Mineralogical Characterisation of an Ag–In-Bearing Polymetallic Ore with Regard to Its Mineral Separation Behaviour

Polymetallic ores always contain precious rare metals which have high economic value. There is a large-scale copper (Cu)–zinc (Zn)–stannum (Sn) polymetallic ore deposit in Dulong, Yunnan Province, China. The polymetallic ore deposit contains a lot of silver (Ag) and indium (In). In this paper, the polymetallic ore is investigated to explore the characteristics of its process mineralogy by X-ray diffraction (XRD), X-ray fluorescence (XRF), optical microscopy (OM), and electron probe micro-analyser (EMPA). The contents of the main valuable elements in the ore are Cu 0.20%, Zn 3.93%, Sn 0.47%, Fe 22.70% and S 9.90%. Cu, Zn, Sn, and Fe mainly occur in chalcopyrite, marmatite, cassiterite and magnetite, respectively. In addition, as rare metal elements, there are also Ag 4.9 g/t and In 90.50 g/t in the ore. Ag mainly occurs in matildite and an unknown mineral (Ag 0.75 (Zn, Fe) 0.25 S) and these two minerals are all enclosed and disseminated in marmatite. In does not form an independent mineral, but an isomorphism element which mainly occurs in marmatite. Based on the results of the process mineralogy and actual conditions, a feasible flowsheet for this polymetallic ore is designed and optimized. The industrial experimental results show that processing capacity of the plant and the indexes of the concentrates are improved.