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?
Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?
Write chemical reactions taking place in the extraction of zinc from zinc blende.
State the role of silica in the metallurgy of copper.
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.
The impurity that is added externally to remove the impurity already present in the ore is known as ____________.
For the reduction of \[\ce{FeO}\] at the temperature corresponding to point D, which of the following statements is correct?
Wrought iron is the purest form of iron. Write a reaction used for the preparation of wrought iron from cast iron. How can the impurities of sulphur, silicon and phosphorus be removed from cast iron?
The purest form of iron is prepared by oxidising impurities from cast iron in a reverberatory furnace. Which iron ore is used to line the furnace? Explain by giving reaction.
The mixture of compounds A and B is passed through a column of \[\ce{Al2O3}\] by using alcohol as eluant. Compound A is eluted in preference to compound B. Which of the compounds A or B, is more readily adsorbed on the column?
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:
Carbon and hydrogen are not used as reducing agents at high temperatures.
Carbon deposition reaction taking place in ______.
Assertion: For the extraction of iron, haematite ore is used.
Reason: Haematite is a carbonate ore of iron.
