Optimization of the AO stainless steel processing cost by ...706106/FULLTEXT01.pdf · 5 Figure 1 Trend of stainless steel price from 2012 – 2013[3] 1.2 AOD/CLU The stainless steel

KTH

Optimization of the AOD stainless steel processing cost by the UTCAS System

Chay Ta-uar

800521-T290

The Argon Oxygen Decarburization (AOD) process is one of the major stainless steel refining routes. Several

parameters come into play deciding the outcome of the process. The task focuses on studying an optimized

processing in an AOD converter using the UHT’s Converter Automation System (UTCAS)-process control

program. The process parameters that mostly influence the process are studied and their effect on the process are

analyzed. The 304, 409, 316, 430, 201, 2205 stainless steel grades are chosen for this study. The input temperature,

input element content (carbon, chromium, nickel, silica, molybdenum and manganese), input steel mass are varied

individually keeping all the other parameters constant and their effect on the process is analyzed. The parameters

like process time, amount of gases (O2, N2 and Ar) consumed, amount of reducing agent (FeSi) and amount of alloy

addition are taken into consideration to decide the optimal outcome of the process. The number of gas blowing steps

is also varied to study its influence on the AOD process. This is done at different process initial input to also study

the effect varying parameters on the stainless steel process. After analyzing the effect of all the parameters

suggestible range of values for the parameters are proposed for on optimal blowing in an AOD converter.

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Acknowledgement First and foremost, I would like to thank to my supervisor of this project, Mr. Carl Johan Rick and Mr.

Mikael Engholm for the valuable guidance and advice. He inspired me greatly to work in this project.

They willingness to motivate me contributed tremendously to my project. I also would like to thank them

for showing me some examples that related to the topic of my project. Besides, I would like to thank the

authority of Uvan Hagfors Teknologi AB at Kista and Uddelholm for providing me with a good

environment and facilities to complete this project. Also, I would like to take this opportunity to thank

Prof. Pär Jönsson for recommendation my subject and his support rendered at times in the starting the

project. Without helps of the particular that mentioned above, I would face many difficulties while doing

this.

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Contents Acknowledgement ........................................................................................................................................ 1

1. Introduction ............................................................................................................................................... 4

1.1 General ................................................................................................................................................ 4

1.2 AOD/CLU ........................................................................................................................................... 5

1.3 Process model used for simulations .................................................................................................... 7

1.4 Aim of study ....................................................................................................................................... 9

2 Experimental set up .................................................................................................................................... 9

2.1 Stainless steel and raw materials composition .................................................................................... 9

2.2 Final weight controls ......................................................................................................................... 12

2.3 Temperature controls ........................................................................................................................ 13

2.4 Parameters control ............................................................................................................................ 13

2.4.1 Trial conditions for stainless steel grade 304 ............................................................................. 13

2.4.2 Trial conditions of stainless steel grade 409 .............................................................................. 14

2.4.3 Trial condition of stainless steel grade 316 ................................................................................ 15



2.4.6 Trial condition of stainless steel grade 2205 .............................................................................. 16

2.5 UTCAS interface set up .................................................................................................................... 18

2.6 Cost model set up .............................................................................................................................. 21

3. Result ...................................................................................................................................................... 23

3.1 Stainless steel grade 304 result ......................................................................................................... 23





3.6 Stainless steel grade 2205 result ....................................................................................................... 28

4. Discussion ............................................................................................................................................... 29

4.1The oxygen injection through the oxygen lance ................................................................................ 29

4.2 The initial steel melt composition ..................................................................................................... 29

4.3 Superheat steam injection (AOD/CLU) ............................................................................................ 29

4.4 Compressed air injection ................................................................................................................... 29

4.5 Alloying materials selection.............................................................................................................. 30

4.6 Extra blowing .................................................................................................................................... 30

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4.7 The time adjustment .......................................................................................................................... 30

5. Conclusion .............................................................................................................................................. 30

6. Future work ............................................................................................................................................. 31

7. Reference ................................................................................................................................................ 31

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1. Introduction

1.1 General

Stainless steel is widely used in various applications this is due to that stainless steel has a CrO3

film coat on the surface for anti-corrosion when the steel is exposed to a corrosive environment.

Therefore, all stainless steels are corrosion resistance as well as provide ranges of strength, formability,

and high or low temperature service. In addition, other elements also have different advantages when they

are added to the steel. Thus the stainless steels are primary classified as austenitic, ferritic, martensitic,

duplex or precipitation hardening grades depending on the composition and treatment. Typical wrought

alloy AISI series designations include 200 (high manganese austenitic), 300 (austenitic), and 400 (ferritic

or martensitic). Martensitic and ferritic steels are magnetic. Martensitic steels are typically hardened by

heat treatment and are not easily formable. Austenitic steel grades can be harder by cold work. Duplex

grades (austenitic/ferritic) are more resistant to stress corrosion cracking than austenitic and are tougher

than ferritic grades. Precipitation hardened grades (martensitic or austenitic) are strengthened during heat

treatment by precipitation hardening [1] as shown in Table 1.

Table 1 stainless steels grades including properties and applications [2]

stainless steel grade properties application

304 Austenitic Cr-Ni stainless steel ,non-

magnetic, low carbon content, weld ability

Cooking equipment, pressure

vessel, kitchen sink, food

processing equipment etc.

316 Austenitic stainless steel, excellent corrosion

resistance, elongation and ductility

Mirror, marine, medical, food

industry etc.

409 Ferritic stainless steel, low Cr composition,

weld ability without post weld annealing

Exhaust pipe, fuel filter, blade or

vane in generator turbine,

electrical transformer etc.

430 Magnetic in all condition, good physical and

mechanical characteristics, cost less than

chromium-nickel stainless steel

Cabinet hardware, decorative

appliance and automotive

molding and trim, restaurant

equipment etc.

201 Austenitic chromium-nickel-manganese

stainless steel, non-hardenable by heat

treatment but cold work be done, non-

magnetic in the annealed condition

Cookware, hose clamps, piston

rings, air bag container etc.

2205 High strength, excellent corrosion resistance,

corrosion cracking resistance, pitting

resistance, low thermal expansion

Heat exchange, piping, paper

production equipment etc.

The goal is to produce a good quality stainless steel at a low cost with a low amount of by-products

which negatively affect the environment. In addition, there is a trend that the stainless steel price

decreases as seen in Figure 1.Therefore, stainless steel producer have to optimize time, alloying raw

materials, by- products in the stainless steel process to compensate for the lower prices.

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Figure 1 Trend of stainless steel price from 2012 – 2013[3]

1.2 AOD/CLU

The stainless steel refining process is one step in a stainless steel production. This study will

focus on the Argon Oxygen Decarburization/ Creusot Loire Uddeholm-process (AOD/CLU) process,

which are used in many stainless steel plants such as Outokumpus Avesta Works and Acerinox’s

Columbus Stainless Works. This technic was first introduced with an AOD installation in Joslyn,USA

1968[4] . However before the AOD installation in 1950, Union Carbide AB showed that a low carbon

concentration could be reached without an excessive chromium oxidation by adding argon together with

the oxygen during decarburization. The AOD process has basic features are decarburization, reduction,

sulphur refining (desulphurization).

Decarburization, the carbon removal is done by oxygen blowing. During oxygen is injected in to

a steel bath, chromium and iron will oxidize. Decarburization occurs when dissolved carbon

reduces the chromium and iron. If only chromium is considered, the overall reaction can be

expressed as seen in equation ). The

equilibrium equation for this reaction is given by

equation (

) ), where , and are the

activities of carbon, chromium and chromium oxide respectively, is the partial pressure of

carbon monoxide (CO) in the gas phase and K is the equilibrium constant.

(

) )

Based on equation 2 and the assumption that equals unity, the equilibrium carbon

concentration [ ] can be calculated from

equation[ ] [ ]

), where and are the activity

coefficients of carbon and chromium respectively and [ ] is the concentration of chromium.

From this equation, it is evident that the equilibrium carbon content is lowered if is

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decreased. Under conditions where all injected oxygen has reacted with carbon, (CRE=100) that

mean all oxygen react with C give Pco the partial pressure of CO can according to the gas law as

seen in equation

) where is the volumetric

amount of generated CO, is the volumetric amount of injected nitrogen or argon and

is the total pressure. Then the ratio of oxygen to inert gas can be optimized for any combination

of carbon with chromium concentration.

[ ] [ ]

The example of decarburization strategies are explained in Table 2 and Figure 2. Then the

decarburization process based on a stepwise decrease of the oxygen with inert gas ratio

strategies.[4]

Table 2 Ratio of oxygen with inert gas during decarburization

Oxygen/inert Condition

3/1 c ≥ 0.6

1/1 0.6 < c ≥ 0.25

1/3 0.25 < c ≥ 0.07

1/3 c < 0.07

Figure 2 shown Carbon Removal Efficiency (CRE) step during decarburization [5]

Not only carbon will be removed during the decarburization procedure, but also other elements

with high affinity to oxygen such as silicon, manganese, chromium and nickel. Stainless steel is

highly alloyed with chromium and nickel. Chromium and nickel, as well as iron, will oxidize

during the decarburization. A major loss of valuable chromium to the slag in the form of oxides is

not acceptable.[6]

A reduction process will be activated after the amount of carbon reach the goal by adding a

reducing agent such as FeSi to reduce valuable oxide materials such as Cr2O3 from slag back to

Cr into steel melt. During these processes, the steel melt can reach too high temperature. Then the

operator would add a coolant material, which does not affect the aim composition to avoid an

excessive temperature that affects the refractory wear consumption.

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Sulphur refining is done by using inert gas blowing such as argon or nitrogen in the steel and by

controlling the sulphide capacity of the slag.

Nevertheless, the AOD process still requires a good inert gas supply, but some plant encounter with gas

supply problem. Thus the CLU process was developed to substitute inert gas by using super heat steam

as

(5).

(5)

Δ H=+241.9 kJ/mol

The formed hydrogen acts as an inert gas to replace argon or nitrogen, while the oxygen oxidized the

carbon in the steel. The use of 1 kg of steam substitutes for 1.25 Nm3 Ar (or N2) and 0.625 Nm3 O2 in the

converter.[7] A boiler is used to produce steam. This steam must be dried using a super-heater before it

becomes suitable as a steelmaking process gas. To enable blowing of a dry gas in to the converter, it is

necessary to preheat all process gases. This is done in a heat exchanger. A logical process flow diagram

is displayed in Figure 3

Figure 3 Typical configuration of a steam generator in relation to a refining converter [8]

1.3 Process model used for simulations

The UHT Automation System (UTCAS) is an advance computer system designed for converter

process management. The system can be controlled in real time or used off line. A core models calculates

heat, mass balance and chemical composition continuously during the process. The models are also used

to generate a forecast, predict the final temperature, final weight, final compositions, time consuming, raw

materials used base on raw materials adding and gas blowing plan. The concept of UTCAS system is

described in Figure 4. This system will show result after design and provide the designed data to a level 1

operation system. In order to produce good stainless steel, the system will receive data from a post

processing system and optimize the process before the next process. Thus the operator can check

feedback result and make decision to adjust optimized process.

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Figure 4 The UTCAS concept for process control and management [9]

The UTCAS system provides data to enable a level 1 control and it also receives feedback from a process

shown on an operator screen, as seen in Figure 5.The main calculation steps to determine the required

material amounts and distribution are as follow [9]

An advance simplex kernel algorithm is used to calculate and compare the input data and

optimize by relate to metallurgical process. This program is used to determine the total amounts

of alloys, mass build up materials, reduction agents and slag formers in order to reach the defined

final targets for steel chemistry, steel mass and slag composition

The materials are initially distributed according to the different properties and conditions defined

in the practice

A repeated prediction of the process is used to adjust gas mixes, re-arrange additions and add

extra cooling materials with the objective to balance the process within the boundary conditions

of the practice

Figure 5 General layout of process control system [10]

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1.4 Aim of study

Raw materials may not only be a source of valuables but can also contain inclusions tramp

elements and undesired reduction agents. This study attempt to

Understand the benefits and loss in an AOD/CLU process.

Optimize the stainless steel processing in an AOD/CLU process, which compares the time of the

process and the raw material costs. Furthermore to present some aspects of process by the

UTCAS program predictions.

Study the least cost charge materials. The cost of materials amounts to as much as 85 percent of

the total stainless melting and refining operation cost. [1]

2 Experimental set up First of all, stainless steel process templates were set up in UTCAS program. These cover each

stainless steel grades. This study focused on 304, 409,316, 430, 201, and 2205 stainless steel grade. This

is due to that they are the most used in the stainless steel market share, as seen in Figure 6. A second goal

was to optimize the process according to the specific parameter as composition, final weight output, and

temperature. By just changing the targets, and/or the start conditions, the model will automatically

generate an adapted process plan with respect to material distribution and heat control. Anyway, some

raw materials have an uneven composition that will change over all material distribution. In some cases

an operator should adjust input target to compromise with the process condition. Finally, all raw materials

consumption is calculated as a processing cost (detail in 2.6).

Figure 6 Market share of stainless steel grade categories [11]

2.1 Stainless steel and raw materials composition

The studies stainless steel grades are given in Table 3.These data are used as input in the UTCAS

model. The compositions are set to input parameters and the final compositions are set to aim parameters.

Thereafter, the system will calculate (optimize) based on the process and the input parameters that were

assigned. The selected compositions of these stainless steel grades were averaged from various products.

