Abstract:
The postulation that primary platinum group metal (PGM) matte
will chemically react with magnesia-chrome bricks when temperatures
exceed 1500°C was tested. Magnesia-chrome brick samples
were heated in contact with matte at 1300°C to 1750°C for 30
minutes, after which the refractory samples were analysed using
reflected light microscopy and scanning electron microscopy. The
samples were all completely penetrated by matte. As the
temperature increased the matte also penetrated the fused
aggregate grains and disintegrated them. The chromium concentration
of the matte inside the refractory samples was found to be
slightly higher than that of the bulk matte. At temperatures of
1500˚C and higher, MgO, FeO, and magnesium-rich silicate crystals
could be identified in the matte directly adjacent to the refractorymatte
interface. Phase relations clearly indicated that chemical
reactions take place between primary PGM matte and the magnesiachrome
refractory material at temperatures above 1500°C, but that
these reactions are more complex than expected from FactSAGE®
calculations.
