Phase relations in the system Ca–Ta–O and thermodynamics of calcium tantalates in relation to calciothermic reduction of Ta2O5

Branched morphology of Nb powder particles fabricated by calciothermic reduction in CaCl2 melt

“…Ta 2 O 7 was reported in the molten CaCl[28,29]. Ca Ta O was also reported in the CaO-Ta 2 O 5 phase diagram[30]. Therefore, broccoli-like Ta particles may be formed via a tantalum complex oxide synthesized by a reaction of Ta 2 O 5 by CaO.…”

Carbon Nanotube Synthesis via the Calciothermic Reduction of Carbon Dioxide with Iron Additives

“…[1][2][3] Various transition metals can be directly reduced from their oxides with metallic calcium because of its strong reducing ability. Therefore, calciothermic reduction for industrial applications had been widely investigated by many research groups to date, and metallic titanium, 4-9 zirconium, 10,11 hafnium, 12 niobium, [13][14][15] tantalum, 16,17 nickel, 18 uranium, 19 and their alloys [20][21][22][23][24][25][26][27] can be successfully obtained via calciothermic reduction and advanced techniques. 28,29 Although carbon dioxide (CO 2 ) is an extremely stable chemical species in our environment, the chemical decomposition of CO 2 is an important technology for global environmental issues.…”