Softening and Melting Characteristics of Self-fluxed Pellets with and without the Addition of BOF-slag to the Pellet Bed.

Zuo, Guokun

doi:10.2355/isijinternational.40.1195

Cited by 18 publications

(19 citation statements)

References 2 publications

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“…Accordingly, a Fe 2 O 3 -CaO combination, containing 20-30 % lime is expected to be compatible with BOF conditions in view of low softening point, faster dissolution and early formation of FeO rich slag would accelerate refining of the bath. Guangqing Zuo 16) has reported that BOF slag with high FeO and Fe 2 O 3 content (16.4 % and 8.08 % respectively) shows very low softening point (1 400°C), but, when its FeO and Fe 2 O 3 content reduced to a low level (5.3 % and 1.5 % respectively) shows high softening point (1 520°C). Therefore, development of lime fluxed iron oxide in suitable agglomerated form viz.…”

Section: Introductionmentioning

confidence: 99%

Development of Fluxed Iron Oxide Pellets Strengthened by CO2 Treatment for Use in Basic Oxygen Steel Making

et al. 2009

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Lump lime is presently being used as a fluxed material in basic oxygen steel making process. However, problems are often encountered in operation due to its high melting point, poor dissolution property, fines generation and hygroscopic property. Binary CaO-Fe 2 O 3 has a eutectic point (1 200°C) with 22 % CaO. An agglomerate of lime and iron oxide under BOF condition would thus generate low melting oxidizing slag at the beginning of blow and would facilitate refining process. In this study, lime fluxed iron oxide pellet has been prepared using waste iron oxides and its strength was developed by CO 2 /CO 2 containing gas treatment at room temperature, while no separate binders has been used. Industrial waste gases, say, blast furnace gas (BFG) may suitably be used as CO 2 source. The pellet making process parameters such as composition of pellets, grain size of iron ore fines, treatment conditions etc. have been optimized through physical characterization like cold compressive strength, drop strength, abrasive resistance etc. Up to around 30 kg/pellet cold compressive strength, around 150 drop strength and excellent abrasive property have been achieved.

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Section: Introductionmentioning

confidence: 99%

Development of Fluxed Iron Oxide Pellets Strengthened by CO2 Treatment for Use in Basic Oxygen Steel Making

et al. 2009

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“…A low, narrow inverted "V" shaped cohesive zone is generally desirable to improve blast furnace performance. While extensive effort has been made to measure the softening and melting behaviour of blast furnace ferrous burdens, [31][32][33][34][35][36][37] information on the influence of alumina on such behaviour is very limited. It is expected that the effects of alumina on the physicochemical properties of the primary melt during sintering and the mineralogy of sinter will play an important role in determining the softening and melting behaviour.…”