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Table 3 Stainless steel grades analysis composition

Grade Start analysis Final analysis

%C %Si %Cr %Mn %Ni %Mo %N %C %Si %Cr %Mn %Ni %Mo %N

304 1.8 0.1 18 0.5 7 0.2 0.04 0.045 0.5 18 1.2 8.05 0.2 0.04

316 1.7 0.4 17 0.5 10 2 0.04 0.045 0.5 17 1.2 11 2.5 0.07

409 1.3 0.2 10.5 0.2 0.2 0.05 0.02 0.008 0.5 11 <0,015

430 1.7 0.2 16 0.2 0.2 0.05 0.04 0.025 0.5 17

0.04

201 1.7 0.2 20 0.2 4 0.05 0.04 0.08 0.4 17 6.5 5 0.2

2205 2.1 0.2 22 0.7 5 2.7 0.04 0.015 0.5 22 1.5 5.5 3.1 0.16

The raw materials composition is shown in Table 4. The data represents an average from various

suppliers. All of the raw materials compositions including slag formers were assigned in the UTCAS

database before the start of an optimization.

Table 4 Raw materials composition in UTCAS data base

Materials %C %Cr %Ni %Si %Fe %Mn %Mo %Al %P %S %Cu

Stainless steel

304G 0.04 18.15 8.1 0.6 72.11 1.2

Stainless steel

316 0.04 17 10 0.4 1.2 2.5

Stainless steel

430 0.03 17 0.4

Aluminum wire

(Al) 0.1 99.9

Charge Chrome

(ChCr) 7.5 52 3.5 0.029 0.03

Electrolytic

Manganese

(ElMn)

0.001 0.1 99.1

Ferro fragment

(FeFr) 0.1 0.1 99.7 0.1

Ferro

Molybdinum

(FeMo)

0.07 34.44 65.12 0.034 0.04 0.3

Ferro Nickel

(FeNi) 0.05 33.0 0.5 66.45

Ferro Silicon

(FeSi) 0.025 75 23.79 1.17 0.017

High Carbon

Chromium

(HCCR)

7.7 67.0 1.0 24.3

Low Carbon

Ferro

Manganese

(LCFeMn)

0.45 0.8 17.73 81 0.015 0.005

Low Carbon

Silicon

Manganese

0.05 30 9.9 60 0.05

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(LCSiMn)

Nickel Briquette

(NiBS) 0.014 98 1.949

Slag composition

Lime = 96.8% CaO, 2.0% SiO, 1.2% Fe

Dolomite = 60% MgO, 0.19% P, 0.01% SiO2

Fluorspar (CaF2) = 89.9% CaF2, 2.0% Si, 8.1% CaO

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2.2 Final weight controls

The final weight of the stainless steel should be controlled so that it will not exceed the furnace

size. From

Figure 7, the weight will increase during processing due to alloy composition adjustment. In the converter

refining, the main objective is to adjust the composition and mass delivered from EAF. It is often

necessary to aim for a tap mass of between 1-8 % lower than the maximum allowable mass to avoid the

risk of ending up with more steel melt than it is possible to bring to the caster in one ladle after refining. [12]To optimize the mass in a sequence it is necessary to consider the accuracy and predictability of the

production.

Figure 7 Estimated offsets according to some former and present plant metallurgists [10]

This study focused on how to reach mass optimization as described in Table 5.

Table 5 Steel melt mass limitation with furnace size

Plant size (tons) mass limitation (tons)

10 8

30 24

100 72

220 216

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2.3 Temperature controls

Each stainless steel grade has a different temperature, due to composition changes during a

process. Besides, the refractory wear is influenced by the steel temperature. Thus a temperature control is

necessary to avoid a destruction of the refractory. This optimization is possible by means of

Adjusting gas mixture (oxygen, steam, inert gas ratio) over time

Calculated amount of alloys and slag formers

Determining amounts and distribution of additional cooling additions

2.4 Parameters control

The following stainless steel grades were studied: 304, 409, 316,430, 201 and 2205. In addition,

different conditions were studied. The 304 stainless steel grade was studied more extensively. Parameters

such as input materials, alloys and processing were prediction. As seen in the appendix trials condition

were assigned in the UTCAS program. The cases are presented in appendix trials condition, which all

refining variations of the studied stainless steel grades. The starting conditions are different but the

purpose is to optimize the stainless steel process. After optimization of the 304 stainless steel grade

interesting cases were identified as seen in appendix trials condition. Stainless steel grade 409 was

simulated in a similar except for alloy additions. Then set the trial conditions case for 316,430, 201 and

2205 the parameter will change as following.

2.4.1 Trial conditions for stainless steel grade 304

Cases No. 1-3 simulated a case of 8 tons of steel melt, where the amounts of C, Cr input are

varied. However the temperature was constant. These processes do not use an oxygen lance to

increase the temperature during at the first stage, due to the low amount of steel melt.

Cases No. 4-6 simulated a case of 24 tons of steel melt. These cases used the same condition as

cases No. 1-3, but a different furnace size.

Cases No. 7-15 simulated a case of 72 tons of steel melt. The temperature, amount of C were

varied but keep constant of an amount of Cr input and without oxygen lance was used. Also in

cases No. 16-24 the same simulations were done when using an oxygen lance.

Cases No. 25-33 was simulated for a 72 tons steel melt by varying the temperature and amount of

C, but maintaining a constant of Cr input, This process use H2O injection in the processing as an

AOD/CLU.

Cases No.34-36 were simulated for a 72 tons steel melt by maintaining a constant temperature,

but varying amounts of C and Cr.

Cases No. 37-42 were simulated for a 72 tons steel melt by maintaining a constant temperature

and amount of Cr input, but varying the amount of C. In cases No.37-39 the gas mixing was

increased to 1.5 Quantity blowing (Qb). In cases No. 40-42 the gas mixing was decreased to 0.66

Quantity blowing (Qb).The aim was study how gas blowing effect with the processing.


and amount of Cr input but varying the amount of C input. During these processes compressed air

were added during the de-carburizing process, to study the cost difference between a normal

processing and a compressed air injection.

Cases No. 46-48 were simulated for a 72 tons steel melt by maintain a constant temperature and

amount of Cr input but varying the amount of C. During these processes, the de-slagging time

was 3 minutes and the desulphurization time 8 minutes.

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Cases No.49-51 were simulated for a 72 tons steel melt by maintain a constant temperature and

amount of Cr input but varying the amount of C. To investigate the effect of an alloying element

on the process these case study with Charge Chrome (ChCr) input without High Carbon

Chromium (HCCr) input adding in the process. Then compare the processing cost with cases No.

52-54.

Cases No. 52-54 were simulated for a 72 tons steel melt by maintain a constant temperature and

amount of Cr input, but varying the amount of C. To investigate the effect of an alloying element

on the process Charge Chrome (ChCr) and High Carbon Chromium (HCCr) were added to the

process. Also, change source of nickel from Ferro Nickel (FeNi.) to Nickel Briquettes (NiBs).

Cases No.55-57 were simulated for a 72 tons steel melt by maintain a constant temperature, but

varying the amount of carbon and Cr. To investigate alloying effect by adding Ferronickel (FeNi)

input instead of Nickel Briquettes (NiBs). Also add iron of a Low Carbon Ferro-Manganese

(LCFeMn) input instead of a Low Carbon Silicon Manganese (LCSiMn).

Cases No. 58-60 were simulated for a 72 tons steel melt by maintain a constant temperature but

varying the amount of carbon and Cr. In these processes Ferronickel (FeNi) were added instead of

Nickel Briquette (NIBS). Also, Electrolytic Manganese (ElMn) was added instead of a Low

Carbon Ferro-Manganese (LCFeMn).

Cases No.61-63 were simulated for a 216 tons steel melt by maintaining a constant temperature

and amount of Cr. These processes used an oxygen lance to investigate the effect of an oxygen

lance on the process.

2.4.2 Trial conditions of stainless steel grade 409

The trial conditions of stainless steel grade 409 were set up similar to 304 conditions but without

investigation of the alloying effect condition as described in detail.

Cases No. 1-3 were simulated for a case of a 8 tons steel melt amounts of C, Cr input were varied,

but temperature was kept constant. These processes did not use an oxygen lance to increase the

temperature up to the first stage, due to that the amount of steel melt is low.

Cases No. 4-6 were simulated case for a 24 tons steel melt. These cases were similar to cases No.

1-3, but using a different furnace size.

Cases No. 7-15 simulated a case of a 72 tons of steel melt. The temperature and amount of C

were varied but Cr input was kept constant. Without oxygen lance use. Also in cases No. 16-24

the same simulations were done, but the oxygen lance was used in cases No. 16-24.

Cases 25-33 were simulated for a 72 tons steel melt by varying the temperature, amount of C and

amount of Cr. Also H2O injection was used in the process as AOD/CLU.

Cases No. 34-36 were simulated case for a 72 tons steel melt by maintain a constant temperature

but low amount of C with low amount of Cr were set and set high amount of C with high amount

of Cr were set to process are C/Cr = 0.9/9, 1.3/10.5, 1.7/12 to investigate parallel effect of C and

Cr at the same process.


and amount of Cr, but varying amount of C. In cases No.37-39 gas mixing are increased to 1.5

Quantity blowing (Qb). In cases No. 40-42 gas mixing are decreased to 0.66 Quantity blowing

(Qb). To study effect of the gas mixing during the process.

Cases No. 43-45 were simulated for a 72 tons steel melt by maintaining a constant of temperature

and amount of Cr, but varying amount of C. During these processes compressed air was added

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injection during the de-carburizing. To study cost difference between the normal process and the

compressed air injection effect.

Cases No. 46-48 simulated for a 72 tons steel melt by maintain a constant temperature and

amount of Cr input but varying the amount of C. During these processes, the de-slagging time

was 3 minutes and the desulphurization time 8 minutes.

Cases No.49-51 were simulated for a 72 tons steel melt by maintain a constant temperature and

amount of Cr input but varying the amount of C. To investigate the effect of an alloying element

on the process these case study with Charge Chrome (ChCr) input without High Carbon

Chromium (HCCr) input adding in the process. Then compare the processing cost with cases

No.19-21.

Cases No.52-54 were simulated for a 216 tons steel melt by varying amount of C. These

processes were injected an oxygen through the oxygen lance and the initial temperature was set at

1550°c. Then compare with the cases No.55-57, which were not injected oxygen through the

oxygen lance, but set the temperature input at 1650°c to investigate effect of the initial

temperature effect.

2.4.3 Trial condition of stainless steel grade 316

The stainless steel grade 316 was set the process only interesting cases, all of them with a 72 tons size

steel melt detail as seen in appendix trial condition are described in detail.

Cases No.1-3 were simulated by varying amount of Cr and set the refining process without

oxygen injection through oxygen lance.

Cases No. 4-6 were simulated similar to case No. 1-3, but set the oxygen injection through an

oxygen lance.

Case No. 7 was optimized process by using superheat steam during the decarburization process

(CLU).

Case No. 8 was simulated by attempt to increase gas blowing quantity 50% more.

Case No. 9 was simulated by the compressed air injection during the decarburization process.

Case No. 10 was simulated by changing the Cr source from High Carbon Chromium (HCCr) to

Charge Chrome (ChCr), which is not only more amount of chromium but more expensive also.

Cases No. 11-13 were simulated by varying Mo initial composition to investigate initial Mo

effect during the refining process.

Cases No. 14-16 were simulated by varying Ni initial composition to investigate initial Ni

changing during the refining process.


The stainless steel grade 430 was set the process only interesting case, all of them with 72 tons size steel

melt detail as seen in appendix trial condition are described in detail.

Cases No. 1-3 were simulated by varying Cr in the refining process without oxygen lance input.

Cases No. 4-6 were simulated similar to case No. 1-3, but these processes were set with the

oxygen lance injection.

Case No. 7 was optimized process by using superheat steam during the decarburization process

(CLU).

Case No. 8 was simulated by attempt to increase quantity of gas blowing 50% more.

Case No. 9 was simulated by the compressed air injection during the decarburization process.

16

Case No. 10 was simulated by change Cr source form High Carbon Chromium (HCCr) to Charge

Chrome (ChCr), which is not only more amount of chromium but more expensive also.


The stainless steel grade 201 was set the process only interesting case, all of them with a 72 tons size steel


Cases No.1-3 were simulated by varying Ni initial in the refining process without the oxygen

lance input.

Cases No. 4-6 were simulated similar to case No. 1-3, but these processes with the oxygen lance

injection.

Cases No. 7-9 were simulated by changing Ni source form Ferro Nickel (FeNi) to Nickel

Briquettes (NiBs), which is not only more amount of nickel composition but more expensive also.

Cases No.10-12 were simulated by varying Mn input. That the process refining was added Low

Carbon Silicon Manganese (LCSiMn) with the oxygen lance injection.

Cases No.13-15 were simulated by changing Mn source from Low Carbon Silicon Manganese

(LCSiMn) to Electrolytic Manganese (ElMn).

Cases No.16-18 were simulated by changing Mn source from Low Carbon Silicon Manganese

(LCSiMn) to Low Carbon Ferro Manganese (LCFeMn).

Case No. 19 was optimized the process by the superheat steam injection during the

decarburization process (CLU).

Case No. 20 was simulated by increasing the quantity of gas blowing 50% more.

Case No.21 was simulated by adding the compressed air injection during the decarburization

process.


The stainless steel grade 201 was set the process only interesting case, all of them with a 72 tons size steel


Cases No.1-3 were simulated by varying Cr in the refining process without the oxygen lance

input.

Cases No. 4-6 were simulated similar to case No. 1-3, but with the oxygen lance injection.

Cases No.7-9 were simulated by varying Ni initial. The refining processes also use the oxygen

lance injection.

Cases No.10-12 were simulated by varying Mo. The refining processes also use the oxygen lance

injection.

Case No. 13 was optimized process by the superheat steam injection during the decarburization

process (CLU).

Case No. 14 was simulated by increasing the quantity of gas blowing 50% more.

Case No.15 was simulated by adding the compressed air injection during the decarburization

process.

Case No. 16 was simulated by changing Ni source form Ferro Nickel (FeNi) to Nickel Briquettes

(NiBs).

17

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2.5 UTCAS interface set up

The UTCAS interface is easy to use. It can show various parameters on one screen page, as seen in

Figure 8. This contains data such as process profiles, processing times, input-output values, gas supply

layouts, raw material priorities. Also, trend lines for nitrogen-carbon-Cr2O3-temperature.

