JP5365043B2 - Ferro-coke manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel method for producing ferro coke for preventing deformation or thermal cracking of a molded product in a carbonization process and improving an original form yield on the carbonization furnace outlet side and handling strength in production of ferro coke. <P>SOLUTION: When ferro coke is produced by carbonizing a molded material prepared by molding a molding raw material containing coal 30, an iron source raw material 31 and a binder, a carbonized molded material is sieved by a sieve 4 to separate a product ferro coke and coke powder containing metallic iron from each other, and the coke powder containing the metallic iron is used as the molding raw material of the molded material. Preferably, the grain size of the coke powder containing the metallic iron is 6 mm or less, 0.5-8 mass% of the coke powder is used based on the total amount of the coal 30 and the iron source raw material 31, and the molded material is carbonized by using a vertical shaft kiln 3. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a ferro-coke manufacturing method for manufacturing ferro-coke for metallurgy using iron source materials such as iron ore and coal as raw materials.

  In order to efficiently operate the blast furnace, coal is carbonized in a coke oven to produce coke, and the coke is thrown into the blast furnace. Coke in the blast furnace has a role of a spacer for improving ventilation in the blast furnace, a role as a reducing material, a role as a heat source, and the like. In recent years, from the viewpoint of improving the reactivity of coke, a technique for obtaining ferro-coke for metallurgy by mixing iron ore with coal is known.

  As a technology for producing ferro-coke by dry distillation in a normal chamber furnace coke oven using iron source materials such as iron ore and coal as raw materials, (a) a mixture of coal and fine iron ore is used as a chamber furnace coke. A method of charging into a furnace, (b) a method of forming coal and iron ore cold, that is, at room temperature, and charging the molded product into a chamber-type coke oven have been studied (for example, non-patent literature). 1). However, since ordinary furnace-type coke ovens are composed of silica brick, when iron ore is charged, iron ore reacts with silica, which is the main component of silica brick, and a low melting point firelight is produced. Cause damage to the quartz brick. For this reason, the technique which manufactures ferro-coke by a chamber furnace type coke oven is not implemented industrially.

  In recent years, a continuous molding coke manufacturing method has been developed as a coke manufacturing method replacing the chamber furnace coke manufacturing method. In the continuous molding coke manufacturing method, a vertical shaft furnace composed of chamotte bricks instead of silica bricks is used as a carbonization furnace, coal is molded into a predetermined size in the cold, and then charged into the shaft furnace. The coal is carbonized by heating using a circulating heat medium gas to produce a molded coke. It has been confirmed that even if a large amount of non-slightly caking coal that is abundant in resource reserves and inexpensive is used, it is possible to produce coke that has the same strength as a normal chamber-type coke oven. When the caking property is high, the coal is softened and fused in the shaft furnace, which makes it difficult to operate the shaft furnace and causes deterioration of coke quality such as deformation and cracking.

  In order to suppress fusion in the shaft furnace in the continuous molding coke manufacturing method, iron ore is added to the coal so as to be 15 to 40% by mass of the total amount, and the molded product is manufactured cold, and the shaft A method of charging into a furnace has been proposed (see, for example, Patent Document 1). In this method, since iron ore is not caustic, it is necessary to add a large amount of binder in order to produce a molded product in a cold state, and a lump molded product in a heated state in which coal and iron ore are heated. There has also been proposed a method of molding into (see, for example, Patent Document 2).

When heat-treating a mixture of coal and iron ore as described above to produce molded coke (ferro-coke), in order to suppress deterioration of coke quality such as deformation and cracking, Thus, an optimum heating rate design method according to the temperature of the molded product has been proposed (see, for example, Patent Document 3 and Patent Document 4).
Fuel Association "Coke Technology Annual Report" 1958, p. 38 JP-A-6-65579 JP 2004-217914 A JP-A-52-23103 JP-A-7-102260

  As described above, the production of ferro-coke includes a molding process for agglomeration and a process for obtaining a ferro-coke product by dry distillation of the agglomerated molded product. When manufacturing ferro-coke, suppressing deformation and thermal cracking of the molded product in the carbonization process is an important issue because it increases the yield of the original shape on the exit side of the carbonization furnace and also improves the handling strength.

