Co2-Emissions and the Ferroalloys Industry

The Proceedings of INFACON 8

Tor Lindstad

SINTEF Materials Technology Alfred Getz vei 2B, N-7034 Trondheim, Norway

Abstract Thermodynamfcal Premises

COrcmissions connected ·with :. the production of ferrosilicon, Metal oxides are the only raw materials for ferroalloys, except that silicon-metal , silicomanganese and ferromanganese are discussed. scrap iron is often used to supply the iron part. The Gibbs energy The specific COz-emission is given for different ways for needed to decompose the oxides to metal and oxygen are so high generating electric power; hydro-/nuclear, natural gas, coal and a that only solid carbon or electrolysis can be used to break the European mix of energy sources. COremissions connected to coke binding between the metal atom and oxygen, as the case is for production are included. Otherwise the paper has not taken into aluminium and silicon. For manganese and chromium oxides, part account the contribution to COz-emissions from mining raw of the oxygen (in the higher oxides) can also react with carbon material, or transport of raw materials and products. The use of bio monoxide or hydrogen. carbon as a source for carbon is discussed. Present and possible contributions to the global C0 2-balance by using by-products and Breaking the metal-oxygen binding by electrolysis is the process recovering energy from off-gases are discussed. used for production of aluminium, but is also theoretically possible for silicon and is used for the production of manganese metal. We will take a closer look on electrolysis as a possibility to reduce C0 2 Introduction emissions.

In the sixties, both the public and politicians became more aware of C02-emissions from the ferroalloys industry. Status environmental issues. New laws were passed in many countries, new regulatory agencies were established and public control of The sources for carbon dioxide - emissions are the reduction emissions and effluents were increased. Since then solving materials (coal and coke) and the power generation (if coal, oil or

environm~ntulproblems caused by our industry has been an gas is used). If coke is used, we should also include the emission of essential part of the rnerallurgist's work. One example is the si lica C02 from the coking process. Carbon dioxide generated from fumes evolved in production of forrosilicon and silicon-metal. After renewable carbon sources like charcoal is not included. The amount some years of research a process using bag filters to collect the of em issions depends on the processes and the technical standards. silica dust was developed. The large quantities of dust collected The numbers chosen for efficiency of the power plant, electric represented however a major disposal problem. A heavy research energy and carbon consumption per !onne ferroalloy are open for was started in the seventies to find applications for this waste discussion. The numbers in this paper are believed to represent product [ l ]. As we know many applications have been found, the good efficiencies. main one being the use as an additive to cement. To collect the silica dust in the off-gas it is necessary to cool the gas. This gives Power generation us the opportunity to recover huge amounts of energy, which directly has relation to the C0 2-problem. Table I. Power generation Energy source Process Thermal C0 2 - emissions We might say that until the last S years the industry's main efficiency, % kg C02/kWh environmental challenges have been to remove local and regional Natural gas Combined cycle so 0,40 pollution, dispose of waste products and use energy and other raw Coal Stearn turbine 33 0,98 materials in a reasonable way. The focus on greenhouse gases, C0 2 UCPTE-mix*) 0,40 in particular, changes dramatically the conditions for the ferroalloys Nuclear 0 industry.In this paper we will try to take a closer look on how the Hydroelectric 0 indu,iry can contribute, directly or indirectly to reduce C0 2 - crnis:~ions. *)UCPTE is abbrevi.ation for " Union pour la co-ordination de la production et du transport de electricite". The union consists of Belgium, Germany, France, Greece, Italy, Ex-Yugoslavia, Luxembourg, The Netherlands, Portugal, Switzerland and Spain. UCPTE-mix is 36.2 % nuclear power, l 5.2 % hydroelectric power, 9.5 % from gas, 9.6 % from oil and 29 % from coal [JO].