Section: )mentioning

confidence: 99%

Effects of Alumina on Sintering Performance of Hematite Iron Ores

2007

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The integrated blast furnace and oxygen steelmaking (BF-OSM) route is still a dominant process for worldwide steel production, currently producing more than 60 % of the world's total output of crude steel. The counter-current principle on which the blast furnace operates makes it reliant heavily on the quality of its burden to maintain a sufficient level of gas permeability in its upper shaft and of liquid and gas permeability in its lower part. Iron ore sinter, constituting a major proportion of blast furnace burden in most countries, particularly in the Asia-Pacific region, is therefore expected to have a significant impact on blast furnace performance.The chemical composition of iron ore fines, together with the thermal conditions that sinter blends are subjected to, plays an important role in forming the primary melt during the sintering process and consequently determines the sinter structure and quality. Considerable emphasis has therefore been placed on the chemical composition and consistency of iron ore fines, particularly in terms of alumina content. However, due to the limited reserves and increasing depletion of high-grade iron ore resources, the alumina content of iron ores is expected to increase gradually. While the increase in such constituents is relatively slow over a long period, it has still caused problems for blast furnace operators.This paper attempts to clarify the role of different types of alumina present in iron ore fines and their effects on melt formation, sinter structure and sinter quality, as well as the sintering process itself. Mechanisms responsible for the deterioration of the low temperature reduction degradation characteristics (RDI) of sinter due to the increasing alumina content are also reviewed. In addition, potential measures to counter the adverse impacts of alumina on sintering performance of hematite iron ore fines are also discussed.KEY WORDS: High alumina iron ores; kaolinite; gibbsite; melt formation; sinter structure; sintering performance, sinter quality.ISIJ International, Vol. 47 (2007), No. 3, pp. 349-358 Review 349 © 2007 ISIJ alumino-silicates like kaolinite (Al 2 O 3 · 2SiO 2 · 2H 2 O), while the A type ores contain gibbsite (Al(OH) 3 ). 9) Extensive work has been conducted on the effects of alumina on sinter structure, quality and productivity. 1,2,[4][5][6][9][10][11][12][13][14] While the results are not conclusive and sometimes contradict each other, it is generally believed that too much alumina impairs the sinter quality, particularly the low temperature reduction degradation characteristics. However, much of the previous work showing the strong adverse effects of alumina on sinter quality and the sintering process has been focused mainly on Indian ores, 1,[4][5][6]9) which often belong to A type iron ores. Only limited work has been conducted on the majority of iron ores that contain alumina in the form of kaolinite. 2,10,12) From high temperature X-ray diffraction studies on Fe 2 O 3 -SiO 2 -CaO-Al 2 O 3 ores, it has been found that kaolinite ty...

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“…[16][17][18][19] To enable comparison of our findings with those of a previous study using a Sn alloy/chloride system, 3) the same experimental conditions as those in the previous study were adopted in the present study, including the sampling method, height of each liquid phase, gas flow rate, and composition of the Sn alloy.…”

Section: Methodsmentioning

confidence: 86%

“…(6) for the oxide and chloride systems. 3,[14][15][16][17][18][19][22][23][24][25] It was clear that the difference in the parameter (μ s /μ m ) 0.15 between the two systems was much larger than the difference in other parameters. Therefore, the difference in the viscosity of the upper phase between the two systems might be the key factor governing he difference in the droplet size between the systems.…”

Section: Size Of Metal Dropletsmentioning

confidence: 99%

Metal Emulsion in Sn Alloy/oxide System by Bottom Gas Injection

et al. 2017

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A metal emulsion is formed by the passage of gas bubbles through the interface between the metal phase and the slag phase in the steelmaking process. Emulsified metal droplets have great potential to improve the chemical reaction efficiency during motion in bulk slag. Several studies have focused on the formation mechanism of metal droplets and on the influence of the physical properties of the system on this mechanism. In this study, Sn alloy and sodium tetraborate were used to simulate molten steel and slag, respectively. Gas bubbles were introduced from the bottom of a molten metal bath at various gas flow rates. Slag containing metal droplets at the center of the slag phase was sampled, and the metal droplets were extracted by the dissolution of the oxide in a solvent. The number and diameter of the droplets were measured using a digital microscope. Under the same experimental conditions, the number of metal droplets in the oxide system was smaller but their size was larger than those in a previously investigated Sn alloy/chloride system. In both the systems, the total mass of metal droplets formed by a single bubble increased with an increase in the volume of the gas bubble, and when the volume of the gas bubble was small, the total mass of droplets in the oxide system was smaller than that in the chloride system. The sedimentation rate and coefficient in the oxide system were lower than those in the chloride system.

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Softening and Melting Characteristics of Self-fluxed Pellets with and without the Addition of BOF-slag to the Pellet Bed.

Cited by 18 publications

References 2 publications

Development of Fluxed Iron Oxide Pellets Strengthened by CO2 Treatment for Use in Basic Oxygen Steel Making

Development of Fluxed Iron Oxide Pellets Strengthened by CO2 Treatment for Use in Basic Oxygen Steel Making

Effects of Alumina on Sintering Performance of Hematite Iron Ores

Metal Emulsion in Sn Alloy/oxide System by Bottom Gas Injection

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