Concentrators:
Crushers and grinding mills are used to liberate the sulfide minerals
from the other materials to begin the recovery of the Pd and Pt sulfide
minerals.
The floatation follows the grinding stage. Flotation reagents are
added to aid in the separation of the Pd and Pt sulfide minerals
from other
material. In this process the slurry is agitated while air is induced
into the system. This froth layer is then collected as concentrate
and transported to the smelter.
Smelter:
Concentrate from the Stillwater and East Boulder Mines is sampled,
dried, and pneumatically conveyed to a concentrate bin where it
is fed to the
electric furnace.
The electric furnace is rectangular with 3 in-line
electrodes. Furnace matte is tapped approximately every 4-8 hours
into ladles and granulated
in preparation for converting in TBRCs (Top Blown Rotary Converters).
Converter matte is poured into ladles, granulated, dried and transported
to the Refinery.
Refinery:
The flow of material through the refining process follows a series
of circuits in which palladium and other PGMs follow one path,
other materials are
separated and follow other paths that dissolve one metal, but not
others. The three stage leach and metal recovery process selectively
extracts
nickel, iron, copper and other metals from the Platinum Group Metal
(PGM) that
result in a higher grade PGM filter cake being produced at the
Stillwater base metals refinery for shipment to third party refiners. |