*Article* **Effect of Sodium Metabisulfite on Selective Flotation of Chalcopyrite and Molybdenite**

**Yuki Semoto <sup>1</sup> , Gde Pandhe Wisnu Suyantara 1,2 , Hajime Miki 1,\* , Keiko Sasaki 1,2 , Tsuyoshi Hirajima 1,3 , Yoshiyuki Tanaka <sup>4</sup> , Yuji Aoki <sup>3</sup> and Kumika Ura <sup>4</sup>**

	- kumika.ura.r3@smm-g.com (K.U.)

**Abstract:** Sodium metabisulfite (MBS) was used in this study for selective flotation of chalcopyrite and molybdenite. Microflotation tests of single and mixed minerals were performed to assess the floatability of chalcopyrite and molybdenite. The results of microflotation of single minerals showed that MBS treatment significantly depressed the floatability of chalcopyrite and slightly reduced the floatability of molybdenite. The results of microflotation of mixed minerals demonstrated that the MBS treatment could be used as a selective chalcopyrite depressant in the selective flotation of chalcopyrite and molybdenite. Furthermore, the addition of diesel oil or kerosene could significantly improve the separation efficiency of selective flotation of chalcopyrite and molybdenite using MBS treatment. A mechanism based on X-ray photoelectron spectroscopy analysis results is proposed in this study to explain the selective depressing effect of MBS on the flotation of chalcopyrite and molybdenite.

**Keywords:** chalcopyrite; molybdenite; sodium metabisulfite; diesel oil; kerosene; selective flotation
