JP2008189994A - Method for producing granulated and sintered raw materials - Google Patents

Abstract

An object of the present invention is to propose a production technique that can suppress the amount of binder used and is advantageous for obtaining a dry granulated sintered raw material with less powdering.
To produce a granulated sintered raw material by adding a binder and water to a sintered raw material, and granulating the dried raw material, at least a part of the binder is preliminarily mixed with the sintered raw material, A method for producing a granulated and sintered raw material in which granulation is performed by adding water.
[Selection] Figure 1

Description

  The present invention relates to a method for producing a granulated and sintered raw material, and in particular, proposes a method for producing a low-moisture dry granulated and sintered raw material used when producing sintered ore for a blast furnace.

  The sintered ore used as a main raw material in the blast furnace ironmaking method is generally manufactured through a process as shown in FIG. Hereinafter, the manufacturing method will be briefly described according to the illustrated flow. As shown in FIG. 1, iron ore powder having an average particle size of about 1.0 to 5.0 mm, iron mill recovered powder, sintered ore sieving powder, limestone and dolomite-containing CaO raw materials (hereinafter referred to as CaO-based auxiliary materials) ), A sintering raw material composed of a granulating aid such as quicklime and a coagulant such as coke powder or anthracite is first stored in the hopper 1. Then, from these hoppers 1, various raw materials are cut out at a predetermined ratio on a conveyor, mixed with a mixing drum mixer 2a, etc., added with an appropriate amount of water to adjust the humidity, and then introduced into the granulating drum mixer 2b. And granulated to obtain raw granulated particles (pseudo particles) having an average diameter of 3.0 to 6.0 mm. Next, the granulated particles (pseudo particles) of the granulated sintered raw material are transferred from the surge hoppers 4 and 5 arranged on the sintering machine through the drum feeder 6 and the cutting chute 7 to endless moving type sintering. A charging layer 9 is formed on the binding pallet 8 so as to have a thickness (height) of about 400 to 600 mm, and then the ignition furnace 10 installed above the charging layer 9 is used. The charcoal material in the charging layer is ignited. Then, the carbon material (interior carbon material) in the granulated particles in the charging layer 9 is sequentially burned by suction by the wind box 11 disposed under the pallet 8, and the generated heat is generated by the combustion heat generated at this time. Sintering is performed by burning and melting the grain-sintered raw material. Thereafter, the sintered layer (sintered cake) generated on the pallet is crushed and sized, and 5.0 mm or more is recovered as a product sintered ore.

In the above-described method for producing sintered ore, when the ignition material 10 ignites the carbon material on the surface of the charging layer 9 (raw material deposition layer), suction is performed from the top of the charging layer 9 toward the lower layer. Due to the action of the suction gas, the carbonaceous material blended in the charging layer 9 is combusted, and this combustion zone gradually advances to the lower layer and forward as the pallet 8 moves. At this time, the water in the charged raw material particles evaporates due to the heat generated by the combustion of the carbonaceous material, but is sucked downward and concentrated in the raw material of the lower wet zone where the temperature has not risen yet. When the concentration becomes higher than a certain level, moisture is filled in the voids of the raw material particles, which are the suction gas flow paths, and the ventilation resistance increases. Note that the melt resistance necessary for the sintering reaction also increases the airflow resistance. It is known that the ventilation resistance of this wet zone accounts for about half or more of the total ventilation resistance of the charging layer 9, and in order to improve productivity, at least reduce the ventilation resistance due to moisture condensation in this wet zone. Is considered effective. For example, Patent Document 1 proposes a method of drying sintered raw material particles by sending hot air during the granulation process of the sintered raw material.
Japanese Patent Laid-Open No. 03-215629

  However, in the above-described conventional technology, collapse of the raw granulated particles inevitably occurs due to a decrease in moisture in the raw granulated particles in the drying step and rolling of the raw granulated particles. As a result, when the obtained granulated and sintered raw material is charged and deposited on the pallet of the sintering machine and sintered, the fine powder generated by the collapse fills the gaps between the raw material particles that are suction gas flow paths. As a result, the ventilation resistance is increased. As a result, the suction gas drifts and burn unevenness occurs, leading to a decrease in sinter yield and productivity. In this regard, if the amount of the binder used is increased, the bonding between the raw material particles becomes stronger, but there is a problem that the binder cost and thus the product cost is increased.