-87 - r The Proceedings of INFACON 8

18000 Coke production 16000

~14000 A typical coke for ferroalloys production contains 90 % C (78 % 'ii fix C). Assuming the content of volatiles in the coals to be 35 % ~ 12000 • Hydro-/Nuclear and in the coke to 12 % we have calculated the C0 2 - emissions ti!! 10000 • Natural gas from production of coke to be 1,0 kg C0 2 per kg coke. c Coal ~8000 ;:;. Ill UCPTE-mlx 0 6000 Ferroalloys production u .. 4oo6" ...: The relative amount of coal or coke used will vary from plant tc 2000 plant. If we, however, include the carbon dioxide emissions from

coke production, the specific C0 2 -emissions will be fairly constant FeSl 75 Si-metal SiMn FeMn for each type of ferroalloy, when good efficiencies are presumed for Ferroalloy all. This way of thinking will be correct on a global base, but is difficult when national quotas for emissions are on the agenda.

Figure 1 Total C0 2-emissions Table 2. COr emissions per tonne ferroalloy from electric furnace, including coke production 100,00

Ferroalloy From reduction From electrodes, From ore and Total 90,00 materials, kg C0 kgC0 flux, kg C0 2 2 2 kgC0 2 80,00 F<0Si75 4200 180 4380 70,00 Si-metal 4100 450 4550 60,00 • Hydro-/Nuclear Si Mn 1800 100 150 2050 • Natural gas- % 50,00 FeMn 1800 50 150 2000 0 Coal 40,00 Cl UCPTE-mix To evaluate the total carbon dioxide emissions caused by ferroalloy 30,00 production we add the emissions caused by power generation 20,00 (Table 3) times the power consumption, to the emissions from the 10,00

furnace including the coking process (Table 2) and get Table 4. 0,00 FeSi 75 Si-metal SIMn Fe Mn Ferroalloy The figures in Table 4 are visualised in Fig. 1, where the total COr emissions are plotted. ', Figure 2 -emissions as % of emissions with coal-power In Fig. 2 we have compared the different ways for power generation C0 2 by plotting the total C0 2 - emissions relative to the total emissions where coal is used for power generation (100 %),

Table 3. COi-emissions from the generated power used per tonne ferroalloy,

Ferroalloy Electric energy Electric power generated by: consumption kWh Hydro-/Nuclear Natural gas Coal UCPTE-mix FeSi 75 8800 0 3520 862 3520 Si-metal 12500 0 5000 12250 5000 SiMn 4500 0 1800 4410 1800 FeMn 2700 0 1080 2646 1080

Table 4, Total COremissions per tonne ferroalloy

Ferroalloy Electric energy Electric power generated by: consumption kWh Hydro-/Nuclear Natural gas Coal UCPTE-mix FeSi 75 8800 4380 7900 13004 7900 Si-metal 12500 4550 9550 16800 9550 SiMn 4500 2050 3850 6460 3850 FeMn 2700 2000 3130 4646 3130

-88- r The Proceedings of INFACON 8

Methods or ways to reduce C02-emissions manganese is low, of the order of 65 %. Since rather high cell voltages are used, about 5 V, the energy consumption is so high as In this discussion we will include credits the industry should have, 8.5 kWh/kg [2]. The costs for electrolytic manganese are if our industry's efforts to recover energy or by-products contributes substantially higher than for manganese in ferromanganese. to a reduction of C0 2 - emissions in other areas of activity. According to Metal Bulletin [3], the prices on June 12/13 1997 were:. I. More efficient production will of course contribute to a reduction, connected to both the use of less carbon and less Table 5. Prices for manganese in electrolytic manganese and electrical energy. Strong economic incentives support this trend, ferro manganese and are not necessary to comment further. In ferrosilicon production the typical electric energy consumption has been %Mn %C $/tonne $/tonne Mn reduced from 9800 kWh per tonne in 1977 to 8800 kWh per tonne Electrolytic manganese 99.7 1280-1380 1284-1384 in 1997. Ferromanganese standard 78 7.5 480- 500 615- 640 Ferromanganese medium C 80 <1.5 947- 991 1184-1238 2. Electrolysis is a possibility, but much more electrical energy is needed than in the submerged arc furnace. How the electricity is These differences in prices tell us why ferromanganese and not produced is important. manganese metal is used for alloying steel. At least that is the case when standard ferromangancse can be used.The next question is: 3. Bio-carbon. It is accepted that using carbon from natural sources Will a transition from ferromanganese to electrolytic manganese does not contribute to the greenhouse effect, because carbon give a reduction in C02 -emissions? The answer to this question dioxide formed by the oxidation of endogenous carbon are depends on the way the electricity is generated.The electric energy assimilated by new plants and trees. consumption for the production of ferromanganese is 2700 kWh/tonne FeMn (see previous chapter), which is equivalent to 4. Recovery of by-products. Silica dust can replace some of the 3460 kWh/tonne Mn. If the energy in the off-gases is recovered and cement in concrete. Since much C0 2 also is emitted in cement used for the production of electric energy, about 15 % of the input production, such a replacement might give a total reduction in COi electricity can be recovered (see chapter Energy Recovery). This emissions, and should consequently be recognised in an EPI reduces the net electric energy consumption to 2295 kWh/tonne indicator. FeMn, being equivalent to 2940 kWh/tonne Mn.

