Bessemer Process The Bessemer Converter Working Of The Converter

1. Manufacture of
steel: Bessemer
process
Saniya khwaja
S.Y BSc. BEd
Chemistry
BSC 322

2.  Before the Bessemer process, steel
was too costly to make in great
quantities .
 Before the Bessemer process ,steel
could only be made through
Benjamin Huntsman’s crucible
method.
 The primary metal of industrial
revolution until then was iron .
 Wrought iron has a low carbon
content , which makes it softer and
more malleable , while pig and cast
iron have a high carbon content and
are brittle .

3. Bessemer Process
 Henry Bessemer
 Patented in 1855
 First inexpensive industrial process for
mass production of steel from moten pig
iron
 Key principle
 -removal of impurities like manganese,
silicon and carbon by oxidation
 Air blown through the molten Iron

4. The process takes place in a steel container called a
Bessemer converter . Molten pig iron is poured into
the converter as air is blown through multiple holes
perforating the bottom .
The air does not cool the iron , instead , it oxidizes
the molten mass and raises the temperature even
further . This removes the impurities and rapidly
reduces the carbon content to its desired level.

5. The Bessemer Converter
 The Bessemer converter is
wide at bottom and narrow
at top as shown in fig. 11-1.
It is mounted on two
horizontal trunnions so that
it can be tilted or rotated at
suitable angle.
 The tuyeres are provided
at the bottom to allow
passage of air from the air
duct to the pig –iron.

6. Working Of The Bessemer
Converter

7. Working Of The Converter
 (i) The converter is tilted and it is
charged with molten pig-iron from
cupola furnace or sometimes even
directly from the blast furnace.
 (ii) The converter is brought in an
upright position and a blast of hot air
is forced through the tuyeres.
 (iii) The air passes through the
molten pig-iron. It oxidizes impurities
of pig-iron and a brilliant reddish-
yellow flame is seen at the nose of
converter.

8.  (iv) The flame is accompanied by a loud roaring sound and
within 10 to 15 minutes or so, all the impurities of pig-iron are
oxidized. The order of oxidation of various impurities is silicon,
carbon, manganese, sulphur and phosphorus.
 (v) When the intensity of flame has considerably reduced, the
blast is shut off and the required amount of suitable material
such as ferro-manganese, spiege-leisen, etc. is added to make
steel of desired quality.

9.  (vi) The blast of air is started for a few minutes. The
converter is then tilted in discharge position and the molten
metal is carried into ladles or containers.
 (vii) The molten metal is poured into large rectangular
moulds for solidification. Such solidified mass is known as
the ingot. These ingots are then further treated to form steel
of commercial pattern.

10. Thank You!