Masayasu Ohtani

The transfer of silicon from the gas phase to molten iron in the blast furnace

The mechanism of silicon transfer in a blast furnace has been studied. It is concluded that the contribution of slag-metal reaction to silicon increase in the metal will not be very important because of the slow rate of the reaction and high oxygen potential of slag in a blast furnace. By making use of kinetic and thermodynamic data, it is shown that the reaction of SiO containing gas with liquid iron of high carbon content takes an important role in the silicon transfer in a blast furnace.

Triplet correlation and pair potential functions in liquid neon and sodium

Abstract Recent neutron diffraction data for liquid neon and X-ray diffraction data for liquid sodium have been analyzed with the purpose of studying the triplet correlation function in these liquids by means of the method suggested by Egelstaff, Page and Heard. In both cases, it was found that the function H( Q ) which expresses the deviation from the superposition approximation indicates the deviation from zero and the effect of the pressure derivative of the structure factor to the function H( Q ) is little. Besides, the pair potentials have been investigated from these diffraction data at various pressures using the Born-Green equation. The pair potential functions obtained for three states of liquid neon are the Lennard-Jones type, whereas those obtained for liquid sodium with a provisional assumption based on the experimental data are of the long-range oscillatory type. The pair potentials obtained in this work are useful for the interpretation on the difference in the pressure dependence of the structure factor for liquid neon and sodium.

Coupling phenomena in the transfer of elements between a gas phase and iron melts

The simultaneous transfer of Si and C from a gas phase containing SiO and CO to liquid Fe-C alloys has been investigated. It was found that, although the silicon content of the melt increased with time as expected, the carbon content initially decreased, in spite of the fact that the carbon potential of the gas phase was above that of the liquid alloy. These phenomena are interpreted in terms of irreversible thermodynamics which shows that the overall transfer reactions are comprised of coupled reactions: SiO(g) + CO(g) →Si + CO2(g) andC + CO2(g) → 2CO(g). It is also shown that the simultaneous transfer of carbon and oxygen from gas mixtures of CO and CO2 to liquid iron occurs via the coupled reactions CO2(g) →O + CO(g) and 2CO(g) →C + CO2. In each case there is a predominant, or driving reaction which promotes the other.

Effective Interionic Potentials and Properties of Molten Noble and Transition Metals

Abstract Recent X-ray diffraction data on molten noble and transition metals have been used to calculate effective interionic potentials by means of the Born-Green equation. The results on the noble metals are compared with the generalized pseudopotential calculations of Moriarty. In all cases the potentions were found to be insensitive to temperature and to have long-range oscillations. The results suggest that the effective valence number is close to unity in these molten metals, this giving reasonable values of the electrical resistivity when calculated in the framework of the usual Ziman theory. The self-diffusion coefficients, viscosities and surface tensions were calculated from the poten-tials and radial distribution functions using the kinetic theory of fluids. Adequate agreement with experimental data was obtained.

Partial Structure Factors of Liquid Na—K and AI—Mg Alloys

Three partial structure factors Sij(Q) have been evaluated from the scattered X-ray intensities of liquid Na -K and Al - Mg alloys assuming that the Sij(Q) are independent of the relative abundance of the respective elements in the alloys. The functions Sii(Q) and Sjj(Q) and the reduced radial distribution functions Gii(r) and Gjj(r) obtained in this work are very similar to those observed in the respective pure liquid metals. In both cases, Sij(Q) and Gij(r) have maxima which lie in between those of the pure elements. From these results, liquid Na -K and Al -Mg alloys are interpreted as random mixing fluids. A comparison between the partial structure factors obtained in this work and those calculated from the hard sphere model was made. Adequate agreement was obtained on the low angle side of the first peak, but agreement on the whole pattern is not necessarily found. The electrical resistivity was calculated using Faber-Ziman’s theory and compared with experimental data.