5. Energy recovery. We will discuss how energy recovered as heat Table 6 shows the changes in electricity consumption and C0 2 - or electrical energy should be assessed in an environmental emissions for a transition from ferromanganese to electrolytic performance indicator (EPI) for the plant. manganese.

The conclusion is that unless one has a lot of available hydroelectricity. it

Electrolysis is not even from an environmental point of view a good idea to ~hange from ferromanganese to electrolytic manganese. Manganese

Manganese metal is produced in an aqueous electrowinning process. Its standard reduction potential is 1.18 volts more negative than hydrogen. Manganese electrolysis is made possible by the high hydrogen overvoltage on manganese. The current efficiency for

Table 6. C0 2 -emissions for the production of ferromanganese and electrolytic manganese. Ail values given for a production of 1000 kg ( 1 tonne) Mn

FeMn: Electricity generated by: Hydro- Natural gas Coal UCPTE-mix Electric energy, kWh: 2940 2940 2940 2940

C0 2 emissions from el.gen., kg: 0 l 176 2881 1176

C0 2 emissions from C-red., kg: 2000 2000 2000 2000

C0 2 emissions sum. kg: 2000 3176 4881 3176

Electrolytic Mn: Electricity generated by Hydro- Natural gas Coal UCPTE-mix Electric energy, kWh: 8500 8500 8500 8500 C0 2 emissions·from el.gen., kg: 0 3400 8330 3400 C0 2 emissions sum, kg: 0 3400 8330 3400

Change in C0 2 emissions, kg: ~2000 224 3449 224

-89-

The The

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Proceedings Proceedings

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caused caused

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In In

amount amount by by

been been the the

carbon carbon

the the ferrosilicon ferrosilicon

The The

bio-carbon bio-carbon

process. process.

dioxide dioxide

among among

covers covers

biological biological

pyrolysis, pyrolysis,

new new

and and

interested interested programme programme

wi wi

reducing reducing carbon. carbon.

There There $/tonne $/tonne

regions, regions,

Today Today bringing bringing

production production to to

The The

make make

Norwegian Norwegian

especially especially wood) wood)

a a

coal coal

been been

million million

material material

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examples examples

production production

Looking Looking

II II

report report

most most

be be

addition addition

good good

2 2

baghouses, baghouses,

other other

processed processed

early early

threat threat

kg kg

not not

of of

use use

or or

found found

plants plants

done done

the the

a a

in in

are are

others others

by by

available available

dioxide dioxide

about about

homogeneous homogeneous

coke. coke.

all all

Si0

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formed formed

of of tonnes tonnes

Fix Fix

substantial substantial

regions regions

to to

used used

contribute contribute

practise practise

agents agents

But But

and and

of of

about about

the the

development development

parties parties

regions regions

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a a

back back

of of

use use

sufficient sufficient

for for

plants plants

raw raw

of of

seventies, seventies,

as as

only only

of of

the the

2 2 and and

aspects aspects

for for

plants plants of of

Ferroalloy Ferroalloy

major major

and and

price price

Carbon). Carbon).

to to

bio-carbon,which bio-carbon,which in in

overexploitation overexploitation

increased increased

per per

possible possible

with with

Brazil Brazil

same same

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copper copper

the the

costs costs

this this

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is is

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of of

in in

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silicon-metal silicon-metal

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environment environment

material, material,

this this

from from

source source

85 85

adding adding

to to

The The

from from

bio-carbons bio-carbons

because because

charcoal charcoal

in in

charcoal charcoal

kg kg

in in

to to

trees

and and

Norway Norway ferroalloys ferroalloys

today

for for

% %

production production

volatiles volatiles

district district

were were

ferroalloys ferroalloys some some

disposal disposal

% %

the the

project project

bio-carbons. bio-carbons.

the the

price price

Si. Si.

waste waste

to to

increase increase

Recovery Recovery

the the

of of

is is

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down down

these these

and and

of of

Norwegian Norwegian

for for

charcoal charcoal

trees trees

raw raw

forests forests

. .

