Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B1/00—Preliminary treatment of ores or scrap
  • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
  • C22B1/16—Sintering; Agglomerating

Definitions

• the present invention relates to a sintered ore for blast furnace pig iron making using pisolite iron ore as a raw material and a method for producing the same.
• Sinter ore a major raw material of the blast furnace iron making method, which is a representative of iron making, is generally produced as follows. First, limestone about l Omm less iron ore fines, Doromai Doo, (referred to as CaO based Fukuhara fees) containing CaO auxiliary materials, such as converter slag, serpentine, silica, including S i 0 2 such as peridotite sub (referred to as S i 0 2 based auxiliary raw material) material, and coke powder, carbonaceous materials such as anthracite, further mixed with an appropriate amount of water, granulated.
• CaO auxiliary materials such as converter slag, serpentine, silica, including S i 0 2 such as peridotite sub (referred to as S i 0 2 based auxiliary raw material) material
• coke powder carbonaceous materials such as anthracite
• the quasi-granulated compounding material (pseudo-particles) is charged to a height of about 500 mm on a grate-moving sintering pallet, and the carbon material on the surface of the packed bed is ignited. .
• the carbon material is burned while sucking air downward, and the blended raw materials are sintered by the combustion heat generated at that time.
• the resulting sintered cake is crushed and sized to form a 3 to 5 mm
• the particles are charged into a blast furnace as a product sinter.
• sinters of powder unsuitable as blast furnace charging raw materials are called returned ore and returned as raw materials for sinter.
• Si 0 2 classified as Piso Lai preparative iron ore into one of iron ore is from 4.5 to 6% of the iron ore.
• the representative is Robe R iver of Australia, Yandi Kusina
• the basis of measures against pisolite iron ore is to suppress the rapid penetration of large amounts of melt into the cracks.
• a protective layer having a special composition on the surface around the ore as disclosed in Japanese Patent Application Nos. 1-184047 and 2-115730.
• these methods have the drawback that special auxiliary raw materials, as well as pre-granulation equipment or special raw material segregation charging equipment for the sintering machine are required.
• the present inventors thought that if the momentary amount of the melt existing around the pisolite iron ore could be limited to a very small amount, the infiltration of the melt could be suppressed, and a number of basic studies were conducted on the conditions for that. As a method of the present invention applicable to existing sintering machines.
• an object of the present invention is to provide an excellent quality sinter using iron ore, particularly pisolite iron ore, which is inexpensive and rich in resources.
• Another object of the present invention is to produce excellent quality sinter using the above iron ores without requiring special equipment.
• the present invention is as an iron-containing materials other than return ores.
• Pisorai preparative iron ore and S i 0 2 content of 1.5 mass% or less (all of the following percentages indicating the mass%) High
• an iron-containing raw material containing 40 to 70% of pisolite iron ore together with auxiliary materials, carbonaceous material, water, etc.
• iron-containing materials other than return ores to be provided to the sintering means Si0 2 content of less 60% of 1.5 or less of high-grade iron ore Al 2 0 3 ZSi0 2 of mass ratio of 0.3 or less of iron ore in it it is also possible to substitute a was even or, the Pisorai preparative iron ore, it is also possible to blend a slip metering of high-grade iron ore and low A1 2 0 3 iron ore to be 80% or more.
• the sintered ore obtained in this way has the same excellent yield and quality as hematite ore, which has been conventionally regarded as good quality.
• Figure 1 is a sinter iron ore in a single brand basicity Si0 2% and sintered ore in width 10 m or less of in the iron ore in the sinter produced in by Uni pan to be 1.6-2.2 It is a figure which shows the relationship of the ratio of a fine calcium carbonate slag.
• FIG. 4 is a graph showing the relationship between the ratio and the ratio of fine calcium carbonate and slag having a width of 10 / m or less in sinter.
• FIG. 3 is a view showing a microstructure of the sintered ore of the present invention.
• FIG. 4 is a view showing another microstructure of the sintered ore of the present invention.
• FIG. 5 is a diagram showing another microstructure of the sintered ore of the present invention.
• FIG. 6 is a diagram showing a microstructure of a conventional sintered ore.
