Matthias Reisinger - Tata Steel Consulting UK - Iron ore product quality – Understanding the needs of the steel industry
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Matthias Reisinger - Tata Steel Consulting UK - Iron ore product quality – Understanding the needs of the steel industry

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Matthias Reisinger delivered the presentation at 2014 Africa Iron Ore conference. ...

Matthias Reisinger delivered the presentation at 2014 Africa Iron Ore conference.

The Africa Iron Ore conference is the annual gathering for iron ore and stainless steel executives engaged in the African Region.

For more information about the event, please visit: http://www.informa.com.au/africaironoreconference14

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  • 1. www.tatasteelconsulting.comwww.tatasteelconsulting.com
  • 2. Iron Ore and Coal Consulting www.tatasteelconsulting.com Excellence with a global reach www.tatasteelconsulting.com
  • 3. Foreword UK-based multi-disciplinary consultancy company providing specialised services for the development of iron ore, coal and steel industry projects. www.tatasteelconsulting.com TS Consulting Excellence with a global reach  More than 40 years of proven track record in feasibility studies, market studies, benchmarking exercises for both iron ore and steel products Mining and Raw Materials Ironmaking Steelmaking and Casting Rolling Mills and Finishing Project Management Business Planning
  • 4. Foreword www.tatasteelconsulting.com TS Consulting Excellence with a global reach TS Consulting has in-depth understanding of the global markets for steel and iron ore.  Tata Steel Consulting is part of one of the World’s largest steel companies which purchases around 25Mt/y of iron ore for its integrated steel plants in Europe and produces 10Mt/y at its wholly owned mines in India  Expertise to assess the quality of a particular iron ore in respect to downstream processing (sintering, pelletising, ironmaking etc.)  Knowledge of geological, mineralogical and metallurgical aspects of a wide variety of iron ore deposit styles across the globe
  • 5. Foreword The Mining and Raw Materials Team has assisted a broad range of clients in public and private sectors all over the world. Clients sectors include: www.tatasteelconsulting.com TS Consulting Excellence with a global reach Junior Miners European Union (PHARE) Investment Banks Development Banks Metals Producers World Bank Management Consultancies Private Investors
  • 6. Iron Ore and Coal Consulting www.tatasteelconsulting.com Excellence with a global reach www.tatasteelconsulting.com
  • 7. Motivation www.tatasteelconsulting.com TS Consulting Excellence with a global reach Product Quality is a Key Area in Project Studies – Is it Really?  Product quality is increasingly often inadequately addressed in Technical Studies (Conceptual, Pre-Feasibility, Definitive Feasibility) “Growing technical inaccuracy” and “ Worrying technical corner cutting “ (The Mineral Corporation, 2014)  Vulnerability of projects to severe criticism by independent technical reviewers (acting on behalf of lenders) – Due Diligence
  • 8. Product Quality in Technical Studies (1) www.tatasteelconsulting.com TS Consulting Excellence with a global reach
  • 9. Product Quality in Technical Studies (2) www.tatasteelconsulting.com TS Consulting Excellence with a global reach Why is it important to know Quality Requirements?  Determination of processing requirements  Optimisation of product mix  Identification of target customers  Estimation of accurate selling price (premiums/penalties)  Avoid project delays and cost increases  Improvement of project robustness
  • 10. Iron Ore and Coal Consulting www.tatasteelconsulting.com Excellence with a global reach www.tatasteelconsulting.com
  • 11. Definition of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach What is Iron Ore?  Iron ore is any rock or mineral from which iron can be extracted economically  Iron ores are a mixture of iron oxides, iron (oxy)hydroxides, iron carbonates and other compounds collectively referred to as gangue  The principal ore minerals are hematite (Fe2O3), magnetite (FeO.Fe2O3), goethite (FeO.OH) and siderite (FeCO3, to a lesser extent)
  • 12. Definition of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach The most important Gangue Minerals that may occur are …  Silica SiO2 (or quartz) and silicates of calcium, magnesium, sodium etc.  Phosphates such as apatite (Ca5(PO4)3(F,Cl,OH)) and monazite ((Ce,La,Nd,Pr)PO4)  Sulphides such as pyrite (FeS2) and pyrrhotite (Fe1-xS)  Oxides of metals such as titanium, manganese and vanadium  Carbonates of calcium (calcite) and magnesium (dolomite)  Iron oxides may contain deleterious elements in mineral lattice!
  • 13. Production Routes to Steel (1) www.tatasteelconsulting.com TS Consulting Excellence with a global reach Source: worldsteel.org
  • 14. Production Routes to Steel (2) www.tatasteelconsulting.com TS Consulting Excellence with a global reach  There is no melting and no elimination of gangue as slag  Oxygen is removed – other constituents remain in direct reduced iron (DRI ) and increase in concentration !  The charge must be very permeable to the up-flow of reducing gas  The charge must be strong and not disintegrate  Sulphur in the iron ore feed is undesirable (<0.008% for Midrex) Direct Reduction (DR) – Midrex, HyL (1) © Midrex
