Mechanisms of Iron Entrainment into Slag due to Rising Gas Bubbles.

Han, Zhijun; Holappa, Lauri

doi:10.2355/isijinternational.43.292

Cited by 58 publications

(48 citation statements)

References 15 publications

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“…7. Schematic illustration of entrainment of hot metal droplets into slag due to rising gas bubbles according to mechanism considered in [3].…”

Section: Formation and Behavior Of Different Metal Droplets In Slag Dmentioning

confidence: 99%

“…[1][2][3] This entrapment of the metal droplets by the slag can significantly increase the iron losses and, as a result, the cost of steel products at steel plants. Therefore, one important direction for increasing the steelmaking effectiveness and to decreasing of cost of steel products is a reduction of iron losses in slag during desulfurization of hot metal and steel.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Metal Droplets in Slag after Desulfurization of Hot Metal

2015

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Iron losses in slag during an intensive desulfurization of hot metal can reach 0.6-1.1% from the total amount of processed hot metal. The characteristics of different metal droplets (such as morphology, number, size, composition and solidification structure) in industrial slag samples after desulfurization were investigated using SEM. All metal droplets in the slag were classified into three groups according to morphology: Type A -spherical/oval; Type B -spherical/irregular; Type C -irregular. Thereafter, some mechanisms for involving of different metal droplets into the slag during desulfurization process were studied based on obtained characteristics of metal droplets. Moreover, a possibility to remove those metal droplets from the liquid slag was estimated based on Stokes law. In addition, the effect of some parameters (such as slag viscosity and size of different metal droplets in this slag) on the possibility to reduce the iron losses during desulfurization of hot metal was considered.

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“…7. Schematic illustration of entrainment of hot metal droplets into slag due to rising gas bubbles according to mechanism considered in [3].…”

Section: Formation and Behavior Of Different Metal Droplets In Slag Dmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of Metal Droplets in Slag after Desulfurization of Hot Metal

2015

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“…10) Han and Holappa 11) have observed the droplet formation behavior in a molten steel and slag system by using X-ray imaging equipment. They found two mechanisms of the droplet formation, i.e., jet entrainment and film entrainment.…”

Section: Influence Of Bottom Bubbling Condition On Metal Emulsion Formentioning

confidence: 99%

Influence of Bottom Bubbling Condition on Metal Emulsion Formation in Lead-Salt System

et al. 2010

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“…According to the in-situ X-ray observation, the iron droplets entrained into slag were mainly formed from two sources, jet entrainment and film entrainment. 10) The size distribution of iron droplets is desirable but difficult to measure. Small iron droplets often coalesced to form a bigger one when resting on the collector plate during the bubbling period.…”

Section: Effect Of Slag Viscositymentioning

confidence: 99%

“…The total entrainment is caused by both jet and film entrainment. 10) The volume of the denser liquid that will be entrained by a discrete bubble is strongly influenced by the fluid properties of both lighter and denser liquid. [2][3][4][5][6][7] However, the data is still quite rare, For a quantitative description of heat and mass transfer or reactions through metal droplets in slag, some uncertainties should be cleared up in respect to the quantity of droplet formation by gas bubbling according to the fluid properties of metal and slag.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Iron Entrainment into Slag Due to Rising Gas Bubbles

Han¹,

Holappa²

2003

ISIJ International

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Iron droplets can be entrained into the slag phase when gas bubbles pass through the molten iron/slag interface. The entrainment phenomena occurring during passage of single bubbles through the interface were investigated by using in-situ X-ray transmission (fluoroscopic) techniques and by collecting and measuring the entrained iron droplets. The effects of bubble size, interfacial tension and viscosity of the slag on the iron droplets entrainment were investigated. The results showed that the mass of the entrainment increased with the increasing bubble size, but decreased with increasing interfacial tension and slag viscosity. A dimensionless equation was proposed to describe the relation between the entrainment of metal into slag and the above-mentioned parameters. This information can be used to optimize heat and mass transfer processes e.g. in ladle metallurgy and to reduce the financial loss due to metal discard within the slag.KEY WORDS: entrainment; gas bubble; iron droplet; iron/slag interface. a bubble (typically 10-14 mm). The sharp edge of the hole on the downward side was ground smoothly by a diamond tool.In each typical experiment the furnace was preheated to 1 580°C, then an alumina crucible-capillary system and a graphite crucible were introduced into the furnace tube from the bottom and the top, respectively. The alumina crucible with 35 mm I.D. and 60 mm height contained 135 g iron sample. Four different alumina capillaries were used to produce bubbles with different size, their I.D./O.D. were 2/4, 1.6/3, 1/2 and 0.7/1.3 mm, respectively, all their length was 550 mm. The alumina plate was located inside the crucible above the iron charge. The graphite crucible with 35 mm I.D. and 65 mm height was filled with 55 g slag.After the furnace tube was purged by pure argon about 2 min, 90 % Ar plus 10 % H 2 mixture gas was introduced as protective atmosphere. The alumina crucible was moved upwards slowly to the high temperature zone, while the graphite crucible was moved gradually downwards to the furnace center. After the iron was partly melted and covered the mouth of the alumina capillary (the pressure curve appeared on the monitor screen), the graphite crucible was quickly moved downwards to be seated on the alumina crucible to melt the slag and allow it to flow onto the iron melt. The whole period of the crucible moving and materials melting took about one hour; during this period the gas flow rate from the capillary was very low (ϳ0.2 mL/min). After the iron and slag samples were totally melted, the alumina plate, with a density (about 3.8 g/cm 3 ) greater than the density of the slag (about 2.6-2.8 g/cm 3 ) but lower than that of liquid iron (about 7.1 g/cm 3 ), floated on the surface of the iron melt submerged in the liquid slag. When experiments with gas bubbles passing through the iron/slag interface were conducted both with and without the alumina plate, no significant differences were observed. When the gas flow rate was set to the proper value (normally, 1.7-5.0 mL/min), observation of the ...

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Mechanisms of Iron Entrainment into Slag due to Rising Gas Bubbles.

Cited by 58 publications

References 15 publications

Characterization of Metal Droplets in Slag after Desulfurization of Hot Metal

Characterization of Metal Droplets in Slag after Desulfurization of Hot Metal

Influence of Bottom Bubbling Condition on Metal Emulsion Formation in Lead-Salt System

Characteristics of Iron Entrainment into Slag Due to Rising Gas Bubbles

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