The Chingola refractory ore (CRO) refers to over 150 million tonnes of low-grade copper ores found on old dumps in the proximity of open pits around the town of Chingola in Zambia..
The hybrid leaching process can effectively leach the refractory cupriferous micas in the CRO under ambient conditions.
Agglomeration, acid curing and column leaching of the CRO enhanced overall copper dissolution to 60%.
Alternative approaches to direct leaching are explored. In an effort to reduce acid consumption, the ore is pretreated by desliming followed by flotation in order to reject acid consuming dolomites and non-copper bearing micas. However, 15–20% of copper is lost to the slimes fraction, and non-copper bearing mica minerals floated faster than the cupriferous mica (such as phlogopite and chlorite)..
The total copper (TCu) in the CRO is about 1.2 wt%, of which 0.4 wt% is acid soluble (ASCu) and 0.8 wt% acid insoluble (AICu). Thus, the ore is a mixture of copper ‘oxides’ (malachite with minor pseudo-malachite and chrysocolla), sulphides (bornite and chalcocite with minor chalcopyrite) and cupriferous micas as given in Table 1(a).
A hybrid leaching process to enhance the dissolution of cupriferous micas in the Chingola refractory ore.