• Figure 7 is a Pisorai bets iron ore and Si0 2 sintering pot test results of material consisting of 1.5% or less of iron ore, proportions and finished product yield of Pisorai bets iron ore accounts for both iron ore, sinter It is a figure which shows the relationship of JIS drop strength.
• FIG. 8 is Shoyuinabe test results, the ratio of Pisorai preparative iron ore in the raw materials Pisorai bets iron ore and Si0 2 is comprised of more than 1.5% iron ore 40 % Or to 70%, further the Si0 2 is the algebraic upgrade rate and finished products yield when a portion of 1.5% or less of iron ore Al 2 0 3 ZSi0 2 mass ratio was replaced with 0.3 or less iron ore, baked It is a figure which shows the relationship of the JIS fall strength of the condensate.
• FIG. 9 is Shoyuinabe test results, a 40% or 70% the proportion of Pisorai preparative iron ore in the raw materials Pisorai bets iron ore and Si0 2 is comprised of 1.5% iron ore, then its Si0 2 1.5 % or less of 60% iron ore replace Al 2 0 3 / Si0 2 weight ratio of 0.3 or less of iron ore, larger iron ore than 0.3 part ⁇ 1 2 0 3 ⁇ ⁇ 0 2 mass ratio thereof starting material
• FIG. 6 is a graph showing the relationship between the substitution rate, the product yield, and the JIS drop strength of sinter when sintering is performed.
• the feature of the method of the present invention is that the existing melt that changes every moment is kept to a very small amount as described above.
• the basic principle is that it promotes the generation of calcium ferrite (needle or plate with a width of 10 micron or less) that begins to be formed by the reaction between solid and liquid at approximately 1,200 ° C during the heating stage of the sintering process. It is.
• the cull shoe ⁇ beam Blow wells is generated as soon as the high CaOZSi0 2 of the melt occurs, a so-called melt generating rate-limiting, the melt amount that is actually present is very small.
• the present invention pursues the properties of the ore and the formation of this calcium ferrite.
• the present inventors have conducted single stocks sintering tests was adjusted to iron ore and limestone CaOZSi0 2 is usually within a range of sintered ore 1.6 to 2.2, 20 discussions section of the front and rear of the baked ore particles was polished, and the proportion of fine calcium ferrite with a width of 10 m or less on the cross section was quantified using an optical microscope equipped with a TV camera and an image analyzer. In addition, the coke 4% flour was added.
• Figure 1 shows the relationship between the content of 2 % Si0 in iron ore and the amount of fine calcium ferrite and slag with a width of 10 m or less.
• the amount of calcium ferrite slag can be considered to correspond to the amount of melt actually existing.
• Si0 2 in the iron ore is 1.5% or less was guided good generation of fine Karushiyuu Muferai bets.
• Figure 2 for Si0 2 is from 0.5 to 7.6% of the normal import ore in the iron ore, A1 2 0 3 Z Si0 2 weight ratio less the width 10 ⁇ m of fine local Shiyu um Blow wells and scan in the iron ore It shows the relationship of the amount of lag.
• Al 2 0 3 ZSi0 2 is that of 0.3 or less, or, Al 2 0 of Ru value the ore containing the 3 ZSi0 2 Si0 2 can be substituted with more than 1.5% of the ore.
• Fine-grained pisolite iron ore powder or intermediate particles adhering to other raw materials of about 0.5 mm or less include 3 granular hematite particles and iron oxide particles as shown in Fig. 5. (It grows up to 20-30 m in width, though it is part of the pole), and is very similar in structure to the coarse-grained pisolite iron ore in Fig. 4. Was. That is, the calcium sulfate connective tissue is a special feature.
• Microstructure 1 Densified pisolite iron ore particles surrounded by fine particles with a width of 10 m or less
• Microstructure 2 There are traces of pisolite iron ore particles but they are assimilated to granular particles and calcium ferrite.
• Tissue 3 Granular hematite particles and calcium silicate 4Tissue 4
• Granular hematite particles and glassy silicate Tissue 2 Magnetic particles, calcium carbonate and glassy silicate
• Microstructure Reoxidized hematite particles, magnetite particles, calcium ferrite and vitreous silicate
• the ratio of Not 2 to 5 pisolite iron ore is 40%-70% It can be seen that the area ratio of organizations 1, 2 and 3 is large in the range of ⁇ , and the total exceeds 80%.
