JP2016176037A - Method for producing ferrocoke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method where raw material containing coal, an iron source raw material and a binder is molded, and the molded part is carbonized to produce ferrocoke, where high molding strength and product strength are secured while suppressing the using amount of an expensive binder.SOLUTION: Provided is a method for producing ferrocoke containing: a step A where, as binders, a high softening point binder a1 having a softening point of 150°C or higher and a low softening point binder a2 having a softening point below 100°C and coal are produced by a carbonization step, and, while heating raw material containing tar a3 having a softening point lower than that of the low softening point binder a2, kneading is performed; a step B where the raw material passed through the step A is molded into a molded part; and a step C where the molded part obtained in the step B is carbonized into ferrocoke. In the step A, the tar a3 having low viscosity is preferentially infiltrated into the fine pores of the coal and iron ore, thus the amount of the low softening point binder a2 infiltrated into the fine pores is reduced, and the low softening point binder a2 suitably exhibits its binder function.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for producing ferro-coke, and more particularly, to a method for producing ferro-coke by molding a raw material containing coal, an iron source raw material and a binder, and subjecting the molded product to dry distillation.

  In blast furnace operation, metallurgical coke produced by carbonizing coal in a coke oven is generally used. Metallurgical coke 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 or effectively using the iron source in iron ore, a technology has been developed to obtain ferro-coke for metallurgy by dry distillation of a raw material mixed with coal and iron ore. As a method for producing ferro-coke, a method is known in which a raw material in which coal and iron ore are mixed is molded into a lump shape, and the molded product is subjected to carbonization in a carbonization furnace. In this manufacturing method, the raw material is molded into a lump by (i) a method in which a binder is added to the raw material, and (ii) without adding a binder, the coal in the raw material is softened and melted at a high temperature of 250 ° C. or higher. There is a method in which the raw material is hot molded using the cohesiveness of the coal.

  Here, in the above method (ii), in order to form a mixture of coal and iron ore in a hot state, it is necessary to use coal with high caking properties, and the molding is performed while heating. Therefore, the molding itself is not easy due to the influence of the generated gas. Therefore, it is considered desirable to reduce the amount of binder used as much as possible by adopting the above-mentioned method (i), which can form the raw material using not only highly caking coal but also ordinary coal. However, when the amount of the binder used is simply reduced by the method (i), there is a problem that the strength of the molded product and the product strength of the ferrocoke produced from this molded product are lowered.

  To such a problem, Patent Document 1 discloses a high softening point binder having a softening point of 150 ° C. or higher as a binder to be blended with a raw material in order to increase the handling strength of a molded product and the product strength of ferrocoke. A method has been proposed in which a low softening point binder having a softening point of less than 150 ° C. is used, and the raw material is stirred while being heated in the range of 120 ° C. to 240 ° C. and then molded. In this method, asphalt pitch (ASP) or the like is used as the high softening point binder, and soft pitch (SOP) or the like is used as the low softening point binder.

JP 2007-277489 A

  However, there are cases where the required molded product strength and product strength cannot be obtained only by using a high softening point binder and a low softening point binder together as in Patent Document 1. In particular, when inferior coal or iron ore with many fine pores is used, sufficient molding strength and product strength cannot be obtained unless a large amount of binder is added. Since the binder used in Patent Document 1, particularly a low softening point binder such as a soft pitch, is expensive, there is a problem that the manufacturing cost increases.

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, in a method for forming a ferro-coke by molding a raw material containing coal, an iron source raw material and a binder, and subjecting the molded product to dry distillation. An object of the present invention is to provide a ferro-coke production method capable of producing a high-quality ferro-coke having a high product strength while the molded product after molding has a sufficient handling strength while suppressing the amount of binder used.

  As a result of repeated experiments and studies in order to solve the above problems, the present inventors have produced, as a binder, together with a high softening point binder and a low softening point binder in the process of dry distillation of coal, rather than a low softening point binder. By using tar with a low softening point, preferably by adding these three types of binders to the raw material in a specific order and heating and mixing, while suppressing the amount of expensive binders (especially low softening point binders) used, It has been found that the handling strength of a molded product after molding and the product strength of ferrocoke produced from this molded product can be effectively expressed.

The present invention has been made on the basis of such knowledge and has the following gist.
[1] In a method for producing a ferro-coke by molding a raw material containing coal, an iron source raw material and a binder, and subjecting the molded product to dry distillation, as a binder, a high softening point binder (a1) having a softening point of 150 ° C. or higher, Kneading while heating a raw material containing a low softening point binder (a2) with a softening point of less than 100 ° C and tar (a3) produced in the process of carbonizing coal and having a softening point lower than that of the low softening point binder (a2) A step (A) to perform, a step (B) to mold the raw material after the step (A) to form a molded product, and a step to dry-distill the molded product obtained in the step (B) to form ferro-coke ( A method for producing ferro-coke, which comprises C).

