JP2004250780A - Agglomerated material of metal-containing powdery waste, method of agglomerating the same, and method of treating the agglomerated material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of easily agglomerating metal-containing powdery waste such as steel manufacturing dust in a high yield with prescribed quality in a short time without depending on weather. <P>SOLUTION: At the time of agglomerating steel manufacturing dust, metal-containing powdery waste, a material having latent hydraulic properties and one or more of alkali stimulants selected from the oxides, hydroxides, carbonates and silicates of alkali metals and the oxides, hydroxides, carbonates and silicates of alkaline-earth metals are kneaded, and the kneaded material is hardened by the latent hydraulic properties of the material having latent hydraulic properties. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to agglomerates of metal-containing powdery wastes, and more particularly to agglomeration of metal-containing powdery wastes after agglomeration to a strength that can be processed in a shaft furnace or a converter with good yield. The present invention relates to a method for agglomerating metal-containing powdery waste and a method for treating the metal-containing powdery waste.

  Some dusts generated in steelworks contain useful metals other than iron, such as steelmaking dusts. Also, in a plating step, a rolling step, a pickling step, etc., similarly, plating sludge, rolled sludge, and pickling sludge containing useful metals are generated.

  For example, dust generated during the production of stainless steel contains, in addition to iron, oxides of very useful metals such as Cr and Ni. Even if they try to reuse them, most of them scatter and become dust again and cannot be used efficiently. Therefore, if the steelmaking dust containing a useful metal can be agglomerated and the agglomerated steelmaking dust can be treated in a shaft furnace or a converter, not only will the resources be effectively used, but also the environment will be protected.

  Recovering metals from metal-containing powdery wastes containing useful metals is a very important technology from the viewpoint of effective use of resources and environmental conservation, and various studies have been conducted so far. Has been done.

  Incidentally, the collected steelmaking dust is in the form of powder and granules, and contains moisture. Therefore, a binder material such as bentonite or lime is mixed with steelmaking dust generally containing a useful metal, agglomerated with a pelletizer, etc., and the steelmaking dust after agglomeration is converted into a converter type furnace. Smelting reduction.

  However, in the conventional agglomeration technique described above, a method of adding a material exhibiting a binder effect such as lime and agglomerating the mixture with a pelletizer or the like requires equipment cost and binder purchase cost. There was a problem that the cost was high.

  In addition, when using ordinary Portland cement having hydraulic properties when agglomerating steelmaking dust, if the Portland cement ratio is 10% by mass, the material kneaded with steelmaking dust is completely removed the day after kneading. It hardens and the strength of the cured product becomes too high, it is difficult to adjust the size to a range of 5 to 50 mm by pulverization, and if the Portland cement ratio is reduced to 5% by mass, The following day, though solidified, the rate of generation of powder with a size of less than 5 mm increases when the cured product is crushed, and the yield of agglomerates with a size of 5 to 50 mm is less than 60% There is. For this reason, when agglomerating steelmaking dust, ordinary Portland cement cannot be used.

  Japanese Patent Application Laid-Open No. 2001-316731 discloses that steelmaking dust, which is ironmaking dust containing useful metallic iron, is mixed with powder such as dust and sludge generated in the ironmaking process, and this mixture is air-mixed. There is disclosed a method of agglomerating by holding the steel inside and oxidizing metallic iron in the mixture (Patent Document 1).

In the case of this method, since the steelmaking dust generated in the steel mill is used as a material that exhibits the agglomeration effect by the binding reaction, the cost for external purchase of the binder and the like is not required, and the equipment for agglomerating with a pelletizer or the like. There are also advantages that do not require.
JP 2001-316731 A

  However, as described in JP-A-2001-316731, powder such as dust or sludge generated in the iron-making process, and steel-making dust containing metallic iron are mixed to agglomerate the iron-made powder. Since the method uses an exothermic oxidation reaction of metallic iron contained in steelmaking dust in the atmosphere, a period of about three weeks is required as a bonding reaction period for oxidizing the entire amount of metallic iron. There is a disadvantage that the agglomeration period for agglomerating the product is long.

