JOGMEC金属資源の生産技術に関する基礎研究の成果

[3K0401-10-05] Microencapsulation using Fe²⁺ and PO₄^3– for Selective Flotation of Chalcopyrite and Molybdenite

Ilhwan Park¹, ○Seunggwan Hong¹, Sanghee Jeon¹, Mayumi Ito¹, Naoki Hiroyoshi¹ (1. Hokkaido university)

The chairman: Taro KAMIYA (JOGMEC)

Keywords:Selective flotation, Molybdenite, Chalcopyrite, Hydrophilic coating

Conventional Cu-Mo flotation uses sodium hydrosulfide (NaHS) as a copper depressant, which may emit toxic hydrogen sulfide gas (H₂S) when pH becomes lower than 9.5. In this study, microencapsulation technique using Fe²⁺ and PO₄^3– (i.e., phosphate-assisted microencapsulation (PAME)) was investigated to depress chalcopyrite floatability in Cu-Mo flotation.
The coating experiments were carried out by mixing a mineral sample (chalcopyrite or molybdenite) in solution containing Fe²⁺ and PO₄^3–. The results of solution analysis and surface analysis (SEM-EDX and XPS) for treated minerals showed that Fe—P—O containing coatings were formed only on the surface of chalcopyrite. Cyclic voltammetry (CV) of mineral electrodes showed that Fe²⁺ is oxidized to Fe³⁺ on chalcopyrite surface but not on molybdenite surface. These results suggest that on chalcopyrite surface, Fe²⁺ is oxidized to Fe³⁺ and reacted with PO₄^3– to form ferric phosphate (FePO₄) coating.