JP2012067351A - Apparatus and method for manufacturing agglomerate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing agglomerates, capable of effectively utilizing a powder material derived from a raw material produced by an agglomeration machine or a drier when agglomerates are manufactured using the raw material containing an metal oxide-containing substance and a carbonaceous reducing agent, and also to provide a method for manufacturing agglomerates by effectively utilizing the powder material derived from the raw material.SOLUTION: An apparatus for manufacturing agglomerates includes: a mixer mixing a raw material containing an metal oxide-containing substance and a carbonaceous reducing agent; an agglomeration machine agglomerating a mixture obtained by mixing; and a drier drying the agglomerates obtained by agglomerating. The apparatus for manufacturing agglomerates is provided with: a path conveying the powder material derived from the raw material produced by the agglomeration machine to the mixer; and/or a path conveying the powder material derived from the raw material produced by the drier to the mixer.

Description

  The present invention includes a substance containing a metal oxide such as iron ore or chromium oxide (hereinafter sometimes referred to as a metal oxide-containing substance) and a reducing agent containing carbon (hereinafter sometimes referred to as a carbonaceous reducing agent). And a device for producing the agglomerate by agglomerating the obtained mixture with a drier and drying the obtained agglomerate with a drier. It relates to a method of manufacturing. The agglomerate obtained in the present invention can be charged into a heating furnace and heated, and the particulate metal can be produced by reducing the metal oxide in the agglomerate.

  In the present specification, an agglomerate is produced using an iron oxide source such as iron ore or iron oxide as the metal oxide-containing substance, and the description will be made mainly on producing granular metal iron. Is not limited to this. For example, as the metal oxide-containing material, agglomerates are produced using chromium oxide-containing ore or nickel oxide-containing ores, and the agglomerates are heated and reduced to produce ferrochrome or ferronickel. The present invention can be employed. In the present specification, the term “granular” does not necessarily mean a true sphere, but also includes an oval shape, an egg shape, or a flattened shape thereof.

  A direct reduction iron manufacturing method for producing metallic iron from a raw material mixture containing an iron oxide source such as iron ore or iron oxide (hereinafter sometimes referred to as an iron oxide-containing substance) and a carbonaceous reducing agent has been developed. In this iron making method, the agglomerate formed from the raw material mixture is charged into a heating furnace (for example, a moving hearth type heating furnace) and heated in the furnace by gas heat transfer or radiant heat using a heating burner. The iron oxide in the composition can be reduced with a carbonaceous reducing agent to obtain granular metallic iron. The agglomerates used at this time are uniformly mixed with an iron oxide-containing substance and a carbonaceous reducing agent, and, if necessary, combined with an appropriate auxiliary material (for example, a binder) to form aggregates, granules, briquettes, pellets, It can be obtained by molding into an arbitrary shape such as a rod (Patent Document 1).

Japanese Patent Laid-Open No. 9-256017

  In the step of agglomerating the mixture in which the iron oxide-containing substance and the carbonaceous reducing agent are uniformly mixed, a part of the mixture may not be agglomerated and a powdery material derived from the raw material may be generated. In addition, in the step of drying the agglomerate obtained by agglomeration, the agglomerate is dropped from the dryer, or the agglomerates collide with each other and part of the surface is peeled off to produce a powdery product. Sometimes. Such powders have been discarded in the past, but effective utilization of resources is required.

  The present invention has been made paying attention to such circumstances, and its purpose is to produce an agglomerate using a raw material containing a metal oxide-containing substance and a carbonaceous reducing agent. Another object of the present invention is to provide an apparatus for producing an agglomerate that can effectively use a powdery material derived from a raw material produced in a dryer. Another object of the present invention is to provide a method for producing an agglomerate by effectively using the above powdery material.

  An apparatus for producing agglomerates according to the present invention that has solved the above problems is a mixer for mixing raw materials containing a metal oxide-containing substance and a carbonaceous reducing agent, and agglomerates the mixture obtained by mixing. An agglomerating machine, and a manufacturing apparatus equipped with a dryer for drying the agglomerated material obtained by agglomeration, and transporting the raw material-derived powdered material produced in the agglomerator to the mixer It has a gist in that a path and / or a path for conveying the powdery material derived from the raw material generated in the dryer to the mixer are provided.

  The dryer may further include a dust remover and a path for conveying the powder collected by the dust remover to the mixer.

  The manufacturing apparatus further includes a classifier and a heating furnace, and supplies the agglomerate obtained by the dryer to the classifier, and supplies coarse particles separated by the classifier to the heating furnace. It is preferable to provide a path for conveying the fine particles separated by the path and the classifier to the mixer.

