Determination of the Carbon-Saturated SiO2-CaO-TiOx Phase Diagram at 1773 K

• Published in: Journal of phase equilibria and diffusion Vol. 43; no. 5; pp. 547 - 553
• Main Authors: Murata, Takashi, Yamaguchi, Katsunori
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-10-2022; Springer Nature B.V
• Subjects: Calcium oxide; Ceramics; Composites; Copper; Crystallography and Scattering Methods; Engineering Thermodynamics; Fluxing; Glass; Graphite; Heat and Mass Transfer; Metallic Materials; Natural Materials; Phase diagrams; Physics; Physics and Astronomy; Platinum metals; Silicon dioxide; Slag; Solid phases; Solubility; Thermodynamics; Titanium dioxide; Titanium oxides; slag; pyrometallurgy; titanium oxide; precious metal smelting; phase equilibria
• ISSN: 1547-7037; 1863-7345; 1934-7243
• DOI: 10.1007/s11669-022-00997-y

In the present work, a pyrometallurgical process is considered, in which platinum group metals (PGMs) from the hydrometallurgical residue containing mainly TiO
2
are concentrated in a metal phase with Cu as a collector, and TiO
2
is separated into the slag phase, with SiO
2
and CaO as fluxing agents. Efficient separation is thought to be possible only if the slag remains a homogenous liquid, with no solid phases present. In this study, the phase diagram of the SiO
2
-CaO-TiO
x
system equilibrated with graphite and CO gas at 1773 K was experimentally determined to find the liquid slag composition region with a large solubility of TiO
x
. The results showed that at high TiO
x
slag concentrations, a reaction occurred with the graphite crucible to form solid TiC. Additionally, the solubility of TiO
x
in the slag increased as the ratio of mass%CaO/mass%SiO
2
decreased.