HE Jian-feng, HUA Zhong-bao, ZENG Yong, WANG Yan-hong, TANG Hong-hu*, LIU Run-qing, SUN Wei

(School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China)

Abstract: The utilization of high-salinity and high-hardness seawater, brine water, high-recirculating flotation tailing water, and other high-salinity waters for the mineral flotation will be a necessary path for the development of the mineral processing industry in the water-shortage coastal areas in the future. The mechanism of the effect of high-concentration ions in these high-salinity waters on the mineral flotation has always been one of the hot research topics in the field of mineral processing. In this article, we have reviewed researches of domestic and foreign scholars on effects and mechanisms of seawater, brine water, high-recirculating flotation tailing water, and other high-salinity waters on the mineral flotation, and have systematically analyzed effects of ions in high-salinity waters on flotation bubbles, mineral surface properties, and flotation reagents. There are many positive effects of high-salinity waters on the mineral flotation. They include the reduction of the surface tension of bubbles, production of more and more stable bubbles, improvement of the formation probability of flotation foam, compression of double electric layer on the mineral surface, reduction of the electrostatic force between mineral particles, and reduction of the entrainment of fine-grained gangue minerals in the flotation process. Meanwhile, the ions in high-salinity waters can consume flotation reagents. Hydrophilic precipitants on the mineral surface formed by high-valence alkali metal ions under the strong alkaline condition resulted in the reduction of the mineral floatability and the beneficiation indicators. Regarding to the negative effects of high-salinity waters on the mineral flotation, it is believed that main countermeasures include to develop methods for eliminating the influence of high-calcium and magnesium ions, to develop high-tolerance reagents, and to desalinate and soften high-salinity waters. They are also inevitably focused key points for the mineral flotation by using high-salinity waters in the future.

Keywords: high-salinity water; mineral flotation; flotation reagents; flotation interface chemistry; water softening

ACTA MINERALOGICA SINICA Vol. 43, No. 5, 2023, Page 581