Abstract Gaseous reduction by hydrogen was performed for three types of hematite pellets, two from industry and one prepared in the laboratory. The mechanisms pellets were studied based on morphologies partially reduced samples. Two found, industrial being very similar. degree followed as a function time each type pellets. On basis reaction mechanism mathematical model developed. As pioneer effort, combined computational fluid dynamics approach flow mass transfer gas phase with diffusion...

A study on the formation mechanism of liquid calcium aluminate inclusions from MgO‐Al 2 O 3 spinel was carried out. It found that reacted with dissolved Ca in steel forming phase. Stability calculations showed good agreement experimental result. According to thermodynamic calculation, would form even at very low level content 1873 K. At lower temperatures, compound CaO‐2Al be stable phase spinelmetal interface. Potential sources during ladle processes were also discussed.

Viscosities of slags constitute an important physical property needed for understanding the mass transfer phenomena in metallurgical processes. Viscosity is also key that leads to a better structure slags. It well‐known viscosities silicate decrease with addition basic oxides due breaking network. The measurements slag often pose experimental challenges, especially respect choice materials. This paper takes up problems and various techniques adopted. Dynamic viscosity measurement, as...

Abstract The viscosities of solid‐liquid mixtures were experimentally determined for silicon oil‐paraffin system at room temperature and oxide mixture steelmaking temperature. use systems was to confirm the results high measurements, experimental conditions being very difficult control. oil‐ paraffin behaved Newtonian until particle fraction reached 0.15. At this fraction, started deviate from flow; though some average values could still be collected with uncertainty. Liquid‐2CaO.SiO 2...

Al–O equilibria in molten Fe–Al alloys were experimentally investigated. Molten steel with varying Al content (0.01–10 mass%) was equilibrated a pure Al2O3(s) crucible at 1873 K an Ar atmosphere 3 vol% H2. The oxygen of higher than 1.0 mass% found to be much lower that previous works, while the for less 1 slightly higher, resulting smaller equilibrium constant. interaction parameters as well constant reevaluated present study. deoxidation represented up 10.0 using parameters.

In the present work, a new modelling approach has been put forward to study slag-metal reactions. Sulphur refining in gas-stirred ladle taken as an example. A two-dimensional fluid dynamic model accounting for steel, slag and argon phases incorporated with thermodynamics of desulphurisation. Comparison results calculation plant data from Ovako Steel indicates that great potential. It opened up possibility developing process models based on fundamental equations.

AbstractAbstractIndustrial data were analysed to shed some light on the formation and growth of non-metallic inclusions during ladle treatment a particular grade tool steel, Orvar Supreme (Fe-0·39C-1·0Si-0·4Mn- 5·2Cr-1·0Mo-0·9V). Seven types detected in samples taken along processing evolution steel. The present found vary with various stages that evolution. While additions aluminium steel bath affect composition inclusions, only small number pure alumina agglomerated as clusters, observed...

Abstract Viscosities of some quaternary slags in the Al 2 O 3 ‐CaO‐MgO‐SiO system were measured using rotating cylinder method. Eight different slag compositions selected. These ranging high basicity region directly related to secondary steel making operations. The measurements carried out temperature range 1720 1910 K. this and its sub‐systems expressed as a function composition based on viscosity model developed earlier at KTH. iso‐viscosity contours relevant ladle calculated 1823 K 1873...

AbstractIn the present work, viscosities of some CaO–CaF2–SiO2 slags were measured using rotating cylinder method. The effects various volatile fluorine compounds on change in slag composition are discussed basis thermodynamic calculations. kinetic factors concerning escape fluorides under experimental conditions also examined. It was found that formation gaseous species SiF4 main source for compositional changes during viscosity measurements. In case CaO–CaF2–SiO2slags, would be somewhat...

AbstractAbstractSamples of ladle lining covered by glaze were taken from industrial ladles different ages at Uddeholm Tooling AB, Hagfors, Sweden. It was found in the samples and below slag line that a infiltrated layer an outer containing many MgO 'islands' various sizes. The microstructure infiltrating same as matrix layer. to decompose into compound 3CaO.Al2O3 liquid phase during cooling process. former along with tiny particles be one major sources inclusions degassing flotation periods...

A new thermogravimetric setup was developed to study direct reduction of iron oxide under well‐controlled experimental conditions. Pure and industrial hematite samples were isothermally reduced by hydrogen carbon monoxide gaseous mixtures. Influences gas composition, flow rate, temperature on investigated. Reduction rates obtained using the higher compared conventional method. This difference due time required replace inert with reactant in method, which led lower rate at initial stage....

This study focuses on the viscosities of synthetic slags used in secondary refining operations. Typically, these contain mainly CaO, Al2O3, MgO and SiO2. The data for LF slag are a model gas-stirred ladle to evaluate effect viscosity variations predicted parameters close slag/steel interface. results show that significantly affect It is therefore necessary control composition carefully during production.

AbstractAbstractThe present study was carried out to investigate the impact of slag– refractory lining reactions on formation inclusions during ladle treatment steel. The experiments were conducted an industrial scale in at Uddeholm Tooling AB Hagfors, Sweden. inclusion chemistry and population studied along with composition glaze, taken from lining. steel classified into four groups according Swedish standard SS 111116. SEM/EDS analyses identify phases both glaze. number before deoxidation...

AbstractAbstractAn experimental study was carried out at Uddeholm Tooling, Hagfors, Sweden to examine the impact of ladle glaze on formation non-metallic inclusions during treatment process. Steel samples were taken various stages process and from ladles different ages. Inclusion numbers counted under an optical microscope. It found that total number increased with age before deoxidation end treatment. The increase substantial after had been used more than 18 times. Inclusions having...