  An object of the present invention is to propose a production technique that can suppress the amount of binder used and is advantageous for obtaining a dry granulated sintered raw material with less powdering.

  As a result of studying a method for realizing the object of the present invention, the inventors have obtained knowledge that it is effective to devise a method for adding a binder. Invented the invention. That is, the inventors previously dissolved at least a part of this binder (powder) with the sintering raw material in advance, rather than dissolving the binder in water or adding it to the sintering raw material in a suspended state. Mixing, and then granulating by adding water during granulation, the granulated particles composed of pseudo particles are large and firm, and the granulated particles after drying the granulated particles, That is, it has been found that the particle diameter of the granulated and sintered raw material is also large and strong.

  This is because when the binder and water are mixed and dissolved or suspended in advance, the viscosity of the mixed liquid increases or the liquid gels, which is the sintering raw material and liquid (binder + water). This is thought to be due to the fact that the mixture tends to collapse during drying and subsequent handling after granulation. On the other hand, if most of the binder is mixed with the sintering raw material in advance and then water is added for the first time during granulation, the binder will be uniformly dispersed in the sintering raw material. It is thought that the granulation characteristics are improved.

  That is, in the present invention, a binder and water are added to a sintered raw material, granulated, and dried to produce a granulated sintered raw material. At least a part of the binder is premixed with the sintered raw material, Then, the manufacturing method of the granulation sintering raw material characterized by adding water and performing the granulation process is proposed.

In the present invention,
a. The binder is used in a state where 50 mass% or more of the binder is premixed with the combustion raw material, and the remaining binder is preliminarily dissolved in water or suspended without being dissolved in water.
b. The binder includes an organic binder that has a function as a binder even after the granulated water evaporates in a powder form,
c. The organic binder is a gum-based material or a cell-based thickener;
d. The gum substance is guar gum or gum arabic;
e. The cell thickener is carboxymethylcellulose;
f. The binder comprises an organic binder and an inorganic binder;
g. The inorganic binder is at least one selected from the group consisting of bentonite and water glass;
h. The water to be added at the time of granulation is granulated by adding an excessive amount than the appropriate moisture value required according to the sintering raw material,
i. The drying uses a rotary kiln,
j. The drying consists of pre-drying the raw granulated particles of the sintered raw material and then performing the main drying;
k. For the drying, preliminary drying is performed using a heating medium at 80 ° C., and main drying is performed using a heating medium at 200 ° C. or higher.
l. Adjusting the moisture after drying to 4.0 mass% or less,
It can be considered as a more preferable solution.

  According to the present invention, a strong granulated and sintered raw material can be produced with a small amount of binder. Moreover, since the granulated and sintered raw material is less pulverized, the size (particle size) of the raw granulated particles can be maintained as it is after drying, reducing the ventilation resistance of the entire charged layer on the sintering machine pallet. realizable. As a result, it is possible to produce a high-strength product sintered ore with high productivity, and it is possible to reduce the cost of producing the sintered ore by reducing the amount of binder used.

  In the operation of the sintering machine, as described above, the air permeability in the charging layer of the sintering raw material on the sintering machine pallet (here, the “granulated sintering raw material” after drying) It is an important factor that affects yield and productivity, and of course, maintaining the granulated particle diameter of the sintered raw material is an essential condition for ensuring the air permeability. Therefore, the present invention develops a new method of adding a binder at an appropriate timing in order to strengthen the granulated particles and prevent pulverization, and in the subsequent drying step, raw granulation is performed. The technique which can suppress that a particle collapse | disintegrates is proposed. The details will be described below.

  FIG. 2 shows an example of a general granulated and sintered raw material manufacturing process, which is characterized in that a binder is simultaneously added together with water for granulation to the drum mixer 2b. And in this method, the water | moisture content in a raw granulated particle is adjusted with the rotary kiln 3 at the next process, and it is about 4 mass% or less.

  On the other hand, FIG. 3 shows an example of the manufacturing process of the granulated and sintered raw material according to the present invention, which is characterized in that at least a part of the binder is preliminarily preliminarily mixed with the sintered raw material by the drum mixer 2a. Then, the mixture is charged into another drum mixer 2b and granulated while supplying only water, or the remainder of the binder is added together with water, or the binder is suspended in water in advance. This is a method of granulating by supplying the material into the drum mixer 2b. In this method, the raw granulated particles thus obtained are then charged into the rotary kiln 3 and dried while rolling, and the moisture in the granulated particles is adjusted to 4 mass% or less, and the dried granulated particles are dried. A raw material for grain sintering.

