JP6264517B1 - Method for producing carbonaceous interior sinter - Google Patents

Abstract

Provided is a method for producing a carbonaceous material-containing sintered ore that can produce a carbonaceous material-containing sintered ore that can improve the reduction efficiency with high productivity. Downward suction-type sintering of a sintering raw material formed by blending carbonaceous material interior particles in which an outer layer made of a raw material containing iron ore powder and CaO is formed around the carbonaceous material core into normal granulated particles A method for producing a carbonaceous material-containing sintered ore that is charged into a pallet of a machine to produce a sintered ore, wherein the blending ratio of the carbonaceous material-containing particles with respect to the sintering raw material is in the range of 10% by mass to 30% by mass. Is within.

Description

  The present invention relates to a technique for producing sintered ore used as a steelmaking raw material in a blast furnace or the like, and specifically, granulated particles containing carbonaceous materials (hereinafter referred to as carbonaceous material interior particles) as sintered raw materials. It is related with the manufacturing method of the carbonaceous material interior sintered ore made into a part of.

In the blast furnace iron manufacturing method, iron-containing raw materials such as iron ore and sintered ore are mainly used as iron sources. The sintered ore is manufactured by the following procedure. Iron ore with a particle size of 10mm or less, SiO ₂ containing raw materials made of silica, serpentine, refined nickel slag, etc., auxiliary materials made of CaO containing raw materials such as limestone and quicklime, and coagulant made of powdered coke or anthracite Then, an appropriate amount of water is added to the sintering raw material composed of and mixed and granulated using a drum mixer or the like to obtain pseudo particles. The sintering raw material made into the pseudo particles is charged into a pallet that circulates and moves in the sintering machine. In the sintering machine, the carbonaceous material contained in the sintered raw material is burned and sintered, and the sintered raw material made into pseudo particles becomes a sintered cake. The sintered cake is crushed, cooled, and sized, and a product having a certain particle size or more is recovered as a product sintered ore. Sintered ore is a kind of agglomerated ore thus produced.

  In recent years, a carbonaceous material agglomerated ore in which an iron source such as iron ore and dust and a carbonaceous material such as coke are placed in close proximity has attracted attention as the agglomerated mineral. The reason is that by placing the iron source such as iron ore and the carbonaceous material close together in one agglomerated ore, the reduction efficiency can be improved and the temperature of the upper part of the blast furnace can be lowered. Because.

  As such agglomerated minerals, Patent Document 1 discloses, as raw materials in which iron-containing powders generated in the iron making process such as blast furnace / converter dust, rolling scale, sludge, iron ore powder, etc. are used alone or in combination, coal, coke, etc. The pellets for iron-making raw materials are disclosed, which are granulated by adding a carbonaceous material and starch, mixing and kneading, and further supplying a starch solution with a granulator. However, since the pellets for iron-making raw materials disclosed in Patent Document 1 burn out the carbonaceous material in the pellets during the production of sintered ore, the iron-containing raw material such as iron ore and the carbonaceous material are actually arranged close to each other. It is not a thing. Also, simply reducing the particle size of iron ore or carbon for the purpose of close placement increases the resistance of gas to propagate heat too much, leading to a decrease in reaction rate and a reduction in reduction efficiency. I will let you.

  Techniques aimed at the close arrangement of the iron ore and the carbon material are also disclosed in Patent Documents 2 to 5. The technology disclosed in these is a mixture of iron-containing raw materials such as iron ore and carbonaceous materials such as coke, and then agglomerated by hot forming, or in a blast furnace or the like as raw particles without firing. Used as a raw material for iron making. However, these agglomerates are non-fired ones composed of a uniform mixture or multi-layered granulated material, so that the strength is insufficient and pulverization becomes intense. For this reason, when this is inserted into a blast furnace or the like, dehydration or reduction powdering is caused and the air permeability of the blast furnace is hindered, so that the amount used is limited.

