tk Polysius

Metallurgical Injection Technology

Our new name is

ThyssenKrupp Industrial Solutions

www.thyssenkrupp-industrial-solutions.com

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For the production of high-grade steels, hot metal desulphurisation is absolutely essential. Desulphurisa-tion plants from ThyssenKrupp Polysius reliably and precisely reduce the sulphur content of the hot metal. The treatment process can take place in transfer ladles or torpedo ladles.

On the secondary metallurgy sector, ThyssenKrupp Polysius supplies injection systems for steel treatment in transfer ladles.

Depending on the objective of the steel treatment, different agents or combinations of agents can be injected into the molten steel.

For the utilisation of residues in steel works, ThyssenKrupp Polysius offers injection plants for conditioning converter slags and for recycling filter dust from the electric arc furnace.

Having built more than 150 such plants all around the world, ThyssenKrupp Polysius possesses com-prehensive and well-founded system- and process-technological know-how.

As one of the world’s leading companies in the plant engineering field, ThyssenKrupp Polysius has the comprehensive know-how that is needed in order to supply the minerals industry with innovative but tried and tested processes, plants and system configurations.

Our continuous development and optimisation of plant concepts, processes and equipment in combination with decades of practical experience guarantee custom-ers state-of-the-art, reliable technology with maximum performance and minimum operating expenses. Our products fulfil the most stringent quality requirements and provide long service lives and low maintenance requirement.

Reliable plant technology Backed by more than 50 years’ experience made by ThyssenKrupp Polysius

The iron and steel industry’s partner for …

Hot metal desulphurisation✓

Steel treatment✓

Conditioning of converter slag✓

Filter dust recycling✓

Pneumatic conveying systems✓

Optimisation and modernisation✓

CaO CaC2

Mg

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In modern integrated metallurgical plants producing high grade steels, the hot metal desulphurisation takes place outside the blast furnace. The desulphurisation process precedes the steel treatment in the converter.

For this external hot metal desulphurisation, the dip-lance method has established itself as the most reliable and cost effective process.

For this reason, most steel works selectively reduce the hot metal’s sulphur content in charging and trans-fer ladles using the dip-lance method.

ThyssenKrupp Polysius has developed injection tech-nology for this process for more than 35 years now.

Starting with the desulphurisation of hot metal in torpedo ladles, this proceeded through the injection of calcium carbide to the latest method of Multi-Injection, using lime, calcium carbide and magnesium and applying state-of-the-art instrumentation and control.

What makes the dip-lance method so effective for hot metal desulphurisation is the precisely dosed pneumatic injection of powdery desulphurisation reagents into the molten metal via refractory lances.

This achieves intimate mixing of the hot metal with the desulphurisation reagents. The dip-lance method can reliably reduce the sulphur content of the hot metal to figures as low as 0.001 percent (10 ppm).

ThyssenKrupp Polysius developed a mathematical model for hot metal desulphurisation, which – com-bined with state-of-the-art plant technology – assures high plant availability and highest possible through-put rates.

The use of effective desulphurisation reagents such as lime, calcium carbide and magnesium, minimises the amount of slag while simultaneously cutting the process time and greatly reducing the hot metal losses during deslagging.

Principle of the

multi-injection process.

Hot metal desulphurisation plants ... Precision work for every requirement

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CaC2

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To assure operating cost minimisation, the combina-tion of dip-lance method with mathematical process model and flexible plant control offers a range of pos-sible process technological variations.

One of these possibilities is to vary the injection rate [kg/min] to suit the production conditions. This must take account of the fact that the effectiveness of hot metal desulphurisation is inversely proportional to the desulphurisation reagent injection rate. In accordance with the length of time available for the treatment pro-cess and under consideration of all further parameters, the system then selects the most cost effective pro-cess.

Another possibility is to inject different desulphurisation reagents during one hot metal treatment session. The desulphurisation reagents can be injected singly, simul-taneously or with a time lag. These process options are called Mono-Injection, Co-Injection and Multi-Injection.

Which of the above processes achieves the lowest op-erating costs is determined by the operating and pro-duction conditions, which can vary from batch to batch. Among the important factors taken into account by the mathematical model devised by ThyssenKrupp Polysius are the weight, temperature and analysis of the hot metal, the target sulphur content, the properties of the blast furnace slag and the available injection time.

To be able to select the optimum process at any time and thus flexibly adapt the hot metal desulphurisation plant to the respective operating and production condi-tions, a comprehensive knowledge of the metallurgy of the hot metal desulphurisation process is required.

Selection of the optimum process is performed by a metallurgical process computer. The effectiveness of the process is therefore decisively determined by the “programmed process knowhow”.

Due to the large number of plants already supplied, ThyssenKrupp Polysius possesses comprehensive knowledge. This is implemented in the metallurgical process computer that our company developed, and thus benefits our numerous clients all around the world. The metallurgical sequence program contains mathematical equations which reflect the regularities of hot metal desulphurisation, so that every individual hot metal batch is desulphurised with the optimum pro-cess.

Dip lance

process variants.

Control level

mask.

Preassembly in

the workshop:

arrangement of

dispensers for

the multi-injection

process.

Control room with

host computers.

Masks with treatment

parameters

(right-hand photo).

Hot metal desulphurisation processFlexible. Effective. Economical.

Mono-Injection

Co-Injection

Multi-Injection

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ThyssenKrupp Polysius provides metallurgical plant technology that is tailored to the individual range of products and the general operating conditions of the steel works.

All plant components come from a single source, starting with the un-loading station for bulk transporter vehicles or tank wagons, through storage silos for the desulphurisation reagents, the pneumatic dispensers, the injection lance insertion unit, au-tomatic lance changing equipment, temperature measurement and sam-pling devices, slag skimming ma-chines and onward to the electrical control systems, control panels and electrical equipment and the metallur-gical process computer.

Custom-tailored treatment stations with ladle transfer car or hood car-riage round off the range of products.

ThyssenKrupp Polysius also per-forms the extension, modernisation and optimisation of existing plants.

Our comprehensive scope of services also includes field assembly, com-missioning and plant and process inspections at existing plants.

The core system in the ThyssenKruppPolysius desulphurisation technology is the injection system known by the proprietary name MEPOL.

The most important components of the MEPOL system are pneumatic dispensers with five harmonised measurement and control units for recording, monitoring and controlling all operating parameters that have an influence on the process and the dosing precision.

Combined with the metallurgical process computer, the MEPOL system ensures reliable and stable plant operation as well as the cost-optimised desulphurisation of every single hot metal batch.

Plants designed by ThyssenKrupp Polysius make use of high-quality components. Great importance is placed on effective wear protection. Valves and hoses exposed to the flow of material are therefore fitted with wear-resistant components made of ceramic or are provided with wear-reducing coatings.

MEPOL principle.

Ladle transfer car with tilting

device for a hot metal ladle.

Wear-

resistant

components

of the

discharge

control

valve.

MEPOL control system

with operator panel.

Pneumatic dispenser for

the injection of reagents.Wear-resistant MEFLEX

conveying hose.

Slag skimming machine

– also remotely controllable

from the control room.

Injection technologyDispenser with MEPOL system

Innovative and reliableRight down to the details

1 Control of top pressure2 Control of fluidisation gas3 Discharge control valve4 Discharge weighing

(measurement of injection rate)5 Control of conveying gas

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Layout and functional diagram

of a hot metal desulphurisation plant

with two treatment stations.From the detail to the complete solutionEverything from a single source