Generation of Droplets in Slag-Metal Emulsions through Top Gas Blowing

Abstract

The behavior of metal droplets in a slag-metal-gas emulsion through impinging gas blowing was investigated experimentally using a cast iron-slag-nitrogen gas system at high temperatures. A mathematical model of the emulsification process for determining the generation rate, size distribution, and residence time of metal droplets has been developed and successfully validated using experimental data. From the present work, it was found that the generation rate and size distribution of metal droplets is strongly influenced by the ratio of the inertial force of blown gas to the surface tension and buoyancy forces of the liquid metal. A new dimensionless number, i.e. blowing number, which represents the ratio of inertial to surface tension and buoyancy forces and also the departure of the system from its stable condition defined by the Kelvin-Helmholtz criterion, is proposed. A functional relationship of generation rate and size distribution of metal droplets with the blowing number is proposed.KEY WORDS: droplet generation; droplet size distribution; residence time; impinging gas blowing; slagmetal emulsion; steelmaking.

Physical and Mathematical Modeling of Multiphase Flows in a Converter

“…145) M. Iguchi 146) exhaustively reviewed the mechanisms of the bubble and droplet generation in a bath subjected to bottom gas injection through a single-hole nozzle using many examples. Various influential factors like lance height and flowrate, 6,67,[85][86][87][147][148][149] bottom blowing nozzles and flowrate 69,78,142,[150][151][152] were elaborately investigated to illustrate the splashing and droplet generation behavior by means of water modeling and CFD simulations. The splashing and droplet generation under different flowrate can be seen in Fig.…”

“…On the one hand, droplet generation has both beneficial and detrimental effects. 116,148) The droplet increases the interfacial area, which in turn, increases the refining rate. 148) On the other hand, the splashing and droplet generation may cause a wearing of refractories or a skulling on the mouth of the vessels and lances, which can result in a loss of production.…”

“…116,148) The droplet increases the interfacial area, which in turn, increases the refining rate. 148) On the other hand, the splashing and droplet generation may cause a wearing of refractories or a skulling on the mouth of the vessels and lances, which can result in a loss of production. 145,152) Foamy slag, decreasing top gas flow rate and increasing lance height reduces metal losses and the skulling of the upper converter cone and converter mouth.…”

The Influence of Sulfur on Dephosphorization Kinetics Between Bloated Metal Droplets and Slag Containing FeO

“…Several researchers have studied aspects of droplet behavior relevant to steelmaking including, decarburization, [1][2][3][4][5][6] droplet generation, [7][8][9][10][11][12][13][14][15][16] size distribution, [17,18] and residence time. [19] Other workers have developed models [20][21][22][23] and conducted plant trials, [24][25][26][27][28] which considered the role of droplets in the overall process kinetics.…”

Comprehensive Model of Oxygen Steelmaking Part 2: Application of Bloated Droplet Theory for Decarburization in Emulsion Zone

“…The kinetic energy absorbed by a metal droplet from oxygen jet, EKd is calculated using; 25) ........................... (19) where RB and ud(0) denote droplet generation rate and initial velocity of droplets, respectively. This relationship is valid if the all produced droplets are in spherical shape.…”