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restrictions restrictions

the the

for for

an an

demand demand

Producers Producers

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atmosphere. atmosphere.

of of

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neighbourhood neighbourhood

Peat Peat

to to

using using

considerably considerably

Typical Typical

the the

it it

silicon-metal silicon-metal metallurgical metallurgical

but but

chips chips

iron. iron.

is is

exception, exception,

materials materials

bag bag

alone alone

heating

range range

made made

biological biological

greenhouse greenhouse

product, product,

sources sources

are are

has has

specific specific

has has

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huge huge

a a

and and

is is

problem. problem.

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like like

and and

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supplies supplies

considered considered

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industry industry

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is is

for for

started started

been been

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of more more

from from

The The

charcoal charcoal

forests forests

finally finally as as

silicon silicon

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increased increased

silicon silicon

by-products by-products

the the

. .

amount amount

Carbon Carbon

Research Research

on on

Research Research

ferrosilicon ferrosilicon

a a

probably probably

(deciduous (deciduous · ·

charcoal charcoal

is is

addition addition

wood wood

expensive expensive

as as

imported imported

these these

A A

general general

emissions emissions

to to

materials materials

more more

advantageous advantageous

COz-emissions COz-emissions

reckoned reckoned

industry industry

higher higher

ferroalloys ferroalloys

But But

or or

than than

or or

eucalyptus eucalyptus

the the

giving giving

a a

roasted roasted

precondition precondition

collect collect

effect, effect, of of

history, history,

to to

metal. metal.

will will

using using

planted, planted,

yields yields

research research

triple) triple)

like like

of of

2 2

Brazilian Brazilian

sources sources

used used

many many

the the

and and

by by

produced produced

produce produce

than than

watersheds watersheds

100 100

is is

felling, felling,

will will

Association Association

effect effect

silica silica

Council. Council.

to to

than than

not not

term term

be be

respectively respectively

that that

coal coal

will will

charcoal charcoal

carbon carbon

ferroalloys ferroalloys

as as

the the

silica silica

is is

woods woods

to to

because because

it it

OOO OOO

Up Up

wood wood

cement cement

charcoal charcoal

95 95

now now

from from

in in

cause cause

applications applications

we we

only only

be be

haulm haulm [6]. [6].

be be

from from

as as

industry industry

in in

what what

can can

at at

project project

dust dust

have have

for for

% %

to to

the the for for

to to

a a

"KLIMATEK"

charcoal charcoal

prodiiction prodiiction

the the

tonne tonne

we we

transportation, transportation,

assimilated assimilated

has has

dust dust least least

the the

for for

counted counted

are are

in in

nave nave

deforestation deforestation

of of

and and

Abo

m'lterial m'lterial

now now

and and

supply supply

be be

The The

and and

other other

silicon silicon

all all

collected collected

the the

one one

use use

bio-carbon

is is

(about (about

to to

the the

Norwegian Norwegian

have have

and and

resulted resulted

the the

(FFF) (FFF)

excluding excluding

ferroalloy ferroalloy temperate temperate

90 90

· ·

estimated estimated

started started

are are

the the

per per

l,!t.15000 l,!t.15000

aimed aimed plants plants

0.24 0.24

obtained obtained

concrete concrete

compete compete

charcoal charcoal

possibil" possibil"

thinning thinning

erosion. erosion.

for for

process. process.

this this

of of

project project

of of

several several

carbon carbon

severe severe

for for

% %

wood

used. used.

same same

extra extra

year, year,

used, used,

have have

as as

than than

bio

The The

of of

and and

400 400

and and

[7]

the the

has has

for for

the the

b) b)

in in

to to

in in

at at

a a

I I

, ,

. .

