powder characteristic index, and (3) evaluating the sintering characteristics of the raw material for sintering based on the nuclear characteristic index and / or the powder characteristic index. Based on the evaluation results, a method for selecting the iron ore and adjusting the blending amount and rate and designing the blending of the raw materials for sintering was proposed (see, for example, Patent Document 4).

  This method is based on the characteristics of the core particles and differential particles of various brands of iron ore, indexed from the viewpoint of the melt behavior in the sintering process, and the characteristics and steps of the sintered ore obtained through the sintering process. Is to predict the retention.

  As a result, when iron ore (powder) is made into pseudo particles, the melt behavior is different in each sintering process, the characteristics of the core particles and the characteristics of the fine powder part, and further the characteristics due to the interaction between the two, Based on this evaluation result, it became possible to estimate the quality and yield of sintered ore under conditions closer to actual operation than before, and to mix and design various brands of iron ore (powder). .

  However, this method does not take into account the effects of non-uniform firing (uneven burning) on the strength, yield, and productivity of sintered ore, which occurs when the air permeability of the sintering raw material is extremely poor during the sintering process. For this reason, when the air permeability varies depending on the type of iron ore, proper evaluation cannot be performed, and it has not been possible to use it for a compounding design with excellent productivity.

JP 2002-62290 A JP 59-153845 A Japanese Patent Laid-Open No. 61-119626 Japanese Unexamined Patent Publication No. 1-176041 JP 2003-82417 A Iron and Steel, 78 (1992), p. 1013 Iron and Steel, 77 (1990), p. 56

  In view of the current state of the art, the present invention is suitable for sintering productivity of a sintering raw material when granulating and sintering a sintering raw material containing one or more types of iron ore (powder). It aims at providing the evaluation method which can be evaluated accurately.

  In addition, the present invention appropriately adjusts the blending amount and blending ratio of one or more iron ores (powder) to be blended with the sintering raw material based on the above-described sintering productivity evaluation results, An object of the present invention is to provide a blending design method for designing a raw material for sintering having excellent sintering productivity.

  The present inventors have further studied a method for appropriately evaluating the sintering productivity, which is one of the important factors in the sintering operation. As a result, it was found that the sintering productivity can be evaluated with high accuracy by using the permeability index of pseudo particles in addition to the above-mentioned nuclear or powder characteristic index and iron powder index.

  The air permeability index of the pseudo-particle is a factor that determines the progress speed of the sintered layer in the sintering process, and as a result of the examination, fine iron ore with a predetermined mass ratio is used as a core particle with coarse iron ore as a predetermined moisture content. It has been found that the productivity of sintering can be evaluated with high accuracy by indexing the measured value of the air permeability of the pseudo particles adhered and granulated or the average particle size of the iron ore constituting the pseudo particles.

  That is, the present inventor has obtained the following knowledge as a result of intensive studies on a method for evaluating the sintering productivity of a sintering raw material.

  (A) The productivity of sintered ore obtained by mixing and sintering two or more types of iron ore (powder) is an index based on a characteristic value that typifies the reaction state between the core particle of the pseudo particle and the melt. A (nuclear characteristic index), index B (powder characteristic index) based on characteristic values representative of simulated melt formation and reaction state in the adhered powder layer, ratio of crystal water in the blended raw material, and firing A good correlation with the sintering productivity index SPI of the following formula (1) or (2) defined by using an index C (aeration characteristic index) based on the aeration characteristics of pseudo particles representative of the air permeability state in the layered layer. Have sex.

^{SPI = k × A x × B} y × (1-D / 100) × C z ... (1)
SPI = A ^x × B ^y × (1-D / 100) ± nC ^w (2)
A: Nuclear characteristic index,
B: Powder characteristic index D: Crystal water ratio of blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
z, w: contribution ratio of air permeability, 0 <z ≦ 1, 0 <w ≦ 1
n: contribution coefficient of air permeability, 0 <n ≦ 15
k: coefficient

  As a matter of course, the index A, the index B, and the index C can be managed independently.

  This invention is made | formed based on the said knowledge, The summary is as follows.

(1) In an evaluation method for evaluating characteristics of a raw material for sintering containing one or more of various iron ores at a predetermined blending ratio, each of the various iron ores is divided into coarse particles and fine particles,
(1) Indexing the porosity in the fired body of pseudo particles granulated by attaching limestone powder to various coarse iron ores as a nuclear characteristic index, and / or
(2) When the molded low-melting-point material is placed on various types of fine-grained iron ore and fired, the distance, cross-sectional area, and volume of the low-melting-point material melt penetrate into the fine-grained iron ore. Alternatively, melt permeability that is confirmed by measuring two or more is indexed as a powder characteristic index,
(3) Calculate the ratio of water of crystallization in the blended raw material from the blend ratio of ore,
(4) Sotsubutetsu ore was indexed the passing temper by attaching fine iron ore having a predetermined mass ratio to the core particles at a predetermined moisture granulated pseudo particles as breathable quality index,
(5) Sintering characterized in that the sintering productivity of the raw material for sintering is evaluated based on the nuclear characteristic index and / or the powder characteristic index, and further the ratio of water of crystallization in the blended raw material and the aeration characteristic index For evaluating raw materials.

  (2) The raw material for sintering according to (1) above, wherein the coarse iron ore is an iron ore having a particle size of 1 mm or more, and the fine iron ore is an iron ore having a particle size of less than 1 mm. Evaluation method.

( 3 ) The characteristic of the coarse iron ore is a porosity in a fired body of pseudo particles granulated by attaching a mixed powder composed of limestone powder, fine iron ore and coke powder to the coarse iron ore. The method for evaluating a raw material for sintering according to (1) or (2) above.

( 4 ) The characteristic of the fine-grained iron ore is a melt fluidity that is confirmed by measuring the bottom area after firing a mixed powder made of fine iron ore and limestone powder formed into a cylindrical shape. The evaluation method of the raw material for sintering as described in any of (1) to (3) above.

(5) passing temper the iron ore, the evaluation method of the sintering raw material according to any one of the above is characterized in that the average particle size of iron ore in the pseudo particles (1) to (4).

( 6 ) A sintering productivity index SPI defined by the following formula (1) is calculated based on the nuclear characteristic index and / or the powder characteristic index, and further, the ratio of crystal water and the aeration characteristic index, and the sintering productivity is calculated. The method for evaluating a sintering material according to any one of (1) to ( 5 ), wherein the sintering productivity of the material for sintering is evaluated based on an index SPI.