(1) Study on granulated particles that can withstand external force in the drying step The inventors first examined a granulating binder in order to solve the above problems during drying. As a result, in the present invention, as the binder used at the time of granulation, it is possible to maintain the high strength of the granulated particles that have been pseudo-particled even after drying. It was decided to use an organic binder exhibiting the above-mentioned operational effects, or to use a mixture of this organic binder and various binders conventionally used. This is because with such a binder, strong raw granulated particles can be produced, and even after moisture has been removed by drying, the collapse of the dried granulated particles can be reliably prevented. As a result, particles that maintain the average particle size at the time of granulation after drying can be charged on the pallet of the sintering machine, and the sintered bed charging layer is formed by the wet zone that is generated during firing and sintering. The problem of deterioration of air permeability can be solved.

  In selecting the binder to be used in the present invention, the inventors paid attention to the tensile strength of the granulated particles after drying, that is, the granulated sintered raw material. Specifically, the tensile strength of the granulated particles is expressed by the following formula (1): the suction pressure due to the capillary force due to the surface tension of the cross-linking substance such as a binder and the external force due to the viscosity of the cross-linking substance. It is expressed as the sum of the resistance against The resistance against external forces (the resistance against powdering of the powder) greatly depends on the viscosity μ of the cross-linking substance, that is, the binder, and when the binder viscosity μ increases, the tensile strength of the granulated particles as the granulated body increases. And is known to be less prone to collapse.

ここで、σ：造粒体の引張強度、γ：架橋物質の表面張力、θ：粉体との接触角、μ：架橋物質の粘度、Ｓ：粉体表面積、Ψ：液充満度（＝０．６）、ε：造粒物の空隙率、Ｄ：比表面積相当径、a：架橋液体の曲率半径、である。

Here, σ: Tensile strength of the granulated body, γ: Surface tension of the cross-linked substance, θ: Contact angle with the powder, μ: Viscosity of the cross-linked substance, S: Powder surface area, Ψ: Degree of liquid fullness (= 0 6), ε: porosity of the granulated product, D: specific surface area equivalent diameter, a: radius of curvature of the crosslinking liquid.

  Therefore, the inventors have focused attention on the relationship between the viscosity of the binder during granulation and the strength of the granulated particles, and as a result of repeated studies, the use of organic binders in time (addition mixing) results in strong granulated particles. In this case, even after the moisture is removed by drying, the granulated particles can be reliably prevented from collapsing. As a result, it was found that the particle size during granulation can be maintained even after drying.

  That is, the organic binder is not a method in which water and the organic binder are added to the mixed sintered raw material at once by the drum mixer 2b as in the past, but at least a part (≧ 50 mass%) of the organic binder is previously added. When added to the mixed sintered raw material, the organic binder-containing mixed sintered raw material is charged into the drum mixer 2b, granulated by a method of adding only water or water and the remaining organic binder therein, and then dried. It was found that desirable granulated particles can be obtained.

  Among the binders used in the present invention, particularly desirable organic binders are preferably neutral polysaccharide gum-based materials and cellulose-based thickeners, and the gum-based materials include guar gum and gum arabic. it can. Further, the organic binder may be used alone or in combination with several kinds of binders. In addition to the use of the above-mentioned gum-based material and cellulose-based thickener, the dispersion of the thickener As the reinforcing agent, a substance having a carboxylic acid group can be used in combination, or in combination with an inorganic binder made of bentonite or water glass, which will be described later.

  FIG. 4 shows changes in the cumulative ratio of particle diameter before and after drying by a rotary kiln in sintered raw materials (granulated particles) granulated using different binders. (A) is the example which added quick lime together with water and a binder to the sintering raw material at the time of granulation. The granulated particle size distribution, which was coarse on the rotary kiln entry side, collapses due to drying and rolling in the rotary kiln, and the fine grain portion is greatly increased on the rotary kiln exit side.

  Moreover, (b) of FIG. 4 is an example at the time of using gum arabic which is a gum-type substance as an organic binder instead of the quicklime of said (a) as a binder, (d) of FIG. Shows an example when CMC (carboxymethylcellulose), which is a cellulose-based thickener, is used instead of quicklime. In any case, there is almost no change in the rotary kiln entrance and exit sides and the particle size cumulative ratio. That is, it can be seen that drying proceeds without causing collapse even by drying and rolling in the rotary kiln.

