The direct alloying of the steel is attractive as it minimizes alloying cost, total energy consumption and CO2 emissions, compared with ferroalloys. This allying technique is in use for high alloyed (stainless), low alloyed and carbon steel. The elements reviewed include chromium, nickel, molybdenum, vanadium and manganese. Raw materials used to this purpose are lump ores, ore fines, special slags, self-reducing briquettes and others. For the development of this technique, tools like thermodynamic modelling, testing in induction furnaces of several scales and industrial tests have been instrumental. This paper summarizes the fundamental and industrial efforts carried out to develop and employ direct alloying in Japan, Russia, China and other steelmaking countries

1. Direct alloying of steel: a review of
studies at lab and industrial scale
Jorge Madias
Metallon, San Nicolas, Argentina
Consultant

2. Content
Introduction
Chromium
Nickel
Molybdenum
Vanadium
Manganese
Conclusions

3. About metallon
A consulting & training company for the steel &
foundry industry, based in San Nicolas, Argentina
Technical assistance
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Met Lab services
Library services

4. Introduction
Drivers behing preparation of the review
Consult by a steel company testing in small scale
manganese ore addition to replace
ferromanganese, for production of rebar, wire rod
and shapes (EAF – LMF - billet casting)
Consult by a steel company in order lo lower
ferroalloys cost for rebar steel production (EAF –
LMF – billet casting )
Consult by a supplier to a stainless steel producer
for use of chromite ore to replace FeCr (EAF –
AOD – ingot casting)

5. Chromium
JFE Steel (formerly Kawasaki Steel)
More than three decades of direct alloying for ferritic (and
some austenitic) stainless steel
1986 Nishinomiya
Start of smelting reduction of chromite ore
 SR K-BOP – DC K-BOP – RH - CC
1994 Chiba Nr. 4
New plant for smelting reduction
 SR-KGC – DC-KGC – VOD – CC
2004 Chiba Nr. 4
Scrap and hot metal reservoir / J-FIRST
STAR furnace for dust & slag recycling
2017 Chiba Nr. 4
Burner to decrease energy consumption

6. Chromium
JFE Steel
Nishinomiya – 1986
First industrial use of the process

7. Chromium
JFE Steel
Chiba Nr. 4 – 1994
New plant for stainless steel

8. Chromium
JFE Steel
Chiba Nr. 4 – 2004
J-First: scrap melting & hot metal reservoir
STAR: shaft furnace for dust & slag recycling

9. Chromium
JFE Steel
Chiba Nr. 4 - 2017
Burner to decrease energy consumption

10. Chromium
JFE Steel
Particular conditions
Low use of scrap – lower energy requirements
Typical Japanese hot metal pretreatment (Si and P)
Some Cr loss to dust and slag
Cr partition coefficient = %Crslag/%Crsteel x 0.3 aFeO
Introduction of dust and slag recovery in dedicated furnace
Improvements in energy consumption to keep the
process competitive
Higher oxygen supply
Failed, do to increased dust generation and lower Fe and
Cr yield
Post combustion
Failed, do to low heat transfer and lower refractory life
Burner for preheating the ore
Success

11. Chromium
British Steel Teeside R&D – 1997
Aim: to develop a process for smelting reduction of
chromite ore using coal and oxygen
Theoretical evaluation
Experimental program (two pilot 3t BOF)
Conclusions
High carbon (>5%) required, for high Cr yield
Not adequate for AOD further treatment
High temperature (>1600ºC) necessary for high Cr yield
Slag foaming control developed
Need for hot metal desiliciation and dephosphorization
Two alternative process routes proposed

12. Chromium
British Steel Teeside R&D – 1997
Two alternative process routes proposed

13. Chromium
Sweden 2012-2016
Royal Institute of Technology, Stockholm
Lulea University of Technology, Lulea
Swerea MEFOS, Lulea
Fundamental study aiming to direct alloying in EAF
TGA
Lab induction furnace (0.1, 0.2, 0.5 kg)
Role of iron/iron oxide and slag chemistry on reduction of
chromite by graphite
Induction furnace (7 and 80 kg)
Reduction of ore-mill scale-petroleum coke self-reducing
briquettes

14. Chromium
Sweden 2012-2016

15. Chromium
Other studies
Donetsk Metallurgical Plant 1987-1994
EAF
Chromite ore + lime (mechanically mixed, or premelt)
82-100% yield
0.4% Cr addition through ore
CMRDI, Egypt - 2015
To use low grade chromite ore
Tests in 5 kg SAF
Chromite ore, coal and mill scale
Obtention of high Cr alloy containing 18Cr–3.7C–0.5Mn–
1.5Si

16. Nickel
Yurga Institute of Technology, Novokuznetsk, Russia 2016-
2017
Thermodynamic study
Reduction of nickel from its oxide, with carbón
Tests in 10 t EAF (Institute)
45% Nickel concentrate obtained by beneficiation of
polymetallic manganiferous materials
Coke from EVRAZ ZSMK
Briquetting with a binder
Charging in the bucket or onto the liquid heel
Carbon steel scrap and lime
Tests in 60 t EAF (Stal NK Limited)
Stainless Steel
Ni yield 97-98%

