KR101475125B1 - Unfired carbon-containing agglomerate for blast furnaces and production method therefor - Google Patents

Abstract

This is a non-compacted plastic hamtan light, the carbon content (TC) is 18 to 25 mass% and, CaO content (mass%) and SiO ₂ content ratio CaO / SiO ₂ is 1.0 to 2.0 (% by weight). The method for producing the non-sintered hammerized compacted light includes the steps of: forming a formed body by mixing and kneading a raw material for a ham, a hammer and a binder, and kneading the mixture to form a molded body; having a gain step, the unfired hamtan compacted light carbon content (TC) is 18 to 25 mass%, and gangue components of the CaO content (mass%) and SiO ₂ content (mass%) ratio CaO / SiO ₂ is from 1.0 to 2.0, the mixing condition of at least one selected from the group consisting of the ore item and the binder amount is adjusted in the forming step of the molded article.

Description

Technical Field [0001] The present invention relates to a non-calcined hamstick fiber for blast furnace and a method for producing the same,

The present invention relates to a non-calcined hamstick compact light for a blast furnace, and more particularly to a non-burned compact hamstick compact which can lower the melting cost of the furnace by lowering the furnace slag melting point of the furnace.

The present application claims priority based on Japanese Patent Application No. 2009-191966 filed on August 21, 2009, the contents of which are incorporated herein by reference.

Conventionally, various types of quartz dust or hammer dust recovered from various dust collectors of steel mills are blended and a cement-based hydraulic binder is added and kneaded and molded to produce non-burned compacted light having a diameter of 8 to 16 mm, .

As a method for producing non-calcined hamsters compacted light, there is known a method in which iron-based dust is granulated with pellets, followed by curing and curing the pellets. In the step of assembling the iron-based dust with pellets, the particle size distribution of the dust is adjusted to an appropriate range, a binder such as burnt lime, cement and the like and water of 5 to 15% are added, and the mixture is assembled by a disk pelletizer, .

In order to reduce the reducing cost in the blast furnace operation, it is required to increase the carbon content (T.C) of the non-calcined hamlet compacted light in the production of such non-calcined hamstick compacted light.

For example, in Patent Document 1, a carbon-based non-burned compacted light is produced by blending a raw material for iron oxide and a carbon-based carbonaceous material, adding a binder, kneading, molding and curing. This carbon-containing, non-sintered compacted light has carbon of 80 to 120% of the theoretical amount of carbon necessary for reducing iron oxide contained in the iron oxide raw material to metal iron. Further, the binder is selected so that the crush strength at normal temperature is 7850 kN / m < 2 > or more, and mixing, molding, and curing are performed. Since the reduction reaction is caused by the carbon in which the iron oxide is contained in the non-calcined hamsters compacted light, the reduction ratio can be improved.

However, in this production method, the carbon content is limited in order to secure strength, and the effect of reducing the reduction ratio in a sufficient furnace is not obtained. In order to sufficiently obtain the effect of reducing the reduction ratio, when the non-calcined hamstick intense light is used in a large amount in the blast furnace, the amount of heat absorbed by the dehydration reaction of the binder in the blast furnace is increased. This has the disadvantage of forming a low-temperature heat-storage zone and promoting reduction and differentiation of the sintered ores.

In addition, since calcium oxide and CaO-based cement are frequently used as the binder, the content of CaO in the non-calcined hamlet compacted light becomes high. As a result, the viscosity of the melt (melt) generated from the non-calcined hamsters in the course of the reaction becomes excessively high. This inhibits coagulation and burn through of the generated metal. As a result, there has been a disadvantage that the ventilation and lyophobicity of the furnace in the furnace deteriorates.

For example, when the non-calcined hamstick compact light is melted and dropped at a low temperature, the non-calcined hamstick compact light is melted at an early stage in the vertical furnace, and the gap of the raw material filled in the furnace easily flows down. In this case, the period of contact with the coke becomes long. As a result, it is possible to accelerate the reduction reaction of the powdered iron ores and the carburization reaction of the produced iron in the non-calcined hamstorm compact.

In Patent Document 2, attention has been paid to the fact that even in the case of powdered iron ores where surface enrichment of SiO ₂ or Al ₂ O ₃ has occurred, the melting temperature can be reduced by coating CaCO ₃ . Based on this point of view, a non-calcined hamstick compact is proposed in which fired iron ore and flux are combined through coal.

Further, in Patent Document 2, although the carbon black compact containing 23.3 to 24.6 mass% of coal is disclosed, the carbon content of coal is generally about 70%, and the remainder is ash and volatile content. Therefore, the carbon content in the hammerite compact is equivalent to 16 to 17 mass%.

On the other hand, many reports have been made about the relationship between the dropping load and the components of the sintered ores.

For example, in Non-Patent Document 1, when the dropwise addition the temperature of the sintered ore is increased to which is changed in a non-linear, is the dropping temperature lower CaO / SiO ₂ = the vicinity of 1.0, and MgO relative to CaO / SiO ₂ is added dropwise temperature Has been reported.

In addition, in Non-Patent Document 2, it has been reported that when 2% of MgO is added to a dust cold pellet (cement bonded) containing 7% of carbon, the aeration resistance at high temperature is lowered.

As described above, in order to improve the metal loadability of the sintered ores and dust pellets having a carbon content of less than 10%, it is well known that the gangue composition of CaO / SiO ₂ and MgO is optimized. However, the proper conditions of the metal loading property of the carbon black compact having a completely different carbon content (18 to 25 mass%) completely different from the reducing behavior and the slag melting point at the bottom of the furnace for determining the metal loading property have not been known so far .

Accordingly, the inventors have found that a carbon-rich, high-carbon (total C content 20%, total Fe content 40%, CaO 11%, SiO 6%, Al ₂ O ₃ 2.5%, MgO 0.5%) were investigated. 8 is a graph showing the results of a conventional sintered light (total Fe content 58.5%, FeO 8%, CaO 10%, SiO ₂ 5%, Al ₂ O ₃ 1.7%, MgO 1.0%), and the relation between the temperature and the reduction ratio for a large amount of carbon-rich sand blasted light. Referring to FIG. 8, it can be seen that, in comparison with the conventional sintered ores, the reduction progresses remarkably in the low-temperature region. This is a major feature of the carbonaceous compact having a high carbon content.