[2] In the production method of [1] above, when the raw materials are kneaded while heating in the step (A), the coal, the iron source raw material, and the high softening point binder (a1) are first kneaded, and this kneaded raw material A method for producing ferro-coke, characterized by adding tar (a3) to kneading, and further kneading the kneaded raw material with a low softening point binder (a2).
[3] In the production method of [2] above, when kneading while heating the raw material in the step (A), first, the coal, the iron source raw material and the high softening point binder (a1) are kneaded, and this kneaded raw material In addition, tar (a3) is added and kneaded in a range where the raw material temperature is 100 ° C. or higher and lower than 130 ° C., and the raw material temperature is 130 ° C. or higher and [raw material discharge temperature−30 ° C.] A method for producing ferro-coke, which comprises adding and kneading a low softening point binder (a2) within a range of [raw material discharge temperature −10 ° C.].

[4] In the production method of [1] above, when the raw materials are kneaded while heating in the step (A), the coal, the iron source raw material, and the high softening point binder (a1) are first kneaded, and this kneaded raw material A method for producing ferro-coke, which comprises adding a low softening point binder (a2) and tar (a3) and kneading.
[5] In the production method of [4] above, when the raw materials are kneaded while heating in the step (A), the coal, the iron source raw material and the high softening point binder (a1) are first kneaded, and this kneaded raw material In contrast, the low softening point binder (a2) and tar (a3) are added and kneaded in a range of the raw material temperature of 120 ° C. or higher and [raw material discharge temperature −10 ° C.] to [raw material discharge temperature −30 ° C.]. The manufacturing method of the ferro-coke characterized by these.

[6] In the production method according to any one of [1] to [5], the tar (a3) is a ferro-coke tar produced in a dry distillation step when producing ferro-coke. Production method.
[7] The method for producing ferro-coke according to the above-mentioned [6], wherein the ferro-coke tar is produced in the step (C).
[8] In the production method of any one of [1] to [7] above, the raw material kneaded while heating in step (A) is discharged from the kneader at a raw material temperature of 150 to 170 ° C. A method for producing ferro-coke, which is formed into a molded product by molding in B).
[9] The method for producing ferro-coke according to any one of the above [1] to [8], wherein in the step (C), the molded product is subjected to carbonization in a vertical carbonization furnace.

  According to the present invention, a high softening point binder (a1) and a low softening point binder are used as binders in a method for producing ferrocoke by molding a raw material containing coal, an iron source raw material and a binder, and subjecting the molded product to dry distillation. Along with (a2), by using low-viscosity tar (a3) produced in the process of carbonizing coal and having a lower softening point than low softening point binder (a2), the amount of expensive binders such as low softening point binders used While suppressing the above, it is possible to stably produce a high-quality ferro-coke having a high product strength while the molded product after molding has sufficient handling strength.

  In addition, ferro-coke tar produced in the dry distillation process when producing ferro-coke has many low molecular weight components and low viscosity, so when used alone, the performance as a binder is inferior. Therefore, it is difficult to produce pitch and the like by refining and must be treated as industrial waste. In the present invention, this ferro-coke tar is used as a low-viscosity tar (a3). By using, ferro coke tar can be effectively used. Moreover, there is an advantage that the ferro-coke tar generated when the ferro-coke is produced by the production method of the present invention can be reused as a part of the binder, and the produced ferro-coke tar can be reused in a self-contained manner in the system.

In the present invention, an explanatory view schematically showing the principle that the binder effect by the low softening point binder a2 is improved by adding the low-viscosity tar a3 as a part of the binder. The graph which shows the viscosity in 70-140 degreeC of the soft pitch which is the low softening point binder a2, and the ferro coke tar which is the low-viscosity tar a3. Explanatory drawing which shows typically one Embodiment of this invention using the ferro-coke manufacturing equipment and this manufacturing equipment Explanatory drawing which shows the measuring method of the softening point of a binder Explanatory drawing which shows typically one Embodiment of the kneading machine used by this invention Explanatory drawing which shows typically one Embodiment of the molding machine used by this invention FIG. 7 shows a pair of molding rolls constituting the molding machine shown in FIG. 6. FIG. 7 (a) is a perspective explanatory view, and FIG. 7 (b) is an explanation showing molding pressure applied to a contact point of the pair of molding rolls. Figure

  The present invention is a method for producing a ferro-coke by molding a raw material containing coal, an iron source raw material and a binder, and subjecting the molded product to dry distillation. In this method, the softening point is 150 ° C. as a binder to be added to the raw material. The above-mentioned high softening point binder (a1), a low softening point binder (a2) having a softening point of less than 100 ° C., and a tar with a softening point lower than that of the low softening point binder (a2) (a2). It is characterized by using three kinds of binder components a3). In the present invention, by using the tar (a3) as a part of the binder, the low softening point binder (a2) can have a function (binder function) commensurate with the amount added, resulting in an expensive low softening. While reducing the amount of the point binder used, the ferro-coke having a high product strength can be produced while the molded product after the molding has a sufficient handling strength. Therefore, when compared with the production method of Patent Document 1, even if the amount of the expensive low softening point binder is reduced, a molded product and a ferro-coke product having the same strength (handling strength, product strength) can be obtained. Moreover, when the addition amount of the low softening point binder and the high softening point binder is equal, a molded product and a ferro-coke product having higher strength (handling strength, product strength) can be obtained.

