Transcript IRON AND STEEL

IRON AND STEEL IN
EUROPEAN UNION
By:
Rubén Robles
J. Clemente Elices
Ángel Cobo
12-7-2007
GENERAL INFORMATION
Ancient steel.
Woortz steel produced in
India and Sri Lanka from
around 500 year BC was
produced in a wind furnace,
blown by the monsoon
winds. In the 4th century
BC Steel weapons like the
Falcata were produced in
the Iberian peninsula.
Crucible steel was produced
in mery by 9th century AD
GENERAL INFORMATION
STEEL NOW
Iron and steel are important products that are widely used. The
production of crude steel in the European Union stood at 155.3
million tonnes in 1999, equivalent to about 20% of world
GENERAL INFORMATION
The apparent steel consumption per capita in the
EU in 1995 was 367 kg/capita
GEOGRAPHICAL DISTRIBUTION
OF STEEL IN THE EU
The most steelworks
are localice in the
center of europe
Germany is the country
with most steelworks,
Producing 40 millon
tonnes of crude steel in
1996
GEOGRAPHICAL DISTRIBUTION
OF STEEL IN EU
REST OF WORLD (2006) CIFRES
Total productión of crude steel (millon tonnes)
1996
2005
European union (15)
146,565
165,125
European union (25)
169,590
187,337
24,185
33,117
Rest of Europe
C.I.S. (commonwealth of
independent states)
76,880
112,876
North America
124,476
127,631
South América
35,870
45,316
Africa
12,667
17,945
9,169
15,257
288,032
590,661
9,223
8,646
750,090
1138,786
Asia Middle East
Asia
Oceania
World
STRUCTURE OF THE IRON AND STEEL BREF
Sinter plants
Pelletisation plants
Coke oven plants
Blast furnaces
Basic oxygen
steelmaking
Electric arc furnace
steelmaking
BASIC OXYGEN STEELMAKING
Accounting for 60% of the world's total output of
crude steel, the Basic Oxygen Steelmaking process
is the dominant steelmaking technology
The primary raw materials for are 70-80% liquid hot
metal from the blast furnace and the balance is steel
scrap
These are charged into the Basic Oxygen Furnace
(BOF) vessel
Oxygen (99.5% pure) is "blown" into the BOF at
supersonic velocities. It oxidizes the carbon and
silicon contained in the hot metal liberating great
quantities of heat which melts the scrap.
BASIC OXYGEN STEELMAKING
The product is molten
steel.
From here it may
undergo further refining
in a secondary refining
process or be sent
directly to the
continuous caster
where it is solidified
into semifinished
shapes: blooms, billets,
or slabs.
BASIC OXYGEN STEELMAKING
BOF-BAT
Process-integrated measures
PI.1 Energy recovery from the BOF gas
PI.2 Lowering the zinc-content of scrap
PI.3 On-line sampling and analysis of steel
End-of-pipe techniques
EP.1 Primary de-dusting
EP.2 Particulate matter abatement from pig iron pretreatment
EP.3 Secondary de-dusting
EP.4 Dust hot-briquetting and recycling
EP.5 Treatment of wastewater from wet de-dusting
EP.6 Treatment of wastewater from continuous casting
BOF-BAT
PI.1 Energy recovery from the BOF gas
Generally, two systems can be used to recover energy
from the BOF gas:
• Combustion of BOF gas in the converter gas duct and
subsequent recovery of the sensible heat in a waste heat
boiler.
• Suppression of BOF gas combustion and storage of the
BOF gas in a gasholder for subsequent use.
BOF-BAT
PI.2 Lowering the zinc content of scrap
A high zinc content in the blast furnace has an
adverse affect on correct operation. This zinc
mainly originates from the scrap charged into
the basic oxygen furnace. The release of Zn can
fluctuate strongly from one cast to another. The
same problem, but to a lesser extent, applies to
lead (Pb) or cadmium (Cd).
BOF-BAT
PI.3 On-line sampling and steel analysis
Oxygen steelmaking is a batch process. In
order to monitor progress samples are taken
from the steel bath for analysis. It used to be
necessary to interrupt oxygen blowing and tilt
the BOF in order to take the sample. This was a
time consuming process and it increased
emissions from the BOF. In a modern plant
samples are taken on-line during oxygen
blowing by means of a sub-lance.
BOF-BAT
EP.1 Primary de-dusting
During oxygen blowing, BOF gas is
generated.This gas is loaded with a large
amount of particulate matter. The BOF gas is
recovered for use as a fuel. Primary de-dusting
is usually performed by venturi-type scrubbers
(approximately 90% of the plants) or dry
electrostatic precipitators. Prior to the venturi or
the ESP, coarse particulates are usually
removed by means of a deflector
BOF-BAT
EP.2 Particulate matter abatement from
pig iron pre-treatment
BOF-BAT
EP.3 De-dusting of secondary off-gases
Secondary off-gases result from following
operations:
- reladling and deslagging of hot metal
- BOF charging
- tapping of liquid steel and slag from BOF
(converters) and ladles
- secondary metallurgy and tapping operations
- handling of additives
- continuous casting
BOF-BAT
EP.4 Dust hot-briquetting and recycling with
recovery of high Zn concentrated pellets for
external
reuse.
