OTE Outotec Sintering Technologies Eng Web

7/29/2019 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


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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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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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.


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.

[email protected]

www.outotec.com

Copyright 011 Outotec Oyj. All rights reserved.

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OTE Outotec Sintering Technologies Eng Web