Steel is The Iron that contain the Carbon lower than 1,7%, as figure 1.
Steel is very important for our life, more than 95% of the equipment is made of steel. In line with the increasing demand for steel, the main raw material requirements and support: Alloy, Refractory, Flux, Spare Parts, Energy etc. will also increase.
The material requirements for steelmaking can be seen as figure 2.
Figure 2. The Material Requirements of Steelmaking
The continous process of steelmaking can be seen as figure 3.
Figure 3. The Process of Steelmaking
The most important processes in the manufacture of steel is how to maintain the properties of steel produced. So, maintaining the composition by adjusting the impurity content is very important. Impurities are usually controlled, Sulfur, Phosphor, Silicon, as well as gas and other alloy material if used.
Desulfurization
In absence of carbon, silicon and aluminium in metal, the desulphurization reaction can be written as:
[S] + [Fe] + (CaO) = (CaS) + (FeO)
Sulphur distribution ratio will be higher if:
aCaO is high (higher basicity)
aFeO is low (reducing slag)
k‘ is high (higher temperature)
Figure 4. Melt and Slag in The Laddle ( From Dr. Ing. Zulfiadi Zulhan)
Figure 5. Bottom stirring of Desulphurization Process
Desiliconization
Silicon in metal is oxidized to SiO2, the reaction taking place is:
[Si] + 2[O] = (SiO2)
The partitioning between slag and metal will depend upond the activities of silicon and oxygen in metal and on the the activity of silica in slag
[Si] + 2[O] = (SiO2)
Dephosphorization
Phosphor in metal is oxidized to P2O5, the reaction taking place is:
2[P] + 5[O] = (P2O5)
The partitioning between slag and metal will depend upond the activities of Phosphorus Pentoxide and oxygen in metal and on the the activity of Phospor in slag
2[P] + 5[O] = (P2O5)
Desulphurization need Reductive Environment, but the Desiliconization and Dephosphorization need Oxidative Environment. Degassing is done with vacuum condition.
No comments:
Post a Comment