  In addition, in this method, since the oxidation reaction of metallic iron in the mixture is used, the progress of oxidation is greatly different depending on the presence or absence of rainwater, etc., when held in the open air, and as a result, variation occurs during the period of agglomeration. In many cases, there is a problem that the degree of agglomeration varies from place to place in the mixture.

  The present inventors have disclosed an agglomeration method that utilizes the oxidative exothermic reaction of metallic iron in a mixture by exposing iron-making dust to the atmosphere as described in JP-A-2001-316731. Agglomerated products are likely to vary, while trying to achieve both the specified strength and the specified yield requires extra work in response to changes in the climate. It was considered difficult to implement it in a practical manner.

  In addition, the conventional agglomeration technique described above involves adding a substance exhibiting a binder effect, such as lime, and agglomerating the mixture using equipment such as a pelletizer to perform agglomeration. There is a problem that costs are high.

  The present invention is based on the above-mentioned policy, and solves the above-mentioned problems of the prior art, and stabilizes metal-containing powdery waste such as steelmaking dust, regardless of climate, with good yield, at a predetermined quality and for a short time. It is an object of the present invention to provide a method for agglomerating easily and easily.

  The present invention is as follows.

  (1) Pulverulent metal-containing waste and substances having latent hydraulic properties, and oxides, hydroxides, carbonates, silicates, and alkaline earth metal oxides, hydroxides, carbonates, and silicates of alkali metals An agglomerate of metal-containing powdery waste, comprising at least one alkali stimulant selected from salts and cured by the hydraulic property of the substance having latent hydraulic property.

  (2) metal-containing powdery waste, substances having latent hydraulic properties, and alkali metal oxides, hydroxides, carbonates, silicates, alkaline earth metal oxides, hydroxides, carbonates, The metal-containing powdery waste according to (1), further comprising one or more alkali stimulants selected from silicates and a carbon-containing substance, and cured by the hydraulic property of the substance having latent hydraulic property. Agglomeration of material.

  (3) When agglomerating the metal-containing powdery waste, the metal-containing powdery waste, a substance having latent hydraulic property, and an oxide, hydroxide, carbonate, silicate, or alkali of an alkali metal are used. A metal-containing powder which is prepared by kneading at least one alkali stimulant selected from the group consisting of oxides, hydroxides, carbonates and silicates of earth metals with water and hardening the mixture. Agglomeration method of waste.

  (4) When agglomerating the metal-containing powdery waste, the metal-containing powdery waste, a substance having latent hydraulic property, and an oxide, hydroxide, carbonate, silicate, or alkali of an alkali metal are used. A metal-containing material comprising kneading a kneaded product of at least one alkali stimulant selected from the group consisting of oxides, hydroxides, carbonates and silicates of earth metals, a carbon-containing substance and water, and curing the mixture. Agglomeration method of powdery waste.

  (5) In the method for agglomerating metal-containing powdery waste according to (3), when the total amount of the metal-containing powdery waste and the substance having latent hydraulic property is 100 parts by mass, The amount of the substance having latent hydraulic property is 8 parts by mass or more, and the alkali stimulant is externally added by 0.4 parts by mass or more, and the water is externally added by 9 to 20 parts by mass and kneaded. A method for agglomerating metal-containing powdery waste, characterized in that it is made into a wrought product.

  (6) In the method for agglomerating metal-containing powdery waste according to (4), the total amount of the metal-containing powdery waste, the carbon-containing substance, and the substance having latent hydraulic property is set to 100 parts by mass. When the amount of the substance having latent hydraulic property is set to 8 parts by mass or more, the carbon-containing substance is set to 5 parts by mass or less, and the alkali stimulant is externally added by 0.4 parts by mass or more. And 9 to 20 parts by mass are added and kneaded to form a kneaded product.

  (7) In the method for agglomerating metal-containing powdery waste according to any one of the above (3) to (6), in preparing the kneaded material, the substance having latent hydraulicity and the alkali stimulant Are mixed to obtain a mixture, and the obtained metal-containing powdery waste and the water or further the carbon-containing substance are added to the obtained mixture and kneaded to prepare a kneaded product. How to agglomerate objects.

  (8) In the method for agglomerating metal-containing powdery waste according to any one of the above (3) to (7), the kneaded material is dried, coarsely pulverized, and left to stand. A method for agglomerating metal-containing powdery waste, which is pulverized into a lump having a particle size of 5 to 50 mm.

