ote outotec sintering technologies eng web
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Outotec Sintering technologies
40% of the worlds sintering
Iron ore sintering has stood at the heart o the errous
metallurgical processes or over hal a century. Outotec
has solid experience in agglomeration o ine-grained
iron ores. We have built over 400 sintering plants with
capacities ranging rom 600 to 0,000 tons per day since
190. Today, 40% o the worlds sinter is produced by
our technology. Besides iron ores, it can also be applied
or sintering o manganese ore ines.
Over the years, we have developed a number o
innovative technologies that increase the perormance
and reduce the capital and operating costs. Long-
term research and testing with raw materials o
dierent origins and process parameters, coupled
with continuous development and improvements in
mechanical design and process automation have made
us an unparalleled technology partner.
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002 Sintering technologies
Outotec Sintering Process
Outotec sintering process begins with the preparation
o raw mix rom iron ores, uxes, in-plant dust and
spillage fnes, solid uel and return fnes. These
materials are mixed and granulated in one or more
stages. Water is added in order to assist the raw mix
in obtaining optimum permeability or lower electricity
consumption, maintained by conveying the raw mix
careully onto the sinter machine. Its surace is then
ignited, air being induced through the ignited layer and
sintering proceeding in the vertical direction in the
sinter strands material bed. Subsequently, the sinter
is cooled, usually in a separate sinter cooler, located at
the sinter machines discharge outlet.
The cooled sinter is crushed to a pre-determined
maximum particle size. Undersized sinter that is not
suitable or the blast urnace is recycled to the return
fnes bin. A certain quantity, usually 100 mm, is
screened out and recirculated to the sinter machine,
where it serves as a hearth layer, protecting the grate
bars o the pallets during the sintering process.
The product obtained rom the process is a blast
urnace eed o superior quality.
Tata Iron and Steel Co., India, has already three Outotec sintering plants in operation.
Why sinter?
Sintering is the agglomeration o fne-grained iron ores
or blast urnace burden preparation. Manganese ores
can also be sintered beore smelting in the electric
arc urnace. Sintering produces a eed o extremely
consistent quality in terms o its:
n Chemical composition
n Grain size distribution
n Reducibility
n Sinter strength
Environmental safety
Outotec sinter plants are designed to meet the
most stringent environmental regulations.
For effective dust collection, electrostatic
precipitators and/or bag filters dedust the
sinter waste gas and air from the plant
dedusting system. We provide processes for
limiting dioxin, SOx and NOx emissions, while
incorporating noise attenuation equipment to
meet local regulations.
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Sintering technologies 003
Energy savings and reduced emissions
What is more, CO and pollutants like SOx, NOx, dustand dioxins/urans are passed through the sinter layer
together with the recirculated gas. While CO is post-
combusted, substantially saving on solid uel, the
pollutants are partially retained in the sinter layer and/
or thermically decomposed.
In integrated steel plants about 75% o the CO
emissions are generated in the blast urnace and
about 1% in the sintering process. When ollowing
the international CO policy, the Kyoto protocol, and
as there is only a minimum technical margin or CO
reduction measures in the blast urnace, EOS brings
signifcant benefts or all steel plant operators.
Typical ow sheet o a sinter plant with EOS system.
Bleed in
Recirculationgas system
Fresh airsupply system
Outotec EOS Emission optimized sintering for lower
costs
Iron ore sintering creates substantial o-gas volumes,
and treating these in order to meet increasingly
stringent environmental standards is expensive. That
is why we have developed the emission optimized
sintering process. EOS uses recycling technology
to reduce o-gas volumes by 40 to 50%, resulting in
smaller secondary gas treatment systems.
This means:
n Lower capital investment
n Reduced operating costs
Conventional sintering uses ambient air to transport
heat within the sinter bed, requiring a high air ow
rate. However, EOS takes advantage o the act that
only a part o the oxygen in the air is consumed or coke
combustion. Thereore a part stream o the o-gas is
recycled via the hood, enriched with ambient air to an
oxygen content o 1314% and used as intake process
air. This reduces o-gas volumes by about 4050%
without aecting the sintering process.