The iron source material is not particularly limited as long as it can be an iron source of a blast furnace and can be used as a raw material for a molded product, but iron ore is usually used. Further, for example, iron source materials that are by-produced in an ironworks such as blast furnace dust, converter dust, and rolling sludge may be used. Therefore, one or more selected from iron ore and other iron source materials can be used.
A high softening point binder a1 having a softening point of 150 ° C. or higher (hereinafter referred to as “high softening point binder a1” for convenience of explanation) is a pitch-based binder, and examples of the high softening point binder a1 include asphalt pitch (ASP, Softening point: 190 ° C.).

In addition, a low softening point binder a2 having a softening point of less than 100 ° C. (hereinafter referred to as “low softening point binder a2” for convenience of description) is also a pitch-based binder. Examples of the low softening point binder a2 include soft pitch ( SOP, softening point 55 ° C.), propane deasphalted asphalt (PDA, softening point: 65 ° C.), medium pitch (softening point 70 ° C.), and the like, and one or more of these can be used.
In addition, tar a3 (hereinafter referred to as “low-viscosity tar a3” for the sake of convenience of explanation) produced mainly in the process of carbonizing coal is lower in softening point than the low softening point binder a2. As this low-viscosity tar a3, a molded coke production process (coking coal is produced by using a non-caking coal as a main raw material and using a binder to dry coal in the vertical distillation furnace to obtain coke. There are tar generated in the dry distillation step of process), ferro coke tar generated in the dry distillation step when producing ferrocoke, and one or more of these can be used. This low viscosity tar a3 has a softening point lower than that of the low softening point binder a2, has a low viscosity, and is in a liquid phase at room temperature.

Ferro-coke tar is a tar produced in a dry distillation process when producing ferro-coke, and is obtained by cooling the volatile matter of coal. As a method for producing ferro-coke, for example, there is a method in which a molded product of a raw material containing coal, an iron source raw material, and a binder is carbonized in a carbonization furnace as in the present invention, but is not limited thereto. Ferro-coke tar is different from tar normally generated in a coke oven, and has a low low-carbonization temperature, so it has many low molecular weight components and low viscosity. Therefore, the performance as a binder is inferior. Furthermore, since ferro-coke contains iron, ferro-coke tar also contains iron. Tar containing iron is difficult to use in a chemical process that purifies tar to produce pitch and the like. It is also expensive to treat as industrial waste. On the other hand, in the present invention, by utilizing such properties of ferro-coke tar, it can be effectively used as a part of the binder (low-viscosity tar a3).
Moreover, when using ferro-coke tar, it is preferable to use the ferro-coke tar produced when the molded product is subjected to dry distillation in the production method of the present invention (step (C)). There is an advantage that it can be reused in a self-contained manner.

  The softening point of the binder can be measured using, for example, a dropping point / softening point measuring furnace “EP83” manufactured by METTER. In the measurement of the softening point, as shown in FIG. 4, a sample is filled in a platinum sample container 4, heated to increase the temperature at 2 ° C./min, and the sample is softened by this heating. The temperature at which the sample dropped between the LED 5 and the photodiode 6 is measured, and this is used as the softening point.

The method of the present invention includes a step (A) of kneading the raw material containing the above three types of binder components while heating, a step (B) of molding the raw material that has undergone this step (A) into a molded product, and this step. It has the process (C) which carries out dry distillation of the molding obtained by (B), and makes it ferro-coke. Usually, in the step (A), the raw material is kneaded while being heated using a kneader having a raw material heating function (hereinafter, sometimes referred to as “heating and kneading” for convenience of explanation). In the step (B), the raw material is formed using a molding machine, and in the step (C), the molded product is subjected to dry distillation using a dry distillation furnace.
The reason why the raw material is kneaded while heating in the step (A) is to soften and disperse the added binder in the raw material.

In the step (A), the high softening point binder a1, the low softening point binder a2 and the low viscosity tar a3 may be added to the coal and the iron source material at the same time and heated and kneaded. In order to achieve the maximum, it is preferable to add in the embodiment as follows.
(I) When kneading while heating the raw material in step (A), first, coal, iron source raw material and high softening point binder a1 are kneaded, and tar a3 is added to this kneaded raw material and kneaded. Furthermore, a low softening point binder a2 is added to the kneaded material and kneaded.
(Ii) When kneading while heating the raw material in the step (A), first, coal, an iron source raw material and a high softening point binder a1 are kneaded, and the low softening point binder a2 and tar a3 are added to this kneading raw material. Is added and kneaded.