BOF-BAT
EP.5 Treatment of wastewater from wet dedusting
In most oxygen steelmaking plants, scrubbers
are used to reduce emissions to air from the
primary gas flow. This potentially transfers
pollution from air to water so the wastewater
generated is usually recycled and treated before
discharge. The water from the scrubbers mainly
contains suspended solids; Zinc and lead being
the main heavy metals present.
BOF-BAT
EP.6 Treatment of wastewater from
continuous casting.
EMERGING TECHNIQUES-BOF
The following techniques have been
identified as emerging techniques:
- Near net-shape casting and horizontal casting;
- Processing of Zn-rich sludges/dusts;
- New reagents in the desulphurisation process;
- Application of foaming techniques in pig iron pretreatment and steel refining;
- Replacing air above the hot metal by inert gases
(CO2, N2).
ELECTRIC STEELMAKING
ELECTRIC STEELMAKING
The direct smelting of iron-containing materials,
such as scrap is usually performed in electric arc
furnaces (EAF) which play an important and
increasing role in modern steel works concepts
Today the percentage of electric arc furnace
steel of the overall steel production in the EU are
35.3 %.
In Italy and Spain the production of electric arc
furnace steel higher than steel production via the
blast furnace-basic oxygen furnace route.
ELECTRIC STEELMAKING
For the production of carbon steel and low/hight
alloyed steels, following main operations are
performed:
Raw material handling and storage
Furnace charging with/without scrap preheating
EAF scrap melting
Steel and slag tapping
Ladle furnace treatments for quality adjustment
Slag handling
Continuous casting
ELECTRIC STEELMAKING-BAT
Process-integrated measures:
PI.1 EAF process optimisation
PI.2 Scrap preheating
PI.3 Closed loop water cooling system
End-of-pipe techniques:
EP.1 Advanced emission collection systems
EP.2 Efficient post-combustion in combination with
advanced off gas treatment
EP.3 Injection of lignite coke powder for off gas treatment
EP.4 Recycling of EAF slags
EP.5 Recycling of EAF dusts
ELECTRIC STEELMAKING-BAT
PI.1 EAF process optimisation
ELECTRIC STEELMAKING-BAT
PI.2 Scrap preheating
ELECTRIC STEELMAKING-BAT
PI. 3 Closed loop water cooling system
The most relevant use of water considered here
is the water used for the cooling of the elements
of the furnace. Additionally, some water may be
used for the cooling of waste gas or in the
secondary metallurgy section.
ELECTRIC STEELMAKING-BAT
EP.1 Advanced emission collection systems
The primary and secondary emissions to air are
of high relevance. The available abatement
techniques should be fed with the raw emissions
as complete as possible. Thus the collection of
the emissions is important. The combination of
4th hole (in case of three electrodes)
respectively of 2nd hole (in case of one
electrode) direct extraction with hood systems
(or furnace enclosure) or total building
evacuation are the most favorite systems.
ELECTRIC STEELMAKING-BAT
EP.2 Efficient post-combustion in
combination with advanced off gas treatment
Post combustion in the furnace is developed to
use a maximum of chemical energy of the CO in
the furnace and to improve the energy balance,
but CO and H2 are never completely oxidised in
the furnace; for this reason, it needs post
combustion.
ELECTRIC STEELMAKING-BAT
EP.3 Injection of lignite coke powder for
off gas treatment
In order to reduce organic micropollutants in the
total off gas (primary and secondary emissions),
especially PCDD/F lignite coke powder can be
dosed to the duct beforem the bag filters.
ELECTRIC STEELMAKING-BAT
EP.4 EAF slag recycling
EAF slag can be regarded as an artificial rock,
similar to natural rock, consisting of iron-oxides
(FeO), lime (CaO), silicium-oxide (SiO2), and
other oxides (MgO, Al2O3, MnO) EAF slags are
characterised by high strength, good weathering
resistance, and also high resistance against
polishing. They also have properties, that make
them suitable for use in hydraulic engineering.
ELECTRIC STEELMAKING-BAT
EP.5 EAF dust recyling
There are two method of dust recycling:
• Recycling of precipitated dusts
• Zinc recovery and removal of heavy metals
EMERGING TECHNIQUES-EAF
Scrap sorting
New furnace concepts
• Comelt EAF
State of Development / Realisation
• Contiarc furnace
FURTHER READING
www.worldsteel.com
www.aceralia.es
www.wikipedia.com