i) Discuss the conditions to remove simultaneously carbon and phosphorus from hot metal.
ii)What may be the cause of reversal of Mn from slag to metal and how can it be rectified?
iii)What is the importance of carbon removal in steelmaking?
iv)What is rimming reaction?
v)Derive the conditions for removal of sulphur in iron melt containing C, Si, Mn,S, and P. Based on the conditions, discuss whether sulphur removal can be achieved efficiently in ironmaking or in steelmaking.
Lectures 11 to 20
1)
Discuss the functions of a nozzle in converter steelmaking
2)
Given the expressions in lecture 13, calculate for a 200 ton converter the following;
a) Diameter of a nozzle for 4 hole lance
b) Oxygen supply pressure
c) Momentum flow rate produced by the four hole nozzle
d) Jet penetration depth when oxygen is blown at (a) 3m lance
distance, and (b)1.5 m lance distance
e) The effects produced by the jet on impinging the molten steel bath at distances mentioned in d.
3)
What is a foamy slag practice and what advantages this practice offers in electric steelmaking. How foamy slag is practiced (a) in plain carbon steelmaking and (b) in stainless steel making?
4)
Increasing cost of electric energy demands to use chemical energy in electric steelmaking. In what different ways chemical energy can be used? Discuss
5)
Consider 1000kg iron ore of composition and 20% gangue minerals. Reduction of iron ore produces DRI in which oxygen is present as .Calculate amount of free iron, amount of FeO and total gangue minerals for metallization ranging in between 85% to 95%free iron. Discuss the results with reference to usage of directly reduced iron in electric steelmaking.
6)
In stainless steel making using high carbon ferrochrome, decarburization of the melt is required. Calculate the as a function of temperature and partial pressure of CO.
7)
What is a foaming slag? Explain the formation of foamy slag in EAF. What are its advantages in EAF steelmaking practice.
8)
What is the role of oxygen lancing in EAF steelmaking?
9)
What is an oxy-fuel burner? Describe its functions in EAF Steelmaking.
10)
Explain how the metallurgical quality of DRI/HBI affects the electric power consumption in EAF
11)
A EAF is operating with 100% scrap. What modifications would it be required to use chemical energy?
12)
What is the equivalent carbon in DR and what is its significance?
13)
Name the sources og CO and H2 generation in EAF steelmaking.
14)
What are the requirements of injection of oxygen for decarburization and post combustion in EAF steelmaking?
15)
Calculate the amount of CO and Oxygen required generating chemical energy 30 kWh/ton of steel.
16)
Discuss the mechanism of foaming in EAF stainless steelmaking.
17)
Calculate the supply of thermal energy in each case when 1000 kg scrap from 25oC is heated to 250oC, 300oC and 400oC
and 20% gangue minerals. Reduction of iron ore produces DRI in which oxygen is present as 
.Calculate amount of free iron, amount of FeO and total gangue minerals for metallization ranging in between 85% to 95%free iron. Discuss the results with reference to usage of directly reduced iron in electric steelmaking.
as a function of temperature and partial pressure of CO.