Next, the change of the slag melting point (CaO-SiO ₂ -Al ₂ O ₃ -MgO-FeO) by the reduction process was simulated by a computer using the reduction ratio of FIG. 8 obtained from the result of the above reduction test. Also, assuming that the irreducible iron among the iron components of the sintered or hardened light is present as FeO, the slag melting point was calculated from the reduction ratio. The results are shown in Fig. Here, the melting point means a temperature at which all the liquid phase is obtained, and a melt is generated even at a melting point or lower. However, when the melting point is high, since the amount of the melt is low, the melting point indirectly indicates the amount of melt.

9, in the sintered ores, it is considered that the slag melting point coincides with the sample temperature at 1200 to 1400 ° C, and a large amount of melt is generated in this temperature range. On the other hand, the slag melting point of the blast furnace tonal light remarkably rises from around 900 ° C and reaches 1600 ° C or more. Therefore, it is considered that the reduction proceeds in a state in which the amount of the melt is very small in the carbonaceous intense light having a high carbon content. As a result, the solid phase is always present, so that the agglomeration of the metal is inhibited, which causes the droplet deterioration. In the above-mentioned five-component system (CaO-SiO ₂ -Al ₂ O ₃ -MgO-FeO), the effect of FeO on the melting point is very large in the carbonaceous compact having a high carbon content, and the reduction proceeds rapidly at a low temperature. The result shown in Fig. 9 is a phenomenon specific to the carbon-rich light having a high carbon content.

As described above, the reduction of the carbonaceous compact having a high carbon content progresses significantly in the low temperature region as compared with the sintered compact, and the reduction proceeds in a state where the amount of the melt is very small. As a result, the knowledge of the loading characteristics in the progress of the reduction of the sintered ores can not be directly applied to the carbon-rich compact having a high carbon content.

When the blast furnace light is used in the blast furnace, when the melting point of the slag is high, the lower surface of the fusion bond is lowered, the lower fill zone is narrowed, and the slag intensity of the filler and core is increased. Specifically, the molten liquid remains in the gap (flow path) because the flow of the melt is not smooth in the enemy base and the core portion (zone where the metal and slag flow down to the well portion while separating the specific gravity). As a result, the flow of gas drifts, and uniform gas heating can not be performed. As a result, locally heat-deficient portions are generated, making it difficult to operate the furnace with low air permeability.

Japanese Patent Application Laid-Open No. 2003-342646 Japanese Patent Application Laid-Open No. 2005-325412

ISIJ International 44 (2004), p. 2057 Iron and Steel, 70 (1984), p. S825

In the present invention, the component condition of the hammerized amorphous light having the slag melting point optimum for blast furnace use is specified. Based on the results of this study, it is an object of the present invention to provide a non-calcined hamlet compacted light which can reduce the melting cost of the blast furnace by lowering the melting point of the slag and a method for producing the same.

The inventors of the present invention have found that by setting the CaO / SiO ₂ of the gangue component of the sand blasted light to a specific range (1.0 to 2.0), it is possible to reduce the furnace slag melting point and achieve the excellent metal drop- . It has been found that it is preferable to adjust the blending amount of the ore containing the high SiO ₂ and the MgO-containing subsidiary material as described later in order to adjust the CaO / SiO ₂ of the gangue component of the non-calcined hamsters compacted to 1.0 to 2.0.

The unfired hammer intruding light for a blast furnace according to one embodiment of the present invention is obtained by mixing and kneading a raw material for a steel and a raw material for a hammer and a binder and kneading the mixture to obtain a molded body and subsequently curing the molded body, a content (TC) is 18 to 25 mass%, and the non-CaO / SiO ₂ is 1.0 to 2.0 of CaO content (mass%) and SiO ₂ content (mass%) of gangue components.

The unfired hamtan compacted light for blast furnace according to one embodiment of the present invention, CaO content (% by weight), SiO ₂ content (mass%), Al ₂ O ₃ content (% by weight), MgO content (mass%) and carbon content (TC) gangue amount represented by (% by weight) and _{[(CaO + SiO 2 + Al} 2 O 3 + MgO) / (100- carbon content (TC))], the value of 0.25 or less, and MgO content is 0.5 mass% or more .

The content of the binder may be 5 to 10% by mass.

The method for producing non-calcined hamsters compacted light for a blast furnace according to one embodiment of the present invention is characterized by comprising a step of forming a compact to obtain a compact by mixing and kneading a raw material for ham and a raw material for ham and a binder and a binder, and a curing unfired hamtan has a step for obtaining a compacted light, the unfired hamtan compacted light carbon content (TC) is 18 to 25 mass%, and the CaO content (% by mass) of the gangue component and SiO ₂ content (mass%) Of CaO / SiO ₂ is 1.0 to 2.0 in the step of forming the molded article, the mixing condition of at least one selected from the group consisting of the ore item and the binder amount is adjusted.

(% By mass), SiO ₂ content (% by mass), Al ₂ O ₃ content (% by mass), and Al ₂ O ₃ content (mass%) of the non-calcined hamlet compacted light for a blast furnace relating to an embodiment of the present invention, and MgO content (mass%) and carbon content (TC) gangue amount represented by (% by weight), the value of _{[(CaO + SiO 2 + Al} 2 O 3 + MgO) / (100- carbon content (TC))] 0.25 or less, The mixing conditions may be adjusted in the step of forming the molded product so that the MgO content is 0.5% by mass or more.

The amount of the binder may be adjusted in the range of 5 to 10% by mass.

In the step of forming the compact, one or both of an additive selected from zircon, zircon, dolomite, dolomite, nickel slag, magnesite and brucite and orite containing high SiO ₂ is further blended, and carbon of the non- content (TC) so as to be 18 to 25 mass%, and the CaO content and SiO ₂ content ratio of CaO / SiO ₂ is 1.0 to 2.0, and the additives may be adjusted and the amount of SiO ₂ containing ore.