  The conveyance path may further include a pulverizer. A fixed amount feeder may be further provided between the pulverizer and the mixer.

  The mixer may include a first mixer that mixes at least the carbonaceous reducing agent, and a second mixer that mixes the mixture obtained in the first mixer and at least the metal oxide-containing substance. .

  The method for producing an agglomerate according to the present invention that has solved the above-mentioned problem is to mix a raw material containing a metal oxide-containing substance and a carbonaceous reducing agent in a mixer and mix the mixture obtained by mixing. The agglomerate is agglomerated by an agglomerator, and the agglomerate obtained by agglomeration is dried by a drier to produce an agglomerate, wherein the powdery material derived from the raw material produced by the agglomerator is It has a gist in that it is conveyed to a mixer and / or a powdery substance derived from the raw material generated in the dryer is conveyed to the mixer.

  It is preferable that the powder collected by the dust remover provided in the dryer is conveyed to the mixer.

  The agglomerate obtained by the dryer is supplied to a classifier and divided into coarse particles and fine particles, the coarse particles divided by the classifier are supplied to a heating furnace, and the fine particles separated by the classifier are supplied. It is preferable to convey the grains to the mixer.

  It is preferable that the conveyed product to the mixer is, for example, pulverized to a particle size of 3 mm or less with a pulverizer and then conveyed to the mixer.

  The ratio of the conveyed product to the mixer occupying the mass of the agglomerated material is preferably 5% or more, for example.

  As the mixer, it is preferable to use a first mixer that mixes at least a carbonaceous reducing agent, and a second mixer that mixes the mixture obtained in the first mixer and at least a metal oxide-containing substance.

  According to the present invention, when an agglomerate is produced using a mixer, an agglomerator, and a dryer, a powdery material derived from the raw material generated in the agglomerator and / or the dryer is conveyed to the mixer. Therefore, powdery materials derived from raw materials that have been discarded can be used effectively. Accordingly, waste disposal is not necessary, and the burden on the environment can be reduced.

FIG. 1 illustrates an example of a process for producing an agglomerate from a raw material containing a metal oxide-containing substance and a carbonaceous reducing agent, and charging the agglomerate into a heating furnace to produce a granular metal. FIG. FIG. 2 illustrates another example of a process for producing an agglomerate from a raw material containing a metal oxide-containing substance and a carbonaceous reducing agent, and charging the agglomerate into a heating furnace to produce a granular metal. FIG.

  In the production of agglomerates using a mixer, agglomerator, and dryer, the present inventors have made a powder-derived material derived from raw materials produced in agglomerators and / or dryers that were conventionally discarded. We have been intensively studying how to use it effectively as a resource. As a result, it can be reused as a part of the raw material by transporting the powdery substance derived from the raw material generated in the agglomerator or the dryer to the mixer, and even if the powdery substance is used as a part of the raw material It has been found that the physical properties (eg, apparent density and strength) of the agglomerate and the properties of the granular metal obtained by heating and reducing this agglomerate (eg, yield rate, component composition) are not adversely affected. Completed the invention. The present invention will be described below.

  The agglomerate manufacturing apparatus according to the present invention includes a mixer, an agglomerator, and a dryer. In particular, the raw material-derived powder generated in the agglomerator and / or the dryer is It is characterized in that it has a path for conveying to the mixer. Using this manufacturing device, an agglomerate is produced from a raw material containing a metal oxide-containing substance and a carbonaceous reducing agent, and after classifying the agglomerate, heat reduction is performed to produce a granular metal. This will be described with reference to FIG.

  In FIG. 1, 1a is a metal oxide-containing substance supply means, 1b is a carbonaceous reducing agent supply means, 1c is a binder supply means, 2 is a mixer, 3 is an agglomerator, 4 is a dryer, 5 is a classifier, 6 Denotes a heating furnace, and 7 denotes a dust remover.

  The metal oxide-containing substance supply means 1a, the carbonaceous reductant supply means 1b, the binder supply means 1c and the mixer 2 are connected by a path 100, and the mixer 2 and the agglomerator 3 are connected to the path 101, the agglomerator 3 The dryer 4 is connected to the route 102, and the dryer 4 and the classifier 5 are connected to the route 103, respectively. Reference numeral 104 denotes a path for conveying the powder derived from the raw material generated in the agglomerator 3 to the mixer 2, and 105 denotes a path for conveying the powder derived from the raw material generated in the dryer 4 to the mixer. .

