Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
05. Carbo - Metalothermic
Zulfiadi Zulhan
Taufiq Hidayat
Imam Santoso
Department of Metallurgical Engineering
Faculty of Mining and Petroleum Engineering
Institut Teknologi Bandung
INDONESIA
Pyrometallurgy (MG-3111)
5th Semester – 2021/2022
Teknik MetalurgiTeknik MetalurgiTeknik Metalurgi
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
NO TALKING
NO SLEEPING
NO MOBILE PHONE
http://www.longestlife.com
https://www.pinterest.com
https://www.pinterest.se
http://clipart-library.com
https://www.dreamstime.com
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Course Content
1. Introduction
2. Refractory
3. Slag
4. Material Preparation: Aglomeration, Drying, Calcination, Roasting
5. Carbo- / Aluminothermic (Metalothermic)
6. Smelting, Refining
7. Pyrometallurgy of Copper Production I
8. Pyrometallurgy of Copper Production II
9. Mid Exam
10. Pyrometallurgy of Tin Production
11. Pyrometallurgy of Nickel Production(Nickel Matte, FeNi)
12. Pyrometallurgy of Zinc and Lead Productions
13. Production of Ferro Alloy I (FeMn)
14. Production of Ferro Alloy II (FeCr, FeSi)
15. Group Presentation (FeNb, FeMo, FeTi, FeV, FeTa, FeW, CaSi, CaC2 etc.)
16. Final Exam
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Reduction of Metal Oxides
A large number of metals are produced from oxide raw materials, for
example iron, manganese, chromium, tin, nickel. In case of lead and zinc,
sulfide ores are first roasted to give oxides which are subsequently reduced
to metal. Sulfide ores can be converted directly to matte or to metal using
“flash smelting technology”
Other oxides are decomposed by means of a reducing agent (carbon,
carbon monoxide, hydrogen, and metals which has higher affinity for
oxygen (metallothermic). C, CO and H2 are industrial importance and
economic reducing agent
Only oxide of more noble metals can be converted to metal by simple
thermal decomposition:
Silver oxide decomposes at T>200oC → 2Ag2O = 4 Ag + O2
PtO decompose at T>500oC → 2PtO = 2 Pt + O2
PdO decompose at T>900oC → 2PdO = 2 Pd + O2
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Metal Oxide Reduction by C and CO
Reaction of metal oxides with carbon monoxide:
MeO + CO = Me + CO2 (indirect reaction)
If solid carbon is present in the reaction mixture:
MeO + CO = Me + CO2
CO2 + C = 2 CO (Boudouard reaction)
+
MeO + C = Me + CO (direct reaction)
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Lo
g p
CO
2/ p
CO
Indirect Reaction:
MeO + CO = Me + CO2
For reduction of metal oxide with
CO (absence of solid carbon), the
curve for Boudouard reaction can
be disregarded.
Cu2O, PbO and NiO can be
reduced at CO2/CO ratio between
102 and 105 (very small
concentration of CO in the gas).
If pure CO is used, practically all
CO will be converted into CO2
before the reaction stops.
For reduction of MnO and SiO2,
requires pure CO gas (free of
CO2). Reaction will stop as soon
as CO2 is formed. In other word,
these reduction is impossible in
practice.
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Lo
g p
CO
2/ p
CO
In the presence of solid carbon
(Direct Reduction), carbon reacts
with CO2. Boudouard line is
considered.
SnO2 is reduced by C at T > 610oC
Fe3O4 can be reduced to FeO at
T > 650oC
FeO to Fe at T > 700oC
MnO is reduced by C: T> 1400oC
SiO2 is reduced by C: T> 1600oC
At higher temperature Al2O3 and
MgO can be reduced by carbon.
Reduction of metal oxides by solid
carbon is called Carbothermic
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Thermodynamic of Iron Oxide Reduction (CO-CO2)
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000 1200 1400
Temperature [°C]
CO
/ (
CO
+ C
O2)
[%]
Fe3O4
FeO
Fe
Ptot = 0.2 atm
Ptot = 1.0 atm
Ptot = 5.0 atm
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
SiO2 can be reduced by carbon
at temperature more than
~1750oC.
SiO2 + 2C = Si + 2CO
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Al2O3 can be reduced by
carbon at temperature more
than 2000oC.
This temperature can be
achieved in electric arc furnace.