The non-calcined hamlet compacted light for a blast furnace according to one embodiment of the present invention has a sufficient carbon content to improve the reduction ratio of the main iron-containing blast furnace raw materials such as sintered oresite as well as non-calcined hamlet compacted light. Further, in the blast furnace operation, the melting point of the slag can be suppressed to be lower than that of the conventional art, and excellent reduction generating slag characteristics (metal dropping property) can be achieved.

Therefore, when the non-calcined hamstick compacted light according to one embodiment of the present invention is used as a part of the iron-containing raw material for blast furnace, good air permeability can be realized in the furnace under the blast furnace operation. In addition, reduction ratio (coke ratio) can be greatly reduced.

In the method for producing non-calcined hamstick compacted light for a blast furnace according to one embodiment of the present invention, since the non-sintering process is applied, energy saving and lowering of CO ₂ can be achieved compared with a sintering process. Further, the dust generated in the iron-making process can be recycled as the iron-containing raw material and the carbonaceous material by a relatively inexpensive and simple method.

1 is a graph showing the relationship between the amount of binder (cement) (and the ratio of CaO / SiO ₂ ) and the cold-pressing strength.
Fig. 2 is a graph showing the relationship between CaO / SiO ₂ and slag melting point of sintered light and non-sintered sand blasted light in the case where the MgO content is 1.5%.
3 is a graph showing the relationship between the MgO content and the slag melting point of sintered light and non-sintered Hamming compacted light when CaO / SiO ₂ is 1.5.
FIG. 4 is a graph showing the relationship between CaO / SiO ₂ and the metal loading rate of non-calcined hamsters compacted light and sintered ores.
5 is a graph showing the relationship between the MgO content and the metal loading rate of non-calcined hamsters compacted light and sintered ores.
Figure 6 is a view showing the relationship between the value and the metal loading rate of gangue amount _{(CaO + SiO 2 + MgO +} Al 2 O 3) / (100-TC).
7 is a graph showing the relationship between the carbon content (TC) and the metal loading rate of the non-calcined hamlet compacted light.
FIG. 8 is a graph showing the relationship between the temperature and the reduction rate of the conventional sintered light and the non-sintered hammer tendon light having a high carbon content.
9 is a graph showing the relationship between the temperature of a conventional sintered light and the non-sintered hammer tendon light having a high carbon content and the calculated value of the slag melting point.

The non-calcined hamlet compacted light for a blast furnace of the present embodiment is produced by mixing and kneading a raw material for a steel ham, a raw material for a hammer and a binder, molding the kneaded material to obtain a molded body, and subsequently curing the molded body. Carbon content (TC) is 18 to 25% by weight and the gangue components CaO / SiO ₂ is 1.0 to 2.0. As a result, a slag melting point optimum for blast furnace use is obtained.

In the present embodiment, the carbon content (T.C) of the non-calcined hamlet compacted light is 18 to 25 mass%, preferably 20 to 23 mass%.

When the carbon content is less than 18%, even if the gangue component is adjusted, the effect of reducing the reduction ratio is reduced. When the carbon content exceeds 25 mass%, it is used for blast furnace, so that it is impossible to obtain the minimum necessary cold brittleness strength.

The ratio CaO / SiO ₂ (also referred to as basicity) of the CaO content (mass%) and the SiO ₂ content (mass%) of the gangue component of the non-calcined hamsters compacted light is 1.0 to 2.0, and preferably 1.4 to 1.7.

By setting CaO / SiO ₂ to a low value in the range of 1.0 to 2.0, the metal loading rate can be improved. When CaO / SiO ₂ exceeds 2.0, the metal loading rate becomes less than 50%. When the CaO / SiO ₂ is less than 1.0, the effect of improving the metal loading rate is saturated.

In the present embodiment, the value of the gangue content is preferably 0.25 or less, and more preferably 0.22 to 0.25. Here, the gangue amount is a value calculated by the following equation.

Gangue amount _{= (CaO + SiO 2 + Al} 2 O 3 + MgO) / (100- carbon content (TC))

In addition, expression of CaO, SiO _2, Al ₂ O ₃ and MgO, each unfired hamtan compacted light of the CaO content (% by weight), SiO ₂ content (mass%), Al ₂ O ₃ content (% by mass), and MgO content (mass%).

By setting the value of the gangue content to 0.25 or less, the amount of slag can be reduced and the dropping property can be further improved.

The MgO content is preferably 0.5% by mass or more, and more preferably 0.6 to 2.0% by mass. As a result, the melting point of the low FeO slag (slag having a small FeO content) is lowered by MgO, and the metal dropping property can be further improved.

The method for producing non-calcined ham to be mixed light for a blast furnace of the present embodiment is a method for producing a blast furnace raw material for a blast furnace, comprising the steps of: forming a formed body by mixing and kneading a ham steel raw material and a binder, And a step of obtaining non-calcined hamsters compacted light. In the process of forming the formed body, unfired hamtan compacted light carbon content (TC) is by 18 to 25 mass%, and the ratio CaO / SiO ₂ of the CaO content (mass%) and SiO ₂ content (mass%) of the gangue component 1.0 to 2.0, the mixing condition of at least one selected from the group consisting of the ore item and the binder blend amount is adjusted.

Examples of the iron-based raw material used in the present embodiment include sintered dust generated in a steelmaking process, iron oxide dusts such as blast furnace dust, pellet feeds having a smaller particle size than sintering powder iron ores, and sintered powdered iron ores Fine iron ore, and the like.

Depending on the ore items used, iron and SiO ₂ The content of the gangue component is greatly different. Therefore, by selecting the ore item to be used, the CaO / SiO ₂ value can be adjusted. In particular, the CaO / SiO ₂ value greatly influences the amount of the ore having a large SiO ₂ content.

Examples of the ore items used in the present embodiment include India Haishirashasu, Lob River, Yan Dukuza, Rio de Seas (Itabira), Mara Mamba, and the like.

Examples of raw materials for use in the present invention include first ash, coke dust, differential coke, and anthracite.