  The addition effect of gum arabic, which is a gum-based material, occurs at an addition amount of 0.01 mass% or more, and the upper limit is about 1.0 mass% although it is determined from the addition cost. The reason is that if it is less than 0.01 mass%, the granulated particles are observed to be disintegrated after the drying step, while the effect of the addition is almost saturated at about 1.0 mass%. A preferred range is 0.05 to 0.5 mass%, more preferably 0.1 to 0.3 mass%.

  On the other hand, the effect of addition of CMC (carboxymethylcellulose), which is a cellulose-based thickener, is the addition amount of about 0.01 mass% or more like the gum arabic, and the upper limit is determined from the addition cost. About 0.0 mass%. The reason is that if it is less than 0.01 mass%, the granulated particles are observed to be disintegrated after the drying step, and the effect of the addition is almost saturated at 1.0 mass%. A preferred range is 0.05 to 0.5 mass%, more preferably 0.1 to 0.3 mass%.

  Moreover, FIG.4 (c) is an example which replaced with the gum arabic of said (b), and used the guar gum which is the same neutral polysaccharide as an organic binder. As shown in this figure, in this example, the granulated particles that were coarse on the rotary kiln entry side collapse due to drying and rolling in the rotary kiln, and the fine grain part increases on the exit side. By adding and mixing guar gum, and then granulating with the addition of granulated water, changes similar to those of gum arabic shown in (b) are exhibited. Thus, it was found that guar gum can also be used.

  The effect of adding this guar gum is the same as that of gum arabic. The addition amount is about 0.01 mass% or more, and the upper limit is about 1.0 mass%, although it is determined from the addition cost. The reason is that if it is less than 0.01 mass%, the granulated particles are observed to be disintegrated after the drying step, and the effect of the addition is almost saturated at 1.0 mass%. A preferred range is 0.05 to 0.5 mass%, more preferably 0.1 to 0.3 mass%. Thus, a gum type substance and a cellulose type thickener can be used suitably as an organic binder.

  In the present invention, when using an organic binder such as gum arabic, guar gum, CMC, etc., as described above, it is preferable to mix at least part of the powder with the sintering raw material in advance before adding water. The reason for this is that if these binders are dissolved in water and then mixed with the sintering raw material, the uniform dispersion of the binder between the particles is inhibited, resulting in a decrease in the strength of the granulated particles. Since the granulation is performed in a state where the organic binder adheres to the granules in a coated state, the amount of addition increases. Therefore, by adding the organic binder in the powder state before adding the granulated water to the sintering raw material, mixing and granulating, and then adding the granulated water and granulating It is preferable to develop the strength of the granulated particles with a small binder addition amount.

  FIG. 5 and FIG. 6 show the influence of the existing state of the binder on the granulation strength. When using an organic binder such as gum arabic, guar gum, CMC, etc. It is a figure explaining the principle which can raise intensity | strength. That is, FIG. 5 schematically shows the distribution state of the binder in the powder packed bed, and (a) shows a case where there is no wettability obtained by adding the binder separately from water. (B) is a wet state (suspended state) added by suspending the binder in water, and (c) is a coating state in which the binder and water are added simultaneously (the binder was previously dissolved in water). An example of (generated by state) is shown.

Next, since the inventors examined a method of adding a binder (organic) for reducing the amount of addition in order to produce a granulated sintered raw material at a low cost, an explanation will be given with reference to FIG.
FIG. 6 (a) shows that an organic binder is previously added and mixed in a powdered state into the sintered raw material (state (1)), and then charged in another drum mixer to add granulated water, or powder. The state at the time of adding an organic binder with granulated water is shown. In this case, a large number of voids exist in the ore (including return ore) of the sintering raw material, and the binder penetrates into the voids (porous) (state (2)). It was ascertained that the amount of binder on the ore surface that contributes to the grain strength decreases (state (3)).

  In addition, in this invention, use of an inorganic binder is not prevented. When the inorganic binder is selected from the group consisting of bentonite and water glass, the combined use with an organic binder is effective. Inorganic binder selected from bentonite and water glass acts as a thickener when using organic binders, and exhibits the effect of reducing the amount of organic binder added. Combined use does not reduce the effect of the binder. .