  As a technique for solving such a problem, a technique of carbon material interior agglomeration has been proposed. In Patent Document 6, a low-oxidation iron oxide shell is formed by coating iron oxide powder containing metal iron such as iron dust and mill scale around a carbon material core made of small coke using a granulator. After the coating is formed, a hard thin layer made of iron oxide having a high degree of oxidation only on the surface of the iron oxide shell by heating in the atmosphere at a temperature of 200 ° C. or higher and lower than 300 ° C. for 0.5 to 5 hours for oxidation treatment. A technique for obtaining an agglomerated carbonaceous material agglomerated mineral by forming a steel is disclosed.

  In Patent Document 7, iron oxide powder such as iron-making dust or mill scale or iron ore powder and carbonaceous material are mixed and granulated using a granulator, and then metal iron-containing oxide is formed on the outer surface of the granulated product. The technology to obtain agglomerates containing coke powder with a size of 3 mm or less in a dispersed state in iron oxide powder or iron ore powder by coating iron powder and forming a low oxidation iron oxide shell. It is disclosed. Further, Patent Document 8 discloses a method of producing carbonaceous material interior particles in which a carbonaceous material is coated with iron ore powder and a CaO-containing raw material, mixing this with a sintering raw material, and then sintering in a downward suction type sintering machine. Has been.

JP 2001-348625 A Japanese Patent No. 3502008 Japanese Patent No. 3502011 JP 2005-344181 A JP 2002-241853 A JP 2011-195943 A JP 2011-225926 A Japanese Patent No. 5790966

Sato, Satoshi, Yoshinaga, Mayumi Ichidate, Satoshi Kawaguchi, Shinzo Kawaguchi, Study of granulation of sintering raw materials and modeling of aeration phenomenon, Iron and Steel, 1982, Vol. 68, no. 15, 2174-2181

  According to the techniques disclosed in Patent Documents 6 and 7, the iron-containing raw material has a suitable size and sufficient strength, and since the iron-containing raw material and the carbonaceous material are arranged close to each other, a reduction reaction is easily caused and the temperature is low. A carbonaceous material-containing sintered ore that can be reduced can be obtained. However, in order to carry out these technologies, it is necessary to have equipment for heating treatment in the atmosphere at a temperature of 200 ° C. or more and less than 300 ° C. for 0.5 to 5 hours, and there is a limit to the production amount. There's a problem.

  The technique disclosed in Patent Document 8 solves the production limit by producing a carbonaceous material-containing sintered ore with a sintering machine, but what is the mixing ratio of carbonaceous material-containing particles into the sintering raw material? Not considered. If the blending ratio of carbonaceous material interior particles in the sintered raw material is too high, it will lead to a decrease in productivity due to a decrease in strength of the carbonaceous material interior sintered ore, and the blending ratio of carbonaceous material interior particles in the sintering raw material is too low. In this case, there is a possibility that the effect of improving the reduction efficiency cannot be enjoyed.

  This invention is made | formed in view of the said subject, The objective provides the manufacturing method of the carbonaceous material interior sintered ore which can manufacture the carbonaceous material interior sintered ore which can improve reduction efficiency with high productivity. There is.

  The features of the present invention for solving such problems are as follows.

  (1) Suction raw material is drawn downward by mixing carbonaceous material interior particles, in which an outer layer made of a raw material containing iron ore powder and CaO, is formed into normal granulated particles around the carbonaceous material core. It is a manufacturing method of a carbonaceous material-containing sintered ore that is charged into a pallet of a ceramic sintering machine to produce a sintered ore, and the blending ratio of the carbonaceous material-containing particles with respect to the sintering raw material is 10% by mass or more and 30%. The manufacturing method of a carbonaceous material interior sintered ore which is in the range of the mass% or less.

  (2) The method for producing a carbonaceous material-containing sintered ore according to (1), wherein a blending ratio of the carbonaceous material-containing particles with respect to the sintered raw material is in a range of 15% by mass to 25% by mass.