Examples of the binder to be used in the present embodiment include an aging binder consisting of a fine powder or an alkali stimulant mainly comprising blast furnace slag which is generally used, quicklime, portland cement, bentonite and the like. The amount of the binder (amount added) may be appropriately determined in consideration of other blending conditions and the like. When the blending amount of the binder is too small, it becomes difficult to sufficiently maintain the cold rolling strength of the non-sintered ham shot compacted light. If the blending amount of the binder is too large, the amount of slag of the non-calcined hamlet compacted light increases, and the air permeability in the furnace bottom becomes unstable. As a result, a stable reductive reduction effect can not be obtained.

Therefore, the cold hardness of the non-calcined hamsters compacted in which CaO / SiO ₂ was changed by adjusting the amount of the binder was investigated. The obtained results are shown in Table 1 and Fig.

The amount of binder (cement) blended (CaO / SiO ₂ decreased) and the cold strength decreased. And, when CaO / SiO ₂ is less than 1.0 (the amount of the binder (cement) is less than 5% by mass), it is difficult to maintain the cold crushing strength of 100 kg / cm 2. When the cold-crushing strength of the non-calcined hamstick compacted light is less than 100 kg / cm 2, there is a case where the non-calcined hamstick compacted light is caused to be transported to the blast furnace and to be differentiated when charged. In order to maintain the crushing strength of the cold at 100 kg / cm 2 or more, it is preferable that the amount of the binder (cement) is 5 mass% or more. If the amount of the binder (cement) is more than 10% by mass, the amount of gangue may increase. For this reason, it is preferable that the blending amount of the binder (cement) is 10 mass% or less. Therefore, the blending amount of the binder is preferably 5 to 10% by mass.

In addition, free water is introduced into the hydrate in the compacted sand by the hydration reaction of the cement during curing in the process of mixing, kneading, molding and curing. Therefore, when the raw material is subjected to the production process, the total amount of the raw material is slightly changed, but the amount of change is small, and it may be considered that there is almost no change. As a result, for example, the blending amount of the binder becomes substantially equal to the binder content in the produced non-calcined hammer intruding light. The amount of the other components in the manufacturing process is almost the same as that in the non-calcined ham denatural light.

Therefore, the content of the binder in the non-calcined hamstick compact light of the present embodiment is preferably 5 to 10% by mass, so that the cold-pressing strength of 100 kg / cm 2 or more can be achieved as described above.

In the present embodiment, it is more preferable to mix the subsidiary raw material and the ore containing high SiO ₂ . Thereby, the component adjustment can be performed more strictly. In particular, the CaO / SiO ₂ value can be adjusted without depending on the amount of the binder.

Examples of the additive material include silica based on SiO ₂ , serpentine based on MgO, olive rock, dolomite, nickel slag, magnesite and brucite. The high SiO ₂ -containing ore is an ore having a SiO ₂ content of 3.5 mass% or more.

Generally, when the chemical composition of the target non-calcined ham denitration light is specified, the amount of these additives and the amount of the high SiO ₂ -containing ore is automatically determined. Therefore, the amount of these additives and the amount of the high SiO ₂ -containing ore to be blended is not particularly limited and is appropriately determined according to the chemical composition of the non-calcined hamsters.

Next, the method of adjusting CaO / SiO ₂ , MgO content and gangue content will be described in more detail.

CaO / SiO ₂ is determined according to the amount of CaO and the amount of SiO ₂ contained in the raw material to be blended.

CaO is mainly contained in a binder, a blast furnace primary used as a raw material for a hammer, a sintered dust used as a raw material for iron and a converter dust, and the CaO content can be adjusted by suitably adjusting the blending amount thereof have. However, in the case of using the cement binder CaO minutes high as the binder, CaO / SiO ₂ is adjusted to the CaO content to be 1.0 to 2.0, it is necessary to reduce the amount of the binder itself. Therefore, it is necessary to consider whether or not sufficient cold-bracing strength can be obtained.

SiO ₂ , and MgO are mainly included in the binder, the first blast furnace used as a raw material for the hammer, the sintering dust used as the raw material for the iron, and the ash in the carbonaceous reduction.

In this embodiment, when a non-compacted plastic hamtan light of CaO / SiO ₂ is 1.0 to 2.0, regardless of the addition in the form of SiO ₂ (in the form of raw material including SiO _2), it can result in a certain effect. Also, with respect to MgO, when the MgO content is 0.5 mass% or more, a certain effect can be obtained irrespective of the addition form of MgO (the form of the raw material including MgO).

In the case where the value of CaO / SiO ₂ is actively reduced or the MgO content is set to 0.5% by mass or more, additives such as silica, serpentinite, olam rock, dolomite, nickel slag, magnesite and brucite or high SiO _2- . Thereby, the value of CaO / SiO _{2 and} the content of MgO can be adjusted without depending on the amount of the binder as described above. However, if a large amount of these additives or high SiO ₂ -containing ore is blended, the amount of gangue is increased. Therefore, it is preferable to adjust CaO / SiO ₂ and MgO so that the gangue content becomes 0.25 or less.

In the present embodiment, as described above, numerical ranges of the carbon content (TC), CaO / SiO ₂ , gangue content and MgO content are specified. Experimental results showing the critical significance of these numerical ranges are shown below.

CaO / SiO ₂ is 1.5, the reduction rate was also measured in the sintered ore is 1.5% and the MgO content of unfired hamtan compacted light 1400 ℃. It is assumed that the unreduced iron is present in the slag as FeO, and the FeO concentration in the slag is calculated from the obtained reduction ratio. As a result, it was found that the FeO concentration in the slag was 34% in the case of using the sintered ores and 2% in the case of using the non-calcined hamsters. Using this FeO concentration, the relationship between the value of CaO / SiO ₂ or the content of MgO and the slag melting point was examined for the sintered or non-sintered sand blasted light. Further, the melting point of the slag _{(CaO-SiO 2 -Al 2 O} 3 -MgO-FeO) is, was determined from the simulation by a computer.