  FIG. 7 is a diagram for explaining operational effects when CMC is used as an organic binder and bentonite is used as an inorganic binder. Bentonite added together with the granulated water closes the gaps between the sintered raw material ores, so that the effect of reducing the amount of CMC added is exhibited. The same applies when used in combination with other organic binders.

  Examples of organic binders that can be used in addition to the examples described above include organic binders such as welan gum or organic binders having a carboxylic acid group. The selection of the inorganic binder and / or the organic binder may be appropriately determined in consideration of compatibility with the sintering raw material.

In addition, when using an organic binder, it is preferable to avoid using quicklime as a binder. When used together with quicklime, the carboxylic acid group of the gum-based material and cellulose thickener reacts with Ca ²⁺ ions contained in quicklime, reducing the binder action, lowering the granulation property, and worsening air permeability. Because it invites.

  Moreover, when using an organic binder, in order to reduce the amount of organic binder and aim at cost reduction, it is preferable to reduce or suppress the usage amount of a return ore as a sintering raw material. Returning ore that is porous absorbs the added binder into the pores and reduces its effectiveness. For this reason, the use of a large amount of return ore requires an increase in the amount of binder used, and when the binder is insufficient due to absorption, the granulated particles are disintegrated during drying.

(2) Examination of treatment in drying process The temperature of the heating medium used in the present invention for cleaning does not cause the granulated particles to collapse or explode when the granulated particles are heated and heated. It is necessary to make it. Therefore, the present invention proposes two-stage drying in which preliminary drying is first performed in the latter half of the drum mixer 2b and then main drying is performed in the rotary kiln 3. When such drying is performed, the temperature of the heat medium during the main drying can be made higher than in the case of a drying form in which preliminary drying is not performed. That is, a drying mode in which the heating temperature is gradually increased by using a heating medium of 80 ° C. or higher, preferably 100 ° C. or higher at the time of preliminary drying, while using a heating medium of 200 ° C. or higher at the time of main drying. It is preferable to take The temperature of the heat medium applied to these drying operations may be appropriately determined in consideration of the amount of inorganic binder or organic binder added and the scale of the drying equipment.

  Next, FIG. 8 investigates the influence of the degree of drying of the raw granulated particles on the sinterability of the granulated and sintered raw material after drying, and the result is shown as the moisture content (mass%) of the granulated and sintered raw material. ) And the sintering time (minutes). From this figure, it can be seen that when the water content of the granulated and sintered raw material is 4 mass% or less, the sintering time is rapidly shortened. Therefore, it is necessary to perform the drying with the heating medium until the moisture content of the granulated sintered raw material becomes 4 mass% or less. This is the reason for producing a dry granulated sintered raw material having a water content of 4.0 mass% or less in the present invention. A preferable moisture content is 3 mass% or less, more preferably 2 mass% or less.

  As described above, if the water content in the granulated and sintered raw material can be lowered to 4.0 mass% or less, this can be charged into a sintering machine to burn the charged layer (sintered bed). -Even if a wet zone does not form or is generated below the melt zone, the wet zone size (vertical thickness) can be reduced. As a result, it is possible not only to reduce the airflow resistance due to the generation of the wet zone, but also to improve the sintering speed and improve the production efficiency of the sintered ore. Furthermore, when the sintering operation is performed with the same ventilation resistance, the sintering bed layer thickness (charging layer thickness) can be increased, so that the yield can be improved and the upper layer portion of the charging layer can be improved. Therefore, it becomes possible to reduce the amount of carbonaceous material necessary for the production of sintered ore.

  FIG. 9 shows the relationship between the ratio of the agglomerated material representing the amount of the carbon material and the tumbler strength representing the sintered strength. Usually, when the amount of the carbon material (the agglomerated material) is reduced, the strength of the sintered ore is reduced. Decreases. However, as is clear from FIG. 10 showing the relationship between the layer thickness and the sinter strength (tumbler strength), the ventilation resistance related to the wet zone is reduced, the ventilation resistance of the entire charged layer on the pallet is reduced, and If the bed bed thickness (charge layer thickness) can be increased, the heat of the charge layer upper layer can be used effectively, so the strength of the sintered ore can be increased, and as a result, It is possible to reduce the amount of carbonaceous material necessary for the production of sintered ore.

