In order to increase their production of steel plates to 7.5 million tons/year, ArcelorMittal Tubarão faced the challenge to increase sinter plant productivity from 34.00 t/d/m2 to 42.00 t/d/m2. This was achieved in June 2006 through three main actuators: raw materials, stabilization and optimization of the current equipment and implementation of new technologies.

The paper introduces a slop detection algorithm, based on imagestaken by a CMOS camera aimed at the converter mouth. Theproposed algorithm, with an accuracy and selectivity of 74%and 94% respectively, is relatively simple and can therefore easilybe used in on-line applications.

The action of ArcelorMittal Maizières in the domain ofphysical chemistry of metallurgical slags and liquid steel hasalways been sustained. In particular, this activity gave birthto several models among which the cell model that describesthe properties of metallurgical slags (and of liquid oxideinclusions) has a special place. This model, along with otherspecific models describing the metallic phases, has beenincluded in a home-built equilibrium calculation code CEQCSI(Chemical EQuilibrium Calculations for the Steel Industry)to allow easy calculations by non specialist users. Severalapplications to steel elaboration will be presented. An insightinto the development of new models such as the GeneralizedCentral Atom model is also given. The application domainof this latter model is high alloyed and segregated steelgrades and the same formalism is also used to improve theperformance of the cell model for slags.

ArcelorMittal Monlevade is an integrated plant with sinter plant,blast furnace, BOF, ladle furnace, continuous caster, and rolling mill,with a capacity of 1.2 million tpy. During the last years, Monlevadehas been raising the ladle free open index through refractory qualityimprovement and standardization of operational parameters. The mainactions were changing of the geometry of ladle well block and nozzle,use of two-layer sand, and control of sand residence time before BOFtapping. Based on these facts, the ladle free open index has increasedfrom 98.5 to 99.8% from 2002 to 2006.

Anthracite coal as fuel for iron ore sintering is compared withcoke breeze. Anthracite is lower in porosity, higher in density, andslower in combustion rate. With higher proportion of anthracite infuel, permeability of sinter bed tends to decrease resulting in lowersinter productivity. Higher fuel rate with more replacement of cokebreeze by anthracite is ascribed to the lower density of heat sourceparticles and to the lower heat value and more volatile matters ofanthracite. A smaller particle size for anthracite is recommended.Some subsidiary heat sources such as magnetite ore and mill scalecould be helpful for more uniform sintering.

CRM is studying the possibility to comply with stringent PMregulations by improving the collection efficiency of existingdedusting systems, in order to avoid investments in expensiveadditional abatement means. The idea is to agglomeratefine dust particles together or onto coarser ones by applyingultrasound to the dust laden waste gas flow, upstream of thededusting unit.

The growing demand of steel products in a rapidly developingeconomy and increasing levels of imports in the Arab Worldprogress the development of local steel production. The steelindustry develops along the processes most appropriate to localresources: DR processes and EAF operation.

Steel making based on scrap melting is a substantial sourceof electric disturbances, such as voltage fluctuations, flicker,harmonics and unbalance between phases: unless mitigated,they all will spread over the feeding grid, violate the gridcode, and disturb other users connected to the same grid.With SVC (Static Var Compensator) and/or STATCOM, griddisturbances can be efficiently and cost effectively mitigated,enabling the plant owner to meet the valid grid codes. Atthe same time, productivity can be increased and productioneconomy can be improved.
The paper presents SVC and STATCOM for steel plantapplications; goes into the latest technology, and highlights acouple of recent, state of the art installations and their benefitsin steel manufacturing.

Solid and liquid iron oxides exhibit characteristics ofsemiconductors. The semiconductive behavior also featuresin some slags containing iron oxide. This paper aims athighlighting some of the experimental indications of the roleof semiconductivity in electrical conduction, the chemicaldiffusion and in reaction kinetics at slag surfaces. It is nota thorough review of the subject matter but an attemptat shedding some light on the connection between theseproperties.

The policy adopted by Belgo Monlevade Steel Works, ArcelorMittal in order to reduce the waste amount sent to the industriallandfill is presented. The focus of this policy is to increase theinternal reutilization of the waste generated in the steel makingprocess. The implemented actions and the projected actionsin order to increase the internal reutilization, saving naturalresources and reducing costs are reported.

The scarcity and discrepancies in thermodynamic data in Ca andMg containing iron-basis systems is reviewed. The difficulties ofhandling the problems involving these elements in steel with classicalthermodynamic methods recommend the use of computationalthermodynamics. Examples of applications of this method to Caand Mg related problems in steelmaking are presented.

The clogging of the Submerged Entry Nozzle (SEN) duringbillet continuous casting of mid-carbon steel is studied.Clogging materials and inclusions in steel samples taken atladles, tundish and billets are investigated. The total oxygen onthe whole section of the billet is measured. Steel cleanliness atunsteady casting states, including cast start, ladle change, SENchange, cast end, and the special unsteady pouring periodinduced by SEN clogging, are studied. Fluid flow and inclusionmotion and entrapment to SEN surface are also simulated.

The recent projects and the new EAF orders indicate a newtrend in the furnace design proposing very big electric arcfurnaces. Concast, after the first successful installation in2003 of the 180 t EAF in Icdas, wants to reproduce the reallyoutstanding performances of this EAF with the new 220 tEAF producing 320 t/h. The equipment installed and thefurnace design will follow the “Ultra High Chemical Power”EAF indexes.
An analysis on the basic engineering parameters and theextrapolation of its performance are presented.

The mechanism of cleanness improvement with bubbles isreviewed. Bubbling through the down-leg snorkel of a RHhas been modelled. This process was then experimented ona RH in POSCO, allowing a significant reduction of theinclusion content of slabs.

The aim of the research is to produce an algorithm forscrap quality determination which can be on-line integratedin the combined process model. The method combines simplemetallurgical relationships for residual elements with completereduction in steel and complex distribution based assemblagesfor some other elements.

The attachment mechanism of inclusions to bubbles hasbeen studied with water model experiments under turbulentcondition. Change in particle-number concentration indicatesthat the removal rate follows first order kinetics. It increaseswith particle diameters and particle contact angles.

The first blast furnace at Monlevade Works, based on charcoal,started up in 1937. Since then the route blast furnace-oxygensteelmaking has been used. In the course of the time,Monlevade Works ironmaking area went past some changesuntil reaching the present situation: one sinter plant and oneblast furnace based on coke. This blast furnace started up inDecember 1999 and its nominal capacity is 1,040,000 thm/year. This paper aims at showing the evolution of blast furnaceoperational performance, within a seven year operation whichallowed a production of 1,103,935 thm in 2006.

Dissolution of ZrO2 oxide in synthetic CaO - Al2O3 - SiO2 -Na2O - B2O3 mould fluxes was investigated in situ using aConfocal Scanning Laser Microscope (CSLM). Evolution ofparticle radius with time is obtained exhibiting strong dependenceon temperature and basicity of the mould fluxes. Therate-limiting step of the dissolution process was discussed, andbasicity was shown to significantly influence the rate-limiting step.