  (9) The agglomerate according to the above (1) or (2) is charged into the furnace from the furnace top of a shaft furnace having a carbon material packed bed therein, and A method for treating agglomerates of metal-containing powdery waste, comprising recovering a metal component as metal.

  ADVANTAGE OF THE INVENTION According to this invention, the metal-containing powdery waste can be agglomerated stably irrespective of climate, with good yield, with a predetermined quality, in a short period of time, and easily. The agglomerate produced by the present invention can be suitably used as a raw material to be charged from the top of a shaft furnace. In particular, the agglomerate obtained by adding a carbon-containing substance to the agglomerate is a shaft. Since phosphorus in the metal-containing powdery waste is vaporized and dephosphorized in the furnace, the transfer of phosphorus into the metal to be produced can be suppressed. By agglomerating and using together with the carbon-containing substance according to the present invention, it is possible to recover the metal component to the metal without transferring the phosphorus in the metal-containing powdery waste to the metal.

  In the present invention, the metal-containing powdery waste is agglomerated using the potential hydraulic property of a substance having potential hydraulic property. Materials having latent hydraulic properties include blast furnace slag. The substance having latent hydraulic properties has a slower hydration rate than the substance having hydraulic properties, and exhibits remarkable hydraulic properties particularly when mixed with an alkali stimulant. Therefore, by adding a metal-containing powdery waste and a substance having latent hydraulic properties together with an alkali stimulant and kneading it, it is possible to cure at a slower curing rate than a hydraulic substance such as Portland cement. Can be. For this reason, in the present invention, since the hardening progresses gradually, the agglomerate can be crushed with less power before the agglomerate develops the maximum strength, and can be easily crushed, so that fine powder is generated. Can be reduced, and the yield as a steelmaking raw material can be increased.

  Generally, when agglomerating a metal-containing powdery waste with a substance having latent hydraulic property, it takes about two weeks for the agglomerated product to harden to the maximum strength.

  On the other hand, when hardened with hydraulic Portland cement, it becomes a hard cured body in about one day, so not only strong power is required even if it is crushed on the next day of kneading, it is suitable as a raw material for iron making If a powder having a particle size of about 5 to 50 mm, which can be used for steelmaking, is to be obtained, a large amount of finer powder will be generated and the yield as a raw material for iron making will be reduced.

  In the case of using lump as a raw material for steelmaking, in the case of shaft furnaces such as blast furnaces and carbon material packed bed type smelting reduction furnaces, in addition to the strength necessary to prevent powdering during transport of raw materials, powdering when the raw materials fall in the furnace In order to suppress the occurrence to some extent, strength is required. Therefore, the blast furnace raw material requires a crushing strength of about 4 MPa or more, and a carbon material packed bed type smelting reduction furnace requires about 2 MPa or more. Further, in the case of use in a converter, it is not necessary to consider powdering in the furnace, so that it is sufficient that the crushing strength is about 1 MPa or more.

  The crushing strength and particle size of the agglomerate can be appropriately determined according to the application process of the agglomerate.

  In order to obtain a general iron-making raw material from a metal-containing powdery waste using the present invention, the crushing strength is set to about 4 MPa or more, based on the total amount of the metal-containing powdery waste and the substance having latent hydraulic property. The amount of the substance having latent hydraulic property is not less than 8% by mass, and the alkali stimulant is mixed with the external waste to be 0.4% by mass or more based on the total amount of the powdered metal-containing waste and the substance having latent hydraulic property. It is preferable that the mixture is kneaded while adding 9 to 20% by mass of water to the mixture with respect to the total amount of the metal-containing powdery waste and the substance having latent hydraulic property.

  When the amount of the substance having latent hydraulicity is 8% by mass or more with respect to the total amount of the metal-containing powdery waste and the substance having latent hydraulicity, the substance having latent hydraulicity is less than 8% by mass. In addition, it is difficult to sufficiently cure the entire metal-containing powdery waste, the crushing strength may not be 4 MPa or more, and the strength is not enough to crush to a size of about 5 to 50 mm that is easy to use as a raw material for ironmaking. This is because the generation of powder due to the heat increases and the yield decreases.