Figure 8 The UTCAS interface layout

Before setting up a process template it is important to study the alloying during the process. Before all of

the process alloying is done, the main alloying is done before and/or during the decarburization period as

seen in Figure 9. This is described by the raw materials adding rule in the process. [13]

A high carbon containing material should be added early, to promote decarburization. Here an

increased amount of carbon will increase the oxygen consumption.

Si will form SiO2 when added. If Si is added prior to the reduction it will lead to a large

consumption of oxygen, inert gas and slag formers. The added Si will break up the chromium

oxide and through a chemical reaction cause Cr recovery to the melt. Si is cheaper than aluminum

and it would be the preferred element to use unless there are circumstances that will require the

use of aluminum. The most negative effect with a Si addition is probably an increase of the total

slag amount, which in turn seems to have a negative influence on decarburization and lining wear.

In addition, the adding of Si will also affect with de-sulphurization.

Cr, several kinds of ferrochromium are available as alloying materials. Besides the actual content

of chromium composition, the carbon content in each kind is different. The carbon content

composition is related to the price. That means the high carbon ferro-chrome has a higher price

than a lower carbon ferro-chrome. Of course, low carbon content promotes decarburization. This

indicates that chromium should be added late if there is no impact on carbon in the steel melt. This

19

study worked with High Carbon Chromium (HCCr) and Charged Chrome (ChCr). Both of them

have high carbon contents and they should be added early in the process.

Ni will promote decarburization. Thus Ni should be added early. As for chromium alloying, there

are a lot of different allotting materials for nickel. There are various grade materials with different

nickel contents such as Ferro Nickel (FeNi) with 30-40 % Ni or Nickel Briquettes (NiBs) with

over 90% Ni. NiBs was used when there was no need to build up a mass. However, NiBs is much

more expensive than the other nickel source. Thus, the best Ni source should be considered for

each case.

Mn is has a very strong oxygen affinity, so it has a negative impact on decarburization. In

addition, Mn vaporizes when added to the process. Thus, Mn should be added at a late stage of the

process. Also, a Mn source with a low carbon content should be used to avoid affect the carbon

composition. Such as a very useful form of Mn is the Low Carbon Silicon Manganese (LCSiMn)

what is contains 30%Si , 60%Mn and small amounts of iron and the other elements. This material

has a high ability to alloy the steel with manganese without causing negative effect.

High Mo concentrations have a negative impact on decarburization. Thus, high amounts of Mo

should be avoided during decarburization.

Oxide materials such as MoOx and NiOx are reduced during the process.

Slag forming, Calcium oxide (CaO) and Magnesium oxide (MgO) are needed to protect the lining

of the converter. Lime is used as a CaO source and dolomite as a MgO source. Lime and dolomite

are normally added quite early in the process. Calcium fluoride (CAF2) is used to lower the

viscosity of the slag to enchance the reduction of Cr2O3. Fluorspars are used for adding CaF2 and

are normally added during the actual reduction.

Additional of oxygen from a top lance during the first stage of the decarburization is a very

efficient way to boost the oxidation of carbon and to quickly raise the temperature. There is

particularly important in case of large alloy additions where the temperature will drop. The

additional of oxygen from top lance techniques can be more or less eliminated and the total time

will consequently be shorter. A higher temperature of the process will increase the refractory

consumption.

Cooling materials. This technique must be careful controlled with oxygen flows to be able to

maintain a reasonable temperature during decarburization. If the ambition is to reduce the process

time by the means of more aggressively a blowing with oxygen, a cooling material should be used

for cooling purposes. Beneficial cooling materials are materials that are nearly neutral in chemical

composition compared to stainless steel grade produced should be used. Additions should be made

so that it is necessary to compensate with extra chromium, nickel, etc.

Titanium is a valuable element, that is added after the AOD-treatment. For all Ti-stabilized grades

it is essential to have low contents of C and N. A titanium addition is done with the objective to

stabilize the C and N contents, so that they will diffuse to the crystal boundaries. If however the

amount of N and C is high or conditions for growth of TiCN is good a large square shaped TiCN

will form, This will damage the steel surface during rolling. Thus, in the AOD process it is only

important to reach low N and C levels. In fact, the Ti addition is normally based on 5x(%N+%C).

20

Figure 9 Alloying during refining process

21

2.6 Cost model set up

After all the process were optimized by the UTCAS system. The cost models were set up to find out

the processing cost by calculating the optimized results in primary cost and secondary cost. Primary cost,

which do not calculate the profit or loss from EAF processing. The processing cost was calculated based

on the average cost of raw materials as seen in the following

equation (6) and

Table 6.

(6)

This study will calculate the refractory consumption during the process. From the paper “Ferro alloy

design, ferro alloy selection and utilization optimization with particular focus on stainless steel materials”

C-J Rick et. al. has calculated refractory consumption by assume the refractory cost is a function of

inserted oxygen where the average oxygen consumption 2056 nm3 gives a refractory cost of 1500 euro for

the heat as in equation

7) calculated

from refractory life of 100 heats for a 150 ton lining.[14]

7)

Table 6 Raw materials price

Materials Supplier Price (1 $=6.62 sek)

ChCr Xtrata 2.53 $/kg = 16.75 sek/kg

HCCr Vargön 2.134 $/kg= 14.13 sek/kg

FeNi Anglo-American 4 $/kg = 26.48 sek/kg

NiBS Norilsk 17.3$/kg = 114.5 sek/kg

LCCr EWW (Ruukki-group) 4.642$/kg= 30.7 sek/kg

FeMo Climax 29.7$/kg = 196.6 sek/kg

SS304 Outokumpu 4301 2.56 $/kg= 17 sek/kg

SS316 Outokumpu 4401 2.8 $/kg= 18.5 sek/kg

SS430 Outokumpu 4742 0.8 $/kg = 5.3 sek/kg

MSSC Klass 117 0.5 $/kg= 3.31 sek/kg

FeSi Fesil 1.52 $/kg=10.1 sek/kg

LCFeMn Eramet 1.21 $/kg=8.01 sek/kg

LCSiMn Fesil 1.4 $/kg =9.268 sek/kg

ElMn 2.5$/kg =16.55 sek/kg

Al-wire Eramet 2.041 $/kg=13.5 sek/kg

Lime 1 sek/kg

Dolo Nordkalk 1 sek/kg

CaF2 Nordkalk 1.5 sek/kg

O2 lance 1 sek/Nm3

O2 bottom 1 sek/Nm3

22

H2O 0.45 sek/Nm3

N2 0.7 sek/Nm3

Argon 6 sek/Nm3

Compressed Air 0.3 sek/Nm3

In addition, secondary cost models were calculated by concern the profit and loss from earlier processing

for this study is EAF process. Alloying cost will have the following components:

When an alloy (Cr, Ni, Mo and Fe including stainless steel scrap) is added to the converter, the

costs in the EAF by decreases 0.7 sek/kg.

When Fe, Ni and Mo is added in the converter it improves the Fe, Ni and Mo-yield by 1%

compared to the EAF. Thus the cost for these alloys can be decreased by 1%.

When Cr is added in the converter it improves the Cr-yield by 3% compared to the EAF so the

cost for Cr-alloy can be decreased by 3%.

Secondary cost = Primary cost - (weight Cr, Ni, Mo, Fe x 0.7 sek/kg + weight Ni x price cheapest Ni x

0.01 + weight Mo x price cheapest Mo x 0.01 + weight Fe x price cheapest Fe x 0.01 + weight Cr x price

cheapest Cr x 0.03) [15]

23

3. Result This study will discuss the following for each stainless steel grade in;

Comparing of furnace size in term of processing time

Input parameters effected such as C, Cr, temperature, etc.

Alloying effect and limitation.

Processing effect with CLU, compressed air, extra gas blowing and the time fixing.

3.1 Stainless steel grade 304 result

The Table 7 as follow is summary result of stainless steel grade 304 by average.

Table 7 Summary result from UTCAS optimization of stainless steel grade 304

Case No. 1-3 4-6 7-15 16-24 25-33 37-39 40-42 43-45 46-48 49-51 52-54 55-57 58-60 61-63

processing

time 50.3 59.8 65.6 51.86 63.57 51.8 95.2 49.8 45.6 52.26 51.9 52.4 52.06 50.9

primary cost 2925.29 2715.7 2797.6 2791.8 3183.6 3508.3 3637.6 3589.5 8462.3 2964.5 5589.67 2958 2987.04 2954.02

secondary

cost 2769.93 2505.8 2613.9 2588 2989.39 3295.6 3340.4 3370.6 8134.7 2794.3 5327.3 2783 2752.6 2782.2

If cases No.1-3, No. 4-6 and No.7-15 are compared, the smaller furnace size has the less

processing time but not difference too much. Then compare the size of production the

process of the 72 tons steel melt use 15 minutes more but yield the production mass 9

times of 8 tons steel melt. With the 216 tons furnace size provide the production steel

melt 3 times of the 72 tons furnace size but the more investment should be considered.[15]

Then the 72 tons of steel melt is the best size for refining in this study.

If the cases No. 7-15 are compared with No.16-24, the process with oxygen lance

injection has processing time less than the process without oxygen lance injection. Then

the oxygen lance is useful to save the processing time.

If the cases No. 7-15 are compared with No.25-33(CLU). The CLU process can save the

cost of inert gas, as seen in the appendix for the 304 result; page x but with the overall

process cost is higher than for case No. 7-15 due to that the CLU process consume more

FeSi during reduction process. Then in the plant where encounter with inert gas supply

(argon or nitrogen) should be considered the CLU process with higher reduction agent

cost.

Comparing cases No.34-36 as seen in appendix 304 result; page x-xi these case show the

result when the carbon input and the chromium input are low will make the processing

time is less but processing cost is more expensive, due to the process consume more alloy

materials to reach the aim composition. However, when the carbon input and the

chromium input are higher, then the process will need a longer processing time during

decarburization but the process cost is lower.

If the cases No.37-39 (extra gas blowing) are compared to the cases No.40-42 (lower gas

blowing). Cases No.37-39 have a shorter processing time than cases No.40-42, due to the

difference gas blowing quantities. Then a higher gas blowing quantity can save the

processing time. However, the processing cost is almost the same. Therefore, the process

time can be lowered by increasing the gas blowing quantity. However, it should be

avoided do not exceed a temperature rise during the process.

24

Cases No.43-45 were simulated by injecting compressed air. This process has the same

processing time as for cases No.37-39 (extra gas blowing), but the process cost is a little

bit higher. Then, the compressed air input can save the processing time.

For cases No.46-48 the time was fixed during desulphurization to 11 minutes. However

the cost is too high. Due to that UTCAS attempt to use NiBs which is expensive.

Case No.49-51 uses difference carbon values and uses Charged Chrome (ChCr) as an

alloying element, as seen in appendix 304 result; page xiii show the amount carbon input

has affected with the processing cost. The lower carbon input is improved the processing

time but the processing cost is higher, due to the UTCAS attempt to compensate the

carbon by take more ChCr as the carbon source during the refining process.

Cases No. 52-54 were simulated by using ChCr, NiBs and HCCr as alloying elements.

The processing cost is double as high than cases No.49-51. That means that a good

selection of alloying cost will save the processing cost more or less.

Comparing case No. 55-57 (use LCFeMn as Mn source) with case No.58-60 (use ElMn

as Mn source). The Mn source did not change significantly for the 304 stainless steel

cases. This is due to the change of an Mn input with Mn aim composition is low.

Comparing case No.61-63 were simulated of 216 tons steel melt with No.16-24 the

processing time is the same but processing cost a little higher than No.16-24 which is 72

tons steel melt. These cases should be considered in term of furnace investment to

produce the 216 tons plant.


The Table 8 as follow is summary result of stainless steel grade 409 by average.


Case No. 1-3 4-6 7-15 16-24 25-33 37-39 40-42 43-45 46-48 49-51 52-54 55-57

processing

time 55.2 64.4 68.1 60.8 64.6 54.8 97 53.5 45.6 52.1 61.8 74.1

primary

cost 678.16 873.2 721.8 698.15 744.42 1290.1 1429.2 1231.2 1245.9 1382 675.1 678.7

secondary

cost 657.49 822 699.7 677.3 718.65 1196.2 1328.3 1136.1 1152.1 1287.9 651.46 655.8

If the cases No.1-3, No. 4-6 and No.7-15 are compared the smallest furnace size has the

lowest processing time, but the difference is not so large. Then compare the size of

production the process using a 72 tons steel melt uses 15 minutes more but yields a mass

9 times of 8 tons steel melt. Then the 72 tons steel melt is seem to be the best size for

refining in this study.

If the cases No. 7-15 are compared with 16-24, the process with an oxygen lance

injection has a processing time where is less than the process without an oxygen lance

injection. Thus, an oxygen lance is useful to save the processing time.

Cases No. 7-15 are compared with No.25-33(CLU). The CLU process can save the cost

of inert gas as seen in appendix 409 result; page xix. However the overall process cost is

higher than for cases No. 7-15. This is the CLU process consume more FeSi as a

reduction agent during the reduction process.

Comparing case No.34-36 as seen in appendix 409 result ; page xx these cases show the

result when the carbon input and the chromium input are low. This will make the

25

processing time smaller but the processing cost higher. This is due to that alloy materials

are consumed. In opposite, when the carbon and chromium inputs are high, the process

need a longer processing time. This is because a higher carbon amount need more time

during decarburization, but the processing cost is lower.

Comparing cases No.37-39 (extra gas blowing) with cases No.40-42 (lower gas blowing).

The cases No.37-39 have shorter processing time than the cases No.40-42. This is due to

the differences in the gas blowing quantity. Here, a higher gas blowing quantity can save

processing time. However, the processing cost is almost the same. Therefore, the process

can save time by increasing gas blowing quantity. However, this should be avoided not to

exceed the temperature during refining process.

