What is the fundamental building unit in solid silica and molten silicates?
The silicate tetrahedron SiO4.
What is the relationship between Carbon in the steel and Iron Oxide within the slag? At which carbon concentrations is that realtionship valid?
Valid at C<0.10%
Which oxides form polymeric chains in slag?
SiO2 and Al2O3.
Which oxides help to break down polymeric chains in slag?
CaO, FeO, MgO, and CaF2.
What determines the color of slag?
The content of iron oxides; rich in Fe oxides leads to "black" slag, poor in Fe oxides results in "white" slag.
What is the melting temperature of silica (SiO2)?
1725°C
How is the basicity ratio in slags calculated?
It's a weight ratio, often calculated using the Mannesmann ratio
how should the viscocity be in slags?
It should be low (=more fluid) to favor slag/metal reactions but not too low to avoid damage to refractory bricks.
How does the silica content affect the surface energy of slags and name the typical surface energy?
The surface energy decreases as the silica content increases.
200-600 mN/m
Why is a high bacisity index important?
It decreases the content/solubility of Iron Oxides.
What influences the concentration of Iron oxides in the slag?
The basicity ratio and the temperature.
The lower the basicity ratio the larger the concentration
The higher the temperature the larger the concentration
What are liquid iron slag reactions?
Desulfurisation
Dephosphorization
Which factors influence the desulfurization?
increase with increasing temperature
increase with increasing basicity index
increase with decreasing oxygen content
C and Si should be high
What does the Turkdogan Analysis focus on?
The sulphur capacity of the slag
How is slag involved in the desulfurization process in steelmaking?
Sulfur is transferred from the metal to the slag.
What is the role of lime in the de-sulfurization process?
Lime reacts with sulfur to form calcium sulfide, aiding its removal.
How do temperature and basicity influence desulfurization?
Higher temperatures and basicity improve desulfurization efficiency.
What are methods for desulfurization that do not include CaO?
Using calcium carbide or magnesium particles.
The particles are injected using a N2 carrier gas
What is the main reaction in dephosphorization?
The reaction between phosphorus and oxygen to form phosphorus pentoxide. Which is captured in the slag.
What are influencing factors for dephosphorization?
Decrease in Temperature decreases Desphosphorization
Increase in Oxygen increases Desphosphorization
Inrease in CaO (Lime) increases Desphosphorization
What is the significance of the Turkdogan analysis in slag study?
It helps in understanding the slag's capacity for sulfur removal.
What factors influence the slag-metal reaction rate?
Temperature, slag composition, and surface energy.
How is slag used in electric arc furnaces (EAF)?
As a medium for removing impurities and protecting the furnace lining.
What are the main components of synthetic slags?
Al2O3 and other specifically added oxides.
Last changeda year ago