  Materials with latent hydraulic properties include blast furnace slag fine powder, etc., and increasing this amount does not prevent the hardening of metal-containing powdery waste, and this material itself is used as an agglomerate as a raw material for steelmaking. Since it can be usefully used as a slag-making material when used, it is not necessary to set an upper limit on the amount used, but if there is a lower limit on the amount of the metal component contained in the agglomerate, The upper limit of the substance having the potential hydraulic property may be determined so that the compounding amount of the metal component is compatible with the entire compound.

  Kneading by adding water in an amount of 9% by mass or more based on the total amount of the metal-containing powdery waste and the substance having latent hydraulic property is not sufficient if the amount of water is less than about 9% by mass. This is because a portion that does not agglomerate is formed, and powder having a low strength increases to lower the yield. On the other hand, if 20% by mass or more of water is added and kneaded, the strength after curing is reduced, and the crushing strength may not be 4 MPa or more.

  Some of the metal-containing powdery wastes are generated in a state of containing water, but in the present invention, in the case of indicating the composition, the mass of the remaining parts excluding the water is targeted.

  The reason that the alkali stimulant is 0.4% by mass or more based on the total amount of the metal-containing powdery waste and the substance having latent hydraulic property is that if the amount of the alkaline stimulant is less than this, the potential hydraulic potential is reduced. This is because it is insufficient to exhibit the potential hydraulic property of the substance having the following, the final strength is reduced, the pulverization at the time of crushing is increased, and the yield of the agglomerated product is reduced. In addition, even if it adds more than 4 mass% of an alkali stimulant, since the promotion effect of the latent hydraulicity by an alkali stimulant does not improve, it is better to make it the addition amount 4 mass% or less.

  Further, in the present invention, in preparing a kneaded product of metal-containing powdery waste, a substance having latent hydraulic properties, an alkali stimulant, and water, a substance having latent hydraulic properties and an alkali stimulant are used. It is preferable to prepare a kneaded product by mixing the metal-containing powdery waste and this mixture in advance and adding water while mixing the mixture. This is because the alkali stimulant generally has a lower density than metal-containing powdery wastes and substances having latent hydraulic properties, so even if these three types of powders are mixed simultaneously, it is difficult to mix them homogeneously. As a result, the mixing of the substance having the potential hydraulic property and the alkali stimulant tends to be insufficient, and as a result, the strength becomes uneven when the kneaded material is agglomerated, and 5 to 5 which is suitable as a raw material for ironmaking. This is because the yield of the agglomerated product of 50 mm decreases.

  In order to improve the yield of agglomerates, it is desirable that the kneaded material is dried and then coarsely pulverized and allowed to stand. Curing by the substance having latent hydraulic properties gradually progresses over a period of about two weeks, and the strength increases accordingly. Therefore, when the main pulverization is performed by a crusher or the like after the development of the strength up to a predetermined strength, for example, when the pulverization is performed to a size of 5 to 50 mm, which is a particle size range suitable for a steelmaking raw material, the power for the pulverization is large and the , And powder of 5 mm or less is generated, which lowers the yield.

  On the other hand, when the strength has not yet been sufficiently developed after drying the kneaded material, the material is coarsely pulverized, and a particle having a predetermined particle size of about 5 to 50 mm is prepared. If left untreated, agglomerates that require main grinding after strength development can be reduced. At this time, since the required strength has not yet been reached at the time of coarse pulverization, the power of a crusher or the like at the time of coarse pulverization is small, and it is not necessary to take time, so that the generation of powder of 5 mm or less can be reduced.

  Thus, the final yield of the agglomerated product of 5 to 50 mm can be improved by coarsely pulverizing after drying and before developing the strength. The timing of this coarse pulverization is preferably after drying and before the development of a predetermined strength. Specifically, when the development of the predetermined strength requires about two weeks after kneading, the timing is about three days to one week after kneading. It is desirable to do it in between. If coarse grinding is performed earlier than this, powder of 5 mm or less is likely to be generated due to insufficient drying or insufficient strength. When coarse crushing is performed after being left for more than one week, since the strength is high, the power of a crusher or the like for coarse crushing is increased, and the generation of powder during coarse crushing is increased. This is because the effect is reduced.