Cases No.43-45 were injected by compressed air. This process has the same processing

time and the processing cost is a little bit higher when compared with cases No.37-39

(extra gas blowing). Then the compressed air input can save the processing time.

However, the air compression system investment should also be taken into account.

Comparing case No.46-48 used a fixed time during de-sulphurization. The processing

cost was different for the cases No. 46-48 of stainless steel grade 304, due to a change of

source from NiBs to FeNi instead. Then the time fixing is useful to optimize the

processing time.

Case No. 49-51where ChCr was added as chromium source are compared with cases No.

19-21where HCCr was added as chromium source. The processes which added ChCr can

improve the processing time by around 10%, but the processing cost is two times

compared to a HCCr adding.

Cases No.52-54 were simulated using a 216 tons steel melt with oxygen injection through

an oxygen lance and set the temperature input at 1550°c with cases No.55-57 were

simulated of 216 tons steel melt without oxygen injection through oxygen lance and set

the temperature input at 1650°c. Obviously, the processing time of the cases No.52-54

are shorter. Thus oxygen injection through oxygen lance can improve the processing

time.


The Table 9 as follow is summary result of stainless steel grade 316.


Case No. 1-3 4-6 7 8 9 10 11 12 13 14 15 16

processing

time 73 74.6 69.8 61.4 75.6 82 81.6 81.6 80.6 80.6 81.2 82.8

primary

cost 3879.2 4007.6 4144.5 4263.3 4182.6 3897.5 8077.9 4068.9 2760.4 4434.9 4206.2 3149.9

secondary

cost 3786.6 3917.1 4037.2 4155.9 4070.9 3808.7 7943.6 3978.9 2672.9 4330.7 4110.9 3089.8

Cases No.1-3 were simulated without using an oxygen injection through oxygen lance and cases

No.4-6 were simulated when using an oxygen injection through an oxygen lance. Overall, the

processing time of cases No.1-3 is shorter than cases No.4-6. Although, during the temperature up

process of cases No.4-6 are shorter than for cases No.1-3. The oxygen injection through the

oxygen lance is made at very high temperatures. Thus, the system attempts to reduce the ratio of

oxygen with nitrogen during the decarburization process for cases No.4-6 as seen for the 316

26

result in the appendix; page xxiv. Therefore, the exceeded temperature is affected with a process

optimization.

Case No.7 was simulated by adding superheated steam as in an AOD/CLU process. The

processing time was almost the same as for cases No.1-3, but this technique reduces the inert gas

consumption as seen in appendix 316 result; page xxv. However, the AOD/CLU process consume

more reduction agent compared to cases No. 1-3.

In case No.8 50% more gas was using. This technique can save the processing time, but the

processing cost is higher than for cases No. 1-3. This is due to that this process has consumed.

Thus, this process can improve the processing time but with the drawback an incresed processing

cost.

In case No.9 compressed air was injected during the decarburization process. This technique can

save an amount of inert gas as seen in appendix 316 result; page xxv. But this technique is used

over a longer time, due to that the decarburization process consumes more time to reach the

aimed carbon composition.

Case No.10 is simulated by setting the chromium source to ChCr instead of HCCr as for the cases

No.4-6. This simulation shows that ChCr had to be added during decarburization after the

temperature up process has ended. Thus, the decarburization process uses a longer time to reach

the aimed carbon content. However, this technique consumes less alloying elements and therefore

this process can lower the processing cost.

Cases No.11-13 which are simulated by varying an amount of Mo initial input. These simulations

have shown as seen in Table 9 the alloying effect with the processing cost when the Mo initial

input is low. The process will consume more Mo source (FeMo), and then made the processing

cost is high.

Cases No. 14-16 are simulated by varying the amount of Ni input. These simulations show the

effect of alloying on the processing cost, Table 9 when the Ni input is low the process will

consume more Ni source (FeNi) then made the processing cost is higher than a high amount Ni

input.


Table 10 summaries the results of stainless steel grade 430.


Case No. 1 2 3 4 5 6 7 8 9 10

processing

time 77.2 74.8 73.2 78.8 77 74.2 71.8 64.2 74.6 82.6

primary

cost 1092.2 830.9 595.8 1263.7 990.1 728.03 1014.1 882.9 1004.5 1152.7

secondary

cost 1050.1 791.7 556.5 1222.1 951.1 689.5 967.9 842.9 964.1 1112.7

Cases No.1-3 were simulated by varying the amounts of Cr input and the process was set without

oxygen injection through the oxygen lance. The processing cost and the processing time are

proportional to the amount of added Cr.

Cases No.4-6 were simulated in a similar way as cases No.1-3 but these processes were set with

oxygen injection through the oxygen lance. The processing cost and the processing time are

proportional with amount of Cr input. With these processes are not different with cases No.1-3,

due to oxygen injection was set too low.

27

Case No.7 was simulated by adding superheated steam as in the AOD/CLU process. The time of

processing was almost the same as for cases No.2, but this technique reduces the inert gas

consumption as seen in appendix 430 result; page xxviii. However, the AOD/CLU process

consumes more reduction agents when compared to cases No.2.

Case No.8 used a 50% higher gas addition. This technique can save the processing time, but the

processing cost is higher than for cases No. 1-3, due to that this process has consumed a higher

amount of gas. Thus, this process can improve the processing time but the drawback is a higher

processing cost compared to case No.2.

Case No.9 simulated injection of compressed air during the decarburization process. This

technique can save an amount of inert gas, as seen in appendix 430 result; page xxviii. But this

technique requires a longer time.

Case No.10 simulated an addition of ChCr as a chromium source instead of HCCr as in case

No.5. This simulation shows the effect an additional with the processing cost. Due to the ChCr is

more expensive than the HCCr.


TTable 11 summaries the results for stainless steel grade 201.


Case No. 1-3 4-6 7-9 10-12 13-15 16-18 19 20 21

processing

time 59.9 59.5 58.2 52.2 53.3 56.9 57 46.6 57

primary

cost 2687.4 2780.8 2896.9 2525.8 2778.1 2391.6 2387.9 2302.1 2379.9

secondary

cost 2611.7 2706 2851.4 2481.5 2719.8 2332.7 2323.9 2243.6 2321.1

Cases No.1, No.2 and No.3 were simulated by varying the amounts of Ni input and the process

was used without an oxygen injection through the oxygen lance, as seen in appendix 201 result;

page xxix. The process which used a low amount of Ni input provided the higher processing cost.

Due to the lower amount of Ni input consume more alloy materials (FeNi).

Cases No.1-3 were simulated by varying the Ni amount and the process was used without oxygen

injection through the oxygen lance as was used in cases No.4-6. Both of these processes have the

same processing times. Due to the steel melt temperature input was set too high during the

temperature up process, the UTCAS program stopped the oxygen injection through the oxygen

lance during a short time when the process temperature reached the temperature process limit.

Cases No.4-6 used FeNi as the Ni source compared cases No.7-9 used NiBs as the Ni source.

Obviously, the cases No.7-9 had higher processing costs, due to that NiBs price is higher than

FeNi.

Cases No.10, No.11 and No.12 were set by varying the Mn input and the process used oxygen

injection through the oxygen lance, as seen in appendix 201 result; page xxx. The process that

used a lower amount of Mn resulted in a higher of processing cost, due to that the lower amount

of Mn consume more alloy materials (LCSiMn).

Cases No.10-12, cases No.13-15 and cases No.16-18 were simulated by using varying amounts of

Mn, but with different Mn sources. Cases No.10-12 used LCSiMn as a Mn source, cases No.13-

28

15 used ElMn as a Mn source and cases No.16-18 used LCFeMn as a Mn source. The processing

cost for cases No.13-15 are the highest, due to that ElMn has the highest prices of Mn source. The

processing cost of case No. 16-18 is the cheapest, due to that LCFeMn has the lowest price.

Nevertheless, the higher price provided a higher alloy composition. This is good for avoiding the

mass build up after refining, due to the furnace size limitation.

Cases No.19 was simulated by adding superheated steam, as used in the AOD/CLU process. The

processing time is almost the same as for the other cases, but this technique reduces the inert gas

consumption as seen in appendix 201; page xxxi. However, the AOD/CLU process consume

more reduction agents compared to the other cases.

Cases No.20 was simulated with a 50% higher gas addition. This technique can lower the

processing time. However, this process consumes more gas, but the processing cost is cheap. Due

to that the overall process is done in a shorter time.

Cases No.21 simulated injection of compressed air during decarburization process and oxygen

was injected through an oxygen lance. This technique can save an amount of inert gas, as seen in

appendix 201; page xxxi. Therefore the processing cost can be lowered.


Table 12 is a summary of the results for stainless steel grade 2205.


Case No. 1-3 4-6 7 8 9 10 11 12 13 14 15 16

processing

time 75 75.3 75.4 74 73.6 74.4 74 74 78.8 59.4 72.2 77

primary

cost 1180.4 1324.2 1030.8 701.58 702.9 1641.7 701.6 701.21 686.5 599.3 675.2 674.6

secondary

cost 1156.1 1297.2 1007.5 690.4 691.7 1618.5 690.4 690.1 672.4 589.3 664.2 665.6

Cases No.1-6 were simulated by varying the amount of Cr input. Either the process was set

without or with oxygen injection through the oxygen lance. The processing cost are proportional

to the amount of added Cr, as seen in appendix 2205; page xxxiii.

Cases No.1-3 were simulated without an oxygen injection through the oxygen lance and cases

No.4-6 simulated using an oxygen injection through the oxygen lance. Both the processing time

and cost for cases No.4-6 is higher than cases No.1-3, due to that the oxygen injection made the

oxidation rapidly at the temperature up state then the UTCAS attempt to balance the amount of Cr

by put more HCCr at decarburization state. Therefore, the processing time has taken the longer

time. The processing cost is higher, due to more the oxygen cost during injection and alloy

materials.

Cases No.7-9 simulated by varying the amounts of added Ni. As seen in Table 12, the alloying

affects the processing cost. When the Ni input is low the process will consume more Ni source

(FeNi). This will make the processing cost higher than a higher amount of added Ni.

Cases No.10-12 simulated by varying the amounts of added Mo. These simulations are shown in

Table 12. The alloying affects the processing cost when the Mo input is low. The process will

consume more Mo (FeMo), and then made the processing cost higher than for a high amount of

added Mo.

Cases No.13 was simulated by adding superheated steam as in the AOD/CLU process. The

processing time is similar to the other cases but this technique reduces the inert gas, as seen in

29

appendix 2205; page xxxv. However, the AOD/CLU process consumes more reduction agent

compared to the other cases.

Cases No.14 simulated a 50% higher gas addition. This technique can lower the processing time.

Even through this process consumes more gas the processing cost is cheap, due to that the overall

process is done during a shorter time.

Cases No.15 simulated injection of compressed air during decarburization process and oxygen

injection through an oxygen lance. This technique can lower the amount of inert gas, as seen in

appendix 2205; page xxxv. Therefore the processing cost is cheap.

Cases No. 16 simulated a changing in Ni source from FeNi to NiBs. The case No.16 is cheaper

than case No.8. This is due to that the NiBs addition is less than the FeNi addition to reach the

aimed composition. Thus the processing cost is cheaper.

4. Discussion Each stainless steel grade requires a different optimization method. The optimization considers

parameters such as initial steel melt composition, final steel melt composition, stainless steel grade,

limitation of steel plant and etc. The result and discussion for each technique will be described below.

4.1The oxygen injection through the oxygen lance

This technique can save the processing time in some simulation as for stainless steel grade 304 and 409.

But some stainless steel grade had a too high initial temperature and the gap between the initial

temperature and the final temperature is low. Thus this technique is less effecting with respect to the

overall process as for stainless steel grades 316,201 and 2205.

4.2 The initial steel melt composition

The effect of the initial steel melt composition both the processing time and the processing cost were

studied. The most effect i.e. alloy found in this study is Ni. For example the Ni initial composition was set

too low when compared to the final composition such as from 1.5 to 5%Ni. For a plant size of 72 tons

steel melt this will lead to a huge consumption of alloy material (FeNi). Approximate 40% of initial steel

melt and encounter with mass built up from amount of Fe in FeNi. In addition, the initial steel mass must

be set with a low initial mass, due to plant size limitation. Then, the blowing gas should be lowed, which

cause a too long processing time and a high cost. Besides, another alloying materials selection can solve

this problem such as use NiBs instead of FeNi. However the processing cost will increase too much.

4.3 Superheat steam injection (AOD/CLU)

This technique is suitable for the producer who encounters problems with inert gas supply. Furthermore,

this technique requires an extra system investment (superheat steam supply) including a reduction agent

cost. However, this technique can decrease the processing time more or less for every stainless steel

grade.

4.4 Compressed air injection

This technique can save the processing cost, due to the low cost of compressed air. Also, this technique

requires an adjustment of the gas ratio. Otherwise, this technique will have negative effect on the

processing time, as for stainless steel grade 316. Here, the compressed air injection together with the

oxygen blowing through the bottom-tuyeres was not sufficient.

30

4.5 Alloying materials selection

This technique relate to the other techniques such as the blowing plan, the initial composition, the initial

temperature, and the processing cost. According to the specific stainless steel grade some alloy materials

should not be used during the process. For example, stainless steel grade 201 which focus on the final Mn

composition as in cases No.10-12. Here, the LCSiMn was added and the final Si composition was

increased over the aimed composition. Instead the LCFeMn or ElMn should be used for these cases.

4.6 Extra blowing

This technique improves the processing time for every cases, due to that the extra blowing has positive

effects. Due to that the activity during the process such as entropy of steel melt, velocity of circulation are

increased. However, this technique requires a higher gas consumption during the process, so the

processing cost will higher than for a lower the gas blowing. However, for stainless steel grade 2205 this

technique has a positive effect on the overall processing cost, due to that the processing time is shortened

compared to standard process.

