chapter 9 4 nfm draft bat conclusions

8/11/2019 Chapter 9 4 NFM Draft BAT Conclusions

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EUROPEAN COMMISSIONJOINT RESEARCH CENTREInstitute for Prospective Technological StudiesSustainable Production and Consumption UnitEuropean IPPC Bureau

Seville, 26 May 2011

Proposals for new NFM BAT conclusions for Ferro-Alloysproduction

9.4 Best available techniques for Ferro-Alloys

Key environmental issues for the production of ferro-alloys are: dust and fume,

CO and CO2gas, SO2, energy recovery, waste water, residues such as filter dust,sludge and slag.

Air

BAT Process control: see Sections 2.5.1, 2.5.2, 2.6.1.

Raw materials storage and handling

Transport of raw materials such as char coal, coke and coal

< 3 mg dust/Nm3measured, always < 20 mg dust/Nm

3.

(Where are these data from?)

Displaced air cleaning

Handling, storage and transport of very fine powders can create problems

The BAT-AEL for dust is < 1 to 20 mg/Nm3.

Burden preparation (crushing,weighing, mixing, blending) and conveying

BAT is to minimise dust emissions by appropriate measures and, where relevant,

to extract emissions with subsequent purification by means of dry dedusting.

I. Wet grinding, filtering, pelletising

(measured at the homogenization of charge mix for themetallothermic reductionprocess showed emissions concentration values of 0.2 mg dust/Nm3. [255])

The BAT-AEL for dust is < 1 to 20 mg/Nm3.

Pretreatment stages such as coke and raw material drying, prereduction and

preheating, drying and degreasing of secondary raw materials

Raw material drying in rotary drums or kiln furnaces

Shaft furnace for coke drying

BAT-AEL for FF 5 mg/Nm3

Rotary kiln

???DC Plasma process


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BAT for the drying and degreasing of raw materials is to apply a rotary kiln,

afterburner for VOC

BAT-AEL for dust 5 mg/Nm3and VOC 20 mg/Nm

3?

Sintering plant

BAT for sinter plants is to reduce dust emissions by applying the followingtechniques individually:

I. wet scrubber

II. FF

The BAT-AELfor dust is


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Do we have example plants? What are the residual SO2concentrations?We have SADACI, Ghent, Belgium with conversion rate between 99 and 99.4 %

BAT for Dioxins , HCN, vaporised metals such as Hg, Cd, Pb?? PAH?

If dusts from steel mills are recovered it is quite likely that HM can be emitted. Two stage bag

filter with injection of activated carbon or a 3 stage venture scrubber or wet ESP with

subsequent mercury removal with selenium filter can be applied. Try to get further

information.

SO2: Depends on the sulphur content of the input materials. Are any requirements necessary?

Dioxins: very low concentration values are reported. Nevertheless industry proposes very

high values (see Excel spread sheet). Is there any BAT for dioxins or only prevention?

Decide if something is needed in the material selection and pretreatment stage for dioxins

and Hg in particular.

Post furnace operations

BAT for tapping (oxygen lancing, drilling, vaporised slugs if tapping guns are

used), melt refining and casting from all exposed metal and slag furnaces is to

prevent or reduce diffuse emissions by applying the following techniquesI. complete fume collection enclosures

II. casting spout capture hoods

III. cast house canopy hoods

IV. vortex capture hood if applicable

Optimising the capture efficiency for diffuse dust emisissions and fumes with

subsequent cleaning.

The BAT-AELfor dust is < 1 10 mg/Nm3, determined as a daily mean value.

BAT is to minimise dust emissions from size reduction, screening and packaging

of alloys to extract emissions by applying one of the following techniques with

subsequent purification by means of dry dedusting.

I. totally enclosed systems

II. crushers with capture hoods

The BAT-AELfor dust is < 1 10 mg/Nm3, determined as a daily mean value.

(values < 3 mg/Nm3have been measured. [255] enclosed systems!)

Handling, storage and transport of very fine powders can create problems:

Densification of silica powder

Water

Water consumption and discharge

BAT is to minimise the water consumption from the smelting process by the use

of closed loop water cooling systems for the cooling of furnace devices and by the

use of treated waste water for metal and slag granulation and cooling.

(Quenching of off-gas?)

BAT is to minimise the waste water discharge from wet scrubbers, cooling

systems and granulation processes by applying the following techniques in

combination:


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I the removal of cyanide and fluoride

II. the reduction of Cr6+ to Cr3+, precipitation of metal hydroxides together

with oxidation of cyanides

III. removal of solids by sedimentation, flocculation and/or filtration

IV. in the case of molybdenite roasting ion exchangers

The BAT AELsfor waste water after treatment is:

Suspended solids < 20 40 mg/l

In Section 9.2.4 are no data for waste water after treatment. Only emission factors for the

treated scrubbing water from plasma dust process and the roasting of molybdenite. Where

are the data from Section 9.4.2 from?

Production residues such as wastes and by-products

Minimising slag treatment emissions

Slag granulation and water spraying to reduce dust emissions

See tables 9.31 and 9.32 in Section 9.4.3 of the draft of the NFM BREF.

BAT is to prevent waste generation by applying the following techniques

individually or in combination (see Sections..):

I. appropriate collection and storage to facilitate a specific treatment

II. on-site recycling of dust and sludge from gas treatment and pretreatment

processes, dust from crushing, raw material and product transport and

handling, secondary dedusting and mill scale from continuous casting

back to the ferro-alloy making processes with due regard for the effect of

emissions from the plant where they are recycled

III. on-site recycling of ferro-alloy slag and ferro alloy fines in various

applicationsIV. use of MnO rich slag as raw material for the production of silico-

maganese or other metallurgical applications , use of FeV and FeCr-slags

i.e. in the steel industry

V. slag treatment where market conditions allow for the external use of slag

(e.g. as an aggregate in materials or for construction, sandblasting,

production of refractory castables or refractories)

VI. use of filter dusts and sludge for external recovery of alloys in the non-

ferrous metals industry, e.g. ISP or waelz kiln

VII. use of a settling tank for sludge with the subsequent recycling of coarse

fraction in the sinter/blast furnace or cement industry when grain size

distribution allows for a reasonable separation.

Ferro-alloy production residues which can neither be avoided nor recycled

should be managed in a controlled manner.

Energy

BAT for the production of HC FeCr, HC FeMn and SiMn is to apply closed

furnaces and to collect, clean and buffer CO rich off gas for subsequent use as a

fuel or raw material where prerequisites are given individually or in

combination for

I. coke drying

II. sintering

III. preheating of burden


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IV. heating of ladles

V. production of electrical energy

VI. heat and steam production

VII. use as a raw material in the chemical industry

BAT for the production of FeSi, Si-metal, and FeNi is to apply semi-closedelectric arc furnaces where prerequisites are given and reduce/minimise thermal

energy consumption by applying the following techniques individually or in

combination:

I. process integrated re-use of sensible heat as far as possible from the off-gas

II. using sensible heat for internal and external heating networks if there is a

demand from a third party (the cooperation and agreement of a third party

may not be within the control of the operator, and therefore not be within the

scope of an IPPC permit).

(What about oxygen blowing converters, crucibles, plasma dust process or other

furnaces? Is there any energy recovery, or CO recovery??)

BAT is to reduce energy consumption by covering ladles with a lid during

transport where prerequisites are given.

Noise

??

EAF can be quite loud, see iron and steel BREF requirements

chapter 9 4 nfm draft bat conclusions

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