  Further, in the present invention, a carbon-containing substance may be added in preparing a kneaded product of metal-containing powdery waste, a substance having latent hydraulic properties, an alkali stimulant, and water. As the carbon-containing substance, a substance having a high carbon purity such as graphite may be used, or a substance containing 50% or more of a carbon content such as coal, coke, and blast furnace ash may be used. Organic substances such as resin waste can be used, but the particle size must be 1 mm or less in order to prevent agglomeration.

  When the carbon-containing substance is added, it is desirable that the carbon-containing substance is 5% by mass or less based on the total amount of the metal-containing powdery waste, the substance having latent hydraulic property, and the carbon-containing substance. This is because if the carbon-containing substance is added in excess of 5% by mass, the strength of the agglomerate produced by the curing of the substance having latent hydraulic properties will be weakened.

  Since the agglomerate produced in this way can be made into a high-strength agglomerate having a crushing strength of 4 MPa or more, it can be suitably used as a massive raw material charged from the top of a shaft furnace.

  Particularly in a carbon material-filled smelting reduction furnace, the shaft is heated to a high temperature of about 1000 to 1300 ° C. If there is carbon in the bulk material, phosphorus (phosphorus oxide) contained in the bulk material reacts with carbon. It is vaporized and dephosphorized and discharged from the furnace top along with the gas flow in the furnace. It is possible to separate the phosphorus in the agglomerate from the molten metal produced in the shaft furnace. For this reason, it is extremely preferable to add a carbon-containing substance to the agglomerate in advance, since the carbon of the agglomerate itself can reduce the phosphoric acid.

  In the present invention, as the substance having latent hydraulic properties, for example, blast furnace slag fine powder having a particle diameter as shown in Table 2 manufactured by pulverizing blast furnace slag can be used, and a substance having latent hydraulic properties can be used. It is preferable to use blast furnace slag fine powder because it is easy to handle and easily available. As the alkali stimulant, one or more selected from alkali metal oxides, hydroxides, carbonates, silicates, alkaline earth metal oxides, hydroxides, carbonates, and silicates may be used. it can. For example, various substances such as slaked lime, quicklime, calcium carbonate, calcium silicate, potassium hydroxide, potassium carbonate and the like can be used. In particular, it is preferable to use slaked lime as an alkali stimulant because it is easy to handle, easily available, and inexpensive.

  [Example 1] Steelmaking dust containing metals having the compositions shown in Table 1 was used as the metal-containing powdery waste to be agglomerated.

  Fine blast furnace slag powder as a substance having a potential hydraulic property and slaked lime as an alkali stimulant were mixed with this. The proportion of the blast furnace slag fine powder was changed from 5 to 50% by mass based on the total amount of the steelmaking dust and the blast furnace slag fine powder. For slaked lime, 5% by mass is added to the mixture of steelmaking dust and the substance having latent hydraulicity, and for moisture, the mixture is added to the mixture of steelmaking dust and the substance having latent hydraulicity. And was fixed at 15% by mass.

  Water was added to a mixture of the steelmaking dust, the blast furnace slag fine powder, and the alkali stimulant, followed by kneading. After that, it is put in a mold and dried, and then coarsely pulverized one week later, further dried for one week, and then pulverized by a crusher, and the crushing strength and agglomeration of the agglomerate (size: 5 to 50 mm) The yield of the product (size; 5 to 50 mm) was measured.

  The target strength of the agglomerated product is 4.0MPa or more in crushing strength obtained by the following measurement as the crushing strength that does not powder when using the agglomerated product. The target yield of 50 mm) was 60% or more in terms of the size after classification; the weight calculated from the weight of the agglomerated product of 5 to 50 mm / the total weight sieved.

  When the crushing strength passes through a 50 mm sieve in the agglomeration product and selects any 20 lumps as a representative sample from the lumps remaining on the 20 mm mesh sieve, when this is pressed down with a press machine, The maximum load before breaking was measured, and the arithmetic average of 18 data excluding the maximum and minimum values of the 20 data was obtained, and this was defined as the crushing strength.

