Klaus Hennesen

Tracer diffusivity of Si31 in CaO-SiO2 melts at 1600°C

In the present paper, the tracer diffusivity of Si31 was measured in CaO-SiO2 melts at 1600°C. The Si31 isotope was produced by neutron bombardment in a nuclear reactor, and the capillary technique was used in the diffusion experiments. The diffusivities obtained, decrease with increasing silica content, and are lower by approximately one order of magnitude than the diffusivity of Ca45 determined previously.

Tracer diffusivity of Ca45and electrical conductivity in CaO-SiO2 melts

The tracer diffusivity of Ca45 has been measured in CaO-SiO2 melts in the temperature range 1500 to 1700°C. In addition the electrical conductivity has been determined. Both properties decrease with increasing silica content. The activation energies (~30 kcal g-atom−1) are of the same order of magnitude. The electrical conductivity as computed from the diffusivity on the assumption that the total current is transported exclusively by divalent calcium ions and that the usual Nernst-Einstein relationship is valid, is somewhat lower than the measured electrical conductivity with the difference increasing with increasing silica content.