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Each pallet comprises
n A cast pallet body, as a single unit or in
three pieces
n Exchangeable front plates
n Four roller sets, each set containing one
running roller and one pressure roller,
both arranged on the same shaft
n Grate bars made from high alloyed cast steel
n Side walls of cast material
n Insulating sections to protect the pallet body
004 Sintering technologies
High intensity mixing and nodulizing
Mixing and granulation is perormed in two separate
high intensity mixers, which have the advantage o
minor investment costs and space requirements,
combined with an excellent mixing and granulation
eect, especially or fne grained ores.
The required amount o process water will be added
to the two mixers in predetermined ratios by means o
spray nozzles, in order to adjust the optimum moisture/
permeability o the eed mix.
Ignition furnace for optimum
maintenance and operation
Outotec ignition urnaces consist o standardized
segments, each with straight reractory lined vertical
side walls and a laterally-arranged special combustion
chamber on each side. This design oers the optimum
solution in terms o maintenance and operation:
n Uniorm ignition
n Highly exible operation in response to uctuations
in material bed permeability
n Possibility o operation with a high rate o excess air
n High saety standards
Lurgi traveling grate
Our solution or sinter machine is a Lurgi traveling
grate consisting o an endless chain o pallets. Its
eeding station ensures a continuous supply o hearth
layer and eed mix to the sinter machine. Both the
eed bins or hearth layer and or eed mix are level
controlled. Furthermore, the hearth layer bin is
equipped with an adjustable gate, providing a hearth
layer o a predetermined height.
The eed mix hopper outlet is equipped with motorized
gates or adjusting the amount o material to be
discharged via a variable speed roll eeder. Ultrasonic
sensors control the bed height level o the individually
motorized gates.
The roll eeder discharges the material onto a
segregation plate. This is an inclined plate across the
pallet width. Its inclination and positioning in relation
to the material ow rom the roll eeder is adjustable or:
n Improved eed mix permeability,lowering
power consumption
n Optimum segregation o fne and
coarse particles
n Optimum ormation o the material layer on the pallets
The variable speed roll eeder is mounted on a separate
support with rails and wheels to permit roll-in and roll-
out or maintenance purposes.
Longer lasting pallets
Since our pallets only come into contact with one
another on the horizontal section o the upper and lower
track, wear is minimized. Durability is also enhanced
through the separation o each pallet rom the chain by
a liting and lowering sprocket at each station.
Proprietary equipment
for control, quality,
economy and safety
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Sintering technologies 005
Discharge station for long service life
The sinter strand discharges the sinter onto a crash
deck, specially designed and equipped with wear-
resistant material, rom where it slides into a spikedroll crusher whose crushing arms grind it to a
maximum size o 00 mm. A movable grizzly carrier is
also eatured.
Direct charging to cooler improves cooling efficiency
and reduces emissions
The material discharged rom the sinter machine
enters a chute with a round opening. A concave material
layer is built up on the sides o the chute. While passing
through the opening, the entire raction is mixed.
This mixed material alls onto a radially adjustable
saddle, where the material is re-segregated, the coarse
material being deposited on the rear part o the lower
chute section while the fne material is deposited in the
center. As the cooler moves, the material accumulates
on it to orm a sloping material layer, whose height is
determined by the inner angle o repose o the sinter.
Upon the withdrawal o the material, a core ow develops,
large lumps rom the rear settling on the bottom o the
cooler, fne material in the middle and medium sized on
top.
Efficient sinter cooling
While hot sinter is best cooled in a separate cooler,
on-strand cooling can be applied in particular
appli-cations. Our cooler eatures all o the essential
attributes:
n Annular arrangement o troughs
n Cooling air pressed through the sintern A bed height o 1.4 to 1.6 m,
minimizing the cooling air volume
n Horizontal movement o the cooler trough, with the
trough bottoms ollowing a dip rail at the discharge
station
The cooler trough wheels run on a circular rail
supported by a concrete sub-base, which also serves
as a wind channel or cooling air. While the cooler is
driven by riction drive units via a segmented riction
ring, cooling air ans are arranged outside the cooler.
Spillage collecting plates underneath each cooler
trough bottom plate retain all sinter spillage and
discharge it to the collecting hopper. Special seal bars,
individually supported on at spring plates, minimizecooling air leakages.
Height-adjustable wheels provide equalized, uniorm
wheel loads, while temperature optimized side wall
clamping allows or thermo-expansions without
stressing the cooler.