  By carrying out the method for producing a carbonaceous material-containing sintered ore of the present invention, it is possible to improve the air permeability of the charging layer formed by the sintered raw material containing the carbonaceous material-containing particles. Since the charging layer with improved air permeability can be sintered in a short time, the carbonaceous material-containing sintered ore that can improve the reduction efficiency is high by implementing the method for producing the carbonized material-containing sintered ore of the present invention. Can be manufactured with productivity.

Drawing 1 is a mimetic diagram explaining an example of the manufacturing method of the carbonaceous material interior sintered ore concerning this embodiment. FIG. 2 is a graph showing the relationship between the carbonaceous material interior particle blending ratio, the charging density, and the air permeability. FIG. 3 is a graph showing the relationship between the carbonaceous material interior particle content ratio, the cold strength, and the reducibility. FIG. 4 is a graph showing the relationship between the blending ratio of carbonaceous material interior particles having a carbonaceous material core interior ratio of 97 mass%, 90 mass%, and 80 mass% and the sintered ore production rate.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Drawing 1 is a mimetic diagram explaining an example of the manufacturing method of the carbonaceous material interior sintered ore concerning this embodiment. The manufacturing method of carbonaceous material interior particle | grains and a carbonaceous material interior sintered ore is demonstrated using FIG.

  As shown in FIG. 1, first, a raw material containing iron ore powder and quicklime (CaO) is uniformly mixed using a kneader to obtain a mixture. The mixture and coke particles having a particle diameter of 3 mm or more serving as a carbon material core are supplied to a granulator, and a predetermined amount of water is added. In the granulator, an outer layer made of a mixed powder in which iron ore powder and quicklime are homogenized is formed around the coke particles by the bridging power of water, and the carbonaceous material-containing particles having a particle size of 5 mm or more are granulated. Is done. In such a granulation process, the carbonaceous material interior particles are granulated, but not all of the granulated carbonaceous material interior particles are equipped with the carbonaceous material core, but some of the carbonaceous material cores are interiorized. Not containing granulated particles. In the present embodiment, the carbonaceous material-incorporated particles are granulated particles that are granulated in the granulation step, and include granulated particles that have carbonaceous material cores and granulated particles that do not have some carbonaceous material cores. means. In addition, the particle size in this embodiment is a particle size screened using a sieve with a nominal opening based on JIS (Japanese Industrial Standards) Z8801-1. For example, a particle size of 3 mm or more is It refers to the particle size that is sieved on the sieve using a sieve with a nominal aperture of 3 mm in accordance with JIS Z8801-1.

Next, carbonaceous material interior particles are blended with pseudo particles which are normal granulated particles stirred and granulated with a drum mixer or the like to obtain a sintered raw material. At this time, carbonaceous material interior particles are mix | blended so that the mixture ratio with respect to a sintering raw material may become in the range of 10 mass% or more and 30 mass% or less. In addition, in this embodiment, the compounding rate with respect to the sintering raw material of carbonaceous material interior particle | grains is a value calculated by remove | dividing the mass of carbonaceous material interior particle | grains by the mass of a sintering raw material.
The sintering raw material in which the carbonaceous material interior particles are blended is carried into a surge hopper of a downward suction type sintering machine. The sintering raw material is charged into an endless moving pallet from the surge hopper, and a charging layer is formed. In the present embodiment, the carbonaceous material interior particles are blended so that the blending ratio with respect to the sintered raw material is within the range of 10% by mass or more and 30% by mass or less. By setting it as such a mixture ratio, the air permeability of the charging layer charged into the pallet can be improved. In order to further enhance the air permeability of the charging layer, the blending ratio of the carbonaceous material interior particles with respect to the sintered raw material is preferably in the range of 10% by weight to less than 30% by weight, and the blending ratio is 15% by weight or more. More preferably, the content is within the range of 25% by mass or less, and the blending ratio is more preferably 20% by mass.

