Abstract

The Alkali metals enter the blast furnace through the raw materials. The alkali in the blast furnace form carbonates, cyanides and silicates at different temperature and heights of the furnace. At higher temperature zones the alkali move up along with the gases in form of vapors and when they reach lower temperature regions they condense on the downward charge materials. Alkali cause decrease in strength of the raw materials. They have catalytic effect on the Boudouard reaction. Alkalis lead to cracking of the refractories, scaffold formation and hanging. Alkali metals are removed with slag, with the off gas and rest circulates in the furnace. Other than the blast furnace Alkali have their negative effect on the other processes of an integrated steel plant like the agglomeration processes and also on the different alternative iron making processes like Corex etc. 

Keywords

alkali, blast furnace, catalytic effect, alkali circulation.