Question

Which of the following is incorrect for the extraction of iron from haematite ore?

• A. Hydraulic washing followed by magnetic separation is used to concentrate the iron ore.
• B. Calcination of iron ore is carried out in a blast furnace to reduce iron oxide to iron metal.
• C. Carbon monoxide formed in a blast furnace acts as a reducing agent for iron oxides.
• D. Crude iron obtained from blast furnaces has high carbon content which is nearly 5 %.

Answer 1

The correct option is B Calcination of iron ore is carried out in a blast furnace to reduce iron oxide to iron metal.

Haematite is one of the most important ores of iron.
Haematite ore is first crushed and grinded into the powdered form.
This powdered haematite is then concentrated through hydraulic washing followed by magnetic separation.
The concentrated iron ore contains some impurities in the form of the carbonate, which is removed by calcination in which the carbonate decomposes in the absence of air into carbon dioxide gas (volatile) that escapes out.

The concentrated ore converted into oxide by calcination and roasting is then fed into the blast furnace along with coke and limestone.
Here, coke gets oxidised to produce CO that acts as a reducing agent and results in the reduction of iron oxides into iron.
The iron produced in the blast furnace is known as pig iron and contains upto 5% carbon impurities.