  The procedure for producing the granular metal using the raw material containing the metal oxide-containing substance and the carbonaceous reducing agent is as follows (1) to (4).

  (1) First, a raw material containing a metal oxide-containing substance and a carbonaceous reducing agent is supplied to the mixer 2 through the path 100 and mixed.

  (2) Next, the mixture obtained by mixing in the mixer 2 is supplied to the agglomerator 3 through the path 101 and agglomerated. The powdery material derived from the raw material generated in the agglomerator 3 is conveyed to the mixer 2 through the path 104. By conveying the powdery material to the mixer 2, the powdery material can be effectively used as a resource.

  (3) Next, the agglomerate obtained by agglomeration by the agglomerator 3 is supplied to the dryer 4 through the path 102 and dried. The powdery material derived from the raw material generated in the dryer 4 is conveyed to the mixer 2 through the path 105. By conveying the powdery material to the mixer 2, the powdery material can be effectively used as a resource.

  The agglomerate manufacturing apparatus according to the present invention includes the mixer, the agglomerator, and the dryer. The dryer 4 is provided with a dust remover 7 as shown in FIG. May be. The gas in the dryer 4 is extracted from the path 106, the powder contained in this gas is recovered by the dust remover 7, and the recovered powder is conveyed to the mixer 2 through the path 107. By conveying the powder to the mixer 2, the powder can be effectively used as a resource.

  (4) The agglomerate obtained by drying with the dryer 4 may be supplied to the classifier 5 through the path 103 and separated into coarse particles and fine particles. The coarse particles separated by the classifier 5 can be supplied to the heating furnace 6 through the path 108 and heated and reduced to produce granular metal. On the other hand, the fine particles separated by the classifier 5 may be discharged out of the system, but may be conveyed to the mixer 2 through a path 109 as shown in FIG. By conveying the fine particles to the mixer 2, the fine particles can be effectively used as resources.

  Hereafter, each procedure of said (1)-(4) is demonstrated in detail.

  (1) As said metal oxide containing substance, a chromium oxide containing ore, a nickel oxide containing ore, an iron oxide containing substance, etc. can be used. As the iron oxide-containing substance, for example, iron ore, iron sand, steelmaking dust, nonferrous smelting residue, ironmaking waste, and the like can be used. If the dust produced during the melting of stainless steel is used as a steelmaking dust together with an iron oxide source such as iron ore or mill scale, valuable metals such as Ni, Cr, and Mo contained in the dust are taken into the granular iron. It can be efficiently recovered in the state.

  As the carbonaceous reducing agent, a reducing agent containing carbon may be used. For example, coal or coke can be used.

  In order to increase the strength of the agglomerate, a binder is usually added to the mixture containing the metal oxide-containing substance and the carbonaceous reducing agent. What is necessary is just to supply a binder to the mixer 2 from the path | route 100, as shown in FIG. As the binder, for example, polysaccharides (for example, starch such as corn starch and wheat flour) can be used.

As other components, in addition to the binder, an MgO-containing material, a CaO-containing material, or the like may be added to the above mixture. What is necessary is just to supply MgO containing material, CaO containing material, etc. to the mixer 2 from the path | route 100. FIG. As the MgO-containing substance, for example, an MgO-containing substance extracted from MgO powder, natural ore, seawater, etc., dolomite, magnesium carbonate (MgCO ₃ ), or the like can be used. As the CaO-containing substance, for example, quick lime (CaO) or limestone (main component is CaCO ₃ ) can be used.

  As the mixer 2, for example, a rotary container mixer or a fixed container mixer can be used. As the rotary container type mixer, for example, a rotary cylinder type, double cone type, V type mixer or the like can be used. As the fixed container mixer, for example, a mixer provided with rotating blades (for example, a bowl) in a mixing tank can be used.

  In the mixer 2, the raw materials are preferably mixed in a dry state. By mixing in a dry state, the raw materials can be mixed uniformly. A dry state means that the moisture content of the raw material supplied into the mixer 2 is 1% or less.

  In order to perform mixing in the mixer 2 in a dry state, the dried raw material may be supplied to the mixer 2.

  (2) When the mixture is agglomerated, a part of the mixture may not be agglomerated and a powdery material derived from the raw material may be generated. This powder has been discarded. On the other hand, in this invention, the powdery material derived from the said raw material produced with the agglomeration machine 3 is conveyed to the mixer 2 through the path | route 104. FIG. In the mixer 2, the powder derived from the raw material supplied from the path 104 and the raw material supplied through the path 100 from the metal oxide-containing substance supply means 1 a, the carbonaceous reducing agent supply means 1 b, and the binder supply means 1 c By mixing, the powdery material derived from the raw material can be effectively used as a resource.

