Flotation Separation of Chalcopyrite and Molybdenite Assisted by Microencapsulation Using Ferrous and Phosphate Ions: Part I. Selective Coating Formation

Abstract

Porphyry Cu-Mo deposits, which are the most important sources of copper and molybdenum, are typically processed by flotation. In order to separate Cu and Mo minerals (mostly chalcopyrite and molybdenite), the strategy of depressing chalcopyrite while floating molybdenite has been widely adopted by using chalcopyrite depressants, such as NaHS, Na2S, and Nokes reagent. However, these depressants are potentially toxic due to their possibility to emit H2S gas. Thus, this study aims at developing a new concept for selectively depressing chalcopyrite via microencapsulation while using Fe2+ and PO43− forming Fe(III)PO4 coating. The cyclic voltammetry results indicated that Fe2+ can be oxidized to Fe3+ on the chalcopyrite surface, but not on the molybdenite surface, which arises from their different electrical properties. As a result of microencapsulation treatment using 1 mmol/L Fe2+ and 1 mmol/L PO43−, chalcopyrite was much more coated with FePO4 than molybdenite, which indicated that selective depression of chalcopyrite by the microencapsulation technique is highly achievable.

Carrier Flotation Using Coarse Pyrite for Improving the Recovery of Finely Ground Chalcopyrite: Development of Post-Process of Carrier Flotation to Separate Finely Ground Chalcopyrite Particles from Coarse Pyrite Particles

“…Thus, the dissolution of Cu compounds formed on the surface of pyrite via acid treatment significantly contributes to the detachment of fine chalcopyrite and coarse pyrite. Surface modification is an effective method of controlling mineral hydrophobicity [30][31][32]. The KAX adsorption on pyrite becomes easier when a CuS-like layer or its oxidized products, such as Cu(OH) 2 , can be formed on the surface of pyrite [33].…”

Advances in Selective Flotation and Leaching Process in Metallurgy

“…A review paper by Park et al [3] introduced recent depression techniques, including alternative inorganic/organic depressants as well as oxidation treatments involving the use of ozone (O 3 ), plasma, hydrogen peroxide (H 2 O 2 ), and electrolysis. Moreover, Park et al [4,5] developed a new depression technique (i.e., microencapsulation using ferrous and phosphate ions), which preferentially coated chalcopyrite (CuFeS 2 ) with ferric phosphate (FePO 4 ) layers rather than molybdenite (MoS 2 ). As a result, the floatability of chalcopyrite was selectively reduced, while molybdenite floated well by the addition of kerosene (Mo collector).…”

Investigation of chalcopyrite removal from low-grade molybdenite using response surface methodology and its effect on molybdenum trioxide morphology by roasting

“…18–21 Copper in the form of chalcopyrite (CuFeS 2 ) is one of the most important impurities in molybdenite concentrates. 22 Using nitric acid as a solvent and an oxidant, or using sodium dichromate, sodium chlorate, and hypochlorite as oxidants, leaching of molybdenite has been investigated by some researchers. 4 Padilla et al 13,23 used both sulfidation and leaching methods to decrease the chalcopyrite content and observed a selective elimination for copper and minimum molybdenum dissolution in a mixed solution of H 2 SO 4 –NaCl–O 2 with acceptable efficiency of around 96%.…”