^{SPI = k × A x × B} y × (1-D / 100) × C z ... (1)
A: Nuclear characteristic index B: Powder characteristic index D: Ratio of crystallization water in blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
z: contribution rate of air permeability, 0 <z ≦ 1
k: coefficient

( 7 ) Based on the nuclear characteristic index and / or the powder characteristic index, further, based on the crystal water ratio and the aeration characteristic index, a sintering productivity index SPI defined by the following formula (2) is calculated, and the sintering characteristic index The method for evaluating a sintering material according to any one of (1) to ( 5 ), wherein the sintering productivity of the material for sintering is evaluated based on SPI.

SPI = A ^x × B ^y × (1-D / 100) ± nC ^w (2)
A: Nuclear characteristic index B: Powder characteristic index D: Ratio of crystallization water in blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
n: contribution coefficient of ventilation characteristics, 0 <n ≦ 15
w: contribution rate of air permeability, 0 < w ≦ 1

( 8 ) The method for evaluating a raw material for sintering as described in ( 6 ) or ( 7 ) above, wherein the nuclear characteristic index A is defined by the following formula (1a).

A = Σ (a _i × p _i ) / Σ (p _i ) (1a)
a _i : Nuclear characteristic index of iron ore i
p _i : Mixing ratio of iron ore i having a particle diameter of 1 mm or more (%)

( 9 ) The method for evaluating a raw material for sintering according to any one of ( 6) to (8), wherein the powder characteristic index B is defined by the following formula (1b).

B = Σ (b _i × q _i ) / Σ (q _i ) (1b)
b _i : Powder characteristic index of iron ore i
q _i : Mixing ratio (%) of iron ore i having a particle diameter of less than 1 mm

( 10 ) The method for evaluating a raw material for sintering according to any one of ( 6) to (8), wherein the air permeability characteristic index C is defined by the following formula (1c).

C = Σ (c _i × r _i ) / Σ (r _i ) (1c)
c _i : Aeration characteristic index of iron ore i
r _i : Mixing ratio of iron ore i (%)

( 11 ) In the blending design method for designing a raw material for sintering containing one or more of various iron ores at a predetermined blending ratio, each of the various iron ores is divided into coarse and fine grains,
(1) Indexing the porosity in the fired body of pseudo particles granulated by attaching limestone powder to various coarse iron ores as a nuclear characteristic index, and / or
(2) When the molded low-melting-point material is placed on various types of fine-grained iron ore and fired, the distance, cross-sectional area, and volume of the low-melting-point material melt penetrate into the fine-grained iron ore. Alternatively, melt permeability that is confirmed by measuring two or more is indexed as a powder characteristic index,
(3) Calculate the ratio of water of crystallization in the blended raw material from the blend ratio of ore,
(4) Sotsubutetsu ore was indexed the passing temper by attaching fine iron ore having a predetermined mass ratio to the core particles at a predetermined moisture granulated pseudo particles as breathable quality index,
(5) Calculate the sintering productivity index SPI defined by the following formula (1) based on the nuclear characteristic index and / or the powder characteristic index, and further, the ratio of water of crystallization in the blended raw material and the aeration characteristic index,
(6) Based on the sintering productivity index SPI, the sintering productivity of the sintering raw material is evaluated,
(7) A method for blending and designing a raw material for sintering, wherein the blending ratio of iron ore to be blended with the raw material for sintering is adjusted based on the evaluation result.

^{SPI = k × A x × B} y × (1-D / 100) × C z ... (1)
A: the number of nuclear properties finger
B: Powder characteristic index D: Crystal water ratio of blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
z: contribution rate of air permeability, 0 <z ≦ 1
k: coefficient

( 12 ) In a blending design method for designing a raw material for sintering containing one or more of various iron ores at a predetermined blending ratio, each of the various iron ores is divided into coarse and fine grains,
(1) Indexing the porosity in the fired body of pseudo particles granulated by attaching limestone powder to various coarse iron ores as a nuclear characteristic index, and / or
(2) When the molded low-melting-point material is placed on various types of fine-grained iron ore and fired, the distance, cross-sectional area, and volume of the low-melting-point material melt penetrate into the fine-grained iron ore. Alternatively, melt permeability that is confirmed by measuring two or more is indexed as a powder characteristic index,
(3) Calculate the ratio of water of crystallization in the blended raw material from the blend ratio of ore,
(4) Sotsubutetsu ore was indexed the passing temper by attaching fine iron ore having a predetermined mass ratio to the core particles at a predetermined moisture granulated pseudo particles as breathable quality index,
(5) Based on the nuclear characteristic index and / or the powder characteristic index, and further, based on the ratio of water of crystallization in the blended raw material and the aeration characteristic index, a sintering productivity index SPI defined by the following formula (2) is calculated,
(6) Based on the sintering productivity index SPI, the sintering productivity of the sintering raw material is evaluated,
(7) A method for blending and designing a raw material for sintering, wherein the blending ratio of iron ore to be blended with the raw material for sintering is adjusted based on the evaluation result.

SPI = A ^x × B ^y × (1-D / 100) ± nC ^w (2)
A: Nuclear characteristic index B: Powder characteristic index D: Ratio of crystallization water in blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
n: contribution coefficient of ventilation characteristics, 0 <n ≦ 15
w: contribution rate of air permeability, 0 < w ≦ 1

( 13 ) The calculation of the sintering productivity index SPI of the above (5), the evaluation of the sintering productivity of the above (6), and the adjustment of the blending ratio of the above (7), The method for blending and designing a raw material for sintering according to the above ( 11 ) or ( 12 ), wherein the method is repeated until a predetermined value is reached.

( 14 ) Any one of the above ( 11 ) to ( 13 ), wherein the coarse iron ore is an iron ore having a particle size of 1 mm or more, and the fine iron ore is an iron ore having a particle size of less than 1 mm. A method for blending and designing raw materials for sintering as described in 1.

( 15 ) The characteristic of the coarse iron ore is a porosity in a fired body of pseudo particles granulated by attaching a mixed powder composed of limestone powder, fine iron ore and coke powder to the coarse iron ore. The method for evaluating a raw material for sintering according to any one of ( 11 ) to ( 14 ) above.