17. Molybdenum
Royal Institute of Technology, Sweden 2010-
Evaporation rate of Mo in mixtures with CaO or MgO up
to 200ºC
High temperature DRX and TGA
Lab induction furnace
CaMoO4; MgMoO4; mixes of MoO3 with CaO or MgO
Reduction with C
CaO + MoO3 reduction with C viable
Further lab study (with Uddeholm)
Fe2MoO4 synthesis and reduction, to avoid volatilization
Studies on direct alloying with Mo precursors continue
currently under the frame the Jernkontoret´s Project for
ECO steelmaking

18. Molybdenum
Wuhan University of Science & Technology, China
2013-2014
Shijiazhuang Iron and Steel Co., China
Silico-thermic reduction of MoO3
TGA-DTA tests to study volatilization
MoO3+FeSi + MgO or CaO/CaF2
Tests in 15 kg induction furnace
 Self-reducing briquette MoO3+FeSi + CaO/CaF2
95% yield
Tests in 60 t ladle
42CrMo steel
Addition to the BOF stream into the ladle during tapping,
at 1/3 of steel in the ladle
Yield around 98%
No changes in inclusions or defects

19. Vanadium
Soviet Union / Russia
Use of V converter slag for direct alloying
Coming from the treatment of high V-Ti hot metal from
titano-magnetite ores
Practiced in several EAF plants in late XX century
Ural Railroad Car Plant (UVZ), the
Nizhni-Tagil
Magnitogorsk
Saldinskii Metallurgical Plant
Pervoural'sk Dinas Plant,
Krivoi Rog
Moscow "Serp i Molot“, and others
Reduction with FeSi and coke breeze

20. Vanadium
Siberian State Industrial
Univ., Novokuznetsk,
Russia – 2014
Use of vanadium
converter slag (16%
V2O5) for direct alloying
Thermodynamics
assessment of reduction
in a 110 t ladle with FeSi
and coke fines, under
nitrogen stirring

21. Vanadium
 Wuhan University of Science &
Technology, China 2014
 Shijiazhuang Iron and Steel Co., China
 Silicothermic reduction of V2O5
 Tests in 15 kg induction furnace
 Self-reducing briquette V2O5 + FeSi +
CaO + CaF2 (ten different mixtures
 Optimum briquette chemistry:
24%V2O5–30%FeSi–16%CaO–
30%CaF2
 96% yield
 Tests in 60 t ladle
 42CrV steel (V: 0,12%)
 Addition to the converter stream into
the ladle during tapping, at 1/3 of steel
in the ladle
 Yield around 96,5%
 No changes in inclusions or defects

22. Manganese
Soviet Union
1982-1986 Development by Donetsk
Polytechnical Institute at Azovstal
1.000.000 t of low C, Al-Si-Mn killed steel for
plates, processed during the period

23. Manganese
Russia – 2004
Siberian State University; KMK Relsy OOO; West Siberian
Metallurgical Combine
EAF tests
 To maximize replacement of silicon by low cost carbon
 To stabilize the recovery of manganese from the ores
Practice
 Deslagging oxidizing slag
 Charging low P manganese ore
 Placing coke breeze on molten oxide surface
 8-16% of Mn ore mass
 Adding FeSi 10-15 min after coke
Model to define influence of amount and timing of lime addition,
slag basicity, Mn ore amount
Optimum process time length determined
Temperature range for FeSi addition determined
Commercial practice at WSMC
 Carbon and low alloyed steels
 25 t EAF
 90-95% Mn yield; 83-85% Si yield

24. Manganese
Russia – 2015
Same partners as in previous slide
Tests in 25 t steel ladle with three briquetted mixes
Al–Mn–Si–Fe–C (7% Al, 25% Si, 27% Mn) – 39%
Mn ore, 20% dolomite, 2% binder
42% FeSi45 – 41% Mn ore – 12% dolomite – 4%
binder
17% FeSi75 – 43% Mn ore – 11% dolomite – 23%
CHP ash – 5% water
Steel temperature at addition 1610 – 1620ºC
78-88% Mn yield

25. Manganese
Others
Mexico 2003
MnO powder injection in 10 kg induction furnace
Cuba 2003-2006
3 t induction furnace tests with pirolusite Mn ore
Georgia, 2009
Briquetting of manganese carbonate
Development of a model for automatic control of the
direct alloying process

26. Conclusions
Advantages
Less total energy consumption and CO2 generation
In specific cases, lower cost
Drawbacks
Direct alloying complicates the steelmaking operation
and increases the quantities of energy and materials it
uses;
Direct alloying increases the volume of steelmaking
slag;
In some cases carbo-thermic production of ferroalloys
is replaced by more expensive alumino- or silico-
thermic methods

27. Conclusions
Despite its drawbacks, direct alloying continue to
be used in some countries, for specific conditions
Japan, for chromite ore smelting in stainless steel
production (JFE Steel Chiba No. 4)
Russia, for Mn and Cr addition to low carbon low
alloyed steels, and V recovery from converter slag
Recent R&D efforts aimed towards fundamentals
and application
China (Cr, V, W)
Sweden (Mo)

28. Jorge Madias
metallon, San Nicolas, Argentina
jorge.madias@metallon.com.ar