• the reason why the structure 1 and the structure 2 increase at a low ⁇ 1 ratio of 30% pisolite iron ore is because the added Si02-based auxiliary material increases and is easily assimilated.
• the reason why the texture increases when the ratio of the iron ore of Noi 6 is as high as 80% is that the gas permeability of the bead is impaired and the combustion becomes uneven.
• Fig. 6 (a) unmelted residual In iron ore, large cracks are generated concentrically or from the surface to the center, and a number of irregular pores surround it, and the thickness of the wall between the pores becomes extremely thin, resulting in an extremely brittle structure .
• the porous part surrounding the residual pisolite iron ore is made up of granular matite particles combined with vitreous silicate as shown in Fig. 6 (b). And it has the characteristic of poor reducibility.
• the binder phase in Figs. 3 to 5 is calcium ferrite, which is known to be excellent in low temperature reduction powdering resistance and reducibility.
• the low-temperature reducible powder index (RDI) was significantly improved to 34 ⁇ 2 in the present invention, compared to 37 ⁇ 3 in the conventional method. Furthermore, looking at the pore structure in Figs. 3 to 5, it is not amorphous but round, and the thickness of the wall between the pores is also increased, resulting in high strength. This change in the pore structure is closely related to the fluidity of the melt, and the calcium ferrite-based melt has a high fluidity, and thus has an unambiguous relationship with the formation of the calcium ferrite bonded phase.
• Pisorai DOO iron ore and Si0 2 raw material consisting of 1.5% or less of iron ore results in baked Yuinabe test are shown in Figure 7. It is clear that the sinter ore yield and cold strength (JIS drop strength) are significantly improved when the ratio of pisolite iron ore, which is characterized by the above calcium sulfate composite phase, is 40-70%. It is. The low Si0 2 iron ore Runowa be lowered yield large active in more than 70% formulation is was melt itself as a binder phase decreases because Si0 2 is small.
• the mineral texture is a mixture of Figs. 3 to 5, and it has been confirmed that the total is 80% or more.
• Table 2 shows typical blended raw materials (mainly hematite ore) and their sintering operation results in actual equipment.
• Condition A in Table 3 is the sintering of only the iron oxide ore
• Condition B is the case where the proportion of the iron ore in the new raw material of the blended raw material in Table 2 is 30%.
• Conditions C and D are It is an example of the sintering operation result by the light method. The yield, production rate and cold strength of single grade of pisolite iron ore are remarkably reduced, and the yield is considerably lower than that of Table 2 when the percentage of pisolite in the new raw material is 30%.
• Si0 2 is as indicated by the condition C and D is blended under conditions of the present invention 1.5% or lower Si 0 2 iron ore, the current average yield shown in Table 2, production rate, and cold strength Equivalent characteristics were obtained.
• the present invention a portion of the low Si0 2 ore Pisorai preparative iron ore and Si0 2 is comprised et or 1.5% or lower Si0 2 iron ore raw materials Al 2 0 3 ZSi0 2 is 0.3 or less iron ore This is the result when the sintering is performed in the range of the above condition. In this case as well, the results as in Table 2 were obtained.
• Table 5 shows the result when a portion of the iron ore raw material mixture in Table 4 Al 2 0 3 ZSi0 2 is sintered and replaced by larger iron ore than 0.3.
• Yield and production rates were slightly lower than those of the normal raw materials in Table 2, but were much higher than those in Conditions A and B in Table 3, and the cold strength was almost the same as in Table 2.
• the yield of sinter ore It is possible to obtain the same results as before by using a large amount of pisolite iron ore, which has been regarded as a problem in order to lower the cost.
• the depletion of conventional high quality hematite ore is clear.
• the method of the present invention which makes it possible to use abundant and inexpensive pisolite iron ore in a large amount, can solve the resource problem and greatly contribute to reducing the cost of iron.

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• 1993
  • 1993-02-12 AU AU35743/93A patent/AU656060B2/en not_active Ceased
  • 1993-02-12 KR KR1019930703113A patent/KR960010579B1/ko not_active IP Right Cessation
  • 1993-02-12 WO PCT/JP1993/000184 patent/WO1993016203A1/ja active Application Filing
  • 1993-02-13 CN CN93102962A patent/CN1036210C/zh not_active Expired - Lifetime
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