  Therefore, the object of the present invention is to solve such problems of the prior art and suppress deformation and thermal cracking of the molded product in the dry distillation process when producing ferro-coke, and the original yield on the outlet side of the dry distillation furnace, handling strength. It is an object to provide a new ferro-coke manufacturing method capable of improving the quality.

The features of the present invention for solving such problems are as follows.
(1) When producing a ferro-coke by dry-distilling a molding obtained by molding a molding raw material containing coal, an iron source raw material and a binder,
The ferro-coke of the ferro-coke is characterized in that the molded product obtained by dry distillation is sieved and separated into product ferro-coke and coke powder containing metallic iron, and the coke powder containing metallic iron is used as a raw material for molding the molded product. Production method.
(2) The method for producing ferro-coke as described in (1), wherein the particle size of the coke powder containing metallic iron is 6 mm or less.
(3) Coke powder containing 0.5% by mass to 8% by mass of metallic iron with respect to the total amount of coal and iron source material is used as a molding material (1) or (2) ) The manufacturing method of the ferro-coke as described in.
(4) The method for producing ferro-coke according to any one of (1) to (3), wherein the molded product is subjected to dry distillation using a vertical shaft furnace.

  According to the present invention, by using coke powder containing metallic iron as a raw material for molding, it is suppressed that the carbonaceous material is used for reduction of iron ore due to an increase in the reduction rate in the dry distillation process, and is generated in ferro-coke. It is possible to suppress the defect structure that occurs, and to prevent a decrease in strength after dry distillation.

  In addition, carbonization using a vertical shaft furnace enables continuous carbonization unlike the normal chamber furnace coke production method.Furthermore, when any trouble occurs, emergency stop is possible, and the operation method is Flexibility arises.

  Furthermore, since the product ferro-coke has the powdery part removed, the air permeability in the blast furnace can be maintained well.

  Hereinafter, an embodiment of a method for producing ferro-coke of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a ferro-coke manufacturing facility. The coal 30 and the iron source material 31 are pulverized to a predetermined particle size or less by a pulverizer (not shown), and then blended at a predetermined ratio. For example, coal is crushed to 3 mm or less, and iron source material is crushed to 0.5 mm or less. And it mix | blends in the ratio of 60-90 mass% of coal, and 10-40 mass% of iron source raw materials, for example. Although iron ore is mainly used as the iron source material 31, iron source materials that are by-produced in the ironworks such as blast furnace dust, converter dust, and rolling sludge may be used instead of iron ore. In the present embodiment, iron ore is used as the iron source material 31.

  The blended coal and iron ore are put into the stirrer 1. A binder is added to the stirrer 1 from a binder tank 6. As the binder, SOP (soft pitch), medium pitch, PDA (propane desulfurized asphalt), ASP (asphalt pitch), or the like, which are usually used, are used, and one kind or two or more kinds can be used in combination.

  FIG. 2 shows the agitator 1 portion in more detail. The stirrer 1 includes a container main body 9 in which a forming raw material is charged, and a stirring blade 10 provided inside the container main body 9 for stirring the forming raw material. Considering the dispersibility of coal and iron ore, it is desirable to use a stirrer 1 that stirs with a stirring blade 10 that rotates at a higher speed than a screw stirrer. A jacket 11 through which high-temperature oil or high-pressure steam flows is provided as a heating unit around the container body 9. The jacket 11 heats the container body 9 so that the molding material is in the range of 120 ° C to 240 ° C. The mixed raw material obtained by stirring is discharged from the discharge unit 12.

  The binder is added from the binder tank 6 at the same time that the coal and iron ore are charged into the stirrer 1 or during stirring.

  As shown in FIG. 1, the mixed raw material discharged from the stirrer 1 is high-pressure molded by a double roll molding machine 2 which is a high-pressure molding machine. The double roll molding machine 2 molds the mixed raw material immediately after discharging from the stirrer 1. For this reason, the molding temperature of the double roll molding machine 2 is close to the stirring temperature of the stirrer 1. The double roll molding machine 2 itself does not necessarily have a heating mechanism.