( 16 ) The characteristic of the fine-grained iron ore is a melt fluidity that is confirmed by measuring a bottom area after firing a mixed powder composed of fine iron ore and limestone powder formed into a cylindrical shape. The method for blending and designing raw materials for sintering according to any one of ( 11 ) to ( 15 ) above.

(17) passing temper the iron ore, mix design method of sintering raw material according to any one of the above, wherein said the average particle size of iron ore in the pseudo particles (11) - (16) .

( 18 ) The method for blending and designing a raw material for sintering according to any one of the above ( 11) to (17), wherein the nuclear property index A is defined by the following formula (1a).

A = Σ (a _i × p _i ) / Σ (p _i ) (1a)
a _i : Nuclear characteristic index of iron ore i
p _i : Mixing ratio of iron ore i having a particle diameter of 1 mm or more (%)

( 19 ) The method for blending and designing a raw material for sintering according to any one of the above ( 11) to (18), wherein the powder characteristic index B is defined by the following formula (1b).

B = Σ (b _i × q _i ) / Σ (q _i ) (1b)
b _i : Powder characteristic index of iron ore i
q _i : Mixing ratio (%) of iron ore i having a particle diameter of less than 1 mm

( 20 ) The blending design method for a raw material for sintering according to any one of ( 11) to (19), wherein the air permeability characteristic index C is defined by the following formula (1c): .

C = Σ (c _i × r _i ) / Σ (r _i ) (1c)
c _i : Aeration characteristic index of iron ore i
r _i : Mixing ratio of iron ore i (%)

( 21 ) The composition of the sintering raw material according to any one of the above ( 11) to (20), wherein a ratio of a particle size of 0.25 mm or less in the sintering raw material is 25% or less. Method.

  According to the present invention, it is possible to appropriately evaluate the sintering characteristics of a sintering raw material containing one or more types of iron ore at the raw material blending stage, so that a sintering raw material with better sintering characteristics is designed. can do.

  In addition, according to the present invention, even if cheap iron ore or iron ore that has not been used so far is used as a raw material for sintering, or frequent blending changes are made, the quality and product yield are good. Since stable sinter can be produced stably, blast furnace operation is stabilized, which contributes to improvement in productivity and reduction in fuel ratio.

  Hereinafter, the present invention will be described in detail. FIG. 1 shows the structure of pseudo particles obtained by granulating a raw material for sintering.

  The pseudo particles are usually composed of coarse iron ore (core particles) 1 having a particle size of 1 mm or more, fine iron ore (usually having a particle size of less than 1 mm) 2, limestone powder 3 and coke powder 4 In the sintering process, first, a low melting point calcium ferrite-based melt (hereinafter referred to as “melt”) is generated in the sintering process. Enters the adhering powder part, melts the constituent particles of the adhering powder, or bonds the particles together, and also enters the inside of the core particle to change the internal state of the core particle.

  FIG. 2 shows the structure of a sintered ore in which pseudo particles are bonded by a sintering reaction. As shown in FIG. 2, the sintered ore is basically composed of the original ore portion 5 mainly composed of core particles, and the core particle surface layer portion and the adhering powder portion where the melt has entered and the assimilation reaction has proceeded. It is composed of a substrate portion 6 including a fusion portion that fuses and encloses voids 7 and pores 10, and the properties of the substrate portion, and further the properties of the original ore portion, greatly affect the quality (strength, etc.) and product yield of the sintered ore. Affect.

  Therefore, if the properties of the above-mentioned substrate part, and further, the properties of the original ore part can be evaluated by some kind of index, it will be a guideline for selecting and blending iron ore, and the quality of the sintered ore and the product yield are required. The value can be controlled.

  In view of this, the present inventor has proposed “Evaluation Method of Iron Ore Powder” in Patent Document 1. This method evaluates the melt permeability to iron ore powder. This melt permeability is the degree of fusion between adhering powder parts that greatly affects the quality (strength, etc.) and yield of sintered ore. This is an index representing an aspect.

  Moreover, after sintering the tablet which shape | molded the mixed powder which consists of a fine iron ore and limestone powder currently disclosed by the nonpatent literature 2 at high temperature, the bottom area of a tablet is measured and melt fluidity | liquidity is measured. Even if the evaluation method is used for evaluation, similarly, the melt generation behavior of the adhered powder part can be accurately expressed, and the adhered powder parts greatly affecting the quality (strength, etc.) and yield of the sintered ore. It is an index that represents the degree and mode of fusion.

  Therefore, in the present invention, the brand characteristics of fine ore measured by any of the above methods are indexed as a powder characteristic index, and this index is an “index for evaluating and adjusting the sintering characteristics of the raw material for sintering. ".

  In addition, in the present invention, in addition to indexing the brand characteristics of fine ore, the characteristic values representing the properties of the surface layer portion of the core particle in which the melt has invaded and the assimilation reaction has progressed are indexed as the nuclear characteristic index. It is characterized by.

  Furthermore, in the present invention, in addition to the above two indexing, the air permeability of the sintered layer in the sintering process is remarkably inferior due to the ratio of water of crystallization in the blended raw material, and the structure and particle size distribution of the pseudo particles. Considering the phenomenon that the strength and yield of sintered ore decrease due to non-uniform firing, the aeration characteristics of pseudo particles granulated with coarse iron ore as core particles and fine iron ore attached thereto It is characterized by being indexed as an index.

  In the present invention, based on the nuclear characteristic index and / or the powder characteristic index, and further, based on the proportion of crystal water in the blended raw material and the aeration characteristic index, for sintering containing one or more kinds of iron ores In addition to evaluating the sintering characteristics of the raw materials, based on the evaluation results, select the type of iron ore to be blended with the raw materials for sintering, and further adjust the blending amount or blending ratio to obtain excellent sintering characteristics. It is characterized by designing a raw material for sintering.

  1) First, the indexing will be described.

(A) Nuclear characteristic index Conventionally, granulated by using coarse iron ore with a particle size of 1 mm or more as core particles and adhering only limestone powder or mixed powder consisting of limestone powder, fine iron ore and powdered coke around it. A fire (anabolic) test is conducted on the pseudo-particles, and the iron ore sintering characteristics are evaluated by the assimilation rate and assimilation (affecting air permeability and productivity) during the assimilation reaction with the melting of the coarse iron ore. Was.

