Hector M. Henao

Experimental study of phase equilibria in the “SnO”–SiO2–“FeO” system at silica saturation, and fixed oxygen partial pressures at 1473 K

Abstract The partitioning of tin between the slag and metallic phases, and the effect of oxygen partial pressure on the slag liquidus at tridymite saturation in the “SnO”–SiO2–“FeO” system at 1473 K have been measured. The experimental methodology includes high temperature equilibration and quenching, followed by the analysis of the compositions of the oxide phases by means of electron probe X-ray microanalysis, and the analysis of the compositions of the metallic phases using inductively coupled plasma mass spectrometry. The activity coefficient of SnO in slag has been calculated to be 1.13 ± 0.06, and Henrys law is shown to be obeyed in the slag at least up to 0.20 mol fraction of SnO.

Solubility of nickel in slags equilibrated with Ni-S melt

To provide thermodynamic data for converting the nickel matte to liquid nickel, an experimental study was conducted in the phase equilibrium between the Ni-S melt and FeOX-SiO2, FeOX-CaO or CaO-Al2O3 based slag melted in a magnesia crucible at 1773 and 1873 K. pSO2 was controlled at 10.1 kPa while pO2 and pS2 ranged between those where NiO precipitated and Ni3S2 formed, respectively. The nickel content in the slag and the sulfur content in the metal at given pO2 and pS2 were smallest for the CaO-Al2O3 based slag. Both decreased with increasing temperature. At 1873 K, the content of nickel in the CaO-Al2O3 based slag at pO2 of 10 Pa (near the precipitation of NiO) was 4%, while the content of sulfur in alloy is 0.4 mass %. Thus, the CaO-Al2O3 base slag at 1873 K would be suitable for direct converting of Ni3S2 to metallic nickel. The distribution behavior of nickel between the slag and the Ni-S melt was discussed based on the concept of oxidic and sulfidic dissolution.