Exercise V
The input and output of a blast furnace are:
Iron ore: 
Coke: 
Limestone 
Pig Iron: 
Top Gas 
Assume some iron is lost as  in slag. Per ton of pig iron there is 1.82 tons of ore is used
Determine:
a) Amount of coke/ton of pig iron.
b) Composition of slag/ton of pig iron.
c) Perform oxygen balance and comment.
Solution:
Carbon balance:
Carbon from coke + carbon from  and  in pig iron + carbon in gases
Substituting values give coke =1000.37 kg
Composition of slag: It consists of  .
 in slag can be calculated from Si balance  in slag can be obtained from  . Similarly,  and  balance can be done to obtain respective oxides.
Amount of slag = 742.78 kg
SiO2
|
percent |
40 |
Al2O3 |
7.5 |
MnO |
1.8 |
CaS |
1.1 |
CaO |
36.0 |
MgO |
0.5 |
FeO |
13.12 |
|
Amount of top gas  pig iron
Amount of air (from  balance)  (c)
Oxygen balance:
Oxygen balance can be made air to compare answer in c.
 in top gas = 50.71 kg moles.
in top gas is from air and oxygen released from various oxides.
from air = 50.71 - released from oxides
During BF iron making:  are reduced and relesase oxygen. Decomposition of and  also releases oxygen.
Oxygen released = 18.057 kg moles.
from air = 32.653 kg moles
Blast volume = 3483 m3
This volume compases very well with that determined form balance.
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