  However, even though the above assimilation rate and assimilation properties can evaluate the sintering characteristics of coarse iron ore, which is the core particle, the relationship between the assimilation rate and the strength and yield of the sintered ore is not clear, and The assimilation properties of the sinter and the structure after assimilation of the sinter differ, and the results of the conventional assimilation tests show that the quality of the sinter ore and the sintering characteristics of the core particles that correlate closely with the yield The fact is that it has not been evaluated.

  Therefore, in the present invention, the “burned body porosity” in the fired body after assimilation of the coarse iron ore serving as the core particles is employed as an “index” representing the sintering characteristics of various coarse iron ores.

  This “calcined body porosity” (hereinafter referred to as “porosity”) indicates how much the melt formed around the core particles (coarse iron ore) spreads and permeates around the core particles. This is an “index” indicating whether the packed deposition layer is dense, that is, whether adjacent core particles can be firmly bonded and agglomerated.

  The evaluation of the sintering characteristics of coarse iron ore serving as core particles by “porosity” (index) will be further described.

  FIG. 1 shows the structure of pseudo particles, and FIG. 2 shows the structure of sintered ore in which pseudo particles are bonded by a sintering reaction. FIGS. 3 to 5 show the structure of sintered ore shown in FIG. The process leading to the structure of the ore is shown.

  FIG. 3 shows an enlarged view of the structure of the adhering powder portion of the pseudo particles shown in FIG. 1 (the portion marked with a circle in FIG. 1). Fine-grained iron ore 2 and limestone powder 3 are attached around the coarse iron ore 1 having voids 8 leaving the voids 7 (note that coke powder is not displayed).

When the coke powder burns in the adhering powder part shown in FIG. 3 and the pseudo particles are heated to around 1200 ° C., as shown in FIG. 4, the assimilation reaction between the limestone powder 3 and the fine-grained iron ore 2 reduces The melting point melt 9 (CaO.Fe ₂ O ₃ : calcium ferrite) starts to be generated.

  The melt 9 permeates into the gap 7 in the adhered powder portion at the same time as the generation. However, as shown in FIG. 5, the important thing is that the melt 9 quickly enters the gap 7 in the adhered powder portion. And also penetrates into the voids 8 existing in the surface layer portion of the coarse iron ore (nuclear particles) 5 to form a dense deposited layer (bonded phase) of fine nuclear particles with few pores 10 and voids 8. That is.

  Therefore, in the present invention, the pores remaining in the bonded phase after the assimilation reaction and the voids remaining in the original ore portion are regarded as “pores”, and the “porosity” of the existence ratio is expressed as an “index” indicating the sintering characteristics of iron ore. ".

  The density of the packed sedimentary layer correlates closely with the quality (strength) and yield of the sintered ore, and the smaller the porosity, the greater the density of the packed sedimentary layer. ) Is indexed based on (1-porosity).

  FIG. 6 schematically shows the technical meaning of the nuclear characteristic index (A). The nuclear characteristic index (A) indicates that when the raw material for sintering having the pseudo particle structure (a) is sintered, the sintered structure of the sintered ore composed of the original ore portion 5 and the substrate portion 6 is a dense structure (b). Or a sparse structure (c), which is a reference for judging from the characteristics of the coarse iron ore 1.

  Table 1 shows an example in which the porosity measured for various iron ores and the characteristics of various coarse iron ores are indexed as nuclear characteristic indices based on the porosity.

The porosity of the measurement method 1 shown in Table 1 is such that the limestone (CaCO ₃ ) powder having a particle size of −0.125 mm is around CaO / iron ore = 0.1 around various coarse iron ores of 3 to 5 mm. In this way, about 10 g is deposited, and this is filled into a Ni crucible having a diameter of 21 mm and a height of 15 mm (the porosity at the time of filling is constant for various coarse iron ores). In a fired body heated to 5 ° C. for 5 minutes, fired, cooled to 1275 to 1100 ° C. in 4 minutes, and then air-cooled from 1100 ° C., a gap of 50 μm or more in the cross section of the sintered body 5 mm from the bottom (fired) (Including pores generated in step 1)).

The porosity of measurement method 2 is that mixed powder consisting of limestone (CaCO ₃ ) powder with a particle size of −0.125 mm, fine iron ore powder, and coke powder is attached as an adhering powder around various coarse iron ores of 3 to 5 mm. It is the result of having baked on the conditions similar to the above, and measuring the porosity. The blending ratio of the mixed powder was adjusted so as to be close to the composition of the adhered powder layer in the pseudo particles of the actual machine.

  The porosity of the measurement method 1 and the measurement method 2 shown in Table 1 is slightly different from the measurement conditions, but it can be seen that the difference due to the difference is slight when evaluated as a nuclear characteristic index. That is, even if any one of the measuring methods 1 and 2 is used, the evaluation based on the characteristics of the ore brand as a nuclear ore is possible.

  Moreover, the measuring method of a porosity is not limited to said measuring method. In the present invention, since it is important to index the measured value as a nuclear characteristic index, it is only necessary to obtain measured values measured under certain conditions for various brands of iron ore.

  Table 1 shows the nuclear characteristic index obtained by indexing (1-porosity) based on the measured porosity, but instead of the porosity, the residual mineral ratio was measured and used as the nuclear characteristic index. It may be indexed.

  The residual raw mineral ratio is represented by (R / s) × 100 (R: residual raw ore area [residual original ore: portion where the melt does not penetrate macroscopically], s: calcined body area), (1 -An index corresponding to (porosity).

  Further, instead of the porosity, the fired body drop strength may be measured and indexed as a nuclear characteristic index. Since the fired body drop strength is an index that directly depends on the density of the packed deposited layer, it is preferable as an index that represents the core particle characteristics.

  In the present invention, it is a matter of course that an index other than the above may be used as long as it is an index that can be indexed as a nuclear characteristic index.

(B) Powder characteristic index As described above, the present inventor proposed a method for evaluating fine iron ore having a particle diameter of less than 1 mm in Patent Document 1. In this method, a molded low melting point material is placed on a molded body having a predetermined porosity formed from fine iron ore of less than 1 mm, and the melting point is raised to 1000 ° C. or higher in the atmosphere or in a low oxygen atmosphere. A substance is melted, the melt is allowed to penetrate into the molded body, and one or more of the distance, cross-sectional area and volume permeated by the melt are measured, and the measured value (melt penetration distance) , Cross-sectional area, volume) and evaluating the melt permeability of various iron ores.