FIG. 3 shows the double roll molding machine 2 in more detail. The double roll molding machine 2 has a pair of molding rolls 13 that rotate in directions opposite to each other, and the mixed raw material is pressure-molded at a contact point between the pair of molding rolls 13. FIG. 4 is a perspective view of the molding roll 13. As shown in FIG. 4, a recess 14 is formed on the outer peripheral surface of the molding roll 13, and a molding 32 having the shape of the recess 14 is molded. The size of the molded product is not particularly limited, and is about ³ to 95 cm ³ , preferably about 6 to 60 cm ³ . The required molding size varies depending on the state of use in the blast furnace.

  As shown in FIG. 1, the molded product molded by the double roll molding machine 2 is dry-distilled in the vertical shaft furnace 3 and discharged from the lower part of the vertical shaft furnace 3. Although the discharge method is not particularly limited, it is necessary to cool to a sufficiently low temperature so as not to undergo reoxidation in the lower part of the furnace because the ferro-coke that has been carbonized contains metallic iron. Or it is preferable to cool to about 80 degreeC by nitrogen atmosphere. The carbonized ferro-coke is discharged from the lower part of the vertical shaft furnace 3 and separated into ferro-coke and coke powder containing metallic iron by the sieve 4, and the sieve is stored as a product ferro-coke from the ferro-coke conveyance line 7 in the storage tank. 5 is conveyed. Coke powder containing metallic iron under sieving may deteriorate air permeability in the furnace when it is transported into the blast furnace, which may hinder blast furnace operation. Therefore, in the present invention, coke powder containing metallic iron is conveyed from the coke powder conveyance line 8 to the stirrer 1 and reused as a forming raw material. By reusing coke powder containing metallic iron as a raw material for forming ferro-coke, deterioration of air permeability in the blast furnace can be suppressed and the strength of ferro-coke can be improved. When coal and iron ore moldings are carbonized, as the carbonization proceeds, the carbonaceous material is used to reduce the iron ore and the iron ore reduction rate increases, resulting in a defective structure in the ferro-coke. In the present invention, the coke powder containing metallic iron generated during dry distillation is reused as a raw material for molding, so that the molded product contains a predetermined amount of metallic iron from the beginning. Therefore, it is possible to suppress the defect structure generated in the ferro-coke. Although the sieve mesh of sieve 4 is not particularly limited, a sieve mesh in which ferrocoke that can be used as a product remains on the sieve is preferable, and the size varies depending on the molding size of the molded product. Preferably, the sieve is such that the particle size is 10 mm or less, and more preferably the unmolded product having a particle size of 6 mm or less is the sieve.

  Coke powder containing metallic iron that is reused as a forming raw material is added to the stirrer 1, and the addition amount is about 0.5 to 8% by mass, preferably 1 with respect to the coal 30 and the iron source raw material 31. About 5% by mass. When the amount of coke powder containing metallic iron is less than 0.5% by mass relative to the coal and iron source material, there is no effect of adding metallic iron, and the same results as ferro-coke produced with a molded product of only coal and iron ore It becomes. On the other hand, when the amount of coke powder containing metallic iron is more than 8% by mass, the handling strength of the molded product when it is produced with the same binder addition amount is lowered, and the ferro-coke strength after dry distillation may be lowered, which is not preferable. .

  Ferro-coke was experimentally manufactured and its quality was evaluated in order to suppress deformation and thermal cracking of the molded product in the carbonization process and to improve the original yield and handling strength on the exit side of the carbonization furnace.

  Ferro-coke was produced by the following method. First, the raw material for ferro-coke was adjusted, and the coal was adjusted to a particle size of 3 mm or less (-3 mm) with a jaw crusher, and this coal was adjusted to a particle size of 0.5 mm or less (-0.5 mm) with a roll mill. The pulverized iron ore was blended at a ratio of 30% by mass. Coal blended with 50 wt% each of cohesive coal (Coal 1) with an average maximum reflectance of 0.70% and non-coking coal (Coal 2) with an average maximum reflectance of 1.70% was used. . Carajas ore was used as iron ore. Table 1 shows the properties of iron ore and Table 2 shows the properties of coal.