Hereinafter, in the present invention, as the binder to be blended in the raw material, the effects obtained by using the low-viscosity tar a3 together with the high softening point binder a1 and the low softening point binder a2, and the preferred implementations of the above (i) and (ii) A form is demonstrated.
In the present invention, the low softening point binder a2 improves the handling strength of the molded product after molding (as a result, the product strength is also improved), and the high softening point binder a1 is only the handling strength of the molded product after molding. In addition, it improves the product strength of ferro-coke after dry distillation. Thus, it is intended to improve the handling strength of the molded product and the product strength of the ferro-coke by using two types of binders having different softening points and different binder functions.

  Fine pores exist in coal and iron ore (iron source material), which are raw materials for ferro-coke. In particular, inferior quality coal and iron ore have many fine pores, such as steam coal and high crystal water ore. Both the high softening point binder a1 and the low softening point binder a2 are expected to have a binder function of adhering particles to each other by being present on the particle surfaces of coal and iron ore. Since the high softening point binder a1 having a softening point of 150 ° C. or higher has a high melt viscosity, it can be present on the particle surface of coal or iron ore and exhibit a binder function. On the other hand, the low softening point binder a2 having a softening point of less than 100 ° C. has a lower melt viscosity than the high softening point binder a1, and at 100 ° C. or more, the viscosity is low like water, so that coal or iron ore Easy to penetrate into pores, especially inferior coal and iron ore have many fine pores, so many low softening point binders a2 penetrate into the pores and remain on the particle surface. The amount of binder a2 decreases. Since the low softening point binder a2 penetrating into the pores does not contribute to the adhesion strength between the particles, the strength of the obtained molded product is lowered, and as a result, the product strength of ferrocoke is also lowered.

  In the present invention, the low-viscosity tar a3 added as a binder together with the high softening point binder a1 and the low softening point binder a2, has a softening point lower than that of the low softening point binder a2, and is in a liquid state at room temperature. The viscosity is low and the performance as a binder is also inferior. FIG. 2 shows the viscosity at 70 to 140 ° C. of the soft pitch as the low softening point binder a2 and the ferrocoke tar as the low viscosity tar a3. In any temperature range of 70 to 140 ° C., Ferro coke tar has a much lower viscosity than soft pitch. The present invention utilizes the low viscosity of such a low-viscosity tar a3 (particularly ferro-coke tar has an extremely low viscosity), and obtains the following effects. That is, when the low-viscosity tar a3 having a lower viscosity than the low softening point binder a2 is added as in the present invention, the low-viscosity tar a3 having a low viscosity is preferentially (ie, before the low softening point binder a2). As a result, the amount of the low softening point binder a2 penetrating into the fine pores existing in the particles of the coal or iron ore can be suppressed to be small. For this reason, the low softening point binder a2 having high binder performance can be present on the particle surface, and the low softening point binder a2 can function in accordance with the amount added. Fig. 1 schematically shows the principle. Low-viscosity tar a3 with low viscosity penetrates preferentially into the pores of the raw material (coal, iron ore) and enters the pores of the low softening point binder a2. Therefore, the low softening point binder a2 covers the particle surface, and the high binder performance can be sufficiently exhibited. Thereby, both the handling strength of the molded product after molding and the product strength of ferro-coke after dry distillation can be improved.

Next, preferred embodiments (i) and (ii) will be described. In these embodiments, the effect of the present invention can be further enhanced by adding the binder to the raw materials in a specific order and sequentially heating and mixing them.
In the above embodiments (i) and (ii), first, the high softening point binder a1 is added to the coal and iron source raw material, followed by heating and kneading, and then the low softening point binder a2 and low viscosity tar. Add a3 and heat and knead.
A high softening point binder a1 (a binder in a solid state at 150 ° C.) having a softening point of 150 ° C. or higher has a high melt viscosity. The high softening point binder a1 is preferably added from the initial stage of mixing in order to fully blend in with the raw materials, such as coal and iron source materials, and to release some volatile matter. That is, first, it is preferable to add the high softening point binder a1 to the coal and iron source material and perform heating and kneading. This high softening point binder a1 improves not only the handling strength of the molded product after molding, but also the product strength of ferro-coke after dry distillation. The reason why the volatile matter is released is to suppress the occurrence of defects such as blistering and cracking in the molded product due to the influence of the volatile matter during dry distillation.

  On the other hand, the low softening point binder a2 having a softening point of 100 ° C. or lower is used for improving the handling strength of the molded product after molding (and consequently improving the product strength). Since the low softening point binder a2 has a low melt viscosity and a large amount of volatile components, when it is added from the beginning of mixing, most of it is volatilized, and the effectiveness as a binder may not be sufficiently exhibited. Furthermore, it is preferable to add the low softening point binder a2 in a sufficiently dry state in order to sufficiently bring out the dispersibility and wettability of the binder a2 in the raw material. Therefore, the low softening point binder a2 is preferably added at a later stage, and particularly preferably immediately before discharging the kneading raw material from the kneader. Specifically, it is preferable to add the low softening point binder a2 when the temperature of the raw material to be heated and kneaded reaches about [the raw material discharge temperature−20 ° C.]. For example, when the raw material discharge temperature is 160 ° C, the low softening point binder a2 is added when the raw material discharge temperature is 220 ° C, and when the raw material discharge temperature is 220 ° C, the low softening point binder a2 is added. Here, the raw material discharge temperature is the temperature at which the raw material is discharged from the kneader (the highest temperature in the heating / kneading step). In the actual operation, this raw material discharge temperature is set as a target temperature.