Natural segregation with the maintenance-free
cascade classifier
Outotec's new cascade classifer, separating coarserom fne size iron ore sinter stream material, replaces
the scalping screen in ront o double roll crushers. It
unctions based on:
n Natural segregation by dropping or pouring material
n Adjustable saddles (adjusted once during
start-up phase), guaranteeing the removal o
inadmissible coarse material rom the separated fnes
The cascade classifer is almost maintenance-ree,
since it runs on stone box type saddles which do not
touch the side walls. Coarse particles separated at the
saddle ront side are ed into the cold sinter double roll
crusher, while fne material separ ated at the saddle ar
side by-passes the crusher and is mixed again with the
crushed material underneath.
Energy savings together with
reduced emissions:
n Optimum permeability of the
sinter layer on the cooler
n Optimal use of the cooling air
n Minimum spillage since sinter fines are
held off the trough bottom
n Minimum dust emission since sinter fines
are covered by the middle size sinter
fraction, acting as a filtration layer
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006 Sintering technologies
State-of-the-art control systems
Sinter plant in Middlesbrough, U.K.
These enable extensive supervisory control unctions
using standard distributed or open control systems
(DCS/OCS).
Such an architecture supports the addition o
an operational layer above DCS/OCS or process
management (level 3) including monitoring, analyzing,
optimizing, simulating and pre-tuning level
controllers (process management) based on a dynamic
computer sinter model.
Flexibility brings extra benefits
Our sinter plants are designed to cater or uctuating
production requirements. To enable high production
rates, some plants are designed or a specifc output
o up to 45 t/4 h/m. For lower rates, plants can be
operated with maximum energy savings and superior
sinter quality.
Outotec sinter plant control systems include:
n Return fnes balance control
n Material mixture computing and control with
individual moisture control
n Burn through-point control/sinter capacity control
n Ignition urnace control with permeability
measurement
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R&D facilities providing economy and
innovative technology
Outotecs long research pedigree, based on our own
acilities in Frankurt, Germany, orms the basis or
the successul design and construction o sinter plants.
While test series yield specifc data or the optimum
technical and economical design o commercial plants,
pot tests determine the key ore mix parameters (spe-
cifc sinter output as a unction o the applied suction
and required sinter quality) or use together with the
ux and solid uel. These parameters orm the basis osinter plant design. Our ull range o R&D acilities test
sinter properties to meet international standards such
as ISO, ASTM, JIS and DIN.
Traveling grate dimensions
n 36600 m reaction area
n 5 m machine width
Capacity
n 0.156.5 million tpy in single units
n Availability 330345 days/year
n Specifc production rates up to 45 t/4 h/m
Consumption figures (per ton of product sinter)
n Solid and gaseous uel: 1501400 MJ
n Electrical energy: 83 KWh
n Process water: 0.030.05 m3
Operational manpower (4-shift basis):
n 160 men per day
Process parameters
n Basicity CaO/SiO2: 1..9
n Bed height: 500730 mm
n Suction: 130190 mbar
n Return fnes rate: 185%
Product qualities
n ISO-strength (+ 6.3 mm) 7580%n RDI (-3 mm) 83%
n FeO 58%
Sinter plant modernization
a made-to-fit process
Our solutions are not only valid or new plants but also
revamps, retrofts and capacity increases. To improve
the efciency o existing plants we provide a number
o alternatives, ranging rom individual equipment
replacement to extensive plant rehabilitations, tailored
to each customers specifc needs.
Sintering technologies 007
Facts about Outotec
sinter plants
Plant modernization can include:
n Replacement of obsolete equipment
n Upgrading of sinter plants
n Construction of plant units and new sinter
plants with maximum leverage of the
existing infrastructure
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Finland,
December2011.
Outotec develops and provides technology solutions for the sustainable use of Earths natural resources.
As the g lobal leader i n m iner als a nd metals proce ss ing technology, Outotec h as developed o ver d ecades
severa l breakthrough technologies . The company also offers innovative solutions f or the chemical
industry, industrial water treatment and the utilization of alternative energy sources. Outotec shares are
listed on the NASDAQ OMX Helsinki.
www.outotec.com
Copyright 011 Outotec Oyj. All rights reserved.