Ironmaking for China 2012 1

nullnullAn Introduction to the Steel Industry (mainly in the USA)Sustainability: in the USSustainability: in the USIn 2008: 82 million tons of steel recycled at a the rate of 83.3% In 2006 (more detailed data): 70 million tons of steel recycled, at a rate 69%: 65% of re-bar 90% of structural beams 104% of automobiles!! 63% of steel cans 90% of appliances Energy requirement for recycled steel is 26% of that for primary steel. Every ton of steel recycled saves 3MWhr Recycling 1 ton of steel saves 1.25 tons of iron ore, 0.7 tons of coal and 0.06 tons of limestone Professor ElliottProfessor ElliottDavid RobertsonWorld production 2007nullMore recent dataMore recent dataFor 2011 the data for China are 684 million tonnes per annum, well above the 638 figure in 2010. Increases over the past 5 years are shown in the Table below, so the pace may be slowing? USA - in just 38 years!USA - in just 38 years! 1972 217 121 89 18 77 14,500 2002 30 92 46 48 63 6,400 USA # Usable BF’s Crude steel. Million mt BF Iron Pdn. Million mt EAF % of Pdn. Iron Ore Pdn. Million mt Iron Ore Mine Employment2010 ? 80 31 60 27 3,530 nullSource: AIOA & AISINorth American Blast Furnace Ironmaking nullIronmakers in USASummary (primary steel)Summary (primary steel)2002 Eleven independent domestic companies One multi-national (Ispat) 2012 Two independent domestic companies USS (5 plants in US); AK (2 US plants) (USS also now a multi-national) Severstal – multi-national (1 plant) ArcelorMittal – multi-national (3 plants) nullMini-mills in USA (Slide1)nullMini-mills in USA (Slide2)Summary (mini-mill sector)Many medium-sized companies All over the country Innovative and competitive How do we make steel?How do we make steel?Either from iron ore or from scrap. More than 60% of the raw steel produced in the US is now made from scrap Steel is highly recyclable, so contributes greatly to sustainability nullPAGE 1Start with Iron OreFrom R. E. Mazurek, Cleveland CliffsnullStates of Iron (Fe)IRON ORE REDUCTIONFrom R. E. Mazurek, Cleveland CliffsnullPAGE 2 - DecisionsDirect Reduction (solid) 600º - 1400º COR Smelting (liquid) >1535º CFrom R. E. Mazurek, Cleveland CliffsnullPAGE 3Get a GOOD Furnace Put it in a good place! LOCATION,LOCATION,LOCATIONFrom R. E. Mazurek, Cleveland CliffsnullDirect Reduced Iron Pellets & Lump (DRI) Hot Briquetted Iron (HBI) Iron Carbide Pig Iron Liquid hot metal cast bars, pyramids granulated From R. E. Mazurek, Cleveland CliffsnullBlast furnaces (coke-based) will remain dominant for the foreseeable future Iron oxides reduced by CO and carbon. Molten iron productIronmakingnullTuyere Inputs • Wind (oxygen, nitrogen) • Moisture • Coal, oil or gas Taphole Outputs • Liquid Iron • Liquid slag Top Output • BF Gas Top Inputs • Coke • Burden 900 oC isotherm Figure 1 Inputs and outputs in a blast furnacenullnull14 m dia 35 m high14 m max IDnullJSW No 3 Blast Furnace: recent operating data Daily Production 7,800 t/d Productivity 2.28 t/d/m3 (WV) Coke rate 400 kg/t PCI Rate 100 kg/t Slag Rate 300 kg/t Hot Blast Volume 5100 Nm3/min or 85 Nm3/sec Hot Blast Temperature 1250°C Oxygen Enrichment 6.2% Furnace Top Pressure 2.4 bar gauge (50 psia)Topics of Interest: IronmakingTopics of Interest: IronmakingRenewable fuels in the blast furnace to replace some of the coal in PCI Dry coke quenching (?) Low-Si hot metal Stove oxygen enrichment Oxygen blast furnace (CO2 easier to seq.) ITmk3 SteelmakingSteelmakingImpurities to be removed are: Carbon to CO Silicon to silica, fluxed with lime Phosphorus to calcium phosphate Sulfur to CaS Impurities to be avoided Nitrogen, use pure oxygen Hydrogen, avoid moisture scrapScale of SteelmakingScale of Steelmaking200 tons of steel refined in 20 minute “blow” Burning carbon at rate of 30 tph Pure oxygen flow 40 tph or 8 Nm3/second 99%. 99.5%, 99.9%, 100 ppm N2 Raw steel produced 9600 tpd Roughly matches blast furnace production CO gas recovered and re-used Oxide fume captured dry and recycled null7 m7nullnull Industry Issues Steel Imports Cyclical Financial Returns Capital Availability / Cost of BF Relines R & D cutbacks Mini-mill sector growth vs. integrated sector rationalization Natural gas pricing unpredictable; clouds future for domestic DR-based steelmaking Steel Imports to U.S.Steel Imports to U.S. 1998 Imports Iron Ore (million net tons) Displaced* (million gross tons) Semi-finished 6.8 9.4 Finished 34.7 50.8 Total 41.5 60.2From R. E. Mazurek, Cleveland CliffsnullBankruptcies (14 integrated companies from 1985 -2002; some returned without