The melt reduction furnace has been used
successfully to recover residual cobalt from converter slags. For example, a
30 tonne sample of converter slag containing 0.6% Co ex Rustenburg Platinum
Mines was smelted to produce an alloy containing 4.5% Co, which, because it
was finely granulated as soon as it was poured from the furnace, was
rendered treatable by a subsequent hydrometallurgical operation.
Various cobalt-bearing heterogenite
concentrates ex the Congo containing between 2% and 9% Co have been smelted
to produce metallic products containing between 22% and 45% Co.