Mineralogical characterization of copper sulfide tailings using automated mineral liberation analysis: A case study of the Chambishi Copper Mine tailings

As ore grades constantly decline,more copper tailings,which still contain a considerable amount of unrecovered copper,are expected to be produced as a byproduct of froth flotation.This research reveals the occurrence mechanism of copper minerals in typical copper sulfide tailings using quantitative mineral liberation analysis(MLA)integrated with scanning electron microscopy–energy dispersive spectroscopy(SEM–EDS).A comprehensive mineralogical characterization was carried out,and the results showed that almost all copper minerals were highly disseminated within coarse gangue particles,except for 9.2wt%chalcopyrite that occurred in the 160–180μm size fraction.The predominant copper-bearing mineral was chalcopyrite,which was closely intergrown with orthoclase and muscovite rather than quartz.The flotation tailings sample still contained 3.28wt%liberated chalcopyrite and 3.13wt%liberated bornite because of their extremely fine granularity.The SEM–EDS analysis further demonstrated that copper minerals mainly occurred as fine dispersed and fully enclosed structures in gangue minerals.The information obtained from this research could offer useful references for recovering residual copper from flotation tailings.

Coal petrology characteristics of middlings from Qianjiaying fat coal mine

The objective of this paper is to evaluate the coal petrology characteristics of slack middlings(13–0.5 mm)of dense media separation and flotation middlings from Qianjiaying fat coal preparation plant.Phase composition,macerals distribution,microlithotype and mineral occurrence of the two middlings were studied by XRD analysis and polarized light microscopy observation.Macerals distribution and wettability of the float-and-sink products separated from the middlings after grinding was investigated to determine the liberation degree.Studies show that there are more vitrinite and mineral,but less inertinite in slack middlings than in flotation middlings.Macerals associated with mineral in slack middlings is 69.85%,by volume,which is 17.86%higher than that in flotation middlings.Minerals in slack middlings are dominated by pyrite and clay,which are disseminated with the diameter less than2 lm.The main mineral in flotation middlings is clay with size range of 2–20 lm.Single macerals in the slack middlings are diffcult to liberate due to the fne-grained minerals.After grinding,macerals associated with minerals in the slack middlings decrease to 46.73%,by volume,which is higher than in flotation middlings by 25.89%,by volume.For slack middlings with poor liberation degree,density fractions below1.8 g/cm3is hydrophobic with contact angle above 71.5°.For the well liberated flotation middlings,there is signifcant wettability difference among the float-and-sink products.This research is the theoretical basis to realize re-separation of middlings.