  As described above, in the present invention, the low-viscosity tar a3 having a lower viscosity than the low-softening point binder a2 is added, and the low-viscosity tar a3 having a low viscosity is preferentially (that is, the low softening point binder). Prior to a2, it penetrates into the fine pores present in the particles of coal and iron ore, so that the penetration of the low softening point binder a2 into the pores is suppressed. In the embodiment of i), first, after heating and kneading the coal, the iron source material and the high softening point binder a1, the low-viscosity tar a3 is added to the kneaded material and heated and kneaded. A low softening point binder a2 is added to the kneaded raw material and heated and kneaded. In the above embodiment (ii), first, the coal, the iron source material and the high softening point binder a1 are heated and kneaded, and the low softening point binder a2 and the low viscosity tar a3 are added to the kneaded material. Heat and knead.

  Here, in order to permeate the low-viscosity tar a3 preferentially (that is, before the low softening point binder a2) into the fine pores existing in the particles of coal or iron ore, the implementation of the above (i) Although the form is more advantageous, even in the embodiment (ii) above, the low-viscosity tar a3 and the low softening point binder a2 have different viscosities, so that preferable effects can be obtained. Note that the low-viscosity tar a3 and the low softening point are not included in the embodiments (i) and (ii) described above, even when the low softening point binder a2 and the low-viscosity tar a3 are added together with the high softening point binder a1 from the beginning of mixing. Since the binder a2 has a difference in viscosity, a certain effect can be obtained.

  In the above embodiment (i), first, the coal, the iron source material and the high softening point binder a1 are heated and kneaded, and the material temperature is low in the range of 100 ° C. or more and less than 130 ° C. Viscous tar a3 is added and heated and kneaded. Furthermore, the raw material temperature for this kneaded raw material is 130 ° C. or higher, and ranges from [raw material discharge temperature −30 ° C.] to [raw material discharge temperature −10 ° C.] (for example, It is preferable to add the low softening point binder a2 in the range of 130 to 150 ° C. and heat and knead. In the actual operation, this raw material discharge temperature is set as a target temperature. If the raw material temperature when adding the low-viscosity tar a3 is less than 100 ° C., the viscosity may be high and dispersibility in the kneaded raw material may be insufficient. Moreover, the raw material temperature when adding the low softening point binder a2 is 130 ° C. or higher and the range of [raw material discharge temperature−30 ° C.] to [raw material discharge temperature−10 ° C.] This is because the low softening point binder a2 is effectively dispersed on the outer surfaces of the coal particles and iron ore particles in which the low-viscosity tar a3 has permeated.

  In the above embodiment (ii), first, coal, an iron source raw material and a high softening point binder a1 are heated and kneaded, and the raw material temperature is 120 ° C. or higher with respect to this kneaded raw material and [raw material discharge temperature − It is preferable to add the low softening point binder a2 and the low-viscosity tar a3 in the range of 30 ° C. to [raw material discharge temperature−10 ° C.] (for example, in the range of 120 to 150 ° C.), and heat and knead. In the actual operation, this raw material discharge temperature is set as a target temperature. The raw material temperature when adding the low softening point binder a2 and the low-viscosity tar a3 is 120 ° C. or higher and the range of [raw material discharge temperature−30 ° C.] to [raw material discharge temperature−10 ° C.] This is because the temperature dependence of the viscosity of the binder a2 and the low-viscosity tar a3 is used. That is, the viscosity of both the low softening point binder a2 and the low viscosity tar a3 increases due to a decrease in temperature, but the temperature dependence of the viscosity of the low softening point binder a2 is large, and the lower the temperature becomes, the lower the softening point binder a2 and the lower the viscosity. The viscosity difference of tar a3 widens. This difference in viscosity is the driving force for preferential penetration of the low-viscosity tar a3 into coal particles and iron ore particles. However, when the temperature is too low, the viscosity of the low softening point binder a2 is increased, and the uniform dispersibility in the kneading raw material may be impaired.