  The crushing strength of the agglomerated product (size: 5 to 50 mm) determined above is shown in FIG. 1, and the yield of the agglomerated product (size: 5 to 50 mm) is shown in FIG.

  From FIG. 1 and FIG. 2, the target crushing strength and target yield of the agglomerated product (size: 5 to 50 mm) can be achieved if the ratio of the blast furnace slag fine powder as the substance having latent hydraulic property is set to 8% by mass or more. Was confirmed.

  Since the target strength of the agglomerate can be appropriately selected depending on the place where it is used, for example, when used in a converter, the amount of the blast furnace slag fine powder can be adjusted by setting the target strength at about 1 MPa.

  [Example 2] Next, in order to investigate an appropriate range of moisture, steelmaking dust having the same composition as in Example 1 was used as a metal-containing powdery waste to be agglomerated. Blast furnace slag fine powder was mixed.

  The proportion of the blast furnace slag fine powder was 8% by mass based on the total amount of the steelmaking dust and the blast furnace slag fine powder. Also, slaked lime was adjusted to 0.4% by mass with respect to a mixture of steelmaking dust and a substance having latent hydraulicity, while moisture was adjusted with respect to a mixture of steelmaking dust and a substance having latent hydraulicity. The crushing strength of the agglomerated product and the yield of the agglomerated product were measured in the same manner as in Example 1 while changing the range of 5 to 30% by mass.

  The results are shown in FIGS.

  From FIGS. 3 and 4, the water is added to the mixture of the steelmaking dust and the substance having the potential hydraulic property by 9 to 20% by mass, and the crushing strength of the target agglomerated product and It has been found that both agglomerate yields can be achieved.

  In addition, the crushing strength of the agglomerated product increases as the moisture ratio decreases, but the yield of the agglomerated product decreases. The reason for this is that, for those agglomerated to a size of 5 to 50 mm, the lower the moisture value, the stronger the strength.However, as the water content decreases, the kneading becomes insufficient and there is a portion that does not agglomerate. It is considered that the ratio of agglomeration to 5 to 50 mm decreases.

  Example 3 A method of agglomerating steelmaking dust capable of further improving the yield was confirmed. Steelmaking dust was used as metal-containing powdery waste, blast furnace slag fine powder was used as a substance having latent hydraulic properties, and slaked lime was used as an alkali stimulant. Their composition is almost the same as in Example 1, the ratio of the blast furnace slag fine powder is 8% by mass with respect to the total amount of the steelmaking dust and the blast furnace slag fine powder, and the moisture has the steelmaking dust and the potential hydraulic property. It was constant at 15% by weight, based on the mixture with the substance.

  The method of mixing blast furnace slag fine powder and slaked lime in advance and mixing this with steelmaking dust was performed with pre-kneading, and the method of Examples 1 and 2 was performed without pre-kneading, and agglomerated in the same manner as in Examples 1 and 2. The crushing strength of the product and the yield of the agglomerated product were determined, and the results are shown in Table 3. Table 2 shows the particle diameter and bulk density of steelmaking dust, blast furnace slag fine powder and slaked lime.

  From the results shown in Table 3, there was no significant difference in the crushing strength of the agglomerated product when pre-kneading was performed as compared with the case without pre-kneading, but the yield of the agglomerated product was 7%. It has been confirmed that it has improved.

  When kneading substances having a difference in particle size and density, rather than mixing and kneading at the same time, by mixing blast furnace slag fine powder and slaked lime in advance, mixing and kneading with steelmaking dust, It can be seen that the yield of agglomerated products is significantly improved.

  Example 4 An agglomerate was produced using plating sludge as metal-containing powdery waste. The plating sludge has the composition shown in Table 4. In addition, although the composition of Table 4 is shown by the mass% of a dry base, the oil content is contained 0.05% by mass on the outside. In addition, it is generated in a state containing moisture. In this example, the water content was 10% by mass.

  Fine powder of blast furnace slag as a substance having latent hydraulic properties and slaked lime as an alkali stimulant were added to the plating sludge (Example 4-1). In addition, blending was carried out in which a part of the plating sludge was replaced with coke powder (Example 4-2), and water was added thereto and kneaded to form agglomerates. The respective formulations are shown in Table 5. The water content was adjusted to 20% by mass in the state of the kneaded material, based on the total amount of the solid content of the plating sludge and the blast furnace slag fine powder, or the solid content obtained by adding coke powder thereto.