  • 15. Production Routes to Steel (3) www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Direct Reduction (DR) Pellets are characterised by high %Fe and very low total acid gangue content (<2%). Minimal flux additions to concentrates prior to pelletising. Phosphorus and sulphur should be very low.  Traditionally Direct Reduction furnaces were fed with 15% high grade lump (64-68% Fe) to avoid pellet sticking (‘clustering’) but development of coating techniques (limestone, dolomite, etc. coated pellets) has reduced this problem considerably Direct Reduction (DR) – Midrex, HyL (2) © Tenova
  • 16. Iron Ore Products www.tatasteelconsulting.com TS Consulting Excellence with a global reach 5 Types of Iron Ore Products are traded internationally: Lump Fines / Sinter Feed Pellet Feed PelletsConcentrate
  • 17. Iron Ore Products www.tatasteelconsulting.com TS Consulting Excellence with a global reach 0.001 0.01 0.1 1 10 100 Particle Size (mm) Lump Fines / Sinter Feed Concentrate Pellet Feed Pellets Particle Size and Product Terminology …
  • 18. Iron Ore Products www.tatasteelconsulting.com TS Consulting Excellence with a global reach What defines Quality?  Chemical Composition  Mineralogy  Physical Properties  Metallurgical Properties important implications upon suitability for downstream ironmaking processes
  • 19. Metallurgical Properties www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Low Temperature Disintegration  Reduction Properties under Load  Reducibility  Metallisation  Swelling Of particular Importance for lump and pellets …
  • 20. Chemistry is not just about %Fe … www.tatasteelconsulting.com TS Consulting Excellence with a global reach © Royal Society of Chemistry
  • 21. Iron Ore and Coal Consulting www.tatasteelconsulting.com Excellence with a global reach www.tatasteelconsulting.com
  • 22. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Generally the higher the iron content (%Fe) the more attractive the iron ore.  ‘As-mined’ (or Run-of-mine) iron ores can range in iron content from 15-68%. The lower grade ores will require beneficiation of some kind whilst the higher grade ores can be sold directly to the customer and are termed ‘direct shipping ores’.  The amount of beneficiation required depends on both the original iron content and the required iron content in the final product. General Remarks
  • 23. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Silica is one of the largest constituents of most iron ores second only (in most cases) to iron. The silica content of an iron ore can range widely between 3–50%.  Any silica remaining in the ore after beneficiation must be removed into the slag during ironmaking in the blast furnace.  In the DR/EAF process route any silica not removed by beneficiation will remain in the DRI and be carried through to steelmaking. Silica (SiO2) SiO2
  • 24. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Silica does not cause downstream processing problems during iron and steelmaking but does have a substantial (negative) cost effect.  The presence of silica increases the acidity of the feed to ironmaking which must be offset by the addition of limestone or dolomite to obtain an acceptable basicity (in order to protect the basic refractory linings from chemical attack).  Silica is a main contributor to the slag volume produced which affects blast furnace productivity and energy usage. Silica [contd] SiO2
  • 25. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Like silica, alumina must be fluxed to remove it from the blast furnace and therefore constitutes a significant cost problem. Alumina levels of sinter are generally limited to < 2%.  The alumina content in the slag is critical to the slag viscosity (stickiness or fluidity) and efficient blast furnace operation.  Mills try to maximise the use of low cost ores and operate with higher slag alumina levels  Value-in-use assessment: model effects and costs incurred during iron- and steelmaking Alumina (Al2O3) Al2O3
  • 26. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  If the ore naturally possesses a high enough level of ‘basic fluxes’ the addition of limestone and dolomite may not be necessary - these ores are known as ‘self-fluxing’  Lime plays important role in removal of silica, alumina, phosphorus (P) and sulphur (S)  MgO also provides basicity and is commonly used in conjunction with lime (CaO)  Magnesia has a high natural affinity for sulphur and therefore acts ‘de-sulphurising’  ‘Basic’ (CaO, MgO) gangue in iron ores is advantageous but depresses Fe grade Lime (CaO) and Magnesia (MgO) CaO MgO
  • 27. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  P reports almost entirely into the hot metal / DRI  P in steel can have beneficial as well as harmful effects o 0.04% allowable in Structural Steel, 0.035% in Tool Steel  Many Australian ores are relatively high in phosphorus  Asian steelmakers may have little tolerance to absorb any higher proportion of high-P ores into their ferrous feed Phosphorus (P) - (Penalty Element) Source: Poveromo, 1999 P