In any of the above embodiments (i) and (ii), the handling strength and dry distillation of the molded product after molding can be obtained by adding two types of binders having different viscosities in the temperature range where the moisture of the raw material is dried. The product strength of the later ferrocoke can be particularly improved.
In the step (A) of the present invention, the raw material temperature when discharging the raw material from the kneader is not particularly limited, but it is possible to ensure the dispersibility of the binder and to suppress the decrease in the binder effect due to the volatilization of the binder component. From the standpoint of preventing deterioration, it is preferable to discharge the heated and kneaded raw material from the kneader at a raw material temperature of 150 to 170 ° C., and mold this raw material in step (B) to obtain a molded product. If the raw material temperature when discharging from the kneading machine is less than 150 ° C, the dispersibility of the binder may be non-uniform. On the other hand, if it exceeds 170 ° C, the binder effect itself may be reduced and coal may be modified. There is.

  The mixing ratio of coal and iron source material may be appropriately selected according to the amount of coke and iron source required as blast furnace raw materials. For example, coal 60 to 90 mass%, iron source material 10 to 40 mass It is blended at a ratio of about%. Further, the amount of the binder is not particularly limited, but, for example, in the ratio of the kneading raw material, the high softening point binder is 0.5 to 2.0 mass%, and the low softening point binder a2 is 1.0 to 4.0 mass. %, Low-viscosity tar is blended at a ratio of about 1.0 to 5.0% by mass.

Hereinafter, the method of the present invention will be described using the embodiment shown in FIG. 3 as an example.
FIG. 3 schematically shows an embodiment of the present invention using a ferro-coke production facility and this production facility, wherein 1 is a kneading machine, 2 is a molding machine, and 3 is a dry distillation furnace. This embodiment shows an example in the case of using iron ore as an iron source material.
Coal and iron ore to be used are both granular, for example, coal has a particle size of 3 mm or less and iron ore has a particle size of 0.5 mm or less. In order to obtain this particle size, coal and iron ore are pulverized by a pulverizer as necessary.
The blending ratio of coal and iron ore is appropriately selected according to the amount of coke and the amount of iron source required as a blast furnace raw material, as described above. For example, coal 60 to 90% by mass, iron ore 10 to 40 It mix | blends in the ratio of the mass%.

FIG. 5 shows an embodiment of the kneading machine 1. The kneading machine 1 includes a main body 8 into which raw materials are charged, and stirring means 9 (stirring blades) for mixing the raw materials provided inside the main body 8. ) And heating means 10 attached to the main body 8. The heating means 10 is composed of a jacket or the like through which high-temperature oil or high-pressure steam flows, and the raw material charged in the main body 8 can be heated to a temperature range of about 120 ° C to 240 ° C.
The upper part of the main body 8 is opened, and the raw material is charged from this upper part. A raw material discharge unit 11 is provided at the lower part of the main body 8, and the raw material kneaded by the stirring means 9 is discharged from the raw material discharge unit 11.
In addition to the stirring blade method as in the present embodiment, various types such as a screw type can be used as the kneading machine 1, but considering the dispersibility of coal and iron source materials, the screw type A kneader kneaded with a stirring blade rotating at a higher speed than a kneader such as the above is desirable.

  In step (A), the kneader 1 is charged with the coal and iron ore blended as described above, and the binder, the high softening point binder a1, the low softening point binder a2, and the low viscosity tar a3. These raw materials are kneaded while being heated. In the preferred embodiment, first, coal and iron ore and the high softening point binder a1 are charged into the kneader 1 and kneaded while being heated. In the embodiment (i), the low-viscosity tar a3 Then, heating and kneading are continued, and then a low softening point binder a2 is further charged, followed by heating and kneading. In the embodiment (ii), the low-viscosity tar a3 and the low softening point binder a2 are charged, followed by heating and kneading.

  In the step (B), the raw material heated and kneaded in the kneading machine 1 in the step (A) is molded by the molding machine 2 to obtain a massive molded product. The molding machine 2 can be of any type. The raw material heated and kneaded by the kneader 1 is quickly molded by the molding machine 2, and thus is molded at a temperature close to the temperature heated by the kneader 1. The present invention is not a method of forming a raw material by using the caking property of coal softened and melted hot, but the material is molded and held with an added binder. Therefore, it is advantageous to mold the raw material that maintains the temperature heated by the kneader 1.

FIG.6 and FIG.7 shows one Embodiment of the molding machine 2, This molding machine 2 is a double roll molding machine. FIG. 6 is an overall explanatory view of the molding machine, FIG. 7 shows a pair of molding rolls, FIG. 7 (a) is a perspective explanatory view, and FIG. 7 (a) is a molding applied to a contact point of the pair of molding rolls. It is explanatory drawing which shows a pressure.
This double roll molding machine has a pair of molding rolls 13 that rotate in opposite directions, and pressure-molds the mixed raw material at the contact point of the pair of molding rolls 13. A recess 13a (mold) is formed on the outer peripheral surface of the molding roll 13, and a lump-shaped molded product matching the shape of the recess 13a is molded. The mixed raw material is supplied to the contact portion of the pair of forming rolls 13 by the screw feeder 15. The molded product is stored in the receiving box 16.