BF’s) Facility Closures (inefficient, or for environmental reasons – e.g. BF’s, coke plants, sinter plants) Downsized staff (smaller technical staff, limited Engineering & R&D; talent flight; greater dependency on “outsourced” services) Consolidation (e.g. AK/Armco; USS/National; Arcelormittal/Inland;) EAF replacing BF/BOF nullBuying offshore semi-finished slabs at lower than internal production cost Downstream focus of capital (rather than on hot end) Offshore investments (USS-Slovak Republic, Czech Republic) Offshore investors (80’s-Kawasaki, NKK; 90’s-Ispat-Inland; 00’s Severstal, Arcelor-Mittal) Exit from non-core assets (e.g. mining / pelletizing / coke production / transportation) Turns out not to have been a good decision, but who knows? DR or New Smelting Technology (has not been adopted, see next slide) New topic: MSE and Met. Eng. in the USANew topic: MSE and Met. Eng. in the USAMSE: 138 departments in the US (www.gradschools.com) Met. Eng: only 13 departments in the US Universities Metallurgical EngineeringUniversities Metallurgical EngineeringCarnegie-Mellon University Missouri University of Science and Tech University of Utah University of Alabama – Tuscaloosa Colorado School of Mines Michigan Tech Carnegie-MellonCarnegie-MellonProf R. J. Fruehan – has just retired Prof P.C. Pistorius - 45 yrs old Missouri S&TMissouri S&TProf. Kent D. Peaslee Prof. Mark E. Schlesinger (thermo) Prof. Von Richards (foundry) Prof. Jeff Smith (refractories)Individual ProfsIndividual ProfsDr. H.Y. Sohn, Utah, iron-making Dr. Brian Thomas, UIUC, con cast Dr. Yogesh Sahai, OSU, fluid flow Dr. Ramana Reddy, U Alabama, thermo Dr. T. Deb Roy, Penn State, welding Dr. Pat Taylor, CSM, plasma Steelmaking from ScrapSteelmaking from ScrapTo repeat -more than 60% of the steel in the US is produced from scrap The electric arc furnace (EAF) is used The Consteel process is an important variation on the theme of the EAF We describe Consteel here and will come back to it later nullnullnullnullnullConsteel ProcessConsteel ProcessConsteel photographConsteel photographnullConsteel vs bucket chargingConsteel vs bucket chargingContinuous SteelmakingContinuous SteelmakingNew process scheme developed by a team led by Dr. Kent Peaslee at Missouri S&T US Patent number 7,618,582 Continuous steel production and apparatus Awarded 2007Missouri S&T PatentMissouri S&T PatentFully continuous steelmaking from scrap Production rate can be varied between 30 and 200 tph Continuous operation time ≈ 1 week Maintenance down time ≈ 1 shift per week A series of near-equilibrium CSTR’s Consteel EAF + 3 refining vessels + tundish Use of scrap as major charge material nullmodified Consteel® EAF steel mass = 55 t main functions: melt, heat, de-C, de-POxidizer steel mass = 27 t main functions: de-C, de-P, de-O, float inclusions, homogenizeReducer steel mass = 27 t main functions: de-O, de-S, alloy float inclusions, homogenizeFinisher steel mass = 23.5 t main functions: alloy, de-S, float inclusions, homogenizeTundishLess space for new CS processLess space for new CS processSmaller vessels and equipment No ladle transport and ladle maintenance So a smaller melt-shop - 1/3 area of current EAF meltshop Decreased capital investment, operational cost, maintenance, man-hoursSafety and Health during CS operation Safety and Health during CS operation Less moving equipment No overhead transport of steel Cleaner melt shop due to reduced fugitive off-gases and dust Easy access to reactors Increased safety and healthier work place Decreased operational cost and man-hours/tonView of new processnullWe simulated existing ladle metallurgy furnace so that we could predict performance of the reactors in continuous steelmaking: How much argon do we need to use for stirring to get the required rate?Observation of LMF treatmentsObservation of LMF treatmentsDetailed measurements over time, recording all activities with video camera and heat sheets, including: additions, stirring, sampling, arcing, temperature 20 heats in the plant 12 heats of Al-killed steel at LMF 1 8 heats of Si-deoxidized steel at LMF 2 Each heat 25 – 30 steel samples (one every 30 – 90 sec) 3 – 6 slag samples (one every 5 – 10 min) METSIM model for ladle treatmentMETSIM model for ladle treatmentMETSIM is a process simulation software Mass balance of all components Heat 8 – LMF 1Heat 8 – LMF 1Heat 16 – LMF 2Heat 16 – LMF 2Mass transfer rate and stirring power Mass transfer rate and stirring power 0 - 63 scfm argonFLUENT SIMULATIONFLUENT SIMULATIONThank you.Thank you.