r , ,

furnace furnace

emissions: emissions: expect expect

or or

the the

Using Using

approx. approx.

instead instead

channels channels

reduced reduced

the the acceptable acceptable heat heat

minimisation minimisation

baghouse baghouse

furnace furnace

The The

a a

Ferrosilicon Ferrosilicon

temperatures temperatures

FeMn-production, FeMn-production,

SiMn-production, SiMn-production,

Using Using

FeMn-production, FeMn-production, following following

emission emission

instead instead

SiMn-production, SiMn-production,

Typically Typically

Using Using

the the

The The

uses uses

scrubbing scrubbing used used

in in Ferromanganese Ferromanganese

for for

*)For *)For

tonne tonne the the

production production 2 being being

kg kg

In In

strength. strength. tensile) tensile)

cement cement

gas gas

coal. coal.

5 5

energy energy

the the

cement cement

For For

input input

cement. cement.

silicon-metal silicon-metal

development development

bag bag

. .

cement cement

kg kg

for for

as as use use

flow flow

the the

The The

to to

the the

in in

sixties sixties

of of

0 FeSi:

the the

Si: Si:

approx. approx. of of

by by

36 36

If If

of of

to to

can can

a a

filters, filters,

this this

recover recover of of

electric electric

per per

off-gas off-gas

the the

natural natural

is is

1 1

C02 C02

we we

of of

natural natural

synthesis synthesis

major major

the the is is

is is

temperature temperature

mixing mixing

(Venturi (Venturi

of of

4 4 off-gas off-gas

GJ GJ

production production

C02 C02

gas gas

kg kg

gas gas

the the

Thus Thus

be be

as as

for for

( (

energy energy

and and

specific specific

tonne tonne

weight) weight)

( (

of of

can can

above above

roughly roughly

sealed sealed

16 16

(8). (8).

energy energy

0.38*2.5) 0.38*2.5) silica silica

per per

6 6

replaced replaced

credit credit

which which

54 54

high high

for for

emission emission

24*2.5/0.75) 24*2.5/0.75)

heat heat

the the

instead instead

application. application.

about about

for for

gas gas

energy

oncrete. oncrete.

silicon-metal silicon-metal

expect expect

gas gas

70 70

the the

70 70

emissions. emissions.

of of

The The 50 50

it it and and

50 50

tonne tonne

from from

ferroalloy: ferroalloy:

GJ GJ

. .

scrubbers) scrubbers)

heat heat gas gas

the the

heat heat

gas gas with with

dust dust

250 250

is is

% %

generation, generation,

% %

furnaces furnaces

/kWh /kWh

C02 C02

% %

/kWh /kWh

% %

is is

replacement replacement

is is

as as

will will

semiclosed semiclosed

for for

collect collect

proportional proportional

the the

20 20

per per

silicomanganese silicomanganese

equivalent equivalent

clean clean

for for

CO CO

. .

CO CO

equivalent equivalent

CO CO

solution solution

CO CO

used used

by by

or or

volume volume

a a

to to

* *

Energy Energy

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generation generation

FeSi FeSi

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800 800

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°C. °C.

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% %

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C02 C02

ferrosilicon ferrosilicon

increase increase

1000 1000

the the

tonne tonne

silica silica

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recover recover

in in

emission emission

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in in

[8]. [8].

in in

coal coal

of of

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tonne tonne

gas gas

replace replace

* *

Giving Giving

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Cooling Cooling

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means means

°C. °C.

off-gas: off-gas:

off-gas

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off-gas: off-gas:

bag bag

amounts amounts

1000 1000

heat heat

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the the

kg= kg=

the the As As

emissions emissions

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will will

as as

dust dust

even even

containing containing

recovery recovery

Si. Si.

addition addition

generation generation

silica silica

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with with

to to

Cooling Cooling

input input

filters filters

ferroalloy: ferroalloy:

highly highly

up up

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or or

generation. generation.

