FLOTATION OF ULTRA-FINE SCHEELITE PARTICLES ASSISTED BY NANOBUBBLES
ZHOU Weiguang, OU Leming*, FENG Qiming, ZHANG Guofan, LU Yiping, SHI Qing, CHEN Hao
(School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China)
*Corresponding author E-mail: OU Le-ming (1026997310@qq.com)
ABSTRACT
It is well-known that the use of nanobubbles can significantly improve the flotation efficiency of
ultra-fine particles. However, this is mainly focused on coal and phosphate rock flotation. In the field of
nonferrous metal processing, the related research is few. In this paper, a small laboratory mechanical cell
associated with a specially-designed nanobubbles generator was used to investigate the effects of
nanobubbles on enhancing ultra-fine scheelite flotation. Nanobubbles were created and based on the
hydrodynamic cavitation principle through Venturi tubes. Comparative flotation tests were performed
using different tubes to evaluate the nanobubbles impact on the ultra-fine scheelite particle flotation
recovery. In order to better understand the nanobubbles enhanced ultra-fine scheelite flotation,
nanobubbles potential and size distribution were measured. The effect of nanobubbles on the particle
aggregation and scheelite particles potential were also studied through the turbidity tests, microscope tests
and zeta potential measurements. According to the results, the mean size of nanobubbles was about several
hundred nanometers, and the surface of nanobubbles was of highly negative charge in alkaline conditions.
The flotation recovery of ultra-fine scheelite particles was increased in the presence of nanobubbles. The
zeta potential measurements indicated that the repulsive forces between scheelite particles decreased when
nanobubbles existed. Through the turbidity tests and microscope tests, the promotion effect of nanobubbles
on particle coagulation could be verified more directly. The existence of nanobubbles in flotation system
promotes the particle aggregation, thus increasing particles apparent size and particles capture by bubbles,
which may be the fundamental reason why nanobubbles enhance ultra-fine scheelite flotation.
KEYWORDS
Hydrodynamic cavitation, Nano-bubbles, Ultrafine scheelite, Flotation