  • 28. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  “… sulphur is frequently found in metallic ores, and, generally speaking, is more harmful to the metals, except gold, than other things. It is most harmful of all to iron…” [De re metallica, G. Agricola, 1494-1555, after The AISE Steel Foundation, 1998]  Sulphur increases blast furnace flux requirements, slag volume and coke rate, and can incur cost for separate hot metal desulphurisation stage  In Fe ores: target level <0.03% but Chinese Steel Mills have been accepting up to 0.1% S Sulphur (S) - (Penalty Element) S
  • 29. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Present in iron ores as silicates (feldspars, micas) or alkali chlorides (NaCl, KCl)  Alkalis promote the disintegration of coke and the formation of scaffolds and scabs on the blast furnace walls (accumulation within BF shaft due to low condensation temperature)  Alkali compounds react with lining refractories thereby shortening furnace campaign life  Generally (Na2O + K2O) <0.1% Alkalis (Na2O and K2O) - (Penalty Elements) Na2O K2O
  • 30. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  At high levels the presence of titania poses risk of blocking the BF hearth and tuyers with highly refractory titanium carbide (at lower levels – 3-5kg per tonne of hot metal – the formation of protective layers of titanium carbonitrides can be desirable) o Southern System Brazilian Hematite Fines : ~0.05% TiO2 o LKAB Magnetite Fines : ~0.40% TiO2 in LKAB Magnetite Fines  Some steel mills (e.g. Evraz at Nizhniy Tagil) have adapted their BF operation to allow the use of the titanium-bearing raw materials (up to 2.5% TiO2 in iron ore) Titania (TiO2) TiO2
  • 31. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  In a blast furnace, most of the vanadium ends up in the hot metal. The vanadium in the metal is then removed in Basic Oxygen Steelmaking (BOS) where it reports to the slag.  Vanadium levels of up to 0.3% (V) are typically acceptable for conventional steelmaking  Vanadium can in principle be recovered from the metal (Highveld process) or the BOS slag (roasting-leaching) but this is normally only viable >1% and >3-5%, respectively  Typically only small, specialised niche suppliers (New Zealand Steel, Evraz-Highveld and QIT) Vanadium (V) V
  • 32. Constituents of Iron Ore www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Even very small amounts of zinc and lead can cause major operational problems o Zn and Pb are highly volatile and present in high concentrations in BF flue dust and sludge o Iron ores: Zn < 0.008% or 8 ppm, Pb < 0.005% or 5 ppm  Any zinc is fumed (sublimed) off and deposited in the upper shaft of the blast furnace o Zn and ZnO attacks the refractories and forms scabs and scaffolds o Entire blast furnace charge may become supported on a zinc scaffold and suddenly collapse o Zn can also cause solidification of slag due to rapid drops in temperature Zinc (Zn) and Lead (Pb) - (Penalty Elements) Pb Zn
  • 33. From a Steelmaker’s Perspective www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Ores with low Fe contents and high levels of P/S/alkalis/Zn/Cr etc. are unattractive  Presence of ‘basic’ gangue (MgO, CaO) in iron ore helps to reduce costs (slag builder, fluxes)  Removing impurities during iron/steelmaking is normally expensive (Al2O3, P, etc.)  Blending of small quantities of low-quality ore is often impractical  Filling up the hot metal [P], [Ni], [Cr] etc. to the maximum undesirable as it will limit the freedom of scrap choice in the steel plant resulting in higher (clean) scrap costs Recap – Iron Ore Product Quality
  • 34. www.tatasteelconsulting.com Excellence with a global reach www.tatasteelconsulting.com
  • 35. Future Developments ?? www.tatasteelconsulting.com TS Consulting Excellence with a global reach China is Principal Consumer of Sea-borne Iron Ore (1) Source: World Steel Association (2011,2012)
  • 36. Future Developments ?? www.tatasteelconsulting.com TS Consulting Excellence with a global reach  As economy matures, trend is towards higher value-added (HVA) steel products o Automotive applications, deep drawing/canning steels, etc.  Poor ores not cost but quality problem in steel making o Very low levels of Cu, Ni, Co, V, Ti etc. required  Growing environmental pollution element (S, Cr, Pb, Zn etc.) – Problem of off-gas emissions, slag deposition etc. China is Principal Consumer of Sea-borne Iron Ore (2)
  • 37. Technical Studies www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Depend on variety of factors (burden composition, product mix, process configuration, steel slag use, environmental restrictions, etc.)  Impurities are introduced through variety of streams (iron ore, lime, dolomite, coke and coke breeze, steel scrap, recycle streams such as mill scale etc.)  Aim at products which are saleable to multiplicity of customers  Restricted use by few niche customers considerably reduces project robustness Permissible Levels differ from Steel Mill to Steel Mill
  • 38. Technical Studies www.tatasteelconsulting.com TS Consulting Excellence with a global reach  Scrutinise iron ore quality as early on as possible in the development  Consult experts with in-depth understanding of downstream processing requirements o Steel works will always show interest in additional supply o MoU or Off-take Agreements – severe penalties on deleterious elements  Be open in discussions with potential Off-takers Recommendations