  This kneaded material is put into a mold and dried for one week, then coarsely pulverized and further dried for one week, and then crushed with a crusher, sieved, and the yield of agglomerated products of 5 to 50 mm is obtained. In addition to the measurement, the crushing strength of the agglomerated product was examined. In addition, a part of each of the blends was fully pulverized two weeks later without coarse pulverization, and the yield was measured.

  The yield of the agglomerated product is sieved in two stages of 50 mm and 5 mm openings of the agglomerated product after the main pulverization, and what has remained on the 5 mm sieve through the 50 mm sieve is defined as the agglomerated product. The value obtained by dividing the mass of the agglomerated product by the mass of all agglomerated products obtained by sieving is obtained in%. The target for yield was 60%. The crushing strength of the agglomerated product was determined by further sieving the agglomerated product with a mesh of 20 mm, selecting 20 agglomerates from the agglomerated product on this sieve as a representative sample, and rolling it down with a press. The maximum load to failure was measured, and the arithmetic average of 18 data excluding the maximum and minimum values among the data of the 20 samples was obtained to obtain the crushing strength.

  Table 6 shows the yield and crushing strength of the agglomerated product thus determined, and Table 7 shows the chemical composition. In all cases of Examples 4-1 and 4-2, the yield of the agglomerated product exceeds 60%, which indicates that it is suitable as an agglomeration method. In addition, since the crushing strength was 4 MPa or more, it was found that there was no problem in using them as furnace top charging materials for a shaft furnace. Further, the yield was improved by about 4% in the coarsely pulverized product.

  The agglomerates according to Examples 4-1 and 4-2 were used in a carbon material packed bed type smelting reduction furnace schematically shown in FIG. Tables 8 and 9 show the specifications and operating conditions of the carbon material packed bed type smelting reduction furnace 1. The blowing raw material is obtained by adding limestone as a slag-making material to a powdered raw material obtained by drying steelmaking dust (represented in Table 1) generated by stainless steel refining. The agglomerated products according to Examples 4-1 and 4-2 were charged into the carbon material packed bed type smelting reduction furnace 1 together with coke from the furnace top.

  After the agglomerated product of Example 4-1 was charged from the furnace top and operated for 10 days, the agglomerated product was changed to that shown in Example 4-2 and operated for 10 days. As a result, the operation itself of the carbon material packed bed type smelting reduction furnace 1 could be continued without any particular problem. FIG. 6 shows the change in the phosphorus concentration in the metal produced in this operation. As shown in FIG. 6, the agglomeration product of Example 4-2 was compared with the time when the agglomeration product of Example 4-1 was used. The concentration of phosphorus in the produced metal was lower when the metal was used.

  This is because, in the agglomerated product of Example 4-2, since coagulated powder was added to the agglomerated product, the sludge was formed in a mixed state of plating sludge and coke powder. While the shaft of the smelting reduction furnace 1 is exposed to a high temperature of about 1000 to 1300 ° C., the phosphorus in the plating sludge and the carbon in the coke powder come into direct contact with each other to reduce phosphorus. It is considered that the gas was vaporized and moved into the exhaust gas of the smelting reduction furnace 1 together with the furnace gas.

  As described above, the agglomerates of the metal-containing powdery waste, the carbon-containing substance, the substance having latent hydraulic properties, and the metal-containing powdery waste obtained by curing the alkali stimulant are used as in the carbon material packed bed type smelting reduction furnace 1. Phosphorus in metal-containing powdery waste is vaporized and dephosphorized by carbon in carbon-containing material by charging the shaft furnace at the top, reducing the phosphorus concentration in the metal produced in the shaft furnace There is an advantage that can be.