Figure 2 is when the MgO content of 1.5% shows the relationship between CaO / SiO ₂ and the slag melting point. 3 shows the relationship between the MgO content of the slag melting point in the case where the CaO / SiO ₂ is 1.5.

As apparent from Fig. 2, in the sintered light and the non-sintered sand blasted light, the effect of CaO / SiO ₂ on the melting point of slag is different. This is due to the difference in the reduction ratio at high temperature (i.e., the FeO concentration in the slag). Specifically, in the sintered ores, when the CaO / SiO ₂ is lowered by 1.0, the melting point of the slag decreases by 278 ° C. On the other hand, when the CaO / SiO ₂ ratio is lowered by 1.0 in the non-calcined hammerite compact, the slag melting point is lowered by 620 ° C. As a result, the effect of CaO / SiO _{2 in} the non-calcined hamsters compacted light is twice as large as that of CaO / SiO _{2 in} the sintered ores.

In the non-calcined hamsters compacted light, the reduction ratio at a low temperature is high. When the non-calcined hamstick compact having a large carbon content is used as compared with the calcined compacted light having a small carbon content, it is quickly reduced at the top of the blast furnace. Then, the amount of unreduced iron component (amount of FeO) remaining in the slag which is reduced at the upper portion and moves to the lower portion is reduced. When the amount of FeO in the slag is decreased, the slag melting point is increased. As described above, the melting point of the slag also depends on the basicity (CaO / SiO ₂ ). Therefore, it is considered that the slag melting point largely changes due to the basicity in the non-calcined hamsters compacted light. Further, if the basicity in the non-calcined hamlet compacted light is large, it is considered that the slag melting point becomes very high.

Further, referring to Fig. 3, in the sintered ores, when the MgO content is increased by 1.0%, the melting point of the slag is lowered by 50 캜. On the other hand, when the MgO content is increased by 1.0% in the non-calcined hammerite compact, the melting point of the slag is lowered by 22 ° C. As a result, the influence of the MgO content in the non-calcined hamsters compacted light is about half that of the MgO content in the sintered ores.

However, strictly speaking, the loading behavior is not determined solely by the melting point of the slag, but also depends on the amount of slag and other slag properties (such as viscosity and wettability with the metal). For this reason, the loading behavior is a complex phenomenon and is not fully explained at this time. However, it is apparent that in the sintered or non-sintered compacted light, the slag melting point is lowered and the component conditions for promoting the metal drop are different.

Therefore, the loading characteristics of non - calcined hamsters compacted with various gangue components were investigated using a load - softening tester.

Crushed iron raw materials and crushed raw materials were pulverized, mixed with binders and additives, and kneaded to obtain kneaded products. Next, the kneaded material was molded, and the formed body was cured for a predetermined period to produce non-burned hamstick compacted light. The carbon content TC (total carbon) of the non-calcined hamstick compact light was 20 mass%. And the mixing ratio of the iron-based raw material and the subordinate material was adjusted so that the content of CaO / SiO ₂ and MgO became a predetermined value. The blending amount of the binder (cement) was 10 mass%.

Specifically, the gangue amount _{[(CaO + SiO 2 + Al} 2 O 3 + MgO) / (100- carbon content (TC))] in the a constant to 0.22, the MgO content is constant at 0.9 mass%, CaO / SiO ₂ The blending amount of the Portland cement and the non-powdered zirconium was adjusted so as to be a predetermined value in the range of 0.5 to 2.5. Thus, different non-calcined hamsters compacted light was produced in the range of CaO / SiO ₂ of 0.5 to 2.5 as the gangue component.

In addition, CaO / SiO ₂ was kept constant at 2.0, and non-calcined hamstick compact having various MgO contents was produced.

First, load softening tests were carried out on different non-sintered hamsters compacted light in the range of CaO / SiO ₂ of 0.5 to 2.5 in terms of gangue component.

It was assumed that the actual blast furnace was used, and the non-sintered hammerite compact was mixed at a ratio of 10% with respect to ordinary sintered ores (CaO / SiO ₂ = 1.8). The metal amount (rate) dropped from the crucible was measured at the stage of heating and reducing to 1600 占 폚. Then, the metal loading rate (%) defined by the following equation was calculated.

Metal loading rate (%) = amount of drip metal / (total amount of Fe loaded × 0.95) × 100

The metal loading rate was similarly measured for the sintered ore only. When the metal loading rate of the sintered ores is less than 50%, the lower surface of the welded joint is lowered and the lower welded area is narrowed. As a result, the lower air permeability is deteriorated, and stable operation becomes difficult.

The obtained results are shown in Table 2 and Fig.

As can be seen from FIG. 4, the higher the CaO / SiO ₂ of the non-calcined hamsteak intense light, the lower the metal loading rate. In particular, when the CaO / SiO ₂ of the non-calcined hamsters compacted light exceeds 2.0, it is difficult to maintain a metal loading rate of 50%. Since the indirect reduction proceeds from the low-temperature region by using the non-calcined hamsters compacted light, the FeO content in the slag coexisting with the metal in the fused layer is lowered, and the slag melting point is raised. Generally, the iron melt produced by reduction contains carbon in the coke when it falls to the lower part of the furnace, and the carbon content is increased (reduction-generated metal carburization). As the slag melting point is raised, it is considered that the aggregation of the iron melt after the reducing metal carburization is interrupted, and the result shown in Fig. 4 is obtained. When CaO / SiO ₂ is less than 1.0, the slag dripping rate is less than 50%, although the coexisting slag melting point is sufficiently low. This is because the ratio of SiO _{2 as} a network former is increased, so that the viscosity of the coexisting slag is increased and the agglomeration of the metal is inhibited.

4 also shows a measurement result indicating the relationship between CaO / SiO ₂ of the sintered ores having an MgO content of 1.5% and the metal loading rate. Also in the sintered ores, the metal loading rate tends to decrease with the rise of CaO / SiO ₂ . However, the change is gentle. From the results shown in Fig. 4, it can be confirmed that the constituent conditions to be satisfied are different in order to achieve excellent metal drop-loadability in the non-calcined ham and loosened light mass and the sintered ores.

