Alternative to blast furnace

1. Alternatives to the Blast
furnace
COREX ( Smelting Reduction)
Harmfree Muchada
Kudzwai mafema

2. By definition:
COREX is the first and the only
commercially established smelting-
reduction process, as an alternative
route to blast furnace, based on non-
coking coal.

3. Essential Features:
COREX consists of two reactors,
the reduction shaft and the melter-
gasifier. The reduction shaft is
placed above the melter-gasifier and
reduced iron bearing material
descends by gravity. The volume of
the reduction shaft and the melter-
gasifier is about 600 m3 and 2200
m3 respectively.

4. Schematic diagram of a COREX plant

5. How it Works:
It contains a melter-gasifier with a reduction shaft
to produce a liquid product that is very similar to
blast furnace hot metal.
Lump iron ore and/or pellets and addictives are
charged at the top of a reduction shaft.
Reducing gas from the melter-gasifier is injected
into the lower part to reduce the iron ore to sponge
iron (DRI).
The addictives ensure that adequate slag basicity
and sulphur removal from the hot metal in the
melter-gasifier is achieved.

6. How it Works (cont):
The hot D.R.I (metallization 80-95%) and calcined
addictives are then transferred into the melter-gasifier by
screw conveyor.
Lump coal (6-50mm) is fed separately through the dome
where it falls onto the char bed above the hearth.
In the hot, reducing atmosphere (about 1000 degrees), the
coal is dried and devolatilized to char.
The tars and other volatile matter from the coal are crashed
and oxidized to mainly CO and hydrogen.

7. Chemical Reactions
3Fe2O3 + CO= 2Fe3O4+ CO2 eq. (1)
Fe3O4+ CO = 3Feo +CO2 eq. (2)
FeO+ CO = Fe + CO2 eq. (3)
The carbon monoxide required for reduction:
C+CO2 =2CO

8. The Final Product:
The DRI passes through the char
bed where it is finally reduced and
melted, creating a pod of slag and
metal both are discharged by
conventional tapping procedures.

9. Iron ore characteristics

10. Typical Corex hot metal and slag
Hot metal analysis
Constituent C Si S P Mn
% 4.5 – 5.0 0.4 – 0.6 0.015 – 0.035 0.07 – 0.12 0.06 – 0.08
Slag analysis
Constituent CaO MgO SiO2 Al2O3 FeO TiO2 S
% 35-37 12.8-13.5 30-32 15-16 0.25-0.60 0.25-0.65 1.10-1.26

11. Advantages of Corex Iron reduction
process
Product quality – hot metal quality suitable
for all steel applications.
Economic benefit – low investment and
operational costs due to the elimination of
coking and sinter plants.
Ecologic benefit – lowest process-related
emission rates

12. Cont.
Resource preserving – use of a wide variety of iron
ores and especially non-coking coals.
Beneficial by-products – generation of a highly
valuable export gas for various purposes (electric power
generation, DRI production, or natural gas substitution).
Lower production costs -because coking and sinter
plants are not needed with Corex, production and
investment cost are reduced substantially.
Lower dependency on the local power and gas supply
(Anon., 2015)

13. Similarities Between the Corex Process and
Blast furnace
Both of the processes have iron ore as one of the
raw materials.

14. How it differs from the Blast Furnace
 the Corex process doesn’t need sinter to be
part of the smelting components.
The Corex process make use of non-coking
coal instead of coal.
 the possible use of fine ores and pellets

15. THANK YOU !!!!!