Question $1(40$ Marks$)$

$1\mathrm{.}1$ Calculate the weight of lime required in a $100$ ton LD converter to get a basicity of $3$ given that $80$ ton hot metal contains $0\mathrm{.}8\%$ Si and $20$ ton scrap containing $0\mathrm{.}15\%$ Si $($Assume there is no other source silica and that lime contains $90\%$ CaO$)[10$ marks$]$

$1\mathrm{.}2$ Explain why much more lime than calculated above $($question $1\mathrm{.}1)$ is charged in the LD vessel during blowing? $[10]$

$1\mathrm{.}3$ What problems are associated with using the type of lime above $($question $1\mathrm{.}2)?[4]$

$1\mathrm{.}4$ As a steel plant metallurgist, what precautions would you take to minimise the problems above $($question $1\mathrm{.}3)?[6]$

$1\mathrm{.}5$ Explain why lime is added in the early stages of the blow and in what ways is the bottom injection practice more beneficial? $[4]$

$1\mathrm{.}6$ What are risks associated with carried over slag and low CaO content in slag?$[4]$