  The charging layer is ignited by an ignition furnace installed on the upper side, and the charging layer is sequentially burned by sucking the upper gas downward from a window box installed on the lower side. The charge layer is sintered with combustion heat generated by the combustion to form a sintered cake. The sintered cake obtained in this manner is crushed and sized in the discharge portion, and agglomerates of about 5 mm or more are recovered as a product carbonaceous material-containing sintered ore. In this way, the carbonaceous material-containing sintered ore is produced, and the carbonaceous material-containing sintered ore is used as an ironmaking raw material for the blast furnace.

  As described above, the air permeability of the charging layer charged in the pallet is improved by mixing the carbonaceous material-containing particles so that the mixing ratio is within the range of 10% by mass to 30% by mass. Since the charging layer with improved air permeability is sintered in a shorter time compared with the charging layer with no improved air permeability, the carbonaceous material interior particles are adjusted so as to be within the range of the blending ratio described above. By blending, the productivity of the carbonaceous material-containing sintered ore can be improved. Moreover, since the manufacturing method of the carbonaceous material-containing sintered ore according to the present embodiment can be carried out using an existing sintering machine, no equipment cost for preparing a new sintering equipment is generated.

  Also, in the granulation step of the carbonaceous material interior particles, if the mixing ratio of the coke particles serving as the carbonaceous material core with respect to the total mass of the carbonaceous material interior particles is within the range of 1% by mass to 10% by mass, for example, a disk Conventional granulators such as pelletizers can be used as they are.

Next, the carbonaceous material-containing sintered ore will be described. In the carbon material-containing sintered ore manufactured by the method for manufacturing a carbon material-containing sintered ore according to the present embodiment, the carbon material and an iron source such as iron ore are arranged close to each other in the agglomerate. When the carbon material and the iron source are placed close together in the agglomerate, CO generated by the gasification reaction (endothermic reaction) on the carbon material side is used for the reduction reaction (exothermic reaction) on the iron source side, and the reduction reaction These reactions are repeated in a chain at a high rate inside the agglomerate, such that the CO ₂ generated in is used in the gasification reaction, so that the reduction efficiency is improved. Furthermore, if the carbonaceous material and the iron source are placed close to each other, the heat required for the gasification reaction is supplied by the reduction reaction of the iron source, improving the thermal efficiency and reducing the temperature at the top of the blast furnace without reducing the reduction efficiency. It can also be made. Thus, reduction efficiency can be improved and the temperature of a blast furnace upper part can be lowered | hung by using a carbonaceous material interior sintered ore as an iron-making raw material for blast furnaces.

  Sintering experiments were performed using a cylindrical sintering experiment apparatus (hereinafter referred to as a sintering pot) having an inner diameter of 300 mmφ × height of 400 mm. Pseudo particles are charged to a thickness of 400 mm in a sintering pot to form a charging layer, and the upper surface thereof is ignited by heating for 60 seconds using a burner using propane as a fuel. Suction was made at 700 mmAq to prepare a sintered cake.

In the sintering experiment, the temperature of the combustion exhaust gas discharged from the lower part of the sintering pan was measured, and the time from ignition to the time when this temperature reached the peak was taken as the sintering time. Moreover, after the sintering experiment was completed, the sintered cake was dropped once from a height of 2 m, and the sintered ore remaining on the sieve having an opening of 10 mm was defined as the product sintered ore. The product yield was calculated by dividing the mass of the product sintered ore of 10 mm or more by the mass of the sintered cake. Further, from the sectional area of the sintering pan (m ² ), the mass of the product sintered ore (t), and the sintering time (h), the unit hearth area (m ² ) and the unit time (h) The production rate (t / (h * m < ² >)) of the sintered ore which is a sintered ore production amount (t) was computed.

  Coke particles having a particle diameter of 2.8 mm or more and 4.75 mm or less obtained by sieving using a sieve conforming to JIS Z8801-1 were used as the coke particles serving as the carbon material core of the carbon material interior particles. Around this coke particle, granulated with a disk pelletizer so that the thickness of the mixed powder layer in which iron ore powder (150 μm or less) and quick lime are mixed is 5 mm, and the interior ratio of the carbonaceous material core is 97 mass% The carbonaceous material interior particle | grains which are are produced.

