Advertisements
Advertisements
Question
Write down the reactions taking place in different zones in the blast furnace during the extraction of iron.
Advertisements
Solution
During the extraction of iron, the reduction of iron oxides takes place in the blast furnace. In this process, hot air is blown from the bottom of the furnace, and coke is burnt to raise the temperature up to 2200 K in the lower portion itself. The temperature is lower in the upper part. Thus, it is the lower part where the reduction of iron oxides (Fe2O3 and Fe3O4) takes place.
The reactions taking place in the lower temperature range (500 − 800 K) in the blast furnace are:
\[\ce{3Fe2O3 + CO -> 2Fe3O4 + CO2}\]
\[\ce{Fe3O4 + 4CO -> 3Fe + 4CO2}\]
\[\ce{Fe2O3 + CO -> 2FeO + CO2}\]
The reactions taking place in the higher temperature range (900-1500 K) in the blast furnace are:
\[\ce{C + CO2 -> 2CO}\]
\[\ce{FeO + CO -> Fe + CO2}\]
The silicate impurity of the ore is removed as slag by calcium oxide (CaO), which is formed by the decomposition of limestone (CaCO3)
\[\ce{CaCO3 -> CaO + CO2}\]
\[\ce{CaO + SiO2 -> \underset{(Slag)}{\underset{Calcium silicate}{CaSiO3}}}\]
RELATED QUESTIONS
The reaction,
Cr2O3 + 2Al → Al2O3 + 2Cr
(ΔGθ = -421kJ) is thermodynamically feasible as is apparent from the Gibbs energy value. Why does it not take place at room temperature?
Write chemical reactions taking place in the extraction of zinc from zinc blende.
The choice of a reducing agent in a particular case depends on thermodynamic factor. How far do you agree with this statement? Support your opinion with two examples.
Write chemical reactions taking place in the extraction of copper from Cu2 S.
How will you convert the following:
Zinc blende to Zinc metal
The impurity that is added externally to remove the impurity already present in the ore is known as ____________.
In the extraction of copper from its sulphide ore, the metal is formed by the reduction of \[\ce{Cu2O}\] with ______.
In the metallurgy of aluminium ______.
Choose the correct option of temperature at which carbon reduces \[\ce{FeO}\] to iron and produces \[\ce{CO}\].
Below point ‘A’ \[\ce{FeO}\] can ______.
For the metallurgical process of which of the ores calcined ore can be reduced by carbon?
(i) Haematite
(ii) Calamine
(iii) Iron pyrites
(iv) Sphalerite
How is copper extracted from low grade copper ores?
Why is sulphide ore of copper heated in a furnace after mixing with silica?
Explain the following:
\[\ce{CO2}\] is a better reducing agent below 710 K whereas \[\ce{CO}\] is a better reducing agent above 710 K.
Explain the following:
Silica is added to the sulphide ore of copper in the reverberatory furnace.
Explain the following:
Carbon and hydrogen are not used as reducing agents at high temperatures.
A cuprous ore among the following is:-
