The conditions of Ca-reduction will be described briefly,
since the details were reported elsewhere [5–7]. The hydrogen
reduced scrap powder was mixed with 10 mass% powdery
anhydrous CaCl2 (95 mass% purity) in N2 gas atmosphere.
Ca shots (1–3 mm in diameter, 95 mass% purity) were added
to the mixture. The amount of Ca was adjusted to be 1.35
times the stoichiometric necessity assuming that it is oxidized
to CaO. About 3 kg of the mixture was charged into a
stainless steel vessel and 10 vessels were heated at 1223 K
in Ar atmosphere at 105 kPa for appointed duration, then
heated at 923 K for alloying. The product after Ca-reduction
was milled below 5.0 mm in N2 gas atmosphere.