Abstract
A fundamental study was conducted on a new process for producing scandium (Sc) metal or aluminium–scandium (Al–Sc) alloy by the calciothermic reduction of scandium oxide (Sc2O3). In this study, aluminium (Al) and calcium chloride (CaCl2) were used as the collector metal and flux for the reduction respectively. A mixture of Sc2O3, Al and CaCl2 in a tantalum crucible was placed inside a stainless steel reaction container, and the feed mixture was reacted with calcium (Ca) vapour at 1273 K for 6 h. After the reduction experiment, the reaction product (CaO), CaCl2 flux and excess Ca reductant were removed from the obtained alloy sample by leaching with an aqueous solution. The formation of Al3Sc in the Al matrix phase of the alloy was confirmed by X-ray diffraction and electron microprobe analysis. This result indicates that Sc2O3 was successfully reduced to metallic Sc and alloyed in situ to form liquid Al–Sc alloy during the reduction. When Al was not used in the reduction experiment, a complex oxide (CaSc2O4) was formed, and the reduction was incomplete. This study demonstrates that the Al–Sc alloy can be directly produced by calciothermic reduction using CaCl2 flux and Al collector metal.
Published Version
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