4.7 The time adjustment

This technique was simulated with stainless steel grade 304 and 409. Stainless steel grade 304 uses NiBs

as the alloying material while grade 409 uses FeNi as the alloying material. This technique has a positive

effect on the processing time for both stainless steel grades. However for stainless steel grade 304 it has a

negative affect with the processing cost, due to that the Ni source is expensive. On the other hand, the

technique has a positive effect on the stainless steel grade 409 processing cost. Thus, this technique

relates to the alloying selection technique also.

5. Conclusion

The AOD optimization is done by many factors as in the result and discussion. The optimized process

will vary upon each situation such as

The input parameters and amount C, Cr as well as on temperature, steel melt mass, alloys and

other.

Alloying materials selection

Processing strategy selection

Refining limitation, due to some input value is too low the process cannot be reached the aiming

value. Then the starting parameters are the one important factor to avoid the loss of raw materials

to refine the stainless steel.

31

6. Future work This study did not focus on the off gas and the heat loss during the process. Because those values are

more complicate than the basic setting and require much more detail calculations. Anyway, those values

can be calculated by the UTCAS program. In a future work, the next study will include these aspects.

7. Reference [1] Richard J. Choulet: Stainless Steel Refining,1997, page 1-5

[2] http://www.matweb.com, 2013

[3] http://agmetalminer.com, 2013

[4] M. Engholm, C-J Rick: Optimized AOD gas administration- a lean process for a green world,

Baosteel BAC 2010, page 1

[5] CRE pic

[6] www.keytometals.com, 2008

[7] K Beskow, J-A Van Der Linde and C-J Rick: Steam as process gas brings economic benefits to

Columbus Stainless, page 1

[8] C-J Rick: Strategies for Use of Superheated Steam During stainless Steel Refining in Converters,2010

, Vol. 1, page 1107

[9] C. Rick, M. Engholm: Control and optimization of material additions throughout the AOD refining

cycle, Steelsim 09,2009

[10] C. Rick, M. Engholm: Stainless steel refining with the AOD-process,2011,page 48

[11] http://www.steelorbis.com,2013

[12] C. Rick et al: Increased stainless steel melt shop yield by improved converter tap weight

management,2011,page 2

[13] UHT distributed papers: AOD-process exercises with UTCAS simulation,2011

[14] C-J Rick et. al.: Ferro alloy design, ferro alloy selection and utilization optimization with particular

focus on stainless steel materials,2012

[15] Suggestion form metallurgists and process consultants: C-J Rick

http://www.matweb.com/

http://agmetalminer.com/

http://www.keytometals.com/

http://www.steelorbis.com,2013/

i

Appendix trials condition

304 condition

Size 8 tons 24tons 72 tons 216 tons

Case No. 1-3 4-6 7-15 16-24 25-33 34-36 37-42 43-45 46-48 49-51 52-54 55-57 58-60 61-63

Temp. maintain maintain vary vary vary maintain maintain maintain maintain maintain maintain maintain maintain maintain

%Cr maintain maintain maintain maintain maintain vary maintain maintain maintain maintain vary vary vary maintain

%C vary vary vary vary vary vary vary vary vary vary vary vary vary vary

O2lance off off off on off on on on on on on off off on

H2O on on off off on off off off off off off off off off

Air off off off off off off off on off off off off off off

O2-Bottom on on on on on on vary on on on on on on on

N on on on on on on vary on on on on on on on

Ar on on on on on on vary on on on on on on on

CHCr off off off off off off off off on on on off off off

HCCr on on on on on on on on on off on on on on

NiBs off off off off off off off off off off on off off off

LCSiMn on on on on on on on on on on on off off on

ElMn off off off off off off off off off off off off on off

LCFeMn off off off off off off off off off off off on off off

ii

409 condition

Size 8 tons 24tons 72 tons 216 tons

Case No. 1-3 4-6 7-15 16-24 25-33 34-36 37-42 43-45 46-48 49-51 52-57

Temp. maintain maintain vary vary vary maintain maintain maintain maintain maintain vary

%Cr maintain maintain vary vary vary vary maintain maintain maintain maintain maintain

%C vary vary vary vary vary vary vary vary vary vary vary

O2lance off off off on off on on on on on on

H2O on on off off on off off off off off off

Air off off off off off off off on off off off

O2-Bottom on on on on on on vary on on on on

N on on on on on on vary on on on on

Ar on on on on on on vary on on on on

CHCr off off off off off off off off off on off

HCCr on on on on on on on on on off on

Ni off off on on on on on on off off off

LCSiMn on on on on on on on on on on on

ElMn off off off off off off off off off off off

LCFeMn off off off off off off off off off off off

iii

316 condition

Case No. 1-3 4-6 7 8 9 10 11-13 14-16

Temp. maintain maintain maintain maintain maintain maintain maintain maintain

start %Cr vary vary maintain maintain maintain maintain maintain maintain

start %C maintain maintain maintain maintain maintain maintain maintain vary

start % Mo maintain maintain maintain maintain maintain maintain vary maintain

start %Ni maintain maintain maintain maintain maintain maintain maintain vary

O2lance off on off off on on on on

H2O off off on off off off off off

Air off off off off on off off off

O2-Bottom on on on 1.5Qb on on on on

N on on on 1.5Qb on on on on

Ar on on on 1.5Qb on on on on

CHCr off off off off off on off off

HCCr on on on on on off on on

FeNi on on on on on on on on

LCSiMn on on on on on on on on

ElMn off off off off off off off off

LCFeMn off off off off off off off off

FeMo on on on on on on on on

iv

430 condition

Case No. 1-3 4-6 7 8 9 10

Temp. maintain maintain maintain maintain maintain maintain

start %Cr vary vary maintain maintain maintain maintain

start %C maintain maintain maintain maintain maintain maintain

start % Mo maintain maintain maintain maintain maintain maintain

start %Ni maintain maintain maintain maintain maintain maintain

O2lance off on off off on on

H2O off off on off off off

Air off off off off on off

O2-Bottom on on on 1.5Qb on on

N on on on 1.5Qb on on

Ar on on on 1.5Qb on on

CHCr off off off off off on

HCCr on on on on on off

FeNi on on on on on on

LCSiMn on on on on on on

ElMn off off off off off off

LCFeMn off off off off off off

FeMo on on on on on on

v

201 condition

Case No. 1-3 4-6 7-9 10-12 13-15 16-18 19 20 21

Temp. maintain maintain maintain maintain maintain maintain maintain maintain maintain

start %Cr maintain maintain maintain maintain maintain maintain maintain maintain maintain

start %C maintain maintain maintain maintain maintain maintain maintain maintain maintain

start % Mo maintain maintain maintain maintain maintain maintain maintain maintain maintain

start %Ni vary vary vary maintain maintain maintain maintain maintain maintain

start %Mn maintain maintain maintain vary vary vary maintain maintain maintain

O2lance off on on on on on off off on

H2O off off off off off off on off off

Air off off off off off off off off on

O2-Bottom on on on on on on on 1.5Qb on

N on on on on on on on 1.5Qb on

Ar on on on on on on on 1.5Qb on

CHCr off off off off off off off off off

HCCr on on on on on on on on on

FeNi on on off on on on on on on

NiBs off off on off off off off off off

LCSiMn on on on on off off on on on

ElMn off off off off on off off off off

LCFeMn off off off off off on off off off

FeMo on on on on on on on on on

vi

2205 condition

Case No. 1-3 4-6 7-9 10-12 13 14 15 16

Temp. maintain maintain maintain maintain maintain maintain maintain maintain

start %Cr vary vary maintain maintain maintain maintain maintain maintain

start %C maintain maintain maintain maintain maintain maintain maintain maintain

start % Mo maintain maintain maintain vary maintain maintain maintain maintain

start %Ni maintain maintain vary maintain maintain maintain maintain vary

start %Mn maintain maintain maintain maintain maintain maintain maintain maintain

O2lance off on on on off off on on

H2O off off off off on off off off

Air off off off off off off on off

O2-Bottom on on on on on 1.5Qb on on

N on on on on on 1.5Qb on on

Ar on on on on on 1.5Qb on on

CHCr off off off off off off off off

HCCr on on on on on on on on

FeNi on on on on on on on off

NiBs off off off off off off off on

LCSiMn on on on on on on on on

ElMn off off off off off off off off

LCFeMn off off off off off off off off

FeMo off off off off on off off off

vii

Appendix 304 result

304 case No. 1 2 3 4 5 6

TempUp Time 16.2 16.6 22.6 21.8 26.4 31

Decarb Time 11 11 11.4 12 12.4 13.4

Reduction time 5.2 5.2 5.2 5.2 5.2 5.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 9.4 9.4 9.4 9.4 9.4 9.4

ChCr 0 0 0 0 0 0

HCCr 21.534 22.376 18.913 16.205 16.266 16.398

FeNi 45.823 47.239 44.131 42.537 42.697 43.045

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 50.08 49.725 50.435 48.614 48.797 49.195

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 5.258 0 0 0 0 0

FeSi 15.274 22.376 21.435 16.205 16.266 12.299

LCSiMn 10.392 10.442 11.096 10.047 10.41 10.413

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 52.333 38.91 36.061 24.55 23.056 21.154

Dolo 27.293 20.636 19.292 13.126 12.402 11.438

CaF2 9.64 7.334 6.935 4.74 4.473 4.182

O2-Lance 0 0 0 0 0 0

O2-bottom 20.745 18.684 24.65 21.584 25.602 29.763

H2O 0 0 0 0 0 0

N2 10.504 8.764 9.646 8.426 9.141 11.118

Ar 4.783 4.749 4.817 7.543 7.832 7.551

Compressed air 0 0 0 0 0 0

Processing time 48 48.4 54.8 54.6 59.6 65.2

primary cost (sek/ton) 2914.27 2972.84 2888.78 2687.59 2727.89 2731.6

secondary cost (sek/ton) 2796.87 2738.85 2774.08 2450.08 2621.47 2445.87

viii

304 case No. 7 8 9 10 11 12 13 14 15

TempUp Time 29.2 32.8 36.4 27.2 31.2 36 21.4 26 28.6

Decarb Time 11.4 12.2 13 12 12.8 13.6 14 14.8 23

Reduction time 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 9.4 9.4 9.4 10 10.6 9.4 11.4 11 11.6

ChCr 0 0 0 0 0 0 0 0 0

HCCr 19.249 16.325 13.354 18.6 15.727 12.794 17.936 15.104 12.026

FeNi 45.371 42.951 40.492 44.762 42.379 39.971 44.131 41.797 39.21

Ni 0 0 0 0 0 0 0 0 0

LCCr 0 0 0 0 0 0 0 0 0

FeMo 0 0 0 0 0 0 0 0 0

SS304 49.889 49.976 49.973 50.045 50.103 49.739 49.975 50.023 49.879

SS316 0 0 0 0 0 0 0 0 0

SS430 0 0 0 0 0 0 0 0 0

MSSC 0 0 0 0 0 0 0 0 0

FeSi 26.081 23.6 21.266 20.24 18.26 16.248 14.007 12.478 9.394

LCSiMn 11.835 11.717 11.605 11.733 11.607 11.523 11.647 11.547 11.444

Alum 0 0 0 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0 0 0 0

ElMn 0 0 0 0 0 0 0 0 0

Lime 68.209 61.567 55.359 53.033 47.682 42.278 36.857 32.71 24.565

Dolo 30.363 27.445 24.709 23.674 21.308 18.928 16.534 14.715 11.126

CaF2 10.241 9.273 8.357 8.007 7.223 6.425 5.636 5.03 3.824

O2-Lance 0 0 0 0 0 0 0 0 0

O2-bottom 28.143 31.507 34.72 24.6 28.024 31.623 20.681 24.406 17.618

H2O 0 0 0 0 0 0 0 0 0

N2 12.367 13.471 14.503 14.635 16.066 17.121 14.701 16.102 16.432

Ar 5.46 5.47 5.619 5.894 6.319 6.041 6.858 6.898 7.449

Compressed air 0 0 0 0 0 0 0 0 0

Processing time 61.4 65.8 70.2 60.6 66 70.4 58.2 63.2 74.6

primary cost (sek/ton) 3049.5

6

2933.1

7

2815.5 2920.8

3

2815.8

9

2699.0

1

2780.9

6

2684.3

5

2560.3

secondary cost (sek/ton) 2930.6

6

2628.3

7

2708.7 2657.0

5

2707.6

3

2404.1 2672.5 2432.5 2464.0

9

ix

304 case No. 16 17 18 19 20 21 22 23 24

TempUp Time 14.2 15.8 17.4 11.4 13 14.8 8.6 10.6 11.6

Decarb Time 13.4 14.4 15.4 15.2 16 17.4 16.8 18.4 23

Reduction time 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 9.4 9.8 10.6 10.6 11.4 12.2 10.4 10.8 11.6