  This melt permeation distance (or cross-sectional area, volume) is determined by the flow of the low-melting calcium ferrite-based melt generated at the initial stage and the melt generated by assimilation of the ore fine powder part in the adhering powder part of the pseudo particles during firing. This indicates the degree of fluid flow, so that the difference in melt permeability between fine particles of iron ore of various brands is clarified, and the adhered powder part that greatly affects the quality (strength, etc.) and yield of sintered ore It becomes an index indicating the degree and mode of fusion between each other.

  The longer the melt penetration distance, the wider the initial melt produced can be at the adhering powder part, and the higher the bond strength, the higher the quality (strength) and yield of the sintered ore. The liquid penetration distance is indexed as a powder characteristic index.

  Non-Patent Document 2 describes a method for evaluating melt fluidity by measuring the bottom area of a tablet after sintering a tablet of mixed powder composed of fine iron ore and limestone powder formed into a cylindrical shape at high temperature. Is disclosed.

  The inventors of the present invention also have a low melting point initial melt produced by the reaction between fine ore and limestone powder in the initial stage of sintering, and melt the surrounding ore. The behavior is evaluated by the degree of deformation of the tablet, and it is confirmed that the index has a good correlation with the melt penetration distance in the evaluation method of Patent Document 1.

  That is, the measured value of the bottom area after the tablet baking can be used in addition to the melt permeation distance as a powder characteristic index representing the characteristics of fine ore used for blending design.

  FIG. 6 schematically shows the technical meaning of the powder characteristic index (B). The powder characteristic index (B) indicates that when the raw material for sintering having the pseudo particle structure (a) is sintered, the sintered structure of the sintered ore composed of the original ore portion 5 and the substrate portion 6 is a dense structure (b). Or a sparse structure (c), which is a reference for judging from the characteristics of the fine-grained iron ore 2.

  Table 2 shows an example in which the melt penetration distance or the bottom area after tablet firing is measured for various iron ores, and the characteristics of various fine-grained iron ores are indexed as powder characteristic indices based on the measured values. Show.

  In the present invention, instead of the melt infiltration distance shown in Table 1, it can be indexed by using the measured value of the melt infiltration cross-sectional area or the melt infiltration volume. The liquid permeability can be evaluated more appropriately.

(C) Aeration characteristic index The yield and strength of sintered ore can be evaluated by the melt generation behavior of various iron ores using the above-mentioned nuclear characteristic index and powder characteristic index. However, in order to properly evaluate the sintering productivity of various iron ores, the evaluation index is the aeration characteristics of pseudo particles that greatly affect the aeration characteristics of the sintered layer during the sintering process as well as the yield of the sintered ore. Need to add.

  The air permeability of the sintered layer in the sintering process is greatly influenced by the structure of the pseudo particles of the blended raw material and the particle size distribution constituting the pseudo particles. The structure of the pseudo particles of various iron ores is thought to depend on the characteristics of the coarse iron ore (nuclear particles) constituting the pseudo particles and the characteristics of the fine iron ore that forms the adhering part. It is difficult to index the structure of

  Therefore, in the present invention, the permeability of the pseudo particles granulated by attaching the coarse iron ore as the core particle and attaching the fine iron ore of a predetermined mass ratio with the predetermined moisture, and measuring the permeability By indexing, the sintering productivity of various iron ores is accurately evaluated.

  For example, JPU defined by the following formula (3) may be used as the breathability of the pseudo particles. However, in the present invention, any other index can be used as long as it is an index that can be indexed as a breathability index. Of course it is good.

JPU = Ventilation volume (Nm ³ / min) / Ventilation area (m ² )
× [Layer thickness (mm) / Suction pressure (mmH ₂ O)] ^0.6 (3)
In the present invention, it is also possible to evaluate the sintering productivity of various iron ores using the average particle size depending on the particle size distribution of the iron ore constituting the pseudo particles of various iron ores as the air permeability index. .

  Table 3 shows an example of the breathability measurement value JPU of the pseudo particles or the breathability index indexed using the average particle size.

  2) Next, using the nuclear characteristic index and / or the powder characteristic index and the air permeability index, the sintering productivity index of various iron ores is calculated, and the sintering raw material is sintered based on the index. The evaluation of the productivity is explained.

  The strength and yield of the sintered ore can be evaluated by the nuclear characteristic index and / or the powder characteristic index of the iron ore in the evaluation method proposed by the present inventors in Patent Document 5.

  In this case, there is no big mistake in evaluating the sintering characteristics of either the nuclear characteristic index or the powder characteristic index, but the raw material for sintering includes coarse iron ore and fine iron ore. Therefore, it is expected that the sintering characteristics are a combination of the sintering characteristics of the coarse-grained iron ore and the sintering characteristics of the fine-grained iron ore (see FIG. 6).

  However, in order to properly evaluate the productivity of iron ore, the evaluation method proposed in Patent Document 5 is not sufficient, and in addition to the nuclear characteristic index and the powder characteristic index, the evaluation is further based on the air permeability index. There is a need to.

  Therefore, in this invention, in order to evaluate appropriately the sintering productivity of the raw material for sintering comprehensively, it evaluates according to following formula (1) or (2).

^{SPI = k × A x × B} y × (1-D / 100) × C z ... (1)
SPI = A ^x × B ^y × (1-D / 100) ± nC ^w (2)
A: Nuclear characteristic index,
B: Powder characteristic index D: Crystal water ratio of blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
z, w: contribution rate of air permeability, 0 <z ≦ 1, 0 <w ≦ 1
n: contribution coefficient of air permeability, 0 <n ≦ 15
k: coefficient

  Since the aeration characteristic of the raw material for sintering can also be considered as an ore combination effect, in the present invention, the aeration characteristic index contributes synergistically to the nuclear characteristic index and the powder characteristic index. Assuming the case, the above two formulas were defined.

  In the above formula (2), D is the ratio of crystallization water in the iron ore of the blending raw material. When there is a lot of crystallization water in the blending raw material, the crystallization water in the iron ore is dehydrated during the sintering process. For this reason, since productivity decreases with a decrease in firing yield, it is considered as an influential factor in the evaluation of sintering productivity.

