Correct Answer - Option 3 : 1, 2 and 3
Concept:
Among all steel making reactions, oxidation of carbon is the reaction whose product is gas i.e. CO.
‘Carbon boil’ is CO gas bubbling to the liquid steel surface. It is a manifestation of carbon removal from the melt via oxidation. Large C contents, as in steelmaking from pig iron, are removed by oxygen blown through the melt.
Advantages of Carbon Boil:
- Carbon Boil can induce stirring in metal and slag phases during steelmaking leading to homogenization of bath temperature and composition and less sloping.
- It is also responsible for increase in Metal-Slag, Metal-Gas and Slag-Gas interfacial area resulting in faster rate of reactions.
- It also helps in removal of inclusions.
- CO gas has a high calorific value and post combustion of CO in steel making can contribute to energy efficiency.
- When carbon bubble happens, it results into ensuing evacuation of hydrogen and nitrogen gases, at last creating clean steel.