JP5365044B2 - Ferro-coke manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel method for efficiently producing ferro coke considering improvement of a molding yield in a molding process for agglomeration of raw materials. <P>SOLUTION: When ferro coke is produced by carbonizing a molded material prepared by molding a molding raw material containing coal 20, an iron source raw material 21 and a binder, the molded material after molding is sieved by a sieve 3 to separate a ferro coke producing molded material and a powder portion from each other, and the ferro coke producing molded material is carbonized by a carbonization furnace 4, while the powder portion is conveyed by a powder portion conveying line 7 to be used as the molding raw material of the molded material. Preferably, the grain size of the powder portion is 6 mm or less, 3-15 mass% of the powder portion is used as the molding raw material based on the total amount of the coal and the iron source raw material, and the molded material is molded by using a double-roll molding machine 2. <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 (see, for example, Patent Document 1). Whether the ferro-coke raw material has a coal-rich composition ratio or an iron ore-rich composition ratio is arbitrarily determined depending on whether it is intended to replace coke or is used as an iron source.

In the process of manufacturing this ferro-coke, it is necessary to agglomerate coal and iron ore with a molding machine. The agglomeration method includes adding a binder to the raw material and molding at room temperature, and softening and melting coal at a high temperature of 250 ° C. or higher, and molding using the caking property of the coal without adding the binder There is. As the former method, a method is known in which coal, iron ore and a binder are kneaded with a kneader and then molded at room temperature (for example, see Patent Document 2). As the latter method, there is known a method in which coal and iron ore are mixed, rapidly heated to 250 ° C. or higher and press-molded (see, for example, Patent Document 3). The agglomerated molded product is carbonized in a carbonization furnace to produce ferrocoke.
JP 2005-15700 A (Claims) JP-A-64-81889 (Page 2) Japanese Patent Laying-Open No. 2005-53986 (Claim 3)

  As described above, the production of ferro-coke includes a molding step in which raw materials are agglomerated and a step in which ferro-coke products are obtained by dry distillation of the agglomerated molded product. When manufacturing ferro-coke, it is required that the strength of the molded product after agglomeration is high and that the product strength of ferro-coke after dry distillation is high because it is put into a blast furnace. The molding yield in the process is important. However, in Patent Documents 1 to 3 described above, the temperature to be molded, the type of raw material to be used, and the auxiliary raw materials have been studied, but no consideration has been given to the molding yield.

  Therefore, an object of the present invention is to provide an efficient new ferro-coke production method in consideration of improvement in molding yield in a molding process for agglomerating raw materials.

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 molded product after molding is sieved and separated into a molded product for ferrocoke production and a powdered part, the molded product for ferrocoke production is dry distilled, and the powdered part is used as a raw material for molding the molded product. A method for producing ferro-coke, characterized by being used.
(2) The method for producing ferro-coke according to (1), wherein the particle size of the powdery part is 6 mm or less.
(3) Ferro according to (1) or (2), wherein a powdery part of 3% by mass to 15% by mass is used as a raw material for molding with respect to the total amount of coal and iron source material. Coke production method.
(4) The method for producing ferro-coke according to any one of (1) to (3), wherein a molded product is molded using a double roll molding machine.

  According to the present invention, since the powdery part is removed from the molded product before dry distillation, there is no raw material that becomes waste coal or waste ore, and efficient ferro-coke can be produced in consideration of improvement in molding yield. .

  Moreover, by performing double roll molding, separation of the powdery part from the molded product is facilitated, sieving efficiency is improved, and efficient molding can be performed.

  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 20 and the iron source material 21 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. As the iron source material 21, iron ore is mainly used, but instead of the iron ore, an iron source material that is produced as a by-product without ironworks such as blast furnace dust, converter dust, and rolling sludge may be used. In this embodiment, iron ore is used as the iron source material 21.

  The blended coal and iron ore are put into the stirrer 1. A binder is added to the stirrer 1 from a binder tank 5. 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 8 in which a forming raw material is charged, and a stirring blade 9 provided inside the container main body 8 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 9 that rotates at a higher speed than a screw stirrer. A jacket 10 into which high-temperature oil or high-pressure steam flows is provided as a heating unit around the container body 8. The jacket 10 heats the container body 8 so that the molding raw material is in the range of 120 ° C to 240 ° C. The mixed raw material obtained by stirring is discharged from the discharge unit 11.

  The binder is added from the binder tank 5 at the same time as charging the stirrer 1 with coal and iron ore 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 12 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 12. FIG. 4 shows a perspective view of the forming roll 12. As shown in FIG. 4, a recess 13 is formed on the outer peripheral surface of the molding roll 12, and a molded product 22 having the shape of the recess 13 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 separated by a sieve 3 into a ferro-coke production molding and a powdery part (unmolded product), and the ferro-coke production on the sieve. The molded product is conveyed from the ferro-coke production molded product conveyance line 6 to the dry distillation furnace 4 in the next step. When the powdery part (unmolded material) under the sieve is transported to the dry distillation furnace 4, it causes racking of the charge in the dry distillation furnace or causes the air permeability in the dry distillation furnace to deteriorate. It interferes with the dry distillation process. Therefore, in the present invention, the powdery part is conveyed from the powdery part conveyance line 7 to the stirrer 1 and reused as a forming raw material. By reusing the powdery part of the molded product as a raw material for molding, the apparent molding yield becomes 100% and efficient molding can be realized. Although the sieve mesh of the sieve 3 is not particularly limited, a sieve mesh in which the molded product for producing ferrocoke remains on the sieve is preferable, and the size varies depending on the molding size of the molded product. Preferably, a sieve with a particle size of 10 mm or less is sieved, more preferably a sieve with a powdery part with a particle size of 6 mm or less is sieved.

