THE SYSTEM Fe–Rh–S AT 900° AND 500°C

The condensed phase system Fe–Rh–S was studied by means of dry syntheses at 900° and 500°C. At 900°C, there are fields of γ(Fe,Rh) with up to 29.7 at.% Rh, α1(Fe,Rh) with 40–50.4 at.% Rh and γ(Rh,Fe) between 0 and 34.3 at.% Fe, Fe1− x S that dissolves up to 25.7 at.% Rh at 55 at.% S, sulfide melt centered on ~37.5 at.% S and 40 at.% Rh, Rh17S15 (up to 7.5 at.% Fe), Rh3S4, Rh2S3 and Rh2.75S7.25 (“RhS3”) dissolving up to 4 at.% Fe. At 500°C, α(Fe,Rh) contains up to 9.5 at.% Rh, α1(Fe,Rh) has 33.5–52.2 at.% Rh, followed by γ(Rh,Fe). Fe1− x S dissolves up to 2.8 at.% Rh at 52.5 at.% S. Thiospinel Fe(Fe0.08Rh1.92)S4 is associated with FeS2, Rh17S15 (up to 4 at.% Fe) and Rh2S3. “RhS3” contains less than 1 at.% Fe. The principal assemblages are defined for both temperatures. We discuss data from the partly studied Fe–Ni–Rh–S system and compare the partition patterns of Rh inferred from the current study with those from sulfide–PGE deposits.