(3) Examination of heat medium type and drying method When the temperature of the exhaust gas of the drying heat medium used for rolling the particles in a rotary kiln is advanced, the moisture in the granulated particles rapidly evaporates. In addition, the particles may explode (collapse). Furthermore, there is a high possibility that the granulated particles will collapse due to collision between the granulated particles. In this case, it is preferable to use the exhaust gas of the drying heat medium supplied countercurrently from the discharge port side of the rotary kiln after diluting it into hot air at an appropriate temperature.

  Also, when adding a binder in advance to the granulated particles of the sintered raw material containing carbonaceous material, and then granulating by adding granulated water, add preliminary drying to the granulated particles in the latter half of the granulation process, Then, if stirring-drying is performed with the rotary kiln, it effectively acts to prevent explosion during rolling stirring-drying with the rotary kiln.

  Furthermore, the preliminary drying performed in the latter half of the granulator may be a heating operation for raising the temperature of the granulated particles supplied into the rotary kiln. It is possible to reduce or prevent explosion because the granulated particles supplied into the rotary kiln are heated in advance, and the subsequent drying process of the stirring-drying operation using the rotary kiln immediately becomes a drying process. Because.

  In the method of the present invention, a binder and water (post-addition) are mixed with a sintered raw material containing a carbonaceous material, granulated to obtain raw granulated particles, and a part thereof is dried with a rotary kiln. After the water content is reduced to 4.0 mass% or less, the dehydrated part of the dry granulated sintered raw material particles and the remaining undried raw granulated particles are mixed, and then these mixtures are mixed in the pallet of the sintering machine. It is good also as a sintering raw material for charging. That is, in this method, a part of the raw granulated particles is subjected to a drying process by a rotary kiln, and then the obtained dried granulated particles (granulated sintered raw material) are mixed with the raw granulated particles, thereby the drying process. It is effective in reducing the fine powder portion in the granulated and sintered raw material by adhering the collapsed portion of the dry granulated and sintered raw material particles generated in step 1 in the mixing process so as not to harm the sintering.

  The result of the sintering pot test implemented in order to confirm the effect of this invention below is demonstrated based on Table 1. FIG.

(Comparative Example 1)
In this example, quick lime is used as a binder, and the raw material blending and granulation steps in a normal sintering process in which granulated particles are not dried are simulated.

(Comparative Example 2)
In this example, carboxymethyl cellulose (also called methyl cellulose carboxylate, molecular weight of about 80,000 called CMC) is used as a binder, and the binder is added together with water into a granulator (drum mixer). An example is a method following the process shown in FIG. In this method, the granulated and sintered raw material before charging into the sintering machine is smaller than that of Comparative Example 1 and significantly smaller than the diameter of the raw granulated particles before the drying step, and the raw material during dry firing is reduced. Disintegration of the grains is remarkable.
The average air volume during the sintering machine operation experiment is lower than that of Comparative Example 1, which is considered to be caused by a large amount of fine raw material particles closing the voids. As a result, the sintering time is greatly increased, leading to a decrease in production rate.

(Invention Example 1)
In this example, the same organic carboxymethyl cellulose as in Comparative Example 1 is used as a binder, and this binder is first mixed with a sintering raw material, and then water is added and granulated. Fig. 4 is an embodiment according to a process compatible with the present invention shown in Fig. 3; In this example, the granulated and sintered raw material particles before being subjected to the sintering machine operation experiment have a larger particle size than Comparative Example 1 and Comparative Example 2, and the granulated particle size after drying is also Comparative Example 1 and Comparative Example. Compared to 2, it is much larger. Moreover, compared with the comparative example 2, the collapse | disintegration of the granulated particle at the time of a drying process is suppressed significantly. In addition, the average air volume of this example is larger than that of Comparative Example 1 and Comparative Example 2. The reason is considered to be that there are few fine raw material particles that block the voids. As a result of this example, the sintering time is significantly shortened and the production rate is increased.

