4. Conclusion
An advantage of treating sulphide/oxide blends is that many
operations have commitments to produce a concentrate at a minimum
sulphur and copper content, which may not be achieved if
the ore types are treated independently. Traditional sulphidisation
flotation techniques, which are widely used on copper oxide ore,
can not be used in sulphide/oxide blends for simultaneous sulphide
and oxide copper flotation as the sulphidising reagent will
suppress the flotation of sulphide minerals as shown within this
case study.
N-octyl hydroxamate collectors such as AM28 can be used successfully
to recover the oxide mineral component in mixed copper
sulphide/oxide blends without reducing the recovery of the sulphide
minerals. This investigation showed that for a Minto composite
blend of 70 wt% sulphide and 30 wt% oxide, the rougher
scavenger copper recovery was 95.5%. The concentrate grade and
copper recovery after 1 stage of cleaning was 33.9% Cu and
78.5%, respectively. AM28 successfully recovered malachite and
minor azurite, which were present in Minto’s oxide ore. The sulphide
recovery for the blend composite was not adversely affected.
Lower copper sulphide recovery is one of the main concerns for
many operations in blending oxide ores with their main sulphide