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kg.= kg.=

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removal removal

removing removing

3 3

The The

that that

950 950

or or

for for

removing removing

be be

equivalent equivalent

: :

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ferrosilicon ferrosilicon

and and

650 650

to to

450 450

electric electric

kg kg

350 350

been been

250 250

furnace furnace

the the

established established

dust, dust,

capital capital

I I

the the

of of

strength strength

electric electric

electrical electrical

to to

FeSi FeSi

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800 800

15 15

kg kg

we we

releases releases

cement. cement.

most most

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wanted. wanted.

air air

kg kg

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kg kg

are are

off-gas off-gas

kg kg

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where where

% %

volumetric volumetric

50 50 found found

of of

silica silica

can can

cannot cannot

kg kg

from from

is is

of of

and and C0

the the

power power

0.8 0.8

as as

requirement requirement

has has

the the

economical economical

electricity, electricity,

for for

If If

to to

possible, possible,

power power

gas gas

to to

deduct deduct

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(compressive (compressive

2 2

electric electric

concrete concrete

and and

following following

energy. energy.

there there

vast vast

950 950

/tonne /tonne

dust dust 70% 70%

/tonne /tonne

dust dust

/tonne /tonne

This This

following following

practice practice

a a

natural natural

from from

that that

an an

the the

electric electric

be be

l l

removing removing

in in

generation generation

silicon-metal silicon-metal

.O .O

down down

dust dust

silicon-metal silicon-metal

kg kg

enthalpy enthalpy

amounts amounts

will will

(10-30 (10-30

the the

exposed exposed

CO CO

is is

kg kg

part part

off-gas off-gas

has has

generation generation

gas gas

800 800

SiMn SiMn

but but

the the

energy energy

FeMn FeMn

per per

no no

will will

gas, gas,

we we

off-gas off-gas

by by

for for

energy. energy.

use use

already already

remove remove

can can

led led

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kg kg

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C0 flow, flow,

gives gives

open open

other other

tonne tonne

can can

2 2

% %

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the the

oil oil

wet wet

the the

and and

an an

of of

per per of of

of of

per per

the the

to to

2 2 be be

is is

of of

power power

FeMn FeMn

to to

FeMn FeMn

In In Net Net

FeSi FeSi

Si Si

FeSi75 FeSi75 Si-metal Si-metal SiMn SiMn

Si-metal Si-metal

FeMn FeMn

Energy Energy

Si Si

Si-metal Si-metal

FeSi75 FeSi75

SiMn SiMn

Recovery Recovery

FeSi75 FeSi75

SiMn SiMn Fe Fe Si-metal Si-metal

Fe Fe Si-metal Si-metal

FeSi FeSi

Ferroalloy Ferroalloy

Using Using

can can

Silicon-metal Silicon-metal

We We Silicon-metal Silicon-metal

Ferrosilicon Ferrosilicon following following

Ferrosilicon Ferrosilicon

Situation Situation

;; ;;

0 0

.! .! ......

u u

N N

!}. !}.

s s

" "

"' "'

g g

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~ ~

c c

Mn Mn

reduce reduce

Fig. Fig.

Mn Mn

C02 C02

4000 4000

make make

6000 6000

will will

8000 8000

2000 2000

Fig

75 75

including including

sources sources

20 20

3 3

the the

recovery recovery

. .

the the

sum sum

3 3

COi-emissions. COi-emissions.

of of % %

where where

Table Table

to to

emissions: emissions:

off-gas off-gas

silica silica

net net

biu-carbun biu-carbun

production: production:

reduce reduce

production production

up up

2 2

production: production:

taking taking

/Nuclear /Nuclear

-3000 -3000

-2000 -2000

Hydro-

1190 1190

1350 1350

present present

2 -310 -310

-250 -250

-450 -450

-950 -950

COi-emissions COi-emissions

-800 -800

-910 -910

-876 -876

704 704

Adding Adding

-emissions -emissions

present present

2000 2000

2050 2050

8. 8.