As shown in FIG. 7, in the double roll molding machine, molding pressure is applied to the contact point of the pair of molding rolls 13. The molding pressure is expressed by linear pressure (ton / cm) = pressurizing force (ton) / roll width (cm). The linear pressure of the double roll molding machine is preferably 2 to 8 ton / cm, particularly 4 to 6 ton / cm. When the molding pressure is less than 2 tons / cm, the density of the molded product is reduced, and neither the handling strength nor the product strength after dry distillation can be expected. When the molding pressure is greater than 8 tons / cm, the density of the molded product increases, but rebound cracking increases and the molding yield decreases. The size of the molded product is not particularly limited, but is usually about ³ to 95 cm ³ , preferably about 6 to 60 cm ³ . The molding size varies depending on the application in the blast furnace.

  In the step (C), the molded product obtained in the step (B) is subjected to dry distillation in the dry distillation furnace 3 to produce ferro-coke. As the dry distillation furnace 3, a vertical shaft furnace type vertical dry distillation furnace having chamotte bricks may be used, or a room furnace type dry distillation furnace similar to the chamber furnace type coke oven may be used. The dry distillation of the molded product is performed at 800 ° C. to 950 ° C., for example. The high softening point binder softens and melts during dry distillation, and the high softening point binder exhibits a binder effect in the ferro-coke after dry distillation.

  In the ferro-coke manufacturing method, in order to investigate the influence of molding conditions on the handling strength of molded products and the product strength of ferro-coke after dry distillation, ferro-cokes were experimentally manufactured and the quality evaluation of the molded products and products was performed. .

[Example 1]
Ferro-coke was produced by the following method. First, the raw material for ferro-coke was adjusted. Coal used is a jaw crusher with a particle size adjusted to 2 mm or less (-2 mm), and iron ore crushed to a particle size of 0.5 mm or less (-0.5 mm) with a roll mill at a predetermined ratio. Blended. In the example of the present invention, coal and iron ore are charged into a kneader, and 2% by mass of alfalt pitch (high softening point binder a1) is added in a ratio of all the mixed raw materials, followed by heating and kneading. When the temperature reached 140 ° C., ferro-coke tar (low viscosity tar a3) and soft pitch (SOP, low softening point binder a2) were simultaneously added in predetermined amounts. Further, heating and kneading were continued, and the raw material was discharged at a raw material temperature of 160 ° C. The discharged raw material was immediately molded into a 6 cm ³ molded product by a double roll molding machine. Ferro-coke was produced by dry distillation of this molded product in a vertical carbonization furnace under the condition of staying at 850 ° C. for 2 hours or more. Moreover, in the conventional example and the comparative example, all the binders were added from the beginning, and ferrocoke was manufactured under the same conditions as the inventive examples except for the above.

The quality evaluation of the molded product in the manufacturing process and the manufactured ferro-coke was performed using a type I testing machine. The molded product was evaluated for strength using a 30-rotation 6 mm index (ID30 / 6), and ferro-coke was evaluated for strength using a 160-rotation 6 mm index (ID160 / 6). The target strength of the molded product was set to 88, and the target strength of ferro-coke was set to 82, respectively. Further, in order to evaluate the molding yield of the molded product, the molded product was sieved with a 15 mm sieve, and the mass ratio of the molded product retaining the original shape on the sieve was examined.
Table 1 shows the composition of raw materials, molding conditions, and quality evaluation results of molded products and ferro-coke products.

  In Table 1, No. 1 (conventional example) is an example in which asphalt pitch and soft pitch are used in the conventional addition method. Molded product strength and product strength (ferrocoke strength) satisfy target values. No. 2 (conventional example) is an example in which the addition amount of the soft pitch is increased by 1 mass% with respect to No. 1, and the yield and strength are improved compared to No. 1. The comparative examples of No. 3 and No. 4 are examples in which ferro-coke tar is added instead of soft pitch, and the strength is lower than the conventional example in which the same amount of soft pitch is added. Is inferior to soft pitch.

In contrast to the No. 2 soft pitch of 4 mass%, the No. 5 invention example has a soft pitch of 3 mass%, a ferrocoke tar of 1 mass%, and a total of 4 mass%, but the yield and strength are almost the same as No.2. It has been. The invention No. 6 is an example in which the soft pitch is further reduced by 1 mass% and the ferro-coke tar is increased by 1 mass%, but both the yield and strength exceed the target values. The invention example of No. 7 is an example in which the soft pitch is reduced by 0.5 mass% from No. 6, but a value equivalent to No. 1 of 3 mass% soft pitch is obtained.
As described above, ferro-coke tar having a low viscosity is used as a binder, and this ferro-coke tar is added to the raw material before the soft pitch, so that the ferro-coke tar penetrates into the pores of the raw material and then softens. It can be seen that as a result of the pitch being coated on the particle surface, the binder effect by the soft pitch is appropriately obtained, and the strength of the molded product and the product strength are improved.

