Question

Which of the following statements is not true about extraction of iron from its ore in blast furnance?

Ellingham diagram:

• A. At 1500 K, iron oxide get reduced to Fe by CO and C
• B. At 673 K, iron oxide get reduced to Fe by CO and C
• C. At lowest part of the furnance coke is burnt at highest temperature
• D. Iron obtained from blast furnance is Pig iron

Answer 1

The correct option is B At 673 K, iron oxide get reduced to Fe by CO and C

In extraction of iron from its oxide ore, hot air in blown from bottom of blast furnace so that coke is burnt to give high temperature upto 2200 K at lower portion of furnace only.
Then, CO and heat moves to upper part of furnace.
The temperature is lower in upper part where the iron oxide get reduce in different temperature.

At 500-800 K, iron oxide get reduced only by CO.
$3F{e}_2{O}_3+CO\to 2F{e}_3{O}_4+C{O}_2$
$F{e}_3{O}_4+4CO\to 3Fe+4C{O}_2$
$F{e}_2{O}_3+CO\to 2FeO+C{O}_2$

At 900-1500 K, iron oxide is reduced by both C and CO.
$C+C{O}_2\to 2CO$
$FeO+CO\to Fe+2CO$

The iron obtained from furnace contains 4% carbon and impurities like P, S, Si, Mn known as Pig iron.