  Before the raw material-derived powder produced in the agglomerator 3 is conveyed to the mixer 2, moisture may be adjusted. That is, since the powdery material derived from the raw material generated in the agglomerator 3 contains about 5 to 15% by mass of water, the powdery material is directly conveyed to the mixer 2 and contains the metal oxide. When mixed with the raw material supplied from the substance supply means 1a or the like, it may not be possible to mix uniformly. It is recommended that the powdery material derived from the raw material generated in the agglomerator 3 is adjusted to a moisture content of, for example, less than 5% by mass before being conveyed to the mixer 2.

  In order to adjust the moisture of the powder derived from the raw material generated in the agglomerator 3, the powder is supplied to a dryer (not shown) and dried, or is piled and dried in the sun. Just do it.

  As the agglomerator 3 used when agglomerating the above mixture, for example, a dish granulator (disk granulator), a drum granulator (cylindrical) granulator, or the like can be used. .

  If necessary, the agglomerator 3 may be provided with moisture supply means to agglomerate the raw material while adding water.

  The shape of the agglomerate is not particularly limited, and may be, for example, a lump shape, a granular shape, a briquette shape, a pellet shape, a rod shape, or the like, and preferably a pellet shape or a briquette shape.

  (3) When drying the agglomerate, the agglomerate falls off while moving in the dryer 4, or the agglomerates collide with each other and part of the surface is peeled off, resulting in a powdery material derived from the raw material May occur. This powder has been discarded. On the other hand, in this invention, the powdery material derived from a raw material is conveyed to the mixer 2 through the path | route 105. FIG. In the mixer 2, the powder derived from the raw material supplied from the path 105 is mixed with the raw material supplied through the path 100 from the metal oxide-containing substance supply means 1a, the carbonaceous reducing agent supply means 1b, and the binder supply means 1c. By doing so, the powdery material derived from the raw material can be effectively used as a resource.

  When the powder derived from the raw material generated in the dryer 4 is transported to the mixture 2 and reused as a resource, the binder supply means supplies about 1% by weight of binder to the mass of the powder to be transported. It is recommended to feed the mixer 2 from 1c. Since the binder contained in the powder derived from the raw material produced in the dryer 4 does not exhibit the effect of improving the strength of the agglomerate, the strength of the agglomerate is increased by blending a new binder as the raw material. is there.

  As the dryer 4, for example, an aeration band dryer or the like can be used. The aeration band dryer is a device that dries with hot air while being transported through the dryer while being placed on a conveyor, and the band is usually made of wire mesh. The agglomerate that has fallen off from the dryer 4 and the powdered material derived from the raw material that has been peeled off from the surface of the agglomerated material are collected by a hopper provided under the band. It is conveyed to.

  Although the conditions when drying the said agglomerate with the said dryer 2 are not specifically limited, For example, what is necessary is just to heat and dry to 100-200 degreeC.

  The dryer 4 may be provided with a dust remover 7 as shown in FIG. The gas in the dryer 4 is extracted from the path 106, the powder contained in this gas is recovered by the dust remover 7, and the recovered powder is conveyed to the mixer 2 through the path 107. By conveying the powder to the mixer 2 and mixing it with the raw material, the powder can be effectively used as a resource.

  As the dust remover 7, for example, a cyclone type dust collector or a bag filter type dust collector can be used.

  A path 104 for conveying the powder derived from the raw material generated in the agglomerator 3 to the mixer 2 and a path 105 for conveying the powder derived from the raw material generated in the dryer 4 to the mixer 2 are as follows: By providing either one, the powdery material derived from the raw material conventionally discarded can be used effectively as a resource. Preferably, both the path 104 and the path 105 are provided.

  (4) The agglomerate obtained by the dryer 4 is supplied to the classifier 5 and divided into coarse particles and fine particles.

  As the classifier 5, a screen or an air classifier can be used. As the screen, for example, a roller screen can be used. A roller screen is a device in which a plurality of rollers that can rotate around an axis are arranged in parallel, and these rollers form an inclined surface. Each roller is configured so that the roller interval can be adjusted. The distance between the rollers arranged on the upstream side of the roller screen was narrowed (for example, 8 to 10 mm), the distance between the rollers arranged on the downstream side was widened (for example, 10 to 20 mm), and the dryer 4 was obtained. By supplying the agglomerate from the upstream side of the roller screen, the agglomerate is divided into coarse grains and fine grains while moving on the inclined surface. That is, the agglomerate that has passed through the gap between the rollers arranged on the upstream side of the roller screen is collected as fine particles, and the agglomerate that has passed through the gap between the rollers arranged on the downstream side is collected as coarse particles. In addition, what is necessary is just to discharge | emit the super coarse agglomerate which does not pass the clearance gap of the roller arrange | positioned downstream from the system from the most downstream side of a roller screen. The ultra coarse agglomerate discharged out of the system may be crushed by a crusher and then conveyed to the mixer 2.

