Preparation of high-purity Ti–Si alloys by vacuum directional solidification

Novel Approach for the Simultaneous Recovery of Nd from Nd2O3-Containing Slag and the Preparation of High-Purity Si

“…The Si crystals first solidified at the beginning of the solidification process of Si alloys, and Nd and other elements formed low-melting phases (liquid phases) that finally solidified and agglomerated along the Si grain boundary. The segregation coefficients of Fe, Ti, V, Mn, Al, and Ca between solid to liquid Si were previously reported to be 6.4 × 10 –6 , 2.0 × 10 –6 , 4.0 × 10 –6 , 1.3 × 10 –5 , 8.0 × 10 –2 , and 8.0 × 10 –3 , respectively. , Although the segregation coefficient of Nd has not yet been reported, Nd likely agglomerated along the Si grain boundary, given that no Nd was detected in the Si grains.…”

Environmentally friendly approach for sustainable recycling of spent SCR catalysts and Al alloy scrap to prepare TiAl3 and low-Fe Al alloys

“…Based on the principles of environmental protection and easy removal of impurities, CaO and Al 2 O 3 were chosen as slagging agents (forming a TiO 2 -CaO-Al 2 O 3 slag system), because CaO cannot be reduced by Al (CaO is more stable than Al 2 O 3 ); 25 the introduced Ca impurity in the obtained Ti-Al alloy can be easily eliminated by volatilization. 32 The concentrations of the components in the TiO 2 -CaO-Al 2 O 3 slag system were determined to be 53, 20, and 27 wt%, respectively, as shown by the components at point a in the TiO 2 -CaO-Al 2 O 3 ternary isotherm phase diagram (see Fig. 1).…”

“…According to our previous research, 32 when a resistance furnace with a directional crystallization system (no electro-magnetic force) is used to separate a Ti-Si alloy to prepare TiSi 2 crystals, the separation of TiSi 2 crystals is poor, with many Si phases mixed with the TiSi 2 crystals, giving the TiSi 2 crystals insufficient density. This is because when the alloy melt is removed from the heating zone, an axial temperature gradient appears on the sample, which generates an axial viscosity gradient in the sample (the precipitated solid crystals in the lower region mix with the liquid, causing the viscosity of the lower region to be larger than that of the upper region).…”