(Invention Example 2)
In this example, carboxymethyl cellulose was used as the same organic binder as in Comparative Example 1 and Inventive Example 1, and after mixing 0.13 mass% of the used amount together with the sintering raw material, the remaining half of the binder was dissolved. It is the method of granulating by adding the made aqueous solution. In this example, the diameter of the granulated and sintered raw material particles before being subjected to the sintering machine operation experiment is larger than that of Comparative Example 2 and smaller than that of Invention Example 1. The granulated particle size after drying is also larger than that of Comparative Example 2 and smaller than that of Invention Example 1. Therefore, the collapse of the granulated particles at the time of drying was smaller than that of Comparative Example 2 and was larger than that of Invention Example 1.
Note that the charging density and average air volume, exhaust gas maximum temperature, yield, sintering time, and production rate in the sintering machine operation experiment are all intermediate values between Comparative Example 2 and Invention Example 2, and are part of the binder. It has been found that a certain effect can be obtained also by mixing in advance with the sintering raw material used only. The same results were obtained with guar gum or gum arabic where the organic binder used was a cam material.

  From the above results, it is effective to maintain and expand the granulated particle diameter by mixing the binder with the sintering raw material before water-added granulation in advance, ensuring air permeability and productivity during sintering operation. It was found to be effective in maintaining and improving Also, by mixing only a part of the binder to be added to the sintering raw material before the water addition granulation treatment and suspending the remainder in water or adding it together with the water and then granulating the mixture. It was also found that there was an effect of expanding the granulated particle diameter.

  The technique according to the present invention is not only suitably used as a sintering raw material in operation of a wetless sintering machine, but also effective as a sintering raw material for a normal DL sintering machine.

It is a figure which shows the flow of the conventional sintered ore manufacturing process. It is a figure which shows the flow of the conventional granulation sintering raw material manufacturing process. It is a figure which shows the flow of the granulation sintering raw material manufacturing process of this invention. It is a graph which shows the influence of the binder which acts on the particle diameter accumulation ratio before and behind drying of the granulated particle using a rotary kiln. It is a schematic diagram explaining the distribution state of the binder in a powder packed bed. It is a figure explaining the change of the distribution state of the organic binder by the difference in the addition method. It is a figure explaining an effect | action at the time of using together an inorganic binder and an organic binder. It is a graph which shows the influence which the moisture content of granulated particle has on sintering time. It is a graph which shows the relationship between the amount of carbon materials, and a sinter strength. It is a graph which shows the relationship between layer thickness and sinter strength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hopper 2a Drum mixer 2b for mixing Granulator drum mixer 3 Rotary kiln 4 Surge hopper 6 Drum feeder 7 Chute 8 Pallet 9 Charging layer 10 Ignition furnace 11 Wind box

Claims (13)

  In order to produce a granulated sintered raw material by adding a binder and water to the sintered raw material, and drying to produce a granulated sintered raw material, at least a part of the binder is preliminarily mixed with the sintered raw material, and then water is added. A method for producing a granulated and sintered raw material, characterized by performing a granulation process.   The binder is used in a state where 50 mass% or more of the binder is premixed with a sintering raw material and the remaining binder is dissolved in water in advance or suspended without being dissolved in water. Item 2. A method for producing a granulated and sintered raw material according to Item 1. The said binder contains an organic binder, The manufacturing method of the granulation sintering raw material of Claim 1 or 2 characterized by the above-mentioned. The method for producing a granulated and sintered raw material according to claim 3, wherein the organic binder is a gum-based material or a cell-based thickener. The method for producing a granulated and sintered raw material according to claim 4, wherein the gum-based material is guar gum or gum arabic. The method for producing a granulated and sintered raw material according to claim 4, wherein the cell thickener is carboxymethylcellulose. The said binder consists of an organic binder and an inorganic binder, The manufacturing method of the granulation sintering raw material of Claim 1 or 2 characterized by the above-mentioned. The method for producing a granulated and sintered raw material according to claim 7, wherein the inorganic binder is at least one selected from the group consisting of bentonite and water glass. The granulated and sintered raw material according to claim 1 or 2, wherein the water added at the time of granulation is granulated by adding an excessive amount than an appropriate moisture value determined according to the sintered raw material. Production method. The method for producing a sintered ore according to claim 1, wherein a rotary kiln is used for the drying. The method for producing a granulated and sintered raw material according to claim 1 or 10, wherein the drying comprises subjecting the raw granulated particles of the sintered raw material to preliminary drying and then main drying. The method for producing a granulated and sintered raw material according to claim 11, wherein the drying uses a heating medium of 80 ° C for preliminary drying, and a heating medium of 200 ° C or more for the main drying. The method for producing a granulated and sintered raw material according to claim 1, wherein the moisture after drying is 4.0 mass% or less.

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