  In the present invention, the relational expression for indicating the sintering productivity index SPI by the nuclear characteristic index A and / or the powder characteristic index B and the air permeability index C is expressed by the above formulas (1) and (2). It is not limited. As long as the sinter productivity index SPI shows a very good correlation with the sinter productivity, any functional formula may be used.

For example, p · A ^x × q · B ^y / r · C ^z , (p · A ± r ₁ · C) ^x · (q · B ± r ₂ · C) ^y may be used, and p · A ^x + Q · B ^y + r · C ^z (p, q, r: coefficient, 0 <x, y, z).

  When the sintering raw material contains two or more types of iron ore (powder), the nuclear characteristic index A, the powder characteristic index B, and the air permeability index C in the above two formulas are respectively the following formulas (1a) Formula (1b) and Formula (1c).

A = Σ (a _i × p _i ) / Σ (p _i ) (1a)
a _i : Nuclear characteristic index of iron ore i
p _i : Mixing ratio of iron ore i having a particle diameter of 1 mm or more (%)
B = Σ (b _i × q _i ) / Σ (q _i ) (1b)
b _i : Powder characteristic index of iron ore i
q _i : Mixing ratio (%) of iron ore i having a particle diameter of less than 1 mm
C = Σ (c _i × r _i ) / Σ (r _i ) (1c)
c _i : Aeration characteristic index of iron ore i
r _i : Mixing ratio of iron ore i (%)

  According to the inventor's research survey, x and y in the above formulas (1) and (2) are each preferably 0.1 or more and 0.5 or less and 0.5 or more and 1 or less, respectively, , 0.3 and 1 are more preferred.

  Z is preferably 0.2 or more and 1.5 or less, and more preferably 0.5 or 1.

N is preferably 0.5 or more and 11 or less, and more preferably 1, 1.5, 2 or 10.
w is preferably 0.2 or more and 0.7 or less, and more preferably 0.5.

  The coefficient k adjusts the magnitude of the calculated value of the SPI, and an arbitrary value may be given depending on convenience.

  Here, with respect to the sintering raw material containing two or more kinds of iron ores, the core characteristic index and the powder characteristic index of various iron ores shown in Table 1 and Table 2, respectively, and the air permeability characteristic index shown in Table 3 are used. Sintering productivity index SPI according to the above formula (1) with x = 0.3, y = 1, z = 1, k = 0.0125 under the blending amounts shown in FIG. Table 4 shows the calculated results.

  FIG. 7 shows the relationship between the production rate of sintered ore obtained by sintering the sintering raw material having the sintering productivity index SPI shown in Table 4 (50 kg pan test) and the sintering productivity index SPI. Show.

  From these figures, it can be seen that the production rate of sintered ore and the sintered productivity index determined from the above equation (1) are in a very good correlation.

  Further, in the above formula (2), the relationship between the sintered productivity index SPI with x = 0.3, y = 1, w = 1, n = 1 and the production rate of sintered ore is shown in FIG. .

  From these figures, it can be seen that the production rate of sintered ore and the sintered productivity index obtained by the above equation (2) are in a very good correlation.

  3) Next, a method for blending and designing the raw materials for sintering based on the sintering productivity index SPI of various iron ores will be described.

  As described above, the sintering productivity index SPI defined by each formula of the present invention shows a very good correlation with the production rate of the sintered ore, and therefore, for sintering containing one or more kinds of iron ores. Based on the raw material sintering productivity index SPI, the production rate of sintered ore obtained by sintering the raw material for sintering can be accurately estimated.

  Since iron ore is similar in composition, it has completely different properties and forms of ore due to the difference in the ore deposit (production area). Therefore, strength and product yield from sintering raw materials containing two or more of these iron ores are mixed. When trying to produce a sintered ore with an excellent production rate, conventionally, the amount or ratio of iron ore has to be determined by trial and error.

  However, according to the present invention, the production rate of sintered ore can be accurately estimated by knowing in advance the productivity index of the raw material for sintering. That is, by evaluating the sintering productivity of the raw material for sintering according to the present invention, it is possible to determine the suitability of the characteristics of the raw material for sintering, and based on this evaluation result, the iron ore blended in the raw material for sintering Stone type, blending amount and blending ratio can be selected and adjusted.

  In the present invention, the nuclear characteristic index, the powder characteristic index, and the aeration characteristic index were used to calculate the sintering characteristic index. Furthermore, the raw material productivity that affects the sintering, for example, granulation property In addition, the iron ore adhesion force, the optimum water content, etc. may be indexed and added to the calculation of the sintering productivity index.

Example 1
As in the blending examples shown in Table 5, the raw materials for sintering are blended at a predetermined ratio, and the ratio of other auxiliary raw materials such as limestone, serpentine, and quartzite is adjusted, and the sintered ore SiO ₂ , CaO / SiO _2. The ratio of MgO was not changed greatly. The blended raw material thus adjusted was sintered in a sintering pot test, and cold strength, product yield, and production rate were measured.

  Using the nuclear characteristic index, powder characteristic index, and aeration characteristic index shown in Table 1, Table 2, and Table 3, respectively, Equation (1) (x = 0.3, y = 1, Z = 1, k = Table 5 shows the sintered productivity index SPI calculated in 0.0125) and the actually measured production rate. Table 5 also shows the cold strength and product yield of the sintered ore actually measured for reference.

  As a result, in comparison with Formulation 1, Formulation 2 had a higher sintered productivity index SPI, and could be evaluated as an ore formulation that can achieve high productivity of sintered ore. From the fact that the measured productivity of sintered ore is superior to that of Formula 2, it can be understood that the productivity of sintered ore can be appropriately evaluated by the evaluation method of the present invention.

  Moreover, it turns out that the cold strength and product yield of the sintered ore actually measured for reference can also be appropriately evaluated by the evaluation method of the present invention.

(Example 2)
Next, in an actual machine sintering machine having a sintering area of 480 m ² and a sintering pallet width of 4 m, an operation for applying the method of the present invention was performed. In the method of the present invention, the sintering productivity index SPI calculated by the formula (1) (X = 0.3, y = 1, z = 1, k = 0.0125) under the base condition was 155. When the production rate of sintered ore was in a downward trend, the composition of the raw materials for sintering was adjusted so as to improve the sintering productivity index SPI.