The above coal and iron ore were charged into a stirrer, heated and stirred, and 5% by mass of soft pitch was added immediately before the raw material was discharged. Furthermore, stirring was continued and the mixed raw material was discharged at 180 ° C. The discharged mixed raw material is molded into a 6 cm ³ molded product by a double roll molding machine, and charged from the upper part of the electric resistance heating vertical distillation furnace equipped with a hot air heating furnace shown in FIG. For about 3 hours to obtain ferro-coke (corresponding to 0 mass% added metal iron-containing coke powder).

  Next, dry-distilled ferro-coke is sieved into 6-mm sieve sieves into bulk ferro-coke and coke powder containing metallic iron, and the coke powder containing metallic iron is the total amount of coal and iron ore among the raw materials for molding. On the other hand, 0.5% by mass, 5% by mass, 8% by mass, and 12% by mass were added and molded in the same manner as described above. Similarly, the molded product was carbonized at a maximum temperature of 900 ° C. for about 3 hours to obtain ferro-coke.

  In each case, the strength of the molded product and the strength of the ferro-coke were measured using a type I drum test apparatus (cylindrical shape having an inner diameter of 130 mmΦ × 700 mm). At a rotational speed of 20 revolutions per minute, the strength of the molded product is 6 mm or more after 30 revolutions (DI30 / 6). For ferro-coke, the residual rate after 6 revolutions is 6 mm or more. The strength was evaluated according to (DI600 / 6). FIG. 6 shows the strength of the molded product, and FIG. 7 shows the measurement results of the strength of ferro-coke.

  According to FIG. 6, the strength of a molded product obtained by adding coke powder containing metallic iron and molding tends to slightly decrease with an increase in the amount of addition compared to a molded product without addition, but up to 8% by mass. It can be seen that the handling strength is sufficient. In addition, according to FIG. 7, the ferro-coke strength after dry distillation tends to improve when the amount of coke powder containing metallic iron is up to 5% by mass, and the strength equivalent to that without addition when 8% by mass is added. It turns out that it is.

  As described above, by reusing the coke powder containing metallic iron produced in the dry distillation process of ferro-coke production as a raw material for molding, deformation and thermal cracking of the molded product in the dry distillation process are suppressed, It was found that the original yield and the handling strength can be improved.

Schematic which shows the manufacturing equipment of ferro-coke. Explanatory drawing of a stirrer part. Explanatory drawing of a double roll molding machine. The perspective view of the forming roll of a double roll forming machine. Explanatory drawing of the electrical resistance heating type vertical dry distillation furnace provided with the hot air heating furnace. The graph which shows the influence of the amount of metal iron containing coke powder addition on the intensity | strength of a molding. The graph which shows the influence of the amount of metal iron containing coke powder additions on the strength of ferro-coke.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High-speed stirrer 2 Double roll molding machine 3 Vertical shaft furnace 4 Sieve 5 Storage tank 6 Binder tank 7 Ferro-coke conveyance line 8 Coke powder conveyance line 9 Container body 10 Stirring blade 11 Jacket 12 Discharge part 13 Molding roll 14 Depression 15 Electric furnace 16 Hot Blast Furnace 17 Reaction Tube 18 Bucket Conveyor 19 Tarpot 20 Combustion Furnace 21 Molded Material Charge 22 Ferro Coke Discharge 23 Furnace Top Gas 30 Coal 31 Iron Source Raw Material 32 Molded Material

Claims (3)

When producing ferro-coke by dry-distilling a molded product obtained by molding a molding material containing coal, iron source material and binder,
Sieving the dry-molded molding, separating it into product ferro-coke and coke powder containing metallic iron,
The total amount of the iron source material and the coal, the production method of Ferro coke which comprises using coke powder containing the metal iron 0.5-8% by weight as before KiNaru type raw material.   The method for producing ferro-coke according to claim 1, wherein the particle size of the coke powder containing metallic iron is 6 mm or less. The method for producing ferro-coke according to claim 1 or 2 , wherein the molded product is subjected to dry distillation using a vertical shaft furnace.

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