  The particle size threshold when separating into coarse and fine particles by the classifier 5 is as follows. Handling of the agglomerated material after classification, and heating and reducing the agglomerated material after classification in a heating furnace produce a granular metal. What is necessary is just to determine in consideration of the production efficiency when doing so. That is, a coarse grain is an agglomerate having a size that can be suitably used when producing a granular metal, and a fine grain means debris or powder derived from the agglomerate.

  The threshold value of the particle size may be 6 to 10 mm, for example. The particle size (maximum diameter) can be measured with, for example, a caliper. The threshold value is a reference value when classifying coarse particles and fine particles. For example, when the threshold value is set to 10 mm, particles having a particle size of 10 mm are arranged on the coarse particle side and fine particle side. The value which isolate | separates so that it may become 1: 1 by mass ratio is meant.

  The coarse particles separated by the classifier 5 are supplied to the heating furnace 6, and the fine particles are conveyed to the mixer 2.

《About coarse particles》
As the heating furnace 6, a moving hearth type heating furnace can be used in addition to a batch type heating furnace. The moving hearth type heating furnace is a heating furnace in which the hearth moves in the furnace like a belt conveyor, and specifically, a rotary hearth furnace can be exemplified. The rotary hearth furnace is designed in a circular shape (donut shape) so that the start point and end point of the hearth are the same, and the agglomerate supplied on the hearth is Is heated and reduced to make a granular metal. Therefore, the charging means for supplying the agglomerate into the furnace is arranged on the most upstream side in the rotation direction, and the most downstream side in the rotation direction (because of the rotating structure, it is actually just upstream of the charging means. A discharge means is provided on the side.

  Conditions for heating and reducing the agglomerate in the heating furnace are not particularly limited, and known conditions may be employed. For example, what is necessary is just to heat and reduce so that the said agglomerate may be 1200-1500 degreeC. For heating in the heating furnace, the temperature of the agglomerate can be adjusted by using a burner and controlling the combustion conditions of the burner.

  In order to protect the hearth from the molten slag and promote reduction of the metal oxide contained in the agglomerate, a carbonaceous material is usually laid on the hearth of the heating furnace 6 as a flooring material. Prior to supplying the agglomerate to the hearth, the carbonaceous material is preferably laid on the hearth in advance.

  The thickness of the floor covering material is not particularly limited, but is preferably 3 to 30 mm, for example.

  As the carbon material used as the floor covering material, those exemplified as the carbonaceous reducing agent can be used. It is recommended that the carbonaceous material used as the flooring material has a particle size of about 0.5 to 3.0 mm.

  The granular metal obtained in the heating furnace 6 can be charged into a steelmaking furnace and used as an iron source. An example of the steel making furnace is an electric furnace.

《About fine grains》
On the other hand, the fine particles separated by the classifier 5 can be effectively used as resources by being transported to the mixer 2 and mixed with the raw materials.

  When the average particle diameter of the conveyed product to the said mixture 2 is 0.5 mm or more, you may reduce the amount of binders supplied from the binder supply means 1c according to the ratio of the conveyed product with respect to the mass of an agglomerate. Of the fine particles, a coarse transported material having an average particle size of 0.5 mm or more is mixed with the raw material supplied from the metal oxide-containing substance supply means 1a, the carbonaceous reducing agent supply means 1b, and the binder supply means 1c. This is because, when agglomerated, the coarse transported material becomes a production nucleus of the agglomerated material, so that the amount of binder necessary for agglomeration can be reduced.

  As described above, using the agglomerate manufacturing apparatus according to the present invention, an agglomerate is produced from a raw material containing a metal oxide-containing substance and a carbonaceous reducing agent, and after the agglomerate is classified, it is heated and reduced to be granular. The process of manufacturing a metal has been described.

  Next, another configuration example of the agglomerate manufacturing apparatus according to the present invention will be described with reference to FIG. The same reference numerals are assigned to portions corresponding to those in FIG.