As described above, in order to improve the metal loading rate, it is necessary to set CaO / SiO ₂ to 1.0 to 2.0. The CaO / SiO ₂ is preferably 1.4 to 1.7, and a metal loading rate of more than 60% can be achieved.

Further, the load softening test was carried out on the non-sintered hammer tendon light having CaO / SiO ₂ of 2.0 and various MgO contents by the same method. Then, the relationship between the MgO content and the metal loading rate in the non-calcined hamsters compacted at a ratio of 10% to the sintered ores was investigated. The obtained results are shown in Table 3 and Fig.

As can be seen from Fig. 5, in order to improve the metal loading rate, it is also effective to raise the MgO content in the non-calcined hammer intruding light. When the MgO content is 0.5% by mass or more, the metal loading rate can be maintained at 50% by mixing the non-calcined hammerite light of CaO / SiO ₂ = 2.0 with the sintered ores at a ratio of 10% . The higher the MgO content, the higher the metal loading rate. However, from the vicinity of the MgO content of 2.0%, the effect is saturated. This is because the melting point of the above-mentioned low FeO slag (slag having a small FeO content) is lowered by MgO, and the effect of MgO can be effectively obtained as the CaO / SiO ₂ condition becomes higher.

Therefore, the MgO content is preferably 0.5% by mass or more. The upper limit is not specially set.

Further, also in the 5 CaO / SiO ₂ adjuster also indicate the measurement results indicating the relationship between the content of MgO of 2.0 ores and metal loading rate (%). Also in the sintered ores, the metal loading rate tends to increase with an increase in the MgO content. However, the change (influence) is larger than that of non-calcined hamsters. From the results shown in Fig. 5, it can also be seen that the constituent conditions to be satisfied are different in the non-calcined hamrate compacts and the sintered ores in order to achieve a superior metal drop-loadability.

Also, the amount of slag coexisting (amount of gangue + amount of unreduced FeO) is also an important factor determining the dripping property. Thus, non-calcined hamlet compacted light having CaO / SiO ₂ of 1.5 and MgO of 1.0% and having different gangue stones was produced. Then, the metal loading rate was measured and the loading characteristics were investigated.

The amount of gangue as described above was calculated by the following equation.

Gangue amount _{= (CaO + SiO 2 + Al} 2 O 3 + MgO) / (100- carbon content (TC))

The obtained results are shown in Table 4 and Fig.

As described above, since the FeO concentration in the slag is already lowered to 2% at the relatively low temperature portion, the influence of the FeO concentration is small. As a result, when the gangue content was 0.25 or less, good metal dropping property was exhibited regardless of the amount of slag. When the gangue content is 0.25 or less, it can be considered that the slag property, such as the solid phase rate, the viscosity, and the wettability with the metal, is more dominant than the amount of slag, which is the dominant factor of the metal drop load. However, when the gangue content exceeds 0.25, the influence of the amount of slag can not be ignored, and the dropping property is deteriorated. In addition, when the gangue content at this level (greater than 0.25) is used, the amount of run-away slag is remarkably increased when a large amount of unfired hammerized intense light is used in the blast furnace, and the operation for leaving slag is unstable, .

From the above results, it is preferable to adjust the unfired hamtan compacted light gangue component amount _{[(CaO + SiO 2 + MgO} + Al 2 O 3) / (100-TC)] is 0.25 or less so that the.

In addition, the effect of carbon content (T.C) on the non - calcined hammerhead light on the metal loading rate was investigated.

MgO is constant, a certain amount of gangue and 0.22 to 1.0 mass%, and CaO / SiO ₂ is 0.5, 1.0, 1.5, 2.0, or 2.5, and a carbon content (TC) 10, 15, 18, 25, or 30% by weight , The blending ratio of the raw materials was adjusted to prepare non-calcined hamsters compacted light.

The metal load (rate) was measured in the same manner as the above-mentioned method. The obtained results are shown in Fig.

From the results of Fig. 7, it can be seen that the metal loading rate decreases with the increase of the carbon content (T.C). This is because, as described above, the FeO concentration in the slag coexisting with the metal decreases with an increase in the carbon content (T.C).

As described above, in order to realize stable operation in the blast furnace, the metal loading rate needs to be 50% or more. It can be seen that when the carbon content (TC) is 25 mass% or less, the metal loading rate of 50% or more can be attained with CaO / SiO ₂ of 1.0 to 2.0. Therefore, it is necessary to set the upper limit value of the carbon content (TC) to 25 mass%.

In the present embodiment, the amount of non-calcined ham denatured light and the amount of gangue are adjusted to a predetermined range, but the molding method, shape, physical structure (porosity, porosity and the like) of the non-calcined ham denitric light is not limited. In the case of non-calcined sand blasted light for blast furnaces, various forms such as pellets and briquettes are applicable. Further, various molding methods such as extrusion molding can be applied, and an equivalent effect can be obtained.

In the blast furnace, the charge moves from the upper part to the lower part, and the reducing gas moves from the lower part to the upper part, whereby the heat exchange and the reaction proceed. For this reason, the blast furnace is a countercurrent reactor. In general, in the continuous operation of the blast furnace, the reducing power of the reducing gas is lost in the upper layer of the ore layer, so that the reduction can not proceed sufficiently. In particular, the calcined compacted light does not contain carbon and has no self-reducing ability. Therefore, in the case of using the fired compacted light, the fired compacted light is not sufficiently reduced at the upper portion of the ore layer. In the state where the reduction is incomplete, when the plasticized compacted light moves to the lower portion of the blast furnace, it is reduced to the blast furnace and the core portion of the blast furnace, thereby causing direct reduction. In such a case, there is a problem that the load on the blast furnace is increased and the air permeability is deteriorated.

On the other hand, when the non-calcined hamstick compact light of the present embodiment is used, the presence of the non-calcined hamstick compact light of the present embodiment together with iron ores in the blast furnace significantly reduces the reduction efficiency in the upper layer of the ore layer have.

