Quartz and Hematite Activation by Zn, Ca and Mg Ions in the Cationic Flotation Route for Oxidized Zinc Ore

ABSTRACT

Anionic, cationic and cationic/anionic flotation is widely used in the concentration process for low-grade oxidized zinc ores. In the cationic flotation route, sodium silicate is used as a depressant for gangue minerals and amine as a collector for zinc minerals previously activated by sodium sulfide. However, the presence of polyvalent ions in aqueous solution can affect the surface properties of the various minerals and consequently, the selectivity of the process. This study evaluated the effect of Zn, Ca, and Mg ions, originated by the solubility of smithsonite and dolomite, on the surface properties of quartz and hematite. Microflotation tests showed the inefficiency of sodium silicate as a depressant for quartz in aqueous solution even when Zn, Ca, and Mg ions were not present. Activation of hematite by Zn ions was observed, impeding the separation of smithsonite and hematite (iron oxide). Results obtained from the microflotation and zeta potential tests were analyzed based on the speciation diagrams of the reagents and ions studied, as well as published studies.

KEYWORDS:

• Quartz
• hematite
• Zn
• Ca
• Mg ions
• sodium silicate
• sodium sulfide
• amine

Acknowledgments

The authors would like to thank the company Nexa Resources for funding the research studies and for the scholarship to Geraldo Magela Pereira Duarte, to CNPq for the researcher grant to Prof. Dr. Rosa Malena Fernandes Lima, and also to CAPES, CNPq and UFOP for the maintenance of the Engineering Department laboratories.

Disclosure statement

No potential conflict of interest was reported by the author(s).