  While changing the composition of the sintering raw material at a frequency of 2 to 3 times a week, we investigated the cold strength, product yield, and fluctuations in the production rate of the sintered ore before and after applying the method of the present invention. It was.

  Fig. 9 shows the changes in the production rate, product yield and cold strength of the sintered ore before and after the application of the method of the present invention in the operation of the actual sintering machine for two months, and the transition of the sintered production index SPI. Show. After applying the method of the present invention, the sintering productivity index SPI was maintained at a constant value of 155 even when the mixing of the sintering raw material was frequently changed, so that the sintering ore quality and product yield were ensured while sintering was performed. The production rate of the ore was stabilized at a high level. As the production rate of the sinter was stabilized and the variation in the quality of the sinter was reduced, blast furnace operation was extremely stable.

It is a figure which shows typically the structure of the pseudo particle which granulated the raw material for sintering. It is a figure which shows typically the structure of the sintered ore which the pseudo particle couple | bonded by sintering reaction. It is a figure which expands and shows a part of structure of the pseudo particle shown in FIG. It is a figure which shows the aspect of the melt produced | generated in the adhering powder part at the initial stage of sintering reaction. It is a figure which shows the aspect which the assimilation reaction advanced and the melt was osmose | permeating the space | gap in the space | gap in an adhesion powder part, and a coarse-grained ore (nuclear particle) surface part. It is a figure which shows the technical meaning of a nuclear characteristic index and a powder characteristic index. (A) is a figure which shows the structure of a pseudo particle. (B) is a figure which shows a precise | minute sintered structure, (c) is a figure which shows an empty sintered structure. It is a figure which shows the relationship between the sintering productivity index | exponent SPI of Formula (1), and the production rate of a sintered ore. It is a figure which shows the relationship between the sintering productivity index | exponent SPI of Formula (2), and the production rate of a sintered ore. It is a figure which shows transition of the product yield and cold strength before and after application of the method of the present invention in the operation of an actual sintering machine for two months.

Explanation of symbols

1 Coarse iron ore (+ 1mm or more)
2 Fine iron ore (less than -1mm)
3 Limestone powder 4 Coke powder 5 Original mineral part 6 Substrate part 7, 8 Void 9 Melt 10 Pore A Nuclear characteristic index B Powder characteristic index

Claims (21)