  In FIG. 2, a first mixer 2a and a second mixer 2b are provided instead of the mixer 2 shown in FIG. The first mixer 2a and the second mixer 2b are connected by a path 101a, and the second mixer 2b and the agglomerator 3 are connected by a path 101b. The agglomerator 3 is a path 104 for transporting powders derived from the raw material, the dryer 4 is a path 105 for transporting powders derived from the raw material, the classifier 5 is a path 109 for transporting separated fine particles, and dust removal The machines 7 are connected to the first mixer 2a through paths 107 for conveying the collected powder. Moreover, in FIG. 2, the powder derived from the raw material produced in the agglomerator 3 and / or the dryer 4, fine particles separated by the classifier 5, and the powder recovered by the dust remover 7 are used as the first mixer. The crusher 8 is provided in the path | route conveyed to 2a, and the fixed_quantity | feed_rate supply machine 9 is provided between the crusher 8 and the 1st mixer 2a. Further, in FIG. 2, the carbonaceous reducing agent supply means 1b and the binder supply means 1c are connected to the first mixer 2a via a path 100, and the metal oxide-containing substance supply means 1a is connected to the second mixer 2b via a path 110. Connected. The second mixer 2b is provided with a path 111 for supplying moisture.

  As shown in FIG. 2, by providing a pulverizer 8 in the conveyance path (paths 104, 105, 107, and 109), the material to be conveyed from the agglomerator 3, the dryer 4, the classifier 5, or the dust remover 7. The particle size can be adjusted appropriately. That is, since the particle size of the conveyed product from the agglomerator 3, the dryer 4, the classifier 5, or the dust remover 7 varies, the agglomerate is reduced by heating if the conveyed material is mixed with the raw material as it is. As a result, unevenness is likely to occur in the quality of the granular metal obtained. Therefore, it is recommended that the conveyed product be crushed by the pulverizer 8 and then conveyed to the first mixer 2a.

  FIG. 2 shows an example in which the pulverizer 8 is arranged so that all the conveyed items from the agglomerator 3, the dryer 4, the classifier 5 and the dust remover 7 can be crushed by the pulverizer 8. The invention is not limited to this, and a plurality of pulverizers are provided in each conveyance path in order to crush the conveyed product from the agglomerator 3, the dryer 4, the classifier 5, or the dust remover 7 alone. Also good.

  In particular, it is recommended that the pulverizer 8 be arranged so that at least the conveyed product from the dryer 4 can be crushed. In many cases, the conveyed product from the dryer 4 is formed into a small lump by agglomerating the raw materials of the powdery material. Therefore, the particle size of the conveyed product from the dryer 4 tends to be larger than the particle size of the conveyed product from the agglomerator 3, the classifier 5, or the dust remover 7.

  The conveyed product is preferably pulverized by a pulverizer 8 to a particle size of 3 mm or less. By controlling the conveyed product to a particle size of 3 mm or less, it can be uniformly mixed with the raw material supplied through the path 100 from the metal oxide-containing substance supply means 1a, the carbonaceous reductant supply means 1b, and the binder supply means 1c. The properties and quality of the granular metal obtained by heating and reducing the product can be improved.

  For example, a roll crusher or a roller mill can be used as the pulverizer 8.

  Further, a fixed amount feeder 9 is provided in the transport path, and a supply amount when the transported material from the agglomerator 3, the dryer 4, the classifier 5 or the dust remover 7 is supplied to the first mixer 2a. Is preferably adjusted. When the ratio of the transported material to the agglomerate suddenly increases, the amount of transported material that forms the agglomerate rapidly increases, making it difficult to form large agglomerates, and the agglomeration capacity of the agglomerator is reduced. It is because it may fall. Therefore, it is recommended to control the blending ratio of the conveyed product with respect to the raw material by providing a quantitative feeder 9 in the conveying path.

  The ratio of the conveyed product to the mass of the agglomerated material is preferably 5% or more, for example. This is because if the proportion of the conveyed product is too low, effective utilization of the conveyed product cannot be promoted. The upper limit of the mixture ratio of a conveyed product is not specifically limited, What is necessary is just to adjust a mixture ratio in the range which can be agglomerated. In addition, since the powdery material derived from the raw material produced in the dryer 4 is heated for drying, the binder contained in the powdery material does not contribute to the improvement of the strength of the agglomerated material. Therefore, in order to ensure the strength of the agglomerated material, it is recommended that the upper limit of the blending ratio of the raw material-derived powder generated in the dryer 4 is about 15%.

  For example, a loss-in-weight type quantitative feeder may be used as the quantitative feeder 9. A belt feeder, a screw feeder, a vibration feeder, etc. can be used as a feeder used for a loss-in-weight type quantitative feeder. Among these feeders, it is recommended to use a screw feeder or a vibration feeder. When a screw feeder or a vibration feeder is used, the amount of dust generated can be reduced as compared with the case where a belt feeder is used.