It is the graph which showed the effect on the crushing strength of the agglomerate when blast furnace slag powder was used as a substance having latent hydraulic properties. It is the graph which showed the effect on the yield of agglomerate when blast furnace slag powder was used as a substance having latent hydraulic properties. 4 is a graph showing the relationship between the crushing strength of the agglomerated product and the water addition rate when blast furnace slag powder is used as a substance having latent hydraulic properties. 4 is a graph showing the relationship between the yield of agglomerated products and the water addition rate when blast furnace slag powder is used as a substance having latent hydraulic properties. It is an arrangement view showing an outline of a carbon material packed bed type smelting reduction furnace. 4 is a graph showing a transition of a phosphorus concentration in a metal.

Explanation of reference numerals

REFERENCE SIGNS LIST 1 carbon material packed bed type smelting reduction furnace 2 solid reducing material 3 upper tuyere 4 lower tuyere 5 blower 6 hot air generator 7 raw material blowing device 8 furnace top charging device 9 taphole

Claims (9)

  Select from metal-containing powdery waste and substances with latent hydraulic properties, and alkali metal oxides, hydroxides, carbonates, silicates, alkaline earth metal oxides, hydroxides, carbonates, and silicates An agglomerate of metal-containing powdery waste, comprising one or more alkali stimulants obtained and hardened by hydraulic property of the substance having latent hydraulic property.   From metal-containing powdery waste, substances with latent hydraulic properties, and alkali metal oxides, hydroxides, carbonates, silicates, alkaline earth metal oxides, hydroxides, carbonates, and silicates The lump of metal-containing powdery waste according to claim 1, further comprising one or more selected alkali stimulants and a carbon-containing substance, and hardened by hydraulicity of the substance having latent hydraulicity. Immobilization.   When agglomerating the metal-containing powdery waste, the metal-containing powdery waste, a substance having latent hydraulic property, and an oxide, hydroxide, carbonate, silicate, or alkaline earth metal of an alkali metal A metal-containing powdery waste, characterized in that a kneaded product of water and at least one alkali stimulant selected from oxides, hydroxides, carbonates and silicates is prepared and hardened. Agglomeration method.   When agglomerating the metal-containing powdery waste, the metal-containing powdery waste, a substance having latent hydraulic property, and an oxide, hydroxide, carbonate, silicate, or alkaline earth metal of an alkali metal Metal-containing powdery waste, comprising kneading a mixture of at least one alkali stimulant selected from the group consisting of oxides, hydroxides, carbonates and silicates with a carbon-containing substance and water, and curing the mixture. How to agglomerate objects.   The method for agglomerating metal-containing powdery waste according to claim 3, wherein when the total amount of the metal-containing powdery waste and the substance having latent hydraulic property is set to 100 parts by mass, latent water therein is contained. The amount of the substance having hardness is 8 parts by mass or more, and the alkali stimulant is externally added at 0.4 parts by mass or more, and the water is externally added at 9 to 20 parts by mass and kneaded to obtain a kneaded material. A method for agglomerating metal-containing powdery waste, comprising:   In the agglomeration method of metal-containing powdery waste according to claim 4, when the total amount of the metal-containing powdery waste, the carbon-containing substance, and the substance having latent hydraulic property is 100 parts by mass, Among them, the amount of the substance having latent hydraulic property is set to 8 parts by mass or more, the carbon-containing substance is set to 5 parts by mass or less, and the alkali stimulant is externally added by 0.4 parts by mass or more, and the water is externally added. A method for agglomerating metal-containing powdery waste, comprising adding 9 to 20 parts by mass and kneading to obtain a kneaded product.   The method for agglomerating metal-containing powdery waste according to any one of claims 3 to 6, wherein, in preparing the kneaded material, the latent hydraulic material and the alkali stimulant are mixed to form a mixture. Agglomerating a metal-containing powdery waste, wherein the obtained mixture is mixed with the metal-containing powdery waste and the water or further the carbon-containing substance and kneaded to prepare a kneaded product. .   The method for agglomerating metal-containing powdery waste according to any one of claims 3 to 7, wherein the kneaded material is dried, then coarsely pulverized and left, and after the strength is developed, the final pulverization is performed. A method for agglomerating metal-containing powdery waste, characterized in that the agglomeration has a particle size of:   3) charging the agglomerate according to claim 1 or 2 from the top of a shaft furnace having a packed bed of carbon material therein, and recovering a metal component in the metal-containing powdery waste as metal. A method for treating agglomerates in metal-containing powdery waste.

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