ChCr 0 0 0 0 0 0 0 0 0

HCCr 19.543 16.419 13.267 18.55 15.498 12.374 17.694 14.824 12.031

FeNi 45.642 43.027 40.411 44.695 42.137 39.549 43.888 41.51 39.214

Ni 0 0 0 0 0 0 0 0 0

LCCr 0 0 0 0 0 0 0 0 0

FeMo 0 0 0 0 0 0 0 0 0

SS304 50.003 50.048 49.959 49.985 49.949 49.939 49.999 50.062 49.954

SS316 0 0 0 0 0 0 0 0 0

SS430 0 0 0 0 0 0 0 0 0

MSSC 0 0 0 0 0 0 0 0 0

FeSi 26.115 22.789 19.232 19.518 16.198 12.859 11.986 10.04 9.394

LCSiMn 11.89 11.747 11.602 11.719 11.571 11.458 11.625 11.542 11.448

Alum 0 0 0 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0 0 0 0

ElMn 0 0 0 0 0 0 0 0 0

Lime 78.782 66.981 55.885 54.4 43.872 33.514 31.638 26.422 24.561

Dolo 35.03 29.834 24.938 24.271 19.633 15.065 14.236 11.945 11.115

CaF2 11.806 10.065 8.438 8.22 6.66 5.146 4.861 4.102 3.83

O2-Lance 14.001 15.615 17.186 11.197 12.787 14.582 8.4 10.413 11.39

O2-bottom 15.77 17.242 18.771 13.926 15.426 17.101 12.125 14.07 17.662

H2O 0 0 0 0 0 0 0 0 0

N2 11.831 12.987 14.002 12.666 13.544 15.059 12.652 14.343 16.457

Ar 5.473 5.756 6.3 6.304 6.854 7.408 6.789 7.075 7.443


Processing time 48.4 51.4 54.8 48.6 51.8 55.8 47.2 51.2 57.6

primary cost (sek/ton) 3092.5 2949.77 2804.7 2916.98 2778.93 2643.1 2739.27 2638.7 2562.21

secondary cost (sek/ton) 2791.66 2837.27 2480.45 2803.72 2500.76 2543.8 2507.6 2537.7 2288.94

x

304 case No. 25 26 27 28 29 30 31 32 33 34

TempUp Time 30 34 37.6 25.4 29 33 20.4 25 30 14.2

Decarb Time 9.6 10.2 11 11 11.6 12.4 12.6 13 13.2 14

Reduction time 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 10.8 11 11 11 11.2 11.4 11.4 11.4 11.4 9.8

ChCr 0 0 0 0 0 0 0 0 0 0

HCCr 19.709 16.849 13.903 19.137 16.213 14.414 18.476 18.018 17.921 56.93

FeNi 45.807 43.448 41.015 45.272 42.723 41.245 44.524 44.185 44.153 54.014

Ni 0 0 0 0 0 1.857 0 4.31 9.529 0

LCCr 0 0 0 0 0 0 0 0 0 0

FeMo 0 0 0 0 0 0 0 0 0 0

SS304 50.001 50.004 50.002 49.994 54.404 54.439 54.378 54.469 54.429 49.988

SS316 0 0 0 0 0 0 0 0 0 0

SS430 0 0 0 0 0 0 0 0 0 0

MSSC 0 0 0 0 0 1.857 0 4.31 9.529 0

FeSi 30.542 28.502 26.445 25.414 23.558 21.704 20.193 19.348 19.431 21.925

LCSiMn 11.903 11.807 11.709 11.818 11.668 11.822 11.667 11.92 11.925 12.039

Alum 0 0 0 0 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0 0 0 0 0

ElMn 0 0 0 0 0 0 0 0 0 0

Lime 79.835 74.353 68.794 66.478 61.472 56.102 52.911 50.284 50.51 58.944

Dolo 35.501 33.072 30.626 29.607 27.396 25.03 23.611 22.467 22.561 26.271

CaF2 11.959 11.154 10.334 9.985 9.257 8.468 7.986 7.609 7.645 8.873

O2-Lance 0 0 0 0 0 0 0 0 0 13.997

O2-bottom 27.312 30.747 33.923 23.619 26.75 30.28 19.653 23.573 27.799 15.766

H2O 7.289 7.79 8.411 8.543 8.935 9.535 9.843 10.19 10.293 0

N2 6.445 7.112 7.711 5.677 6.264 6.93 4.827 5.599 6.426 12.427

Ar 5.361 5.5 5.5 5.499 5.626 5.765 5.757 5.766 5.761 5.749

Compressed air 0 0 0 0 0 0 0 0 0 0

Processing time 61.8 66.6 71 58.8 63.2 68.2 55.8 60.8 66 49.4

primary cost (sek/ton) 3127.2 3019.6 2905.8 3004.6 2965.9 3121.1 2946.79 3458.6 4102.4 3770.32

secondary cost (sek/ton) 3004.3 2715.1 2794.5 2742.4 2849.5 2819.4 2829.46 3187.7 3961.7 3438.2

xi

304 case No. 35 36 37 38 39 40 41 42

TempUp Time 15 15.4 20.6 22.2 23.6 57.4 60.2 60.2

Decarb Time 14.8 15.8 8.6 8.6 9.4 12.8 14.8 13.8

Reduction time 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 10.4 11.2 9.4 9.4 9.4 10.4 10 12

ChCr 0 0 0 0 0 0 0 0

HCCr 31.942 0 56.727 31.297 6.121 56.267 31.314 6.125

FeNi 53.996 50.381 54.641 54.665 54.675 54.6 54.696 54.707

Ni 0 0 0 0 0 0 0 0

LCCr 0 0 0 0 0 0 0 0

FeMo 0 0 0 0 0 0 0 0

SS304 49.996 49.691 50.053 50.074 50.084 50.015 50.103 50.113

SS316 0 0 0 0 0 0 0 0

SS430 0 0 0 0 0 0 0 0

MSSC 28.317 47.924 1.988 30.072 58.153 0 27.571 55.278

FeSi 19.749 16.84 21.022 19.793 18.503 30.565 28.392 26.992

LCSiMn 12.305 12.147 12.388 12.338 12.298 12.129 12.359 12.292

Alum 0 0 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0 0 0

ElMn 0 0 0 0 0 0 0 0

Lime 52.163 43.549 56.31 52.342 48.206 71.925 71.021 70.089

Dolo 23.276 19.49 25.11 23.354 21.536 31.996 31.593 31.182

CaF2 7.888 6.612 8.495 7.901 7.304 10.781 10.661 10.524

O2-Lance 14.799 15.106 0 0 0 0 0 0

O2-bottom 16.713 17.119 27.044 28.847 30.638 32.327 34.6 35.988

H2O 0 0 0 0 0 0 0 0

N2 13.085 13.889 16.803 17.422 18.946 13.393 14.21 16.173

Ar 6.166 6.681 8.05 8.054 8.055 4.896 4.899 5.652

Compressed air 0 0 0 0 0 0 0 0

Processing time 51.6 53.8 50 51.6 53.8 92 96.4 97.4

primary cost (sek/ton) 3303.3 2971.42 3779.08 3507.45 3238.6 3900.33 3638.45 3374.13

secondary cost (sek/ton) 3150.7 2636.35 3626.93 3177.6 3082.43 3546.43 3480.09 2994.8

xii

304 case No. 43 44 45 46 47 48

TempUp Time 14.4 15 16.2 12.2 13.6 15.8

Decarb Time 14.6 15.4 14.6 14.8 16 16

Reduction time 5.2 5.2 5.2 5.2 5.2 5.2

Deslagging time 6.2 6.2 6.2 3 3 3

Desulph time 8.4 8.4 8.4 8 8 8

ChCr 0 0 0 0 0 0

HCCr 57.876 31.15 6.093 23.961 20.411 20.24

FeNi 56.718 54.409 54.423 0 0 0

Ni 0 0 0 57.962 53.948 59.518

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 54.362 54.354 54.381 50.063 50.055 49.736

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 0 29.586 57.594 41.344 38.32 43.989

FeSi 22.944 20.199 18.681 21.238 17.682 14.797

LCSiMn 12.65 12.28 12.242 12.099 11.971 11.895

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 61.638 53.399 48.676 57.308 46.134 38.684

Dolo 27.463 23.827 21.741 25.56 20.634 17.339

CaF2 9.274 8.058 7.367 8.636 6.994 5.899

O2-Lance 14.089 14.753 15.953 12.015 13.415 15.518

O2-bottom 14.254 15.01 15.828 14.415 15.873 17.576

H2O 0 0 0 0 0 0

N2 5.209 5.494 5.658 12.619 13.759 14.056

Ar 4.41 4.43 4.431 6.035 6.591 6.825

Compressed air 9.31 9.799 9.223 0 0 0

Processing time 48.8 50.2 50.6 43.2 45.8 48



xiii

304 case No. 49 50 51 52 53 54 55 56 57

TempUp Time 11.8 13.2 15 10.6 12.6 14.8 11.4 13.8 15.8

Decarb Time 15.4 16.6 17.4 16.2 16.6 17.6 15.8 15.6 17.2

Reduction time 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 10.8 10.2 12.2 10.6 10.4 12.2 10.6 11 11.8

ChCr 26.634 22.212 17.785 17.225 17.058 16.913 0 0 0

HCCr 0 0 0 17.225 17.058 16.913 18.801 18.872 18.992

FeNi 46.472 43.635 40.807 0 0 0 45.31 45.481 45.769

Ni 0 0 0 25.024 31.322 37.415 0 0 0

LCCr 0 0 0 0 0 0 0 0 0

FeMo 0 0 0 0 0 0 0 0 0

SS304 49.527 49.884 49.866 50.047 50.048 50.072 49.549 49.736 50.051

SS316 0 0 0 0 0 0 0 0 0

SS430 0 0 0 0 0 0 0 0 0

MSSC 0 0 0 11.594 17.892 23.979 0 0 0

FeSi 18.867 15.339 12.12 17.588 14.932 12.407 22.022 22.105 19.464

LCSiMn 11.735 11.626 11.525 11.455 11.442 11.447 0 0 0

Alum 0 0 0 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0 9.635 9.671 9.732

ElMn 0 0 0 0 0 0 0 0 0

Lime 52.952 42.859 33.839 48.602 39.886 33.312 54.394 54.599 54.945

Dolo 23.635 19.095 15.14 21.715 17.878 14.98 24.279 24.371 20.855

CaF2 7.993 6.485 5.167 7.354 6.075 5.119 8.217 8.248 8.3

O2-Lance 11.49 12.97 14.76 10.41 12.412 14.621 11.099 13.528 15.616

O2-bottom 14.283 15.841 17.362 13.582 15.39 17.375 14.042 15.869 17.899

H2O 0 0 0 0 0 0 0 0 0

N2 12.66 13.441 14.951 13.093 13.388 15.072 12.913 13.376 15.135

Ar 6.383 6.463 7.397 6.462 6.623 7.427 6.249 6.549 7.146


Processing time 49.4 51.4 56 48.8 51 56 49.2 51.8 56.2

primary cost (sek/ton) 3136.49 2962.4 2794.8 4869.56 5593.17 6306.28 2923.2 2965.7 2985.13

secondary cost (sek/ton) 3016.7 2675.1 2691.1 4588.77 5444.39 5948.83 2807.8 2670.7 2870.5

xiv

304 case No. 58 59 60 61 62 63

TempUp Time 11.4 13.6 16 10.2 12.6 14.8

Decarb Time 14.8 16.2 16.4 18.4 18.4 18.6

Reduction time 5.2 5.2 5.2 5.4 5.4 5.4

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 10.6 11.2 11.8 7.8 8.2 9

ChCr 0 0 0 0 0 0

HCCr 18.68 18.648 18.63 19.472 18.935 18.818

FeNi 45.025 44.95 44.906 46.363 49.999 50.003

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 49.997 49.913 49.865 50.072 50.073 50.081

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 0 0 0 0 1.678 7.568

FeSi 23.61 22.184 20.084 15.586 14.696 12.428

LCSiMn 0 0 0 11.827 11.679 11.672

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 6.944 6.932 6.926 0 0 0

Lime 54.261 54.17 54.117 34.48 31.249 26.219

Dolo 24.221 24.18 22.162 10.793 9.783 8.212

CaF2 8.194 8.18 8.172 5.225 4.743 3.997

O2-Lance 11.199 13.377 15.757 10.014 12.418 14.624

O2-bottom 13.919 15.922 17.785 13.226 14.948 16.749

H2O 0 0 0 0 0 0

N2 12.28 13.826 14.527 15.415 16.098 16.705

Ar 6.305 6.711 7.12 4.145 4.33 4.702


Processing time 48.2 52.4 55.6 48 50.8 54



xv

Appendix 409 result

409 case No. 1 2 3 4 5 6

TempUp Time 13.2 13.2 18.4 17 18 19

Decarb Time 13.2 13.2 20 17 21.4 26.4

Reduction time 2.2 2.2 2.2 2.2 2.2 2.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 16.4 16.4 16.4 16.4 16.4 16.4

ChCr 0 0 0 0 0 0

HCCr 8.21 8.21 7.507 13.764 13.763 13.763

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 0 0 4.754 37.872 41.748 45.543

FeSi 19.634 19.634 20.416 15.599 15.64 15.848

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 44.407 44.407 42.664 27.57 27.568 28.11

Dolo 28.858 28.858 28.026 19.52 19.519 19.811

CaF2 26.743 26.743 26.024 18.06 18.059 18.267

O2-Lance 0 0 0 0 0 0

O2-bottom 16.556 16.556 26.362 19.929 23.514 27.226

H2O 0 0 0 0 0 0

N2 0 0 0 0 0 0

Ar 16.954 16.954 19.355 21.439 23.256 25.549


Processing time 51.2 51.2 63.2 58.8 64.2 70.2

primary cost 646.82 646.82 740.82 821.54 871.09 926.98

secondary cost 627.33 627.33 717.79 773.22 819.9 872.86

xvi

409 case No. 7 8 9 10 11 12

TempUp Time 26.4 30.8 35.4 20.6 25.6 30.4

Decarb Time 13.2 13.4 13.4 15.8 15.4 15.4

Reduction time 2.2 2.2 2.2 2.2 2.2 2.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 16.4 16.4 16.4 16.4 16.4 16.4

ChCr 0 0 0 0 0 0

HCCr 7.283 7.283 7.269 7.283 7.283 7.283

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 0.709 4.878 9.062 2.377 6.463 10.549

FeSi 23.592 22.961 22.491 17.16 16.91 16.691

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 48.048 46.547 45.017 32.427 31.677 30.981

