Melting of Quartz–Leucoxene Concentrate with Dispersed Arc Heating.

Separation of titanium and silicon oxides in the melt of quartz–leucoxene concentrate of the Yarega deposit under diffuse arc heating was investigated. Melting was carried out in argon at atmospheric pressure at direct current in a graphite crucible with an arc power of ≈25 kW. The crucible with the material was the anode of the arc. The arc heating was dispersed by applying an axial magnetic field. At the same time, a diffuse anode spot with a current density of 8 A/cm² was formed on the surface of the material. The current–voltage parameters of the diffuse arc were investigated. As a result of melting, an oxide ingot consisting of two phases was obtained, one of which is enriched in titanium oxide, and the other in silicon oxide. However, the separation of these oxides did not occur completely because of the high cooling rate of the melt. Despite the low current density in the heating spot, the melt evaporated intensely. Evaporation occurred congruently. Owing to the high temperature of the bath mirror, no volatile titanium oxide evaporated along with the volatile silicon oxide. Condensation of the evaporated material occurred selectively. A condensate consisting almost entirely of SiO₂ was formed in the form of powder on the cooled surfaces near the crucible. The specific surface area of the powder was 120 m²/g. The evaporated TiO₂ was removed with the exhaust gas. [ABSTRACT FROM AUTHOR]