However, in the non-calcined hamlet compacted light having a high carbon content, the effect on the slag melting point due to the basicity (CaO / SiO ₂ ) is large as described above (FIG. 2). In the present embodiment, the carbon content (TC) and CaO / SiO ₂ are specified based on the research results of the inventors of the present invention, thereby achieving a good metal drop loadability. As a result, the amount of slag strength between the enemy base and the core portion is reduced, and favorable air permeability can be ensured.

In addition, as described above, the presence of the non-calcined hamsters compacted light of the present embodiment together with iron ores in the blast furnace can remarkably improve the reduction efficiency particularly in the upper layer of the ore layer. The reduction efficiency in the upper layer of the ore layer, which is difficult to be reduced, can be greatly improved, so that the reduction efficiency in the whole blast furnace can be greatly improved. This makes it possible to reduce the amount of the reducing material that is larger than the coke amount of the same amount as the excess amount of carbon in the non-calcined hammer intense light of the present embodiment.

[Example]

(Sintered dust and iron ore) were prepared as raw materials for iron and iron, and carbonaceous materials (coke dust, powdered coke, and blast furnace first round) were prepared as raw materials for the hammer. As the binder, a cement (early strength Portland cement) was prepared. In addition, in some embodiments, a subsidiary material having a high SiO ₂ content was also used.

The blending amount of the raw material was adjusted so that the blending ratio of cement (crude steel portland cement) was 4 to 9 mass% and the mixing ratio of the carbonaceous material and the fine iron-containing material was varied. These raw materials were mixed together with water and kneaded with an IRISH mixer. The resulting kneaded product was assembled (formed) into a pan pelletizer to obtain a raw pellet. Subsequently, the green pellets were cured for two weeks to prepare non-calcined hamsters. The water content of the raw pellets was adjusted to 10 to 14 mass%, depending on the amount of cement to be mixed.

With respect to the obtained non-sintered hammer intense light, the cold crushing strength was measured in accordance with JIS M8718 by the following method. One sample was multiplied by the compression load at the specified pressing speed, and the load value when the sample was broken was measured. And a load value per unit cross-sectional area (kg / cm2) was obtained. The average value of 100 samples was calculated and used as the strength index.

The slag melting point and the metal loading rate of the non-calcined hamlet compacted light were measured by the above-mentioned method.

In addition, in the blast furnace having an effective volume of 5500 m 3, the blast furnace operation was carried out by using non-sintered hammer intruding light in an amount of 50 kg / tp as a part of the raw material. Then, the upper K value, the lower K value, the wind pressure fluctuation and the reduction ratio in the blast furnace operation were measured, and the average value of the operation results for about one month was obtained. The results are shown in Table 6.

Referring to Table 6, in the first embodiment, the components were optimized, and CaO / SiO ₂ was set at 2.0, MgO was set at 0.6%, and the amount of gangue was set at 0.22. When used in a blast furnace, the air permeability at the bottom of the furnace was improved, and the reduction ratio was reduced to 470 kg / tp. As a result, the effect of using non-calcined hamsters compacted light having a high carbon content was exerted.

Further, in the second embodiment, an additive having a high SiO ₂ content was blended and the content of SiO ₂ was increased to further lower CaO / SiO ₂ to 1.0. In this second embodiment, since the content of CaO / SiO ₂ and MgO was within an appropriate range, the slag melting point could be lowered. However, since the amount of gangue was increased to 0.28, the metal dropping property was slightly lowered, and the reduction ratio was not so decreased.

In the third embodiment, the amount of the binder is reduced to 4% in order to reduce the amount of gangue. However, since the content of the chemical component was appropriate, the metal loading rate was improved. However, since the amount of the binder was small, the cold crushing strength was insufficient at 85 kg / cm < 2 >. As a result, when used in a blast furnace, the amount of powder in the furnace was increased, whereby the upper air permeability was deteriorated, and the reduction cost ratio was slightly higher.

In the fourth embodiment, the content of the chemical components was adjusted by blending the additives without reducing the amount of the binder. As a result, it was possible to produce non-calcined hamstick compacted light with good metal dropping properties without damaging the cold crushing strength. When used in a blast furnace, the reducing cost was the lowest.

In the fifth embodiment, the amount of CaO / SiO ₂ and gangue is in the range (CaO / SiO ₂ : 1.0 to 2.0, gangue content: 0.25 or less) specified by the present embodiment, but the MgO content is set to 0.4% there was. As a result, the metal loading rate stood at 52%, reducing the reduction ratio, but the effect of reducing the reduction ratio was relatively small.

In contrast, the first comparative example, the carbon content (TC) is as low as 17 mass%, CaO / SiO ₂ is as low as 1.9, MgO content is to prepare a high unfired hamtan compacted light to 1.0%. The carbon content (TC) was low in some cases, and the melting point of the slag was sufficiently low, so there was no problem in dropping performance. However, when it is used in a blast furnace, since the carbon content is low, it is difficult to reduce the reduction cost.

In the second comparative example, non-calcined hamburger intruded light having a carbon content (TC) of 20% and a CaO / SiO ₂ of 2.2 was prepared. Since the reduction ratio at low temperature was improved, the slag melting point was remarkably increased. Also, since the CaO / SiO ₂ is more than 2.0, the metal dropping property is lowered. However, when used in a blast furnace, the air permeability at the bottom of the furnace deteriorated, and the fluctuation of the wind pressure remarkably increased. As a result, the operation became unstable. As a result, the effect due to the high carbon content could not be fully enjoyed, and the reduction ratio remained at the level of 500 kg / tp.

In the third comparative example, a high carbon non-calcined ham sandwich light having a carbon content of 30% and exceeding the upper limit of 25% by mass in the range specified by the present embodiment was produced. Since the content of other components was within a suitable range, the dropping rate was improved to 65%. However, the cold strength was as low as 60 kg / cm < 2 > and the minimum strength required for use in the blast furnace was not obtained. As a result, the amount of powder charged in the blast furnace increases, making it difficult to stabilize the long-term operation.