[Example 2]
Ferro-coke was produced by the following method. Coal and iron ore used the same thing as Example 1, and these were mix | blended in the predetermined ratio. In the example of the present invention, coal and iron ore are charged into a kneader, and 2% by mass of alfalt pitch (high softening point binder a1) is added in a ratio of all the mixed raw materials, followed by heating and kneading. When the temperature reached 120 ° C., a predetermined amount of ferrocoke tar (low viscosity tar a3) was added. Further, heating and kneading were continued, and when the raw material temperature reached 140 ° C., a predetermined amount of soft pitch (SOP, low softening point binder a2) was added, and further heating and kneading were continued, and the raw material was discharged at a raw material temperature of 160 ° C. The discharged raw material was immediately molded into a 6 cm ³ molded product by a double roll molding machine. Ferro-coke was produced by dry distillation of this molded product in a vertical carbonization furnace under the condition of staying at 850 ° C. for 2 hours or more.

The quality evaluation of the molded product during the production process and the produced ferrocoke was performed in the same manner as in Example 1. Table 2 shows the composition of raw materials, molding conditions, and quality evaluation results of molded products and ferro-coke products.
The invention example of No. 8 has a soft pitch of 3 mass%, a ferro-coke tar of 1 mass%, and a total of 4 mass%, but the yield and strength are almost the same as those of No. 2 of Example 1. The invention No. 9 is an example in which the soft pitch is further reduced by 1 mass% and the ferro-coke tar is increased by 1 mass%, but both the yield and strength exceed the target values. The invention example of No. 10 is an example in which the soft pitch is reduced by 0.5 mass% from No. 9, but a value equivalent to No. 1 of Example 1 with a soft pitch of 3 mass% is obtained.
As described above, using ferro-coke tar having a low viscosity as a binder and adding it to the raw material together with the soft pitch, the ferro-coke tar having a lower viscosity than the soft pitch preferentially penetrates into the pores of the raw material, and then As a result of the soft pitch being coated on the particle surface, it can be seen that the binder effect by the soft pitch is appropriately obtained, and the strength of the molded product and the strength of the product are improved.

DESCRIPTION OF SYMBOLS 1 Kneading machine 2 Molding machine 3 Dry distillation furnace 8 Main body 9 Agitation means 10 Heating means 11 Raw material discharge part 13 Forming roll 15 Screw feeder

Claims (9)

In a method for producing ferro-coke by molding a raw material containing coal, an iron source raw material and a binder, and subjecting the molded product to dry distillation,
As a binder, a high softening point binder (a1) having a softening point of 150 ° C. or higher, a low softening point binder (a2) having a softening point of less than 100 ° C., and a softening point binder having a low softening point produced in the process of dry distillation of coal. A step (A) of kneading while heating a raw material containing tar (a3) lower than (a2), a step (B) of forming the raw material after the step (A) into a molded product, A method for producing ferro-coke, comprising a step (C) of subjecting the molded product obtained in B) to dry distillation to obtain ferro-coke.   When kneading while heating the raw material in step (A), first, coal, iron source raw material and high softening point binder (a1) are kneaded, and tar (a3) is added to this kneaded raw material and kneaded. Furthermore, the low-softening point binder (a2) is added and kneaded to the kneaded raw material, and the method for producing ferro-coke according to claim 1.   When kneading while heating the raw material in the step (A), first, the coal, the iron source raw material and the high softening point binder (a1) are kneaded, and the raw material temperature is 100 ° C. or higher and lower than 130 ° C. In addition, tar (a3) is added and kneaded in the range of, and the raw material temperature is 130 ° C. or higher and the raw material discharge temperature is −30 ° C. to the raw material discharge temperature −10 ° C. The method for producing ferro-coke according to claim 2, wherein the low softening point binder (a2) is added and kneaded.   When kneading while heating the raw material in step (A), first, coal, an iron source raw material and a high softening point binder (a1) are kneaded, and the low softening point binder (a2) and tar are mixed with this kneading raw material. The method for producing ferrocoke according to claim 1, wherein (a3) is added and kneaded.   When kneading while heating the raw material in the step (A), first, the coal, the iron source raw material and the high softening point binder (a1) are kneaded, and the raw material temperature is 120 ° C. or higher and [ The ferro-coke according to claim 4, wherein the low softening point binder (a2) and tar (a3) are added and kneaded in the range of the raw material discharge temperature -30 ° C to the raw material discharge temperature -10 ° C. Manufacturing method.   The method for producing ferro-coke according to any one of claims 1 to 5, wherein the tar (a3) is a ferro-coke tar produced in a dry distillation step when producing ferro-coke.   The method for producing ferro-coke according to claim 6, wherein the ferro-coke tar is produced in step (C).   The raw material kneaded while being heated in the step (A) is discharged from the kneader at a raw material temperature of 150 to 170 ° C, and the raw material is molded in the step (B) to form a molded product. 8. A method for producing ferro-coke according to any one of 7 above.   The method for producing ferro-coke according to any one of claims 1 to 8, wherein in the step (C), the molded product is subjected to carbonization in a vertical carbonization furnace.

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