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Aluminum Carbothermic Technology (ACT)
(in development phase)
Advantage of ACT:
- Energy consumption of 10 kWh/kg Al (versus over 13 kWh/kg Al for Hall-
Heroult)
- capital costs as low as $1250 per MTY (versus 4,000 per MTY for Hall-
Heroult)
- operating cost reductions of over 10 %,and
- up to 37 % reduction in CO2 emissions for fossil-fuel power plants.
Crbothermic Advanced Reactor Process is a multi-stage system in which a
molten slag bath containing alumina and carbon is reacted to produce
aluminum carbide in a low temperature stage. The resulting alumina –
aluminum carbide slag then flows into a high temperature stage where the
aluminum carbide is reacted with the alumina to produce aluminum metal.
The aluminum is less dense than the slag and accumulates as a layer
floating on the slag.
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Aluminium Carbothermic Technology
The overall reaction for carbothermic aluminum production can be written
Al2O3 + 3 C = 2 Al + 3 CO
25 25 2000 600 °C
Al2O3 3 C
Al2O3 + 3 C = 2 Al + 3 CO, H298 = ... T ref.= 298 K
2 Al
2273 K
3 CO
873 K
Energy consumption ~ 7.9 kWh/kg Al
Energy efficiency around 80%
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Aluminium Carbothermic Technology
If Al2O3 and C is heated at atmospheric pressure, a complex product is
formed.
Al2O3 and Al4C3 can occur as separate phases, or they can combine to
make a liquid Al2O3-Al4C3 slag.
Al4C3 is stable only up to 2150°C; above it decomposes to Al and C. The
Al phase always contains some C.
Stage 1: 2 Al2O3 + 9C = Al4C3 + 6 CO
Stage 2: Al4C3 + Al2O3 = 6 Al + 3 CO
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Flow chart of ACT concept
Stage 1: 2 Al2O3 + 9C = Al4C3 + 6 CO
Stage 2: Al4C3 + Al2O3 = 6 Al + 3 CO
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Metal Oxide Reduction
with Hydrogen
Pure hydrogen is less industrial
importance reduction than
carbon and carbon monoxide
(may be used under special
condition).
Very often the reduction is
carried out with mixtures of CO
and H2.
Natural gas is used as source of
this reduction gas.
Product of reduction with hydrogen
is metals.
By reduction with carbon, carbide
might be formed
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Thermodynamic of Iron Oxide Reduction (H2-H2O)
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000 1200 1400
Temperature [°C]
H2 / (
H2 +
H2O
) [%
]
Fe3O4
FeO
Fe
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Thermodynamic of Iron Oxide Reduction
(CO-CO2-H2-H2O)
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000 1200 1400
Temperature [°C]
CO
/ (
CO
+ C
O2)
[%]
or
H2 / (
H2 +
H2O
) [%
]
Ptot = 0.2 atm
Ptot = 1.0 atm
Ptot = 5.0 atm
Fe3O4
FeO
Fe
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Metallothermic
Metal which has higher oxygen affinity is used as reducing agents.
Silicon, aluminium and also magnesium can be used as reduction agents
in order to produce metals of low carbon content.
Metallothermic reactions are usually carried out between solid or molten
reactants to give molten products.
Example:
2 Cr2O3 + 3Si = 4 Cr + 3SiO2 (silicothermic)
Cr2O3 +2 Al = 2Cr + Al2O3 (aluminothermic)
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Silicothermic Ferrochromium Production
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Aluminothermic
FeTi, FeV, FeNb and Cr(99%)
can be produced by
aluminothermic.
Reaction can be done
autogeneously, i.e. by igniting
a mixture of cold oxide with
aluminium powder.
Compare to carbothermic:
- Slag volume of metallothermic
is large, high loss of valuable
metal in slag.
- Not possible to produce metal
completely free of silicon and
aluminum
Zulfiadi Zulhan/Taufiq Hidayat/Imam Santoso 2021 MG-3111 Pyrometallurgy
Terima kasih!Program Studi Teknik Metalurgi
Fakultas Teknik Pertambangan dan Perminyakan
Institut Teknologi Bandung
Jl. Ganesa No. 10
Bandung 40132
INDONESIA
www.metallurgy.itb.ac.id
Dr.-Ing. Zulfiadi Zulhan, ST., MT.
Taufiq Hidayat, ST., M.Phil., Ph.D.
D.Sc. (Tech.) Imam Santoso, ST., M.Phil