  As shown in FIG. 2, the quantitative supply 9 is preferably provided between the pulverizer 8 and the first mixer 2 a. In the case where the pulverizer 8 is not provided, a fixed quantity feeder 9 may be provided between the agglomerator 3, the dryer 4, the classifier 5, or the dust remover 7 and the first mixer 2a.

  In the first mixer 2a, it is preferable to mix at least a carbonaceous reducing agent, and in the second mixer 2b, the mixture obtained in the first mixer 2a and at least the metal oxide-containing substance are mixed. That is, the ratio of the metal oxide-containing substance in the agglomerate is approximately 70%, and the ratio of raw materials other than the metal oxide-containing substance (that is, carbonaceous reducing agent, binder, etc.) is approximately 30%. is there. Therefore, in the first mixer 2a, a material having a low ratio in the agglomerates is mixed uniformly, and the mixture is mixed with a metal oxide-containing substance, whereby the raw materials can be mixed uniformly. it can.

  It is recommended to supply water from the path 111 to the second mixer 2b. This is because the powder in the dry state is difficult to agglomerate and is brittle even when agglomerated, so that it tends to collapse.

  The amount of water supplied from the path 111 is preferably adjusted so that the moisture content in the agglomerate is about 10 to 15%.

  By the way, the metal oxide-containing substances include those in a dry state with a moisture content of 1% or less and those in a moisture state with a moisture content exceeding 7%, depending on the production area, mining status, presence or absence of a beneficiation treatment, and its method. It is known. On the other hand, carbonaceous reducing agents and binders are usually dried. Therefore, when a wet state metal oxide-containing material is mixed with a dry state carbonaceous reducing agent, binder, or the like, the metal oxide-containing material, the carbonaceous reducing agent, and the binder are not easily mixed uniformly. Therefore, when the wet metal oxide-containing substance is used, as shown in FIG. 2, the first mixer 2a and the second mixer 2b are provided, and the first mixer 2a is carbonaceous in a dry state. It is recommended that the reducing agent is mixed with a binder, auxiliary materials, etc., and in the second mixer 2b, the mixture obtained in the first mixer 2a and the metal oxide-containing substance are mixed in a wet state. Of course, a carbonaceous reducing agent, binder, auxiliary material, etc. may be further supplied to the second mixer 2b.

  As described above, according to the present invention, since a path for conveying the powdery material derived from the raw material generated in the agglomerator 3 and / or the dryer 4 to the mixer is provided, resources that have been discarded in the past can be disposed. Effective use.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention. In this example, in the invention example and the comparative example, the powdery material derived from the raw material generated in the agglomerating machine is not used as the raw material of the agglomerated material as the conveyed product.

  An agglomerate was produced by the following procedure, and this was heated and reduced in a heating furnace to produce granular metallic iron.

  First, the agglomerate was produced by the following procedure. The iron ore powder (average particle diameter 30 μm) having the component composition shown in Table 1 below, the coal powder (average particle diameter 20 μm) having the component composition shown in Table 2 below, the organic binder, and the auxiliary material were mixed with a mixer. As the organic binder, starch (average particle size 10 μm) was used, and as the auxiliary material, limestone powder (average particle size 10 μm) and dolomite powder (average particle size 20 μm) were used.

  The obtained mixture was supplied to an agglomerator to produce an agglomerate. The composition of the raw materials contained in the agglomerate is shown in Table 3 below. No. shown in Table 3 below. 1 is a comparative example, and does not mix the conveyed product (that is, the powder derived from the raw material produced in the dryer described later, the powder collected by the dust remover, and the fine particles separated by the classifier) It is an example. On the other hand, no. 2 is an example of the invention, in which the conveyed product (average particle size 1 mm) was blended so as to be 10% with respect to the mass of the agglomerated material. The particle size distribution of the conveyed product is shown in Table 4 below.

Next, the obtained agglomerate was supplied to a dryer and dried. The powdery material derived from the raw material produced in the dryer was conveyed to the mixer (invention example only). Further, the dryer was equipped with a dust remover, and the powder collected by the dust remover was conveyed to the mixer (invention example only). The apparent density of the dried agglomerate is no. 1 is 2.24 g / cm ³ , No. 1 2 was 2.30 g / cm ³ . The strength of the dried agglomerate was evaluated by a crushing load according to ISO 4700. As a result, no. The crushing load of No. 1 is 30 kg / piece, no. The crushing load of 2 was 32 kg / piece. One piece means one agglomerate.

