2. SOME IMPORTANT TERMS-
NOTE-
Minerals: A solid element or compound which occurs naturally
in the Earth's crust is called a mineral.
Ore: A mineral from which metals can be extracted profitably is
called a metal ore. Profitable extraction means that the cost of
getting the metal out of the ore is sufficiently less than the amount
of money made by selling the metal. So All Ores Are Minerals
But All Minerals Are Not Ores.
The most common metal ores are oxides and sulphides. Metals
are obtained from their ores by reduction.
3. What is a Blast furnace??
It is a tall cylindrical furnace
made of steel.
It is lined inside with fire
bricks.
It is narrow at the top and
has an arrangement for the
introduction of ore and outlet
for waste gases.
Heated with help of Hot
Gases.
4. What are the functions of a Blast Furnace???
•The function of a
blast furnace is to
reduce and convert
iron oxides into liquid
iron called "hot metal".
•The blast furnace is a
huge, steel stack lined
with refractory brick.
•Iron ore, coke and
limestone are put into
the top, and preheated
air is blown into the
bottom.
5. Your own footer Ahan M R ,10-B
Steps involved in Blast furnace --
.
6. 10-B Ahan M R
• Step 1-Insert iron ore, limestone, and coke
into blast furnace.
• Step 2-Coke reacts with oxygen and forms
carbon dioxide- C(s)+O2(g) --> CO2(g).
• Step 3-Limestone decomposes and forms
another carbon dioxide- CaCO3(s) -->
CO2(g)+CaO(s).
7. 10-B Ahan M R
• Step 4-Carbon dioxide produced in the
first 2 reactions reacts with excess
coke and forms carbon monoxide-
CO2(g)+C(s) --> 2CO(g).
• Step 5-Carbon monoxide reduces iron
ore and produces molten iron-
3CO(g)+Fe2O3(s) --> 2Fe(l)+3CO2(g).
8. 10-B Ahan M R
• Step 6-The excess limestone from the
second reaction reacts with the sand
(coming from minerals in iron ore) and
forms calcium silicate (slag) -
CaO(s)+SiO(s) --> CaSiO3(l).
• Step 7-Slag and molten iron are drained
from the bottom of the furnace and gas
produced exits through holes in the top of
the furnace
9. Step 3 - Limestone decomposes and forms another carbon dioxide- CaCO3(s) --> CO2(g)+CaO(s)
Step 4 - Carbon dioxide produced in the first 2 reactions reacts with excess coke and forms carbon
mono xide-CO2(g)+C(s) --> 2CO(g).
Step 2 - Coke reacts with oxygen and forms carbon dioxide- C(s)+O2(g) --> CO2(g).
Step 6 - The excess limestone from the second reaction reacts with the sand (coming from minerals
in iron ore) and forms calcium silicate (slag) -CaO(s)+SiO(s) --> CaSiO3(l).
Step 1 - Insert iron ore, limestone, and coke into blast furnace.
Step 7 - Slag and molten iron are drained from the bottom of the furnace and gas produced exits
through holes in the top of the furnace .
Step 5 - Carbon monoxide reduces iron ore and produces molten iron- 3CO(g)+Fe2O3(s) -->
2Fe(l)+3CO2(g).
10. Why does Iron have to be extracted in a
Blast Furnace???
•Iron has to be extracted by the blast
furnace because it contains mud ,clay
,minerals , mixture of other metals and
some unwanted materials.
•In the furnace ,the iron is be displaced by
carbon.
•This is more efficient method than
electrolysis because it is more cost
effective.
11.
12.
13. Three substances are needed to enable to extraction
of iron from its ore. The combined mixture is called the
charge:
Iron ore, haematite - often contains sand with iron
oxide, Fe2O3.
Limestone (calcium carbonate).
Coke - mainly carbon
The charge is placed a giant chimney called a blast
furnace. The blast furnace is around 30 metres high
and lined with fireproof bricks. Hot air is blasted
through the bottom.
The Method
14. •Oxygen in the air reacts with coke to give
carbon dioxide:
C(s) + O 2(g) CO2(g)
•The limestone breaks down to form carbon
dioxide:
CaCO3(s) CO2 (g) + CaO(s)
•Carbon dioxide produced in 1 + 2 react with
more coke to produce carbon monoxide:
CO2(g) + C(s) 2CO(g)
Several reactions take place before the iron is
finally produced...
15. • The carbon monoxide reduces the iron in the
ore to give molten iron:
3CO(g) + Fe2O3(s) 2Fe(l) + 3CO2(g)
• The limestone from 2, reacts with the sand to
form slag (calcium silicate):
CaO(s) + SiO(s) CaSiO3(l)
16. •Both the slag and iron are drained from the bottom of
the furnace.
•The slag is mainly used to build roads.
•The iron whilst molten is poured into moulds and left to
solidify - this is called cast iron and is used to make
railings and storage tanks.
•The rest of the iron is used to make steel.
17. There are three major commercial forms of Iron.
They differ in their carbon content.
1. Cast Iron (or Pig Iron)
It contains 2-5% Carbon along with traces of
other impurities like
Sulphur, Phosphorus, Manganese etc.
2. Wrought Iron
It is the purest form of Iron and contains carbon
to the extent of 0.25%.
3. Steel
It contains 0.5 to 1.5 % of carbon along with
varying amount of other elements.