4550 4550

4380 4380

emission emission

the the

0 0

O O

instead instead

dust: dust:

Possible Possible

different different

credit credit

The The

2 2

and and

in in

and and

up up

: :

of of

per per

2800 2800

emissions emissions

pruducliun pruducliun

Ferroalloy Ferroalloy

2000 2000

3000 3000

for for

different different with

4200 4200

reductions reductions

possible possible

coal coal

possible possible

Proceedings Proceedings

contributions contributions

Natural Natural

tonne tonne

-3000 -3000

-2000 -2000

4690 4690

4224 4224

2480 2480

2990 2990

present present

-250 -250

-450 -450

7900 7900

3130 3130

3850 3850

9550 9550

-950 -950

-800 -800

-876 -876

-910 -910

are are

gas gas

kg kg

0 0

O O

is is

kg kg

plotted plotted

equivalent equivalent

ferroalloy: ferroalloy:

and and

contributions contributions

of of

and and

in in

2 2

/tonne /tonne

2 /tonne /tonne

FeSi FeSi

greenhouse greenhouse

/tonne /tonne

-contributions -contributions

power power

for for

possibl'e possibl'e

10740 10740

-4200 -4200

-2800 -2800

the the

16800 16800

3896 3896

5400 5400

8528 8528

13004 13004

4646 4646 -350 -350

-650 -650

6460 6460

-950 -950

-800 -800

-910 -910

-876 -876

Coal Coal

2 2

0 0

O O

and and

different different

to to

FeSi FeSi

ferroalloys ferroalloys

FeSi FeSi

Si Si

emissions emissions

Si Si

of of

sources sources

removing removing

Si-metal Si-metal

contributions contributions

are are

INFACON 8 INFACON

effects

• •

c c

UCPTE-mix UCPTE-mix

Hydro-/Nuc:] Hydro-/Nuc:]

electric electric

not not

UCPTE·mix UCPTE·mix

-3000 -3000

-2000 -2000

Natural Natural

4690 4690

4224 4224

2480 2480

2990 2990

-250 -250

-450 -450

7900 7900

3130 3130 -950 -950

3850 3850

-800 -800

9550 9550

-876 -876

-910 -910

industry industry

the the

0 0

. . 0 0

O O

included: included:

-91-

Coal Coal gas gas Comparing energy carbon

The

This

Ferroalloy

acknowledged. Research

2. Hill

Energiesy Bio-carbon 5

Situation 76-79.

6. Europe", Norwegian)

4. TSS-AIME, 9.

Proceedings

8. Okobilanzen Vergleich "Energy Electrowinning

Nov

115-7.

1996

1997.

. .

J the

A l

L.Kolbeinsen,

Metal

R.A.Person: .

Fageras

Thonstl)d

R.Stubergh

Book

Hallgren:

Rosenqvist:

1993.

work

Proceedings

total

vol.

Frischknecht

from

Melgaco:

Recovery

Bulletin

ISS-AIME

and

Co.,

von

Council

27B,

temen

COi-emissions

the

Figs.

Electric

Saur,

Producers

a been has

INFACON

the

Stiftelsen

fiir

Silicon-metal

private

"Disposal

Outlooks"

Energiesy

"Current

furnace

and

895-900.

off-gas

die

"Principles

"The

und

No.

Ed.,

Lindstad,

and

et.al.

Bytownite-Cryolite Z

Furnace

Schweiz.

Electric

Lerche

the

8193,

den

communic

Liu New

0stfoldforskning,

Brazilian

financially

;

Acknowledgement

.),

Norway

8, of

and

Research

St~

Norwegian

temen

Proc.

Einbezug

Grundl

caused

Trondheim

"Preparatio

Fume

York,

tus

References

and

INFACON

Proceeding

Furnace

possible

recover

July

Bunde

see

Extractive

adal

Tveit

INFACON

und

Ferr

Ferro

age

tion

from

Ferroalloy

(NFR).

1983,

that

1997.

Association

and

von

Ferro

den upported

sa os

ferroalloy

Proceedings

:: with

by-product

fiir

mtes

ilic

Submerged

1995

lloy

s, Melt",

445.

Energiesystemen

Einbezug

get

Bruno

Fredrikstad,

den

metallurgy",

Erstad:

1975,

using

Alloy

Pure

author,

fiir

Industry

Production"(In

165-177

Emission

Trondhe

usata reduction substantial

Metal!.

production

Energiewirthsch

and

Silicon

Vol

partly

Industry

are

(FFF)

"Increa

Vol.

(silica-dust)

gisc NTNU,

von

The

Arc

L.N

im,

both

Tran

McGraw

996.

Current

(20

33,

Furnaces

Control"

y en

Norwegian

gaard:

and

1995

July

1975

39-46.

greatly

Use

)

bio

The

and