  Next, the dried agglomerate was supplied to a classifier and divided into coarse particles and fine particles. The threshold value of the particle size for separating coarse particles and fine particles was 8 mm. The fine particles separated by the classifier were conveyed to the mixer (invention example only).

  Next, the coarse particles separated by the classifier were charged into a laboratory-scale small heating furnace (furnace temperature 1450 ° C.), heated and reduced, and further melted to produce granular metallic iron and slag.

  The iron purity of the obtained granular metallic iron was No. 1 is 95.9%. 2 was 95.8%.

The production yield rate of granular metallic iron is No. No. 1 is 100.3%. 2 was 99.4%. In addition, the production | generation yield rate of granular metallic iron is computed by a following formula. Since the granular metallic iron includes carbon and the like, the production yield rate of the granular metallic iron may exceed 100%.
Production yield rate of granular metallic iron (%) = [mass of produced granular metal having a grain size of 3.35 mm or more / mass of iron in raw material] × 100

  From the above results, the physical properties (apparent density, strength) of the agglomerates and the quality (iron purity, production yield rate) of the granular metal iron can be obtained by mixing the transported materials with the raw materials even if the transported materials are blended with the raw materials. It turns out that it hardly deteriorates compared with the case where it does not mix | blend with. Therefore, according to the example of the present invention, the transported goods that have been discarded can be effectively used as resources.

1a Metal oxide-containing substance supply means 1b Carbonaceous reducing agent supply means 1c Binder supply means 2 Mixer 2a First mixer 2b Second mixer 3 Agglomerator 4 Dryer 5 Classifier 6 Heating furnace 7 Dust remover 8 Crusher 9 Metering machine

Claims (12)

A mixer for mixing raw materials containing a metal oxide-containing substance and a carbonaceous reducing agent, an agglomerator for agglomerating the mixture obtained by mixing, and drying for drying the agglomerate obtained by agglomeration An agglomerate manufacturing apparatus equipped with a machine,
Provided with a path for conveying the raw material-derived powdery material generated in the agglomerator to the mixer and / or a path for conveying the raw material-derived powdery material generated in the dryer to the mixer. An agglomerate manufacturing apparatus characterized by comprising:   The manufacturing apparatus according to claim 1, further comprising a dust remover in the dryer, and a path for conveying the powder collected by the dust remover to the mixer.   Further, a classifier and a heating furnace are provided, a path for supplying the agglomerate obtained by the dryer to the classifier, a path for supplying coarse particles separated by the classifier to the heating furnace, the classifier The manufacturing apparatus of Claim 1 or 2 provided with the path | route which conveys the fine grain divided | segmented by (2) to the said mixer.   The manufacturing apparatus according to claim 1, further comprising a pulverizer in the conveyance path.   The manufacturing apparatus according to claim 4, further comprising a quantitative feeder between the pulverizer and the mixer.   The said mixer is equipped with the 1st mixer which mixes a carbonaceous reducing agent at least, and the 2nd mixer which mixes the mixture obtained by the said 1st mixer, and a metal oxide containing material at least. The manufacturing apparatus in any one of 1-5. A raw material containing a metal oxide-containing substance and a carbonaceous reducing agent is mixed with a mixer, and the mixture obtained by agglomeration is agglomerated with an agglomerator, and the agglomerate obtained by agglomeration is a dryer. A method of producing an agglomerate by drying,
The raw material-derived powder generated in the agglomerator is conveyed to the mixer and / or the raw material-derived powder generated in the dryer is conveyed to the mixer. A manufacturing method for agglomerates.   The manufacturing method of Claim 7 which conveys the powder collect | recovered with the dust remover provided in the said dryer to the said mixer.   The agglomerate obtained by the dryer is supplied to a classifier and divided into coarse particles and fine particles, the coarse particles divided by the classifier are supplied to a heating furnace, and the fine particles divided by the classifier The manufacturing method of Claim 7 or 8 which conveys to the said mixer.   The manufacturing method according to any one of claims 7 to 9, wherein the conveyed product to the mixer is pulverized to a particle size of 3 mm or less by a pulverizer and then conveyed to the mixer.   The manufacturing method in any one of Claims 7-10 which makes the ratio of the conveyed product to the said mixer to the mass of the said agglomerate 5% or more.   The said mixer uses the 1st mixer which mixes a carbonaceous reducing agent at least, and the 2nd mixer which mixes the mixture obtained by the said 1st mixer, and a metal oxide containing material at least. The manufacturing method in any one of 11.

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