As described above, in the unfired hamtan compacted light, by a carbon content (TC) 18 to 25% by mass, CaO / SiO ₂ in the range of 1.0 to 2.0, and a metal dripping property is good, also when used in a blast furnace It can be seen that the reduction ratio can be lowered. In particular, the gangue amount or more _{(CaO + SiO 2 + Al 2} O 3 + MgO) / ( the value of the 100-carbon content (TC) 0.25 or less, and MgO content is 0.5 mass%, this effect is remarkable. In addition, these components By adjusting the addition amount of the additive and adjusting the blending amount of the binder to 5 to 10%, the crushing strength of the cold can be maintained.

The non-calcined hamlet compacted light for a blast furnace according to one embodiment of the present invention has a sufficient carbon content to improve the reduction ratio of not only non-calcined hamsters but also sintered rare-earth iron-containing raw materials for use in a blast furnace . Further, in the blast furnace operation, the melting point of the slag can be suppressed to be lower than that of the conventional art, and excellent reduction generating slag characteristics (metal dropping property) can be achieved.

Therefore, when the unfired hammer intense light according to one embodiment of the present invention is used as a part of the iron-containing raw material for blast furnace, good air permeability can be realized in the furnace under the blast furnace operation and the reduction ratio (coke ratio) .

In the method for producing non-calcined hamstick compacted light for a blast furnace according to one embodiment of the present invention, since the non-sintering process is applied, energy saving and lowering of CO ₂ can be achieved compared with a sintering process. Further, the dust generated in the iron-making process can be recycled as the iron-containing raw material and the carbonaceous material by a relatively inexpensive and simple method.

Therefore, one form of the present invention can be suitably applied to the technical field related to the hammer-intense light used in the blast furnace.

Claims (8)

Mixing and kneading 4 to 10% by mass of a binder with respect to the raw material for cast iron, the raw material for hammer and the whole raw material, kneading the kneaded material to obtain a molded body, curing the molded body,
Carbon content (TC) is 18 to 25 mass%, the gangue components SiO ₂ content of 5.1 to 10 mass%, CaO content (mass%) and SiO ₂ content (mass%) ratio CaO / SiO ₂ of 1.0 to 2.0, And a MgO content of 0.5 mass% or more. Mixing and kneading 4 to 10% by mass of a binder with respect to the raw material for cast iron, the raw material for hammer and the whole raw material, kneading the kneaded material to obtain a molded body, curing the molded body,
A CaO / SiO ₂ ratio of the Ca content (mass%) to the SiO ₂ content (mass%) of 1.0 to 2.0, and a Ca content of 6 to 10 mass%, a carbon content (TC) of 18 to 25 mass%, a gangue content of 6 to 10 mass% Wherein the MgO content is 0.5% by mass or more. Article according to any one of the preceding claims, CaO content (% by weight), SiO ₂ content (mass%), Al ₂ O ₃ content (% by weight), MgO content (mass%) and carbon content (TC) (% by weight ) the amount of gangue _{[(CaO + SiO 2 + Al} 2 O 3 + MgO) / (100- carbon content (TC))] value of 0.25 or less, unfired hamtan compacted light for the blast furnace is indicated by. A forming step of forming a molded body by mixing and kneading 4 to 10% by mass of a binder with respect to the raw material for ham iron, the raw material for hammer and the whole raw material,
Subsequently curing the molded body to obtain non-burned hamstick compacted light,
The unfired hamtan compacted light carbon content (TC) is 18 to 25 mass%, non-CaO / SiO in the 5.1 to 10 mass% SiO ₂ content of the gangue component, CaO content (mass%) and SiO ₂ content (mass%) ₂ is 1.0 to 2.0, and the MgO content is 0.5 mass% or more. In the step of forming the molded article, at least one blending condition selected from the group consisting of the ore item and the binder blend amount is adjusted. (METHOD FOR MANUFACTURING NON - FERROUS HAMMATIC LIGHT SOILS FOR BLAZES). A forming step of forming a molded body by mixing and kneading 4 to 10% by mass of a binder with respect to the raw material for ham iron, the raw material for hammer and the whole raw material,
Subsequently curing the molded body to obtain non-burned hamstick compacted light,
The unfired hamtan compacted light carbon content (TC) is 18 to 25 mass%, non-CaO / SiO ₂ of the CaO content of the gangue component of 6 to 10 mass%, CaO content (mass%) and SiO ₂ content (mass%) Of at least one selected from the group consisting of an ore item and an amount of binder in the step of forming the molded article so that the content of MgO is 1.0 to 2.0 and the content of MgO is at least 0.5 mass% A method for manufacturing non-calcined hamsters compacted for use. Of claim 4 or claim 5, wherein the unfired hamtan compacted light CaO content (% by weight), SiO ₂ content (mass%), Al ₂ O ₃ content (% by weight), MgO content (mass%) and carbon content in the forming process of the molded body, (TC) so that the gangue amount less than the value of _{[(CaO + SiO 2 + Al} 2 O 3 + MgO) / (100- carbon content (TC))] 0.25 represented by (% by weight), Wherein the blending conditions are adjusted. 5. The method according to claim 4, wherein at least one or both of an additive selected from quartz, serpentine, olam rock, dolomite, nickel slag, magnesite, brucite and high SiO _2-
The unfired hamtan compacted light carbon content (TC) is 18 to 25% by mass, 5.1 to 10% by weight of SiO ₂ content of the gangue component, CaO content and SiO ₂ content of the non-CaO / SiO ₂ is 1.0 to 2.0, and MgO Wherein the blending amount of either or both of the subsidiary material and the high SiO ₂ -containing ore is adjusted so that the content is 0.5 mass% or more. The method of claim 5, wherein, in the forming step of the formed body, silica, serpentinite, peridotite, dolomite, nickel slag, magnesite, further blended with one or both of the additives and the high SiO ₂ containing ore is selected from brucite,
The unfired hamtan compacted light carbon content (TC) is 18 to 25 mass%, the CaO content is 6-10% by weight of the gangue component, the CaO content and the SiO ₂ content ratio CaO / SiO ₂ is 1.0 to 2.0, and MgO content Wherein the blending amount of either or both of the subsidiary raw material and the high SiO ₂ -containing ore is adjusted so that the content of the inorganic filler is 0.5 mass% or more.

Images