  On the other hand, ordinary granulated particles are mixed with ordinary powdered ore and auxiliary materials such as limestone, and powder coke having a particle size of 2.8 mm or less with water, and the arithmetic average particle size is 3 to 4 mm with a drum mixer. The raw material granulated to the extent was used. The arithmetic average particle size was calculated by measuring the weight of the granulated particles sieved into a plurality of particle size ranges and performing weighted averaging using the representative particle sizes in the respective particle size ranges.

  The normal agglomerated particles were mixed with the produced carbonaceous material interior particles to obtain a sintered raw material. The sintering raw material which changed the compounding ratio of the carbonaceous material interior particle | grains with respect to a sintering raw material was adjusted, and the sintering experiment was done using the said sintering raw material. Table 1 shows the conditions of the sintering experiment.

In each condition, and CaO contained in the carbonaceous material interior particles and pseudo particles were charged into the sintering pot, and SiO _2, and basicity, was adjusted with limestone and Keiseki to be constant. The other ingredients were considered as a consequence. Moreover, the powder coke was blended in the pseudo particles so as to be 5% by mass with respect to the mass sum of the carbonaceous material interior particles and the sintered raw material.

FIG. 2 is a graph showing the relationship between the carbonaceous material interior particle blending ratio, the charging density, and the air permeability. In the graph shown in FIG. 2, the horizontal axis represents the carbonaceous material interior particle content ratio (mass%), one vertical axis represents the charging density (dry-t / m ³ ), and the other vertical axis represents air permeability. (J · P · U index (−)). The charging density (dry-t / m ³ ) in FIG. 2 is the mass (t) of the sintering raw material from which moisture has been removed and charged into the charging pot, and the inner volume (m ³ ) of the sintering pot. The value divided by. The J · P · U index (−) is an index used for the evaluation of air permeability, and is an index calculated according to the method described in Non-Patent Document 1.

  As shown in FIG. 2, the charging density of the charging layer increased with the increase in the blending ratio of the carbonaceous material interior particles. On the other hand, the J · P · U index, which indicates the air permeability of the charging layer, improved to around 20% by mass with the increase in the mixing ratio of the carbonaceous interior particles, but further increased the mixing ratio of the carbonaceous interior particles. J / P / U index started to decrease. This is because the carbonaceous material-incorporated particles have a larger particle size than normal granulated particles, and the charged carbonaceous material-incorporated particles become air passages, and it is considered that the air permeability is improved up to a mixing ratio of about 20% by mass. . On the other hand, when the blending ratio exceeded 20% by mass, the air permeability decreased. This is because the carbon granulated particles dispersed in the charging layer cannot withstand the load in the layer due to a decrease in the melted normal granulated particles linking the carbonaceous material interior particles, and part of this collapses. This is considered to be because the carbon material interior particles were melted by the heat of combustion of the powdered coke which was blocked by the passage of air or increased by increasing the charging density. Furthermore, when the mixing ratio of the carbonaceous material interior particles exceeded 30% by mass, the air permeability of the charging layer was remarkably lowered.

FIG. 3 is a graph showing the relationship between the carbonaceous material interior particle content ratio, the cold strength, and the reducibility.
In the graph shown in FIG. 3, the horizontal axis represents the carbonaceous material interior particle blending ratio (mass%), one vertical axis represents the cold strength of the carbonaceous material-containing sintered ore: TI (%), and the other vertical axis. The axis is the reducibility of the carbonaceous material-containing sintered ore: RI (%). In addition, the cold intensity | strength in FIG. 3 was measured based on JISM8712, and the reducibility was measured based on JISM8713.

  As shown in FIG. 3, the cold strength indicating the strength of the carbonaceous material-containing sintered ore slightly decreased with an increase in the blending ratio of the carbonaceous material-containing particles. This is considered to be due to the improvement of the air permeability, but no significant reduction in cold strength was observed within the range of the mixing ratio of the carbonaceous material interior particles in this experiment. On the other hand, the reducibility increased with an increase in the blending ratio of the carbonaceous material interior particles. From this, it was confirmed that the reducibility of the carbonaceous material-containing sintered ore, which is an iron source, can be increased by increasing the blending ratio of the carbonaceous material-containing particles.