In the evaluation method for evaluating the characteristics of the raw material for sintering containing one or more of various iron ores at a predetermined blending ratio, each of the various iron ores is divided into coarse particles and fine particles,
(1) Indexing the porosity in the fired body of pseudo particles granulated by attaching limestone powder to various coarse iron ores as a nuclear characteristic index, and / or
(2) When the molded low-melting-point material is placed on various types of fine-grained iron ore and fired, the distance, cross-sectional area, and volume of the low-melting-point material melt penetrate into the fine-grained iron ore. Alternatively, melt permeability that is confirmed by measuring two or more is indexed as a powder characteristic index,
(3) Calculate the ratio of water of crystallization in the blended raw material from the blend ratio of ore,
(4) Sotsubutetsu ore was indexed the passing temper by attaching fine iron ore having a predetermined mass ratio to the core particles at a predetermined moisture granulated pseudo particles as breathable quality index,
(5) Sintering characterized in that the sintering productivity of the raw material for sintering is evaluated based on the nuclear characteristic index and / or the powder characteristic index, and further the ratio of water of crystallization in the blended raw material and the aeration characteristic index For evaluating raw materials.   The method for evaluating a raw material for sintering according to claim 1, wherein the coarse iron ore is an iron ore having a particle size of 1 mm or more, and the fine iron ore is an iron ore having a particle size of less than 1 mm.   The characteristic of the coarse iron ore is a porosity in a sintered body of pseudo particles granulated by attaching a mixed powder composed of limestone powder, fine iron ore and coke powder to the coarse iron ore. Item 3. The method for evaluating a raw material for sintering according to Item 1 or 2. The characteristic of the fine-grained iron ore is a melt fluidity that is confirmed by measuring a bottom area after firing a mixed powder composed of fine iron ore and limestone powder formed into a cylindrical shape. The evaluation method of the raw material for sintering of any one of 1-3 . Passing temper of the iron ore, the evaluation method of the sintering raw material according to claim 1-4 any one of, wherein said the average particle size of iron ore in the pseudo particles. Based on the nuclear characteristic index and / or the powder characteristic index, and further the crystallization water ratio and the aeration characteristic index, a sintering productivity index SPI defined by the following formula (1) is calculated, and the sintering productivity index SPI is calculated. based on the evaluation method of the sintering raw material according to any one of claims 1 to 5, characterized in that to evaluate the sintering productivity of the for sintering the raw material.
^{SPI = k × A x × B} y × (1-D / 100) × C z ... (1)
A: Nuclear characteristic index B: Powder characteristic index D: Ratio of crystallization water in blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
z: contribution rate of air permeability, 0 <z ≦ 1
k: coefficient A sintering productivity index SPI defined by the following formula (2) is calculated based on the nuclear characteristic index and / or the powder characteristic index, and further, the ratio of water of crystallization and the aeration characteristic index, and based on the sintering characteristic index SPI. The method for evaluating a sintering raw material according to any one of claims 1 to 5 , wherein the sintering productivity of the sintering raw material is evaluated.
SPI = A ^x × B ^y × (1-D / 100) ± nC ^w (2)
A: Nuclear characteristic index B: Powder characteristic index D: Ratio of crystallization water in blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
n: contribution coefficient of ventilation characteristics, 0 <n ≦ 15
w: contribution rate of air permeability, 0 < w ≦ 1 The method for evaluating a raw material for sintering according to claim 6 or 7 , wherein the nuclear characteristic index A is defined by the following formula (1a).
A = Σ (a _i × p _i ) / Σ (p _i ) (1a)
a _i : Nuclear characteristic index of iron ore i
p _i : Mixing ratio of iron ore i having a particle diameter of 1 mm or more (%) The method for evaluating a raw material for sintering according to any one of claims 6 to 8, wherein the powder characteristic index B is defined by the following formula (1b).
B = Σ (b _i × q _i ) / Σ (q _i ) (1b)
b _i : Powder characteristic index of iron ore i
q _i : Mixing ratio (%) of iron ore i having a particle diameter of less than 1 mm The method for evaluating a raw material for sintering according to any one of claims 6 to 9, wherein the gas permeability characteristic index C is defined by the following formula (1c).
C = Σ (c _i × r _i ) / Σ (r _i ) (1c)
c _i : Aeration characteristic index of iron ore i
r _i : Mixing ratio of iron ore i (%) In a blending design method for designing a raw material for sintering containing one or more of various iron ores at a predetermined blending ratio, each of the various iron ores is divided into coarse grains and fine grains,
(1) Indexing the porosity in the fired body of pseudo particles granulated by attaching limestone powder to various coarse iron ores as a nuclear characteristic index, and / or
(2) When the molded low-melting-point material is placed on various types of fine-grained iron ore and fired, the distance, cross-sectional area, and volume of the low-melting-point material melt penetrate into the fine-grained iron ore. Alternatively, melt permeability that is confirmed by measuring two or more is indexed as a powder characteristic index,
(3) Calculate the ratio of water of crystallization in the blended raw material from the blend ratio of ore,
(4) Sotsubutetsu ore was indexed the passing temper by attaching fine iron ore having a predetermined mass ratio to the core particles at a predetermined moisture granulated pseudo particles as breathable quality index,
(5) Calculate the sintering productivity index SPI defined by the following formula (1) based on the nuclear characteristic index and / or the powder characteristic index, and further, the ratio of water of crystallization in the blended raw material and the aeration characteristic index,
(6) Based on the sintering productivity index SPI, the sintering productivity of the sintering raw material is evaluated,
(7) A method for blending and designing a raw material for sintering, wherein the blending ratio of iron ore to be blended with the raw material for sintering is adjusted based on the evaluation result.
^{SPI = k × A x × B} y × (1-D / 100) × C z ... (1)
A: the number of nuclear properties finger
B: Powder characteristic index D: Crystal water ratio of blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
z: contribution rate of air permeability, 0 <z ≦ 1
k: coefficient In a blending design method for designing a raw material for sintering containing one or more of various iron ores at a predetermined blending ratio, each of the various iron ores is divided into coarse grains and fine grains,
(1) Indexing the porosity in the fired body of pseudo particles granulated by attaching limestone powder to various coarse iron ores as a nuclear characteristic index, and / or
(2) When the molded low-melting-point material is placed on various types of fine-grained iron ore and fired, the distance, cross-sectional area, and volume of the low-melting-point material melt penetrate into the fine-grained iron ore. Alternatively, melt permeability that is confirmed by measuring two or more is indexed as a powder characteristic index,
(3) Calculate the ratio of water of crystallization in the blended raw material from the blend ratio of ore,
(4) Sotsubutetsu ore was indexed the passing temper by attaching fine iron ore having a predetermined mass ratio to the core particles at a predetermined moisture granulated pseudo particles as breathable quality index,
(5) Based on the nuclear characteristic index and / or the powder characteristic index, and further, based on the ratio of water of crystallization in the blended raw material and the aeration characteristic index, a sintering productivity index SPI defined by the following formula (2) is calculated,
(6) Based on the sintering productivity index SPI, the sintering productivity of the sintering raw material is evaluated,
(7) A method for blending and designing a raw material for sintering, wherein the blending ratio of iron ore to be blended with the raw material for sintering is adjusted based on the evaluation result.
SPI = A ^x × B ^y × (1-D / 100) ± nC ^w (2)
A: Nuclear characteristic index B: Powder characteristic index D: Ratio of crystallization water in blended raw material (%)
C: aeration characteristic index x: contribution ratio of nuclear characteristics, 0 ≦ x ≦ 1 (provided that x ≠ 0 when y = 0)
y: contribution ratio of powder characteristics, 0 ≦ y ≦ 1 (y ≠ 0 when x = 0)
n: contribution coefficient of ventilation characteristics, 0 <n ≦ 15
w: contribution rate of air permeability, 0 < w ≦ 1 The calculation of the sintering productivity index SPI of the above (5), the evaluation of the sintering productivity of the above (6), and the adjustment of the blending ratio of the above (7), the sintering productivity index reaches a predetermined value. The method for blending and designing a raw material for sintering according to claim 11 or 12 , wherein the method is repeatedly performed. Wherein a coarse iron ore particle diameter 1mm or more iron ore, baked according to any one of claims 11 to 13, wherein the fine particle iron ore, characterized in that an iron ore of particle size less than 1mm Formulation design method of ligation raw materials. The characteristic of the coarse iron ore is a porosity in a sintered body of pseudo particles granulated by attaching a mixed powder composed of limestone powder, fine iron ore and coke powder to the coarse iron ore. Item 15. The method for evaluating a raw material for sintering according to any one of Items 11 to 14 . The characteristic of the fine-grained iron ore is a melt fluidity that is confirmed by measuring a bottom area after firing a mixed powder composed of fine iron ore and limestone powder formed into a cylindrical shape. The method for blending and designing raw materials for sintering according to any one of 11 to 15 . Passing temper of the iron ore, the mix design method of sintering raw material according to any one of claims 11 to 16, characterized in that the average particle size of iron ore in the pseudo particles. The said nuclear characteristic index | exponent A is defined by following formula (1a), The mixing | blending design method of the raw material for sintering of any one of Claims 11-17 characterized by the above-mentioned.
A = Σ (a _i × p _i ) / Σ (p _i ) (1a)
a _i : Nuclear characteristic index of iron ore i
p _i : Mixing ratio of iron ore i having a particle diameter of 1 mm or more (%) The method for blending and designing a raw material for sintering according to any one of claims 11 to 18, wherein the powder characteristic index B is defined by the following formula (1b).
B = Σ (b _i × q _i ) / Σ (q _i ) (1b)
b _i : Powder characteristic index of iron ore i
q _i : Mixing ratio (%) of iron ore i having a particle diameter of less than 1 mm The method for blending and designing a raw material for sintering according to any one of claims 11 to 19, wherein the air permeability characteristic index C is defined by the following formula (1c).
C = Σ (c _i × r _i ) / Σ (r _i ) (1c)
c _i : Aeration characteristic index of iron ore i
r _i : Mixing ratio of iron ore i (%) 21. The method for blending and designing a raw material for sintering according to any one of claims 11 to 20, wherein a ratio of a particle size of 0.25 mm or less in the raw material for sintering is 25% or less.

Images