  The powdery portion of the molded product that is reused as the molding material is added to the stirrer 1, and the amount added is about 3 to 15% by mass, preferably 5 to 12%, based on the coal 20 and the iron source material 21. It is about mass%. If the addition amount of the powdery part is less than 3% by mass with respect to the coal and iron source material, the remaining amount of the powdery part increases, and it takes time to re-add as a raw material for molding. As a result, the temperature of the powdery part decreases and the powdery part becomes solid together with the binder, and a new process such as pulverization is required for re-addition. Therefore, the molding process cannot be performed efficiently. On the other hand, when the addition amount of the powdery part is more than 15% by mass with respect to the coal and the iron source material, the handling strength of the molded product is lowered and more binder is required, which is not preferable.

  As an efficient molding method for improving the molding yield, ferro-coke was experimentally produced and its quality was evaluated in order to reuse the powdery part of the molded product as a raw material for molding.

  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 the 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 raw material was molded into a 6 cm ³ molded product by a double roll molding machine. The molded product was sieved into a ferro-coke manufacturing molded product and a powdery part with a 6 mm sieve, and the ferro-coke manufacturing molded product on the sieve was subjected to carbonization at a carbonization temperature of 900 ° C. for 2 hours to obtain ferro-coke (powdered) Equivalent to 0% by weight of part).

  Next, sieving is performed immediately after molding, and the powdery part obtained as the sieving is immediately 5% by mass, 10% by mass, 15% by mass with respect to the total amount of coal and iron ore among the raw materials for molding, 20% by mass was added and molded in the same manner as described above. Similarly, the molded product was carbonized at a carbonization temperature of 900 ° C. for 2 hours to obtain ferrocoke.

  In each case, the strength of the molded product and the strength of the ferro-coke were measured using an I-type 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. 5 shows the strength of the molded product, and FIG. 6 shows the measurement results of the ferro-coke strength after dry distillation.

  According to FIG. 5, the strength of the molded product obtained by adding the powdery part of the molded product to the raw material for molding tends to slightly decrease with the addition amount of the powdery part, compared with 15% by mass. It turns out that it is enough as handling intensity until. Moreover, according to FIG. 6, as for the ferro-coke intensity | strength after dry distillation, it turns out that an intensity | strength fall is large in what added 20 mass% of powdery parts similarly to molded object intensity | strength.

  Furthermore, using the powdery part sieved from the molded product as a raw material for molding, 2 hours after molding the molded product, 5% by mass, 10% by mass with respect to the total amount of coal and iron ore in the raw material for molding 15% by mass and 20% by mass were added and molded in the same manner as described above. FIG. 7 shows the strength of the molded product measured in the same manner as described above.

  According to FIG. 7, when the powdery part 2 hours after molding is added, the decrease in strength is greater than that of the powdery part added immediately after molding. This is presumably because the molding raw material once compacted by the molding machine is cooled together with the binder and charged as an agglomerate into the stirrer, so that the molding raw material becomes non-uniform and the dispersibility of the binder deteriorates.

  As described above, by using a predetermined amount of the powdered portion of the molded product immediately after molding as a molding raw material, the apparent molding yield can be improved and efficient molding can be performed. As a result, the raw material is not wasted and the manufacturing cost can be reduced.

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. The graph which shows the influence of the addition amount of the powdery part which acts on the intensity | strength of a molding (immediately after shaping | molding). The graph which shows the influence of the addition amount of the powdery part on the intensity | strength of ferro-coke. The graph which shows the influence of the addition amount of the powdery part which acts on the intensity | strength of a molding (2 hours after shaping | molding).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High-speed stirrer 2 Double roll molding machine 3 Sieve 4 Dry distillation furnace 5 Binder tank 6 Molded material conveyance line for ferro-coke production 7 Powdery part conveyance line 8 Container body 9 Stirring blade 10 Jacket 11 Discharge part 12 Molding roll 13 Depression 20 Coal 21 Iron source material 22 Molded product

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,
The molded product after molding is sieved and separated into a molded product for ferrocoke production and a powdery part,
Carbonizing the molded product for ferro-coke production,
Method for producing a ferro-coke, which comprises using the total amount of the iron source material and the coal, the powder portion in the 3 to 15 wt% as before KiNaru type raw material.   The method for producing ferro-coke according to claim 1, wherein the particle size of the powdery part is 6 mm or less. The method for producing ferro-coke according to claim 1 or 2 , wherein a molding is molded using a double roll molding machine.

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