Dolo 29.701 28.923 28.116 21.6 21.21 20.849

CaF2 25.365 24.712 24.058 18.611 18.278 17.985

O2-Lance 0 0 0 0 0 0

O2-bottom 24.523 27.881 31.335 20.63 24.218 27.826

H2O 0 0 0 0 0 0

N2 0 0 0 0 0 0

Ar 23.361 24.606 25.754 24.054 25.069 26.264


Processing time 64.4 69 73.6 61.2 65.8 70.6

primary cost 773.4 808.86 845.83 656.66 697.56 740.13

secondary cost 751.28 784.11 818.35 637.81 675.8 715.62

xvii

409 case No. 13 14 15 16 17 18

TempUp Time 4.8 5 5.4 13.2 16.6 16.8

Decarb Time 35.2 39.4 43.6 15.6 15.2 16.2

Reduction time 2.2 2.2 2.2 2.2 2.2 2.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 16.4 16.4 16.4 16.4 16.4 16.4

ChCr 0 0 0 0 0 0

HCCr 7.282 7.283 7.284 7.283 7.29 7.282

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 3.544 7.603 11.648 0.569 3.416 9.487

FeSi 13.286 13.08 12.941 20.615 21.081 17.867

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 21.389 20.933 20.572 49.427 60.499 41.236

Dolo 15.871 15.637 15.443 30.408 36.158 26.173

CaF2 13.828 13.636 13.469 25.955 30.756 22.414

O2-Lance 0 0 0 8.989 10.797 12.583

O2-bottom 18.284 21.998 25.679 15.315 17.876 18.165

H2O 0 0 0 0 0 0

N2 0 0 0 0 0 0

Ar 29.997 30.693 31.617 21.691 22.164 23.03


Processing time 64.8 69.2 73.8 53.6 56.6 57.8

primary cost 616.46 657.37 700.2 734.27 806.35 772.02

secondary cost 599.47 637.54 677.5 714.3 783.99 747.46

xviii

409 case No. 19 20 21 22 23 24

TempUp Time 10.8 16 21 2.2 2.6 2.6

Decarb Time 17 17 16.8 37.4 41.2 45.8

Reduction time 2.2 2.2 2.2 2.2 2.2 2.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 16.4 16.4 16.4 16.4 16.4 16.4

ChCr 0 0 0 0 0 0

HCCr 7.296 7.278 7.276 7.29 7.291 7.278

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 2.261 6.918 11.254 3.548 7.609 11.659

FeSi 14.831 14.562 14.324 13.292 13.098 12.92

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 33.733 27.74 24.587 21.4 20.943 20.545

Dolo 22.276 19.159 17.519 15.87 15.634 15.429

CaF2 19.169 16.58 15.204 13.832 13.625 13.461

O2-Lance 6.791 6.388 6.387 1.796 1.796 1.996

O2-bottom 13.626 17.523 21.114 16.862 20.494 24.085

H2O 0 0 0 0 0 0

N2 0 0 0 0 0 0

Ar 22.376 23.651 24.839 30.889 31.449 32.458


Processing time 52.6 57.8 62.6 64.4 68.6 73.2

primary cost 624.18 656.06 693.7 624.67 664.28 707.79

secondary cost 607.03 635.7 670.34 607.66 644.43 685.11

xix

409 case No. 25 26 27 28 29 30 31 32 33

TempUp Time 28 32.2 36.6 22.4 27.2 31.8 6.6 7 22

Decarb Time 11.2 11.4 11.6 12.8 12.8 13 23.8 27.8 20

Reduction time 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 16.4 16.4 16.4 16.4 16.4 16.4 16.4 16.4 16.4

ChCr 0 0 0 0 0 0 0 0 0

HCCr 7.41 7.278 7.278 7.291 7.278 7.278 7.29 7.279 7.274

FeNi 0 0 0 0 0 0 0 0 0

Ni 0 0 0 0 0 0 0 0 0

LCCr 0 0 0 0 0 0 0 0 0

FeMo 0 0 0 0 0 0 0 0 0

SS304 0 0 0 0 0 0 0 0 0

SS316 0 0 0 0 0 0 0 0 0

SS430 0 0 0 0 0 0 0 0 0

MSSC 0 3.272 7.417 0.444 4.561 8.623 1.552 5.643 9.505

FeSi 29.696 29.196 28.725 24.658 24.274 24.108 20.428 20.174 21.477

LCSiMn 0 0 0 0 0 0 0 0 0

Alum 0 0 0 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0 0 0 0

ElMn 0 0 0 0 0 0 0 0 0

Lime 62.757 60.846 59.655 49.606 48.658 48.229 39.11 38.505 39.725

Dolo 37.327 36.322 35.712 30.493 30.013 29.791 25.057 24.75 25.384

CaF2 31.732 30.901 30.389 26.03 25.632 25.439 21.495 21.228 21.768

O2-Lance 0 0 0 0 0 0 0 0 0

O2-bottom 24.671 27.945 31.351 20.696 24.298 27.917 16.456 20.086 24.68

H2O 7.828 7.985 8.135 9.153 9.216 9.305 12.323 13.006 12.038

N2 0.609 0.61 0.61 0.61 0.61 0.61 0.61 0.61 0.61

Ar 14.363 15.366 16.403 13.054 14.187 15.271 9.33 9.429 12.955


Processing time 64 68.4 73 60 64.8 69.6 55.2 59.6 66.8

primary cost 817.4 846.4 883.3 702.3 742.2 785.2 589.5 625.6 707.5

secondary cost 791.4 818.5 852.6 679.6 716.8 756.9 568.9 602.3 680.4

xx

409 case No. 34 35 36 37 38 39

TempUp Time 13.2 14.2 14.6 18.6 19.8 21

Decarb Time 14.4 14.6 15.4 10 10.2 10.4

Reduction time 2.2 2.2 2.2 2.2 2.2 2.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 16.4 16.4 16.4 16.4 16.4 16.4

ChCr 0 0 0 0 0 0

HCCr 42.654 22.423 2.196 42.646 22.423 2.197

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 64.036 86.524 109.004 64.26 86.507 108.755

FeSi 22.144 21.148 20.249 21.835 21.142 20.353

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 48.368 44.388 40.296 45.314 43.399 41.461

Dolo 29.432 27.372 25.243 27.856 26.857 25.847

CaF2 25.136 23.424 21.656 23.825 22.993 22.163

O2-Lance 12.613 13.212 14.011 0 0 0

O2-bottom 14.831 15.528 16.116 25.061 26.439 27.82

H2O 0 0 0 0 0 0

N2 0 0 0 0.917 0.917 0.918

Ar 21.054 21.556 22.165 29.404 30.132 30.864


Processing time 52.4 53.6 54.8 53.4 54.8 56.2

primary cost 1474.7 1256.8 1041.0 1499.5 1290.3 1080.2

secondary cost 1382.4 1162.9 945.3 1407.2 1196.4 984.7

xxi

409 case No. 40 41 42 43 44 45

TempUp Time 54.8 58 60.2 13.4 14.2 14.8

Decarb Time 14 14.2 15.4 14.2 14.6 14.8

Reduction time 2.2 2.2 2.2 2.2 2.2 2.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 16.4 16.4 16.4 16.4 16.4 16.4

ChCr 0 0 0 0 0 0

HCCr 42.575 22.383 2.179 42.652 22.418 2.196

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 62.516 84.467 106.424 63.297 85.961 108.402

FeSi 33.305 33.304 33.305 24.513 23.544 22.556

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 60.365 60.835 61.406 53.454 48.853 45.042

Dolo 35.636 35.885 36.192 32.072 29.687 27.698

CaF2 30.321 30.528 30.78 27.346 25.35 23.695

O2-Lance 0 0 0 12.812 13.409 14.209

O2-bottom 31.712 33.373 35.088 14.289 14.935 15.443

H2O 0 0 0 0 0 0

N2 0.403 0.403 0.403 1.123 1.156 1.173

Ar 18.986 19.566 20.103 11.578 11.764 11.905

Compressed air 0 0 0 9.048 9.373 9.506

Processing time 93.6 97 100.4 52.4 53.6 54.4

primary cost 1625.4 1429.04 1232.94 1451.47 1230.87 1011.33

secondary cost 1526.5 1328.19 1130.08 1358.06 1135.68 914.53

xxii

409 case No. 46 47 48 49 50 51

TempUp Time 12.6 14 15.4 12.8 14 15.8

Decarb Time 14.2 14.8 15.4 14.6 15 15.6

Reduction time 2.2 2.2 2.2 2.2 2.2 2.2

Deslagging time 3.2 3.2 3.2 6.2 6.2 6.2

Desulph time 11.4 11.4 11.4 14.4 14.4 14.4

ChCr 0 0 0 28.886 28.882 28.888

HCCr 22.427 22.423 22.418 0 0 0

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 82.173 86.411 90.66 77.47 81.656 85.956

FeSi 22.712 21.119 19.54 21.449 19.857 18.031

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 50.249 44.387 38.429 47.486 42.128 36.062

Dolo 30.408 27.372 24.267 28.97 26.186 23.05

CaF2 25.959 23.424 20.834 24.758 22.433 19.824

O2-Lance 11.813 13.212 14.81 11.81 13.41 14.814

O2-bottom 14.257 15.508 16.603 14.518 15.606 17.024

H2O 0 0 0 0 0 0

N2 0.612 0.612 0.612 0.612 0.612 0.612

Ar 18.982 19.726 20.625 19.314 19.823 20.814


Processing time 43.6 45.6 47.6 50.2 51.8 54.2

primary cost 1237.08 1245.5 1255.1 1373.5 1381.7 1390.4

secondary cost 1145.2 1151.6 1159.2 1281.4 1287.7 1294.5

xxiii

409 case No. 52 53 54 55 56 57

TempUp Time 11.4 15.8 20.2 5 5.6 5.6

Decarb Time 19.2 19 19.4 36.6 40.2 46

Reduction time 4.2 4.2 4.2 4.2 4.2 4.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 16.4 16.4 16.4 16.4 16.4 19.4

ChCr 0 0 0 0 0 0

HCCr 8.016 8.01 8.005 8.014 8.016 8.005

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 6.357 10.679 14.814 7.055 10.301 15.158

FeSi 15.099 14.544 14.431 13.354 13.291 13.152

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 32.197 28.923 27.373 24.348 26.629 23.784

Dolo 13.631 12.513 11.979 10.951 11.734 10.757

CaF2 4.726 4.355 4.178 3.836 4.094 3.771

O2-Lance 6.405 6.805 7.204 0 0 0

O2-bottom 14.132 17.247 20.583 18.135 21.835 25.529

H2O 0 0 0 0 0 0

N2 0 0 0 0 0 0

Ar 25.206 26.296 27.744 31.556 31.966 35.906


Processing time 57.4 61.6 66.4 68.4 72.6 81.4

primary cost 636.60 671.74 717.04 630.46 672.75 732.80

secondary cost 615.76 648.12 690.47 610.33 650.28 706.87

xxiv

Appendix 316 result

316 case No. 1 2 3 4 5 6

TempUp Time 26.4 25 25.2 24.6 23.6 22.4

Decarb Time 20 18 17.4 24.8 21.4 20

Reduction time 4.6 4.6 4.6 4.6 4.6 4.6

Deslagging time 8 8 8 8 8 8

Desulph time 16.4 16.4 16.4 16.4 16.4 16.4

ChCr 0 0 0 0 0 0

HCCr 38.139 13.874 9.265 33.228 16.634 0

FeNi 20.653 33.062 48.715 23.537 37.427 48.494

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 8.743 10.406 9.376 9.484 9.495 9.228

SS304 0 0 0 0 0 0

SS316 16.275 16.76 11.378 11.547 11.575 16.349

SS430 0 0 0 0 0 0

MSSC 0 0 0 0 0 0

FeSi 10.327 9.434 9.666 9.969 9.703 9.976

LCSiMn 11.855 12.764 12.193 12.461 12.476 12.151

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 51.412 56.399 53.686 51.809 50.956 51.223

Dolo 19.758 21.671 20.629 19.923 19.587 19.688

CaF2 9.005 9.865 9.403 9.082 8.927 8.978

O2-Lance 0 0 0 27.314 24.752 22.346

O2-bottom 25.604 23.328 23.198 25.046 23.454 22.08

H2O 0 0 0 0 0 0

N2 17.857 17.098 16.647 21.647 18.932 17.702

Ar 9.831 9.906 9.859 9.885 9.897 9.893


Processing time 75.4 72 71.6 78.4 74 71.4



xxv

316 case No. 7 8 9 10

TempUp Time 22 13 19.4 17

Decarb Time 18.8 25.8 33.6 42.4

Reduction time 4.6 3.2 3.2 3.2

Deslagging time 8 8 8 8

Desulph time 16.4 11.4 11.4 11.4

ChCr 0 0 0 11.108

HCCr 12.058 12.071 11.982 0

FeNi 29.941 47.685 30.562 37.491

Ni 0 0 0 0

LCCr 0 0 0 0

FeMo 9.344 9.333 9.263 8.151

SS304 0 0 0 0

SS316 35.329 20.859 44.816 16.218

SS430 0 0 0 0

MSSC 0 0 0 0

FeSi 19.779 13.624 13.523 12.497

LCSiMn 12.277 12.262 12.171 11.608

Alum 0 0 0 0

LCFeMn 0 0 0 0

ElMn 0 0 0 0

Lime 88.719 67.114 68.414 55.25

Dolo 34.102 25.805 26.303 21.245

CaF2 15.387 11.69 11.914 9.664

O2-Lance 0 0 0 36.791

O2-bottom 24.068 25.499 21.026 24.694

H2O 9.652 0 0 0

N2 4.856 27.733 5.974 32.133

Ar 8.798 7.889 5.328 5.471

Compressed air 0 0 21.91 0

Processing time 69.8 61.4 75.6 82


6

4263.30

6

4182.59

8

3897.5


6

4155.97

1

4070.90

1

3808.72

2

xxvi

316 case No. 11 12 13 14 15 16

TempUp Time 17 17 19.2 18.8 18.2 15.2

Decarb Time 42 41 38.8 39.2 40.4 45

Reduction time 3.2 3.2 3.2 3.2 3.2 3.2


Desulph time 11.4 11.4 11.4 11.4 11.4 11.4

ChCr 0 0 0 0 0 0

HCCr 12.262 15.264 13.939 12.123 13.801 5.325

FeNi 27.585 31.902 47.612 49.203 38.642 12.708

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 31.695 9.505 0 9.362 9.454 8.358

