slag splashing technique in converter operation

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 Slag Splashing technique in Converter Operation: Slag splashing has become a powerful tool to be used by the steelmaker to increase furnace life, maximize production from existing equipment and reduce refractory and gunning costs. Slag splashing is a very effective means of improving the furnace, it is through the impact o f hi gh-speed jet of nitrogen left after a steel furnace slag, the s l ag (the s l ag composition is adjusted) in the shortest possible evenly spray coating the time the converter lining in the whole surface and form a certain thickness and a dense layer of slag splashing, splashing slag layer prevents the converter s l ag, furn ace gas erosion of the lining, so to play the role of improving the furnace. Process Process steps are as follows: During the slag splashing process three main stages have been identified in the formation of the slag protective coating: transport of molten slag to the co nve rter wall s, adheren ce o f the mol ten slag to the sidew alls, and freezi ng and hardening of the slag layer . When the molten slag is transported to the co nve rter sidewall s, two transpo rt mechani sms are present: wash c oatin g and ejection coating . The first one occurs due to the bulk movement of the mol ten s l ag to ri se ab ove the i nit i al level and the second one due to the ejection of slag droplets which adhere to the vessel sidewalls . The in flue nce o f the s l ag density on the s lag sp l ashing proc ess i s anal yzed usin g computational fluid dynamics simulations. Values of the slag density ranging from 2000 to 3000 kg  m 3  are considered. This range is typical of CaO   SiO 2 molten slags found in steelmaking. Physical dimensions of the converter correspond to an actual industrial steelmaking converter of 150 metric tons. The volume fraction of slag in the converter sidewalls is employed for quantitative evaluation of the slag splashing efficiency. In order to detect spitting of slag from the converter mouth, the global mass balance is determined. Besides, the effect of the nitrogen jet Mach number on the slag splashing is simulated.

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Page 1: Slag Splashing Technique in Converter Operation

8/11/2019 Slag Splashing Technique in Converter Operation

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Slag Splashing technique in Converter Operation:

Slag splashing has become a powerful tool to be used by the steelmaker to increase

furnace life, maximize production from existing equipment and reduce refractory

and gunning costs.

Slag splashing is a very effective means of improving the furnace, it is through the

impact of high-speed jet of nitrogen left after a steel furnace slag, the slag (the slag

composition is adjusted) in the shortest possible evenly spray coating the time the

converter lining in the whole surface and form a certain thickness and a dense layer

of slag splashing, splashing slag layer prevents the converter slag, furnace gas

erosion of the lining, so to play the role of improving the furnace.

Process

Process steps are as follows:

During the slag splashing process three main stages have been identified in

the formation of the slag protective coating: transport of molten slag to the

converter walls, adherence of the molten slag to the sidewalls, and freezing

and hardening of the slag layer . When the molten slag is transported to the

converter sidewalls, two transport mechanisms are present: wash coating

and ejection coating . The first one occurs due to the bulk movement of the

molten slag to rise above the initial level and the second one due to the

ejection of slag droplets which adhere to the vessel sidewalls .

The influence of the slag density on the slag splashing process is analyzed using

computational fluid dynamics simulations. Values of the slag density ranging from2000 to 3000

 

kg 

m−3

 are considered. This range is typical of CaO – SiO2molten slags

found in steelmaking. Physical dimensions of the converter correspond to an actualindustrial steelmaking converter of 150 metric tons. The volume fraction of slag in

the converter sidewalls is employed for quantitative evaluation of the slagsplashing efficiency. In order to detect spitting of slag from the converter mouth,

the global mass balance is determined. Besides, the effect of the nitrogen jet Machnumber on the slag splashing is simulated.

Page 2: Slag Splashing Technique in Converter Operation

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Factor affecting the Slag Splashing Technique

Main factors which affect the splashing process are: operating parameters (jet

speed, angle of injection, lance height, molten slag height), and slag properties

(viscosity, density, surface tension).

Shear forces required to break the molten slag bath to form drops which are

ejected and adhered to the furnace walls are strongly dependent on jet speed and

viscosity of molten slag. In this work the influence of slag viscosity on the

splashing efficiency is analyzed by means of Computational Fluid Dynamics

(CFD) simulations. An industrial furnace is geometrically modeled, and severalvalues of viscosity are employed in the computer 2D transient simulations. First,

the mathematical models employed to represent fluid flow, continuity, turbulence,

 boundary conditions, multiphase flow and a parameter to quantify the efficiency of

the slag splashing process are presented. Then, the parameters employed in the

CFD computer simulations are defined.

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Advantage of Slag Splashing Technique

1. 

Slag splashing helps in recycling of the steel making slag.2.

 

The melting of the low melting phase of the slag lining results in therapid formation of a basic slag and the rapid dissolution of the CaO from

slag coating by SiO2 in converter slag. This leads to rapidde- Phosphorisation.

3. 

Lesser consumption of flux because of dissolution of basic slag duringthe steel making process.

4. 

Yield improvement due to lesser slopping because of increase in theconverter volume.

5. 

Increase in the lining life of the converter.