FIG. 4 is a graph showing the relationship between the blending ratio of carbonaceous material interior particles having a carbonaceous material core interior ratio of 97 mass%, 90 mass%, and 80 mass% and the sintered ore production rate. In the graph shown in FIG. 4, the horizontal axis represents the carbonaceous material interior particle blending ratio (mass%), and the vertical axis represents the carbonaceous material interior sintered ore production rate (t / (h × m ² )). In addition, the round plot is the result of the carbonaceous material interior particles having a carbonaceous material core interior rate of 97% by mass, and the triangular plot is the result of the carbonaceous material interior particle having the carbonaceous material nuclear interior rate of 90% by mass, and the square plot. These show the result of the carbonaceous material interior particle | grains whose carbon material core interior rate is 90 mass%.

  As shown in FIG. 4, regardless of the interior rate of the carbon material core, the production rate of the carbon material interior sintered ore was improved up to about 20% by mass with the increase in the blending rate of the carbon material interior particles. On the other hand, when the mixing ratio of the carbonaceous material interior particles exceeded 20% by mass, the production rate of the carbonaceous material interior sintered ore started to decrease. These tendencies are the same as the air permeability of the charging layer.

  Regardless of the presence or absence of carbonaceous material cores, the carbonaceous material interior particles have a larger particle size than ordinary granulated particles. For this reason, regardless of the presence or absence of the carbon material core, by mixing the carbon material interior particles so as to be within the range of the blending ratio described above, the charged carbon material interior particles become the air passageway and charged. It is thought that the air permeability of the layer was improved, and this could improve the productivity of the carbonaceous material-containing sintered ore. From these results, regardless of the interior rate of the carbon material core, by making the blending rate of the carbon material interior particles within the range of 10% by mass to 30% by mass, As a result, it was confirmed that the productivity of the carbonaceous interior sintered ore could be improved.

  Further, as shown in FIG. 4, the profile indicating the production rate of the carbonaceous material-containing sintered ore is an upwardly convex profile with the blending rate of the carbonaceous material-containing particles being around 20% by mass. For this reason, in order to increase the productivity of the carbonaceous material-containing sintered ore, it is preferable that the mixing rate of the carbonaceous material-containing particles is within a range of 10% by mass or more and less than 30% by mass, and the mixing rate is 15% by mass. It can be seen that the content is more preferably in the range of 25% by mass or less, and the blending ratio is more preferably 20% by mass.

  Thus, the carbonaceous material-containing sintered ore according to the present embodiment using the sintered raw material in which the carbonaceous material-containing particles are blended so that the blending ratio with respect to the sintered raw material is in the range of 10% by mass to 30% by mass. Sintering experiments confirmed that by implementing the manufacturing method, a highly reducible carbonaceous material-containing sintered ore that can improve the reduction efficiency can be manufactured with high productivity.

Claims (2)

Carbonaceous material interior particles in which an outer layer made of a raw material containing iron ore powder and CaO is formed around the carbonaceous material core, iron sources such as iron ore and dust, auxiliary materials, powdered coke, anthracite, etc. A carbonaceous material-containing sintered ore that produces sintered ore by charging a sintered raw material mixed with granulated particles that are mixed and granulated into a pallet of a downward suction type sintering machine A manufacturing method of
The blending ratio of the carbonaceous material decorated particles to sintering raw material state, and are within the range of 10% by weight to 30% by weight,
A method for producing a carbonaceous material-containing sintered ore , wherein the carbonaceous material-containing particles have a particle size of 5 mm or more and are larger than the granulated particles .   2. The method for producing a carbon material-containing sintered ore according to claim 1, wherein a blending ratio of the carbon material-containing particles with respect to the sintered raw material is in a range of 15% by mass or more and 25% by mass or less.