SS304 0 0 0 0 0 0

SS316 6.62 16.374 25.692 16.127 16.285 16.029

SS430 0 0 0 0 0 0

MSSC 0 0 0 0 0 0

FeSi 12.413 12.489 12.983 12.984 12.421 10.979

LCSiMn 12.413 12.489 12.122 12.301 12.421 11.802

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 57.101 60.807 63 60.136 60.475 55.264

Dolo 21.944 23.368 24.216 23.112 23.241 21.244

CaF2 9.986 10.616 10.987 10.497 10.558 9.661

O2-Lance 36.346 36.967 35.029 34.835 36.169 37.349

O2-bottom 24.468 25.094 25.227 25.06 24.99 23.467

H2O 0 0 0 0 0 0

N2 31.581 31.333 29.342 29.514 30.704 33.523

Ar 5.434 5.467 5.384 5.385 5.438 5.407


Processing time 81.6 81.6 80.6 80.6 81.2 82.8



xxvii

Appendix 430 result

430 case No. 1 2 3 4 5 6

TempUp Time 13.6 13.8 14.4 13 13.2 13.8

Decarb Time 38.6 36 33.8 40.8 38.8 35.4

Reduction time 4.6 4.6 4.6 4.6 4.6 4.6


Desulph time 12.4 12.4 12.4 12.4 12.4 12.4

ChCr 0 0 0 0 0 0

HCCr 43.778 21.639 0 43.777 21.637 0

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 0 16.667 36.577 0 16.735 36.699

FeSi 16.332 16.82 17.796 15.7 16.527 16.669

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 43.902 45.431 48.113 43.237 44.761 46.936

Dolo 10.893 11.278 11.966 10.716 11.11 11.668

CaF2 7.419 7.667 8.107 7.31 7.569 7.918

O2-Lance 0 0 0 25.319 22.999 20.602

O2-bottom 25.871 24.395 23.148 25.596 24.137 22.858

H2O 0 0 0 0 0 0

N2 23.634 22.884 22.504 25.519 25.337 23.816

Ar 7.114 7.139 7.135 7.116 7.138 7.14


Processing time 77.2 74.8 73.2 78.8 77 74.2



xxviii

430 case No. 7 8 9 10

TempUp Time 16.2 9 13.6 13.8

Decarb Time 30.6 30.2 36 43.8


Deslagging time 8 8 8 8

Desulph time 12.4 12.4 12.4 12.4

ChCr 0 0 0 27.408

HCCr 21.632 21.628 21.638 0

FeNi 0 0 0 0

Ni 0 0 0 0

LCCr 0 0 0 0

FeMo 0 0 0 0

SS304 0 0 0 0

SS316 0 0 0 0

SS430 0 0 0 0

MSSC 13.204 16.284 15.888 12.532

FeSi 30.546 18.352 19.444 16.653

LCSiMn 0 0 0 0

Alum 0 0 0 0

LCFeMn 0 0 0 0

ElMn 0 0 0 0

Lime 91.347 51.28 53.664 44.825

Dolo 23.076 12.785 13.388 11.13

CaF2 15.162 8.621 9.013 7.577

O2-Lance 0 0 22.799 24.78

O2-bottom 24.181 24.938 21.893 24.963

H2O 17.106 0 0 0

N2 3.977 29.919 4.827 30.07

Ar 6.179 10.536 7.139 7.133


Processing time 71.8 64.2 74.6 82.6


1

882.87 1004.48 1152.7

secondary cost (sek/ton) 967.8 842.94 964.08 1112.6

xxix

Appendix 201 result

201 case No. 1 2 3 4 5 6

TempUp Time 27.4 27.6 30 27 27 29.4

Decarb Time 11.2 11 11.8 11.4 11.4 11.8

Reduction time 4.6 4.6 4.6 4.6 4.6 4.6

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 9.4 9.4 9.4 9.4 9.4 9.4

ChCr 0 0 0 0 0 0

HCCr 9.415 9.646 23.687 9.404 9.861 23.836

FeNi 59.875 45.106 31.879 59.948 45.137 31.874

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 0 0 0 0 0 0

FeSi 30.019 30.533 32.212 28.019 29.165 31.513

LCSiMn 0 0 0 0 0 0

Alum 0 0 0 0 0 0

LCFeMn 74.762 74.695 74.726 74.914 74.789 74.756

ElMn 0 0 0 0 0 0

Lime 62.318 63.925 67.742 61.588 62.22 66.315

Dolo 27.782 28.507 30.185 27.459 27.749 29.555

CaF2 9.374 9.618 10.177 9.267 9.375 9.967

O2-Lance 0 0 0 14.368 14.599 16.992

O2-bottom 29.812 30.355 32.884 29.528 30.004 32.334

H2O 0 0 0 0 0 0

N2 12.39 12.491 13.49 12.624 12.827 13.432

Ar 4.967 5.052 5.054 4.975 5.055 5.053


Processing time 58.8 58.8 62 58.6 58.6 61.4



xxx

201 case No. 7 8 9 10 11 12

TempUp Time 26.6 26.6 26.6 24.8 24.8 24.8

Decarb Time 11.4 11.4 11.4 7.2 7.2 7.2

Reduction time 4.6 4.6 4.6 4.6 4.6 4.6

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 9.4 9.4 9.4 9.4 9.4 9.4

ChCr 0 0 0 0 0 0

HCCr 0 0 0 0 0 0

FeNi 0 0 0 41.976 44.71 44.853

Ni 18.341 13.501 8.853 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 0 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 0 0 0 0 0 0

FeSi 29.002 28.821 29.974 3.82 2.459 2.004

LCSiMn 0 0 0 102.141 101.994 99.518

Alum 0 0 0 0 0 0

LCFeMn 74.55 74.547 74.823 0 0 0

ElMn 0 0 0 0 0 0

Lime 61.181 61.935 63.377 51.672 51.682 50.993

Dolo 27.304 27.641 28.273 23.101 23.109 22.805

CaF2 9.226 9.334 9.55 7.821 7.824 7.723

O2-Lance 13.523 13.601 13.651 12.693 12.675 12.716

O2-bottom 29.549 29.724 29.879 26.215 26.177 26.217

H2O 0 0 0 0 0 0

N2 12.645 12.712 12.715 8.843 8.83 8.903

Ar 5.027 5.056 5.075 5.093 5.086 5.102


Processing time 58.2 58.2 58.2 52.2 52.2 52.2


1

2884.14

7

2369.77

5

2595.93

5

2552.8 2528.6


1

2839.06

3

2332.46 2552.76

2

2507.9 2483.9

xxxi

201 case No. 13 14 15 16 17 18 19 20 21

TempUp Time 25.6 25.6 25.6 25.8 25.6 25.8 27 15 25.8

Decarb Time 7.6 7.4 7.6 11 11 11 9.8 11.4 11

Reduction time 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 9.4 9.4 9.4 9.4 9.4 9.4 9.4 9.4 9.4

ChCr 0 0 0 0 0 0 0 0 0

HCCr 0 0 0 0 0 0 0 0 0

FeNi 41.983 41.856 41.775 40.496 40.653 40.527 41.093 43.346 40.768

Ni 0 0 0 0 0 0 0 0 0

LCCr 0 0 0 0 0 0 0 0 0

FeMo 0 0 0 0 0 0 0 0 0

SS304 0 0 0 0 0 0 0 0 0

SS316 0 0 0 0 0 0 0 0 0

SS430 0 0 0 0 0 0 0 0 0

MSSC 0 0 0 0 0 0 0 0 0

FeSi 25.65 25.405 25.971 27.775 28.472 28.511 34.707 23.865 27.8

LCSiMn 0 0 0 0 0 0 0 0 0

Alum 0 0 0 0 0 0 0 0 0

LCFeMn 0 0 0 75.464 74.389 73.405 73.217 74.274 74.448

ElMn 61.408 60.514 59.802 0 0 0 0 0 0

Lime 52.867 52.559 52.344 60.799 59.875 59.831 74.12 51.81 60.284

Dolo 23.626 23.489 23.401 27.122 26.722 26.703 32.999 23.158 26.896

CaF2 8 7.955 7.916 9.166 9.028 9.026 11.12 7.839 9.091

O2-Lance 12.978 12.994 12.999 13.199 13 13.018 0 0 13.21

O2-bottom 26.92 26.815 26.921 28.791 28.672 28.783 28.493 26.28 27.077

H2O 0 0 0 0 0 0 7.602 0 0

N2 9.173 9.046 9.233 12.282 12.206 12.35 4.498 13.281 5.39

Ar 5.047 5.053 5.055 5.055 5.056 5.062 5.053 5.994 5.06

Compressed air 0 0 0 0 0 0 0 0 8.643

Processing time 53.4 53.2 53.4 57 56.8 57 57 46.6 57


7

2773.39

7

2765.75

4

2395.71

6

2394.468 2384.63 2387.908 2302.136 2379.9


7

2715.23

1

2707.27 2337.20

3

2335.316 2325.572 2323.967 2243.611 2321.10

7

xxxiii

Appendix 2205 result

2205 case No. 1 2 3 4 5 6

TempUp Time 15.8 11.4 11.6 15 12.6 12

Decarb Time 37.8 34.6 37.6 35.8 35.8 38.6

Reduction time 8.2 8.2 8.2 8.2 8.2 8.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 11 11 11 11 11 11

ChCr 0 0 0 0 0 0

HCCr 42.626 0.695 0 38.64 11.005 4.154

FeNi 0 0 0 0 0 0

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 1.801 1.848 1.889 1.808 1.83 1.883

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 0 0 0 0 0 0

FeSi 12.815 13.199 13.892 13.331 14.031 13.569

LCSiMn 13.929 14.477 14.49 14.352 14.333 14.441

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 39.326 42.849 45.206 40.766 42.56 45.053

Dolo 17.697 19.257 20.297 18.34 19.134 20.228

CaF2 6.201 6.725 7.071 6.417 6.685 7.047

O2-Lance 0 0 0 14.109 11.687 11.165

O2-bottom 31.386 28.48 28.646 31.696 29.432 29.048

H2O 0 0 0 0 0 0

N2 21.679 17.537 20.566 18.779 18.504 21.394

Ar 8.58 8.67 8.669 8.611 8.584 8.64


Processing time 79 71.4 74.6 76.2 73.8 76



xxxiv

2205 case No. 7 8 9 10 11 12

TempUp Time 10.4 10.4 10.4 10.4 10.4 10.4

Decarb Time 39.6 38.2 37.8 38.6 38.2 38.2

Reduction time 8.2 8.2 8.2 8.2 8.2 8.2

Deslagging time 6.2 6.2 6.2 6.2 6.2 6.2

Desulph time 11 11 11 11 11 11

ChCr 0 0 0 0 0 0

HCCr 0 0 0 0 0 0

FeNi 16.007 3.475 3.572 3.463 3.475 3.461

Ni 0 0 0 0 0 0

LCCr 0 0 0 0 0 0

FeMo 0 0 0 4.848 0 0

SS304 0 0 0 0 0 0

SS316 0 0 0 0 0 0

SS430 0 0 0 0 0 0

MSSC 0 0 0 0 0 0

FeSi 11.135 11.121 11.119 9.82 11.121 11.121

LCSiMn 13 13.178 13.176 13.131 13.178 13.178

Alum 0 0 0 0 0 0

LCFeMn 0 0 0 0 0 0

ElMn 0 0 0 0 0 0

Lime 28.214 28.802 28.534 28.768 28.802 28.802

Dolo 12.805 13.067 12.94 13.048 13.067 13.067

CaF2 4.579 4.657 4.614 4.654 4.657 4.657

O2-Lance 9.621 9.608 9.607 9.773 9.608 9.608

O2-bottom 26.705 26.912 26.841 26.882 26.912 26.912

H2O 0 0 0 0 0 0

N2 23.403 21.73 21.393 21.984 21.73 21.73

Ar 8.685 8.674 8.673 8.643 8.674 8.674


Processing time 75.4 74 73.6 74.4 74 74


4

701.580

4

702.898

2

1641.69

5

701.5804 701.2097


6

690.443

1

691.668

7

1618.55

6

690.4431 690.0859

xxxv

201 case No. 13 14 15 16

TempUp Time 17.6 10.4 10.6 10.2

Decarb Time 35.8 29.6 42.2 44.4


Deslagging time 6.2 6.2 6.2 6.2

Desulph time 11 11 11 12.4

ChCr 0 0 0 0

HCCr 0 0 0 0

FeNi 3.5 4.183 3.349 0

Ni 0 0 0 0.697

LCCr 0 0 0 0

FeMo 0 0 0 0

SS304 0 0 0 0

SS316 0 0 0 0

SS430 0 0 0 0

MSSC 0 0 0 0

FeSi 15.274 8.532 11.117 11.011

LCSiMn 13.165 13.175 13.173 13.213

Alum 0 0 0 0

LCFeMn 0 0 0 0

ElMn 0 0 0 0

Lime 44.218 25.572 29.639 28.126

Dolo 19.873 11.646 13.437 12.767

CaF2 6.93 4.183 4.78 4.558

O2-Lance 0 0 9.805 9.433

O2-bottom 26.031 25.463 26.644 26.908

H2O 7.016 0 0 0

N2 30.347 34.575 23.125 22.933

Ar 5.666 5.337 4.502 6.606


Processing time 78.8 59.4 72.2 77


6

599.343

7

675.203 674.622

5 secondary cost (sek/ton) 672.384 589.335

5

664.19 665.628

8

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Optimization of the AO stainless steel processing cost by ...706106/FULLTEXT01.pdf · 5 Figure 1 Trend of stainless steel price from 2012 – 2013[3] 1.2 AOD/CLU The stainless steel